Sample records for antimicrobial-resistant fecal bacteria

  1. Antimicrobial-Resistant Fecal Bacteria from Ceftiofur-Treated and Nonantimicrobial-Treated Comingled Beef Cows at a Cow-Calf Operation.

    PubMed

    Agga, Getahun E; Schmidt, John W; Arthur, Terrance M

    2016-10-01

    We compared the occurrences of 3rd-generation cephalosporin-resistant (3GC r ), tetracycline-resistant (TET r ), and trimethoprim-sulfamethoxazole-resistant (COT r ) Escherichia coli, 3GC r and nalidixic acid-resistant (NAL r ) Salmonella enterica, and erythromycin-resistant (ERY r ) enterococci from the fecal samples of ceftiofur-treated (n = 162) and nonantimicrobial-treated (n = 207) comingled beef cows ≥8 years old, for which complete antimicrobial treatment records were available. The prevalence of 3GC r (17%; n = 369), TET r (88%), COT r E. coli (22%), and ERY r enterococci (69%) was not significantly (p > 0.05) associated with ceftiofur treatment, prior history of other antimicrobial treatments, or duration of time between last antimicrobial treatment and sampling. 3GC r and NAL r S. enterica were not detected. The prevalence of tetB was significantly (p < 0.05) higher compared with tetA among TET r E. coli. However, the prevalence of tetA was significantly (p < 0.05) higher than tetB among 3GC r and COT r E. coli. There was a significant (p < 0.05) association between tetM and ermB among ERY r enterococci. In conclusion, occurrences of 3GC r , TET r , and COT r E. coli and ERY r enterococci in comingled antimicrobial-treated and nonantimicrobial-treated beef cows were not associated with ceftiofur or other antimicrobial use, indicating that other factors influenced the observed levels of antimicrobial-resistant bacteria in feces of beef cows.

  2. Prevalence of antimicrobial resistance in fecal Escherichia coli and Salmonella enterica in Canadian commercial meat, companion, laboratory, and shelter rabbits (Oryctolagus cuniculus) and its association with routine antimicrobial use in commercial meat rabbits.

    PubMed

    Kylie, Jennifer; McEwen, Scott A; Boerlin, Patrick; Reid-Smith, Richard J; Weese, J Scott; Turner, Patricia V

    2017-11-01

    Antimicrobial resistance (AMR) in zoonotic (e.g. Salmonella spp.), pathogenic, and opportunistic (e.g. E. coli) bacteria in animals represents a potential reservoir of antimicrobial resistant bacteria and resistance genes to bacteria infecting humans and other animals. This study evaluated the prevalence of E. coli and Salmonella enterica, and the presence of associated AMR in commercial meat, companion, research, and shelter rabbits in Canada. Associations between antimicrobial usage and prevalence of AMR in bacterial isolates were also examined in commercial meat rabbits. Culture and susceptibility testing was conducted on pooled fecal samples from weanling and adult commercial meat rabbits taken during both summer and winter months (n=100, 27 farms), and from pooled laboratory (n=14, 8 laboratory facilities), companion (n=53), and shelter (n=15, 4 shelters) rabbit fecal samples. At the facility level, E. coli was identified in samples from each commercial rabbit farm, laboratory facility, and 3 of 4 shelters, and in 6 of 53 companion rabbit fecal samples. Seventy-nine of 314 (25.2%; CI: 20.7-30.2%) E. coli isolates demonstrated resistance to >1 antimicrobial agent. At least one E. coli isolate resistant to at least one antimicrobial agent was present in samples from 55.6% of commercial farms, and from 25% of each laboratory and shelter facilities, with resistance to tetracycline being most common; no resistance was identified in companion animal samples. Salmonella enterica subsp. was identified exclusively in pooled fecal samples from commercial rabbit farms; Salmonella enterica serovar London from one farm and Salmonella enterica serovar Kentucky from another. The S. Kentucky isolate was resistant to amoxicillin/clavulanic acid, ampicillin, cefoxitin, ceftiofur, ceftriaxone, streptomycin, and tetracycline, whereas the S. London isolate was pansusceptible. Routine use of antimicrobials on commercial meat rabbit farms was not significantly associated with the

  3. Effects of Menthol Supplementation in Feedlot Cattle Diets on the Fecal Prevalence of Antimicrobial-Resistant Escherichia coli

    PubMed Central

    Aperce, C. C.; Amachawadi, R.; Van Bibber-Krueger, C. L.; Nagaraja, T. G.; Scott, H. M.; Vinasco-Torre, J.; Drouillard, J. S.

    2016-01-01

    The pool of antimicrobial resistance determinants in the environment and in the gut flora of cattle is a serious public health concern. In addition to being a source of human exposure, these bacteria can transfer antibiotic resistance determinants to pathogenic bacteria and endanger the future of antimicrobial therapy. The occurrence of antimicrobial resistance genes on mobile genetic elements, such as plasmids, facilitates spread of resistance. Recent work has shown in vitro anti-plasmid activity of menthol, a plant-based compound with the potential to be used as a feed additive to beneficially alter ruminal fermentation. The present study aimed to determine if menthol supplementation in diets of feedlot cattle decreases the prevalence of multidrug-resistant bacteria in feces. Menthol was included in diets of steers at 0.3% of diet dry matter. Fecal samples were collected weekly for 4 weeks and analyzed for total coliforms counts, antimicrobial susceptibilities, and the prevalence of tet genes in E. coli isolates. Results revealed no effect of menthol supplementation on total coliforms counts or prevalence of E. coli resistant to amoxicillin, ampicillin, azithromycin, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfisoxazole, and sulfamethoxazole; however, 30 days of menthol addition to steer diets increased the prevalence of tetracycline-resistant E. coli (P < 0.02). Although the mechanism by which menthol exerts its effects remains unclear, results of our study suggest that menthol may have an impact on antimicrobial resistance in gut bacteria. PMID:28030622

  4. Impact of antimicrobial use during beef production on fecal occurrence of antimicrobial resistance

    USDA-ARS?s Scientific Manuscript database

    Objective: To determine the impact of typical antimicrobial use during cattle production on fecal occurrence of antimicrobial resistance by culture, quantitative PCR, and metagenomic sequencing. Experimental Design & Analysis: Feces were recovered from colons of 36 lots of "conventional" (CONV) ca...

  5. Feeding of waste milk to Holstein calves affects antimicrobial resistance of Escherichia coli and Pasteurella multocida isolated from fecal and nasal swabs.

    PubMed

    Maynou, G; Bach, A; Terré, M

    2017-04-01

    The use of milk containing antimicrobial residues in calf feeding programs has been shown to select for resistant fecal Escherichia coli in dairy calves. However, information is scarce about the effects of feeding calves waste milk (WM) on the prevalence of multidrug-resistant bacteria. The objective of this study was to determine the antimicrobial resistance patterns of fecal E. coli and nasal Pasteurella multocida isolates from calves fed either milk replacer (MR) or WM in 8 commercial dairy farms (4 farms per feeding program). Fecal and nasal swabs were collected from 20 ± 5 dairy calves at 42 ± 3.2 d of age, and from 10 of these at approximately 1 yr of age in each study farm to isolate the targeted bacteria. Furthermore, resistance of E. coli isolates from calf-environment and from 5 calves at birth and their dams was also evaluated in each study farm. Resistances were tested against the following antimicrobial agents: amoxicillin-clavulanic acid, ceftiofur, colistin, doxycycline (DO), enrofloxacin (ENR), erythromycin, florfenicol, imipenem, and streptomycin. A greater number of fecal E. coli resistant to ENR, florfenicol, and streptomycin and more multidrug-resistant E. coli phenotypes were isolated in feces of calves fed WM than in those fed MR. However, the prevalence of fecal-resistant E. coli was also influenced by calf age, as it increased from birth to 6 wk of age for ENR and DO and decreased from 6 wk to 1 yr of age for DO regardless of the feeding program. From nasal samples, an increase in the prevalence of colistin-resistant P. multocida was observed in calves fed WM compared with those fed MR. The resistance patterns of E. coli isolates from calves and their dams tended to differ, whereas similar resistance profiles among E. coli isolates from farm environment and calves were observed. The findings of this study suggest that feeding calves WM fosters the presence of resistant bacteria in the lower gut and respiratory tracts of dairy calves

  6. First Report on a Randomized Investigation of Antimicrobial Resistance in Fecal Indicator Bacteria from Livestock, Poultry, and Humans in Tanzania.

    PubMed

    Katakweba, Abdul A S; Muhairwa, Amandus P; Lupindu, Athumani M; Damborg, Peter; Rosenkrantz, Jesper T; Minga, Uswege M; Mtambo, Madundo M A; Olsen, John E

    2018-04-01

    This study provides an estimate of antimicrobial resistance in intestinal indicator bacteria from humans (n = 97) and food animals (n = 388) in Tanzania. More than 70% of all fecal samples contained tetracycline (TE), sulfamethoxazole (STX), and ampicillin (AMP)-resistant coliforms, while cefotaxime (CTX)-resistant coliforms were observed in 40% of all samples. The average Log 10 colony forming units/g of CTX-resistant coliforms in samples from humans were 2.20. Of 390 Escherichia coli tested, 66.4% were resistant to TE, 54.9% to STX, 54.9% to streptomycin, and 36.4% to CTX. Isolates were commonly (65.1%) multiresistant. All CTX-resistant isolates contained bla CTX-M gene type. AMP- and vancomycin-resistant enterococci were rare, and the average concentrations in positive samples were low (log 10 0.9 and 0.4, respectively). A low-to-moderate resistance (2.1-15%) was detected in 240 enterococci isolates to the drugs tested, except for rifampicin resistance (75.2% of isolates). The average number of sulII gene copies varied between Log 10 5.37 and 5.68 with no significant difference between sample source, while cattle had significantly higher number of tetW genes than humans. These findings, based on randomly obtained samples, will be instrumental in designing antimicrobial resistance (AMR) intervention strategies for Tanzania.

  7. Patterns of Antimicrobial Resistance Observed in Escherichia coli Isolates Obtained from Domestic- and Wild-Animal Fecal Samples, Human Septage, and Surface Water

    PubMed Central

    Sayah, Raida S.; Kaneene, John B.; Johnson, Yvette; Miller, RoseAnn

    2005-01-01

    A repeated cross-sectional study was conducted to determine the patterns of antimicrobial resistance in 1,286 Escherichia coli strains isolated from human septage, wildlife, domestic animals, farm environments, and surface water in the Red Cedar watershed in Michigan. Isolation and identification of E. coli were done by using enrichment media, selective media, and biochemical tests. Antimicrobial susceptibility testing by the disk diffusion method was conducted for neomycin, gentamicin, streptomycin, chloramphenicol, ofloxacin, trimethoprim-sulfamethoxazole, tetracycline, ampicillin, nalidixic acid, nitrofurantoin, cephalothin, and sulfisoxazole. Resistance to at least one antimicrobial agent was demonstrated in isolates from livestock, companion animals, human septage, wildlife, and surface water. In general, E. coli isolates from domestic species showed resistance to the largest number of antimicrobial agents compared to isolates from human septage, wildlife, and surface water. The agents to which resistance was demonstrated most frequently were tetracycline, cephalothin, sulfisoxazole, and streptomycin. There were similarities in the patterns of resistance in fecal samples and farm environment samples by animal, and the levels of cephalothin-resistant isolates were higher in farm environment samples than in fecal samples. Multidrug resistance was seen in a variety of sources, and the highest levels of multidrug-resistant E. coli were observed for swine fecal samples. The fact that water sample isolates were resistant only to cephalothin may suggest that the resistance patterns for farm environment samples may be more representative of the risk of contamination of surface waters with antimicrobial agent-resistant bacteria. PMID:15746342

  8. Antibiotic-resistant bacteria show widespread collateral sensitivity to antimicrobial peptides.

    PubMed

    Lázár, Viktória; Martins, Ana; Spohn, Réka; Daruka, Lejla; Grézal, Gábor; Fekete, Gergely; Számel, Mónika; Jangir, Pramod K; Kintses, Bálint; Csörgő, Bálint; Nyerges, Ákos; Györkei, Ádám; Kincses, András; Dér, András; Walter, Fruzsina R; Deli, Mária A; Urbán, Edit; Hegedűs, Zsófia; Olajos, Gábor; Méhi, Orsolya; Bálint, Balázs; Nagy, István; Martinek, Tamás A; Papp, Balázs; Pál, Csaba

    2018-06-01

    Antimicrobial peptides are promising alternative antimicrobial agents. However, little is known about whether resistance to small-molecule antibiotics leads to cross-resistance (decreased sensitivity) or collateral sensitivity (increased sensitivity) to antimicrobial peptides. We systematically addressed this question by studying the susceptibilities of a comprehensive set of 60 antibiotic-resistant Escherichia coli strains towards 24 antimicrobial peptides. Strikingly, antibiotic-resistant bacteria show a high frequency of collateral sensitivity to antimicrobial peptides, whereas cross-resistance is relatively rare. We identify clinically relevant multidrug-resistance mutations that increase bacterial sensitivity to antimicrobial peptides. Collateral sensitivity in multidrug-resistant bacteria arises partly through regulatory changes shaping the lipopolysaccharide composition of the bacterial outer membrane. These advances allow the identification of antimicrobial peptide-antibiotic combinations that enhance antibiotic activity against multidrug-resistant bacteria and slow down de novo evolution of resistance. In particular, when co-administered as an adjuvant, the antimicrobial peptide glycine-leucine-amide caused up to 30-fold decrease in the antibiotic resistance level of resistant bacteria. Our work provides guidelines for the development of efficient peptide-based therapies of antibiotic-resistant infections.

  9. Exploring Post-Treatment Reversion of Antimicrobial Resistance in Enteric Bacteria of Food Animals as a Resistance Mitigation Strategy.

    PubMed

    Volkova, Victoriya V; KuKanich, Butch; Riviere, Jim E

    2016-11-01

    Antimicrobial drug use in food animals is associated with an elevation in relative abundance of bacteria resistant to the drug among the animal enteric bacteria. Some of these bacteria are potential foodborne pathogens. Evidence suggests that at least in the enteric nontype-specific Escherichia coli, after treatment the resistance abundance reverts to the background pre-treatment levels, without further interventions. We hypothesize that it is possible to define the distribution of the time period after treatment within which resistance to the administered drug, and possibly other drugs in case of coselection, in fecal bacteria of the treated animals returns to the background pre-treatment levels. Furthermore, it is possible that a novel resistance mitigation strategy for microbiological food safety could be developed based on this resistance reversion phenomenon. The strategy would be conceptually similar to existing antimicrobial drug withdrawal periods, which is a well-established and accepted mitigation strategy for avoiding violative drug residues in the edible products from the treated animals. For developing resistance-relevant withdrawals, a mathematical framework can be used to join the necessary pharmacological, microbiological, and animal production components to project the distributions of the post-treatment resistance reversion periods in the production animal populations for major antimicrobial drug classes in use. The framework can also help guide design of empirical studies into the resistance-relevant withdrawal periods and development of mitigation approaches to reduce the treatment-associated elevation of resistance in animal enteric bacteria. We outline this framework, schematically and through exemplar equations, and how its components could be formulated.

  10. Diversity of fecal coliforms and their antimicrobial resistance patterns in wastewater treatment model plant.

    PubMed

    Luczkiewicz, A; Fudala-Ksiazek, S; Jankowska, K; Quant, B; Olańczuk-Neyman, K

    2010-01-01

    The occurrence of resistance patterns among wastewater fecal coliforms was determined in the study. Susceptibility of the isolates was tested against 19 antimicrobial agents: aminoglycosides, aztreonam, carbapenems, cephalosporines, beta-lactam/beta-lactamase inhibitors, penicillines, tetracycline, trimethoprim/sulfamethoxazole, and fluoroquinolones. Additionally the removal of resistant isolates was evaluated in the laboratory-scale wastewater treatment model plant (M-WWTP), continuously supplied with the wastewater obtained from the full-scale WWTP. Number of fecal coliforms in raw (after mechanical treatment) and treated wastewater, as well as in aerobic chamber effluent was determined using selective medium. The selected strains were identified and examined for antibiotic resistance using Phoenix Automated Microbiology System (BD Biosciences, USA). The strains were identified as Escherichia coli (n=222), Klebsiella pneumoniae ssp. ozaenae (n=9), and Pantoea agglomerans (n=1). The isolate of P. agglomerans as well as 48% of E. coli isolates were sensitive to all antimicrobials tested. The most frequent resistance patterns were found for ampicillin: 100% of K. pneumoniae ssp. ozaenae and 41% of E. coli isolates. Among E. coli isolates 12% was regarded as multiple antimicrobial resistant (MAR). In the studied M-WWTP, the applied activated sludge processes reduced considerably the number of fecal coliforms, but increased the ratio of antimicrobial-resistant E. coli isolates to sensitive ones, especially among strains with MAR patterns.

  11. New York City House Mice (Mus musculus) as Potential Reservoirs for Pathogenic Bacteria and Antimicrobial Resistance Determinants.

    PubMed

    Williams, Simon H; Che, Xiaoyu; Paulick, Ashley; Guo, Cheng; Lee, Bohyun; Muller, Dorothy; Uhlemann, Anne-Catrin; Lowy, Franklin D; Corrigan, Robert M; Lipkin, W Ian

    2018-04-17

    House mice ( Mus musculus ) thrive in large urban centers worldwide. Nonetheless, little is known about the role that they may play in contributing to environmental contamination with potentially pathogenic bacteria. Here, we describe the fecal microbiome of house mice with emphasis on detection of pathogenic bacteria and antimicrobial resistance genes by molecular methods. Four hundred sixteen mice were collected from predominantly residential buildings in seven sites across New York City over a period of 13 months. 16S rRNA sequencing identified Bacteroidetes as dominant and revealed high levels of Proteobacteria A targeted PCR screen of 11 bacteria, as indicated by 16S rRNA analyses, found that mice are carriers of several gastrointestinal disease-causing agents, including Shigella , Salmonella , Clostridium difficile , and diarrheagenic Escherichia coli Furthermore, genes mediating antimicrobial resistance to fluoroquinolones ( qnrB ) and β-lactam drugs ( bla SHV and bla ACT/MIR ) were widely distributed. Culture and molecular strain typing of C. difficile revealed that mice harbor ribotypes associated with human disease, and screening of kidney samples demonstrated genetic evidence of pathogenic Leptospira species. In concert, these findings support the need for further research into the role of house mice as potential reservoirs for human pathogens and antimicrobial resistance in the built environment. IMPORTANCE Mice are commensal pests often found in close proximity to humans, especially in urban centers. We surveyed mice from seven sites across New York City and found multiple pathogenic bacteria associated with febrile and gastrointestinal disease as well as an array of antimicrobial resistance genes. Copyright © 2018 Williams et al.

  12. New York City House Mice (Mus musculus) as Potential Reservoirs for Pathogenic Bacteria and Antimicrobial Resistance Determinants

    PubMed Central

    Williams, Simon H.; Che, Xiaoyu; Paulick, Ashley; Guo, Cheng; Lee, Bohyun; Muller, Dorothy; Uhlemann, Anne-Catrin; Lowy, Franklin D.; Corrigan, Robert M.

    2018-01-01

    ABSTRACT House mice (Mus musculus) thrive in large urban centers worldwide. Nonetheless, little is known about the role that they may play in contributing to environmental contamination with potentially pathogenic bacteria. Here, we describe the fecal microbiome of house mice with emphasis on detection of pathogenic bacteria and antimicrobial resistance genes by molecular methods. Four hundred sixteen mice were collected from predominantly residential buildings in seven sites across New York City over a period of 13 months. 16S rRNA sequencing identified Bacteroidetes as dominant and revealed high levels of Proteobacteria. A targeted PCR screen of 11 bacteria, as indicated by 16S rRNA analyses, found that mice are carriers of several gastrointestinal disease-causing agents, including Shigella, Salmonella, Clostridium difficile, and diarrheagenic Escherichia coli. Furthermore, genes mediating antimicrobial resistance to fluoroquinolones (qnrB) and β-lactam drugs (blaSHV and blaACT/MIR) were widely distributed. Culture and molecular strain typing of C. difficile revealed that mice harbor ribotypes associated with human disease, and screening of kidney samples demonstrated genetic evidence of pathogenic Leptospira species. In concert, these findings support the need for further research into the role of house mice as potential reservoirs for human pathogens and antimicrobial resistance in the built environment. PMID:29666289

  13. Bacteria from Animals as a Pool of Antimicrobial Resistance Genes

    PubMed Central

    Argudín, Maria Angeles; Deplano, Ariane; Meghraoui, Alaeddine; Dodémont, Magali; Heinrichs, Amelie; Denis, Olivier; Nonhoff, Claire; Roisin, Sandrine

    2017-01-01

    Antimicrobial agents are used in both veterinary and human medicine. The intensive use of antimicrobials in animals may promote the fixation of antimicrobial resistance genes in bacteria, which may be zoonotic or capable to transfer these genes to human-adapted pathogens or to human gut microbiota via direct contact, food or the environment. This review summarizes the current knowledge of the use of antimicrobial agents in animal health and explores the role of bacteria from animals as a pool of antimicrobial resistance genes for human bacteria. This review focused in relevant examples within the ESC(K)APE (Enterococcus faecium, Staphylococcus aureus, Clostridium difficile (Klebsiella pneumoniae), Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae) group of bacterial pathogens that are the leading cause of nosocomial infections throughout the world. PMID:28587316

  14. Antimicrobial-resistant bacteria in wild game in Slovenia

    NASA Astrophysics Data System (ADS)

    Križman, M.; Kirbiš, A.; Jamnikar-Ciglenečki, U.

    2017-09-01

    Wildlife is usually not exposed to clinically-used antimicrobial agents but can acquire antimicrobial resistance throughout contact with humans, domesticated animals and environments. Samples of faeces from intestines (80 in total) were collected from roe deer (52), wild boars (11), chamois (10) red deer (6) and moufflon (1). After culture on ChromID extended spectrum β-lactamase (ESBL) plates to select for growth of ESBL-producing bacteria, 25 samples produced bacterial colonies for further study. Six species of bacteria were identified from the 25 samples: Stenotrophomonas maltophilia, Serratia fonticola, Stenotrophomonas nitritireducens, Enterococcus faecium, Enterococcus faecalis and Escherichia coli. Two ESBL enzymes were amplified from group TEM and three from group CTX-M-1. Undercooked game meat and salami can be a source of resistant bacteria when animals are not eviscerated properly.

  15. Effects of tetracycline on antibiotic resistance and removal of fecal indicator bacteria in aerated and unaerated leachfield mesocosms.

    PubMed

    Atoyan, Janet A; Patenaude, Erika L; Potts, David A; Amador, José A

    2007-09-01

    Antibiotics can be present in low concentrations in domestic wastewater, but little is known about their effect on bacteria in onsite wastewater treatment systems. Mesocosms, consisting of soil-filled lysimeters representing the leachfield of a septic system under aerated (AIR) and unaerated (LEACH) conditions, were used to study the effects of tetracycline addition (5 mg L(-1)) to septic tank effluent on tetracycline resistance in the fecal indicator bacteria Escherichia coli and fecal streptococci, and on their removal. The mesocosms were dosed with antibiotic for 10 days, and effects monitored for 52 days. The fraction of resistant bacteria in mesocosm drainage water relative to that in septic tank effluent, GammaRes, for E. coli ranged from 0 to 0.66 in the AIR treatment and from 0 to 3.32 in the LEACH treatment. For fecal streptococci, GammaRes ranged from 0 to 0.41 and from 0.63 to 1.06 in the AIR and LEACH treatments, respectively. No significant differences in antibiotic resistance of fecal indicator bacteria were observed among sampling dates in soil or water from either treatment. Tetracycline had no significant effect on removal of fecal indicator bacteria, which ranged from 99.9 to 100% for E. coli and from 95.9 to 100% for fecal streptococci. Our results suggest that short-term addition of tetracycline at environmentally-relevant concentrations is likely to have minimal consequences on pathogen removal from wastewater and development of antibiotic resistance among pathogenic bacteria in leachfield soil.

  16. Intrinsic, adaptive and acquired antimicrobial resistance in Gram-negative bacteria.

    PubMed

    Arzanlou, Mohsen; Chai, Wern Chern; Venter, Henrietta

    2017-02-28

    Gram-negative bacteria are responsible for a large proportion of antimicrobial-resistant infections in humans and animals. Among this class of bacteria are also some of the most successful environmental organisms. Part of this success is their adaptability to a variety of different niches, their intrinsic resistance to antimicrobial drugs and their ability to rapidly acquire resistance mechanisms. These mechanisms of resistance are not exclusive and the interplay of several mechanisms causes high levels of resistance. In this review, we explore the molecular mechanisms underlying resistance in Gram-negative organisms and how these different mechanisms enable them to survive many different stress conditions. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  17. Role of shellfish hatchery as a reservoir of antimicrobial resistant bacteria.

    PubMed

    Miranda, Claudio D; Rojas, Rodrigo; Garrido, Marcela; Geisse, Julieta; González, Gerardo

    2013-09-15

    The main aim of this study was to determine the occurrence of resistant bacteria in florfenicol-treated and untreated scallop larval cultures from a commercial hatchery and to characterize some selected florfenicol-resistant strains. Larval cultures from untreated and treated rearing tanks exhibited percentages of copiotrophic bacteria resistant to florfenicol ranging from 0.03% to 10.67% and 0.49-18.34%, respectively, whereas florfenicol resistance among oligotrophic bacteria varied from 1.44% to 35.50% and 3.62-95.71%, from untreated and treated larvae, respectively. Florfenicol resistant microbiota from reared scallop larvae mainly belonged to the Pseudomonas and Pseudoalteromonas genus and were mainly resistant to florfenicol, chloramphenicol, streptomycin and co-trimoxazole. This is the first study reporting antimicrobial resistant bacteria associated to a shellfish hatchery and the results suggest that a continuous surveillance of antimicrobial resistance even in absence of antibacterial therapy is urgently required to evaluate potential undesirable consequences on the surrounding environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Mechanisms of Antimicrobial Peptide Resistance in Gram-Negative Bacteria

    PubMed Central

    Band, Victor I.; Weiss, David S.

    2014-01-01

    Cationic antimicrobial peptides (CAMPs) are important innate immune defenses that inhibit colonization by pathogens and contribute to clearance of infections. Gram-negative bacterial pathogens are a major target, yet many of them have evolved mechanisms to resist these antimicrobials. These resistance mechanisms can be critical contributors to bacterial virulence and are often crucial for survival within the host. Here, we summarize methods used by Gram-negative bacteria to resist CAMPs. Understanding these mechanisms may lead to new therapeutic strategies against pathogens with extensive CAMP resistance. PMID:25927010

  19. Antimicrobial resistance of zoonotic and commensal bacteria in Europe: the missing link between consumption and resistance in veterinary medicine.

    PubMed

    Garcia-Migura, Lourdes; Hendriksen, Rene S; Fraile, Lorenzo; Aarestrup, Frank M

    2014-05-14

    The emergence of resistance in food animals has been associated to the consumption of antimicrobials in veterinary medicine. Consequently, monitoring programs have been designed to monitor the occurrence of antimicrobial resistant bacteria. This study analyses the amount of antimicrobial agents used in nine European countries from 2005 to 2011, and compares by univariate analysis the correlations between consumptions of each of the following antimicrobial classes; tetracycline, penicillins, cephalosporins, quinolones and macrolides. An overview of resistance in zoonotic and commensal bacteria in Europe focusing on Salmonella, Escherichia coli, Campylobacter sp. and Enterococcus sp., during the same period of time based on monitoring programs is also assessed. With the exception of cephalosporins, linear regressions showed strong positive associations between the consumption of the four different antimicrobial classes. Substantial differences between countries were observed in the amount of antimicrobials used to produce 1 kg of meat. Moreover, large variations in proportions of resistant bacteria were reported by the different countries, suggesting differences in veterinary practice. Despite the withdrawn of a specific antimicrobial from "on farm" use, persistence over the years of bacteria resistant to this particular antimicrobial agent, was still observed. There were also differences in trends of resistance associated to specific animal species. In order to correlate the use of antimicrobial agents to the presence of resistance, surveillance of antimicrobial consumption by animal species should be established. Subsequently, intervention strategies could be designed to minimize the occurrence of resistance. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Analysis of antimicrobial resistance mechanisms in MDR bacteria by microarray and high-throughput sequencing

    USDA-ARS?s Scientific Manuscript database

    Antimicrobial resistance in pathogenic bacteria is a major concern in human and animal health. The National Antimicrobial Resistance Monitoring System (NARMS) was designed by the CDC, FDA, and USDA to monitor antimicrobial resistance in the U.S. The Bacterial Epidemiology and Antimicrobial Resistanc...

  1. Antimicrobial Resistance and Resistance Genes in Aerobic Bacteria Isolated from Pork at Slaughter.

    PubMed

    Li, Lili; Heidemann Olsen, Rikke; Ye, Lei; Yan, He; Nie, Qing; Meng, Hecheng; Shi, Lei

    2016-04-01

    The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram-negative bacteria (92.2%) and gram-positive bacteria (7.8%). High levels of resistance were detected to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin (36.2 to 54.3%), and lower levels were detected to nitrofurantoin, cefotaxime, gentamicin, ciprofloxacin, and chloramphenicol (7.8 to 29.2%). Across species, genes conferring antimicrobial resistance were observed with the following frequencies: blaTEM, 40.7%; blaCMY-2, 15.2%; blaCTX-M, 11.5%; sul2, 27.2%; sul1, 14.4%; tet(A), 5.4%; tet(L), 5.4%; tet(M), 5.0%; tet(E), 3.7%; tet(C), 3.3%; tet(S), 2.5%; and tet(K), 0.8%. Various antimicrobial resistance genes were found in new carriers: blaTEM in Lactococcus garvieae, Myroides odoratimimus, Aeromonas hydrophila, Staphylococcus sciuri, Raoultella terrigena, Macrococcus caseolyticus, Acinetobacter ursingii, Sphingobacterium sp., and Oceanobacillus sp.; blaCMY-2 in Lactococcus lactis, Klebsiella oxytoca, Serratia marcescens, Acinetobacter baumannii, and Myroides phaeus; tet(L) in M. caseolyticus; sul1 in Vibrio cincinnatiensis; sul2 in Acinetobacter bereziniae, Acinetobacter johnsonii, and V. cincinnatiensis; and the class 1 integron and gene cassette aadA2 in V. cincinnatiensis. Approximately 6.6% of isolates contained class 1 integrons, and one isolate harbored class 2 integrons. Plasmid associated intI1 and androgen receptor- encoding genes were transferred into Escherichia coli J53 and E. coli DH5α by conjugation and transformation experiments, respectively. Our study highlights the importance of aerobic bacteria from pork as reservoirs for antimicrobial resistance genes and mobile genetic elements that can readily be transferred intra- and interspecies.

  2. Antimicrobial Use for and Resistance of Zoonotic Bacteria Recovered from Nonhuman Primates.

    PubMed

    Kim, Jeffrey; Coble, Dondrae J; Salyards, Gregory W; Bower, Julie K; Rinaldi, William J; Plauche, Gail B; Habing, Gregory G

    2017-02-01

    As a growing threat to human and animal health, antimicrobial resistance (AMR) has become a central public-health topic. Largescale surveillance systems, such as the National Antimicrobial Resistance Monitoring System (NARMS), are now established to monitor and provide guidance regarding AMR, but comprehensive literature on AMR among NHP is sparse. This study provides data regarding current antimicrobial use strategies and the prevalence of AMR in zoonotic bacteria recovered from NHP within biomedical research institutions. We focused on 4 enteric bacteria: Shigella flexneri, Yersinia enterocolitica, Y. pseudotuberculosis, and Campylobacter jejuni. Fifteen veterinarians, 7 biomedical research institutions, and 4 diagnostic laboratories participated, providing susceptibility test results from January 2012 through April 2015. Veterinarians primarily treated cases caused by S. flexneri, Y. enterocolitica, and Y. pseudotuberculosis with enrofloxacin but treated C. jejuni cases with azithromycin and tylosin. All isolates were susceptible to the associated primary antimicrobial but often showed resistance to others. Specifically, S. flexneri isolates frequently were resistant to erythromycin (87.5%), doxycycline (73.7%), and tetracycline (38.3%); Y. enterocolitica isolates to ampicillin (100%) and cefazolin (93.6%); and C. jejuni isolates to methicillin (99.5%) and cephalothin (97.5%). None of the 58 Y. pseudotuber-culosis isolates was resistant to any tested antimicrobial. Notably, resistance patterns were not shared between this study's NHP isolates and human isolates presented by NARMS. Our findings indicate that zoonotic bacteria from NHP diagnostic samples are broadly susceptible to the antimicrobials used to treat the clinical infections. These results can help veterinarians ensure effective antimicrobial therapy and protect staff by minimizing occupational risk.

  3. Antimicrobial Use for and Resistance of Zoonotic Bacteria Recovered from Nonhuman Primates

    PubMed Central

    Kim, Jeffrey; Coble, Dondrae J; Salyards, Gregory W; Bower, Julie K; Rinaldi, William J; Plauche, Gail B; Habing, Gregory G

    2017-01-01

    As a growing threat to human and animal health, antimicrobial resistance (AMR) has become a central public-health topic. Large-scale surveillance systems, such as the National Antimicrobial Resistance Monitoring System (NARMS), are now established to monitor and provide guidance regarding AMR, but comprehensive literature on AMR among NHP is sparse. This study provides data regarding current antimicrobial use strategies and the prevalence of AMR in zoonotic bacteria recovered from NHP within biomedical research institutions. We focused on 4 enteric bacteria: Shigella flexneri, Yersinia enterocolitica, Y. pseudotuberculosis, and Campylobacter jejuni. Fifteen veterinarians, 7 biomedical research institutions, and 4 diagnostic laboratories participated, providing susceptibility test results from January 2012 through April 2015. Veterinarians primarily treated cases caused by S. flexneri, Y. enterocolitica, and Y. pseudotuberculosis with enrofloxacin but treated C. jejuni cases with azithromycin and tylosin. All isolates were susceptible to the associated primary antimicrobial but often showed resistance to others. Specifically, S. flexneri isolates frequently were resistant to erythromycin (87.5%), doxycycline (73.7%), and tetracycline (38.3%); Y. enterocolitica isolates to ampicillin (100%) and cefazolin (93.6%); and C. jejuni isolates to methicillin (99.5%) and cephalothin (97.5%). None of the 58 Y. pseudotuberculosis isolates was resistant to any tested antimicrobial. Notably, resistance patterns were not shared between this study's NHP isolates and human isolates presented by NARMS. Our findings indicate that zoonotic bacteria from NHP diagnostic samples are broadly susceptible to the antimicrobials used to treat the clinical infections. These results can help veterinarians ensure effective antimicrobial therapy and protect staff by minimizing occupational risk. PMID:28222842

  4. Monitoring of antimicrobial resistance in pathogenic bacteria from livestock animals.

    PubMed

    Wallmann, Jürgen

    2006-06-01

    Facing the problem of development and spreading of bacterial resistance, preventive strategies are considered the most appropriate means to counteract. The establishment of corresponding management options relies on scientifically defensible efforts to obtain objective data on the prevalence of bacterial resistance in healthy and diseased livestock. Additionally, detailed statistics are needed on the overall amount of antimicrobial agents dispensed in Germany. The collection of valid data on the prevalence of resistance requires representative and cross-sectional studies. The German national antimicrobial resistance monitoring of the Federal Office of Consumer Protection and Food Safety (BVL) determines the current quantitative resistance level of life-stock pathogens, in order to permit the evaluation and surveillance of the distribution of resistances on a valid basis. Essential key features determining the design of these studies comprise (1) a statistically valid sampling program. This incorporates regional differences in animal population density, (2) the avoidance of "copy strains", (3) testing of no more than two bacterial strains belonging to one species per herd, (4) testing only if no antimicrobial therapy preceded sample collection, and (5) the use of standardized methods [e.g. microdilution broth method to determine the minimal inhibitory concentration (MIC)]. The analysis and interpretation of this data permits reliable identification and definition of epidemiological characteristics of resistance and its development in animal associated bacteria, such as geographically and time wise differentiated profiles on its prevalence, the emergence of unknown phenotypes of resistance and an assessment of the threat resistant bacteria from animals pose for humans. In applied antimicrobial therapy, the data can serve as a decision guidance in choosing the antimicrobial agent most adapted to the prevailing epidemiological situation. The susceptibility testing

  5. Public health significance of antimicrobial-resistant gram-negative bacteria in raw bulk tank milk.

    PubMed

    Straley, B A; Donaldson, S C; Hedge, N V; Sawant, A A; Srinivasan, V; Oliver, S P; Jayarao, B M

    2006-01-01

    The dairy farm environment and animals on the farm serve as important reservoirs of pathogenic and commensal bacteria that could potentially gain access to milk in the bulk tank via several pathways. Pathogenic gram-negative bacteria can gain access to bulk tank milk from infected mammary glands, contaminated udders and milking machines, and/or from the dairy farm environment. Contaminated raw milk when consumed by humans or fed to animals on the farm can result in gastroenteric infections in humans and animals and also provide an opportunity for organisms to colonize the farm environment. This scenario becomes much more complicated when pathogenic bacteria such as Salmonella, Shiga toxin-producing Escherichia coli, and commensal gram-negative enteric bacteria encode for antimicrobial resistance determinants. In recent years, the role of commensal bacteria as reservoirs of genetic determinants for antimicrobial resistance has come under closer scrutiny. Commensal bacteria in bulk tank milk can be a significant reservoir of antimicrobial determinants. Raw milk consumption can result in exposure to antimicrobial-resistant commensal gram-negative bacteria. This paper examines the prevalence and role of commensal gram-negative enteric bacteria in bulk tank milk and their public health significance.

  6. Antimicrobial resistance, heavy metal resistance and integron content in bacteria isolated from a South African tilapia aquaculture system.

    PubMed

    Chenia, Hafizah Y; Jacobs, Anelet

    2017-11-21

    Antibacterial compounds and metals co-select for antimicrobial resistance when bacteria harbour resistance genes towards both types of compounds, facilitating the proliferation and evolution of antimicrobial and heavy metal resistance. Antimicrobial and heavy metal resistance indices of 42 Gram-negative bacteria from a tilapia aquaculture system were determined to identify possible correlations between these phenotypes. Agar dilution assays were carried out to determine susceptibility to cadmium, copper, lead, mercury, chromate and zinc, while susceptibility to 21 antimicrobial agents was investigated by disk diffusion assays. Presence of merA, the mercury resistance gene, was determined by dot-blot hybridizations and PCR. Association of mercury resistance with integrons and transposon Tn21 was also investigated by PCR. Isolates displayed a high frequency of antimicrobial (erythromycin: 100%; ampicillin: 85%; trimethoprim: 78%) and heavy metal (Zn2+: 95%; Cd2+: 91%) resistance. No correlation was established between heavy metal and multiple antibiotic resistance indices. Significant positive correlations were observed between heavy metal resistance profiles, indices, Cu2+ and Cr3+ resistance with erythromycin resistance. Significant positive correlations were observed between merA (24%)/Tn21 (24%) presence and heavy metal resistance profiles and indices; however, significant negative correlations were obtained between integron-associated qacE∆1 (43%) and sulI (26%) gene presence and heavy metal resistance indices. Heavy metal and antimicrobial agents co-select for resistance, with fish-associated, resistant bacteria demonstrating simultaneous heavy metal resistance. Thus, care should be taken when using anti-fouling heavy metals as feed additives in aquaculture facilities.

  7. Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria.

    PubMed

    Marinho, Palloma Rodrigues; Moreira, Ana Paula Barbosa; Pellegrino, Flávia Lúcia Piffano Costa; Muricy, Guilherme; Bastos, Maria do Carmo de Freire; Santos, Kátia Regina Netto dos; Giambiagi-deMarval, Marcia; Laport, Marinella Silva

    2009-08-01

    Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3) isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

  8. Occurrence of antimicrobial agents, drug-resistant bacteria, and genes in the sewage-impacted Vistula River (Poland).

    PubMed

    Giebułtowicz, Joanna; Tyski, Stefan; Wolinowska, Renata; Grzybowska, Wanda; Zaręba, Tomasz; Drobniewska, Agata; Wroczyński, Piotr; Nałęcz-Jawecki, Grzegorz

    2018-02-01

    Antimicrobial agents (antimicrobials) are a group of therapeutic and hygienic agents that either kill microorganisms or inhibit their growth. Their occurrence in surface water may reveal harmful effects on aquatic biota and challenge microbial populations. Recently, there is a growing concern over the contamination of surface water with both antimicrobial agents and multidrug-resistant bacteria. The aim of the study was the determination of the presence of selected antimicrobials at specific locations of the Vistula River (Poland), as well as in tap water samples originating from the Warsaw region. Analysis was performed using the liquid chromatography-electrospray ionization-tandem mass spectrometry method. In addition, the occurrence of drug-resistant bacteria and resistance genes was determined using standard procedures. This 2-year study is the first investigation of the simultaneous presence of antimicrobial agents, drug-resistant bacteria, and genes in Polish surface water. In Poland, relatively high concentrations of macrolides are observed in both surface and tap water. Simultaneous to the high macrolide levels in the environment, the presence of the erm B gene, coding the resistance to macrolides, lincosamides, and streptogramin, was detected in almost all sampling sites. Another ubiquitous gene was int1, an element of the 5'-conserved segment of class 1 integrons that encode site-specific integrase. Also, resistant isolates of Enterococcus faecium and Enterococcus faecalis and Gram-negative bacteria were recovered. Multidrug-resistant bacteria isolates of Gram-negative and Enterococcus were also detected. The results show that wastewater treatment plants (WWTP) are the main source of most antimicrobials, resistant bacteria, and genes in the aquatic environment, probably due to partial purification during wastewater treatment processes.

  9. The fecal bacteria

    USGS Publications Warehouse

    Sadowsky, Michael J.; Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  10. Presence of antimicrobial resistance in coliform bacteria from hatching broiler eggs with emphasis on ESBL/AmpC-producing bacteria.

    PubMed

    Mezhoud, H; Chantziaras, I; Iguer-Ouada, M; Moula, N; Garmyn, A; Martel, A; Touati, A; Smet, A; Haesebrouck, F; Boyen, F

    2016-08-01

    Antimicrobial resistance is recognized as one of the most important global health challenges. Broilers are an important reservoir of antimicrobial resistant bacteria in general and, more particularly, extended-spectrum β-lactamases (ESBL)/AmpC-producing Enterobacteriaceae. Since contamination of 1-day-old chicks is a potential risk factor for the introduction of antimicrobial resistant Enterobacteriaceae in the broiler production chain, the presence of antimicrobial resistant coliform bacteria in broiler hatching eggs was explored in the present study. Samples from 186 hatching eggs, collected from 11 broiler breeder farms, were inoculated on MacConkey agar with or without ceftiofur and investigated for the presence of antimicrobial resistant lactose-positive Enterobacteriaceae, particularly, ESBL/AmpC-producers. Escherichia coli and Enterobacter cloacae were obtained from the eggshells in 10 out of 11 (10/11) sampled farms. The majority of the isolates were recovered from crushed eggshells after external decontamination suggesting that these bacteria are concealed from the disinfectants in the egg shell pores. Antimicrobial resistance testing revealed that approximately 30% of the isolates showed resistance to ampicillin, tetracycline, trimethoprim and sulphonamides, while the majority of isolates were susceptible to amoxicillin-clavulanic acid, nitrofurantoin, aminoglycosides, florfenicol, neomycin and apramycin. Resistance to extended-spectrum cephalosporins was detected in eight Enterobacteriaceae isolates from five different broiler breeder farms. The ESBL phenotype was confirmed by the double disk synergy test and blaSHV-12, blaTEM-52 and blaACT-39 resistance genes were detected by PCR. This report is the first to present broiler hatching eggs as carriers and a potential source of ESBL/AmpC-producing Enterobacteriaceae for broiler chicks.

  11. Characterization of antimicrobial resistance and quinolone resistance factors in high-level ciprofloxacin-resistant Enterococcus faecalis and Enterococcus faecium isolates obtained from fresh produce and fecal samples of patients.

    PubMed

    Kim, Min-Chan; Woo, Gun-Jo

    2017-07-01

    The emergence of fluoroquinolone-resistant enterococci is worldwide. Antimicrobial resistance was characterized and the effect of quinolone-resistance factors was analyzed in high-level ciprofloxacin-resistant (HLCR) Enterococcus faecalis and Enterococcus faecium isolated from fresh produce and fecal samples of patients. Among the 81 ciprofloxacin-resistant Enterococcus isolates, 46 showed high levels of ciprofloxacin resistance, resistance to other quinolone antibiotics, and multidrug resistance profiles. The virulence factors esp and hyl were identified in 27 (58.7%) and 25 (54.3%) of isolates, respectively. Sequence type analysis showed that 35 strains of HLCR E. faecium were clonal complex 17. Eleven strains of HLCR E. faecalis were confirmed as sequence type (ST) 28, ST 64 and ST 125. Quinolone resistance-determining region mutation was identified in HLCR Enterococcus isolates; with serine being changed in gyrA83, gyrA87 and parC80. This result shows that gyrA and parC mutations could be important factors for high-level resistance to fluoroquinolones. No significant differences were observed in antimicrobial resistance patterns and genetic characteristics among the isolates from fresh produce and fecal samples. Therefore, good agricultural practices in farming and continuous monitoring of patients, food and the environment for Enterococcus spp. should be performed to prevent antimicrobial resistance and enable reduction of resistance rates. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  12. Development and transmission of antimicrobial resistance among Gram-negative bacteria in animals and their public health impact.

    PubMed

    Mukerji, Shewli; O'Dea, Mark; Barton, Mary; Kirkwood, Roy; Lee, Terence; Abraham, Sam

    2017-02-28

    Gram-negative bacteria are known to cause severe infections in both humans and animals. Antimicrobial resistance (AMR) in Gram-negative bacteria is a major challenge in the treatment of clinical infections globally due to the propensity of these organisms to rapidly develop resistance against antimicrobials in use. In addition, Gram-negative bacteria possess highly efficient mechanisms through which the AMR can be disseminated between pathogenic and commensal bacteria of the same or different species. These unique traits of Gram-negative bacteria have resulted in evolution of Gram-negative bacterial strains demonstrating resistance to multiple classes of antimicrobials. The evergrowing resistance issue has not only resulted in limitation of treatment options but also led to increased treatment costs and mortality rates in humans and animals. With few or no new antimicrobials in production to combat severe life-threatening infections, AMR has been described as the one of the most severe, long-term threats to human health. Aside from overuse and misuse of antimicrobials in humans, another factor that has exacerbated the emergence of AMR in Gram-negative bacteria is the veterinary use of antimicrobials that belong to the same classes considered to be critically important for treating serious life-threatening infections in humans. Despite the fact that development of AMR dates back to before the introduction of antimicrobials, the recent surge in the resistance towards all available critically important antimicrobials has emerged as a major public health issue. This review thus focuses on discussing the development, transmission and public health impact of AMR in Gram-negative bacteria in animals. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  13. Classification of Antibiotic Resistance Patterns of Indicator Bacteria by Discriminant Analysis: Use in Predicting the Source of Fecal Contamination in Subtropical Waters

    PubMed Central

    Harwood, Valerie J.; Whitlock, John; Withington, Victoria

    2000-01-01

    The antibiotic resistance patterns of fecal streptococci and fecal coliforms isolated from domestic wastewater and animal feces were determined using a battery of antibiotics (amoxicillin, ampicillin, cephalothin, chlortetracycline, oxytetracycline, tetracycline, erythromycin, streptomycin, and vancomycin) at four concentrations each. The sources of animal feces included wild birds, cattle, chickens, dogs, pigs, and raccoons. Antibiotic resistance patterns of fecal streptococci and fecal coliforms from known sources were grouped into two separate databases, and discriminant analysis of these patterns was used to establish the relationship between the antibiotic resistance patterns and the bacterial source. The fecal streptococcus and fecal coliform databases classified isolates from known sources with similar accuracies. The average rate of correct classification for the fecal streptococcus database was 62.3%, and that for the fecal coliform database was 63.9%. The sources of fecal streptococci and fecal coliforms isolated from surface waters were identified by discriminant analysis of their antibiotic resistance patterns. Both databases identified the source of indicator bacteria isolated from surface waters directly impacted by septic tank discharges as human. At sample sites selected for relatively low anthropogenic impact, the dominant sources of indicator bacteria were identified as various animals. The antibiotic resistance analysis technique promises to be a useful tool in assessing sources of fecal contamination in subtropical waters, such as those in Florida. PMID:10966379

  14. Antimicrobial resistance in Gram-positive bacteria from Timorese River Buffalo (Bubalus bubalis) skin microbiota.

    PubMed

    Oliveira, Manuela; Monteiro, José L; Rana, Sílvia; Vilela, Cristina L

    2010-06-01

    The Timorese River Buffalo (Bubalus bubalis) plays a major role in the East Timor economy, as it is an important source of animal protein in human nutrition. They are widely spread throughout the country and are in direct contact with the populations. In spite of this proximity, information on their microbiota is scarce. This work aimed at characterizing the skin microbiota of the East Timorese River Buffalo and its antimicrobial resistance profile. Skin swab samples were taken from 46 animals in surveys conducted in three farms located in "Suco de Nairete", Lospalos district, during July and August 2006. Bacteria were isolated and identified according to conventional microbiological procedures. A total of 456 isolates were obtained, including Gram-positive (n = 243) and Gram-negative (n = 213) bacteria. Due to their importance as potential pathogens and as vehicles for antimicrobial resistance transmission, Gram-positive cocci (n = 27) and bacilli (n = 77) isolates were further characterized, and their antimicrobial resistance profile determined by the disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. This study shows the high bacterial diversity of B. bubalis skin microbiota, representing an important first step towards understanding its importance and epidemiologic role in animal health. It also points out the potential role of these animals as vectors of antimicrobial resistant bacteria dissemination and the importance of antimicrobial resistance monitoring in developing countries.

  15. Effects of feeding pasteurized waste milk to dairy calves on phenotypes and genotypes of antimicrobial resistance in fecal Escherichia coli isolates before and after weaning.

    PubMed

    Maynou, G; Migura-Garcia, L; Chester-Jones, H; Ziegler, D; Bach, A; Terré, M

    2017-10-01

    The aim of this study was to evaluate the effects of feeding pasteurized waste milk (pWM) to calves on antimicrobial resistance of fecal Escherichia coli at both phenotypic and genotypic levels. Fifty-two Holstein female calves (3 ± 1.3 d of age) were fed 1 of the 2 different types of milk: milk replacer (MR) without antimicrobials or pWM with β-lactam residues until weaning at 49 d of age. Fecal swabs of all calves were obtained on d 0, 35, and 56 of the study and 3 E. coli isolates per sample were studied. Phenotypic resistance was tested by the disk diffusion method against a panel of 12 antimicrobials. A total of 13 resistance genes consisting of β-lactam, sulfonamide, tetracycline, and aminoglycoside families were examined by PCR. Feeding pWM to calves increased the presence of phenotypic resistance to ampicillin, cephalotin, ceftiofur, and florfenicol in fecal E. coli compared with MR-fed calves. However, the presence of resistance to sulfonamides, tetracyclines, and aminoglycosides was common in dairy calves independent of their milk-feeding source, suggesting other factors apart from the feeding source are involved in the emergence of antimicrobial resistance. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Antibiotic-resistant fecal bacteria, antibiotics, and mercury in surface waters of Oakland County, Michigan, 2005-2006

    USGS Publications Warehouse

    Fogarty, Lisa R.; Duris, Joseph W.; Crowley, Suzanne L.; Hardigan, Nicole

    2007-01-01

    Water samples collected from 20 stream sites in Oakland and Macomb Counties, Mich., were analyzed to learn more about the occurrence of cephalosporin-resistant Escherichia coli (E. coli) and vancomycin-resistant enterococci (VRE) and the co-occurrence of antibiotics and mercury in area streams. Fecal indicator bacteria concentrations exceeded the Michigan recreational water-quality standard of 300 E. coli colony forming units (CFU) per 100 milliliters of water in 19 of 35 stream-water samples collected in Oakland County. A gene commonly associated with enterococci from humans was detected in samples from Paint Creek at Rochester and Evans Ditch at Southfield, indicating that human fecal waste is a possible source of fecal contamination at these sites. E. coli resistant to the cephalosporin antibiotics (cefoxitin and/ or ceftriaxone) were found at all sites on at least one occasion. The highest percentages of E. coli isolates resistant to cefoxitin and ceftriaxone were 71 percent (Clinton River at Auburn Hills) and 19 percent (Sashabaw Creek near Drayton Plains), respectively. Cephalosporin-resistant E. coli was detected more frequently in samples from intensively urbanized or industrialized areas than in samples from less urbanized areas. VRE were not detected in any sample collected in this study. Multiple antibiotics (azithromycin, erythromycin, ofloxacin, sulfamethoxazole, and trimethoprim) were detected in water samples from the Clinton River at Auburn Hills, and tylosin (an antibiotic used in veterinary medicine and livestock production that belongs to the macrolide group, along with erythromycin) was detected in one water sample from Paint Creek at Rochester. Concentrations of total mercury were as high as 19.8 nanograms per liter (Evans Ditch at Southfield). There was no relation among percentage of antibiotic-resistant bacteria and measured concentrations of antibiotics or mercury in the water. Genetic elements capable of exchanging multiple antibiotic-resistance

  17. The Interaction between Heterotrophic Bacteria and Coliform, Fecal Coliform, Fecal Streptococci Bacteria in the Water Supply Networks.

    PubMed

    Amanidaz, Nazak; Zafarzadeh, Ali; Mahvi, Amir Hossein

    2015-12-01

    This study investigated the interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in water supply networks. This study was conducted during 2013 on water supply distribution network in Aq Qala City, Golestan Province, Northern Iran and standard methods were applied for microbiological analysis. The surface method was applied to test the heterotrophic bacteria and MPN method was used for coliform, fecal coliform and fecal streptococci bacteria measurements. In 114 samples, heterotrophic bacteria count were over 500 CFU/ml, which the amount of fecal coliform, coliform, and fecal streptococci were 8, 32, and 20 CFU/100 ml, respectively. However, in the other 242 samples, with heterotrophic bacteria count being less than 500 CFU/ml, the amount of fecal coliform, coliform, and fecal streptococci was 7, 23, and 11 CFU/100ml, respectively. The relationship between heterotrophic bacteria, coliforms and fecal streptococci was highly significant (P<0.05). We observed the concentration of coliforms, fecal streptococci bacteria being high, whenever the concentration of heterotrophic bacteria in the water network systems was high. Interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in the Aq Qala City water supply networks was not notable. It can be due to high concentrations of organic carbon, bio-films and nutrients, which are necessary for growth, and survival of all microorganisms.

  18. The Interaction between Heterotrophic Bacteria and Coliform, Fecal Coliform, Fecal Streptococci Bacteria in the Water Supply Networks

    PubMed Central

    AMANIDAZ, Nazak; ZAFARZADEH, Ali; MAHVI, Amir Hossein

    2015-01-01

    Background: This study investigated the interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in water supply networks. Methods: This study was conducted during 2013 on water supply distribution network in Aq Qala City, Golestan Province, Northern Iran and standard methods were applied for microbiological analysis. The surface method was applied to test the heterotrophic bacteria and MPN method was used for coliform, fecal coliform and fecal streptococci bacteria measurements. Results: In 114 samples, heterotrophic bacteria count were over 500 CFU/ml, which the amount of fecal coliform, coliform, and fecal streptococci were 8, 32, and 20 CFU/100 ml, respectively. However, in the other 242 samples, with heterotrophic bacteria count being less than 500 CFU/ml, the amount of fecal coliform, coliform, and fecal streptococci was 7, 23, and 11 CFU/100ml, respectively. The relationship between heterotrophic bacteria, coliforms and fecal streptococci was highly significant (P<0.05). We observed the concentration of coliforms, fecal streptococci bacteria being high, whenever the concentration of heterotrophic bacteria in the water network systems was high. Conclusion: Interaction between heterotrophic bacteria and coliform, fecal coliforms, fecal streptococci bacteria in the Aq Qala City water supply networks was not notable. It can be due to high concentrations of organic carbon, bio-films and nutrients, which are necessary for growth, and survival of all microorganisms. PMID:26811820

  19. Occurrence of antimicrobial resistance in bacteria from diagnostic samples from dogs.

    PubMed

    Pedersen, Karl; Pedersen, Kristina; Jensen, Helene; Finster, Kai; Jensen, Vibeke F; Heuer, Ole E

    2007-10-01

    To study the occurrence of antimicrobial resistance among common bacterial pathogens from dogs and relate resistance patterns to data on consumption of antimicrobials. The antimicrobial susceptibility patterns of 201 Staphylococcus intermedius, 37 Streptococcus canis, 39 Pseudomonas aeruginosa, 25 Pasteurella multocida, 29 Proteus spp. and 449 Escherichia coli isolates from clinical submissions from dogs were determined by a broth-dilution method for determination of minimal inhibitory concentration. Data for consumption of antimicrobials were retrieved from VetStat, a national database for reporting antimicrobial prescriptions. The majority of the antimicrobials prescribed for dogs were broad-spectrum compounds, and extended-spectrum penicillins, cephalosporins and sulphonamides + trimethoprim together accounted for 81% of the total amount used for companion animals. Resistance to cephalosporins and amoxicillin with clavulanic acid was very low for all bacterial species examined, except for P. aeruginosa, and resistance to sulphonamides and trimethoprim was low for most species. Among the S. intermedius isolates, 60.2% were resistant to penicillin, 30.2% to fusidic acid and 27.9% to macrolides. Among E. coli isolates, the highest level of resistance was recorded for ampicillin, sulphonamides, trimethoprim, tetracyclines and streptomycin. Certain differences in resistance patterns between isolates from different sites or organs were noticed for E. coli, S. intermedius and Proteus isolates. This investigation provided data on occurrence of antimicrobial resistance in important pathogenic bacteria from dogs, which may be useful for the small animal practitioner. Resistance was low to the compounds that were most often used, but unfortunately, these compounds were broad-spectrum. Data on resistance and usage may form a background for the establishment of a set of recommendations for prudent use of antimicrobials for companion animals.

  20. The effect of conventional wastewater treatment on the levels of antimicrobial-resistant bacteria in effluent: a meta-analysis of current studies.

    PubMed

    Harris, Suvi; Cormican, Martin; Cummins, Enda

    2012-12-01

    Antimicrobial agents in the environment are a cause for concern. Antimicrobial drug residues and their metabolites reach the aquatic and terrestrial environment primarily through wastewater treatment plants (WWTP). In addition to the potential direct negative health and environmental effects, there is potential for the development of antimicrobial-resistant bacteria. Residue levels below the minimum inhibitory concentration for a bacterial species can be important in selection of resistance. There is uncertainty associated with resistance formation during WWTP processing. A meta-analysis study was carried out to analyse the effect of WWTP processing on the levels of antimicrobial-resistant bacteria within bacterial populations. An analysis of publications relating to multiple antimicrobial-resistant (MAR) bacteria (n = 61), single antimicrobial-resistant (SAR) E. coli (n = 81) and quinolone/fluoroquinolone-resistant (FR) bacteria (n = 19) was carried out. The odds-ratio (OR) of MAR (OR = 1.60, p < 0.01), SAR (OR = 1.33, p < 0.01) and FR (OR = 1.19, p < 0.01) bacteria was determined. The results infer that WWTP processing results in an increase in the proportion of resistant bacteria in effluent, even though the overall bacterial population may have reduced (i.e. a reduction in total bacterial numbers but an increase in the percentage of resistant bacteria). The results support the need for further research into the development of antimicrobial-resistant strains and possible selective pressures operating in WWTPs.

  1. Antimicrobial Resistance in the Food Chain: A Review

    PubMed Central

    Verraes, Claire; Van Boxstael, Sigrid; Van Meervenne, Eva; Van Coillie, Els; Butaye, Patrick; Catry, Boudewijn; de Schaetzen, Marie-Athénaïs; Van Huffel, Xavier; Imberechts, Hein; Dierick, Katelijne; Daube, George; Saegerman, Claude; De Block, Jan; Dewulf, Jeroen; Herman, Lieve

    2013-01-01

    Antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. Antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance traits. Food can be contaminated with antimicrobial resistant bacteria and/or antimicrobial resistance genes in several ways. A first way is the presence of antibiotic resistant bacteria on food selected by the use of antibiotics during agricultural production. A second route is the possible presence of resistance genes in bacteria that are intentionally added during the processing of food (starter cultures, probiotics, bioconserving microorganisms and bacteriophages). A last way is through cross-contamination with antimicrobial resistant bacteria during food processing. Raw food products can be consumed without having undergone prior processing or preservation and therefore hold a substantial risk for transfer of antimicrobial resistance to humans, as the eventually present resistant bacteria are not killed. As a consequence, transfer of antimicrobial resistance genes between bacteria after ingestion by humans may occur. Under minimal processing or preservation treatment conditions, sublethally damaged or stressed cells can be maintained in the food, inducing antimicrobial resistance build-up and enhancing the risk of resistance transfer. Food processes that kill bacteria in food products, decrease the risk of transmission of antimicrobial resistance. PMID:23812024

  2. Incidence of antimicrobial-resistance genes and integrons in antibiotic-resistant bacteria isolated from eels and aquaculture ponds.

    PubMed

    Lin, Mao; Wu, Xiaomei; Yan, Qingpi; Ma, Ying; Huang, Lixing; Qin, Yingxue; Xu, Xiaojin

    2016-07-07

    The overuse of antimicrobials in aquaculture has promoted the selection of antimicrobial-resistant bacteria. Here we investigated the abundance of antimicrobial-resistance genes and integrons in 108 strains of antibiotic-resistant bacteria isolated from eels and aquaculture ponds in China. Conventional PCR was implemented to examine common antibiotic-resistance genes, integrons, and their gene cassette arrays. The results showed that the antibiotic-resistance genes blaTEM, tetC, sulI, aadA, floR, and qnrB were detected at high percentages, as were a number of other resistance genes. Class I integrons were present in 79.63% of the strains, and 10 out of 108 isolates carried class II integrons. Class III integrons were not detected. Three strains carried both class I and class II integrons, and 73.26% of the class I integron-positive isolates contained the qacEΔ1/sul1 gene. Fourteen types of integron cassette arrays were found among class I integron-positive isolates. A new array, dfrB4-catB3-blaOXA-10-aadA1, was discovered in this study. The gene cassette array dfrA12-orfF-aadA2 was the most widely distributed. In summary, 23 different gene cassettes encoding resistance to 8 classes of antibiotics were identified in the class I integrons, and the main cassettes contained genes encoding resistance to aminoglycosides (aad) and trimethoprim (dfr). All class II integron-positive strains had only a single gene cassette array, viz. dfrA1-catB2-sat2-aadA1. High levels of antimicrobial-resistance genes and integrons in eels and auqauculture ponds suggest that the overuse of antimicrobials should be strictly controlled and that the levels of bacterial antimicrobial-resistance genes in aquaculture should be monitored.

  3. Tetracycline improved the efficiency of other antimicrobials against Gram-negative multidrug-resistant bacteria.

    PubMed

    Mawabo, Isabelle K; Noumedem, Jaurès A K; Kuiate, Jules R; Kuete, Victor

    2015-01-01

    Treatment of infectious diseases with antimicrobials constituted a great achievement in the history of medicine. Unfortunately, the emergence of resistant strains of bacteria to all classes of antimicrobials limited their efficacy. The present study was aimed at evaluating the effect of combinations of antibiotics on multi-drug resistant Gram-negative (MDRGN) bacteria. A liquid micro-broth dilution method was used to evaluate the antibacterial activity of 10 different classes of antimicrobials on 20 bacterial strains belonging to six different species. The antimicrobials were associated with phenylalanine β-naphthylamide (PAβN), an efflux pump inhibitor, and with other antimicrobials at their sub-inhibitory concentrations. The effectiveness of each combination was monitored using the minimal inhibitory concentration (MIC) and the fractional inhibitory concentration (FIC). Most of the antimicrobials tested showed low antibacterial activity with a MIC value of 128 mg/L on a majority of the bacterial strains, justifying their multidrug-resistant (MDR) profile. Synergistic effects were mostly observed (FIC≤0.5) when ampicillin (AMP), cloxacillin (CLX), erythromycin (ERY), chloramphenicol (CHL), kanamycin (KAN) and streptomycin (STR) were combined with tetracycline (TET) at the sub-inhibitory concentration of MIC/5 or MIC/10. The results of the present work suggest that the association of several antimicrobials with TET could improve the fight against MDRGN bacterial species. Copyright © 2014 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

  4. Antimicrobial resistance in generic Escherichia coli isolates from wild small mammals living in swine farm, residential, landfill, and natural environments in southern Ontario, Canada.

    PubMed

    Allen, Samantha E; Boerlin, Patrick; Janecko, Nicol; Lumsden, John S; Barker, Ian K; Pearl, David L; Reid-Smith, Richard J; Jardine, Claire

    2011-02-01

    To assess the impacts of different types of human activity on the development of resistant bacteria in the feces of wild small mammals, we compared the prevalences and patterns of antimicrobial resistance and resistance genes in generic Escherichia coli and Salmonella enterica isolates from fecal samples collected from wild small mammals living in four environments: swine farms, residential areas, landfills, and natural habitats. Resistance to antimicrobials was observed in E. coli isolates from animals in all environments: 25/52 (48%) animals trapped at swine farms, 6/69 (9%) animals trapped in residential areas, 3/20 (15%) animals trapped at landfills, and 1/22 (5%) animals trapped in natural habitats. Animals trapped on farms were significantly more likely to carry E. coli isolates with resistance to tetracycline, ampicillin, sulfisoxazole, and streptomycin than animals trapped in residential areas. The resistance genes sul2, aadA, and tet(A) were significantly more likely to be detected in E. coli isolates from animals trapped on farms than from those trapped in residential areas. Three S. enterica serotypes (Give, Typhimurium, and Newport) were recovered from the feces of 4/302 (1%) wild small mammals. All Salmonella isolates were pansusceptible. Our results show that swine farm origin is significantly associated with the presence of resistant bacteria and resistance genes in wild small mammals in southern Ontario, Canada. However, resistant fecal bacteria were found in small mammals living in all environments studied, indicating that environmental exposure to antimicrobials, antimicrobial residues, resistant bacteria, or resistance genes is widespread.

  5. Use of natural antimicrobials to increase antibiotic susceptibility of drug resistant bacteria.

    PubMed

    Palaniappan, Kavitha; Holley, Richard A

    2010-06-15

    Plant-derived antibacterial compounds may be of value as a novel means for controlling antibiotic resistant zoonotic pathogens which contaminate food animals and their products. Individual activity of natural antimicrobials (eugenol, thymol, carvacrol, cinnamaldehyde, allyl isothiocyanate (AIT)) and activity when paired with an antibiotic was studied using broth microdilution and checkerboard methods. In the latter assays, fractional inhibitory concentration (FIC) values were calculated to characterize interactions between the inhibitors. Bacteria tested were chosen because of their resistance to at least one antibiotic which had a known genetic basis. Substantial susceptibility of these bacteria toward the natural antimicrobials and a considerable reduction in the minimum inhibitory concentrations (MIC's) of the antibiotics were noted when paired combinations of antimicrobial and antibiotic were used. In the interaction study, thymol and carvacrol were found to be highly effective in reducing the resistance of Salmonella Typhimurium SGI 1 (tet A) to ampicillin, tetracycline, penicillin, bacitracin, erythromycin and novobiocin (FIC<0.4) and resistance of Streptococcus pyogenes ermB to erythromycin (FIC<0.5). With Escherichia coli N00 666, thymol and cinnamaldehyde were found to have a similar effect (FIC<0.4) in reducing the MIC's of ampicillin, tetracycline, penicillin, erythromycin and novobiocin. Carvacrol, thymol (FIC<0.3) and cinnamaldehyde (FIC<0.4) were effective against Staphylococcus aureus blaZ and in reducing the MIC's of ampicillin, penicillin and bacitracin. Allyl isothiocyanate (AIT) was effective in reducing the MIC of erythromycin (FIC<0.3) when tested against S. pyogenes. Fewer combinations were found to be synergistic when the decrease in viable population (log DP) was calculated. Together, fractional inhibitory concentrations < or = 0.5 and log DP<-1 indicated synergistic action between four natural antimicrobials and as many as three antibiotics

  6. Effects of chlortetracycline and copper supplementation on antimicrobial resistance of fecal Escherichia coli from weaned pigs.

    PubMed

    Agga, G E; Scott, H M; Amachawadi, R G; Nagaraja, T G; Vinasco, J; Bai, J; Norby, B; Renter, D G; Dritz, S S; Nelssen, J L; Tokach, M D

    2014-06-01

    Feed-grade chlortetracycline (CTC) and copper are both widely utilized in U.S. pig production. Cluster randomized experiment was conducted to evaluate the effects of CTC and copper supplementation in weaned pigs on antimicrobial resistance (AMR) among fecal Escherichia coli. Four treatment groups: control, copper, CTC, or copper plus CTC were randomly allocated to 32 pens with five pigs per pen. Fecal samples were collected weekly from three pigs per pen for six weeks. Two E. coli isolates per fecal sample were tested for phenotypic and genotypic resistance against antibiotics and copper. Data were analyzed with multilevel mixed effects logistic regression, multivariate probit analysis and discrete time survival analysis. CTC-supplementation was significantly (99% [95% CI=98-100%]) associated with increased tetracycline resistance compared to the control group (95% [95% CI=94-97%]). Copper supplementation was associated with decreased resistance to most of the antibiotics tested, including cephalosporins, over the treatment period. Overall, 91% of the E. coli isolates were multidrug resistant (MDR) (resistant to ≥3 antimicrobial classes). tetA and blaCMY-2 genes were positively associated (P<0.05) with MDR categorization, while tetB and pcoD were negatively associated with MDR. tetA and blaCMY-2 were positively associated with each other and in turn, these were negatively associated with both tetB and pcoD genes; which were also positively associated with one another. Copper minimum inhibitory concentration was not affected by copper supplementation or by pcoD gene carriage. CTC supplementation was significantly associated with increased susceptibilities of E. coli to copper (HR=7 [95% CI=2.5-19.5]) during treatment period. In conclusion, E. coli isolates from the nursery pigs exhibited high levels of antibiotic resistance, with diverse multi-resistant phenotypic profiles. The roles of copper supplementation in pig production, and pco-mediated copper resistance

  7. Control of the development and prevalence of antimicrobial resistance in bacteria of food animal origin in Japan: a new approach for risk management of antimicrobial veterinary medicinal products in Japan.

    PubMed

    Asai, Tetsuo; Hiki, Mototaka; Ozawa, Manao; Koike, Ryoji; Eguchi, Kaoru; Kawanishi, Michiko; Kojima, Akemi; Endoh, Yuuko S; Hamamoto, Shuichi; Sakai, Masato; Sekiya, Tatsuro

    2014-03-01

    Antimicrobial agents are essential for controlling bacterial disease in food-producing animals and contribute to the stable production of safe animal products. The use of antimicrobial agents in these animals affects the emergence and prevalence of antimicrobial resistance in bacteria isolated from animals and animal products. As disease-causing bacteria are often transferred from food-producing animals to humans, the food chain is considered a route of transmission for the resistant bacteria and/or resistance genes. The Food Safety Commission of Japan (FSC) has been assessing the risk posed to human health by the transmission of antimicrobial-resistant bacteria from livestock products via the food chain. In addition to the FSC's risk assessments, the Japanese Ministry of Agriculture, Forestry and Fisheries has developed risk-management guidelines to determine feasible risk-management options for the use of antimicrobial veterinary medicinal products during farming practices. This report includes information on risk assessment and novel approaches for risk management of antimicrobial veterinary medicinal products for mitigating the risk of development and prevalence of antimicrobial resistance in bacteria originating from food-producing animals in Japan.

  8. Preliminary survey of antibiotic-resistant fecal indicator bacteria and pathogenic Escherichia coli from river-water samples collected in Oakland County, Michigan, 2003

    USGS Publications Warehouse

    Fogarty, Lisa R.; Duris, Joseph W.; Aichele, Stephen S.

    2005-01-01

    A preliminary study was done in Oakland County, Michigan, to determine the concentration of fecal indicator bacteria (fecal coliform bacteria and enterococci), antibiotic resistance patterns of these two groups, and the presence of potentially pathogenic Escherichia coli (E. coli). For selected sites, specific members of these groups [E. coli, Enterococcus faecium (E. faecium) and Enterococcus faecalis (E. faecalis)] were isolated and tested for levels of resistance to specific antibiotics used to treat human infections by pathogens in these groups and for their potential to transfer these resistances. In addition, water samples from all sites were tested for indicators of potentially pathogenic E. coli by three assays: a growth-based assay for sorbitol-negative E. coli, an immunological assay for E. coli O157, and a molecular assay for three virulence and two serotype genes. Samples were also collected from two non-urbanized sites outside of Oakland County. Results from the urbanized Oakland County area were compared to those from these two non-urbanized sites. Fecal indicator bacteria concentrations exceeded State of Michigan recreational water-quality standards and (or) recommended U.S. Environmental Protection Agency (USEPA) standards in samples from all but two Oakland County sites. Multiple-antibiotic-resistant fecal coliform bacteria were found at all sites, including two reference sites from outside the county. Two sites (Stony Creek and Paint Creek) yielded fecal coliform isolates resistant to all tested antibiotics. Patterns indicative of extended-spectrum-β-lactamase (ESBL)- producing fecal coliform bacteria were found at eight sites in Oakland County and E. coli resistant to clinically significant antibiotics were recovered from the River Rouge, Clinton River, and Paint Creek. Vancomycin-resistant presumptive enterococci were found at six sites in Oakland County and were not found at the reference sites. Evidence of acquired antibiotic resistances was

  9. Novel antimicrobial peptide CPF-C1 analogs with superior stabilities and activities against multidrug-resistant bacteria.

    PubMed

    Xie, Junqiu; Zhao, Qian; Li, Sisi; Yan, Zhibin; Li, Jing; Li, Yao; Mou, Lingyun; Zhang, Bangzhi; Yang, Wenle; Miao, Xiaokang; Jiang, Xianxing; Wang, Rui

    2017-11-01

    As numerous clinical isolates are resistant to most conventional antibiotics, infections caused by multidrug-resistant bacteria are associated with a higher death rate. Antimicrobial peptides show great potential as new antibiotics. However, a major obstacle to the development of these peptides as useful drugs is their low stability. To overcome the problem of the natural antimicrobial peptide CPF-C1, we designed and synthesized a series of analogs. Our results indicated that by introducing lysine, which could increase the number of positive charges, and by introducing tryptophan, which could increase the hydrophobicity, we could improve the antimicrobial activity of the peptides against multidrug-resistant strains. The introduction of d-amino acids significantly improved stability. Certain analogs demonstrated antibiofilm activities. In mechanistic studies, the analogs eradicated bacteria not just by interrupting the bacterial membranes, but also by linking to DNA, which was not impacted by known mechanisms of resistance. In a mouse model, certain analogs were able to significantly reduce the bacterial load. Among the analogs, CPF-9 was notable due to its greater antimicrobial potency in vitro and in vivo and its superior stability, lower hemolytic activity, and higher antibiofilm activity. This analog is a potential antibiotic candidate for treating infections induced by multidrug-resistant bacteria. © 2017 John Wiley & Sons A/S.

  10. Mechanisms of antimicrobial resistant Salmonella enterica transmission associated with starling-livestock interactions.

    PubMed

    Carlson, James C; Hyatt, Doreene R; Ellis, Jeremy W; Pipkin, David R; Mangan, Anna M; Russell, Michael; Bolte, Denise S; Engeman, Richard M; DeLiberto, Thomas J; Linz, George M

    2015-08-31

    Bird-livestock interactions have been implicated as potential sources for bacteria within concentrated animal feeding operations (CAFO). European starlings (Sturnus vulgaris) in particular are known to contaminate cattle feed and water with Salmonella enterica through their fecal waste. We propose that fecal waste is not the only mechanisms through which starlings introduce S. enterica to CAFO. The goal of this study was to assess if starlings can mechanically move S. enterica. We define mechanical movement as the transportation of media containing S. enterica, on the exterior of starlings within CAFO. We collected 100 starlings and obtained external wash and gastrointestinal tract (GI) samples. We also collected 100 samples from animal pens. Within each pen we collected one cattle fecal, feed, and water trough sample. Isolates from all S. enterica positive samples were subjected to antimicrobial susceptibility testing. All sample types, including 17% of external starling wash samples, contained S. enterica. All sample types had at least one antimicrobial resistant (AMR) isolate and starling GI samples harbored multidrug resistant S. enterica. The serotypes isolated from the starling external wash samples were all found in the farm environment and 11.8% (2/17) of isolates from positive starling external wash samples were resistant to at least one class of antibiotics. This study provides evidence of a potential mechanism of wildlife introduced microbial contamination in CAFO. Mechanical movement of microbiological hazards, by starlings, should be considered a potential source of bacteria that is of concern to veterinary, environmental and public health. Published by Elsevier B.V.

  11. Antimicrobial-resistant Gram-negative bacteria in febrile neutropenic patients with cancer: current epidemiology and clinical impact.

    PubMed

    Trecarichi, Enrico M; Tumbarello, Mario

    2014-04-01

    In the recent years, several studies involving cancer patients have demonstrated a clear trend in the epidemiology of bacterial infections showing a shift in the prevalence from Gram-positive to Gram-negative bacteria and the extensive emergence of antimicrobial-resistant strains among Gram-negatives isolated from the blood. The aim of this systematic review was to examine the recent trends in epidemiology and antimicrobial resistance in Gram-negatives recovered from neutropenic cancer patients, with particular emphasis on the impact of antimicrobial resistance on the clinical outcome of severe infections caused by such microorganisms. Overall, from 2007 to date, the rate of Gram-negative bacteria recovery ranged from 24.7 to 75.8% (mean 51.3%) in cancer patient cohorts. Escherichia coli represented the most common species (mean frequency of isolation 32.1%) among the Gram-negatives, followed by Pseudomonas aeruginosa (mean frequency of isolation 20.1%). An increasing frequency of Acinetobacter spp. and Stenotrophomonas maltophilia was also reported. Increased rates of multidrug-resistant Gram-negative strains have been highlighted among Enterobacteriaceae and nonfermenting Gram-negative rods, despite discontinuation of fluoroquinolone-based antibacterial prophylaxis for neutropenic patients. In addition, antimicrobial resistance and/or the inadequacy of empirical antibiotic treatment have been frequently linked to a worse outcome in cancer patients with bloodstream infections caused by Gram-negative isolates. Sound knowledge of the local distribution of pathogens and their susceptibility patterns and prompt initiation of effective antimicrobial treatment for severe infections caused by Gram-negative bacteria are essential in cancer patients.

  12. Prevalence of antimicrobial drug resistant bacteria carried by in- and outpatients attending a secondary care hospital in Zambia.

    PubMed

    Nagelkerke, Marjolijn M B; Sikwewa, Kapembwa; Makowa, Dennis; de Vries, Irene; Chisi, Simon; Dorigo-Zetsma, J Wendelien

    2017-08-10

    Antimicrobial resistance is an increasing global health problem. Very little data on resistance patterns of pathogenic bacteria in low-income countries exist. The aim of this study was to measure the prevalence of antimicrobial drug resistant bacteria carried by in- and outpatients in the resource constraint setting of a secondary care hospital in Zambia. Nasal and rectal samples from 50 in- and 50 outpatients were collected. Patients were randomly selected and informed consent was obtained. Nasal samples were tested for the presence of methicillin-resistant Staphylococcus aureus (MRSA), and rectal samples for Gram-negative rods (family of Enterobacteriaceae) non-susceptible to gentamicin, ciprofloxacin and ceftriaxone. Additionally, E-tests were performed on ceftriaxone-resistant Enterobacteriaceae to detect extended-spectrum β-lactamases (ESBLs). 14% of inpatients carried S. aureus, and 18% of outpatients. No MRSA was found. 90% of inpatients and 48% of outpatients carried one or more Enterobacteriaceae strains (75% Escherichia coli and Klebsiella pneumonia) resistant to gentamicin, ciprofloxacin and/or ceftriaxone (p < 0.001). Among inpatients gentamicin resistance was most prevalent (in 78%), whereas among outpatients ciprofloxacin resistance prevailed (in 38%). All ceftriaxone-resistant Enterobacteriaceae were ESBL-positive; these were present in 52% of inpatients versus 12% of outpatients (p < 0.001). We conclude it is feasible to perform basic microbiological procedures in the hospital laboratory in a low-income country and generate data on antimicrobial susceptibility. The high prevalence of antimicrobial drug resistant Enterobacteriaceae carried by in- and outpatients is worrisome. In order to slow down antimicrobial resistance, surveillance data on local susceptibility patterns of bacteria are a prerequisite to generate guidelines for antimicrobial therapy, to guide in individual patient treatment and to support implementation of infection control

  13. Activity of Topical Antimicrobial Agents Against Multidrug-Resistant Bacteria Recovered from Burn Patients

    DTIC Science & Technology

    2010-01-01

    produced by Pseudomonas fluorescens [19] Inhibition of RNA and protein synthesis by targeting the isoleucine-binding site on the isoleucyl-transfer-RNA...multidrug-resistant (MDR) bacteria. We compared two methods of determining topical antimicrobial susceptibilities. Methods: Isolates of Pseudomonas ...aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), extended spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae, and

  14. Overcoming Antimicrobial Resistance in Bacteria Using Bioactive Magnetic Nanoparticles and Pulsed Electromagnetic Fields

    PubMed Central

    Novickij, Vitalij; Stanevičienė, Ramunė; Vepštaitė-Monstavičė, Iglė; Gruškienė, Rūta; Krivorotova, Tatjana; Sereikaitė, Jolanta; Novickij, Jurij; Servienė, Elena

    2018-01-01

    Nisin is a known bacteriocin, which exhibits a wide spectrum of antimicrobial activity, while commonly being inefficient against Gram-negative bacteria. In this work, we present a proof of concept of novel antimicrobial methodology using targeted magnetic nisin-loaded nano-carriers [iron oxide nanoparticles (NPs) (11–13 nm) capped with citric, ascorbic, and gallic acids], which are activated by high pulsed electric and electromagnetic fields allowing to overcome the nisin-resistance of bacteria. As a cell model the Gram-positive bacteria Bacillus subtilis and Gram-negative Escherichia coli were used. We have applied 10 and 30 kV cm-1 electric field pulses (100 μs × 8) separately and in combination with two pulsed magnetic field protocols: (1) high dB/dt 3.3 T × 50 and (2) 10 mT, 100 kHz, 2 min protocol to induce additional permeabilization and local magnetic hyperthermia. We have shown that the high dB/dt pulsed magnetic fields increase the antimicrobial efficiency of nisin NPs similar to electroporation or magnetic hyperthermia methods and a synergistic treatment is also possible. The results of our work are promising for the development of new methods for treatment of the drug-resistant foodborne pathogens to minimize the risks of invasive infections. PMID:29375537

  15. Overcoming Antimicrobial Resistance in Bacteria Using Bioactive Magnetic Nanoparticles and Pulsed Electromagnetic Fields.

    PubMed

    Novickij, Vitalij; Stanevičienė, Ramunė; Vepštaitė-Monstavičė, Iglė; Gruškienė, Rūta; Krivorotova, Tatjana; Sereikaitė, Jolanta; Novickij, Jurij; Servienė, Elena

    2017-01-01

    Nisin is a known bacteriocin, which exhibits a wide spectrum of antimicrobial activity, while commonly being inefficient against Gram-negative bacteria. In this work, we present a proof of concept of novel antimicrobial methodology using targeted magnetic nisin-loaded nano-carriers [iron oxide nanoparticles (NPs) (11-13 nm) capped with citric, ascorbic, and gallic acids], which are activated by high pulsed electric and electromagnetic fields allowing to overcome the nisin-resistance of bacteria. As a cell model the Gram-positive bacteria Bacillus subtilis and Gram-negative Escherichia coli were used. We have applied 10 and 30 kV cm -1 electric field pulses (100 μs × 8) separately and in combination with two pulsed magnetic field protocols: (1) high d B /d t 3.3 T × 50 and (2) 10 mT, 100 kHz, 2 min protocol to induce additional permeabilization and local magnetic hyperthermia. We have shown that the high d B /d t pulsed magnetic fields increase the antimicrobial efficiency of nisin NPs similar to electroporation or magnetic hyperthermia methods and a synergistic treatment is also possible. The results of our work are promising for the development of new methods for treatment of the drug-resistant foodborne pathogens to minimize the risks of invasive infections.

  16. Antimicrobial susceptibility of starter culture bacteria used in Norwegian dairy products.

    PubMed

    Katla, A K; Kruse, H; Johnsen, G; Herikstad, H

    2001-07-20

    Commercial starter culture bacteria are widely used in the production of dairy products and could represent a potential source for spread of genes encoding resistance to antimicrobial agents. To learn more about the antimicrobial susceptibility of starter culture bacteria used in Norwegian dairy products, a total of 189 isolates of lactic acid bacteria were examined for susceptibility to ampicillin, penicillin G, cephalothin, vancomycin, bacitracin, gentamicin, streptomycin, erythromycin, tetracycline, chloramphenicol, quinupristin/dalfopristin, ciprofloxacin, trimethoprim and sulphadiazine using Etest for MIC determination. Most of the isolates (140) originated from 39 dairy products (yoghurt, sour cream, fermented milk and cheese), while 49 were isolated directly from nine commercial cultures. The bacteria belonged to the genera Lactobacillus, Lactococcus, Leuconostoc and Streptococcus. Only one of the 189 isolates was classified as resistant to an antimicrobial agent included in the study. This isolate, a lactobacillus, was classified as high level resistant to streptomycin. The remaining isolates were not classified as resistant to the antimicrobial agents included other than to those they are known to have a natural reduced susceptibility to. Thus, starter culture bacteria in Norwegian dairy products do not seem to represent a source for spread of genes encoding resistance to antimicrobial agents.

  17. [Analysis on the antimicrobial resistance of lactic acid bacteria isolated from the yogurt sold in China].

    PubMed

    Fan, Qin; Liu, Shuliang; Li, Juan; Huang, Tingting

    2012-05-01

    To analyze the antimicrobial susceptibility of lactic acid bacteria (LAB) from yogurt, and to provide references for evaluating the safety of LAB and screening safe strains. The sensitivity of 43 LAB strains, including 14 strains of Streptococcus thermophilus, 12 strains of Lactobacillus acidophilus, 9 strains of Lactobacillus bulgaricus and 8 strains of Bifidobacterium, to 22 antibiotics were tested by agar plate dilution method. All 43 LAB strains were resistant to trimethoprim, nalidixic acid, ciprofloxacin, lomefloxacin, danofloxacin and polymyxin E. Their resistances to kanamycin, tetracycline, clindamycin, doxycycline and cephalothin were varied. The sensitivity to other antibiotics were sensitive or moderate. All isolates were multidrug-resistant. The antimicrobial resistance of tested LAB strains was comparatively serious, and continuously monitoring their antimicrobial resistance and evaluating their safety should be strengthened.

  18. Antimicrobial peptides as potential anti-biofilm agents against multidrug-resistant bacteria.

    PubMed

    Chung, Pooi Yin; Khanum, Ramona

    2017-08-01

    Bacterial resistance to commonly used drugs has become a global health problem, causing increased infection cases and mortality rate. One of the main virulence determinants in many bacterial infections is biofilm formation, which significantly increases bacterial resistance to antibiotics and innate host defence. In the search to address the chronic infections caused by biofilms, antimicrobial peptides (AMP) have been considered as potential alternative agents to conventional antibiotics. Although AMPs are commonly considered as the primitive mechanism of immunity and has been extensively studied in insects and non-vertebrate organisms, there is now increasing evidence that AMPs also play a crucial role in human immunity. AMPs have exhibited broad-spectrum activity against many strains of Gram-positive and Gram-negative bacteria, including drug-resistant strains, and fungi. In addition, AMPs also showed synergy with classical antibiotics, neutralize toxins and are active in animal models. In this review, the important mechanisms of action and potential of AMPs in the eradication of biofilm formation in multidrug-resistant pathogen, with the goal of designing novel antimicrobial therapeutics, are discussed. Copyright © 2017. Published by Elsevier B.V.

  19. Salmon Aquaculture and Antimicrobial Resistance in the Marine Environment

    PubMed Central

    Buschmann, Alejandro H.; Tomova, Alexandra; López, Alejandra; Maldonado, Miguel A.; Henríquez, Luis A.; Ivanova, Larisa; Moy, Fred; Godfrey, Henry P.; Cabello, Felipe C.

    2012-01-01

    Antimicrobials used in salmon aquaculture pass into the marine environment. This could have negative impacts on marine environmental biodiversity, and on terrestrial animal and human health as a result of selection for bacteria containing antimicrobial resistance genes. We therefore measured the numbers of culturable bacteria and antimicrobial-resistant bacteria in marine sediments in the Calbuco Archipelago, Chile, over 12-month period at a salmon aquaculture site approximately 20 m from a salmon farm and at a control site 8 km distant without observable aquaculture activities. Three antimicrobials extensively used in Chilean salmon aquaculture (oxytetracycline, oxolinic acid, and florfenicol) were studied. Although none of these antimicrobials was detected in sediments from either site, traces of flumequine, a fluoroquinolone antimicrobial also widely used in Chile, were present in sediments from both sites during this period. There were significant increases in bacterial numbers and antimicrobial-resistant fractions to oxytetracycline, oxolinic acid, and florfenicol in sediments from the aquaculture site compared to those from the control site. Interestingly, there were similar numbers of presumably plasmid-mediated resistance genes for oxytetracycline, oxolinic acid and florfenicol in unselected marine bacteria isolated from both aquaculture and control sites. These preliminary findings in one location may suggest that the current use of large amounts of antimicrobials in Chilean aquaculture has the potential to select for antimicrobial-resistant bacteria in marine sediments. PMID:22905164

  20. Public health risk of antimicrobial resistance transfer from companion animals.

    PubMed

    Pomba, Constança; Rantala, Merja; Greko, Christina; Baptiste, Keith Edward; Catry, Boudewijn; van Duijkeren, Engeline; Mateus, Ana; Moreno, Miguel A; Pyörälä, Satu; Ružauskas, Modestas; Sanders, Pascal; Teale, Christopher; Threlfall, E John; Kunsagi, Zoltan; Torren-Edo, Jordi; Jukes, Helen; Törneke, Karolina

    2017-04-01

    Antimicrobials are important tools for the therapy of infectious bacterial diseases in companion animals. Loss of efficacy of antimicrobial substances can seriously compromise animal health and welfare. A need for the development of new antimicrobials for the therapy of multiresistant infections, particularly those caused by Gram-negative bacteria, has been acknowledged in human medicine and a future corresponding need in veterinary medicine is expected. A unique aspect related to antimicrobial resistance and risk of resistance transfer in companion animals is their close contact with humans. This creates opportunities for interspecies transmission of resistant bacteria. Yet, the current knowledge of this field is limited and no risk assessment is performed when approving new veterinary antimicrobials. The objective of this review is to summarize the current knowledge on the use and indications for antimicrobials in companion animals, drug-resistant bacteria of concern among companion animals, risk factors for colonization of companion animals with resistant bacteria and transmission of antimicrobial resistance (bacteria and/or resistance determinants) between animals and humans. The major antimicrobial resistance microbiological hazards originating from companion animals that directly or indirectly may cause adverse health effects in humans are MRSA, methicillin-resistant Staphylococcus pseudintermedius, VRE, ESBL- or carbapenemase-producing Enterobacteriaceae and Gram-negative bacteria. In the face of the previously recognized microbiological hazards, a risk assessment tool could be applied in applications for marketing authorization for medicinal products for companion animals. This would allow the approval of new veterinary medicinal antimicrobials for which risk levels are estimated as acceptable for public health. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For

  1. Longitudinal characterization of antimicrobial resistance genes in feces shed from cattle fed different subtherapeutic antibiotics

    PubMed Central

    2011-01-01

    Background Environmental transmission of antimicrobial-resistant bacteria and resistance gene determinants originating from livestock is affected by their persistence in agricultural-related matrices. This study investigated the effects of administering subtherapeutic concentrations of antimicrobials to beef cattle on the abundance and persistence of resistance genes within the microbial community of fecal deposits. Cattle (three pens per treatment, 10 steers per pen) were administered chlortetracycline, chlortetracycline plus sulfamethazine, tylosin, or no antimicrobials (control). Model fecal deposits (n = 3) were prepared by mixing fresh feces from each pen into a single composite sample. Real-time PCR was used to measure concentrations of tet, sul and erm resistance genes in DNA extracted from composites over 175 days of environmental exposure in the field. The microbial communities were analyzed by quantification and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S-rRNA. Results The concentrations of 16S-rRNA in feces were similar across treatments and increased by day 56, declining thereafter. DGGE profiles of 16S-rRNA differed amongst treatments and with time, illustrating temporal shifts in microbial communities. All measured resistance gene determinants were quantifiable in feces after 175 days. Antimicrobial treatment differentially affected the abundance of certain resistance genes but generally not their persistence. In the first 56 days, concentrations of tet(B), tet(C), sul1, sul2, erm(A) tended to increase, and decline thereafter, whereas tet(M) and tet(W) gradually declined over 175 days. At day 7, the concentration of erm(X) was greatest in feces from cattle fed tylosin, compared to all other treatments. Conclusion The abundance of genes coding for antimicrobial resistance in bovine feces can be affected by inclusion of antibiotics in the feed. Resistance genes can persist in feces from cattle beyond 175 days with concentrations

  2. Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste

    PubMed Central

    Durso, Lisa M.; Harhay, Dayna M.; Schmidt, John W.

    2015-01-01

    This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two “low impact” environments (an urban lake and a relict prairie). Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR) Gram-negative (Escherichia coli and Salmonella enterica) and Gram-positive (enterococci) bacteria were determined from individual samples (n = 174). The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44) by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine), low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P < 0.05) in municipal samples than in cattle runoff or swine lagoon samples. In conclusion, we report that AMR is a very widespread phenomenon and that similar

  3. Antimicrobial-Resistant Bacterial Populations and Antimicrobial Resistance Genes Obtained from Environments Impacted by Livestock and Municipal Waste.

    PubMed

    Agga, Getahun E; Arthur, Terrance M; Durso, Lisa M; Harhay, Dayna M; Schmidt, John W

    2015-01-01

    This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal wastewater treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two "low impact" environments (an urban lake and a relict prairie). Multiple liquid and solid samples were collected from each environment. The prevalences and concentrations of antimicrobial-resistant (AMR) Gram-negative (Escherichia coli and Salmonella enterica) and Gram-positive (enterococci) bacteria were determined from individual samples (n = 174). The prevalences of 84 antimicrobial resistance genes in metagenomic DNA isolated from samples pooled (n = 44) by collection date, location, and sample type were determined. The prevalences and concentrations of AMR E. coli and Salmonella were similar among the livestock and municipal sample sources. The levels of erythromycin-resistant enterococci were significantly higher in liquid samples from cattle catchment ponds and swine waste lagoons than in liquid samples from municipal wastewater treatment facilities, but solid samples from these environments did not differ significantly. Similarly, trimethoprim/sulfamethoxazole-resistant E. coli concentrations were significantly higher in swine liquid than in municipal liquid samples, but there was no difference in solid samples. Multivariate analysis of the distribution of antimicrobial resistance genes using principal coordinate analysis showed distinct clustering of samples with livestock (cattle and swine), low impact environment and municipal samples forming three separate clusters. The numbers of class A beta-lactamase, class C beta-lactamase, and fluoroquinolone resistance genes detected were significantly higher (P < 0.05) in municipal samples than in cattle runoff or swine lagoon samples. In conclusion, we report that AMR is a very widespread phenomenon and that similar prevalences

  4. Establishing Statistical Equivalence of Data from Different Sampling Approaches for Assessment of Bacterial Phenotypic Antimicrobial Resistance

    PubMed Central

    2018-01-01

    ABSTRACT To assess phenotypic bacterial antimicrobial resistance (AMR) in different strata (e.g., host populations, environmental areas, manure, or sewage effluents) for epidemiological purposes, isolates of target bacteria can be obtained from a stratum using various sample types. Also, different sample processing methods can be applied. The MIC of each target antimicrobial drug for each isolate is measured. Statistical equivalence testing of the MIC data for the isolates allows evaluation of whether different sample types or sample processing methods yield equivalent estimates of the bacterial antimicrobial susceptibility in the stratum. We demonstrate this approach on the antimicrobial susceptibility estimates for (i) nontyphoidal Salmonella spp. from ground or trimmed meat versus cecal content samples of cattle in processing plants in 2013-2014 and (ii) nontyphoidal Salmonella spp. from urine, fecal, and blood human samples in 2015 (U.S. National Antimicrobial Resistance Monitoring System data). We found that the sample types for cattle yielded nonequivalent susceptibility estimates for several antimicrobial drug classes and thus may gauge distinct subpopulations of salmonellae. The quinolone and fluoroquinolone susceptibility estimates for nontyphoidal salmonellae from human blood are nonequivalent to those from urine or feces, conjecturally due to the fluoroquinolone (ciprofloxacin) use to treat infections caused by nontyphoidal salmonellae. We also demonstrate statistical equivalence testing for comparing sample processing methods for fecal samples (culturing one versus multiple aliquots per sample) to assess AMR in fecal Escherichia coli. These methods yield equivalent results, except for tetracyclines. Importantly, statistical equivalence testing provides the MIC difference at which the data from two sample types or sample processing methods differ statistically. Data users (e.g., microbiologists and epidemiologists) may then interpret practical relevance

  5. Establishing Statistical Equivalence of Data from Different Sampling Approaches for Assessment of Bacterial Phenotypic Antimicrobial Resistance.

    PubMed

    Shakeri, Heman; Volkova, Victoriya; Wen, Xuesong; Deters, Andrea; Cull, Charley; Drouillard, James; Müller, Christian; Moradijamei, Behnaz; Jaberi-Douraki, Majid

    2018-05-01

    To assess phenotypic bacterial antimicrobial resistance (AMR) in different strata (e.g., host populations, environmental areas, manure, or sewage effluents) for epidemiological purposes, isolates of target bacteria can be obtained from a stratum using various sample types. Also, different sample processing methods can be applied. The MIC of each target antimicrobial drug for each isolate is measured. Statistical equivalence testing of the MIC data for the isolates allows evaluation of whether different sample types or sample processing methods yield equivalent estimates of the bacterial antimicrobial susceptibility in the stratum. We demonstrate this approach on the antimicrobial susceptibility estimates for (i) nontyphoidal Salmonella spp. from ground or trimmed meat versus cecal content samples of cattle in processing plants in 2013-2014 and (ii) nontyphoidal Salmonella spp. from urine, fecal, and blood human samples in 2015 (U.S. National Antimicrobial Resistance Monitoring System data). We found that the sample types for cattle yielded nonequivalent susceptibility estimates for several antimicrobial drug classes and thus may gauge distinct subpopulations of salmonellae. The quinolone and fluoroquinolone susceptibility estimates for nontyphoidal salmonellae from human blood are nonequivalent to those from urine or feces, conjecturally due to the fluoroquinolone (ciprofloxacin) use to treat infections caused by nontyphoidal salmonellae. We also demonstrate statistical equivalence testing for comparing sample processing methods for fecal samples (culturing one versus multiple aliquots per sample) to assess AMR in fecal Escherichia coli These methods yield equivalent results, except for tetracyclines. Importantly, statistical equivalence testing provides the MIC difference at which the data from two sample types or sample processing methods differ statistically. Data users (e.g., microbiologists and epidemiologists) may then interpret practical relevance of the

  6. Antimicrobial-resistant bacterial populations and antimicrobial resistance genes obtained from environments impacted by livestock and municipal waste

    USDA-ARS?s Scientific Manuscript database

    This study compared the populations of antimicrobial-resistant bacteria and the repertoire of antimicrobial resistance genes in four environments: effluent of three municipal waste water treatment facilities, three cattle feedlot runoff catchment ponds, three swine waste lagoons, and two "low impact...

  7. Zinc and copper in animal feed – development of resistance and co-resistance to antimicrobial agents in bacteria of animal origin

    PubMed Central

    Yazdankhah, Siamak; Rudi, Knut; Bernhoft, Aksel

    2014-01-01

    Farmed animals such as pig and poultry receive additional Zn and Cu in their diets due to supplementing elements in compound feed as well as medical remedies. Enteral bacteria in farmed animals are shown to develop resistance to trace elements such as Zn and Cu. Resistance to Zn is often linked with resistance to methicillin in staphylococci, and Zn supplementation to animal feed may increase the proportion of multiresistant E. coli in the gut. Resistance to Cu in bacteria, in particular enterococci, is often associated with resistance to antimicrobial drugs like macrolides and glycopeptides (e.g. vancomycin). Such resistant bacteria may be transferred from the food-producing animals to humans (farmers, veterinarians, and consumers). Data on dose-response relation for Zn/Cu exposure and resistance are lacking; however, it seems more likely that a resistance-driven effect occurs at high trace element exposure than at more basal exposure levels. There is also lack of data which could demonstrate whether Zn/Cu-resistant bacteria may acquire antibiotic resistance genes/become antibiotics resistant, or if antibiotics-resistant bacteria are more capable to become Zn/Cu resistant than antibiotics-susceptible bacteria. Further research is needed to elucidate the link between Zn/Cu and antibiotic resistance in bacteria. PMID:25317117

  8. Diversity of plasmids and antimicrobial resistance genes in multidrug-resistant Escherichia coli isolated from healthy companion animals

    USDA-ARS?s Scientific Manuscript database

    The presence and transfer of antimicrobial resistance genes from commensal bacteria in companion animals to more pathogenic bacteria may contribute to dissemination of antimicrobial resistance. The purpose of this study was to determine antimicrobial resistance gene content and the presence of gene...

  9. Antimicrobial Use and Resistance in Swine Waste Treatment Systems▿

    PubMed Central

    Jindal, Archana; Kocherginskaya, Svetlana; Mehboob, Asma; Robert, Matthew; Mackie, Roderick I.; Raskin, Lutgarde; Zilles, Julie L.

    2006-01-01

    Chlortetracycline and the macrolide tylosin were identified as commonly used antimicrobials for growth promotion and prophylaxis in swine production. Resistance to these antimicrobials was measured throughout the waste treatment processes at five swine farms by culture-based and molecular methods. Conventional farm samples had the highest levels of resistance with both culture-based and molecular methods and had similar levels of resistance despite differences in antimicrobial usage. The levels of resistance in organic farm samples, where no antimicrobials were used, were very low by a culture-based method targeting fecal streptococci. However, when the same samples were analyzed with a molecular method detecting methylation of a specific nucleotide in the 23S rRNA that results in resistance to macrolides, lincosamides, and streptogramin B (MLSB), an unexpectedly high level of resistant rRNA (approximately 50%) was observed, suggesting that the fecal streptococci were not an appropriate target group to evaluate resistance in the overall microbial community and that background levels of MLSB resistance may be substantial. All of the feed samples tested, including those from the organic farm, contained tetracycline resistance genes. Generally, the same tetracycline resistance genes and frequency of detection were found in the manure and lagoon samples for each commercial farm. The levels of tetracycline and MLSB resistance remained high throughout the waste treatment systems, suggesting that the potential impact of land application of treated wastes and waste treatment by-products on environmental levels of resistance should be investigated further. PMID:17041160

  10. Influence of Sterilized Human Fecal Extract on the Sensitivity of Salmonella enterica ATCC 13076 and Listeria monocytogenes ATCC 15313 to Enrofloxacin.

    PubMed

    Ahn, Youngbeom; Stuckey, Ryan; Sung, Kidon; Rafii, Fatemeh; Cerniglia, Carl E

    2013-12-02

    There is much debate on whether continuous exposure of commensal bacteria and potential pathogens residing in the human intestinal tract to low levels of antimicrobial agents from treated food animals pose a public health concern. To investigate antimicrobial effects on bacteria under colonic conditions, we studied resistance development in Salmonella enterica and Listeria monocytogenes exposed to enrofloxacin in the presence of fecal extract. The bacteria were incubated at 37 °C in Mueller-Hinton broth, with and without 0.01~0.5 μg/mL enrofloxacin, in the presence and absence of sucrose, and with 1% or 2.5% filter-sterilized fecal extract, for three passages. In the second and third passages, only the bacteria incubated in the media containing sterilized fecal extract grew in 0.5 μg/mL of enrofloxacin. Fecal extract (1% and 2.5%) decreased the sensitivity of S. enterica to enrofloxacin in the medium containing the efflux pump inhibitors reserpine and carbonyl cyanide-m-chlorophenylhydrazone (CCCP) and affected the accumulation of ethidium bromide (EtBr) in this bacterium. Enrofloxacin (0.06 µg/mL) and fecal extract altered the composition of fatty acids in S. enterica and L. monocytogenes. We conclude that fecal extract decreased the susceptibilities of S. enterica and L. monocytogenes to concentrations of enrofloxacin higher than the MIC and resulted in rapid resistance selection.

  11. National Antimicrobial Resistance Monitoring System (NARMS) Program

    USDA-ARS?s Scientific Manuscript database

    The National Antimicrobial Resistance Monitoring System (NARMS) – Enteric Bacteria is a national public health surveillance system in the United States that tracks changes in the susceptibility of certain enteric bacteria to antimicrobial agents of human and veterinary medical importance. The NARMS ...

  12. Occurrence of antimicrobial resistant bacteria in healthy dogs and cats presented to private veterinary hospitals in southern Ontario: A preliminary study

    PubMed Central

    Murphy, Colleen; Reid-Smith, Richard J.; Prescott, John F.; Bonnett, Brenda N.; Poppe, Cornelis; Boerlin, Patrick; Weese, J. Scott; Janecko, Nicol; McEwen, Scott A.

    2009-01-01

    The prevalence and patterns of antimicrobial susceptibility of fecal Escherichia coli, Salmonella spp., extended β-lactamase producing E. coli (ESBL-E. coli), methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant Staphylococcus pseudintermedius (MRSP) were determined for healthy dogs (n = 188) and cats (n = 39) from veterinary hospitals in southern Ontario that had not had recent exposure to antimicrobials. The prevalence of antimicrobial resistance in E. coli was as follows: streptomycin (dogs — 17%, cats — 2%), ampicillin (dogs — 13%, cats — 4%), cephalothin (dogs — 13%, cats — < 1%), and tetracycline (dogs — 11%, cats — 2%). Eleven percent of dogs and 15% of cats had isolates that were resistant to at least 2 antimicrobials. Cephamycinase (CMY)-2 producing E. coli was cultured from 2 dogs. No Salmonella spp., ESBL-E. coli, MRSA, or MRSP isolates were recovered. The observed prevalence of resistance in commensal E. coli from this population was lower than that previously reported in companion animals, but a small percentage of dogs may be a reservoir for CMY-2 E. coli. PMID:20046603

  13. Containment of antimicrobial resistance due to use of antimicrobial agents in animals intended for food: WHO perspective.

    PubMed

    Aidara-Kane, A

    2012-04-01

    The use of antimicrobial agents in humans and food-producing animals has important consequences for human and animal health, as it can lead to the development of resistant bacteria (pathogens and/or commensals with resistance genes). Moreover, resistant bacteria in animals can be transferred to people--usually through the consumption of food, but also through direct contact with food-producing animals or through environmental spread. Ultimately, this can result in human infections with bacteria that are resistant to antimicrobial agents and that can therefore be difficult or impossible to cure. Of special concern is resistance to antimicrobial agents classified by the World Health Organization (WHO) as critically important for human medicine, such as fluoroquinolones, third- and fourth-generation cephalosporins, and macrolides. WHO encourages the agricultural, food, veterinary and health sectors to work together to eliminate the burden of antimicrobial resistance arising from the use of antimicrobial agents in food-producing animals. Joint efforts should be made to reduce the inappropriate use of antimicrobial agents (e.g. the use of antimicrobials as growth promoters) and limit the spread of bacteria resistant to antimicrobial agents. WHO will continueto address this issue in conjunction with the Food and Agriculture Organization of the United Nations, the World Organisation for Animal Health, the animal health/production industry and other important stakeholders. It will also continue to enhance the capacity of its Member States (through training courses and sentinel studies), particularly developing countries, to conduct integrated surveillance of antimicrobial use and resistance, to carry out risk assessments to support the selection of risk management options and to implement strategies for the containment of antimicrobial resistance.

  14. National Antimicrobial Resistance Monitoring System: Two Decades of Advancing Public Health Through Integrated Surveillance of Antimicrobial Resistance

    PubMed Central

    Tate, Heather; Plumblee, Jodie R.; Dessai, Uday; Whichard, Jean M.; Thacker, Eileen L.; Hale, Kis Robertson; Wilson, Wanda; Friedman, Cindy R.; Griffin, Patricia M.; McDermott, Patrick F.

    2017-01-01

    Abstract Drug-resistant bacterial infections pose a serious and growing public health threat globally. In this review, we describe the role of the National Antimicrobial Resistance Monitoring System (NARMS) in providing data that help address the resistance problem and show how such a program can have broad positive impacts on public health. NARMS was formed two decades ago to help assess the consequences to human health arising from the use of antimicrobial drugs in food animal production in the United States. A collaboration among the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, the United States Department of Agriculture, and state and local health departments, NARMS uses an integrated “One Health” approach to monitor antimicrobial resistance in enteric bacteria from humans, retail meat, and food animals. NARMS has adapted to changing needs and threats by expanding surveillance catchment areas, examining new isolate sources, adding bacteria, adjusting sampling schemes, and modifying antimicrobial agents tested. NARMS data are not only essential for ensuring that antimicrobial drugs approved for food animals are used in ways that are safe for human health but they also help address broader food safety priorities. NARMS surveillance, applied research studies, and outbreak isolate testing provide data on the emergence of drug-resistant enteric bacteria; genetic mechanisms underlying resistance; movement of bacterial populations among humans, food, and food animals; and sources and outcomes of resistant and susceptible infections. These data can be used to guide and evaluate the impact of science-based policies, regulatory actions, antimicrobial stewardship initiatives, and other public health efforts aimed at preserving drug effectiveness, improving patient outcomes, and preventing infections. Many improvements have been made to NARMS over time and the program will continue to adapt to address emerging resistance threats

  15. National Antimicrobial Resistance Monitoring System: Two Decades of Advancing Public Health Through Integrated Surveillance of Antimicrobial Resistance.

    PubMed

    Karp, Beth E; Tate, Heather; Plumblee, Jodie R; Dessai, Uday; Whichard, Jean M; Thacker, Eileen L; Hale, Kis Robertson; Wilson, Wanda; Friedman, Cindy R; Griffin, Patricia M; McDermott, Patrick F

    2017-10-01

    Drug-resistant bacterial infections pose a serious and growing public health threat globally. In this review, we describe the role of the National Antimicrobial Resistance Monitoring System (NARMS) in providing data that help address the resistance problem and show how such a program can have broad positive impacts on public health. NARMS was formed two decades ago to help assess the consequences to human health arising from the use of antimicrobial drugs in food animal production in the United States. A collaboration among the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, the United States Department of Agriculture, and state and local health departments, NARMS uses an integrated "One Health" approach to monitor antimicrobial resistance in enteric bacteria from humans, retail meat, and food animals. NARMS has adapted to changing needs and threats by expanding surveillance catchment areas, examining new isolate sources, adding bacteria, adjusting sampling schemes, and modifying antimicrobial agents tested. NARMS data are not only essential for ensuring that antimicrobial drugs approved for food animals are used in ways that are safe for human health but they also help address broader food safety priorities. NARMS surveillance, applied research studies, and outbreak isolate testing provide data on the emergence of drug-resistant enteric bacteria; genetic mechanisms underlying resistance; movement of bacterial populations among humans, food, and food animals; and sources and outcomes of resistant and susceptible infections. These data can be used to guide and evaluate the impact of science-based policies, regulatory actions, antimicrobial stewardship initiatives, and other public health efforts aimed at preserving drug effectiveness, improving patient outcomes, and preventing infections. Many improvements have been made to NARMS over time and the program will continue to adapt to address emerging resistance threats, changes in

  16. Salmonella Newport as Reported by the Animal Arm of the National Antimicrobial Resistance Monitoring System – Enteric Bacteria (NARMS) 1997-2007

    USDA-ARS?s Scientific Manuscript database

    Introduction: Since the early 1990’s there has been increasing awareness and concern regarding the development of antimicrobial resistance among bacteria of public health significance. Reports targeting zoonotic bacteria, and in particular Salmonella species, suggest that resistance is trending upw...

  17. Identification and Antimicrobial Resistance of Bacteria Isolated from Probiotic Products Used in Shrimp Culture.

    PubMed

    Noor Uddin, Gazi Md; Larsen, Marianne Halberg; Christensen, Henrik; Aarestrup, Frank M; Phu, Tran Minh; Dalsgaard, Anders

    2015-01-01

    Probiotics are increasingly used in aquaculture to control diseases and improve feed digestion and pond water quality; however, little is known about the antimicrobial resistance properties of such probiotic bacteria and to what extent they may contribute to the development of bacterial resistance in aquaculture ponds. Concerns have been raised that the declared information on probiotic product labels are incorrect and information on bacterial composition are often missing. We therefore evaluated seven probiotics commonly used in Vietnamese shrimp culture for their bacterial species content, phenotypic antimicrobial resistance and associated transferable resistance genes. The bacterial species was established by 16S rRNA sequence analysis of 125 representative bacterial isolates. MIC testing was done for a range of antimicrobials and whole genome sequencing of six multiple antimicrobial resistant Bacillus spp. used to identify resistance genes and genetic elements associated with horizontal gene transfer. Thirteen bacterial species declared on the probiotic products could not be identified and 11 non-declared Bacillus spp. were identified. Although our culture-based isolation and identification may have missed a few bacterial species present in the tested products this would represent minor bias, but future studies may apply culture independent identification methods like pyro sequencing. Only 6/60 isolates were resistant to more than four antimicrobials and whole genome sequencing showed that they contained macrolide (ermD), tetracycline (tetL), phenicol (fexA) and trimethoprim (dfrD, dfrG and dfrK) resistance genes, but not known structures associated with horizontal gene transfer. Probiotic bacterial strains used in Vietnamese shrimp culture seem to contribute with very limited types and numbers of resistance genes compared to the naturally occurring bacterial species in aquaculture environments. Approval procedures of probiotic products must be strengthened

  18. Ecological study on antimicrobial-resistant zoonotic bacteria transmitted by flies in cattle farms.

    PubMed

    Mohammed, Asmaa N; Abdel-Latef, Gihan K; Abdel-Azeem, Naglaa M; El-Dakhly, Khaled Mohamed

    2016-10-01

    Flies were qualitatively and quantitatively monitored on both livestock animals and the surrounding environment to investigate their role as a potential carrier for antimicrobial-resistant bacteria of zoonotic importance in cattle farms. This was done by the use of visual observations and animal photography; meanwhile, in the surrounding environment, flies were collected using sticky cards and then microscopically identified. Representative fly samples were cultured for bacterial isolation, biochemical identification, and then tested against common 12 antibiotics. The total average of dipterous flies in examined farms was 400.42 ± 6.2. Culicoides biting midges were the most common existing species (70.01 %) followed by house flies, stable flies, and mosquitoes (18.31, 7.74, and 3.91 %, respectively) at X (2) = 9.0, P < 0.05. The most predominant bacterial isolates were Escherichia coli (22.6 %), Staphylococcus aureus and Enterobacter (17.3 % each), coagulase-negative Staphylococci (CNS) (14.7 %), Klebsiella sp. (8 %), Salmonella spp. (6.7 %), and Shigella spp. and Proteus spp. (6.7 % each). The tested bacterial isolates were resistant to variant antibiotics used. S. aureus exhibited 100 % resistance to colistine. However, E. coli revealed 92.9 and 78.6 % resistance against tetracycline and colistine, respectively. Both Salmonella spp. and Shigella spp. were 100 % resistant to penicillin, and Klebsiella sp. had 100 % resistance to tetracycline. In conclusion, Culicoides biting midges and house flies could be considered as a potential carrier for multi-drug-resistant bacteria of zoonotic importance. Furthermore, cows' environment has an essential role in propagation and wide spread of antimicrobial-resistant bacterial pathogens.

  19. Distribution, Detection of Enterotoxigenic Strains and Antimicrobial Drug Susceptibility Patterns of Bacteroides Fragilis Group in Diarrheic and Non-Diarrheic Feces from Brazilian Infants

    PubMed Central

    Ferreira, Débora Paula; Silva, Vânia Lúcia; Guimarães, Danielle Aparecida; Coelho, Cíntia Marques; Zauli, Danielle Alves Gomes; Farias, Luiz Macêdo; Carvalho, Maria Auxiliadora Roque; Diniz, Claudio Galuppo

    2010-01-01

    Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0–5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic), and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children. PMID:24031535

  20. Synergistic effects of antimicrobial peptide DP7 combined with antibiotics against multidrug-resistant bacteria.

    PubMed

    Wu, Xiaozhe; Li, Zhan; Li, Xiaolu; Tian, Yaomei; Fan, Yingzi; Yu, Chaoheng; Zhou, Bailing; Liu, Yi; Xiang, Rong; Yang, Li

    2017-01-01

    Antibiotic-resistant bacteria present a great threat to public health. In this study, the synergistic effects of antimicrobial peptides (AMPs) and antibiotics on several multidrug-resistant bacterial strains were studied, and their synergistic effects on azithromycin (AZT)-resistance genes were analyzed to determine the relationships between antimicrobial resistance and these synergistic effects. A checkerboard method was used to evaluate the synergistic effects of AMPs (DP7 and CLS001) and several antibiotics (gentamicin, vancomycin [VAN], AZT, and amoxicillin) on clinical bacterial strains ( Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii , and Escherichia coli ). The AZT-resistance genes ( ermA, ermB, ermC, mefA , and msrA ) were identified in the resistant strains using quantitative polymerase chain reaction. For all the clinical isolates tested that were resistant to different antibiotics, DP7 had high antimicrobial activity (≤32 mg/L). When DP7 was combined with VAN or AZT, the effect was most frequently synergistic. When we studied the resistance genes of the AZT-resistant isolates, the synergistic effect of DP7-AZT occurred most frequently in highly resistant strains or strains carrying more than two AZT-resistance genes. A transmission electron microscopic analysis of the S. aureus strain synergistically affected by DP7-AZT showed no noteworthy morphological changes, suggesting that a molecular-level mechanism plays an important role in the synergistic action of DP7-AZT. AMP DP7 plus the antibiotic AZT or VAN is more effective, especially against highly antibiotic-resistant strains.

  1. ANTIMICROBIAL RESISTANCE AMONG ENTERIC BACTERIA ISOLATED FROM HUMAN AND ANIMAL WASTES AND IMPACTED SURFACE WATERS: COMPARISON WITH NARMS FINDINGS

    EPA Science Inventory

    Human infection with bacteria exhibiting mono or multiple antimicrobial resistance (MAR) has been a growing problem in the US, and studies have implicated livestock as a source of MAR bacteria primarily through foodborne transmission routes. However, waterborne transmission of...

  2. Antimicrobial drug use and resistance in dogs

    PubMed Central

    Prescott, John F.; Hanna, W. J. Brad; Reid-Smith, Richard; Drost, Kelli

    2002-01-01

    Fifteen years (1984–1998) of records from a Veterinary Teaching Hospital were analyzed to determine whether antimicrobial drug resistance in coagulase-positive Staphylococcus spp. (S. aureus, S. intermedius) isolated from clinical infections in dogs has increased, and whether there has been a change in the species of bacteria isolated from urinary tract infections in dogs. In coagulase-positive Staphylococcus spp., a complex pattern showing both increases and decreases of resistance to different classes of antimicrobial drugs was observed, reflecting the changing use of different antimicrobial drug classes in the hospital over a similar period (1990–1999). In canine urinary tract infections identified from 1984 to 1998, an increase in the incidence of multiresistant Enterococcus spp. was apparent, with marginal increases also in incidence in Enterobacter spp. and in Pseudomonas aeruginosa, both of which, like Enterococcus spp., are innately antimicrobial-resistant bacteria. A survey of directors of veterinary teaching hospitals in Canada and the United States identified only 3 hospitals that had any policy on use of “last resort” antimicrobial drugs (amikacin, imipenem, vancomycin). Evidence is briefly reviewed that owners may be at risk when dogs are treated with antimicrobial drugs, as well as evidence that some resistant bacteria may be acquired by dogs as a result of antimicrobial drug use in agriculture. Based in part on gaps in our knowledge, recommendations are made on prudent use of antimicrobial drugs in companion animals, as well as on the need to develop science-based infection control programs in veterinary hospitals. PMID:11842592

  3. Bisphosphocins: novel antimicrobials for enhanced killing of drug-resistant and biofilm-forming bacteria.

    PubMed

    Wong, Jonathan P; DiTullio, Paul; Parkinson, Steve

    2015-01-01

    The global prevalence of antibiotic resistance and the threat posed by drug-resistant superbugs are a leading challenge confronting modern medicine in the 21st century. However, the progress on the development of novel antibiotics to combat this problem is severely lagging. A more concerted effort to develop novel therapeutic agents with robust activity and unique mechanisms of action will be needed to overcome the problem of drug resistance. Furthermore, biofilm forming bacteria are known to be increasingly resistant to the actions of antibiotics and are a leading cause of mortality or morbidity in nosocomial infections. Bisphosphocins (also scientifically known as nubiotics) are novel small protonated deoxynucleotide molecules, and exert their antibacterial activity by depolarization of the bacterial cell membrane, causing bacterial cell death. Bisphosphocins may represent an effective weapon against antibiotic-resistant and biofilm-forming pathogenic bacteria. Preclinical efficacy studies in animals have shown that the compounds are safe and, efficacious against various bacterial infections, including drug-resistant pathogens. In vitro biochemical analysis confirmed that the bactericidal activity of bisphosphocins is mediated by depolarization of the bacterial cell membrane, and these compounds are better able to penetrate through bacterial biofilm and kill the biofilm encased bacteria. This article will cover the structure, mode of action, safety, efficacy and the current state of development of bisphosphocins. Together, the information presented here will present a strong case for bisphosphocins to be considered for use as new weapons to complement the existing arsenal of antimicrobial drugs and as a first line defence against drug-resistant and biofilm-forming bacteria.

  4. Effect of Antimicrobial Dosage Regimen on Salmonella and Escherichia coli Isolates from Feeder Swine▿

    PubMed Central

    Wagner, Bruce A.; Straw, Barbara E.; Fedorka-Cray, Paula J.; Dargatz, David A.

    2008-01-01

    A body of evidence exists that suggests that antimicrobial use in food animals leads to resistance in both pathogenic and commensal bacteria. This study focused on the impact of three different antimicrobial regimes (low-level continuous, pulse, and no antimicrobial) for two antimicrobials (chlortetracycline and tylosin) on the presence of Salmonella spp. and on the prevalence of antimicrobial resistance of both Salmonella spp. and nonspecific Escherichia coli in fecal samples from feeder swine. The prevalence of fecal samples positive for Salmonella spp. significantly decreased between the samples taken at feeder placement compared to samples taken when the animals were close to market weight. Differences in resistance of Salmonella spp. did not appear to be influenced by dosing treatment including the control. Analysis of antimicrobial resistance examining both susceptibility and resistance, as well as MIC outcomes, demonstrated that only resistance to cephalothin increased in E. coli under the pulse chlortetracycline treatment. These results suggest that the dosing regimes examined in this study did not lead to an increase in either the prevalence of Salmonella spp. or the prevalence of antimicrobial resistance in isolates of Salmonella spp. or E. coli. PMID:18223115

  5. Therapeutic Potential of a Scorpion Venom-Derived Antimicrobial Peptide and Its Homologs Against Antibiotic-Resistant Gram-Positive Bacteria.

    PubMed

    Liu, Gaomin; Yang, Fan; Li, Fangfang; Li, Zhongjie; Lang, Yange; Shen, Bingzheng; Wu, Yingliang; Li, Wenxin; Harrison, Patrick L; Strong, Peter N; Xie, Yingqiu; Miller, Keith; Cao, Zhijian

    2018-01-01

    The alarming rise in the prevalence of antibiotic resistance among pathogenic bacteria poses a unique challenge for the development of effective therapeutic agents. Antimicrobial peptides (AMPs) have attracted a great deal of attention as a possible solution to the increasing problem of antibiotic-resistant bacteria. Marcin-18 was identified from the scorpion Mesobuthus martensii at both DNA and protein levels. The genomic sequence revealed that the marcin-18 coding gene contains a phase-I intron with a GT-AG splice junction located in the DNA region encoding the N -terminal part of signal peptide. The peptide marcin-18 was also isolated from scorpion venom. A protein sequence homology search revealed that marcin-18 shares extremely high sequence identity to the AMPs meucin-18 and megicin-18. In vitro , chemically synthetic marcin-18 and its homologs (meucin-18 and megicin-18) showed highly potent inhibitory activity against Gram-positive bacteria, including some clinical antibiotic-resistant strains. Importantly, in a mouse acute peritonitis model, these peptides significantly decreased the bacterial load in ascites and rescued nearly all mice heavily infected with clinical methicillin-resistant Staphylococcus aureus from lethal bacteremia. Peptides exerted antimicrobial activity via a bactericidal mechanism and killed bacteria through membrane disruption. Taken together, marcin-18 and its homologs have potential for development as therapeutic agents for treating antibiotic-resistant, Gram-positive bacterial infections.

  6. The US national antimicrobial resistance monitoring system.

    PubMed

    Gilbert, Jeffrey M; White, David G; McDermott, Patrick F

    2007-10-01

    The use of antimicrobial agents in food animals can select for resistant bacterial pathogens that may be transmitted to humans via the commercial meat supply. In the USA, the FDA's Center for Veterinary Medicine regulatory duties require a determination that antimicrobial drugs are safe and effective for use in food animals. In addition, a qualitative assessment of risks to human health from antimicrobial resistance requires development. This risk assessment process is supported by data generated by the FDA's National Antimicrobial Resistance Monitoring System (NARMS) for enteric bacteria. NARMS data on antimicrobial susceptibility among Salmonella, Campylobacter, Escherichia coli and Enterococcus is collected. Research activities defining the genetic bases of resistance helps to understand the potential public health risks posed by the spread of antimicrobial resistance from food animal antimicrobial use. These activities help insure that antimicrobials are used judiciously to promote human and animal health.

  7. Diversity, abundance, and possible sources of fecal bacteria in the Yangtze River.

    PubMed

    Sun, Haohao; He, Xiwei; Ye, Lin; Zhang, Xu-Xiang; Wu, Bing; Ren, Hongqiang

    2017-03-01

    The fecal bacteria in natural waters may pose serious risks on human health. Although many source tracking methods have been developed and used to determine the possible sources of the fecal pollution, little is known about the overall diversity and abundance of fecal bacterial community in natural waters. In this study, a method based on fecal bacterial sequence library was introduced to evaluate the fecal bacterial profile in the Yangtze River (Nanjing section). Our results suggested that the Yangtze River water harbors diverse fecal bacteria. Fifty-eight fecal operational taxonomic units (97% identity level) were detected in the Yangtze River water samples and the relative abundance of fecal bacteria in these samples ranged from 0.1 to 8%. It was also found that the relative abundances of the fecal bacteria in locations near to the downstream of wastewater treatment plants were obviously higher than those in other locations. However, the high abundance of fecal bacteria could decrease to the normal level in 2~4 km in the river due to degradation or dilution, and the overall fecal bacteria level changed little when the Yangtze River flew through the Nanjing City. Moreover, the fecal bacteria in the Yangtze River water were found to be highly associated (Spearman rho = 0.804, P < 0.001) with the potential pathogenic bacteria. Collectively, the findings in this study reveal the diversity, abundance, and possible sources of fecal bacteria in the Yangtze River and advance our understandings of the fecal bacteria community in the natural waters.

  8. Frequency of resistance in obligate anaerobic bacteria isolated from dogs, cats, and horses to antimicrobial agents.

    PubMed

    Lawhon, S D; Taylor, A; Fajt, V R

    2013-11-01

    Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). The MICs of amoxicillin with clavulanate, ampicillin, chloramphenicol, metronidazole, and penicillin were determined using a gradient endpoint method for anaerobes. Isolates collected at necropsy were not tested for antimicrobial susceptibility unless so requested by the clinician. There were 1/145 isolates tested that were resistant to amoxicillin-clavulanate (resistance breakpoint ≥ 16/8 μg/ml), 7/77 isolates tested were resistant to ampicillin (resistance breakpoint ≥ 2 μg/ml), 4/242 isolates tested were resistant to chloramphenicol (resistance breakpoint ≥ 32 μg/ml), 12/158 isolates tested were resistant to clindamycin (resistance breakpoint ≥ 8 μg/ml), 10/247 isolates tested were resistant to metronidazole (resistance breakpoint ≥ 32 μg/ml), and 54/243 isolates tested were resistant to penicillin (resistance breakpoint ≥ 2 μg/ml). These data suggest that anaerobes are generally susceptible to antimicrobial drugs in vitro.

  9. Isolation and Structural Elucidation of Brevibacillin, an Antimicrobial Lipopeptide from Brevibacillus laterosporus That Combats Drug-Resistant Gram-Positive Bacteria.

    PubMed

    Yang, Xu; Huang, En; Yuan, Chunhua; Zhang, Liwen; Yousef, Ahmed E

    2016-05-01

    A new environmental bacterial strain exhibited strong antimicrobial characteristics against methicillin-resistant Staphylococcus aureus, vancomycin-resistant strains of Enterococcus faecalis and Lactobacillus plantarum, and other Gram-positive bacteria. The producer strain, designated OSY-I1, was determined to be Brevibacillus laterosporusvia morphological, biochemical, and genetic analyses. The antimicrobial agent was extracted from cells of OSY-I1 with isopropanol, purified by high-performance liquid chromatography, and structurally analyzed using mass spectrometry (MS) and nuclear magnetic resonance (NMR). The MS and NMR results, taken together, uncovered a linear lipopeptide consisting of 13 amino acids and an N-terminal C6 fatty acid (FA) chain, 2-hydroxy-3-methylpentanoic acid. The lipopeptide (FA-Dhb-Leu-Orn-Ile-Ile-Val-Lys-Val-Val-Lys-Tyr-Leu-valinol, where Dhb is α,β-didehydrobutyric acid and valinol is 2-amino-3-methyl-1-butanol) has a molecular mass of 1,583.0794 Da and contains three modified amino acid residues: α,β-didehydrobutyric acid, ornithine, and valinol. The compound, designated brevibacillin, was determined to be a member of a cationic lipopeptide antibiotic family. In addition to its potency against drug-resistant bacteria, brevibacillin also exhibited low MICs (1 to 8 μg/ml) against selected foodborne pathogenic and spoilage bacteria, such as Listeria monocytogenes,Bacillus cereus, and Alicyclobacillus acidoterrestris Purified brevibacillin showed no sign of degradation when it was held at 80 °C for 60 min, and it retained at least 50% of its antimicrobial activity when it was held for 22 h under acidic or alkaline conditions. On the basis of these findings, brevibacillin is a potent antimicrobial lipopeptide which is potentially useful to combat drug-resistant bacterial pathogens and foodborne pathogenic and spoilage bacteria. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  10. Antimicrobial activity of polyphenol-rich fractions from Sida alba L. (Malvaceae) against co-trimoxazol-resistant bacteria strains.

    PubMed

    Konaté, Kiessoun; Hilou, Adama; Mavoungou, Jacques François; Lepengué, Alexis Nicaise; Souza, Alain; Barro, Nicolas; Datté, Jacques Y; M'batchi, Bertrand; Nacoulma, Odile Germaine

    2012-02-24

    The increased resistance of microorganisms to the currently used antimicrobials has lead to the evaluation of other agents that might have antimicrobial activity. Medicinal plants are sources of phytochemicals which are able to initiate different biological activities including antimicrobials In vitro antibacterial (MIC, MBC and time-kill studies) of polyphenol-rich fractions from Sida alba L. (Malvaceae) was assessed using ten bacteria strains (Gram-negative and Gram-positive). All test bacteria were susceptible to the polyphenol-rich fractions. Time-kill results showed that after 5 h exposition there was no viable microorganism in the initial inoculum and the effect of polyphenol-rich fractions was faster on Enterococcus faecalis (Gram-positive bacterium) comparatively to the other bacteria strains. The data analysis indicates that the tested of polyphenol-rich fractions has significant effects when compared with the standard antibiotic. These results therefore justify the traditional use of sida alba L., alone or in combination with other herbs to treat bacterial infections.

  11. Antimicrobial activity of polyphenol-rich fractions from Sida alba L. (Malvaceae) against co-trimoxazol-resistant bacteria strains

    PubMed Central

    2012-01-01

    Background The increased resistance of microorganisms to the currently used antimicrobials has lead to the evaluation of other agents that might have antimicrobial activity. Medicinal plants are sources of phytochemicals which are able to initiate different biological activities including antimicrobials Materials and methods In vitro antibacterial (MIC, MBC and time-kill studies) of polyphenol-rich fractions from Sida alba L. (Malvaceae) was assessed using ten bacteria strains (Gram-negative and Gram-positive). Results All test bacteria were susceptible to the polyphenol-rich fractions. Time-kill results showed that after 5 h exposition there was no viable microorganism in the initial inoculum and the effect of polyphenol-rich fractions was faster on Enterococcus faecalis (Gram-positive bacterium) comparatively to the other bacteria strains. Conclusion The data analysis indicates that the tested of polyphenol-rich fractions has significant effects when compared with the standard antibiotic. These results therefore justify the traditional use of sida alba L., alone or in combination with other herbs to treat bacterial infections. PMID:22364123

  12. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance.

    PubMed

    Magiorakos, A-P; Srinivasan, A; Carey, R B; Carmeli, Y; Falagas, M E; Giske, C G; Harbarth, S; Hindler, J F; Kahlmeter, G; Olsson-Liljequist, B; Paterson, D L; Rice, L B; Stelling, J; Struelens, M J; Vatopoulos, A; Weber, J T; Monnet, D L

    2012-03-01

    Many different definitions for multidrug-resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant (PDR) bacteria are being used in the medical literature to characterize the different patterns of resistance found in healthcare-associated, antimicrobial-resistant bacteria. A group of international experts came together through a joint initiative by the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC), to create a standardized international terminology with which to describe acquired resistance profiles in Staphylococcus aureus, Enterococcus spp., Enterobacteriaceae (other than Salmonella and Shigella), Pseudomonas aeruginosa and Acinetobacter spp., all bacteria often responsible for healthcare-associated infections and prone to multidrug resistance. Epidemiologically significant antimicrobial categories were constructed for each bacterium. Lists of antimicrobial categories proposed for antimicrobial susceptibility testing were created using documents and breakpoints from the Clinical Laboratory Standards Institute (CLSI), the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the United States Food and Drug Administration (FDA). MDR was defined as acquired non-susceptibility to at least one agent in three or more antimicrobial categories, XDR was defined as non-susceptibility to at least one agent in all but two or fewer antimicrobial categories (i.e. bacterial isolates remain susceptible to only one or two categories) and PDR was defined as non-susceptibility to all agents in all antimicrobial categories. To ensure correct application of these definitions, bacterial isolates should be tested against all or nearly all of the antimicrobial agents within the antimicrobial categories and selective reporting and suppression of results should be avoided. © 2011 European Society of Clinical Microbiology and Infectious Diseases. No claim to original US government works.

  13. Resistance profiles to antimicrobial agents in bacteria isolated from acute endodontic infections: systematic review and meta-analysis.

    PubMed

    Lang, Pauline M; Jacinto, Rogério C; Dal Pizzol, Tatiane S; Ferreira, Maria Beatriz C; Montagner, Francisco

    2016-11-01

    Infected root canal or acute apical abscess exudates can harbour several species, including Fusobacterium, Porphyromonas, Prevotella, Parvimonas, Streptococcus, Treponema, Olsenella and not-yet cultivable species. A systematic review and meta-analysis was performed to assess resistance rates to antimicrobial agents in clinical studies that isolated bacteria from acute endodontic infections. Electronic databases and the grey literature were searched up to May 2015. Clinical studies in humans evaluating the antimicrobial resistance of primary acute endodontic infection isolates were included. PRISMA guidelines were followed. A random-effect meta-analysis was employed. The outcome was described as the pooled resistance rates for each antimicrobial agent. Heterogeneity and sensitivity analyses were performed. Subgroup analyses were conducted based upon report or not of the use of antibiotics prior to sampling as an exclusion factor (subgroups A and B, respectively). Data from seven studies were extracted. Resistance rates for 15 different antimicrobial agents were evaluated (range, 3.5-40.0%). Lower resistance rates were observed for amoxicillin/clavulanic acid and amoxicillin; higher resistance rates were detected for tetracycline. Resistance rates varied according to previous use of an antimicrobial agent as demonstrated by the subgroup analyses. Heterogeneity was observed for the resistance profiles of penicillin G in subgroup A and for amoxicillin, clindamycin, metronidazole and tetracycline in subgroup B. Sensitivity analyses demonstrated that resistance rates changed for metronidazole, clindamycin, tetracycline and amoxicillin. These findings suggest that clinical isolates had low resistance to β-lactams. Further well-designed studies are needed to clarify whether the differences in susceptibility among the antimicrobial agents may influence clinical responses to treatment. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights

  14. Finding Novel Antibiotic Substances from Medicinal Plants - Antimicrobial Properties of Nigella Sativa Directed against Multidrug-resistant Bacteria.

    PubMed

    Bakal, Seher Nancy; Bereswill, Stefan; Heimesaat, Markus M

    2017-03-01

    The progressive rise in multidrug-resistant (MDR) bacterial strains poses serious problems in the treatment of infectious diseases. While the number of newly developed antimicrobial compounds has greatly fallen, the resistance of pathogens against commonly prescribed drugs is further increasing. This rise in resistance illustrates the need for developing novel therapeutic and preventive antimicrobial options. The medicinal herb Nigella sativa and its derivatives constitute promising candidates. In a comprehensive literature survey (using the PubMed data base), we searched for publications on the antimicrobial effects of N. sativa particularly directed against MDR bacterial strains. In vitro studies published between 2000 and 2015 revealed that N. sativa exerted potent antibacterial effects against both Gram-positive and Gram-negative species including resistant strains. For instance, N. sativa inhibited the growth of bacteria causing significant gastrointestinal morbidity such as Salmonella, Helicobacter pylori , and Escherichia coli . However, Listeria monocytogenes and Pseudomonas aeruginosa displayed resistance against black cumin seed extracts. In conclusion, our literature survey revealed potent antimicrobial properties of N. sativa against MDR strains in vitro that should be further investigated in order to develop novel therapeutic perspectives for combating infectious diseases particularly caused by MDR strains.

  15. Bacterial strategies of resistance to antimicrobial peptides.

    PubMed

    Joo, Hwang-Soo; Fu, Chih-Iung; Otto, Michael

    2016-05-26

    Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. © 2016 The Author(s).

  16. The use of minimum selectable concentrations (MSCs) for determining the selection of antimicrobial resistant bacteria.

    PubMed

    Khan, Sadia; Beattie, Tara K; Knapp, Charles W

    2017-03-01

    The use of antimicrobial compounds is indispensable in many industries, especially drinking water production, to eradicate microorganisms. However, bacterial growth is not unusual in the presence of disinfectant concentrations that would be typically lethal, as bacterial populations can develop resistance. The common metric of population resistance has been based on the Minimum Inhibitory Concentration (MIC), which is based on bacteria lethality. However, sub-lethal concentrations may also select for resistant bacteria due to the differences in bacterial growth rates. This study determined the Minimal Selective Concentrations (MSCs) of bacterial populations exposed to free chlorine and monochloramine, representing a metric that possibly better reflects the selective pressures occurring at lower disinfectant levels than MIC. Pairs of phylogenetically similar bacteria were challenged to a range of concentrations of disinfectants. The MSCs of free chlorine and monochloramine were found to range between 0.021 and 0.39 mg L -1 , which were concentrations 1/250 to 1/5 than the MICs of susceptible bacteria (MIC susc ). This study indicates that sub-lethal concentrations of disinfectants could result in the selection of resistant bacterial populations, and MSCs would be a more sensitive indicator of selective pressure, especially in environmental systems.

  17. Detection of antimicrobial resistance-associated proteins by titanium dioxide-facilitated intact bacteria mass spectrometry† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc04089j

    PubMed Central

    Zhu, Yingdi; Gasilova, Natalia; Jović, Milica; Qiao, Liang; Liu, Baohong; Lovey, Lysiane Tissières; Pick, Horst

    2018-01-01

    Titanium dioxide-modified target plates were developed to enhance intact bacteria analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The plates were designed to photocatalytically destroy the bacterial envelope structure and improve the ionization efficiency of intracellular components, thereby promoting the measurable mass range and the achievable detection sensitivity. Accordingly, a method for rapid detection of antimicrobial resistance-associated proteins, conferring bacterial resistance against antimicrobial drugs, was established by mass spectrometric fingerprinting of intact bacteria without the need for any sample pre-treatment. With this method, the variations in resistance proteins’ expression levels within bacteria were quickly measured from the relative peak intensities. This approach of resistance protein detection directly from intact bacteria by mass spectrometry is useful for fast discrimination of antimicrobial-resistant bacteria from their non-resistant counterparts whilst performing species identification. Also, it could be used as a rapid and convenient way for initial determination of the underlying resistance mechanisms. PMID:29719694

  18. Fecal-indicator bacteria in streams alonga gradient of residential development

    USGS Publications Warehouse

    Frenzel, Steven A.; Couvillion, Charles S.

    2002-01-01

    Fecal-indicator bacteria were sampled at 14 stream sites in Anchorage, Alaska, USA, as part of a study to determine the effects of urbanization on water quality. Population density in the subbasins sampled ranged from zero to 1,750 persons per square kilometer. Higher concentrations of fecal-coliform, E. coli, and enterococci bacteria were measured at the most urbanized sites. Although fecal-indicator bacteria concentrations were higher in summer than in winter, seasonal differences in bacteria concentrations generally were not significant. Areas served by sewer systems had significantly higher fecal-indicator bacteria concentrations than did areas served by septic systems. The areas served by sewer systems also had storm drains that discharged directly to the streams, whereas storm sewers were not present in the areas served by septic systems. Fecal-indicator bacteria concentrations were highly variable over a two-day period of stable streamflow, which may have implications for testing of compliance to water-quality standards.

  19. Antimicrobial resistance mechanisms among Campylobacter.

    PubMed

    Wieczorek, Kinga; Osek, Jacek

    2013-01-01

    Campylobacter jejuni and Campylobacter coli are recognized as the most common causative agents of bacterial gastroenteritis in the world. Humans most often become infected by ingesting contaminated food, especially undercooked chicken, but also other sources of bacteria have been described. Campylobacteriosis is normally a self-limiting disease. Antimicrobial treatment is needed only in patients with more severe disease and in those who are immunologically compromised. The most common antimicrobial agents used in the treatment of Campylobacter infections are macrolides, such as erythromycin, and fluoroquinolones, such as ciprofloxacin. Tetracyclines have been suggested as an alternative choice in the treatment of clinical campylobacteriosis but in practice are not often used. However, during the past few decades an increasing number of resistant Campylobacter isolates have developed resistance to fluoroquinolones and other antimicrobials such as macrolides, aminoglycosides, and beta-lactams. Trends in antimicrobial resistance have shown a clear correlation between use of antibiotics in the veterinary medicine and animal production and resistant isolates of Campylobacter in humans. In this review, the patterns of emerging resistance to the antimicrobial agents useful in treatment of the disease are presented and the mechanisms of resistance to these drugs in Campylobacter are discussed.

  20. Antimicrobial resistance in Saudi Arabia

    PubMed Central

    Zowawi, Hosam M.

    2016-01-01

    Antimicrobial resistance (AMR) is increasingly being highlighted as an urgent public and animal health issue worldwide. This issue is well demonstrated in bacteria that are resistant to last-line antibiotics, suggesting a future with untreatable infections. International agencies have suggested combating strategies against AMR. Saudi Arabia has several challenges that can stimulate the emergence and spread of multidrug-resistant bacteria. Tackling these challenges need efforts from multiple sectors to successfully control the spread and emergence of AMR in the country. Actions should include active surveillance to monitor the emergence and spread of AMR. Infection prevention and control precautions should also be optimized to limit further spread. Raising awareness is essential to limit inappropriate antibiotics use, and the antibiotic stewardship programs in hospital settings, outpatients, and community pharmacies, should regulate the ongoing use of antimicrobials. PMID:27570847

  1. Resistance of Bacteria to Biocides.

    PubMed

    Maillard, Jean-Yves

    2018-04-01

    Biocides and formulated biocides are used worldwide for an increasing number of applications despite tightening regulations in Europe and in the United States. One concern is that such intense usage of biocides could lead to increased bacterial resistance to a product and cross-resistance to unrelated antimicrobials including chemotherapeutic antibiotics. Evidence to justify such a concern comes mostly from the use of health care-relevant bacterial isolates, although the number of studies of the resistance characteristics of veterinary isolates to biocides have increased the past few years. One problem remains the definition of "resistance" and how to measure resistance to a biocide. This has yet to be addressed globally, although the measurement of resistance is becoming more pressing, with regulators both in Europe and in the United States demanding that manufacturers provide evidence that their biocidal products will not impact on bacterial resistance. Alongside in vitro evidence of potential antimicrobial cross-resistance following biocide exposure, our understanding of the mechanisms of bacterial resistance and, more recently, our understanding of the effect of biocides to induce a mechanism(s) of resistance in bacteria has improved. This article aims to provide an understanding of the development of antimicrobial resistance in bacteria following a biocide exposure. The sections provide evidence of the occurrence of bacterial resistance and its mechanisms of action and debate how to measure bacterial resistance to biocides. Examples pertinent to the veterinary field are used where appropriate.

  2. Sucralose Increases Antimicrobial Resistance and Stimulates Recovery of Escherichia coli Mutants.

    PubMed

    Qu, Yilin; Li, Rongyan; Jiang, Mingshan; Wang, Xiuhong

    2017-07-01

    Because of heavy use of antimicrobials, antimicrobial resistance in bacteria has become of great concern. The effect of some widely used food additives such as sucralose on bacteria in the gut and the environment has also drawn increasing attention. In this study, we investigated the interaction between antimicrobials and sucralose impacting antimicrobial resistance and mutation of Escherichia coli (E. coli). To examine antimicrobial resistance and mutation frequency, different subinhibitory concentrations of sucralose were added to cultures of E.coli BW25113 that were then treated with antimicrobials, oxolinic acid, or moxifloxacin. Then the E.coli were assayed for bacterial survival and recovery of mutants resistant to an unrelated antimicrobial, rifampicin. Pre-treatment of E.coli BW25113 with 1/2 minimal inhibitory concentration (MIC) of sucralose increased the survival rate in oxolinic acid or moxifloxacin. A 1/3 MIC of sucralose increased rifampicin-resistant mutation rate of E.coli BW25113 after 72 h, while rifampicin-resistant mutation rate was increased when co-treated with 1/8 MIC, 1/4 MIC, 1/3 MIC sucralose, and oxolinic acid after 24 h. Sucralose can increase the antimicrobial resistance and mutation frequency of E.coli to some antimicrobials.

  3. Pathogen prevalence and influence of composted dairy manure application on antimicrobial resistance profiles of commensal soil bacteria.

    PubMed

    Edrington, Tom S; Fox, William E; Callaway, Todd R; Anderson, Robin C; Hoffman, Dennis W; Nisbet, David J

    2009-03-01

    Composting manure, if done properly, should kill pathogenic bacteria such as Salmonella and Escherichia coli O157:H7, providing for an environmentally safe product. Over a 3-year period, samples of composted dairy manure, representing 11 composting operations (two to six samples per producer; 100 total samples), were screened for Salmonella and E. coli O157:H7 and were all culture negative. Nonpathogenic bacteria were cultured from these compost samples that could theoretically facilitate the spread of antimicrobial resistance from the dairy to compost application sites. Therefore, we collected soil samples (three samples per plot; 10 plots/treatment; 90 total samples) from rangeland that received either composted dairy manure (CP), commercial fertilizer (F), or no treatment (control, CON). Two collections were made appoximately 2 and 7 months following treatment application. Soil samples were cultured for Pseudomonas and Enterobacter and confirmed isolates subjected to antimicrobial susceptibility testing. Three species of Enterobacter (cloacae, 27 isolates; aeroginosa, two isolates; sakazakii, one isolate) and two species of Pseudomonas (aeruginosa, 11 isolates; putida, seven isolates) were identified. Five Enterobacter isolates were resistant to ampicillin and one isolate was resistant to spectinomycin. All Pseudomonas isolates were resistant to ampicillin, ceftiofur, florfenicol, sulphachloropyridazine, sulphadimethoxine, and trimethoprim/sulfamethoxazole and most isolates were resistant to chlortetracycline and spectinomycin. Pseudomonas isolates were resistant to an average of 8.6, 7.9, and 8 antibiotics for CON, CP, and F treatments, respectively. No treatment differences were observed in antimicrobial resistance patterns in any of the soil isolates examined. Results reported herein support the use of composted dairy manure as an environmentally friendly soil amendment.

  4. Pilot Study of Antimicrobial Resistance in Northern Bobwhites (Colinus virginianus).

    PubMed

    Zhang, Michael; Shen, Zhenyu; Rollins, Dale; Fales, William; Zhang, Shuping

    2017-09-01

    Antimicrobial resistance (AMR) is an important issue for both wildlife conservation and public health. The purpose of this study was to screen for AMR in fecal bacteria isolated from northern bobwhite (Colinus virginianus), a species that is an ecologically and economically important natural resource in the southern United States. The antimicrobial susceptibility profiles of 45 Escherichia coli isolates, 20 Enterococcus faecalis isolates, and 10 Enterococcus faecium isolates were determined using the Sensititer TM microbroth dilution minimum inhibitory concentration (MIC) plate, AVIAN1F. Overall, E. coli isolates had high MIC values for the following classes of antimicrobials: aminocoumarins, beta-lactams, lincosamides, macrolides, florfenicol, and sulfonamides. Enterococcus faecalis and E. faecium isolates had high MICs for aminocyclitols, aminoglycosides, beta-lactams, lincosamides, and sulfonamides. Enterococcus faecalis isolates also showed high MICs for aminocoumarins, while E. faecium isolates had high MICs for trimethoprim/sulfamethoxazole and tetracycline. Based on available veterinary interpretive criteria, 15% and 33% of E. coli isolates were resistant to sulphathiazole and sulphadimethoxine, respectively. Intermediate susceptibility to florfenicol was seen with 17.8% of E. coli isolates. Twenty percent of E. faecalis and 80% of E. faecium isolates were resistant to high-concentration streptomycin. One third of E. faecalis and 70% of E. faecium isolates were intermediately susceptible to erythromycin. Ten percent of E. faecium isolates were resistant to tetracycline and oxytetracycline. A comparison of available MIC suggests that AMR in wild bobwhite is less severe than in domestic poultry. Further investigation is needed to determine the source of AMR in wild bobwhite.

  5. Finding Novel Antibiotic Substances from Medicinal Plants – Antimicrobial Properties of Nigella Sativa Directed against Multidrug-resistant Bacteria

    PubMed Central

    Bakal, Seher Nancy; Bereswill, Stefan; Heimesaat, Markus M.

    2017-01-01

    The progressive rise in multidrug-resistant (MDR) bacterial strains poses serious problems in the treatment of infectious diseases. While the number of newly developed antimicrobial compounds has greatly fallen, the resistance of pathogens against commonly prescribed drugs is further increasing. This rise in resistance illustrates the need for developing novel therapeutic and preventive antimicrobial options. The medicinal herb Nigella sativa and its derivatives constitute promising candidates. In a comprehensive literature survey (using the PubMed data base), we searched for publications on the antimicrobial effects of N. sativa particularly directed against MDR bacterial strains. In vitro studies published between 2000 and 2015 revealed that N. sativa exerted potent antibacterial effects against both Gram-positive and Gram-negative species including resistant strains. For instance, N. sativa inhibited the growth of bacteria causing significant gastrointestinal morbidity such as Salmonella, Helicobacter pylori, and Escherichia coli. However, Listeria monocytogenes and Pseudomonas aeruginosa displayed resistance against black cumin seed extracts. In conclusion, our literature survey revealed potent antimicrobial properties of N. sativa against MDR strains in vitro that should be further investigated in order to develop novel therapeutic perspectives for combating infectious diseases particularly caused by MDR strains. PMID:28386474

  6. RNA-Based Methods Increase the Detection of Fecal Bacteria and Fecal Identifiers in Environmental Waters

    EPA Science Inventory

    We evaluated the use of qPCR RNA-based methods in the detection of fecal bacteria in environmental waters. We showed that RNA methods can increase the detection of fecal bacteria in multiple water matrices. The data suggest that this is a viable alternative for the detection of a...

  7. Antimicrobial Resistance in Asia: Current Epidemiology and Clinical Implications

    PubMed Central

    Kang, Cheol-In

    2013-01-01

    Antimicrobial resistance has become one of the most serious public health concerns worldwide. Although circumstances may vary by region or country, it is clear that some Asian countries are epicenters of resistance, having seen rapid increases in the prevalence of antimicrobial resistance of major bacterial pathogens. In these locations, however, the public health infrastructure to combat this problem is very poor. The prevalence rates of methicillin-resistant Staphylococcus aureus (MRSA), macrolide-resistant Streptococcus pneumoniae, and multidrug-resistant enteric pathogens are very high due to the recent emergence of extremely drug-resistant gram-negative bacilli in Asia. Because antimicrobial options for these pathogens are extremely limited, infections caused by antimicrobial-resistant bacteria are often associated with inappropriate antimicrobial therapy and poor clinical outcomes. Physicians should be aware of the current epidemiological status of resistance and understand the appropriate use of antimicrobial agents in clinical practice. This review focuses on describing the epidemiology and clinical implications of antimicrobial-resistant bacterial infections in Asian countries. PMID:24265947

  8. Antimicrobial use in aquaculture re-examined: its relevance to antimicrobial resistance and to animal and human health.

    PubMed

    Cabello, Felipe C; Godfrey, Henry P; Tomova, Alexandra; Ivanova, Larisa; Dölz, Humberto; Millanao, Ana; Buschmann, Alejandro H

    2013-07-01

    The worldwide growth of aquaculture has been accompanied by a rapid increase in therapeutic and prophylactic usage of antimicrobials including those important in human therapeutics. Approximately 80% of antimicrobials used in aquaculture enter the environment with their activity intact where they select for bacteria whose resistance arises from mutations or more importantly, from mobile genetic elements containing multiple resistance determinants transmissible to other bacteria. Such selection alters biodiversity in aquatic environments and the normal flora of fish and shellfish. The commonality of the mobilome (the total of all mobile genetic elements in a genome) between aquatic and terrestrial bacteria together with the presence of residual antimicrobials, biofilms, and high concentrations of bacteriophages where the aquatic environment may also be contaminated with pathogens of human and animal origin can stimulate exchange of genetic information between aquatic and terrestrial bacteria. Several recently found genetic elements and resistance determinants for quinolones, tetracyclines, and β-lactamases are shared between aquatic bacteria, fish pathogens, and human pathogens, and appear to have originated in aquatic bacteria. Excessive use of antimicrobials in aquaculture can thus potentially negatively impact animal and human health as well as the aquatic environment and should be better assessed and regulated. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

  9. Prevalence and antimicrobial resistance in Escherichia coli from food animals in Lagos, Nigeria

    USDA-ARS?s Scientific Manuscript database

    Foodborne bacteria are often associated with human infections; these infections can become more complicated to treat if the bacteria are also resistant to antimicrobials. In this study, prevalence, antimicrobial resistance, and genetic relatedness of Escherichia coli among food producing animals fr...

  10. Irrigation waters and pipe-based biofilms as sources for antibiotic-resistant bacteria.

    PubMed

    Blaustein, Ryan A; Shelton, Daniel R; Van Kessel, Jo Ann S; Karns, Jeffrey S; Stocker, Matthew D; Pachepsky, Yakov A

    2016-01-01

    The presence of antibiotic-resistant bacteria in environmental surface waters has gained recent attention. Wastewater and drinking water distribution systems are known to disseminate antibiotic-resistant bacteria, with the biofilms that form on the inner-surfaces of the pipeline as a hot spot for proliferation and gene exchange. Pipe-based irrigation systems that utilize surface waters may contribute to the dissemination of antibiotic-resistant bacteria in a similar manner. We conducted irrigation events at a perennial stream on a weekly basis for 1 month, and the concentrations of total heterotrophic bacteria, total coliforms, and fecal coliforms, as well as the concentrations of these bacterial groups that were resistant to ampicillin and tetracycline, were monitored at the intake water. Prior to each of the latter three events, residual pipe water was sampled and 6-in. sections of pipeline (coupons) were detached from the system, and biofilm from the inner-wall was removed and analyzed for total protein content and the above bacteria. Isolates of biofilm-associated bacteria were screened for resistance to a panel of seven antibiotics, representing five antibiotic classes. All of the monitored bacteria grew substantially in the residual water between irrigation events, and the biomass of the biofilm steadily increased from week to week. The percentages of biofilm-associated isolates that were resistant to antibiotics on the panel sometimes increased between events. Multiple-drug resistance was observed for all bacterial groups, most often for fecal coliforms, and the distributions of the numbers of antibiotics that the total coliforms and fecal coliforms were resistant to were subject to change from week to week. Results from this study highlight irrigation waters as a potential source for antibiotic-resistant bacteria, which can subsequently become incorporated into and proliferate within irrigation pipe-based biofilms.

  11. Macrolide Resistance in Microorganisms at Antimicrobial-Free Swine Farms▿

    PubMed Central

    Zhou, Zhi; Raskin, Lutgarde; Zilles, Julie L.

    2009-01-01

    To investigate the relationship between agricultural antimicrobial use and resistance, a variety of methods for quantification of macrolide-lincosamide-streptogramin B (MLSB) resistance were applied to organic swine farm manure samples. Fluorescence in situ hybridization was used to indirectly quantify the specific rRNA methylation resulting in MLSB resistance. Using this method, an unexpectedly high prevalence of ribosomal methylation and, hence, predicted MLSB resistance was observed in manure samples from two swine finisher farms that reported no antimicrobial use (37.6% ± 6.3% and 40.5% ± 5.4%, respectively). A culture-based method targeting relatively abundant clostridia showed a lower but still unexpectedly high prevalence of resistance at both farms (27.7% ± 11.3% and 11.7% ± 8.6%, respectively), while the prevalence of resistance in cultured fecal streptococci was low at both farms (4.0%). These differences in the prevalence of resistance across microorganisms suggest the need for caution when extrapolating from data obtained with indicator organisms. A third antimicrobial-free swine farm, a breeder-to-finisher operation, had low levels of MLSB resistance in manure samples with all methods used (<9%). Tetracycline antimicrobials were detected in manure samples from one of the finisher farms and may provide a partial explanation for the high level of MLSB resistance. Taken together, these findings highlight the need for a more fundamental understanding of the relationship between antimicrobial use and the prevalence of antimicrobial resistance. PMID:19633121

  12. Prevalence and Antimicrobial Resistance of Enterococci Isolated from Retail Meats in the United States, 2002 to 2014.

    PubMed

    Tyson, Gregory H; Nyirabahizi, Epiphanie; Crarey, Emily; Kabera, Claudine; Lam, Claudia; Rice-Trujillo, Crystal; McDermott, Patrick F; Tate, Heather

    2018-01-01

    Bacteria of the genus Enterococcus are important human pathogens that are frequently resistant to a number of clinically important antibiotics. They are also used as markers of animal fecal contamination of human foods and are employed as sentinel organisms for tracking trends in resistance to antimicrobials with Gram-positive activity. As part of the National Antimicrobial Resistance Monitoring System (NARMS), we evaluated several retail meat commodities for the presence of enterococci from 2002 to 2014, and we found 92.0% to be contaminated. The majority of isolates were either Enterococcus faecalis (64.0%) or Enterococcus faecium (28.6%), and the antimicrobial resistance of each isolate was assessed by broth microdilution. The resistance prevalences for several drugs, including erythromycin and gentamicin, were significantly higher among poultry isolates, compared to retail beef or pork isolates. None of the isolates was resistant to the clinically important human drug vancomycin, only 1 isolate was resistant to linezolid, and resistance to tigecycline was below 1%. In contrast, a majority of both E. faecalis (67.5%) and E. faecium (53.7%) isolates were resistant to tetracycline. Overall, the robust NARMS testing system employed consistent sampling practices and methods throughout the testing period, with the only significant trend in resistance prevalence being decreased E. faecium resistance to penicillin. These data provide excellent baseline levels of resistance that can be used to measure future changes in resistance prevalence that may result from alterations in the use of antimicrobials in food animal production. IMPORTANCE Enterococci, including E. faecalis and E. faecium , are present in the guts of food-producing animals and are used as a measure of fecal contamination of meat. We used the large consistent sampling methods of NARMS to assess the prevalence of Enterococcus strains isolated from retail meats, and we found over 90% of meats to be

  13. Antimicrobial utilization and bacterial resistance at three different hospitals.

    PubMed

    Vlahović-Palcevski, V; Morović, M; Palcevski, G; Betica-Radić, L

    2001-01-01

    It has been generally recognized that the prevalence of bacterial resistance among bacteria is an unavoidable consequence of antibiotic use and is positively linked to the overall use of antibacterial drugs. The purpose of this study was to investigate the extent of antimicrobial usage and to evaluate the antimicrobial resistance at three different hospital settings in Croatia: a clinical hospital, a general hospital and a specialized clinic for infectious diseases. In this survey the antimicrobial drug consumption and antimicrobial susceptibility test results were analyzed for the first 6 months of 1997 in three different hospitals in Croatia: the University Hospital Center (UHC), Rijeka, the Clinic for Infectious Diseases 'Dr Fran Mihaljević', Zagreb and the Dubrovnik General Hospital. The data were collected from corresponding hospital pharmacy records and microbiology laboratories. Antimicrobial drug utilization was expressed in number of defined daily doses (DDDs) per 100 bed days. High antimicrobial utilization and high resistance rates were found in all three hospitals. At the Clinic for Infectious Diseases, the most frequently used antimicrobials where those of narrow spectrum while at the UHC Rijeka and the Dubrovnik General Hospital the broad spectrum antimicrobials were mostly used. The highest antimicrobial consumption was noted at the Susak locality of the UHC, Rijeka, where the highest resistance rates of bacteria to antimicrobials were also found. Results of this observational study indicate that attempts should be made to reduce the influence of factors that may lead to emergent resistance. The most effective approach to the prevention of transmission of multidrug-resistant pathogens is preventing the initial emergence of resistance. A rational and strict antibiotic policy is thus of great importance for the optimal use of these agents.

  14. Reprogrammable microbial cell-based therapeutics against antibiotic-resistant bacteria.

    PubMed

    Hwang, In Young; Koh, Elvin; Kim, Hye Rim; Yew, Wen Shan; Chang, Matthew Wook

    2016-07-01

    The discovery of antimicrobial drugs and their subsequent use has offered an effective treatment option for bacterial infections, reducing morbidity and mortality over the past 60 years. However, the indiscriminate use of antimicrobials in the clinical, community and agricultural settings has resulted in selection for multidrug-resistant bacteria, which has led to the prediction of possible re-entrance to the pre-antibiotic era. The situation is further exacerbated by significantly reduced antimicrobial drug discovery efforts by large pharmaceutical companies, resulting in a steady decline in the number of new antimicrobial agents brought to the market in the past several decades. Consequently, there is a pressing need for new antimicrobial therapies that can be readily designed and implemented. Recently, it has become clear that the administration of broad-spectrum antibiotics can lead to collateral damage to the human commensal microbiota, which plays several key roles in host health. Advances in genetic engineering have opened the possibility of reprogramming commensal bacteria that are in symbiotic existence throughout the human body to implement antimicrobial drugs with high versatility and efficacy against pathogenic bacteria. In this review, we discuss recent advances and potentialities of engineered bacteria in providing a novel antimicrobial strategy against antibiotic resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Antimicrobial resistance in the 21st century: a multifaceted challenge.

    PubMed

    Nolte, O

    2014-04-01

    Antimicrobial resistance, the ability of (pathogenic) bacteria to withstand the action of antibiotic drugs, has recently been rated of having an impact on humans similar to that of global climate change. Indeed, during the last years medicine has faced the development of highly resistant bacterial strains, which were, as a consequence of worldwide travel activity, dispersed all over the globe. This is even more astonishing if taking into account that antibiotics were introduced into human medicine not even hundred years ago. Resistance covers different principle aspects, natural resistance, acquired resistance and clinical resistance. In the modern microbiology laboratory, antimicrobial resistance is determined by measuring the susceptibility of micro-organisms in vitro in the presence of antimicrobials. However, since the efficacy of an antibiotic depends on its pharmacokinetic and pharmacodynamics properties, breakpoints are provided to translate minimal inhibitory concentration to categorical efficacy (i.e. susceptible or resistant). Resistance in one microorganism against one particular drug may drive treatment decisions of clinicians, thereby fostering selection pressure to resistance development against another antibiotic. Thereby, bacteria may acquire more and more resistance traits, ending up with multi-resistance. To this end, antimicrobial resistance becomes a public health concern, not only in terms of limited treatment options but also due to its economic burden. The current paper provides a summary of the main topics associated with antimicrobial resistance as an introduction to this special issue.

  16. Food Production and Antimicrobial Resistance – The Next 100 Years

    USDA-ARS?s Scientific Manuscript database

    Production of food is complex and ensuring the safety of food for human consumption provides serious challenges. Since 1996 the U.S. has conducted surveillance on food borne and commensal antimicrobial resistance bacteria through the National Antimicrobial Resistance Monitoring System - Enteric Bac...

  17. [Antimicrobial resistance testing in clinical practice].

    PubMed

    Doi, Yohei

    2012-02-01

    Previously unrecognized or underrecognized antimicrobial resistant bacteria, including NDM-1-producing Enterobacteriaceae and multidrug-resistant Acinetobacter baumannii, were recently identified in health care facilities in Japan. Vigilance in the clinical microbiology laboratory for these organisms is the key to early recognition of their emergence. Many of these organisms can be confirmed or at least suspected through routine susceptibility testing, which can then be referred to reference laboratories for further phenotypic or genetic testing. Antimicrobial resistance testing plays a crucial role in patient management, infection control and monitoring of local as well as national and international epidemiology.

  18. Occurrence of antimicrobial resistance among bacterial pathogens and indicator bacteria in pigs in different European countries from year 2002 – 2004: the ARBAO-II study

    PubMed Central

    Hendriksen, Rene S; Mevius, Dik J; Schroeter, Andreas; Teale, Christopher; Jouy, Eric; Butaye, Patrick; Franco, Alessia; Utinane, Andra; Amado, Alice; Moreno, Miguel; Greko, Christina; Stärk, Katharina DC; Berghold, Christian; Myllyniemi, Anna-Liisa; Hoszowski, Andrzej; Sunde, Marianne; Aarestrup, Frank M

    2008-01-01

    Background The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003–05. The aim of this project was to establish a program for the continuous monitoring of antimicrobial susceptibility of pathogenic and indicator bacteria from food animals using validated and harmonised methodologies. In this report the first data on the occurrence of antimicrobial resistance among bacteria causing infections in pigs are reported. Methods Susceptibility data from 17,642 isolates of pathogens and indicator bacteria including Actinobacillus pleuropneumoniae, Streptococcus suis and Escherichia coli isolated from pigs were collected from fifteen European countries in 2002–2004. Results Data for A. pleuropneumoniae from infected pigs were submitted from five countries. Most of the isolates from Denmark were susceptible to all drugs tested with the exceptions of a low frequency of resistance to tetracycline and trimethoprim – sulphonamide. Data for S. suis were obtained from six countries. In general, a high level of resistance to tetracycline (48.0 – 92.0%) and erythromycin (29.1 – 75.0%) was observed in all countries whereas the level of resistance to ciprofloxacin and penicillin differed between the reporting countries. Isolates from England (and Wales), France and The Netherlands were all susceptible to penicillin. In contrast the proportion of strains resistant to ciprofloxacin ranged from 12.6 to 79.0% (2004) and to penicillin from 8.1 – 13.0% (2004) in Poland and Portugal. Data for E. coli from infected and healthy pigs were obtained from eleven countries. The data reveal a high level of resistance to tetracyclines, streptomycin and ampicillin among infected pigs whereas in healthy pigs the frequency of resistance was lower. Conclusion Bacterial resistance to some antimicrobials was frequent with different levels of resistance being observed to several antimicrobial

  19. Antimicrobial resistance monitoring projects for zoonotic and indicator bacteria of animal origin: common aspects and differences between EASSA and EFSA.

    PubMed

    Moyaert, Hilde; de Jong, Anno; Simjee, Shabbir; Thomas, Valérie

    2014-07-16

    Resistance monitoring programmes are essential to generate data for inclusion in the scientific risk assessment of the potential for transmission of antimicrobial-resistant bacteria or their resistance determinants from food-producing animals to humans. This review compares the technical specifications on monitoring of antimicrobial resistance in zoonotic Salmonella, Campylobacter and indicator Escherichia coli and Enterococcus as performed by the European Food Safety Authority (EFSA) with veterinary pharmaceutical industry's European Antimicrobial Susceptibility Surveillance in Animals (EASSA) programme. The authors conclude that most of EFSA's recent monitoring recommendations have been covered by EASSA since the start of the latter programme in 1998. The major difference between the two programmes is the classification into 'susceptible' versus 'resistant'. While EFSA categorises all isolates with an MIC value above the epidemiological cut-off value as 'resistant', EASSA differentiates between 'percentage decreased susceptible' and 'percentage clinical resistant' strains by applying both epidemiological cut-off values and clinical breakpoints. Because there is still a need to further improve harmonisation among individual EU Member State activities, Animal Health Industry welcomes EFSA's initiative to further improve the quality of resistance monitoring as it is of utmost importance to apply standardised collection procedures and harmonised susceptibility testing, when monitoring antimicrobial resistance across Europe. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Susceptibility to rifaximin and other antimicrobials of bacteria isolated in patients with acute gastrointestinal infections in Southeast Mexico.

    PubMed

    Novoa-Farias, O; Frati-Munari, A C; Peredo, M A; Flores-Juárez, S; Novoa-García, O; Galicia-Tapia, J; Romero-Carpio, C E

    Enteropathogenic bacteria isolated in Mexico City have shown a high rate of resistance to different antibiotics, with the exception of rifaximin (RIF). RIF is a nonabsorbable antibiotic that reaches high fecal concentrations (≈ 8,000μg/g). Susceptibility to antimicrobials can vary in different geographic regions. To study the susceptibility to rifaximin and other antimicrobials of enteropathogenic bacteria isolated in patients with acute diarrhea in the southeastern region of Mexico. A total of 614 strains of bacteria isolated from patients with acute diarrhea from 4 cities in Southeast Mexico were analyzed. An antibiogram with the following antibiotics was created: ampicillin (AMP), trimethoprim/sulfamethoxazole (T-S), neomycin (NEO), furazolidone (FUR), ciprofloxacin (CIP), chloramphenicol (CHL), and fosfomycin (FOS), assessed through the agar diffusion method at the standard concentrations recommended by the Clinical and Laboratory Standards Institute (CLSI) and the American Society for Microbiology (ASM), and RIF, assessed through microdilution at 4 concentrations. The bacteria were Escherichia coli (55%), as the majority, in all its pathogenic variants, Shigella (16.8%), Salmonella (15.3%), Aeromonas (7.8%), and less than 5% Campylobacter, Yersinia, Vibrio, and Plesiomonas. The accumulated overall susceptibility to RIF was 69.1, 90.8, 98.9, and 100% at concentrations of 100, 200, 400, and 800μg/ml, respectively. Overall susceptibility to other antibiotics was FOS 82.8%, CHL 76.8%, CIP 73.9%, FUR 64%, T-S 58.7%, NEO 55.8%, and AMP 23.8%. Susceptibility to RIF at 400 and 800μg was significantly greater than with the other antimicrobials (P<.001). The data of the present study were similar to those of a previous study carried out in Mexico City: susceptibility to RIF in > 98% of the bacterial strains and a high frequency of resistance to several common antimicrobials. Copyright © 2017 Asociación Mexicana de Gastroenterología. Publicado por Masson Doyma M

  1. Prevalence and antimicrobial resistance in Escherichia coli from food and animals in Lagos, Nigeria

    USDA-ARS?s Scientific Manuscript database

    Background Foodborne bacteria are often associated with human infections; these infections can become more complicated to treat if the bacteria are also resistant to antimicrobials. In this study, prevalence, antimicrobial resistance, and genetic relatedness of Escherichia coli among food producing ...

  2. Characterization of Vancomycin-Resistant Enterococcus faecalis and Enterococcus faecium Isolated from Fresh Produces and Human Fecal Samples.

    PubMed

    Kim, Min-Chan; Cha, Min-Hyeok; Ryu, Jae-Gee; Woo, Gun-Jo

    2017-04-01

    Increased enterococcal infections in hospitals and multidrug-resistant and vancomycin-resistant enterococci (VRE) isolated from humans, animals, and food sources raised public health concern on the presence of VRE in multiple sources. We performed a comparative analysis of the antimicrobial resistance and genetics of VRE isolates derived from fresh produce and human fecal samples. Of 389 Enterococcus isolates, 8 fecal and 3 produce isolates were resistant to vancomycin and teicoplanin; all harbored vanA gene. The VRE isolates showed multidrug-resistant properties. The isolates from fresh produce in this study showed to have the common shared characteristics with the isolates from humans by the results of antimicrobial resistance, multilocus sequence typing, and Tn 1546 transposon analysis. Therefore, VRE isolates from fresh produce are likely related to VRE derived from humans. The results suggested that VRE may contaminate vegetables through the environment, and the contaminated vegetables could then act as a vehicle for human infections. Ongoing nationwide surveillance of antibiotic resistance and the promotion of the proper use of antibiotics are necessary.

  3. Antimicrobial resistance patterns of bacteria isolated from canine urinary samples submitted to a New Zealand veterinary diagnostic laboratory between 2005-2012.

    PubMed

    McMeekin, C H; Hill, K E; Gibson, I R; Bridges, J P; Benschop, J

    2017-03-01

    To identify and describe culture and antimicrobial resistance (AMR) patterns in bacteria isolated from canine urinary samples submitted to a New Zealand veterinary diagnostic laboratory. Records from a veterinary diagnostic laboratory were examined for bacterial isolates cultured from canine urine samples between January 2005 and December 2012. Culture and susceptibility results were compiled with information on the age, sex and breed of dog. Repeat submissions were removed. Susceptibility was assessed using results of the Kirby-Bauer disk diffusion method, for a standard panel including amoxicillin-clavulanic acid (AMC), cefovecin (from 2010-2012), cephalothin, clindamycin, enrofloxacin and trimethoprim-sulphonamide (TMS). A total of 5,786 urine samples were submitted for analysis, and 3,135 bacterial isolates were cultured from 2,184 samples. Of these 3,135 isolates, 1,104 (35.2%) were Escherichia coli, 442 (14.1%) were Staphylococcus spp., 357 (11.4%) Proteus mirabilis and 276 (8.8%) were Enterococcus spp. The frequency of culture-positive samples increased with increasing age in both female and male dogs (p<0.001). The percentage of E. coli isolates resistant to AMC and cephalothin increased between 2005 and 2012 (p<0.001), as did resistance to enrofloxacin (p=0.022), but there was no change in resistance to TMS (p=0.696). Enrofloxacin was the antimicrobial with the least resistance shown by the four most common bacteria isolated during the course of the study. The results of this study provide important regional information regarding the prevalence of bacterial uropathogens and their susceptibility patterns. There was an increase in resistance to some commonly used antimicrobials in the treatment of urinary tract infections. Having access to regional antimicrobial susceptibility results is crucial when forming guidelines for the use of antimicrobials for the treatment of urinary tract infections. Given changes in practising habits and antimicrobial usage over

  4. Antimicrobial resistant Salmonella enterica and Escherichia coli recovered from dairy operations

    USDA-ARS?s Scientific Manuscript database

    Antimicrobial resistance has become a major public health concern and animal agriculture is often implicated as a source of resistant bacteria. The primary objective of this study was to determine prevalence of antimicrobial resistance in Salmonella and E. coli from healthy animals on dairy farms i...

  5. Efflux-mediated antimicrobial resistance.

    PubMed

    Poole, Keith

    2005-07-01

    Antibiotic resistance continues to plague antimicrobial chemotherapy of infectious disease. And while true biocide resistance is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are common and the history of antibiotic resistance should not be ignored in the development and use of biocidal agents. Efflux mechanisms of resistance, both drug specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials, with some accommodating both antibiotics and biocides. This latter raises the spectre (as yet generally unrealized) of biocide selection of multiple antibiotic-resistant organisms. Multidrug efflux mechanisms are broadly conserved in bacteria, are almost invariably chromosome-encoded and their expression in many instances results from mutations in regulatory genes. In contrast, drug-specific efflux mechanisms are generally encoded by plasmids and/or other mobile genetic elements (transposons, integrons) that carry additional resistance genes, and so their ready acquisition is compounded by their association with multidrug resistance. While there is some support for the latter efflux systems arising from efflux determinants of self-protection in antibiotic-producing Streptomyces spp. and, thus, intended as drug exporters, increasingly, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, appear not to be intended as drug exporters but as exporters with, perhaps, a variety of other roles in bacterial cells. Still, given the clinical significance of multidrug (and drug-specific) exporters, efflux must be considered in formulating strategies/approaches to treating drug-resistant infections, both in the development of new agents, for example, less impacted by efflux and in targeting efflux directly with efflux inhibitors.

  6. Mechanisms of Antimicrobial Resistance in ESKAPE Pathogens

    PubMed Central

    Santajit, Sirijan; Indrawattana, Nitaya

    2016-01-01

    The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the leading cause of nosocomial infections throughout the world. Most of them are multidrug resistant isolates, which is one of the greatest challenges in clinical practice. Multidrug resistance is amongst the top three threats to global public health and is usually caused by excessive drug usage or prescription, inappropriate use of antimicrobials, and substandard pharmaceuticals. Understanding the resistance mechanisms of these bacteria is crucial for the development of novel antimicrobial agents or other alternative tools to combat these public health challenges. Greater mechanistic understanding would also aid in the prediction of underlying or even unknown mechanisms of resistance, which could be applied to other emerging multidrug resistant pathogens. In this review, we summarize the known antimicrobial resistance mechanisms of ESKAPE pathogens. PMID:27274985

  7. Mechanisms of Antimicrobial Resistance in ESKAPE Pathogens.

    PubMed

    Santajit, Sirijan; Indrawattana, Nitaya

    2016-01-01

    The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the leading cause of nosocomial infections throughout the world. Most of them are multidrug resistant isolates, which is one of the greatest challenges in clinical practice. Multidrug resistance is amongst the top three threats to global public health and is usually caused by excessive drug usage or prescription, inappropriate use of antimicrobials, and substandard pharmaceuticals. Understanding the resistance mechanisms of these bacteria is crucial for the development of novel antimicrobial agents or other alternative tools to combat these public health challenges. Greater mechanistic understanding would also aid in the prediction of underlying or even unknown mechanisms of resistance, which could be applied to other emerging multidrug resistant pathogens. In this review, we summarize the known antimicrobial resistance mechanisms of ESKAPE pathogens.

  8. Multicenter Study of Antimicrobial Susceptibility of Anaerobic Bacteria in Korea in 2012

    PubMed Central

    Lee, Yangsoon; Park, Yeon-Joon; Kim, Mi-Na; Uh, Young; Kim, Myung Sook

    2015-01-01

    Background Periodic monitoring of regional or institutional resistance trends of clinically important anaerobic bacteria is recommended, because the resistance of anaerobic pathogens to antimicrobial drugs and inappropriate therapy are associated with poor clinical outcomes. There has been no multicenter study of clinical anaerobic isolates in Korea. We aimed to determine the antimicrobial resistance patterns of clinically important anaerobes at multiple centers in Korea. Methods A total of 268 non-duplicated clinical isolates of anaerobic bacteria were collected from four large medical centers in Korea in 2012. Antimicrobial susceptibility was tested by the agar dilution method according to the CLSI guidelines. The following antimicrobials were tested: piperacillin, piperacillin-tazobactam, cefoxitin, cefotetan, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, metronidazole, and tigecycline. Results Organisms of the Bacteroides fragilis group were highly susceptible to piperacillin-tazobactam, imipenem, and meropenem, as their resistance rates to these three antimicrobials were lower than 6%. For B. fragilis group isolates and anaerobic gram-positive cocci, the resistance rates to moxifloxacin were 12-25% and 11-13%, respectively. Among B. fragilis group organisms, the resistance rates to tigecycline were 16-17%. Two isolates of Finegoldia magna were non-susceptible to chloramphenicol (minimum inhibitory concentrations of 16-32 mg/L). Resistance patterns were different among the different hospitals. Conclusions Piperacillin-tazobactam, cefoxitin, and carbapemems are highly active β-lactam agents against most of the anaerobes. The resistance rates to moxifloxacin and tigecycline are slightly higher than those in the previous study. PMID:26206683

  9. Antimicrobial susceptibility profiles of gram-negative bacteria causing infections collected across India during 2014-2016: Study for monitoring antimicrobial resistance trend report.

    PubMed

    Veeraraghavan, Balaji; Jesudason, Mark Ranjan; Prakasah, John Antony Jude; Anandan, Shalini; Sahni, Rani Diana; Pragasam, Agila Kumari; Bakthavatchalam, Yamuna Devi; Selvakumar, Rajesh Joseph; Dhole, T N; Rodrigues, Camilla; Roy, Indranil; Joshi, Sangeetha; Chaudhuri, Bhaskar Narayan; Chitnis, D S

    2018-01-01

    The emergence of antibiotic resistance among bacterial pathogens in the hospital and community has increased the concern to the health-care providers due to the limited treatment options. Surveillance of antimicrobial resistance (AMR) in frequently isolated bacterial pathogens causing severe infections is of great importance. The data generated will be useful for the clinicians to decide empiric therapy on the local epidemiological resistance profile of the antimicrobial agents. This study aims to monitor the distribution of bacterial pathogen and their susceptibility pattern to the commonly used antimicrobial agents. This study includes Gram-negative bacilli collected from intra-abdominal, urinary tract and respiratory tract infections during 2014-2016. Isolates were collected from seven hospitals across India. All the study isolates were characterised up to species level, and minimum inhibitory concentration was determined for a wide range of antimicrobials included in the study panel. The test results were interpreted as per standard Clinical Laboratory Standards Institute guidelines. A total of 2731 isolates of gram-negative bacteria were tested during study period. The most frequently isolated pathogens were 44% of Escherichia coli (n = 1205) followed by 25% of Klebsiella pneumoniae (n = 676) and 11% of Pseudomonas aeruginosa (n = 308). Among the antimicrobials tested, carbapenems were the most active, followed by amikacin and piperacillin/tazobactam. The rate of extended-spectrum beta-lactamase (ESBL)-positive isolates were ranged from 66%-77% in E. coli to 61%-72% in K. pneumoniae, respectively. Overall, colistin retains its activity in > 90% of the isolates tested and appear promising. Increasing rates of ESBL producers have been noted, which is alarming. Further, carbapenem resistance was also gradually increasing, which needs much attention. Overall, this study data show that carbapenems, amikacin and colistin continue to be the best agents available to

  10. Genomic and functional techniques to mine the microbiome for novel antimicrobials and antimicrobial resistance genes.

    PubMed

    Adu-Oppong, Boahemaa; Gasparrini, Andrew J; Dantas, Gautam

    2017-01-01

    Microbial communities contain diverse bacteria that play important roles in every environment. Advances in sequencing and computational methodologies over the past decades have illuminated the phylogenetic and functional diversity of microbial communities from diverse habitats. Among the activities encoded in microbiomes are the abilities to synthesize and resist small molecules, yielding antimicrobial activity. These functions are of particular interest when viewed in light of the public health emergency posed by the increase in clinical antimicrobial resistance and the dwindling antimicrobial discovery and approval pipeline, and given the intimate ecological and evolutionary relationship between antimicrobial biosynthesis and resistance. Here, we review genomic and functional methods that have been developed for accessing the antimicrobial biosynthesis and resistance capacity of microbiomes and highlight outstanding examples of their applications. © 2016 New York Academy of Sciences.

  11. Tackling Threats and Future Problems of Multidrug-Resistant Bacteria.

    PubMed

    Medina, Eva; Pieper, Dietmar Helmut

    With the advent of the antibiotic era, the overuse and inappropriate consumption and application of antibiotics have driven the rapid emergence of multidrug-resistant pathogens. Antimicrobial resistance increases the morbidity, mortality, length of hospitalization and healthcare costs. Among Gram-positive bacteria, Staphylococcus aureus (MRSA) and multidrug-resistant (MDR) Mycobacterium tuberculosis, and among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBLs)-producing bacteria have become a major global healthcare problem in the 21st century. The pressure to use antibiotics guarantees that the spread and prevalence of these as well as of future emerging multidrug-resistant pathogens will be a persistent phenomenon. The unfeasibility of reversing antimicrobial resistance back towards susceptibility and the critical need to treat bacterial infection in modern medicine have burdened researchers and pharmaceutical companies to develop new antimicrobials effective against these difficult-to-treat multidrug-resistant pathogens. However, it can be anticipated that antibiotic resistance will continue to develop more rapidly than new agents to treat these infections become available and a better understanding of the molecular, evolutionary and ecological mechanisms governing the spread of antibiotic resistance is needed. The only way to curb the current crisis of antimicrobial resistance will be to develop entirely novel strategies to fight these pathogens such as combining antimicrobial drugs with other agents that counteract and obstruct the antibiotic resistant mechanisms expressed by the pathogen. Furthermore, as many antibiotics are often inappropriately prescribed, a more personalized approach based on precise diagnosis tools will ensure that proper treatments can be promptly applied leading to more targeted and effective therapies. However, in more general terms, also the overall use and release of antibiotics in the environment needs to be

  12. A new methodology to assess antimicrobial resistance of bacteria in coastal waters; pilot study in a Mediterranean hydrosystem

    NASA Astrophysics Data System (ADS)

    Almakki, Ayad; Estèves, Kevin; Vanhove, Audrey S.; Mosser, Thomas; Aujoulat, Fabien; Marchandin, Hélène; Toubiana, Mylène; Monfort, Patrick; Jumas-Bilak, Estelle; Licznar-Fajardo, Patricia

    2017-10-01

    The global resistome of coastal waters has been less studied than that of other waters, including marine ones. Here we develop an original method for characterizing the antimicrobial resistance of bacterial communities in coastal waters. The method combines the determination of a new parameter, the community Inhibitory Concentration (c-IC) of antibiotics (ATBs), and the description of the taxonomic richness of the resistant bacteria. We test the method in a Mediterranean hydrosystem, in the Montpellier region, France. Three types of waters are analyzed: near coastal river waters (Lez), lagoon brackish waters (Mauguio), and lake freshwaters (Salagou). Bacterial communities are grown in vitro in various conditions of temperature, salinity, and ATB concentrations. From these experiments, we determine the concentrations of ATB that decrease the bacterial community abundance by 50% (c-IC50) and by 90% (c-IC90). In parallel, we determine the taxonomic repertory of the resistant growing bacteria communities (repertory of Operational Taxonomic Units [OTU]). Temperature and salinity influence the abundance of the cultivable bacteria in presence of ATBs and hence the c-ICs. Very low ATB concentrations can decrease the bacterial abundance significantly. Beside a few ubiquitous genera (Bacillus, Pseudomonas, Shewanella, Vibrio), most resistant OTUs are specific of a type of water. In brackish water, resistant OTUs are more diverse and their community structure less vulnerable to ATBs than those in freshwater. We anticipate that c-IC measurement combined with taxonomic description can be applied to any littoral region to characterize the resistant bacterial communities in the coastal waters. This would help us to evaluate the vulnerability of aquatic ecosystems to antimicrobial pressure.

  13. Increased survival of experimentally evolved antimicrobial peptide-resistant Staphylococcus aureus in an animal host

    PubMed Central

    Dobson, Adam J; Purves, Joanne; Rolff, Jens

    2014-01-01

    Antimicrobial peptides (AMPs) have been proposed as new class of antimicrobial drugs, following the increasing prevalence of bacteria resistant to antibiotics. Synthetic AMPs are functional analogues of highly evolutionarily conserved immune effectors in animals and plants, produced in response to microbial infection. Therefore, the proposed therapeutic use of AMPs bears the risk of ‘arming the enemy’: bacteria that evolve resistance to AMPs may be cross-resistant to immune effectors (AMPs) in their hosts. We used a panel of populations of Staphylococcus aureus that were experimentally selected for resistance to a suite of individual AMPs and antibiotics to investigate the ‘arming the enemy’ hypothesis. We tested whether the selected strains showed higher survival in an insect model (Tenebrio molitor) and cross-resistance against other antimicrobials in vitro. A population selected for resistance to the antimicrobial peptide iseganan showed increased in vivo survival, but was not more virulent. We suggest that increased survival of AMP-resistant bacteria almost certainly poses problems to immune-compromised hosts. PMID:25469169

  14. Fecal-coliform bacteria in extended-aeration plant sludge

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Anderson, M.; Kester, G.; Arant, S.

    1998-07-01

    The concentration of fecal-coliform bacteria in sludge from extended-aeration plants was analyzed for compliance with new state and federal land application requirements. This study was initiated to determine if additional digestion would be necessary for plants to meet the new pathogen standards of less than 2 million CFU per gm of solids. Sludge was found to contain less than 2 million fecal coliform bacteria/gm of sludge as a result of a combination or aerobic digestion and/or long term storage.

  15. Chapter A7. Section 7.1. Fecal Indicator Bacteria

    USGS Publications Warehouse

    Myers, Donna N.; Sylvester, Marc A.

    1997-01-01

    Fecal indicator bacteria are used to assess the microbiological quality of water because, although not typically disease causing, they are correlated with the presence of several waterborne disease-causing organisms. The concentration of indicator bacteria is a measure of water safety for body-contact recreation or for consumption. This report provides information on the equipment, sampling protocols, and identification, enumeration, and calculation procedures that are in standard use by U.S. Geological Survey (USGS) personnel for the collection of data on fecal indicator bacteria.

  16. Identification and antimicrobial susceptibility of obligate anaerobic bacteria from clinical samples of animal origin.

    PubMed

    Mayorga, Melissa; Rodríguez-Cavallini, Evelyn; López-Ureña, Diana; Barquero-Calvo, Elías; Quesada-Gómez, Carlos

    2015-12-01

    The etiology of veterinary infectious diseases has been the focus of considerable research, yet relatively little is known about the causative agents of anaerobic infections. Susceptibility studies have documented the emergence of antimicrobial resistance and indicate distinct differences in resistance patterns related to veterinary hospitals, geographic regions, and antibiotic-prescribing regimens. The aim of the present study was to identify the obligate anaerobic bacteria from veterinary clinical samples and to determinate the in vitro susceptibility to eight antimicrobials and their resistance-associated genes. 81 clinical specimens obtained from food-producing animals, pets and wild animals were examined to determine the relative prevalence of obligate anaerobic bacteria, and the species represented. Bacteroides spp, Prevotella spp and Clostridium spp represented approximately 80% of all anaerobic isolates. Resistance to metronidazole, clindamycin, tetracycline and fluoroquinolones was found in strains isolated from food-producing animals. Ciprofloxacin, enrofloxacin and cephalotin showed the highest resistance in all isolates. In 17%, 4% and 14% of tetracycline-resistant isolates, the resistance genes tetL, tetM and tetW were respectively amplified by PCR whereas in 4% of clindamycin-resistant strains the ermG gene was detected. 26% of the isolates were positive for cepA, while only 6% harbored the cfxA (resistance-conferring genes to beta-lactams). In this study, the obligate anaerobic bacteria from Costa Rica showed a high degree of resistance to most antimicrobials tested. Nevertheless, in the majority of cases this resistance was not related to the resistance acquired genes usually described in anaerobes. It is important to address and regulate the use of antimicrobials in the agricultural industry and the empirical therapy in anaerobic bacterial infections in veterinary medicine, especially since antibiotics and resistant bacteria can persist in the

  17. Aquaculture as yet another environmental gateway to the development and globalisation of antimicrobial resistance.

    PubMed

    Cabello, Felipe C; Godfrey, Henry P; Buschmann, Alejandro H; Dölz, Humberto J

    2016-07-01

    Aquaculture uses hundreds of tonnes of antimicrobials annually to prevent and treat bacterial infection. The passage of these antimicrobials into the aquatic environment selects for resistant bacteria and resistance genes and stimulates bacterial mutation, recombination, and horizontal gene transfer. The potential bridging of aquatic and human pathogen resistomes leads to emergence of new antimicrobial-resistant bacteria and global dissemination of them and their antimicrobial resistance genes into animal and human populations. Efforts to prevent antimicrobial overuse in aquaculture must include education of all stakeholders about its detrimental effects on the health of fish, human beings, and the aquatic ecosystem (the notion of One Health), and encouragement of environmentally friendly measures of disease prevention, including vaccines, probiotics, and bacteriophages. Adoption of these measures is a crucial supplement to efforts dealing with antimicrobial resistance by developing new therapeutic agents, if headway is to be made against the increasing problem of antimicrobial resistance in human and veterinary medicine. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Age and diet effects on fecal populations and antibiotic resistance of a multi-drug resistant Escherichia coli in dairy calves

    USDA-ARS?s Scientific Manuscript database

    The use of antimicrobial drugs is reported to increase the prevalence of resistant bacteria, including commensals. Dairy calves are colonized at a very young age by a multi-drug-resistant E. coli (MDR EC), and research indicates that the prevalence is not related to recent use of antimicrobials but...

  19. Prevalence of antimicrobial-resistant Escherichia coli from raw vegetables in Lebanon.

    PubMed

    Faour-Klingbeil, Dima; Kuri, Victor; Fadlallah, Sukayna; Matar, Ghassan M

    2016-04-28

    Fresh produce has been implicated in a number of documented outbreaks of foodborne illness caused by bacteria, viruses, and parasites. Shiga toxin-producing Escherichia coli (STEC) have been detected on vegetables, raising concerns about the prevalence of E. coli contamination in produce, which can take place at various points from farm to fork. This study aimed to detect the presence of STEC and multidrug-resistant (MDR) E. coli on fresh vegetables and water from different sources along the fresh produce supply chain in Lebanon. E. coli isolates (n = 60) were group serotyped using trivalent antisera (trivalent 1 [O111+O55+O26], trivalent 2 [O86+O119+O127], trivalent 3 [O125; O126; O128], and trivalent 4 [O114+O124+O142]) and tested for stx1 and stx2 genes by polymerase chain reaction (PCR) assay. Resistance to antimicrobial agents was determined using the disk diffusion method. The virulence genes stx1 and stx2 were not detected in any of the isolates. However, 60% of the isolates were MDR and predominantly observed in trivalent 2 (32%). It is postulated that the inadequate post-harvest washing contributed to transmission of antimicrobial-resistant E. coli at wholesale and retail levels. Fresh vegetables harbor MDR E. coli and their consumption poses risks of increasing the reservoir of antimicrobial resistance in the intestines of the Lebanese population. Greater emphasis should be placed on vigilant sanitation measures at the consumption level, and effective national risk mitigation strategies are crucial to minimize fecal contamination in the early stages of production, particularly in the post-harvest washing processes.

  20. The Risk of Some Veterinary Antimicrobial Agents on Public Health Associated with Antimicrobial Resistance and their Molecular Basis

    PubMed Central

    Hao, Haihong; Sander, Pascal; Iqbal, Zahid; Wang, Yulian; Cheng, Guyue; Yuan, Zonghui

    2016-01-01

    The risk of antimicrobial agents used in food-producing animals on public health associated with antimicrobial resistance continues to be a current topic of discussion as related to animal and human public health. In the present review, resistance monitoring data, and risk assessment results of some important antimicrobial agents were cited to elucidate the possible association of antimicrobial use in food animals and antimicrobial resistance in humans. From the selected examples, it was apparent from reviewing the published scientific literature that the ban on use of some antimicrobial agents (e.g., avoparcin, fluoroquinolone, tetracyclines) did not change drug resistance patterns and did not mitigate the intended goal of minimizing antimicrobial resistance. The use of some antimicrobial agents (e.g., virginiamycin, macrolides, and cephalosporins) in food animals may have an impact on the antimicrobial resistance in humans, but it was largely depended on the pattern of drug usage in different geographical regions. The epidemiological characteristics of resistant bacteria were closely related to molecular mechanisms involved in the development, fitness, and transmission of antimicrobial resistance. PMID:27803693

  1. Prevalence and mechanisms of extended-spectrum cephalosporin resistance in clinical and fecal Enterobacteriaceae isolates from dogs in Ontario, Canada.

    PubMed

    Zhang, Pauline L C; Shen, Xiao; Chalmers, Gabhan; Reid-Smith, Richard J; Slavic, Durda; Dick, Hani; Boerlin, Patrick

    2018-01-01

    There is little information on the genetic basis of resistance to the critically important extended-spectrum cephalosporins (ESCs) in Enterobacteriaceae from dogs in Canada. This study assessed the frequency of ESC resistance in Enterobacteriaceae isolated from dogs in Ontario and the distribution of major ESC resistance genes in these bacteria. A total of 542 Enterobacteriaceae were isolated from 506 clinical samples from two diagnostic laboratories in Ontario. Eighty-eight ESC-resistant Enterobacteriaceae and 217 Escherichia coli were isolated from 234 fecal samples from dogs collected at leash-free dog parks. These fecal isolates were tested for ESC resistance along with the clinical isolates. Isolates with reduced ESC susceptibility were screened for bla CMY , bla CTX-M , and bla SHV , and all CTX-M-positive isolates underwent whole-genome sequencing. The prevalence of ESC resistance in clinical Enterobacteriaceae was 10.4%. The average frequency of fecal carriage of ESC-resistant Enterobacteriaceae in healthy dogs was 26.5%. The majority of ESC-resistant isolates were E. coli and the other major Enterobacteriaceae carrying ESC resistance genes were Klebsiella pneumoniae and Proteus mirabilis. The results show that the same ESC resistance genes can be found in clinical and fecal Enterobacteriaceae in dogs. The identified E. coli sequence types (including ST131 and ST648) and CTX-M variants (including CTX-M-14, -15, and -27) support the hypothesis of transfer of resistant bacteria between humans and dogs. CTX-M-1 was frequently found in canine fecal Enterobacteriaceae, while it is still rare in human Enterobacteriaceae in Canada, thus suggesting transfer of resistant bacteria to dogs from food animals or other sources. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Antimicrobial activity of silver nanoparticles synthesized using honey and gamma radiation against silver-resistant bacteria from wounds and burns

    NASA Astrophysics Data System (ADS)

    Hosny, A. M. S.; Kashef, M. T.; Rasmy, S. A.; Aboul-Magd, D. S.; El-Bazza, Z. E.

    2017-12-01

    Silver nanoparticles (AgNPs) are promising antimicrobial agents for treatment of wounds and burns. We synthesized AgNPs using honey at different pH values or with different gamma irradiation doses. The resulting nanoparticles were characterized by UV-vis spectroscopy, TEM, DLS and FTIR. Their antimicrobial activity, against standard bacterial strains and silver-resistant clinical isolates from infected wounds and burns, was evaluated in vitro through determination of their minimum inhibitory concentration (MIC). AgNPs prepared using 30 g of honey exposed to 5 kGy gamma radiation had the best physical characters regarding stability and uniformity of particle size and shape. They recorded the lowest MIC values against both the standard and silver-resistant isolates. In conclusion, honey and gamma radiation can be used in synthesis of highly stable pure AgNPs, without affecting the physico-chemical and antimicrobial activity of honey. This offered an advantage in terms of inhibition of silver-resistant bacteria isolates.

  3. Antimicrobial Resistance and Virulence: a Successful or Deleterious Association in the Bacterial World?

    PubMed Central

    Beceiro, Alejandro; Tomás, María

    2013-01-01

    SUMMARY Hosts and bacteria have coevolved over millions of years, during which pathogenic bacteria have modified their virulence mechanisms to adapt to host defense systems. Although the spread of pathogens has been hindered by the discovery and widespread use of antimicrobial agents, antimicrobial resistance has increased globally. The emergence of resistant bacteria has accelerated in recent years, mainly as a result of increased selective pressure. However, although antimicrobial resistance and bacterial virulence have developed on different timescales, they share some common characteristics. This review considers how bacterial virulence and fitness are affected by antibiotic resistance and also how the relationship between virulence and resistance is affected by different genetic mechanisms (e.g., coselection and compensatory mutations) and by the most prevalent global responses. The interplay between these factors and the associated biological costs depend on four main factors: the bacterial species involved, virulence and resistance mechanisms, the ecological niche, and the host. The development of new strategies involving new antimicrobials or nonantimicrobial compounds and of novel diagnostic methods that focus on high-risk clones and rapid tests to detect virulence markers may help to resolve the increasing problem of the association between virulence and resistance, which is becoming more beneficial for pathogenic bacteria. PMID:23554414

  4. Antimicrobial Resistance in Bacterial Poultry Pathogens: A Review

    PubMed Central

    Nhung, Nguyen Thi; Chansiripornchai, Niwat; Carrique-Mas, Juan J.

    2017-01-01

    Antimicrobial resistance (AMR) is a global health threat, and antimicrobial usage and AMR in animal production is one of its contributing sources. Poultry is one of the most widespread types of meat consumed worldwide. Poultry flocks are often raised under intensive conditions using large amounts of antimicrobials to prevent and to treat disease, as well as for growth promotion. Antimicrobial resistant poultry pathogens may result in treatment failure, leading to economic losses, but also be a source of resistant bacteria/genes (including zoonotic bacteria) that may represent a risk to human health. Here we reviewed data on AMR in 12 poultry pathogens, including avian pathogenic Escherichia coli (APEC), Salmonella Pullorum/Gallinarum, Pasteurella multocida, Avibacterium paragallinarum, Gallibacterium anatis, Ornitobacterium rhinotracheale (ORT), Bordetella avium, Clostridium perfringens, Mycoplasma spp., Erysipelothrix rhusiopathiae, and Riemerella anatipestifer. A number of studies have demonstrated increases in resistance over time for S. Pullorum/Gallinarum, M. gallisepticum, and G. anatis. Among Enterobacteriaceae, APEC isolates displayed considerably higher levels of AMR compared with S. Pullorum/Gallinarum, with prevalence of resistance over >80% for ampicillin, amoxicillin, tetracycline across studies. Among the Gram-negative, non-Enterobacteriaceae pathogens, ORT had the highest levels of phenotypic resistance with median levels of AMR against co-trimoxazole, enrofloxacin, gentamicin, amoxicillin, and ceftiofur all exceeding 50%. In contrast, levels of resistance among P. multocida isolates were less than 20% for all antimicrobials. The study highlights considerable disparities in methodologies, as well as in criteria for phenotypic antimicrobial susceptibility testing and result interpretation. It is necessary to increase efforts to harmonize testing practices, and to promote free access to data on AMR in order to improve treatment guidelines as well as to

  5. Microbiota and anthropic interference on antimicrobial resistance profile of bacteria isolated from Brazilian Maned-wolf (Chrysocyon brachyurus).

    PubMed

    Vieira-da-Motta, Olney; Eckhardt-de-Pontes, Luiz Antonio; Petrucci, Melissa Paes; dos Santos, Israel Pereira; da Cunha, Isabel Candia Nunes; Morato, Ronaldo Gonçalves

    2013-12-01

    Both the study of Brazilian wild mammal fauna and the conditions that foster the preservation of endangered species, such as Brazilian Maned-wolf (Chrysocyon brachyurus), in wild life are of extreme importance. In order to study the resistance profile of microbiota bacterial colonizing Brazilian Maned-wolf, this work investigated samples from eight male captive and free roaming animals originating from different Brazilian geographical regions. Samples for microbiological purposes were collected with swabs and kept in appropriate transport medium. Using routine microbiological techniques, the isolated bacteria were tested toward antimicrobial drugs by the agar disk diffusion method. Results showed that all samples from wild animals were sensitive toward all drugs tested. Conversely, the resistance profile of bacteria isolated from captive animals varied among strains and animal body site location. Escherichia coli samples from prepuce, anus and ear showed multi-resistance toward at least four drugs, especially against erythromycin and tetracycline, followed by Proteus mirabilis and P. vulgaris strains isolated from anus and ear. Among Gram-positive bacteria, strains of coagulase-negative staphylococci showed multi-resistance mainly toward erythromycin and amoxicillin. The work discusses these findings and suggests that profile of multi-resistance bacteria from captive subjects may be attributed to direct contact with human or through lifestyle factors such as feeding, predation or contact of animals with urban animals such as birds, rodents, and insects from surrounding environments.

  6. Microbiota and anthropic interference on antimicrobial resistance profile of bacteria isolated from Brazilian maned-wolf (Chrysocyon brachyurus)

    PubMed Central

    Vieira-da-Motta, Olney; Eckhardt-de-Pontes, Luiz Antonio; Petrucci, Melissa Paes; dos Santos, Israel Pereira; da Cunha, Isabel Candia Nunes; Morato, Ronaldo Gonçalves

    2013-01-01

    Both the study of Brazilian wild mammal fauna and the conditions that foster the preservation of endangered species, such as Brazilian Maned-wolf (Chrysocyon brachyurus), in wild life are of extreme importance. In order to study the resistance profile of microbiota bacterial colonizing Brazilian Maned-wolf, this work investigated samples from eight male captive and free roaming animals originating from different Brazilian geographical regions. Samples for microbiological purposes were collected with swabs and kept in appropriate transport medium. Using routine microbiological techniques, the isolated bacteria were tested toward antimicrobial drugs by the agar disk diffusion method. Results showed that all samples from wild animals were sensitive toward all drugs tested. Conversely, the resistance profile of bacteria isolated from captive animals varied among strains and animal body site location. Escherichia coli samples from prepuce, anus and ear showed multi-resistance toward at least four drugs, especially against erythromycin and tetracycline, followed by Proteus mirabilis and P. vulgaris strains isolated from anus and ear. Among Gram-positive bacteria, strains of coagulase-negative staphylococci showed multi-resistance mainly toward erythromycin and amoxicillin. The work discusses these findings and suggests that profile of multi-resistance bacteria from captive subjects may be attributed to direct contact with human or through lifestyle factors such as feeding, predation or contact of animals with urban animals such as birds, rodents, and insects from surrounding environments. PMID:24688529

  7. Regulation of antimicrobial resistance by extracytoplasmic function (ECF) sigma factors

    PubMed Central

    Woods, Emily C.; McBride, Shonna M.

    2017-01-01

    Extracytoplasmic function (ECF) sigma factors are a subfamily of σ70 sigma factors that activate genes involved in stress-response functions. In many bacteria, ECF sigma factors regulate resistance to antimicrobial compounds. This review will summarize the ECF sigma factors that regulate antimicrobial resistance in model organisms and clinically relevant pathogens. PMID:28153747

  8. Chlortetracycline - resistant intestinal bacteria in organically-raised and feral swine

    USDA-ARS?s Scientific Manuscript database

    Organically-raised swine had high fecal populations of chlortetracycline (CTC)-resistant (growing at 64 micro g CTC/ml) Escherichia coli, Megasphaera elsdenii and anaerobe populations. By comparison, predominant CTC-resistant bacteria in feral swine feces were over 1000-fold fewer and exhibited lo...

  9. Quantitative Real-Time PCR Analysis of Total Propidium Monazide -Resistant Fecal Indicator Bacteria in Wastewater

    EPA Science Inventory

    A real-time quantitative PCR (qPCR) method and a modification of this method incorporating pretreatment of samples with propidium monoazide (PMA) were evaluated for respective analyses of total and presumptively viable Enterococcus and Bacteroidales fecal indicator bacteria. Thes...

  10. Inappropriate use of antibiotics in hospitals: the complex relationship between antibiotic use and antimicrobial resistance.

    PubMed

    Cantón, Rafael; Horcajada, Juan Pablo; Oliver, Antonio; Garbajosa, Patricia Ruiz; Vila, Jordi

    2013-09-01

    Hospitals are considered an excellent compartment for the selection of resistant and multi-drug resistant (MDR) bacteria. The overuse and misuse of antimicrobial agents are considered key points fuelling this situation. Antimicrobial stewardship programs have been designed for better use of these compounds to prevent the emergence of resistant microorganisms and to diminish the upward trend in resistance. Nevertheless, the relationship between antibiotic use and antimicrobial resistance is complex, and the desired objectives are difficult to reach. Various factors affecting this relationship have been advocated including, among others, antibiotic exposure and mutant selection windows, antimicrobial pharmacodynamics, the nature of the resistance (natural or acquired, including mutational and that associated with horizontal gene transfer) and the definition of resistance. Moreover, antimicrobial policies to promote better use of these drugs should be implemented not only in the hospital setting coupled with infection control programs, but also in the community, which should also include animal and environmental compartments. Within hospitals, the restriction of antimicrobials, cycling and mixing strategies and the use of combination therapies have been used to avoid resistance. Nevertheless, the results have not always been favorable and resistant bacteria have persisted despite the theoretical benefits of these strategies. Mathematical models as well as microbiological knowledge can explain this failure, which is mainly related to the current scenario involving MDR bacteria and overcoming the fitness associated with resistance. New antimicrobials, rapid diagnostic and antimicrobial susceptibility testing and biomarkers will be useful for future antimicrobial stewardship interventions. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  11. Extended spectrum β-lactamases, carbapenemases and mobile genetic elements responsible for antibiotics resistance in Gram-negative bacteria.

    PubMed

    El Salabi, Allaaeddin; Walsh, Timothey R; Chouchani, Chedly

    2013-05-01

    Infectious diseases due to Gram-negative bacteria are a leading cause of morbidity and mortality worldwide. Antimicrobial agents represent one major therapeutic tools implicated to treat these infections. The misuse of antimicrobial agents has resulted in the emergence of resistant strains of Gram-negatives in particular Enterobacteriaceae and non-fermenters; they have an effect not only on a human but on the public health when bacteria use the resistance mechanisms to spread in the hospital environment and to the community outside the hospitals by means of mobile genetic elements. Gram-negative bacteria have become increasingly resistant to antimicrobial agents. They have developed several mechanisms by which they can withstand to antimicrobials, these mechanisms include the production of Extended-spectrum β-lactamases (ESBLs) and carbapenemases, furthermore, Gram-negative bacteria are now capable of spreading such resistance between members of the family Enterobacteriaceae and non-fermenters using mobile genetic elements as vehicles for such resistance mechanisms rendering antibiotics useless. Therefore, addressing the issue of mechanisms of antimicrobial resistance is considered one of most urgent priorities. This review will help to illustrate different resistance mechanisms; ESBLs, carbapenemases encoded by genes carried by mobile genetic elements, which are used by Gram-negative bacteria to escape antimicrobial effect.

  12. Prevalence, resistance patterns, and risk factors for antimicrobial resistance in bacteria from retail chicken meat in Colombia.

    PubMed

    Donado-Godoy, Pilar; Byrne, Barbara A; León, Maribel; Castellanos, Ricardo; Vanegas, Consuelo; Coral, Adriana; Arevalo, Alejandra; Clavijo, Viviana; Vargas, Mercedes; Romero Zuñiga, Juan J; Tafur, McAllister; Pérez-Gutierrez, Enrique; Smith, Woutrina A

    2015-04-01

    As a step toward implementing the Colombian Integrated Program for Antimicrobial Resistance Surveillance (COIPARS), this study aimed to establish the baseline antimicrobial resistance patterns of Salmonella serovars, Escherichia coli, and Enterococcus spp. isolates in retail poultry meat from independent stores and from a main chain distributor center. MICs of the isolates were determined for antimicrobials used both in humans and animals, using an automated system. Salmonella serovars were isolated from 26% of the meat samples and E. coli from 83%, whereas Enterococcus faecalis and Enterococcus faecium were detected in 81 and 13% of the meat samples, respectively. A principal finding of concern in this study was that almost 98% of isolates tested were multidrug resistant. Ceftiofur, enrofloxacin, nalidixic acid, and tetracycline were the antimicrobials that showed the highest frequency of resistance among Salmonella and E. coli isolates. For enterococci, 61.5% of E. faecium isolates were found to be resistant to quinupristin-dalfopristin; this is significant because it is used to treat nosocomial infections when vancomycin resistance is present. Vancomycin resistance was detected in 4% of the E. faecalis isolates. The results of our study highlight the need for rapid implementation of an integrated program for surveillance of antimicrobial resistance by the Colombian authorities in order to monitor trends, raise awareness, and help promote practices to safeguard later generation antimicrobial agents.

  13. ANTIMICROBIAL RESISTANCE IN SALMONELLA ISOLATES RECOVERED FROM EGGS

    USDA-ARS?s Scientific Manuscript database

    Background: Antimicrobial resistance is of global concern and first emerged in bacteria shortly after the introduction of penicillin. It is common to see resistance develop after new compounds (regardless of class) are released. However many factors influence the persistence and transmission of r...

  14. Antibiotic resistance patterns in fecal bacteria isolated from Christmas shearwater (Puffinus nativitatis) and masked booby (Sula dactylatra) at remote Easter Island.

    PubMed

    Ardiles-Villegas, Karen; González-Acuña, Daniel; Waldenström, Jonas; Olsen, Björn; Hernández, Jorge

    2011-09-01

    Antibiotic use and its implications have been discussed extensively in the past decades. This situation has global consequences when antibiotic resistance becomes widespread in the intestinal bacterial flora of stationary and migratory birds. This study investigated the incidence of fecal bacteria and general antibiotic resistance, with special focus on extended spectrum beta-lactamase (ESBL) isolates, in two species of seabirds at remote Easter Island. We identified 11 species of bacteria from masked booby (Sula dactylatra) and Christmas shearwater (Puffinus nativitatis); five species of gram-negative bacilli, four species of Streptococcus (Enterococcus), and 2 species of Staphylococcus. In addition, 6 types of bacteria were determined barely to the genus level. General antibiotic susceptibility was measured in the 30 isolated Enterobacteriaceae to 11 antibiotics used in human and veterinary medicine. The 10 isolates that showed a phenotypic ESBL profile were verified by clavulanic acid inhibition in double mixture discs with cefpodoxime, and two ESBL strains were found, one strain in masked booby and one strain in Christmas shearwater. The two bacteria harboring the ESBL type were identified as Serratia odorifera biotype 1, which has zoonotic importance. Despite minimal human presence in the masked booby and Christmas shearwater habitats, and the extreme geographic isolation of Easter Island, we found several multiresistant bacteria and even two isolates with ESBL phenotypes. The finding of ESBLs has animal and public health significance and is of potential concern, especially because the investigation was limited in size and indicated that antibiotic-resistant bacteria now are distributed globally.

  15. Serotypes, Virulence Factors, and Antimicrobial Susceptibilities of Vaginal and Fecal Isolates of Escherichia coli from Giant Pandas

    PubMed Central

    Wang, Xin; Xia, Xiaodong; Li, Desheng; Wang, Chengdong; Chen, Shijie; Hou, Rong

    2013-01-01

    Although Escherichia coli typically colonizes the intestinal tract and vagina of giant pandas, it has caused enteric and systemic disease in giant pandas and greatly impacts the health and survival of this endangered species. In order to understand the distribution and characteristics of E. coli from giant pandas, 67 fecal and 30 vaginal E. coli isolates from 21 giant pandas were characterized for O serogroups, phylogenetic groups, antimicrobial susceptibilities, and pulsed-field gel electrophoresis (PFGE) profiles. In addition, these isolates were tested for the presence of extraintestinal pathogenic E. coli (ExPEC) and diarrheagenic E. coli (DEC) by multiplex PCR detection of specific virulence genes. The most prevalent serogroups for all E. coli isolates were O88, O18, O167, O4, and O158. ExPEC isolates were detected mostly in vaginal samples, and DEC isolates were detected only in fecal samples. Phylogenetic group B1 predominated in fecal isolates, while groups B2 and D were frequently detected in vaginal isolates. Resistance to trimethoprim-sulfamethoxazole was most frequently observed, followed by resistance to nalidixic acid and tetracycline. All except five isolates were typeable by using XbaI and were categorized into 74 PFGE patterns. Our findings indicate that panda E. coli isolates exhibited antimicrobial resistance, and potentially pathogenic E. coli isolates were present in giant pandas. In addition, these E. coli isolates were genetically diverse. This study may provide helpful information for developing strategies in the future to control E. coli infections of giant pandas. PMID:23793635

  16. Serotypes, virulence factors, and antimicrobial susceptibilities of vaginal and fecal isolates of Escherichia coli from giant pandas.

    PubMed

    Wang, Xin; Yan, Qigui; Xia, Xiaodong; Zhang, Yanming; Li, Desheng; Wang, Chengdong; Chen, Shijie; Hou, Rong

    2013-09-01

    Although Escherichia coli typically colonizes the intestinal tract and vagina of giant pandas, it has caused enteric and systemic disease in giant pandas and greatly impacts the health and survival of this endangered species. In order to understand the distribution and characteristics of E. coli from giant pandas, 67 fecal and 30 vaginal E. coli isolates from 21 giant pandas were characterized for O serogroups, phylogenetic groups, antimicrobial susceptibilities, and pulsed-field gel electrophoresis (PFGE) profiles. In addition, these isolates were tested for the presence of extraintestinal pathogenic E. coli (ExPEC) and diarrheagenic E. coli (DEC) by multiplex PCR detection of specific virulence genes. The most prevalent serogroups for all E. coli isolates were O88, O18, O167, O4, and O158. ExPEC isolates were detected mostly in vaginal samples, and DEC isolates were detected only in fecal samples. Phylogenetic group B1 predominated in fecal isolates, while groups B2 and D were frequently detected in vaginal isolates. Resistance to trimethoprim-sulfamethoxazole was most frequently observed, followed by resistance to nalidixic acid and tetracycline. All except five isolates were typeable by using XbaI and were categorized into 74 PFGE patterns. Our findings indicate that panda E. coli isolates exhibited antimicrobial resistance, and potentially pathogenic E. coli isolates were present in giant pandas. In addition, these E. coli isolates were genetically diverse. This study may provide helpful information for developing strategies in the future to control E. coli infections of giant pandas.

  17. Antimicrobial use in swine production and its effect on the swine gut microbiota and antimicrobial resistance.

    PubMed

    Holman, Devin B; Chénier, Martin R

    2015-11-01

    Antimicrobials have been used in swine production at subtherapeutic levels since the early 1950s to increase feed efficiency and promote growth. In North America, a number of antimicrobials are available for use in swine. However, the continuous administration of subtherapeutic, low concentrations of antimicrobials to pigs also provides selective pressure for antimicrobial-resistant bacteria and resistance determinants. For this reason, subtherapeutic antimicrobial use in livestock remains a source of controversy and concern. The swine gut microbiota demonstrates a number of changes in response to antimicrobial administration depending on the dosage, duration of treatment, age of the pigs, and gut location that is sampled. Both culture-independent and -dependent studies have also shown that the swine gut microbiota contains a large number of antimicrobial resistance determinants even in the absence of antimicrobial exposure. Heavy metals, such as zinc and copper, which are often added at relatively high doses to swine feed, may also play a role in maintaining antimicrobial resistance and in the stability of the swine gut microbiota. This review focuses on the use of antimicrobials in swine production, with an emphasis on the North American regulatory context, and their effect on the swine gut microbiota and on antimicrobial resistance determinants in the gut microbiota.

  18. Antimicrobial resistance: harmonisation of national antimicrobial resistance monitoring and surveillance programmes in animals and in animal-derived food.

    PubMed

    Franklin, A; Acar, J; Anthony, F; Gupta, R; Nicholls, T; Tamura, Y; Thompson, S; Threlfall, E J; Vose, D; van Vuuren, M; White, D G; Wegener, H C; Costarrica, M L

    2001-12-01

    A guideline on the harmonisation of national antimicrobial resistance monitoring and surveillance programmes in animals and animal-derived foods has been developed by the Ad hoc Group of experts on antimicrobial resistance of the Office International des Epizooties. The objective of the guideline is to allow the generation of comparable data from various national surveillance and monitoring systems in order to compare the situations in different regions or countries and to consolidate results at the national, regional and international level. Definitions of surveillance and monitoring are provided. National systems should be able to detect the emergence of resistance, and to determine the prevalence of resistant bacteria. The resulting data should be used in the assessment of risks to public health and should contribute to the establishment of a risk management policy. Specific factors identified for harmonisation include the animal species, food commodities, sampling plans, bacterial species, antimicrobials to be tested, laboratory methods, data reporting, database structure and the structure of reports.

  19. Antimicrobial resistance of mastitis pathogens.

    PubMed

    Oliver, Stephen P; Murinda, Shelton E

    2012-07-01

    Antibiotics are used extensively in the dairy industry to combat disease and to improve animal performance. Antibiotics such as penicillin, cephalosporin, streptomycin, and tetracycline are used for the treatment and prevention of diseases affecting dairy cows caused by a variety of gram-positive and gram-negative bacteria. Antibiotics are often administrated routinely to entire herds to prevent mastitis during the dry period. An increase in the incidence of disease in a herd generally results in increased use of antimicrobials, which in turn increases the potential for antibiotic residues in milk and the potential for increased bacterial resistance to antimicrobials. Continued use of antibiotics in the treatment and prevention of diseases of dairy cows will continue to be scrutinized. It is clear that strategies employing the prudent use of antimicrobials are needed. This clearly illustrates the importance of effective herd disease prevention and control programs. Based on studies published to date, scientific evidence does not support widespread, emerging resistance among mastitis pathogens to antibacterial drugs even though many of these antibiotics have been used in the dairy industry for treatment and prevention of disease for several decades. However, it is clear that use of antibiotics in dairy cows can contribute to increased antimicrobial resistance. While antimicrobial resistance does occur, we are of the opinion that the advantages of using antibiotics for the treatment of mastitis far outweigh the disadvantages. The clinical consequences of antimicrobial resistance of dairy pathogens affecting humans appear small. Antimicrobial resistance among dairy pathogens, particularly those found in milk, is likely not a human health concern as long as the milk is pasteurized. However, there are an increasing number of people who choose to consume raw milk. Transmission of an antimicrobial-resistant mastitis pathogen and/or foodborne pathogen to humans could occur

  20. Search Engine for Antimicrobial Resistance: A Cloud Compatible Pipeline and Web Interface for Rapidly Detecting Antimicrobial Resistance Genes Directly from Sequence Data.

    PubMed

    Rowe, Will; Baker, Kate S; Verner-Jeffreys, David; Baker-Austin, Craig; Ryan, Jim J; Maskell, Duncan; Pearce, Gareth

    2015-01-01

    Antimicrobial resistance remains a growing and significant concern in human and veterinary medicine. Current laboratory methods for the detection and surveillance of antimicrobial resistant bacteria are limited in their effectiveness and scope. With the rapidly developing field of whole genome sequencing beginning to be utilised in clinical practice, the ability to interrogate sequencing data quickly and easily for the presence of antimicrobial resistance genes will become increasingly important and useful for informing clinical decisions. Additionally, use of such tools will provide insight into the dynamics of antimicrobial resistance genes in metagenomic samples such as those used in environmental monitoring. Here we present the Search Engine for Antimicrobial Resistance (SEAR), a pipeline and web interface for detection of horizontally acquired antimicrobial resistance genes in raw sequencing data. The pipeline provides gene information, abundance estimation and the reconstructed sequence of antimicrobial resistance genes; it also provides web links to additional information on each gene. The pipeline utilises clustering and read mapping to annotate full-length genes relative to a user-defined database. It also uses local alignment of annotated genes to a range of online databases to provide additional information. We demonstrate SEAR's application in the detection and abundance estimation of antimicrobial resistance genes in two novel environmental metagenomes, 32 human faecal microbiome datasets and 126 clinical isolates of Shigella sonnei. We have developed a pipeline that contributes to the improved capacity for antimicrobial resistance detection afforded by next generation sequencing technologies, allowing for rapid detection of antimicrobial resistance genes directly from sequencing data. SEAR uses raw sequencing data via an intuitive interface so can be run rapidly without requiring advanced bioinformatic skills or resources. Finally, we show that SEAR

  1. Potential impact of antimicrobial resistance in wildlife, environment and human health

    PubMed Central

    Radhouani, Hajer; Silva, Nuno; Poeta, Patrícia; Torres, Carmen; Correia, Susana; Igrejas, Gilberto

    2014-01-01

    Given the significant spatial and temporal heterogeneity in antimicrobial resistance distribution and the factors that affect its evolution, dissemination, and persistence, it is important to highlight that antimicrobial resistance must be viewed as an ecological problem. Monitoring the resistance prevalence of indicator bacteria such as Escherichia coli and enterococci in wild animals makes it possible to show that wildlife has the potential to serve as an environmental reservoir and melting pot of bacterial resistance. These researchers address the issue of antimicrobial-resistant microorganism proliferation in the environment and the related potential human health and environmental impact. PMID:24550896

  2. Efflux pumps as antimicrobial resistance mechanisms.

    PubMed

    Poole, Keith

    2007-01-01

    Antibiotic resistance continues to hamper antimicrobial chemotherapy of infectious disease, and while biocide resistance outside of the laboratory is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are not uncommon. Efflux mechanisms, both drug-specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials in important human pathogens. Multidrug efflux mechanisms are generally chromosome-encoded, with their expression typically resultant from mutations in regulatory genes, while drug-specific efflux mechanisms are encoded by mobile genetic elements whose acquisition is sufficient for resistance. While it has been suggested that drug-specific efflux systems originated from efflux determinants of self-protection in antibiotic-producing Actinomycetes, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, are appreciated as having an intended housekeeping function unrelated to drug export and resistance. Thus, it will be important to elucidate the intended natural function of these efflux mechanisms in order, for example, to anticipate environmental conditions or circumstances that might promote their expression and, so, compromise antimicrobial chemotherapy. Given the clinical significance of antimicrobial exporters, it is clear that efflux must be considered in formulating strategies for treatment of drug-resistant infections, both in the development of new agents, for example, less impacted by efflux or in targeting efflux directly with efflux inhibitors.

  3. Antimicrobial Resistance in Non-Typhoidal Salmonella from Humans, Retail Meats and Food Animals: 2002-2007

    USDA-ARS?s Scientific Manuscript database

    Background. The National Antimicrobial Resistance Monitor System (NARMS) tracks antimicrobial susceptibility in enteric bacteria from humans, retail meats and food animals. We analyzed changes in ceftiofur resistance (TioR), nalidixic acid resistance (NalR) and multidrug resistance (MDR-AmpC, define...

  4. Antibiotic resistance of lactic acid bacteria isolated from dry-fermented sausages.

    PubMed

    Fraqueza, Maria João

    2015-11-06

    Dry-fermented sausages are meat products highly valued by many consumers. Manufacturing process involves fermentation driven by natural microbiota or intentionally added starter cultures and further drying. The most relevant fermentative microbiota is lactic acid bacteria (LAB) such as Lactobacillus, Pediococcus and Enterococcus, producing mainly lactate and contributing to product preservation. The great diversity of LAB in dry-fermented sausages is linked to manufacturing practices. Indigenous starters development is considered to be a very promising field, because it allows for high sanitary and sensorial quality of sausage production. LAB have a long history of safe use in fermented food, however, since they are present in human gastrointestinal tract, and are also intentionally added to the diet, concerns have been raised about the antimicrobial resistance in these beneficial bacteria. In fact, the food chain has been recognized as one of the key routes of antimicrobial resistance transmission from animal to human bacterial populations. The World Health Organization 2014 report on global surveillance of antimicrobial resistance reveals that this issue is no longer a future prediction, since evidences establish a link between the antimicrobial drugs use in food-producing animals and the emergence of resistance among common pathogens. This poses a risk to the treatment of nosocomial and community-acquired infections. This review describes the possible sources and transmission routes of antibiotic resistant LAB of dry-fermented sausages, presenting LAB antibiotic resistance profile and related genetic determinants. Whenever LAB are used as starters in dry-fermented sausages processing, safety concerns regarding antimicrobial resistance should be addressed since antibiotic resistant genes could be mobilized and transferred to other bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Scoping review to identify potential non-antimicrobial interventions to mitigate antimicrobial resistance in commensal enteric bacteria in North American cattle production systems.

    PubMed

    Murphy, C P; Fajt, V R; Scott, H M; Foster, M J; Wickwire, P; McEwen, S A

    2016-01-01

    A scoping review was conducted to identify modifiable non-antimicrobial factors to reduce the occurrence of antimicrobial resistance in cattle populations. Searches were developed to retrieve peer-reviewed published studies in animal, human and in vitro microbial populations. Citations were retained when modifiable non-antimicrobial factors or interventions potentially associated with antimicrobial resistance were described. Studies described resistance in five bacterial genera, species or types, and 40 antimicrobials. Modifiable non-antimicrobial factors or interventions ranged widely in type, and the depth of evidence in animal populations was shallow. Specific associations between a factor or intervention with antimicrobial resistance in a population (e.g. associations between organic systems and tetracycline susceptibility in E. coli from cattle) were reported in a maximum of three studies. The identified non-antimicrobial factors or interventions were classified into 16 themes. Most reported associations between the non-antimicrobial modifiable factors or interventions and antimicrobial resistance were not statistically significant (P > 0·05 and a confidence interval including 1), but when significant, the results were not consistent in direction (increase or decrease in antimicrobial resistance) or magnitude. Research is needed to better understand the impacts of promising modifiable factors or interventions on the occurrence of antimicrobial resistance before any recommendations can be offered or adopted.

  6. Plasmid-Mediated Antimicrobial Resistance in Staphylococci and Other Firmicutes.

    PubMed

    Schwarz, Stefan; Shen, Jianzhong; Wendlandt, Sarah; Fessler, Andrea T; Wang, Yang; Kadlec, Kristina; Wu, Cong-Ming

    2014-12-01

    In staphylococci and other Firmicutes, resistance to numerous classes of antimicrobial agents, which are commonly used in human and veterinary medicine, is mediated by genes that are associated with mobile genetic elements. The gene products of some of these antimicrobial resistance genes confer resistance to only specific members of a certain class of antimicrobial agents, whereas others confer resistance to the entire class or even to members of different classes of antimicrobial agents. The resistance mechanisms specified by the resistance genes fall into any of three major categories: active efflux, enzymatic inactivation, and modification/replacement/protection of the target sites of the antimicrobial agents. Among the mobile genetic elements that carry such resistance genes, plasmids play an important role as carriers of primarily plasmid-borne resistance genes, but also as vectors for nonconjugative and conjugative transposons that harbor resistance genes. Plasmids can be exchanged by horizontal gene transfer between members of the same species but also between bacteria belonging to different species and genera. Plasmids are highly flexible elements, and various mechanisms exist by which plasmids can recombine, form cointegrates, or become integrated in part or in toto into the chromosomal DNA or into other plasmids. As such, plasmids play a key role in the dissemination of antimicrobial resistance genes within the gene pool to which staphylococci and other Firmicutes have access. This chapter is intended to provide an overview of the current knowledge of plasmid-mediated antimicrobial resistance in staphylococci and other Firmicutes.

  7. Motuporamine Derivatives as Antimicrobial Agents and Antibiotic Enhancers against Resistant Gram-Negative Bacteria.

    PubMed

    Borselli, Diane; Blanchet, Marine; Bolla, Jean-Michel; Muth, Aaron; Skruber, Kristen; Phanstiel, Otto; Brunel, Jean Michel

    2017-02-01

    Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump. This suggests that depowering the efflux pump provides another strategy to address antibiotic resistance. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  8. Susceptibility of bacteria isolated from acute gastrointestinal infections to rifaximin and other antimicrobial agents in Mexico.

    PubMed

    Novoa-Farías, O; Frati-Munari, A C; Peredo, M A; Flores-Juárez, S; Novoa-García, O; Galicia-Tapia, J; Romero-Carpio, C E

    2016-01-01

    Bacterial resistance may hamper the antimicrobial management of acute gastroenteritis. Bacterial susceptibility to rifaximin, an antibiotic that achieves high fecal concentrations (up to 8,000μg/g), has not been evaluated in Mexico. To determine the susceptibility to rifaximin and other antimicrobial agents of enteropathogenic bacteria isolated from patients with acute gastroenteritis in Mexico. Bacterial strains were analyzed in stool samples from 1,000 patients with diagnosis of acute gastroenteritis. The susceptibility to rifaximin (RIF) was tested by microdilution (<100, <200, <400 and <800μg/ml) and susceptibility to chloramphenicol (CHL), trimethoprim-sulfamethoxazole (T-S), neomycin (NEO), furazolidone (FUR), fosfomycin (FOS), ampicillin (AMP) and ciprofloxacin (CIP) was tested by agar diffusion at the concentrations recommended by the Clinical & Laboratory Standards Institute and the American Society for Microbiology. Isolated bacteria were: enteropathogenic Escherichia coli (E. coli) (EPEC) 531, Shigella 120, non-Typhi Salmonella 117, Aeromonas spp. 80, enterotoxigenic E. coli (ETEC) 54, Yersinia enterocolitica 20, Campylobacter jejuni 20, Vibrio spp. 20, Plesiomonas shigelloides 20, and enterohemorrhagic E. coli (EHEC 0:157) 18. The overall cumulative susceptibility to RIF at <100, <200, <400, and <800μg/ml was 70.6, 90.8, 99.3, and 100%, respectively. The overall susceptibility to each antibiotic was: AMP 32.2%, T-S 53.6%, NEO 54.1%, FUR 64.7%, CIP 67.3%, CLO 73%, and FOS 81.3%. The susceptibility to RIF <400 and RIF <800μg/ml was significantly greater than with the other antibiotics (p<0.001). Resistance of enteropathogenic bacteria to various antibiotics used in gastrointestinal infections is high. Rifaximin was active against 99-100% of these enteropathogens at reachable concentrations in the intestine with the recommended dose. Copyright © 2015 Asociación Mexicana de Gastroenterología. Published by Masson Doyma México S.A. All rights reserved.

  9. Seasonal variation of fecal indicator bacteria in storm events within the US stormwater database.

    PubMed

    Pan, Xubin; Jones, Kim D

    2012-01-01

    Bacteria are one of the major causes of surface water impairments in the USA. Over the past several years, best management practices, including detention basins, manufactured devices, grass swales, filters and bioretention cells have been used to remove bacteria and other pollutants from stormwater runoff. However, there are data gaps in the comprehensive studies of bacteria concentrations in stormwater runoff. In this paper, the event mean concentration (EMC) of fecal indicator bacteria (Enterococcus, Escherichia coli, fecal Streptococcus group bacteria, and fecal coliform) across the USA was retrieved from the international stormwater best management practices database to analyze the seasonal variations of inflow and outflow event mean concentrations and removal efficiencies. The Kruskal-Wallis test was employed to determine the seasonal variations of bacteria indicator concentrations and removals, and the two-sample Kolmogorov-Smirnov test was used for comparing different seasonal outcomes. The results indicate that all the inflow EMC of FIB in stormwater runoff is above the water quality criteria. The seasonal differences of fecal Streptococcus group bacteria and fecal coliform are significant. Summer has the potential to increase the bacteria EMC and illustrate the seasonal differences.

  10. Use of antimicrobials in veterinary medicine and mechanisms of resistance.

    PubMed

    Schwarz, S; Chaslus-Dancla, E

    2001-01-01

    This review deals with the application of antimicrobial agents in veterinary medicine and food animal production and the possible consequences arising from the widespread and multipurpose use of antimicrobials. The various mechanisms that bacteria have developed to escape the inhibitory effects of the antimicrobials most frequently used in the veterinary field are reported in detail. Resistance of bacteria to tetracyclines, macrolide-lincosamide-streptogramin antibiotics, beta-lactam antibiotics, aminoglycosides, sulfonamides, trimethoprim, fluoroquinolones and chloramphenicol/florfenicol is described with regard to enzymatic inactivation, decreased intracellular drug accumulation and modification/protection/replacement of the target sites. In addition, basic information is given about mobile genetic elements which carry the respective resistance genes, such as plasmids, transposons, and gene cassettes/integrons, and their ways of spreading via conjugation, mobilisation, transduction, and transformation.

  11. Antimicrobial Resistance in Salmonella Isolates Recovered from Slaughter Cattle

    USDA-ARS?s Scientific Manuscript database

    *Background*: Antimicrobial resistance is of global concern and first emerged in bacteria shortly after the introduction of penicillin. It is common to see resistance develop after new compounds (regardless of class) are released. However many factors influence the persistence and transmission of r...

  12. Antimicrobial effects of lysophosphatidylcholine on methicillin-resistant Staphylococcus aureus.

    PubMed

    Miyazaki, Haruko; Midorikawa, Naoko; Fujimoto, Saki; Miyoshi, Natsumi; Yoshida, Hideto; Matsumoto, Tetsuya

    2017-07-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important health care-associated and community-associated pathogen and causes a large number of infections worldwide. For the purpose of application to topical treatment of MRSA infection, we examined the antimicrobial effects of lysophosphatidylcholine (LPC) on MRSA strains. We also investigated the combination effect of LPC and gentamicin on MRSA growth. The LPC minimum inhibitory concentrations (MIC) for Gram-positive ( S. aureus, Staphylococcus epidermidis , and Streptococcus pneumoniae ) and Gram-negative ( Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae , and Pseudomonas aeruginosa ) bacteria were measured by the broth microdilution method. The mechanism of LPC-mediated MRSA killing was investigated by membrane permeability analysis with DiSC3(5) fluorescence and growth curve analysis. Lastly, the effects of LPC on gentamicin-induced bactericidal activity were determined in combination treatment studies with 15 gentamicin-resistant MRSA isolates from the skin, nose, or ears. The LPC MIC for Gram-positive bacteria varied between 32 µg/ml and >2048 µg/ml, whereas that for all Gram-negative bacteria was >2048 µg/ml. Consistently, membrane permeability analysis showed that LPC was substantially more effective in inducing membrane permeability in Gram-positive bacteria than in Gram-negative counterparts. Growth curve analysis in cotreatment studies demonstrated that LPC has intrinsic bactericidal effects and can also potentiate gentamicin sensitivity in resistant MRSA strains. Our study demonstrates that LPC exhibits intrinsic antimicrobial effects and can enhance the antimicrobial effects of gentamicin for resistant MRSA strains, suggesting that LPC may be a beneficial additive in topical antibiotics for superficial skin infections.

  13. Occurrence of tetracycline-resistant fecal coliforms and their resistance genes in an urban river impacted by municipal wastewater treatment plant discharges.

    PubMed

    Zhang, Chong-Miao; Du, Cong; Xu, Huan; Miao, Yan-Hui; Cheng, Yan-Yan; Tang, Hao; Zhou, Jin-Hong; Wang, Xiao-Chang

    2015-01-01

    Antibiotic resistance of fecal coliforms in an urban river poses great threats to both human health and the environment. To investigate the occurrence and distribution of antibiotic resistant bacteria in an urban river, water samples were collected from the Chanhe River in Xi'an, China. After membrane filtration of water samples, the tetracycline resistance rate of fecal coliforms and their resistance genes were detected by plating and polymerase chain reaction (PCR), respectively. We found that fecal coliforms were generally resistant to tetracycline and saw average resistance rates of 44.7%. The genes tetA and tetB were widely detected, and their positive rate was 60%-100% and 40%-90%, respectively. We found few strains containing tetC, tetK, tetQ and tetX, and we did not identify any strains containing tetG, tetM or tetO. The prevalence of tetA and tetB over other genes indicated that the main mechanism for resistance to tetracycline is by changes to the efflux pump. Our analysis of the types and proportion of tetracycline resistance genes in the Chanhe River at locations upstream and downstream of the urban center suggests that the increased number of tetracycline-resistant fecal coliforms and spatial variation of tetracycline resistance genes diversity were related to municipal wastewater treatment plant discharge.

  14. Competitive effect of commensal faecal bacteria from growing swine fed chlortetracycline-supplemented feed on beta-haemolytic Escherichia coli strains with multiple antimicrobial resistance plasmids

    USDA-ARS?s Scientific Manuscript database

    Multidrug-resistant (MDR) bacteria are an increasing threat to human and animal health. The objectives of the present study were to determine: (1) the effect of Aureomycin® on MDR E. coli field strains in growing swine fecal fluid; (2) the competitive fitness of each of these strains in long-term c...

  15. The Role of Flies in the Maintenance of Antimicrobial Resistance in Farm Environments.

    PubMed

    Fukuda, Akira; Usui, Masaru; Okamura, Masashi; Dong-Liang, Hu; Tamura, Yutaka

    2018-04-30

    Flies play an important role as vectors in the transmission of antimicrobial-resistant bacteria (ARB) and are hypothesized to transfer ARB between internal and external livestock housing areas. The aim of this study was to understand the role that flies may play in the maintenance of ARB in the farm environment. We first evaluated the fate of ingested antimicrobial-resistant Escherichia coli harboring a plasmid containing antimicrobial-resistance genes (ARGs) throughout the housefly (Musca domestica) life cycle, from adult to the subsequent F1 generation. Antimicrobial-resistant E. coli was isolated from different life cycle stages and ARG carriage quantified. The ingested E. coli persisted throughout the fly life cycle, and ARG carriage was maintained at a constant level in the housefly microbiota. To clarify the transmission of ARB from flies to livestock, 30-day-old chickens were inoculated with maggots containing antimicrobial-resistant E. coli. Based on the quantification of bacteria isolated from cecal samples, antimicrobial-resistant E. coli persisted in these chickens for at least 16 days. These results suggest that flies act as a reservoir of ARB throughout their life cycle and may therefore be involved in the maintenance and circulation of ARB in the farm environment.

  16. Antimicrobial resistance among Salmonella enterica serovar Infantis from broiler carcasses in Serbia

    NASA Astrophysics Data System (ADS)

    Nikolić, A.; Baltić, T.; Velebit, B.; Babić, M.; Milojević, L.; Đorđević, V.

    2017-09-01

    This study aimed to investigate antimicrobial resistance of Salmonella Infantis isolates from poultry carcasses in Serbia. A total of 48 Salmonella isolates were examined for antimicrobial resistance. A panel of 10 antibiotics was selected for testing. Isolates showed resistance to sulfamethoxazole, ceftazidime and cefotaxime (100%). However, the highest number of Salmonella Infantis isolates were sensitive to chloramphenicol. The usage of antibiotics in food producing animals could result in antimicrobial resistance pathogenic bacteria especially Salmonella spp. in poultry, which may be transmitted to humans through the food chain and increase risk of treatment failures.

  17. Multidrug-Resistance and Toxic Metal Tolerance of Medically Important Bacteria Isolated from an Aquaculture System

    PubMed Central

    Resende, Juliana Alves; Silva, Vânia L.; Fontes, Cláudia Oliveira; Souza-Filho, Job Alves; de Oliveira, Tamara Lopes Rocha; Coelho, Cíntia Marques; César, Dionéia Evangelista; Diniz, Cláudio Galuppo

    2012-01-01

    The use of antimicrobials and toxic metals should be considered carefully in aquaculture and surrounding environments. We aimed to evaluate medically relevant bacteria in an aquaculture system and their susceptibility to antimicrobials and toxic metals. Selective cultures for enterobacteria (ENT), non-fermenting Gram-negative rods (NFR) and Gram-positive cocci (GPC) were obtained from water samples collected in two different year seasons. The isolated bacteria were biochemically identified and antimicrobial and toxic metal susceptibility patterns were determined. Overall, 407 representative strains were recovered. In general, bacteria isolated from fish ponds showed higher multiple antibiotic resistance indices when compared to those isolated from a water-fed canal. Resistance to penicillin and azithromycin was observed more frequently in the GPC group, whereas resistance to ampicillin and ampicillin/sulbactam or gentamicin was observed more frequently in the ENT and NFR groups, respectively. All the isolated bacteria were tolerant to nickel, zinc, chromium and copper at high levels (≥1,024 μg mL−1), whereas tolerance to cadmium and mercury varied among the isolated bacteria (2–1,024 μg mL−1). Multidrug-resistant bacteria were more frequent and diverse in fish ponds than in the water-fed canal. A positive correlation was observed between antimicrobial resistance and metal tolerance. The data point out the need for water treatment associated with the aquaculture system. PMID:22972388

  18. Age and diet effects on fecal populations of a multi-drug-resistant Escherichia coli in dairy calves

    USDA-ARS?s Scientific Manuscript database

    The use of antimicrobial drugs is reported to increase the prevalence of resistant bacteria, including commensals. Dairy calves are colonized at a very young age by a multi-drug-resistant E. coli (MDR EC), and research indicates that the prevalence is not related to recent use of antimicrobials but...

  19. A brief multi-disciplinary review on antimicrobial resistance in medicine and its linkage to the global environmental microbiota

    PubMed Central

    Cantas, L.; Shah, Syed Q. A.; Cavaco, L. M.; Manaia, C. M.; Walsh, F.; Popowska, M.; Garelick, H.; Bürgmann, H.; Sørum, H.

    2013-01-01

    The discovery and introduction of antimicrobial agents to clinical medicine was one of the greatest medical triumphs of the 20th century that revolutionized the treatment of bacterial infections. However, the gradual emergence of populations of antimicrobial-resistant pathogenic bacteria resulting from use, misuse, and abuse of antimicrobials has today become a major global health concern. Antimicrobial resistance (AMR) genes have been suggested to originate from environmental bacteria, as clinically relevant resistance genes have been detected on the chromosome of environmental bacteria. As only a few new antimicrobials have been developed in the last decade, the further evolution of resistance poses a serious threat to public health. Urgent measures are required not only to minimize the use of antimicrobials for prophylactic and therapeutic purposes but also to look for alternative strategies for the control of bacterial infections. This review examines the global picture of antimicrobial resistance, factors that favor its spread, strategies, and limitations for its control and the need for continuous training of all stake-holders i.e., medical, veterinary, public health, and other relevant professionals as well as human consumers, in the appropriate use of antimicrobial drugs. PMID:23675371

  20. Synthesis and Evaluation of Antimicrobial and Antibiofilm Properties of A-Type Procyanidin Analogues against Resistant Bacteria in Food.

    PubMed

    Alejo-Armijo, Alfonso; Glibota, Nicolás; Frías, María P; Altarejos, Joaquín; Gálvez, Antonio; Salido, Sofía; Ortega-Morente, Elena

    2018-03-07

    Natural A-type procyanidins have shown very interesting biological activities, such as their proven antiadherence properties against pathogenic bacteria. In order to find the structural features responsible for their activities, we describe herein the design and synthesis of six A-type procyanidin analogues and the evaluation of their antimicrobial and antibiofilm properties against 12 resistant bacteria, both Gram positive and Gram negative, isolated from organic foods. The natural A-type procyanidin A-2, which had known antiadherence activity, was also tested as a reference compound for the comparative studies. Within the series, analogue 4, which had a NO 2 group on ring A, showed the highest antimicrobial activity (MIC of 10 μg/mL) and was one of the best molecules at preventing biofilm formation (up to 40% decreases at 100 μg/mL) and disrupting preformed biofilms (up to 40% reductions at 0.1 μg/mL). Structure-activity relationships are also analyzed.

  1. Insights on antimicrobial resistance, biofilms and the use of phytochemicals as new antimicrobial agents.

    PubMed

    Borges, Anabela; Saavedra, Maria J; Simões, Manuel

    2015-01-01

    Antimicrobial resistance is one of the most serious public health problems. This is of particular concern when bacteria become resistant to various antimicrobial agents simultaneously and when they form biofilms. Consequently, therapeutic options for the treatment of infections have become limited, leading frequently to recurrent infections, treatment failure and increase of morbidity and mortality. Both, persistence and spread of antibiotic resistance, in combination with decreased effectiveness and increased toxicity of current antibiotics have emphasized the urgent need to search alternative sources of antimicrobial substances. Plants are recognized as a source of unexplored chemical structures with high therapeutic potential, including antimicrobial activity against clinically important microorganisms. Additionally, phytochemicals (plant secondary metabolites) present several advantages over synthetic molecules, including green status and different mechanisms of action from antibiotics which could help to overcome the resistance problem. In this study, an overview of the main classes of phytochemicals with antimicrobial properties and their mode of action is presented. A revision about the application of phytochemicals for biofilm prevention and control is also done. Moreover, the use of phytochemicals as scaffolds of new functional molecules to expand the antibiotics pipeline is reviewed.

  2. The diversity of antimicrobial resistance genes among staphylococci of animal origin.

    PubMed

    Wendlandt, Sarah; Feßler, Andrea T; Monecke, Stefan; Ehricht, Ralf; Schwarz, Stefan; Kadlec, Kristina

    2013-08-01

    Staphylococci of animal origin harbor a wide variety of resistance genes. So far, more than 40 different resistance genes have been identified in staphylococci from animals. This includes genes that confer resistance to virtually all classes of antimicrobial agents approved for use in animals, such as penicillins, cephalosporins, tetracyclines, macrolides, lincosamides, phenicols, aminoglycosides, aminocyclitols, pleuromutilins, and diaminopyrimidines. The gene products of some of these resistance genes confer resistance to only specific members of a class of antimicrobial agents, whereas others confer resistance to the entire class or even to members of different classes of antimicrobial agents. The resistance mechanisms specified by the resistance genes fall into three major categories: (i) enzymatic inactivation, (ii) active efflux, or (iii) protection/modification/replacement of the cellular target sites of the antimicrobial agents. Mobile genetic elements, in particular plasmids and transposons, play a major role as carriers of antimicrobial resistance genes in animal staphylococci. They facilitate the exchange of resistance genes with staphylococci of human origin but also with other Gram-positive bacteria. Copyright © 2013 Elsevier GmbH. All rights reserved.

  3. Antibiotic-resistant bacteria: a challenge for the food industry.

    PubMed

    Capita, Rosa; Alonso-Calleja, Carlos

    2013-01-01

    Antibiotic-resistant bacteria were first described in the 1940s, but whereas new antibiotics were being discovered at a steady rate, the consequences of this phenomenon were slow to be appreciated. At present, the paucity of new antimicrobials coming into the market has led to the problem of antibiotic resistance fast escalating into a global health crisis. Although the selective pressure exerted by the use of antibiotics (particularly overuse or misuse) has been deemed the major factor in the emergence of bacterial resistance to these antimicrobials, concerns about the role of the food industry have been growing in recent years and have been raised at both national and international levels. The selective pressure exerted by the use of antibiotics (primary production) and biocides (e.g., disinfectants, food and feed preservatives, or decontaminants) is the main driving force behind the selection and spread of antimicrobial resistance throughout the food chain. Genetically modified (GM) crops with antibiotic resistance marker genes, microorganisms added intentionally to the food chain (probiotic or technological) with potentially transferable antimicrobial resistance genes, and food processing technologies used at sub-lethal doses (e.g., alternative non-thermal treatments) are also issues for concern. This paper presents the main trends in antibiotic resistance and antibiotic development in recent decades, as well as their economic and health consequences, current knowledge concerning the generation, dissemination, and mechanisms of antibacterial resistance, progress to date on the possible routes for emergence of resistance throughout the food chain and the role of foods as a vehicle for antibiotic-resistant bacteria. The main approaches to prevention and control of the development, selection, and spread of antibacterial resistance in the food industry are also addressed.

  4. [Fluoroquinolones and Gram-negative bacteria: antimicrobial activity and mechanisms of resistance].

    PubMed

    Luzzaro, F

    2008-04-01

    Fluoroquinolones acts by interacting with type II topoisomerases (DNA gyrase and topoisomerases IV). Related to this mechanism of action, bacteria have developed resistance mechanisms consisting in some target mutations (GyrA/GyrB for DNA gyrase and ParC/ParE for topoisomerase IV) or in a reduced access to the target itself, by either decreased permeability or augmented expression of efflux pumps, such as AcrAB and MexAB. Along with these classical mechanisms of chromosomal resistance, the presence of fluoroquinolones resistant proteins (Qnr) has been recently evidenced, codified by transmissible genes by means of plasmids, especially in Enterobacter spp., Escherichia coli and Klebsiella pneumoniae, whereas Proteus mirabilis and non fermenter Gram-negative, like Acinetobacter spp. and Pseudomonas aeruginosa, are not involved in such a kind of resistance. Qnr proteins determine a slight increase in MIC values, which often remains below the susceptibility breakpoint. More relevant is their impact on MPC values. Additionally, new specific resistance mechanisms have been described. AAC(6')-Ib-cr represents the first enzyme able to inactivate, by acetylation, antimicrobials of two different classes, aminoglycosides and fluoroquinolones. However, ciprofloxacin and norfloxacin, but not levofloxacin, are susceptible to this enzyme action. Finally, the presence of another resistance mechanism has been reported, an efflux-pump plasmid-mediated, codified by the QepA gene, which acts by a selective mechanism. Only hydrophilic fluoroquinolones, i.e. norfloxacin and ciprofloxacin, but not all the other ones, i.e. levofloxacin, moxifloxacin, etc, are affected by this mechanism. In the light of these new information, it is clear that, in terms of bacterial resistance, it is not any more possible to assimilate one fluoroquinolones to another, since different molecules can be diversely active, due to the specific resistance mechanism.

  5. Effects of chlortetracycline and copper supplementation on the prevalence, distribution, and quantity of antimicrobial resistance genes in the fecal metagenome of weaned pigs.

    PubMed

    Agga, Getahun E; Scott, H Morgan; Vinasco, Javier; Nagaraja, T G; Amachawadi, Raghavendra G; Bai, Jianfa; Norby, Bo; Renter, David G; Dritz, Steve S; Nelssen, Jim L; Tokach, Mike D

    2015-05-01

    Use of in-feed antibiotics such as chlortetracycline (CTC) in food animals is fiercely debated as a cause of antimicrobial resistance in human pathogens; as a result, alternatives to antibiotics such as heavy metals have been proposed. We used a total community DNA approach to experimentally investigate the effects of CTC and copper supplementation on the presence and quantity of antimicrobial resistance elements in the gut microbial ecology of pigs. Total community DNA was extracted from 569 fecal samples collected weekly over a 6-week period from groups of 5 pigs housed in 32 pens that were randomized to receive either control, CTC, copper, or copper plus CTC regimens. Qualitative and quantitative PCR were used to detect the presence of 14 tetracycline resistance (tet) genes and to quantify gene copies of tetA, tetB, blaCMY-2 (a 3rd generation cephalosporin resistance gene), and pcoD (a copper resistance gene), respectively. The detection of tetA and tetB decreased over the subsequent sampling periods, whereas the prevalence of tetC and tetP increased. CTC and copper plus CTC supplementation increased both the prevalence and gene copy numbers of tetA, while decreasing both the prevalence and gene copies of tetB. In summary, tet gene presence was initially very diverse in the gut bacterial community of weaned pigs; thereafter, copper and CTC supplementation differentially impacted the prevalence and quantity of the various tetracycline, ceftiofur and copper resistance genes resulting in a less diverse gene population. Published by Elsevier B.V.

  6. Single molecule resolution of the antimicrobial action of quantum dot-labeled sushi peptide on live bacteria.

    PubMed

    Leptihn, Sebastian; Har, Jia Yi; Chen, Jianzhu; Ho, Bow; Wohland, Thorsten; Ding, Jeak Ling

    2009-05-11

    Antimicrobial peptides are found in all kingdoms of life. During the evolution of multicellular organisms, antimicrobial peptides were established as key elements of innate immunity. Most antimicrobial peptides are thought to work by disrupting the integrity of cell membranes, causing pathogen death. As antimicrobial peptides target the membrane structure, pathogens can only acquire resistance by a fundamental change in membrane composition. Hence, the evolution of pathogen resistance has been a slow process. Therefore antimicrobial peptides are valuable alternatives to classical antibiotics against which multiple drug-resistant bacteria have emerged. For potential therapeutic applications as antibiotics a thorough knowledge of their mechanism of action is essential. Despite the increasingly comprehensive understanding of the biochemical properties of these peptides, the actual mechanism by which antimicrobial peptides lyse microbes is controversial. Here we investigate how Sushi 1, an antimicrobial peptide derived from the horseshoe crab (Carcinoscorpius rotundicauda), induces lysis of Gram-negative bacteria. To follow the entire process of antimicrobial action, we performed a variety of experiments including transmission electron microscopy and fluorescence correlation spectroscopy as well as single molecule tracking of quantum dot-labeled antimicrobial peptides on live bacteria. Since in vitro measurements do not necessarily correlate with the in vivo action of a peptide we developed a novel fluorescent live bacteria lysis assay. Using fully functional nanoparticle-labeled Sushi 1, we observed the process of antimicrobial action at the single-molecule level. Recently the hypothesis that many antimicrobial peptides act on internal targets to kill the bacterium has been discussed. Here, we demonstrate that the target sites of Sushi 1 are outer and inner membranes and are not cytosolic. Further, our findings suggest four successive steps of the bactericidal process

  7. Antimicrobial use and antimicrobial resistance in food animals.

    PubMed

    Xiong, Wenguang; Sun, Yongxue; Zeng, Zhenling

    2018-05-25

    Antimicrobials have been widely used in food animals for growth promotion since the 1950s. Antimicrobial resistance emerges in animal production settings and frequently spreads to humans through the food chain and direct contact. There have been international efforts to restrict or ban antimicrobials used for both humans and animals. Denmark has taken positive strides in the development of a comprehensive database DANMAP to track antimicrobial usage and resistance. Although food animals are sources of antimicrobial resistance, there is little evidence that antimicrobial resistance originates from food animals. This review comprehensively introduces the history and trends of antimicrobial use, the emergence and spread of antimicrobial resistance in food animals provides suggestions to tackle the problems of the spread of antimicrobial resistance.

  8. Antibiotic resistance genes and residual antimicrobials in cattle feedlot surface soil

    USDA-ARS?s Scientific Manuscript database

    Antibiotic residues and resistant bacteria in cattle feedlot manure may impact antibiotic resistance in the environment. This study investigated common antimicrobials (tetracyclines and monensin) and associated resistance genes in cattle feedlot soils over time. Animal diets and other feedlot soil...

  9. Effect of Tetracycline Dose and Treatment Mode on Selection of Resistant Coliform Bacteria in Nursery Pigs

    PubMed Central

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders; Herrero-Fresno, Ana; Larsen, Inge; Holm, Anders; Nielsen, Jens Peter; Christiansen, Lasse Engbo; Angen, Øystein; Ahmed, Shahana

    2017-01-01

    ABSTRACT This study describes the results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on the selection of antibiotic-resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4 to 7 weeks of age) in five pig herds were treated with oxytetracycline for Lawsonia intracellularis-induced diarrhea. Each group was randomly allocated to one of five treatment groups: oral flock treatment with a (i) high (20 mg/kg of body weight), (ii) medium (10 mg/kg), or (iii) low (5 mg/kg) dose, (iv) oral pen-wise (small-group) treatment (10 mg/kg), and (v) individual intramuscular injection treatment (10 mg/kg). All groups were treated once a day for 5 days. In all groups, treatment caused a rise in the numbers and proportions of tetracycline-resistant coliform bacteria right after treatment, followed by a significant drop by the time that the pigs left the nursery unit. The counts and proportions of tetracycline-resistant coliforms did not vary significantly between treatment groups, except immediately after treatment, when the highest treatment dose resulted in the highest number of resistant coliforms. A control group treated with tiamulin did not show significant changes in the numbers or proportions of tetracycline-resistant coliforms. Selection for tetracycline-resistant coliforms was significantly correlated to selection for ampicillin- and sulfonamide-resistant strains but not to selection for cefotaxime-resistant strains. In conclusion, the difference in the dose of oxytetracycline and the way in which the drug was applied did not cause significantly different levels of selection of tetracycline-resistant coliform bacteria under the conditions tested. IMPORTANCE Antimicrobial resistance is a global threat to human health. Treatment of livestock with antimicrobials has a direct impact on this problem, and there is a need to improve the ways that we use antimicrobials in

  10. Effect of Tetracycline Dose and Treatment Mode on Selection of Resistant Coliform Bacteria in Nursery Pigs.

    PubMed

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders; Herrero-Fresno, Ana; Larsen, Inge; Holm, Anders; Nielsen, Jens Peter; Christiansen, Lasse Engbo; Angen, Øystein; Ahmed, Shahana; Folkesson, Anders; Olsen, John Elmerdahl

    2017-06-15

    This study describes the results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on the selection of antibiotic-resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4 to 7 weeks of age) in five pig herds were treated with oxytetracycline for Lawsonia intracellularis -induced diarrhea. Each group was randomly allocated to one of five treatment groups: oral flock treatment with a (i) high (20 mg/kg of body weight), (ii) medium (10 mg/kg), or (iii) low (5 mg/kg) dose, (iv) oral pen-wise (small-group) treatment (10 mg/kg), and (v) individual intramuscular injection treatment (10 mg/kg). All groups were treated once a day for 5 days. In all groups, treatment caused a rise in the numbers and proportions of tetracycline-resistant coliform bacteria right after treatment, followed by a significant drop by the time that the pigs left the nursery unit. The counts and proportions of tetracycline-resistant coliforms did not vary significantly between treatment groups, except immediately after treatment, when the highest treatment dose resulted in the highest number of resistant coliforms. A control group treated with tiamulin did not show significant changes in the numbers or proportions of tetracycline-resistant coliforms. Selection for tetracycline-resistant coliforms was significantly correlated to selection for ampicillin- and sulfonamide-resistant strains but not to selection for cefotaxime-resistant strains. In conclusion, the difference in the dose of oxytetracycline and the way in which the drug was applied did not cause significantly different levels of selection of tetracycline-resistant coliform bacteria under the conditions tested. IMPORTANCE Antimicrobial resistance is a global threat to human health. Treatment of livestock with antimicrobials has a direct impact on this problem, and there is a need to improve the ways that we use antimicrobials in livestock

  11. Strategic measures for the control of surging antimicrobial resistance in Hong Kong and mainland of China.

    PubMed

    Cheng, Vincent C C; Wong, Sally C Y; Ho, Pak-Leung; Yuen, Kwok-Yung

    2015-02-01

    Antimicrobial-resistant bacteria are either highly prevalent or increasing rapidly in Hong Kong and China. Treatment options for these bacteria are generally limited, less effective and more expensive. The emergence and dynamics of antimicrobial resistance genes in bacteria circulating between animals, the environment and humans are not entirely known. Nonetheless, selective pressure by antibiotics on the microbiomes of animal and human, and their associated environments (especially farms and healthcare institutions), sewage systems and soil are likely to confer survival advantages upon bacteria with antimicrobial-resistance genes, which may be further disseminated through plasmids or transposons with integrons. Therefore, antibiotic use must be tightly regulated to eliminate such selective pressure, including the illegalization of antibiotics as growth promoters in animal feed and regulation of antibiotic use in veterinary practice and human medicine. Heightened awareness of infection control measures to reduce the risk of acquiring resistant bacteria is essential, especially during antimicrobial use or institutionalization in healthcare facilities. The transmission cycle must be interrupted by proper hand hygiene, environmental cleaning, avoidance of undercooked or raw food and compliance with infection control measures by healthcare workers, visitors and patients, especially during treatment with antibiotics. In addition to these routine measures, proactive microbiological screening of hospitalized patients with risk factors for carrying resistant bacteria, including history of travel to endemic countries, transfer from other hospitals, and prolonged hospitalization; directly observed hand hygiene before oral intake of drugs, food and drinks; and targeted disinfection of high-touch or mutual-touch items, such as bed rails and bed curtains, are important. Transparency of surveillance data from each institute for public scrutiny provides an incentive for

  12. Antimicrobial copper alloys decreased bacteria on stethoscope surfaces.

    PubMed

    Schmidt, Michael G; Tuuri, Rachel E; Dharsee, Arif; Attaway, Hubert H; Fairey, Sarah E; Borg, Keith T; Salgado, Cassandra D; Hirsch, Bruce E

    2017-06-01

    Stethoscopes may serve as vehicles for transmission of bacteria among patients. The aim of this study was to assess the efficacy of antimicrobial copper surfaces to reduce the bacterial concentration associated with stethoscope surfaces. A structured prospective trial involving 21 health care providers was conducted at a pediatric emergency division (ED) (n = 14) and an adult medical intensive care unit located in tertiary care facilities (n = 7). Four surfaces common to a stethoscope and a facsimile instrument fabricated from U.S. Environmental Protection Agency-registered antimicrobial copper alloys (AMCus) were assessed for total aerobic colony counts (ACCs), methicillin-resistant Staphylococcus aureus, gram-negative bacteria, and vancomycin-resistant enterococci for 90 days. The mean ACCs collectively recovered from all stethoscope surfaces fabricated from the AMCus were found to carry significantly lower concentrations of bacteria (pediatric ED, 11.7 vs 127.1 colony forming units [CFU]/cm 2 , P < .00001) than their control equivalents. This observation was independent of health care provider or infection control practices. Absence of recovery of bacteria from the AMCu surfaces (66.3%) was significantly higher (P < .00001) than the control surfaces (22.4%). The urethane rim common to the stethoscopes was the most heavily burdened surface; mean concentrations exceeded the health care-associated infection acquisition concentration (5 CFU/cm 2 ) by at least 25×, supporting that the stethoscope warrants consideration in plans mitigating microbial cross-transmission during patient care. Stethoscope surfaces fabricated with AMCus were consistently found to harbor fewer bacteria. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  13. [Antimicrobial therapy in severe infections with multidrug-resistant Gram-negative bacterias].

    PubMed

    Duszyńska, Wiesława

    2010-01-01

    Multidrug-resistant Gram-negative bacteria pose a serious and rapidly emerging threat to patients in healthcare settings, and are especially prevalent and problematic in intensive therapy units. Recently, the emergence of pandrug-resistance in Gram-negative bacteria poses additional concerns. This review examines the clinical impact and epidemiology of multidrug-resistant Gram-negative bacteria as a cause of increased morbidity and mortality among ITU patients. Beta-lactamases, cephalosporinases and carbapenemases play the most important role in resistance to antibiotics. Despite the tendency to increased resistance, carbapenems administered by continuous infusion remain the most effective drugs in severe sepsis. Drug concentration monitoring, albeit rarely used in practice, is necessary to ensure an effective therapeutic effect.

  14. Antimicrobial effects of lysophosphatidylcholine on methicillin-resistant Staphylococcus aureus

    PubMed Central

    Miyazaki, Haruko; Midorikawa, Naoko; Fujimoto, Saki; Miyoshi, Natsumi; Yoshida, Hideto; Matsumoto, Tetsuya

    2017-01-01

    Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is an important health care-associated and community-associated pathogen and causes a large number of infections worldwide. For the purpose of application to topical treatment of MRSA infection, we examined the antimicrobial effects of lysophosphatidylcholine (LPC) on MRSA strains. We also investigated the combination effect of LPC and gentamicin on MRSA growth. Methods: The LPC minimum inhibitory concentrations (MIC) for Gram-positive (S. aureus, Staphylococcus epidermidis, and Streptococcus pneumoniae) and Gram-negative (Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, and Pseudomonas aeruginosa) bacteria were measured by the broth microdilution method. The mechanism of LPC-mediated MRSA killing was investigated by membrane permeability analysis with DiSC3(5) fluorescence and growth curve analysis. Lastly, the effects of LPC on gentamicin-induced bactericidal activity were determined in combination treatment studies with 15 gentamicin-resistant MRSA isolates from the skin, nose, or ears. Results: The LPC MIC for Gram-positive bacteria varied between 32 µg/ml and >2048 µg/ml, whereas that for all Gram-negative bacteria was >2048 µg/ml. Consistently, membrane permeability analysis showed that LPC was substantially more effective in inducing membrane permeability in Gram-positive bacteria than in Gram-negative counterparts. Growth curve analysis in cotreatment studies demonstrated that LPC has intrinsic bactericidal effects and can also potentiate gentamicin sensitivity in resistant MRSA strains. Conclusions: Our study demonstrates that LPC exhibits intrinsic antimicrobial effects and can enhance the antimicrobial effects of gentamicin for resistant MRSA strains, suggesting that LPC may be a beneficial additive in topical antibiotics for superficial skin infections. PMID:28748087

  15. Antimicrobial activity of Manuka honey against antibiotic-resistant strains of the cell wall-free bacteria Ureaplasma parvum and Ureaplasma urealyticum.

    PubMed

    Hillitt, K L; Jenkins, R E; Spiller, O B; Beeton, M L

    2017-03-01

    The susceptibility of the cell wall-free bacterial pathogens Ureaplasma spp. to Manuka honey was examined. The minimum inhibitory concentration (MIC) of Manuka honey for four Ureaplasma urealyticum and four Ureaplasma parvum isolates was determined. Sensitivity to honey was also compared to clinical isolates with resistance to tetracycline, macrolide and fluoroquinolone antibiotics. Finally step-wise resistance training was utilized in an attempt to induce increased tolerance to honey. The MIC was dependent on the initial bacterial load with 7·5 and 18·0% w/v honey required to inhibit U. urealyticum at 1 and 10 6 colour changing units (CCU), respectively, and 4·8 and 15·3% w/v required to inhibit U. parvum at 1 and 10 6  CCU respectively. MIC values were consistently lower for U. parvum compared with U. urealyticum. Antimicrobial activity was seen against tetracycline-resistant, erythromycin-resistant and ciprofloxacin-resistant isolates at 10 5  CCU. No resistance to honey was observed with 50 consecutive challenges at increasing concentrations of honey. This is the first report of the antimicrobial activity of Manuka honey against a cell wall-free bacterial pathogen. The antimicrobial activity was retained against antibiotic-resistant strains and it was not possible to generate resistant mutants. Manuka honey is known to have a broad spectrum of antimicrobial activity, with the bacterial cell wall being suggested as a predominant site of action. This study has demonstrated that Manuka honey has activity against Ureaplasma spp., a genus of cell wall-free bacteria which are intrinsically resistant to many available antibiotics making treatment inherently difficult. This is the first report of the antimicrobial activity of Manuka honey against a bacterial pathogen, in the absence of a cell well and opens scope for the use of components of Manuka honey as a therapeutic among Ureaplasma infections. © 2016 The Society for Applied Microbiology.

  16. Patterns and sources of fecal coliform bacteria in three streams in Virginia, 1999-2000

    USGS Publications Warehouse

    Hyer, Kenneth; Moyer, Douglas

    2003-01-01

    Surface-water impairment by fecal coliform bacteria is a water-quality issue of national scope and importance. In Virginia, more than 175 stream segments are on the Commonwealth's 1998 303(d) list of impaired waters because of elevated concentrations of fecal coliform bacteria. These fecal coliform-impaired stream segments require the development of total maximum daily load (TMDL) and associated implementation plans, but accurate information on the sources contributing these bacteria usually is lacking. The development of defendable fecal coliform TMDLs and management plans can benefit from reliable information on the bacteria sources that are responsible for the impairment. Bacterial source tracking (BST) recently has emerged as a powerful tool for identifying the sources of fecal coliform bacteria that impair surface waters. In a demonstration of BST technology, three watersheds on Virginia's 1998 303(d) list with diverse land-use practices (and potentially diverse bacteria sources) were studied. Accotink Creek is dominated by urban land uses, Christians Creek by agricultural land uses, and Blacks Run is affected by both urban and agricultural land uses. During the 20-month field study (March 1999?October 2000), water samples were collected from each stream during a range of flow conditions and seasons. For each sample, specific conductance, dissolved oxygen concentration, pH, turbidity, flow, and water temperature were measured. Fecal coliform concentrations of each water sample were determined using the membrane filtration technique. Next, Escherichia coli (E. coli) were isolated from the fecal coliform bacteria and their sources were identified using ribotyping (a method of 'genetic fingerprinting'). Study results provide enhanced understanding of the concentrations and sources of fecal coliform bacteria in these three watersheds. Continuum sampling (sampling along the length of the streams) indicated that elevated concentrations of fecal coliform bacteria

  17. Salmonella enterica Serovar Enteritidis Antimicrobial Peptide Resistance Genes Aid in Defense against Chicken Innate Immunity, Fecal Shedding, and Egg Deposition

    PubMed Central

    McKelvey, Jessica A.; Yang, Ming; Jiang, Yanhua

    2014-01-01

    Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major etiologic agent of nontyphoid salmonellosis in the United States. S. Enteritidis persistently and silently colonizes the intestinal and reproductive tract of laying hens, resulting in contaminated poultry products. The consumption of contaminated poultry products has been identified as a significant risk factor for human salmonellosis. To understand the mechanisms S. Enteritidis utilizes to colonize and persist in laying hens, we used selective capture of transcribed sequences to identify genes overexpressed in the HD11 chicken macrophage cell line and in primary chicken oviduct epithelial cells. From the 15 genes found to be overexpressed in both cell types, we characterized the antimicrobial peptide resistance (AMPR) genes, virK and ybjX, in vitro and in vivo. In vitro, AMPR genes were required for natural morphology, motility, secretion, defense against detergents such as EDTA and bile salts, and resistance to antimicrobial peptides polymyxin B and avian β-defensins. From this, we inferred the AMPR genes play a role in outer membrane stability and/or modulation. In the intestinal tract, AMPR genes were involved in early intestinal colonization and fecal shedding. In the reproductive tract, virK was required in early colonization whereas a deletion of ybjX caused prolonged ovary colonization and egg deposition. Data from the present study indicate that AMPR genes are differentially utilized in various host environments, which may ultimately assist S. Enteritidis in persistent and silent colonization of chickens. PMID:25267840

  18. Micro-zooplankton grazing as a means of fecal bacteria removal in stormwater BMPs.

    PubMed

    Burtchett, Jade M; Mallin, Michael A; Cahoon, Lawrence B

    2017-06-01

    A priority for environmental managers is control of stormwater runoff pollution, especially fecal microbial pollution. This research was designed to determine if fecal bacterial grazing by micro-zooplankton is a significant control on fecal bacteria in aquatic best management practices (BMPs); if grazing differs between a wet detention pond and a constructed wetland; and if environmental factors enhance grazing. Both 3-day grazing tests and 24-h dilution assays were used to determine grazing differences between the two types of BMP. Micro-zooplankton grazing was a stronger bacteria removal mechanism in stormwater wetlands rich in aquatic vegetation compared to a standard wet detention pond, although grazing was important in detention ponds as well. Our experiments indicated that the majority of grazers that fed on fecal bacteria were <20 μm in size. Grazing rates were positively correlated with fecal coliform abundance and increased water temperatures. Enumeration of grazers demonstrated that protozoans were significantly more abundant among wetland vegetation than in open water, and open wetland waters contained more flagellates and dinoflagellates than open wet detention pond waters. Grazing on fecal bacteria in BMPs is enhanced by aquatic vegetation, and grazing in aquatic BMPs in warmer climates should be greater than in cooler climates.

  19. The global threat of antimicrobial resistance: science for intervention

    PubMed Central

    Roca, I.; Akova, M.; Baquero, F.; Carlet, J.; Cavaleri, M.; Coenen, S.; Cohen, J.; Findlay, D.; Gyssens, I.; Heure, O.E.; Kahlmeter, G.; Kruse, H.; Laxminarayan, R.; Liébana, E.; López-Cerero, L.; MacGowan, A.; Martins, M.; Rodríguez-Baño, J.; Rolain, J.-M.; Segovia, C.; Sigauque, B.; Taconelli, E.; Wellington, E.; Vila, J.

    2015-01-01

    In the last decade we have witnessed a dramatic increase in the proportion and absolute number of bacterial pathogens resistant to multiple antibacterial agents. Multidrug-resistant bacteria are currently considered as an emergent global disease and a major public health problem. The B-Debate meeting brought together renowned experts representing the main stakeholders (i.e. policy makers, public health authorities, regulatory agencies, pharmaceutical companies and the scientific community at large) to review the global threat of antibiotic resistance and come up with a coordinated set of strategies to fight antimicrobial resistance in a multifaceted approach. We summarize the views of the B-Debate participants regarding the current situation of antimicrobial resistance in animals and the food chain, within the community and the healthcare setting as well as the role of the environment and the development of novel diagnostic and therapeutic strategies, providing expert recommendations to tackle the global threat of antimicrobial resistance. PMID:26029375

  20. Antimicrobial resistance and its association with tolerance to heavy metals in agriculture production.

    PubMed

    Yu, Zhongyi; Gunn, Lynda; Wall, Patrick; Fanning, Séamus

    2017-06-01

    Antimicrobial resistance is a recognized public health challenge that since its emergence limits the therapeutic options available to veterinarians and clinicians alike, when treatment is warranted. This development is further compounded by the paucity of new antibiotics. The agri-food industry benefits from the availability of antimicrobial compounds for food-animal production and crop protection. Nonetheless, their improper use can result in the selection for bacteria that are phenotypically resistant to these compounds. Another class of agents used in agriculture includes various cationic metals that can be included in animal diets as nutritional supplements or spread on pastures to support crop growth and protection. Heavy metals, in particular, are giving rise to concerns among public health professionals, as they can persist in the environment remaining stable for prolonged periods. Moreover, bacteria can also exhibit resistance to these chemical elements and the genes encoding this phenotype can be physically localized to plasmids that may also contain one or more antimicrobial resistance-encoding gene(s). This paper reviews our current understanding of the role that bacteria play in expressing resistance to heavy metals. It will describe how heavy metals are used in agri-food production, and explore evidence available to link resistance to heavy metals and antimicrobial compounds. In addition, possible solutions to reduce the impact of heavy metal resistance are also discussed, including using organic minerals and reducing the level of trace minerals in animal feed rations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Probing minority population of antibiotic-resistant bacteria.

    PubMed

    Huang, Tianxun; Zheng, Yan; Yan, Ya; Yang, Lingling; Yao, Yihui; Zheng, Jiaxin; Wu, Lina; Wang, Xu; Chen, Yuqing; Xing, Jinchun; Yan, Xiaomei

    2016-06-15

    The evolution and spread of antibiotic-resistant pathogens has become a major threat to public health. Advanced tools are urgently needed to quickly diagnose antibiotic-resistant infections to initiate appropriate treatment. Here we report the development of a highly sensitive flow cytometric method to probe minority population of antibiotic-resistant bacteria via single cell detection. Monoclonal antibody against TEM-1 β-lactamase and Alexa Fluor 488-conjugated secondary antibody were used to selectively label resistant bacteria green, and nucleic acid dye SYTO 62 was used to stain all the bacteria red. A laboratory-built high sensitivity flow cytometer (HSFCM) was applied to simultaneously detect the side scatter and dual-color fluorescence signals of single bacteria. By using E. coli JM109/pUC19 and E. coli JM109 as the model systems for antibiotic-resistant and antibiotic-susceptible bacteria, respectively, as low as 0.1% of antibiotic-resistant bacteria were accurately quantified. By monitoring the dynamic population change of a bacterial culture with the administration of antibiotics, we confirmed that under the antimicrobial pressure, the original low population of antibiotic-resistant bacteria outcompeted susceptible strains and became the dominant population after 5hours of growth. Detection of antibiotic-resistant infection in clinical urine samples was achieved without cultivation, and the bacterial load of susceptible and resistant strains can be faithfully quantified. Overall, the HSFCM-based quantitative method provides a powerful tool for the fundamental studies of antibiotic resistance and holds the potential to provide rapid and precise guidance in clinical therapies. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Antimicrobial-Resistance Genetic Markers in Potentially Pathogenic Gram Positive Cocci Isolated from Brazilian Soft Cheese.

    PubMed

    Resende, Juliana Alves; Fontes, Cláudia Oliveira; Ferreira-Machado, Alessandra Barbosa; Nascimento, Thiago César; Silva, Vânia Lúcia; Diniz, Cláudio Galuppo

    2018-02-01

    Although most Brazilian dairy products meet high technological standards, there are quality issues regarding milk production, which may reduce the final product quality. Several microbial species may contaminate milk during manufacture and handling. If antimicrobial usage remains uncontrolled in dairy cattle, the horizontal transfer of antimicrobial resistance genes in foodstuffs may be of particular concern for both food producers and dairy industry. This study focused on the evaluation of putative Gram positive cocci in Minas cheese and of antimicrobial and biocide resistance genes among the isolated bacteria. Representative samples of 7 different industrially trademarked Minas cheeses (n = 35) were processed for selective culture and isolation of Gram positive cocci. All isolated bacteria were identified by DNA sequencing of the 16S rRNA gene. Antimicrobial resistance genes were screened by PCR. Overall, 208 strains were isolated and identified as follows: Enterococcus faecalis (47.6%), Macrococcus caseolyticus (18.3%), Enterococcus faecium (11.5%), Enterococcus caseliflavus (7.7%), Staphylococcus haemolyticus (7.2%), Staphylococcus aureus (4.3%), Staphylococcus epidermidis (2.9%), and Enterococcus hirae (0.5%). The genetic markers mecA (78.0%) and smr (71.4%) were the most prevalent, but others were also detected, such as blaZ (65.2%), msrA (60.9%), msrB (46.6%), linA (54.7%), and aacA-aphD (47.6%). The occurrence of opportunist pathogenic bacteria harboring antimicrobial resistance markers in the cheese samples are of special concern, since these bacteria are not considered harmful contaminating agents according to the Brazilian sanitary regulations. However, they are potentially pathogenic bacteria and the cheese may be considered a reservoir for antimicrobial resistance genes available for horizontal transfer through the food chain, manufacturing personnel and consumers. © 2018 Institute of Food Technologists®.

  3. Predicting Fecal Indicator Bacteria Fate and Removal in Urban Stormwater at the Watershed Scale

    NASA Astrophysics Data System (ADS)

    Wolfand, J.; Hogue, T. S.; Luthy, R. G.

    2016-12-01

    Urban stormwater is a major cause of water quality impairment, resulting in surface waters that fail to meet water quality standards and support their designated uses. Of the many stormwater pollutants, fecal indicator bacteria are particularly important to track because they are directly linked to pathogens which jeopardize public health; yet, their fate and transport in urban stormwater is poorly understood. Monitoring fecal bacteria in stormwater is possible, but due to the high variability of fecal indicators both spatially and temporally, single grab or composite samples do not fully capture fecal indicator loading. Models have been developed to predict fecal indicator bacteria at the watershed scale, but they are often limited to agricultural areas, or areas that receive frequent rainfall. Further, it is unclear whether best management practices (BMPs), such as bioretention or engineered wetlands, are able to reduce bacteria to meet water quality standards at watershed outlets. This research seeks to develop a model to predict fecal indicator bacteria in urban stormwater in a semi-arid climate at the watershed scale. Using the highly developed Ballona Creek watershed (89 mi2) located in Los Angeles County as a case study, several existing mechanistic models are coupled with a hydrologic model to predict fecal indicator concentrations (E. coli, enterococci, fecal coliform, and total coliform) at the outfall of Ballona Creek watershed, Santa Monica Bay. The hydrologic model was developed using InfoSWMM Sustain, calibrated for flow from WY 1998-2006 (NSE = 0.94; R2 = 0.95), and validated from WY 2007-2015 (NSE = 0.93; R2 = 0.95). The developed coupled model is being used to predict fecal indicator fate and transport and evaluate how BMPs can be optimized to reduce fecal indicator loading to surface waters and recreational beaches.

  4. Molecular studies of fecal anaerobic commensal bacteria in acute diarrhea in children.

    PubMed

    Balamurugan, Ramadass; Janardhan, Harish P; George, Sarah; Raghava, M Venkata; Muliyil, Jayaprakash; Ramakrishna, Balakrishnan S

    2008-05-01

    The commensal bacterial flora of the colon may undergo changes during diarrhea, owing to colonization of the intestine by pathogens and to rapid intestinal transit. This study used molecular methods to determine changes in the composition of selected commensal anaerobic bacteria during and after acute diarrhea in children. Fecal samples were obtained from 46 children with acute diarrhea in a rural community during an episode of acute diarrhea, immediately after recovery from diarrhea, and 3 months after recovery. DNA was extracted and quantitative polymerase chain reaction using SYBR green and genus- and species-specific primers targeting 16S rDNA were undertaken to quantitate the following groups of bacteria: Bifidobacterium spp., Bifidobacterium longum group, Bacteroides-Prevotella group, Bacteroides fragilis, Lactobacillus acidophilus group, Faecalibacterium prauznitzii, and Eubacterium rectale, relative to amplification of universal bacterial domain 16S rDNA. Bacteria belonging to the Bacteroides-Prevotella-Porphyromonas group, E rectale, L acidophilus, and F prauznitzii groups were low during acute diarrhea compared with their levels after recovery from diarrhea. The pattern was similar in rotavirus diarrhea and nonrotavirus diarrhea. Administration of amylase-resistant maize starch as adjuvant therapy was associated with lower levels of F prauznitzii at the time of recovery but did not lead to other changes in the floral pattern. Specific classes of fecal bacteria are lower during episodes of acute diarrhea in children than during periods of normal gastrointestinal health, suggesting specific alterations in the flora during diarrhea.

  5. Differentiation of farmed and wild turbot (Psetta maxima): proximate chemical composition, fatty acid profile, trace minerals and antimicrobial resistance of contaminant bacteria.

    PubMed

    Martínez, B; Miranda, J M; Nebot, C; Rodriguez, J L; Cepeda, A; Franco, C M

    2010-10-01

    The proximate, cholesterol, fatty acid and trace mineral compositions in the flesh of farmed and wild turbot (Psetta maxima) were evaluated. Additionally, the potential influence of the use of antimicrobial agents in the bacteria carried by farmed turbot was investigated. For this purpose, a total of 144 Pseudomonas spp. and 127 Aeromonas spp. were isolated and tested for their susceptibility to 12 antimicrobials by a disk diffusion method. Farmed turbot contained higher fat, cholesterol and calories as well as lower moisture content than its wild counterpart. The fatty acid profile of farmed turbot included higher levels of myristic, pentadecanoic, palmitoleic, gadoleic, cetoleic, linoleic, linolenic, stearidonic, eicosadienoic and eicosapentaenoic acids, and lower levels of stearic, arachidonic, docosapentaenoic and docosahexaenoic acids than its wild counterpart. The proportions of polyunsaturated fatty acids and n-3/n-6 ratios were higher in wild turbot than in farmed turbot. With respect to trace minerals, no toxic levels were found, and higher amounts of Cd, Co, Cu, Fe, Mn, Pb and Zn, as well as lower amounts of Cr, were found in farmed turbot relative to wild turbot. The antimicrobial resistance of Pseudomonas spp. and Aeromonas spp. were quite similar, with only the trimethoprim-sulfamethoxazole resistance of Aeromonas spp. isolated from farmed turbot being higher than those isolated from wild turbot. In the case of ampicillin, Pseudomonas spp. isolated from wild turbot showed higher resistance levels than those of their counterparts isolated from farmed turbot. In conclusion, the nutritional parameters of wild turbot are more adequate with respect to nutritional recommendations, while no differences were observed in food safety derived from trace mineral concentrations or the antimicrobial resistance of bacteria isolated from wild and farmed turbot.

  6. Screening of plant extracts for antimicrobial activity against bacteria and yeasts with dermatological relevance.

    PubMed

    Weckesser, S; Engel, K; Simon-Haarhaus, B; Wittmer, A; Pelz, K; Schempp, C M

    2007-08-01

    There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobial agents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata (dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia officinalis (supercritical carbon dioxide [CO2] extracts). Additionally, the following characteristic plant substances were tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic acid, harpagoside, boswellic acid and gentiopicroside. The extracts and compounds were tested against 29 aerobic and anaerobic bacteria and yeasts in the agar dilution test. U. barbata-extract and usnic acid were the most active compounds, especially in anaerobic bacteria. Usnea CO2-extract effectively inhibited the growth of several Gram-positive bacteria like Staphylococcus aureus (including methicillin-resistant strains - MRSA), Propionibacterium acnes and Corynebacterium species. Growth of the dimorphic yeast Malassezia furfur was also inhibited by Usnea-extract. Besides the Usnea-extract, Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to be effective against a panel of bacteria. It is concluded that due to their antimicrobial effects some of the plant extracts may be used for the topical treatment of skin disorders like acne vulgaris and seborrhoic eczema.

  7. Antibiotic resistance genes and residual antimicrobials in cattle feedlot surface soil

    USDA-ARS?s Scientific Manuscript database

    Cattle feedlot soils receive manure containing both antibiotic residues and antibiotic resistant bacteria. The fates of these constituents are largely unknown with potentially serious consequences for increased antibiotic resistance in the environment. Determine if common antimicrobials (tetracycl...

  8. Will new antimicrobials overcome resistance among Gram-negatives?

    PubMed

    Bassetti, Matteo; Ginocchio, Francesca; Mikulska, Małgorzata; Taramasso, Lucia; Giacobbe, Daniele Roberto

    2011-10-01

    The spread of resistance among Gram-positive and Gram-negative bacteria represents a growing challenge for the development of new antimicrobials. The pace of antibiotic drug development has slowed during the last decade and, especially for Gram-negatives, clinicians are facing a dramatic shortage in the availability of therapeutic options to face the emergency of the resistance problem throughout the world. In this alarming scenario, although there is a shortage of compounds reaching the market in the near future, antibiotic discovery remains one of the keys to successfully stem and maybe overcome the tide of resistance. Analogs of already known compounds and new agents belonging to completely new classes of antimicrobials are in early stages of development. Novel and promising anti-Gram-negative antimicrobials belong both to old (cephalosporins, carbapenems, β-lactamase inhibitors, monobactams, aminoglycosides, polymyxin analogues and tetracycline) and completely new antibacterial classes (boron-containing antibacterial protein synthesis inhibitors, bis-indoles, outer membrane synthesis inhibitors, antibiotics targeting novel sites of the 50S ribosomal subunit and antimicrobial peptides). However, all of these compounds are still far from being introduced into clinical practice. Therefore, infection control policies and optimization in the use of already existing molecules are still the most effective approaches to reduce the spread of resistance and preserve the activity of antimicrobials.

  9. Global Governance Mechanisms to Address Antimicrobial Resistance.

    PubMed

    Padiyara, Ponnu; Inoue, Hajime; Sprenger, Marc

    2018-01-01

    Since their discovery, antibiotics, and more broadly, antimicrobials, have been a cornerstone of modern medicine. But the overuse and misuse of these drugs have led to rising rates of antimicrobial resistance, which occurs when bacteria adapt in ways that render antibiotics ineffective. A world without effective antibiotics can have drastic impacts on population health, global development, and the global economy. As a global common good, antibiotic effectiveness is vulnerable to the tragedy of the commons, where a shared limited resource is overused by a community when each individual exploits the finite resource for their own benefit. A borderless threat like antimicrobial resistance requires global governance mechanisms to mitigate its emergence and spread, and it is the responsibility of all countries and relevant multilateral organizations. These mechanisms can be in the form of legally binding global governance mechanisms such as treaties and regulatory standards or nonbinding mechanisms such as political declarations, resolutions, or guidelines. In this article, we argue that while both are effective methods, the strong, swift, and coordinated action needed to address rising rates of antimicrobial resistance will be better served through legally binding governance mechanisms.

  10. Strategic measures for the control of surging antimicrobial resistance in Hong Kong and mainland of China

    PubMed Central

    Cheng, Vincent CC; Wong, Sally CY; Ho, Pak-Leung; Yuen, Kwok-Yung

    2015-01-01

    Antimicrobial-resistant bacteria are either highly prevalent or increasing rapidly in Hong Kong and China. Treatment options for these bacteria are generally limited, less effective and more expensive. The emergence and dynamics of antimicrobial resistance genes in bacteria circulating between animals, the environment and humans are not entirely known. Nonetheless, selective pressure by antibiotics on the microbiomes of animal and human, and their associated environments (especially farms and healthcare institutions), sewage systems and soil are likely to confer survival advantages upon bacteria with antimicrobial-resistance genes, which may be further disseminated through plasmids or transposons with integrons. Therefore, antibiotic use must be tightly regulated to eliminate such selective pressure, including the illegalization of antibiotics as growth promoters in animal feed and regulation of antibiotic use in veterinary practice and human medicine. Heightened awareness of infection control measures to reduce the risk of acquiring resistant bacteria is essential, especially during antimicrobial use or institutionalization in healthcare facilities. The transmission cycle must be interrupted by proper hand hygiene, environmental cleaning, avoidance of undercooked or raw food and compliance with infection control measures by healthcare workers, visitors and patients, especially during treatment with antibiotics. In addition to these routine measures, proactive microbiological screening of hospitalized patients with risk factors for carrying resistant bacteria, including history of travel to endemic countries, transfer from other hospitals, and prolonged hospitalization; directly observed hand hygiene before oral intake of drugs, food and drinks; and targeted disinfection of high-touch or mutual-touch items, such as bed rails and bed curtains, are important. Transparency of surveillance data from each institute for public scrutiny provides an incentive for

  11. Characterization of fecal vancomycin-resistant enterococci with acquired and intrinsic resistance mechanisms in wild animals, Spain.

    PubMed

    Lozano, Carmen; Gonzalez-Barrio, David; Camacho, Maria Cruz; Lima-Barbero, Jose Francisco; de la Puente, Javier; Höfle, Ursula; Torres, Carmen

    2016-11-01

    The objectives were to evaluate the presence of vancomycin-resistant enterococci with acquired (VRE-a) and intrinsic (VRE-i) resistance mechanisms in fecal samples from different wild animals, and analyze their phenotypes and genotypes of antimicrobial resistance. A total of 348 cloacal/rectal samples from red-legged partridges (127), white storks (81), red kites (59), and wild boars (81) (June 2014/February 2015) were inoculated in Slanetz-Bartley agar supplemented with vancomycin (4 μg/mL). We investigated the susceptibility to 12 antimicrobials and the presence of 19 antimicrobial resistance and five virulence genes. In addition, we performed multilocus sequence typing, detection of IS16 and studied Tn1546 structure. One VRE-a isolate was identified in one wild boar. This isolate was identified as Enterococcus faecium, harbored vanA gene included into Tn1546 (truncated with IS1542/IS1216), and belonged to the new ST993. This isolate contained the erm(A), erm(B), tet(M), dfrG, and dfrK genes. Neither element IS16 nor the studied virulence genes were detected. Ninety-six VRE-i isolates were identified (89 Enterococcus gallinarum and seven Enterococcus casseliflavus), with the following prevalence: red kites (71.2 %), white storks (46.9 %), red-legged partridges (7.9 %), and wild boars (4.9 %). Most E. gallinarum isolates showed resistance to tetracycline (66.3 %) and/or erythromycin (46.1 %). High-level resistance to aminoglycosides was present among our VRE-i isolates: kanamycin (22.9 %), streptomycin (11.5 %), and gentamicin (9.4 %). In general, VRE-i isolates of red kites showed higher rates of resistance for non-glycopeptide agents than those of other animal species. The dissemination of acquired resistance mechanisms in natural environments could have implications in the global spread of resistance with public health implications.

  12. Antimicrobial and disinfectant resistance of Escherichia coli isolated from giant pandas.

    PubMed

    Guo, L; Long, M; Huang, Y; Wu, G; Deng, W; Yang, X; Li, B; Meng, Y; Cheng, L; Fan, L; Zhang, H; Zou, L

    2015-07-01

    study highlights the need for regularly monitoring the antimicrobial and disinfectant resistance in bacteria from giant pandas. © 2015 The Society for Applied Microbiology.

  13. Proline-rich antimicrobial peptides: potential therapeutics against antibiotic-resistant bacteria.

    PubMed

    Li, Wenyi; Tailhades, Julien; O'Brien-Simpson, Neil M; Separovic, Frances; Otvos, Laszlo; Hossain, M Akhter; Wade, John D

    2014-10-01

    The increasing resistance of pathogens to antibiotics causes a huge clinical burden that places great demands on academic researchers and the pharmaceutical industry for resolution. Antimicrobial peptides, part of native host defense, have emerged as novel potential antibiotic alternatives. Among the different classes of antimicrobial peptides, proline-rich antimicrobial peptides, predominantly sourced from insects, have been extensively investigated to study their specific modes of action. In this review, we focus on recent developments in these peptides. They show a variety of modes of actions, including mechanism shift at high concentration, non-lytic mechanisms, as well as possessing different intracellular targets and lipopolysaccharide binding activity. Furthermore, proline-rich antimicrobial peptides display the ability to not only modulate the immune system via cytokine activity or angiogenesis but also possess properties of penetrating cell membranes and crossing the blood brain barrier suggesting a role as potential novel carriers. Ongoing studies of these peptides will likely lead to the development of more potent antimicrobial peptides that may serve as important additions to the armoury of agents against bacterial infection and drug delivery.

  14. Concentrations of fecal coliform bacteria in creeks, Anchorage, Alaska, August and September 1998

    USGS Publications Warehouse

    Dorava, Joseph M.; Love, Andra

    1999-01-01

    Water samples were collected from five creeks in undeveloped, semi-developed, and developed areas of Anchorage, Alaska, during August and September 1998 to determine concentrations of fecal coliform bacteria. In undeveloped areas of Ship, Chester, and Campbell Creeks, and the semi-developed area of Rabbit Creek, concentrations of fecal coliform bacteria ranged from less than 1 to 16 colonies per 100 milliliters of water. In the semi-developed area of Little Rabbit Creek, concentrations ranged from 30 to 860 colonies per 100 milliliters of water. In developed areas of the creeks, concentrations of fecal coliform bacteria ranged from 6 to 80 colonies per 100 milliliters of water.

  15. Canadian integrated program for antimicrobial resistance surveillance: Retail food highlights, 2003-2012.

    PubMed

    Avery, B P; Parmley, E J; Reid-Smith, R J; Daignault, D; Finley, R L; Irwin, R J

    2014-11-07

    The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) is a collaborative, integrated program designed to track antimicrobial resistance (AMR) among enteric bacteria isolated from various livestock commodities along the food-producing continuum ("farm to fork") and in humans. To provide a summary of the prevalence and trends in AMR among select bacteria isolated from raw, fresh chicken, pork, and beef in 2012 at the retail food level and to link these data with other findings from CIPARS. Meat samples were collected from randomly selected geographic areas across Canada weighted by population for subsequent isolation of bacteria and interpretation of the associated AMR profiles. Salmonella, Campylobacter and generic Escherichia coli ( E. coli ) were tested in chicken, and E. coli was tested in beef and pork. Data were analyzed for 2012 and temporal and regional trends were examined between 2003 and 2012 by province/region. Overall, resistance levels to Salmonella in retail chicken varied widely by region and year. For example, ceftiofur resistance to Salmonella in retail chicken was significantly lower in 2012 than in 2004 in Ontario and in Québec; however, among all regions sampled, resistance was significantly higher in 2012 compared to 2006. Across all regions sampled, resistance to Campylobacter in retail chicken was relatively low in 2012 (<16%) with the exception of tetracycline resistance. In 2012, ciprofloxacin resistance to Campylobacter in chicken declined in British Columbia but significantly increased in Ontario, compared to 2011. In 2012, β-lactam resistance to E. coli in retail beef remained low (≤1%) and was also relatively low comparable to previous years in pork. In Canada, as is the case worldwide, there is evidence of resistance to medically important antimicrobials among bacteria from retail meats. Resistance among organisms isolated from poultry, beef, and pork at the retail food level is characterized by wide

  16. Survival of Salmonella spp. and fecal indicator bacteria in Vietnamese biogas digesters receiving pig slurry.

    PubMed

    Huong, Luu Quynh; Forslund, Anita; Madsen, Henry; Dalsgaard, Anders

    2014-09-01

    Small-scale biogas digesters are widely promoted worldwide as a sustainable technology to manage livestock manure. In Vietnam, pig slurry is commonly applied to biogas digesters for production of gas for electricity and cooking with the effluent being used to fertilize field crops, vegetables and fish ponds. Slurry may contain a variety of zoonotic pathogens, e.g. Salmonella spp., which are able to cause disease in humans either through direct contact with slurry or by fecal contamination of water and foods. The objective of this study was to evaluate the survival of Salmonella spp. and the fecal indicator bacteria, enterococci, E. coli, and spores of Clostridium perfringens in biogas digesters operated by small-scale Vietnamese pig farmers. The serovar and antimicrobial susceptibility of the Salmonella spp. isolated were also established. The study was conducted in 12 farms (6 farms with and 6 farms without toilet connected) located in Hanam province, Vietnam. Sampling of pig slurry and biogas effluent was done during two seasons. Results showed that the concentration of enterococci, E. coli, and Clostridium perfringens spores was overall reduced by only 1-2 log10-units in the biogas digesters when comparing raw slurry and biogas effluent. Salmonella spp. was found in both raw slurry and biogas effluent. A total of 19 Salmonella serovars were identified, with the main serovars being Salmonella Typhimurium (55/138), Salmonella enterica serovar 4,[5],12:i:- (19/138), Salmonella Weltevreden (9/138) and Salmonella Rissen (9/138). The Salmonella serovars showed similar antimicrobial resistance patterns to those previously reported from Vietnam. When promoting biogas, farmers should be made aware that effluent should only be used as fertilizer for crops not consumed raw and that indiscriminate discharge of effluent are likely to contaminate water recipients, e.g. drinking water sources, with pathogens. Relevant authorities should promote safe animal manure management

  17. Consumer Exposure to Antimicrobial Resistant Bacteria From Food at Swiss Retail Level

    PubMed Central

    Jans, Christoph; Sarno, Eleonora; Collineau, Lucie; Meile, Leo; Stärk, Katharina D. C.; Stephan, Roger

    2018-01-01

    Background: Antimicrobial resistance (AMR) in bacteria is an increasing health concern. The spread of AMR bacteria (AMRB) between animals and humans via the food chain and the exchange of AMR genes requires holistic approaches for risk mitigation. The AMRB exposure of humans via food is currently only poorly understood leaving an important gap for intervention design. Method: This study aimed to assess AMRB prevalence in retail food and subsequent exposure of Swiss consumers in a systematic literature review of data published between 1996 and 2016 covering the Swiss agriculture sector and relevant imported food. Results: Data from 313 out of 9,473 collected studies were extracted yielding 122,438 food samples and 38,362 bacteria isolates of which 30,092 samples and 8,799 isolates were AMR positive. A median AMRB prevalence of >50% was observed for meat and seafood harboring Campylobacter, Enterococcus, Salmonella, Escherichia coli, Listeria, and Vibrio spp. and to a lesser prevalence for milk products harboring starter culture bacteria. Gram-negative AMRB featured predominantly AMR against aminoglycosides, cephalosporins, fluoroquinolones, penicillins, sulfonamides, and tetracyclines observed at AMR exposures scores of levels 1 (medium) and 2 (high) for Campylobacter, Salmonella, E. coli in meat as well as Vibrio and E. coli in seafood. Gram-positive AMRB featured AMR against glycoproteins, lincosamides, macrolides and nitrofurans for Staphylococcus and Enterococcus in meat sources, Staphylococcus in seafood as well as Enterococcus and technologically important bacteria (incl. starters) in fermented or processed dairy products. Knowledge gaps were identified for AMR prevalence in dairy, plant, fermented meat and novel food products and for the role of specific indicator bacteria (Staphylococcus, Enterococcus), starter culture bacteria and their mobile genetic elements in AMR gene transfer. Conclusion: Raw meat, milk, seafood, and certain fermented dairy products

  18. Antimicrobial Activity of Cationic Antimicrobial Peptides against Gram-Positives: Current Progress Made in Understanding the Mode of Action and the Response of Bacteria.

    PubMed

    Omardien, Soraya; Brul, Stanley; Zaat, Sebastian A J

    2016-01-01

    Antimicrobial peptides (AMPs) have been proposed as a novel class of antimicrobials that could aid the fight against antibiotic resistant bacteria. The mode of action of AMPs as acting on the bacterial cytoplasmic membrane has often been presented as an enigma and there are doubts whether the membrane is the sole target of AMPs. Progress has been made in clarifying the possible targets of these peptides, which is reported in this review with as focus gram-positive vegetative cells and spores. Numerical estimates are discussed to evaluate the possibility that targets, other than the membrane, could play a role in susceptibility to AMPs. Concerns about possible resistance that bacteria might develop to AMPs are addressed. Proteomics, transcriptomics, and other molecular techniques are reviewed in the context of explaining the response of bacteria to the presence of AMPs and to predict what resistance strategies might be. Emergent mechanisms are cell envelope stress responses as well as enzymes able to degrade and/or specifically bind (and thus inactivate) AMPs. Further studies are needed to address the broadness of the AMP resistance and stress responses observed.

  19. Persistence of resistance plasmids carried by beta-hemolytic E. coli when maintained in a continous-flow fermentation system without antimicrobial selection pressure

    USDA-ARS?s Scientific Manuscript database

    Multi-drug resistant bacteria are an increasing threat to human and animal health; to combat this threat, a reduction in the use of antimicrobials has been recommended. For reduction in drug usage to reduce the incidence of resistant bacteria, this requires that maintaining antimicrobial resistance...

  20. Enteric Viruses and Fecal Bacteria Indicators to Assess Groundwater Quality and Suitability for Irrigation

    PubMed Central

    De Giglio, Osvalda; Caggiano, Giuseppina; Bagordo, Francesco; Barbuti, Giovanna; Brigida, Silvia; Lugoli, Federica; Grassi, Tiziana; La Rosa, Giuseppina; Lucentini, Luca; Uricchio, Vito Felice; De Donno, Antonella; Montagna, Maria Teresa

    2017-01-01

    According to Italian Ministerial Decree No. 185 of 12 June 2003, water is considered suitable for irrigation if levels of fecal bacteria (i.e., Escherichia coli and Salmonella) are within certain parameters. The detection of other microorganisms is not required. The aim of this study is to determine the bacteriological quality of groundwater used for irrigation and the occurrence of enteric viruses (Norovirus, Enterovirus, Rotavirus, Hepatovirus A), and to compare the presence of viruses with the fecal bacteria indicators. A total of 182 wells was analyzed. Widespread fecal contamination of Apulian aquifers was detected (141 wells; 77.5%) by the presence of fecal bacteria (i.e., E. coli, Salmonella, total coliforms, and enterococci). Considering bacteria included in Ministerial Decree No. 185, the water from 35 (19.2%) wells was unsuitable for irrigation purposes. Among 147 wells with water considered suitable, Norovirus, Rotavirus, and Enterovirus were detected in 23 (15.6%) wells. No Hepatovirus A was isolated. Consequently, 58 wells (31.9%) posed a potential infectious risk for irrigation use. This study revealed the inadequacy of fecal bacteria indicators to predict the occurrence of viruses in groundwater and it is the first in Italy to describe the presence of human rotaviruses in well water used for irrigation. PMID:28538682

  1. Genetic diversity and antimicrobial resistance among isolates of Escherichia coli O157: H7 from feces and hides of super-shedders and low-shedding pen-mates in two commercial beef feedlots

    PubMed Central

    2012-01-01

    Background Cattle shedding at least 104 CFU Escherichia coli O157:H7/g feces are described as super-shedders and have been shown to increase transmission of E. coli O157:H7 to other cattle in feedlots. This study investigated relationships among fecal isolates from super-shedders (n = 162), perineal hide swab isolates (PS) from super-shedders (n = 137) and fecal isolates from low-shedder (< 104 CFU/g feces) pen-mates (n = 496) using pulsed-field gel electrophoresis (PFGE). A subsample of these fecal isolates (n = 474) was tested for antimicrobial resistance. Isolates of E. coli O157:H7 were obtained from cattle in pens (avg. 181 head) at 2 commercial feedlots in southern Alberta with each steer sampled at entry to the feedlot and prior to slaughter. Results Only 1 steer maintained super-shedder status at both samplings, although approximately 30% of super-shedders in sampling 1 had low-shedder status at sampling 2. A total of 85 restriction endonuclease digestion clusters (REPC; 90% or greater similarity) and 86 unique isolates (< 90% similarity) were detected, with the predominant REPC (30% of isolates) being isolated from cattle in all feedlot pens, although it was not associated with shedding status (super- or low-shedder; P = 0.94). Only 2/21 super-shedders had fecal isolates in the same REPC at both samplings. Fecal and PS isolates from individual super-shedders generally belonged to different REPCs, although fecal isolates of E. coli O157:H7 from super- and low-shedders showed greater similarity (P < 0.001) than those from PS. For 77% of super-shedders, PFGE profiles of super-shedder fecal and PS isolates were distinct from all low-shedder fecal isolates collected in the same pen. A low level of antimicrobial resistance (3.7%) was detected and prevalence of antimicrobial resistance did not differ among super- and low-shedder isolates (P = 0.69), although all super-shedder isolates with antimicrobial resistance (n = 3) were

  2. Potential Sources and Transmission of Salmonella and Antimicrobial Resistance in Kampala, Uganda

    PubMed Central

    Afema, Josephine A.; Byarugaba, Denis K.; Shah, Devendra H.; Atukwase, Esther; Nambi, Maria; Sischo, William M.

    2016-01-01

    In sub‒Saharan Africa, non‒typhoidal Salmonellae (NTS) cause invasive disease particularly in children and HIV infected adults, but the disease epidemiology is poorly understood. Between 2012 and 2013, we investigated NTS sources and transmission in Kampala. We detected Salmonella in 60% of the influent and 60% of the effluent samples from a wastewater treatment plant and 53.3% of the influent and 10% of the effluent samples from waste stabilization ponds that serve the human population; 40.9% of flush‒water samples from ruminant slaughterhouses, 6.6% of the poultry fecal samples from live bird markets and 4% of the fecal samples from swine at slaughter; and in 54.2% of the water samples from a channel that drains storm–water and effluents from the city. We obtained 775 Salmonella isolates, identified 32 serovars, and determined resistance to 15 antimicrobials. We genotyped common serovars using multiple‒locus variable number tandem repeats analysis or pulsed‒field gel electrophoresis. In addition, we analyzed 49 archived NTS isolates from asymptomatic livestock and human clinical cases. Salmonella from ruminant and swine sources were mostly pan‒susceptible (95%) while poultry isolates were generally more resistant. Salmonella Kentucky isolated from poultry exhibited extensive drug resistance characterized by resistance to 10 antimicrobials. Interestingly, similar genotypes of S. Kentucky but with less antimicrobial resistance (AMR) were found in poultry, human and environmental sources. The observed AMR patterns could be attributed to host or management factors associated with production. Alternatively, S. Kentucky may be prone to acquiring AMR. The factors driving AMR remain poorly understood and should be elucidated. Overall, shared genotypes and AMR phenotypes were found in NTS from human, livestock and environmental sources, suggesting zoonotic and environmental transmissions most likely occur. Information from this study could be used to control

  3. Resistance to bacteriocins produced by Gram-positive bacteria.

    PubMed

    Bastos, Maria do Carmo de Freire; Coelho, Marcus Lívio Varella; Santos, Olinda Cabral da Silva

    2015-04-01

    Bacteriocins are prokaryotic proteins or peptides with antimicrobial activity. Most of them exhibit a broad spectrum of activity, inhibiting micro-organisms belonging to different genera and species, including many bacterial pathogens which cause human, animal or plant infections. Therefore, these substances have potential biotechnological applications in either food preservation or prevention and control of bacterial infectious diseases. However, there is concern that continuous exposure of bacteria to bacteriocins may select cells resistant to them, as observed for conventional antimicrobials. Based on the models already investigated, bacteriocin resistance may be either innate or acquired and seems to be a complex phenomenon, arising at different frequencies (generally from 10(-9) to 10(-2)) and by different mechanisms, even amongst strains of the same bacterial species. In the present review, we discuss the prevalence, development and molecular mechanisms involved in resistance to bacteriocins produced by Gram-positive bacteria. These mechanisms generally involve changes in the bacterial cell envelope, which result in (i) reduction or loss of bacteriocin binding or insertion, (ii) bacteriocin sequestering, (iii) bacteriocin efflux pumping (export) and (iv) bacteriocin degradation, amongst others. Strategies that can be used to overcome this resistance are also addressed. © 2015 The Authors.

  4. Rainfall and tillage effects on transport of fecal bacteria and sex hormones 17beta-estradiol and testosterone from broiler litter applications to a Georgia Piedmont Ultisol.

    PubMed

    Jenkins, Michael B; Truman, Clint C; Siragusa, Gregory; Line, Eric; Bailey, J Stan; Frye, Jonathan; Endale, Dinku M; Franklin, Dorcas H; Schomberg, Harry H; Fisher, Dwight S; Sharpe, Ronald R

    2008-09-15

    Poultry litter provides nutrients for crop and pasture production; however, it also contains fecal bacteria, sex hormones (17beta-estradiol and testosterone) and antibiotic residues that may contaminate surface waters. Our objective was to quantify transport of fecal bacteria, estradiol, testosterone and antibiotic residues from a Cecil sandy loam managed since 1991 under no-till (NT) and conventional tillage (CT) to which either poultry litter (PL) or conventional fertilizer (CF) was applied based on the nitrogen needs of corn (Zea mays L) in the Southern Piedmont of NE Georgia. Simulated rainfall was applied for 60 min to 2 by 3-m field plots at a constant rate in 2004 and variable rate in 2005. Runoff was continuously measured and subsamples taken for determining flow-weighted concentrations of fecal bacteria, hormones, and antibiotic residues. Neither Salmonella, nor Campylobacter, nor antimicrobial residues were detected in litter, soil, or runoff. Differences in soil concentrations of fecal bacteria before and after rainfall simulations were observed only for Escherichia coli in the constant rainfall intensity experiment. Differences in flow-weighted concentrations were observed only for testosterone in both constant and variable intensity rainfall experiments, and were greatest for treatments that received poultry litter. Total loads of E. coli and fecal enterococci, were largest for both tillage treatments receiving poultry litter for the variable rainfall intensity. Load of testosterone was greatest for no-till plots receiving poultry litter under variable rainfall intensity. Poultry litter application rates commensurate for corn appeared to enhance only soil concentrations of E. coli, and runoff concentrations of testosterone above background levels.

  5. Identification and antimicrobial resistance of microflora colonizing feral pig (Sus scrofa) of Brazilian Pantanal.

    PubMed Central

    Lessa, SS; Paes, RCS; Santoro, PN; Mauro, RA; Vieira-da-Motta, O

    2011-01-01

    Antimicrobial resistance of bacteria is a worldwide problem affecting wild life by living with resistant bacteria in the environment. This study presents a discussion of outside factors environment on microflora of feral pigs (Sus scrofa) from Brazilian Pantanal. Animals had samples collected from six different body sites coming from two separated geographic areas, Nhecolandia and Rio Negro regions. With routine biochemical tests and commercial kits 516 bacteria were identified, with 240 Gram-positive, predominantly staphylococci (36) and enterococci (186) strains. Among Gram-negative (GN) bacteria the predominant specimens of Enterobacteriaceae (247) mainly represented by Serratia spp. (105), Escherichia coli (50), and Enterobacter spp. (40) and specimens not identified (7). Antimicrobial susceptibility was tested against 17 drugs by agar diffusion method. Staphylococci were negative to production of enterotoxins and TSST-1, with all strains sensitive towards four drugs and highest resistance toward ampicillin (17%). Enterococci presented the highest sensitivity against vancomycin (98%), ampicillin (94%) and tetracycline (90%), and highest resistance pattern toward oxacillin (99%), clindamycin (83%), and cotrimoxazole (54%). In GN the highest resistance was observed with Serratia marcescens against CFL (98%), AMC (66%) and AMP (60%) and all drugs was most effective against E. coli SUT, TET (100%), AMP, TOB (98%), GEN, CLO (95%), CFO, CIP (93%). The results show a new profile of oxacillin-resistant enterococci from Brazilian feral pigs and suggest a limited residue and spreading of antimicrobials in the environment, possibly because of low anthropogenic impact reflected by the drug susceptibility profile of bacteria isolated. PMID:24031689

  6. Contamination of Canadian private drinking water sources with antimicrobial resistant Escherichia coli.

    PubMed

    Coleman, Brenda L; Louie, Marie; Salvadori, Marina I; McEwen, Scott A; Neumann, Norman; Sibley, Kristen; Irwin, Rebecca J; Jamieson, Frances B; Daignault, Danielle; Majury, Anna; Braithwaite, Shannon; Crago, Bryanne; McGeer, Allison J

    2013-06-01

    Surface and ground water across the world, including North America, is contaminated with bacteria resistant to antibiotics. The consumption of water contaminated with antimicrobial resistant Escherichia coli (E. coli) has been associated with the carriage of resistant E. coli in people who drink it. To describe the proportion of drinking water samples submitted from private sources for bacteriological testing that were contaminated with E. coli resistant to antibiotics and to determine risk factors for the contamination of these water sources with resistant and multi-class resistant E. coli. Water samples submitted for bacteriological testing in Ontario and Alberta Canada were tested for E. coli contamination, with a portion of the positive isolates tested for antimicrobial resistance. Households were invited to complete questionnaires to determine putative risk factors for well contamination. Using multinomial logistic regression, the risk of contamination with E. coli resistant to one or two classes of antibiotics compared to susceptible E. coli was higher for shore wells than drilled wells (odds ratio [OR] 2.8) and higher for farms housing chickens or turkeys (OR 3.0) than properties without poultry. The risk of contamination with multi-class resistant E. coli (3 or more classes) was higher if the properties housed swine (OR 5.5) or cattle (OR 2.2) than properties without these livestock and higher if the wells were located in gravel (OR 2.4) or clay (OR 2.1) than in loam. Housing livestock on the property, using a shore well, and having a well located in gravel or clay soil increases the risk of having antimicrobial resistant E. coli in E. coli contaminated wells. To reduce the incidence of water borne disease and the transmission of antimicrobial resistant bacteria, owners of private wells need to take measures to prevent contamination of their drinking water, routinely test their wells for contamination, and use treatments that eliminate bacteria. Copyright

  7. [The importance of wildlife as reservoir of antibiotic-resistant bacteria in Bavaria--first results].

    PubMed

    Meyer, Cornelia; Heurich, Marco; Huber, Ingrid; Krause, Gladys; Ullrich, Ulrike; Fetsch, Alexandra

    2014-01-01

    The use of antimicrobial agents is responsible for the emergence and spread of antibiotic resistant bacteria. Nevertheless, multiresistant bacteria have been found in animals that have never been exposed to antimicrobial agents. Wild animals that are carriers of methicillin-resistant organisms represent a hazard since they can transmit their bacteria to other animals and to humans. In the hunting season 2009/2010 nasal swabs of 98 red deer and 109 wild boars were examined for the presence of methicillin-sensitive and methicillin-resistant staphylococci. From each wild boar methicillin-susceptible staphylococci (Staphylococcus aureus in 28% and Staphylococcus spp. in 72% of the animals) were isolated. In red deer the detection rate of Staphylococcus (S.) aureus and methicillin-susceptible staphylococci was 49% and 17%, respectively. The occurrence of S. aureus was significantly higher (p < 0.05) in red deer than in wild boars. Methicillin-resistant staphylococci were not found. However, in one third of the red deer, methicillin-resistant bacteria of the genus Enterococcus spp. and Bacillus spp. were isolated. The results of the present study indicate that wildlife, especially red deer are an important reservoir for S. aureus and that the upper respiratory tract of red deer is regularly colonised with methicillin-resistant bacteria such as Bacillus spp. and Enterococcus spp. Primarily, commensal bacteria are harmless to human health, however, red deer may be a reservoir for antibiotic-resistant bacteria.

  8. Antimicrobial Resistance and the Alternative Resources with Special Emphasis on Plant-Based Antimicrobials—A Review

    PubMed Central

    Chandra, Harish; Bishnoi, Parul; Yadav, Archana; Patni, Babita; Mishra, Abhay Prakash; Nautiyal, Anant Ram

    2017-01-01

    Indiscriminate and irrational use of antibiotics has created an unprecedented challenge for human civilization due to microbe’s development of antimicrobial resistance. It is difficult to treat bacterial infection due to bacteria’s ability to develop resistance against antimicrobial agents. Antimicrobial agents are categorized according to their mechanism of action, i.e., interference with cell wall synthesis, DNA and RNA synthesis, lysis of the bacterial membrane, inhibition of protein synthesis, inhibition of metabolic pathways, etc. Bacteria may become resistant by antibiotic inactivation, target modification, efflux pump and plasmidic efflux. Currently, the clinically available treatment is not effective against the antibiotic resistance developed by some bacterial species. However, plant-based antimicrobials have immense potential to combat bacterial, fungal, protozoal and viral diseases without any known side effects. Such plant metabolites include quinines, alkaloids, lectins, polypeptides, flavones, flavonoids, flavonols, coumarin, terpenoids, essential oils and tannins. The present review focuses on antibiotic resistance, the resistance mechanism in bacteria against antibiotics and the role of plant-active secondary metabolites against microorganisms, which might be useful as an alternative and effective strategy to break the resistance among microbes. PMID:28394295

  9. Fate of Antibiotic Resistant Bacteria and Genes during Wastewater Chlorination: Implication for Antibiotic Resistance Control

    PubMed Central

    Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

    2015-01-01

    This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L). The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L). By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L). However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination. PMID:25738838

  10. A Decade-Long Commitment to Antimicrobial Resistance Surveillance in Portugal

    PubMed Central

    Marinho, Catarina M.; Santos, Tiago; Gonçalves, Alexandre; Poeta, Patrícia; Igrejas, Gilberto

    2016-01-01

    Antimicrobial resistance (AMR) is a worldwide problem with serious health and economic repercussions. Since the 1940s, underuse, overuse, and misuse of antibiotics have had a significant environmental downside. Large amounts of antibiotics not fully metabolized after use in human and veterinary medicine, and other applications, are annually released into the environment. The result has been the development and dissemination of antibiotic-resistant bacteria due to many years of selective pressure. Surveillance of AMR provides important information that helps in monitoring and understanding how resistance mechanisms develop and disseminate within different environments. Surveillance data is needed to inform clinical therapy decisions, to guide policy proposals, and to assess the impact of action plans to fight AMR. The Functional Genomics and Proteomics Unit, based at the University of Trás-os-Montes and Alto Douro in Vila Real, Portugal, has recently completed 10 years of research surveying AMR in bacteria, mainly commensal indicator bacteria such as enterococci and Escherichia coli from the microbiota of different animals. Samples from more than 75 different sources have been accessed, from humans to food-producing animals, pets, and wild animals. The typical microbiological workflow involved phenotypic studies followed by molecular approaches. Throughout the decade, 4,017 samples were collected and over 5,000 bacterial isolates obtained. High levels of AMR to several antimicrobial classes have been reported, including to β-lactams, glycopeptides, tetracyclines, aminoglycosides, sulphonamides, and quinolones. Multi-resistant strains, some relevant to human and veterinary medicine like extended-spectrum β-lactamase-producing E. coli and vancomycin-resistant enterococci, have been repeatedly isolated even in non-synanthropic animal species. Of particular relevance are reports of AMR bacteria in wildlife from natural reserves and endangered species. Future work

  11. Genotypic and Phenotypic Characterization of Antimicrobial-Resistant Escherichia coli from Farm-Raised Diarrheic Sika Deer in Northeastern China

    PubMed Central

    Li, Rui; He, Liang; Hao, Lili; Wang, Qi; Zhou, Yu; Jiang, Hongchen

    2013-01-01

    In China, overuse and/or abuse of antimicrobials are common in stockbreeding, which possess high risks of antimicrobial-resistant contaminations. The serogroups, major virulence genes, and antimicrobial resistant patterns of the antimicrobial-resistant Escherichia coli (E. coli) were investigated in the feces of diarrheic farm-raised sika deer from 50 farms in three Northeastern provinces of China. A total of 220 E. coli isolates were obtained and characterized. Twenty-eight O serogroups were identified from the obtained E. coli isolates with O2, O26, O128, O142 and O154 being dominant. Nearly all the isolates were resistant to at least four of the tested antimicrobials. More than 90% of the E. coli isolates carried at least one of the tested virulence genes. About 85% of the E. coli isolates carried one or more antimicrobial-resistant genes responsible for resistant phenotypes of sulfonamides, streptomycin/spectionomycin or tetracycline. The antimicrobial resistant level and pathogenic group occurrences of the obtained E. coli isolates were higher than that of livestock and wild animals reported in some developed countries. Thus, the fecal-carrying antimicrobial-resistant E. coli from the farm-raised sika deer is potentially a significant contamination source for freshwater systems and food chain, and may pose great health risks for human and animals in Northeastern China. PMID:24039919

  12. Screening of the Antimicrobial Activity against Drug Resistant Bacteria of Photorhabdus and Xenorhabdus Associated with Entomopathogenic Nematodes from Mae Wong National Park, Thailand

    PubMed Central

    Muangpat, Paramaporn; Yooyangket, Temsiri; Fukruksa, Chamaiporn; Suwannaroj, Manawat; Yimthin, Thatcha; Sitthisak, Sutthirat; Chantratita, Narisara; Vitta, Apichat; Tobias, Nicholas J.; Bode, Helge B.; Thanwisai, Aunchalee

    2017-01-01

    Photorhabdus and Xenorhabdus are symbiotic with entomopathogenic nematodes (EPNs) of the genera Heterorhabditis and Steinernema, respectively. These bacteria produce several secondary metabolites including antimicrobial compounds. The objectives of this study were to isolate and identify EPNs and their symbiotic bacteria from Mae Wong National Park, Thailand and to evaluate the antibacterial activities of symbiont extracts against drug resistant bacteria. A total of 550 soil samples from 110 sites were collected between August 2014 and July 2015. A total of EPN isolates were obtained through baiting and White trap methods, which yielded 21 Heterorhabditis and 3 Steinernema isolates. Based on molecular identification and phylogenetic analysis, the most common species found in the present study was P. luminescens subsp. akhurstii associated with H. indica. Notably, two species of EPNs, H. zealandica and S. kushidai, and two species of symbiotic bacteria, X. japonica and P. temperata subsp. temperata represented new recorded organisms in Thailand. Furthermore, the association between P. temperata subsp. temperata and H. zealandica has not previously been reported worldwide. Disk diffusion, minimal inhibitory concentration, and minimal bactericidal concentration analyses demonstrated that the crude compound extracted by ethyl acetate from P. temperata subsp. temperata could inhibit the growth of up to 10 strains of drug resistant bacteria. Based on HPLC-MS analysis, compound classes in bacterial extracts were identified as GameXPeptide, xenoamicin, xenocoumacin, mevalagmapeptide phurealipids derivatives, and isopropylstilbene. Together, the results of this study provide evidence for the diversity of EPNs and their symbiotic bacteria in Mae Wong National Park, Thailand and demonstrate their novel associations. These findings also provide an important foundation for further research regarding the antimicrobial activity of Photorhabdus bacteria. PMID:28702004

  13. Coping with antibiotic resistance: combining nanoparticles with antibiotics and other antimicrobial agents.

    PubMed

    Allahverdiyev, Adil M; Kon, Kateryna Volodymyrivna; Abamor, Emrah Sefik; Bagirova, Malahat; Rafailovich, Miriam

    2011-11-01

    The worldwide escalation of bacterial resistance to conventional medical antibiotics is a serious concern for modern medicine. High prevalence of multidrug-resistant bacteria among bacteria-based infections decreases effectiveness of current treatments and causes thousands of deaths. New improvements in present methods and novel strategies are urgently needed to cope with this problem. Owing to their antibacterial activities, metallic nanoparticles represent an effective solution for overcoming bacterial resistance. However, metallic nanoparticles are toxic, which causes restrictions in their use. Recent studies have shown that combining nanoparticles with antibiotics not only reduces the toxicity of both agents towards human cells by decreasing the requirement for high dosages but also enhances their bactericidal properties. Combining antibiotics with nanoparticles also restores their ability to destroy bacteria that have acquired resistance to them. Furthermore, nanoparticles tagged with antibiotics have been shown to increase the concentration of antibiotics at the site of bacterium-antibiotic interaction, and to facilitate binding of antibiotics to bacteria. Likewise, combining nanoparticles with antimicrobial peptides and essential oils generates genuine synergy against bacterial resistance. In this article, we aim to summarize recent studies on interactions between nanoparticles and antibiotics, as well as other antibacterial agents to formulate new prospects for future studies. Based on the promising data that demonstrated the synergistic effects of antimicrobial agents with nanoparticles, we believe that this combination is a potential candidate for more research into treatments for antibiotic-resistant bacteria.

  14. Quantitative Risk Assessment of Antimicrobial-Resistant Foodborne Infections in Humans Due to Recombinant Bovine Somatotropin Usage in Dairy Cows.

    PubMed

    Singer, Randall S; Ruegg, Pamela L; Bauman, Dale E

    2017-07-01

    Recombinant bovine somatotropin (rbST) is a production-enhancing technology that allows the dairy industry to produce milk more efficiently. Concern has been raised that cows supplemented with rbST are at an increased risk of developing clinical mastitis, which would potentially increase the use of antimicrobial agents and increase human illnesses associated with antimicrobial-resistant bacterial pathogens delivered through the dairy beef supply. The purpose of this study was to conduct a quantitative risk assessment to estimate the potential increased risk of human infection with antimicrobial-resistant bacteria and subsequent adverse health outcomes as a result of rbST usage in dairy cattle. The quantitative risk assessment included the following steps: (i) release of antimicrobial-resistant organisms from the farm, (ii) exposure of humans via consumption of contaminated beef products, and (iii) consequence of the antimicrobial-resistant infection. The model focused on ceftiofur (parenteral and intramammary) and oxytetracycline (parenteral) treatment of clinical mastitis in dairy cattle and tracked the bacteria Campylobacter spp., Salmonella enterica subsp. enterica, and Escherichia coli in the gastrointestinal tract of the cow. Parameter estimates were developed to be maximum risk to overestimate the risk to humans. The excess number of cows in the U.S. dairy herd that were predicted to carry resistant bacteria at slaughter due to rbST administration was negligible. The total number of excess human illnesses caused by resistant bacteria due to rbST administration was also predicted to be negligible with all risks considerably less than one event per 1 billion people at risk per year for all bacteria. The results indicate a high probability that the use of rbST according to label instructions presents a negligible risk for increasing the number of human illnesses and subsequent adverse outcomes associated with antimicrobial-resistant Campylobacter, Salmonella, or

  15. Occurrence of fecal coliform bacteria in selected streams in Wyoming, 1990-99

    USGS Publications Warehouse

    Clark, Melanie L.; Norris, Jodi R.

    2000-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Wyoming Department of Environmental Quality (WDEQ), is collecting water samples for analysis of fecal coliform bacteria at 18 stream sites as part of a statewide network. Contamination by bacteria of fecal origin in streams where contact recreation is a designated water use is a concern because of potential public-health risk from the presence of enteric pathogens. Fecal coliform concentrations are temporally and spatially variable in Wyoming streams-concentrations ranged from less than 1 to 45,000 colonies per 100 milliliters of water during 1990-99. Fecal coliform concentrations were less than the water-quality criterion of 400 colonies per 100 milliliters in 83 percent of the samples, indicating fecal coliform contamination is not a widespread problem in these Wyoming streams. However, 14 of the 18 monitoring sites had at least one sample in which the fecal coliform concentration exceeded 400 colonies per 100 milliliters at some time during the 10-year period. Fecal coliform concentrations generally are higher during April through September than during October through March. The higher concentrations coincide with the time period when the public-health risk is higher because summer months are when contact recreation use is more likely occurring. Fecal coliform concentrations were positively correlated with discharge and stream temperature and generally were negatively correlated with pH, specific conductance, and dissolved oxygen.

  16. Occurrence of fecal-indicator bacteria and protocols for identification of fecal-contamination sources in selected reaches of the West Branch Brandywine Creek, Chester County, Pennsylvania

    USGS Publications Warehouse

    Cinotto, Peter J.

    2005-01-01

    The presence of fecal-indicator bacteria indicates the potential presence of pathogens originating from the fecal matter of warm-blooded animals. These pathogens are responsible for numerous human diseases ranging from common diarrhea to meningitis and polio. The detection of fecal-indicator bacteria and interpretation of the resultant data are, therefore, of great importance to water-resource managers. Current (2005) techniques used to assess fecal contamination within the fluvial environment primarily assess samples collected from the water column, either as grab samples or as depth- and (or) width-integrated samples. However, current research indicates approximately 99 percent of all bacteria within nature exist as attached, or sessile, bacteria. Because of this condition, most current techniques for the detection of fecal contamination, which utilize bacteria, assess only about 1 percent of the total bacteria within the fluvial system and are, therefore, problematic. Evaluation of the environmental factors affecting the occurrence and distribution of bacteria within the fluvial system, as well as the evaluation and modification of alternative approaches that effectively quantify the larger population of sessile bacteria within fluvial sediments, will present water-resource managers with more effective tools to assess, prevent, and (or) eliminate sources of fecal contamination within pristine and impaired watersheds. Two stream reaches on the West Branch Brandywine Creek in the Coatesville, Pa., region were studied between September 2002 and August 2003. The effects of sediment particle size, climatic conditions, aquatic growth, environmental chemistry, impervious surfaces, sediment and soil filtration, and dams on observed bacteria concentrations were evaluated. Alternative approaches were assessed to better detect geographic sources of fecal contamination including the use of turbidity as a surrogate for bacteria, the modification and implementation of sandbag

  17. Antimicrobial resistance in zoonotic nontyphoidal Salmonella: an alarming trend?

    PubMed

    Michael, G B; Schwarz, S

    2016-12-01

    Zoonotic bacteria of the genus Salmonella have acquired various antimicrobial resistance properties over the years. The corresponding resistance genes are commonly located on plasmids, transposons, gene cassettes, or variants of the Salmonella Genomic Islands SGI1 and SGI2. Human infections by nontyphoidal Salmonella isolates mainly result from ingestion of contaminated food. The two predominantly found Salmonella enterica subsp. enterica serovars in the USA and in Europe are S. Enteritidis and S. Typhimurium. Many other nontyphoidal Salmonella serovars have been implicated in foodborne Salmonella outbreaks. Summary reports of the antimicrobial susceptibility patterns of nontyphoidal Salmonella isolates over time suggest a moderate to low level of antimicrobial resistance and multidrug-resistance. However, serovar-specific analyses showed in part a steady state, a continuous decline, or a recent increase in resistance to certain antimicrobial agents. Resistance to critically important antimicrobial agents, e.g. third-generation cephalosporins and (fluoro)quinolones is part of many monitoring programmes and the corresponding results confirm that extended-spectrum β-lactamases are still rarely found in nontyphoidal Salmonella serovars, whereas resistance to (fluoro)quinolones is prevalent at variable frequencies among different serovars from humans and animals in different countries. Although it is likely that nontyphoidal Salmonella isolates from animals represent a reservoir for resistance determinants, it is mostly unknown where and when Salmonella isolates acquired resistance properties and which exchange processes have happened since then. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  18. Temperate and lytic bacteriophages programmed to sensitize and kill antibiotic-resistant bacteria

    PubMed Central

    Yosef, Ido; Manor, Miriam; Kiro, Ruth

    2015-01-01

    The increasing threat of pathogen resistance to antibiotics requires the development of novel antimicrobial strategies. Here we present a proof of concept for a genetic strategy that aims to sensitize bacteria to antibiotics and selectively kill antibiotic-resistant bacteria. We use temperate phages to deliver a functional clustered regularly interspaced short palindromic repeats (CRISPR)–CRISPR-associated (Cas) system into the genome of antibiotic-resistant bacteria. The delivered CRISPR-Cas system destroys both antibiotic resistance-conferring plasmids and genetically modified lytic phages. This linkage between antibiotic sensitization and protection from lytic phages is a key feature of the strategy. It allows programming of lytic phages to kill only antibiotic-resistant bacteria while protecting antibiotic-sensitized bacteria. Phages designed according to this strategy may be used on hospital surfaces and hand sanitizers to facilitate replacement of antibiotic-resistant pathogens with sensitive ones. PMID:26060300

  19. Temperate and lytic bacteriophages programmed to sensitize and kill antibiotic-resistant bacteria.

    PubMed

    Yosef, Ido; Manor, Miriam; Kiro, Ruth; Qimron, Udi

    2015-06-09

    The increasing threat of pathogen resistance to antibiotics requires the development of novel antimicrobial strategies. Here we present a proof of concept for a genetic strategy that aims to sensitize bacteria to antibiotics and selectively kill antibiotic-resistant bacteria. We use temperate phages to deliver a functional clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) system into the genome of antibiotic-resistant bacteria. The delivered CRISPR-Cas system destroys both antibiotic resistance-conferring plasmids and genetically modified lytic phages. This linkage between antibiotic sensitization and protection from lytic phages is a key feature of the strategy. It allows programming of lytic phages to kill only antibiotic-resistant bacteria while protecting antibiotic-sensitized bacteria. Phages designed according to this strategy may be used on hospital surfaces and hand sanitizers to facilitate replacement of antibiotic-resistant pathogens with sensitive ones.

  20. Antimicrobial Activity of Cationic Antimicrobial Peptides against Gram-Positives: Current Progress Made in Understanding the Mode of Action and the Response of Bacteria

    PubMed Central

    Omardien, Soraya; Brul, Stanley; Zaat, Sebastian A. J.

    2016-01-01

    Antimicrobial peptides (AMPs) have been proposed as a novel class of antimicrobials that could aid the fight against antibiotic resistant bacteria. The mode of action of AMPs as acting on the bacterial cytoplasmic membrane has often been presented as an enigma and there are doubts whether the membrane is the sole target of AMPs. Progress has been made in clarifying the possible targets of these peptides, which is reported in this review with as focus gram-positive vegetative cells and spores. Numerical estimates are discussed to evaluate the possibility that targets, other than the membrane, could play a role in susceptibility to AMPs. Concerns about possible resistance that bacteria might develop to AMPs are addressed. Proteomics, transcriptomics, and other molecular techniques are reviewed in the context of explaining the response of bacteria to the presence of AMPs and to predict what resistance strategies might be. Emergent mechanisms are cell envelope stress responses as well as enzymes able to degrade and/or specifically bind (and thus inactivate) AMPs. Further studies are needed to address the broadness of the AMP resistance and stress responses observed. PMID:27790614

  1. Distribution and variability of fecal-indicator bacteria in Scioto and Olentangy rivers in the Columbus, Ohio, area

    USGS Publications Warehouse

    Myers, Donna N.

    1992-01-01

    This report presents the results of a study by the U.S. Geological Survey, in cooperation with the City of Columbus, Ohio, to determine the distribution and variability of fecal-indicator bacteria in Scioto and Olentangy Rivers. Fecal-indicator bacteria are among the contaminants of concern to recreational users of these rivers in the Columbus area. Samples were collected to be analyzed for fecal-coliform and Escherichia coli (E. coli) bacteria and selected water-quality constituents and physical properties at 10 sites-- 4 on the Olentangy River and 6 on the Scioto River during the recreational seasons in 1987, 1988, and 1989. Measurements of streamflow also were made at these sites at various frequencies during base flow and runoff. The concentrations of fecal-coliform and E. coli bacteria in the Scioto and Olentangy Rivers spanned a range of five orders of magnitude, from less than 20 to greater than 2,000,000 col/100 mL (colonies per 100 milliliters). In addition, the concentrations of fecal coliform and E. coli bacteria are well correlated (r=0.97) in the study area. At times, relatively high concentrations, for fecal-indicator bacteria (concentrations greater than 51,000 col/100 mL for fecal-coliform and E. coli ) were found in Olentangy River at Woody Hayes Drive and at Goodale Street, and in Scioto River at Greenlawn Avenue and at Columbus. Intermediate concentrations of fecal-indicator bacteria (from 5,100 to 50,000 col/100 mL for fecal coliform and (from 510 to 50,000 col/100 mL for E. coli ) were found in Scioto River at Town Street and below O'Shaughnessy Dam near Dublin, Ohio, and in Olentangy River at Henderson Road. The lowest (median) concentrations of fecal-indicator bacteria (from 20 to 5,000 col/100 mL for fecal coliform and from 20 to 500 col/100 mL for E. coli ) were found at Olentangy River near Worthington, Ohio, Scioto River at Dublin Road Water Treatment Plant and below Griggs Reservoir. Fecal-coliform concentrations exceeded the geometric

  2. Distribution of species and antimicrobial resistance among enterococci isolated from the fecal microbiota of captive blue-fronted parrot (Amazona aestiva) in Rio de Janeiro, Brazil.

    PubMed

    Freitas, Andréa de Andrade Rangel de; Faria, Adriana Rocha; Pinto, Tatiana de Castro Abreu; Merquior, Vânia Lúcia Carreira; Neves, Daniel Marchesi; Costa, Rodrigo de Cerqueira da; Teixeira, Lúcia Martins

    2018-02-15

    Enterococcal strains recovered from fecal samples of captive blue-fronted parrots (Amazona aestiva) assisted at two wild animal screening centers in Rio de Janeiro, Brazil, were identified as Enterococcus hirae (the predominant species; 75.3%), followed by Enterococcus faecalis (17.3%), Enterococcus casseliflavus (4.8%), Enterococcus gallinarum (1.7%), and Enterococcus hermanniensis (0.9%). All strains were susceptible to linezolid and teicoplanin. Rates of nonsusceptibility (including resistant and intermediate categories) to other 16 antimicrobials tested varied from 69.3% to 0.4%, A considerable proportion (48.0%) of the strains was multidrug-resistant and diverse genetic determinants associated with antimicrobial resistance were identified. Tetracycline-resistant strains carried the tet(M) and/or tet(L) genes. Macrolides resistance was associated with the erm(B), erm(A) and mefA genes, while 43.2% of the isolates were negative for the investigated genes. High-level resistance to gentamicin associated with the aac(6')-le-aph(2″)-la gene was detected in one E. faecalis strain. The two strains presenting high-level resistance to streptomycin were negative for the ant(6')-Ia, ant(3')-Ia, ant(9')-Ia and ant(9')-Ib genes. The vat(D) gene was found in all the 47 quinupristin/dalfopristin resistant strains identified as non-E. faecalis. Analysis of PFGE profiles of E. hirae strains after restriction with SmaI demonstrated the occurrence of five clonal groups. The predominant E. hirae clone was distributed among birds in the two institutions, suggesting that this clone was well adapted to the host and environments investigated. The four clonal groups identified among E. faecalis were composed by small numbers of strains and, generally, restricted to birds in the same sector. The occurrence of enterococcal strains exhibiting antimicrobial resistance traits and carrying genetic determinants that represent potential threats to the health of both humans and animals, in

  3. Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik's Cube of Clinical Microbiology?

    PubMed

    Gajdács, Márió; Spengler, Gabriella; Urbán, Edit

    2017-11-07

    Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria.

  4. Antibiotic resistance monitoring: the Spanish programme. The VAV Network. Red de Vigilancia de Resistencias Antibióticas en Bacterias de Origen Veterinario.

    PubMed

    Moreno, M A; Domínguez, L; Teshager, T; Herrero, I A; Porrero, M C

    2000-05-01

    Antimicrobial resistance is a problem in modern public health and antimicrobial use and especially misuse, the most important selecting force for bacterial antibiotic resistance. As this resistance must be monitored we have designed the Spanish network 'Red de Vigilancia de Resistencias Antibióticas en Bacterias de Origen Veterinario'. This network covers the three critical points of veterinary responsibility, bacteria from sick animals, bacteria from healthy animals and bacteria from food animals. Key bacteria, antimicrobials and animal species have been defined for each of these groups along with laboratory methods for testing antimicrobial susceptibility and for data analysis and reporting. Surveillance of sick animals was first implemented using Escherichia coli as the sentinel bacterium. Surveillance of E. coli and Enterococcus faecium from healthy pigs was implemented in 1998. In July 1999, data collection on Salmonella spp. was initiated in poultry slaughterhouses. Additionally, the prevalence of vancomycin resistant E. faecium was also monitored. This network has specific topics of interest related to methods of determining resistance, analysis and reporting of data, methods of use for veterinary practitioners and collaboration with public health authorities.

  5. Role of Nutrients and Phyto-compounds in the Modulation of Antimicrobial Resistance.

    PubMed

    Harakeh, Steve; Khan, Imran; Almasaudi, Saad B; Azhar, Esam I; Al-Jaouni, Soad; Niedzweicki, Aleksandra

    2017-01-01

    Antimicrobial resistance is quickly spreading and has become a major public health problem worldwide. If this issue is not resolved, it may cause a shift back to the pre-antibiotics era and infectious disease will again be a serious problem, especially in developing countries. Since the discovery of antibiotics, bacterial resistance has emerged, enabling certain bacteria to withstand antibiotic action. The emergence of antibiotic resistance is fueled by excessive and improper use of antimicrobial agents, especially in developing countries. For this reason, alternatives to or modifications of current treatment methods have been sought. The aim of this review is to highlight the possible synergies of various agents that can augment antibiotic activities. A structured literature search was conducted using only papers that have been published in PubMed with the focus on the agents that are likely to modulate antimicrobial resistance. In this review, data was retrieved from the literature regarding the possible synergies that exist between commercially available antimicrobial drugs with agents of interest. The papers included were summarized and analyzed, critiqued and compared for their contents using a conceptual frame-work. In total, one hundred and twenty six papers were reviewed. The number of papers that dealt with the different topics included are as follows (): emergence of antimicrobial resistance (22), bioactive phyto-compounds (36) (phytobiologics, and phytochemicals), Antioxidants (40) (N-acetylcysteine, Ambroxol, Ascorbic acid, Glutathione and vitamin E), Peptide synergies (14) (Synthetic cationic α-helical AMPs, CopA3, Alafosfalin, PMAP-36, Phosphonopeptide L-norvalyl-L-1-aminoethylphosphonic acid and norcardicin-A), nano-antibiotics (10), drug-compound interactions (4).This review addressed the new strategies using the above compounds in the modulation of antimicrobial resistance to avoid issues related to resistance of bacteria to antibiotics. The

  6. Antimicrobial resistance among Campylobacter strains, United States, 1997-2001.

    PubMed

    Gupta, Amita; Nelson, Jennifer M; Barrett, Timothy J; Tauxe, Robert V; Rossiter, Shannon P; Friedman, Cindy R; Joyce, Kevin W; Smith, Kirk E; Jones, Timothy F; Hawkins, Marguerite A; Shiferaw, Belershacew; Beebe, James L; Vugia, Duc J; Rabatsky-Ehr, Terry; Benson, James A; Root, Timothy P; Angulo, Frederick J

    2004-06-01

    We summarize antimicrobial resistance surveillance data in human and chicken isolates of Campylobacter. Isolates were from a sentinel county study from 1989 through 1990 and from nine state health departments participating in National Antimicrobial Resistance Monitoring System for enteric bacteria (NARMS) from 1997 through 2001. None of the 297 C. jejuni or C. coli isolates tested from 1989 through 1990 was ciprofloxacin-resistant. From 1997 through 2001, a total of 1,553 human Campylobacter isolates were characterized: 1,471 (95%) were C. jejuni, 63 (4%) were C. coli, and 19 (1%) were other Campylobacter species. The prevalence of ciprofloxacin-resistant Campylobacter was 13% (28 of 217) in 1997 and 19% (75 of 384) in 2001; erythromycin resistance was 2% (4 of 217) in 1997 and 2% (8 of 384) in 2001. Ciprofloxacin-resistant Campylobacter was isolated from 10% of 180 chicken products purchased from grocery stores in three states in 1999. Ciprofloxacin resistance has emerged among Campylobacter since 1990 and has increased in prevalence since 1997.

  7. Agriculture and food animals as a source of antimicrobial-resistant bacteria

    PubMed Central

    Economou, Vangelis; Gousia, Panagiota

    2015-01-01

    One of the major breakthroughs in the history of medicine is undoubtedly the discovery of antibiotics. Their use in animal husbandry and veterinary medicine has resulted in healthier and more productive farm animals, ensuring the welfare and health of both animals and humans. Unfortunately, from the first use of penicillin, the resistance countdown started to tick. Nowadays, the infections caused by antibiotic-resistant bacteria are increasing, and resistance to antibiotics is probably the major public health problem. Antibiotic use in farm animals has been criticized for contributing to the emergence of resistance. The use and misuse of antibiotics in farm animal settings as growth promoters or as nonspecific means of infection prevention and treatment has boosted antibiotic consumption and resistance among bacteria in the animal habitat. This reservoir of resistance can be transmitted directly or indirectly to humans through food consumption and direct or indirect contact. Resistant bacteria can cause serious health effects directly or via the transmission of the antibiotic resistance traits to pathogens, causing illnesses that are difficult to treat and that therefore have higher morbidity and mortality rates. In addition, the selection and proliferation of antibiotic-resistant strains can be disseminated to the environment via animal waste, enhancing the resistance reservoir that exists in the environmental microbiome. In this review, an effort is made to highlight the various factors that contribute to the emergence of antibiotic resistance in farm animals and to provide some insights into possible solutions to this major health issue. PMID:25878509

  8. Antibiotic-resistant bacteria in the Hudson River Estuary linked to wet weather sewage contamination.

    PubMed

    Young, Suzanne; Juhl, Andrew; O'Mullan, Gregory D

    2013-06-01

    Heterotrophic bacteria resistant to tetracycline and ampicillin were assessed in waterways of the New York City metropolitan area using culture-dependent approaches and 16S rRNA gene sequence analysis of resultant isolates. Resistant microbes were detected at all 10 sampling sites in monthly research cruises on the lower Hudson River Estuary (HRE), with highest concentrations detected at nearshore sites. Higher frequency sampling was conducted in Flushing Bay, to enumerate resistant microbes under both dry and wet weather conditions. Concentrations of ampicillin- and tetracycline-resistant bacteria, in paired samples, were positively correlated with one another and increased following precipitation. Counts of the fecal indicator, Enterococcus, were positively correlated with levels of resistant bacteria, suggesting a shared sewage-associated source. Analysis of 16S rRNA from isolates identified a phylogenetically diverse group of resistant bacteria, including genera containing opportunistic pathogens. The occurrence of Enterobacteriaceae, a family of enteric bacteria, was found to be significantly higher in resistant isolates compared to total heterotrophic bacteria and increased following precipitation. This study is the first to document the widespread distribution of antibiotic-resistant bacteria in the HRE and to demonstrate clearly a link between the abundance of antibiotic-resistant bacteria and levels of sewage-associated bacteria in an estuary.

  9. Synergetic Antimicrobial Effects of Mixtures of Ethiopian Honeys and Ginger Powder Extracts on Standard and Resistant Clinical Bacteria Isolates

    PubMed Central

    Ewnetu, Yalemwork; Lemma, Wossenseged; Birhane, Nega

    2014-01-01

    Purpose. To evaluate antimicrobial effects of mixtures of Ethiopian honeys and ginger rhizome powder extracts on Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Staphylococcus aureus (MRSA), Escherichia coli (R), and Klebsiella pneumoniae (R). Methods. Agar diffusion and broth assays were performed to determine susceptibility of these standard and resistant clinical bacteria isolates using honey-ginger powder extract mixtures. Results. Honey-ginger powder extract mixtures produced the highest mean inhibition (25.62 mm ± 2.55) compared to the use of honeys (21.63 mm ± 3.30) or ginger extracts (19.23 mm ± 3.42) individually. The ranges of inhibitions produced by honey-ginger extract mixtures on susceptible test organisms (26–30 mm) and resistant strains (range: 19–27 mm) were higher compared to 7–22 mm and 0–14 mm by standard antibiotic discs. Minimum inhibitory concentrations (MIC) of mixture of honeys-ginger extracts were 6.25% (0.625 v/mL) on the susceptible bacteria compared to 75% for resistant clinical isolates. Minimum bactericidal concentration (MBC) of honey-ginger extracts was 12.5% (0.125 g/mL) for all the test organisms. Conclusion. The result of this study showed that honey-ginger powder extract mixtures have the potential to serve as cheap source of antibacterial agents especially for the drug resistant bacteria strains. PMID:24772182

  10. Fecal Microbiota Transplantation Inhibits Multidrug-Resistant Gut Pathogens: Preliminary Report Performed in an Immunocompromised Host.

    PubMed

    Biliński, Jarosław; Grzesiowski, Paweł; Muszyński, Jacek; Wróblewska, Marta; Mądry, Krzysztof; Robak, Katarzyna; Dzieciątkowski, Tomasz; Wiktor-Jedrzejczak, Wiesław; Basak, Grzegorz W

    2016-06-01

    Colonization of the gastrointestinal tract with multidrug-resistant (MDR) bacteria is a consequence of gut dysbiosis. We describe the successful utilization of fecal microbiota transplantation to inhibit Klebsiella pneumoniae MBL(+) and Escherichia coli ESBL(+) gut colonization in the immunocompromised host as a novel tool in the battle against MDR microorganisms. ClinicalTrials.gov identifier NCT02461199.

  11. [Antibiotic-resistant bacteria and new directions of antimicrobial chemotherapy].

    PubMed

    Tateda, Kazuhiro

    2012-05-01

    The emergence and spread of antibiotic-resistant organisms are becoming more and more serious and are a worldwide problem. Recent trends in new antibiotic-resistant organisms include multiple-drug resistant Pseudomonas aeruginosa (MDRP), MDR-Acinetobacter baumannii (MDR-AB) and New Deli metallo beta-lactamase-1 (NDM-1) -producing bacteria. Antibiotic combination therapy is an option to overcome these MDR organisms. A breakpoint checkerboard plate was created to measure antibiotic combination effects at breakpoint concentrations, making it possible to evaluate the synergy of antibiotic combination within 24 hours. In this article, recent topics regarding antibiotic-resistant organisms are briefly reviewed and the directions of antibiotic chemotherapy against these organisms are discussed.

  12. Changes in the equine fecal microbiota associated with the use of systemic antimicrobial drugs.

    PubMed

    Costa, Marcio C; Stämpfli, Henry R; Arroyo, Luis G; Allen-Vercoe, Emma; Gomes, Roberta G; Weese, J Scott

    2015-02-03

    The intestinal tract is a rich and complex environment and its microbiota has been shown to have an important role in health and disease in the host. Several factors can cause disruption of the normal intestinal microbiota, including antimicrobial therapy, which is an important cause of diarrhea in horses. This study aimed to characterize changes in the fecal bacterial populations of healthy horses associated with the administration of frequently used antimicrobial drugs. Twenty-four adult mares were assigned to receive procaine penicillin intramuscularly (IM), ceftiofur sodium IM, trimethoprim sulfadiazine (TMS) orally or to a control group. Treatment was given for 5 consecutive days and fecal samples were collected before drug administration (Day 1), at the end of treatment (Days 5), and on Days 14 and 30 of the trial. High throughput sequencing of the V4 region of the 16S rRNA gene was performed using an Illumina MiSeq sequencer. Significant changes of population structure and community membership were observed after the use of all drugs. TMS caused the most marked changes on fecal microbiota even at higher taxonomic levels including a significant decrease of richness and diversity. Those changes were mainly due to a drastic decrease of Verrucomicrobia, specifically the "5 genus incertae sedis". Changes in structure and membership caused by antimicrobial administration were specific for each drug and may be predictable. Twenty-five days after the end of treatment, bacterial profiles were more similar to pre-treatment patterns indicating a recovery from changes caused by antimicrobial administration, but differences were still evident, especially regarding community membership. The use of systemic antimicrobials leads to changes in the intestinal microbiota, with different and specific responses to different antimicrobials. All antimicrobials tested here had some impact on the microbiota, but TMS significantly reduced bacterial species richness and diversity and

  13. Antibacterial potential of phytochemicals alone or in combination with antimicrobials against fish pathogenic bacteria.

    PubMed

    Bandeira Junior, G; Sutili, F J; Gressler, L T; Ely, V L; Silveira, B P; Tasca, C; Reghelin, M; Matter, L B; Vargas, A P C; Baldisserotto, B

    2018-05-09

    This study investigated the antibacterial activity of five phytochemicals (carvacrol, citral, eugenol, linalool, and thymol) alone or in combination with florfenicol or oxytetracycline against bacteria isolated from silver catfish (Rhamdia quelen). We also analyzed the potential of these compounds to inhibit biofilm formation and hemolysis caused by the bacteria. Bacteria were tested with antimicrobials to calculate the multiple antibiotic resistance (MAR). The checkerboard assay was used to evaluate a putative synergy between five phytochemicals and antimicrobials against the strains isolated. The biofilm formation inhibition assay was performed with phytochemicals and antimicrobials, and the hemolysis inhibition assay was performed with the phytochemicals. Carvacrol, eugenol and thymol were the most effective phytochemicals. Three combinations (linalool with florfenicol or oxytetracycline against Aeromonas hydrophila and citral with oxytetracycline against Citrobacter freundii) demonstrated synergy in the checkerboard assay. All phytochemicals inhibited biofilm formation and hemolysis activity. The tested phytochemicals showed satisfactory activity against fish pathogenic bacteria. The phytochemicals did not present antagonistic interactions with the antimicrobials, allowing their combined use, which may contribute to a decrease in the use of conventional drugs and their residues in aquatic environment. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  14. Colistin Heteroresistance in Enterobacter cloacae Is Associated with Cross-Resistance to the Host Antimicrobial Lysozyme

    PubMed Central

    Napier, Brooke A.; Band, Victor

    2014-01-01

    Here, we describe the first identification of colistin-heteroresistant Enterobacter cloacae in the United States. Treatment of this isolate with colistin increased the frequency of the resistant subpopulation and induced cross-resistance to the host antimicrobial lysozyme. This is the first description of heteroresistance conferring cross-resistance to a host antimicrobial and suggests that clinical treatment with colistin may inadvertently select for bacteria that are resistant to components of the host innate immune system. PMID:24982068

  15. Bacteriophages Isolated from Chicken Meat and the Horizontal Transfer of Antimicrobial Resistance Genes

    PubMed Central

    Shousha, Amira; Awaiwanont, Nattakarn; Sofka, Dmitrij; Smulders, Frans J. M.; Paulsen, Peter; Szostak, Michael P.; Humphrey, Tom

    2015-01-01

    Antimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments. The transfer of antimicrobial resistance genes by phages could underlie the origin of resistant bacteria found in food. We show that chicken meat carries a number of phages capable of transferring antimicrobial resistance. Of 243 phages randomly isolated from chicken meat, about a quarter (24.7%) were able to transduce resistance to one or more of the five antimicrobials tested into Escherichia coli ATCC 13706 (DSM 12242). Resistance to kanamycin was transduced the most often, followed by that to chloramphenicol, with four phages transducing tetracycline resistance and three transducing ampicillin resistance. Phages able to transduce antimicrobial resistance were isolated from 44% of the samples of chicken meat that we tested. The statistically significant (P = 0.01) relationship between the presence of phages transducing kanamycin resistance and E. coli isolates resistant to this antibiotic suggests that transduction may be an important mechanism for transferring kanamycin resistance to E. coli. It appears that the transduction of resistance to certain antimicrobials, e.g., kanamycin, not only is widely distributed in E. coli isolates found on meat but also could represent a major mechanism for resistance transfer. The result is of high importance for animal and human health. PMID:25934615

  16. Antibiotic-resistant bacteria: prevalence in food and inactivation by food-compatible compounds and plant extracts.

    PubMed

    Friedman, Mendel

    2015-04-22

    Foodborne antibiotic-resistant pathogenic bacteria such as Campylobacter jejuni, Bacillus cereus, Clostridium perfringens, Escherichia coli, Salmonella enterica, Staphylococcus aureus, Vibrio cholerae, and Vibrio parahemolyticus can adversely affect animal and human health, but a better understanding of the factors involved in their pathogenesis is needed. To help meet this need, this overview surveys and interprets much of our current knowledge of antibiotic (multidrug)-resistant bacteria in the food chain and the implications for microbial food safety and animal and human health. Topics covered include the origin and prevalence of resistant bacteria in the food chain (dairy, meat, poultry, seafood, and herbal products, produce, and eggs), their inactivation by different classes of compounds and plant extracts and by the use of chlorine and physicochemical methods (heat, UV light, pulsed electric fields, and high pressure), the synergistic antimicrobial effects of combinations of natural antimicrobials with medicinal antibiotics, and mechanisms of antimicrobial activities and resistant effects. Possible areas for future research are suggested. Plant-derived and other safe natural antimicrobial compounds have the potential to control the prevalence of both susceptible and resistant pathogens in various environments. The collated information and suggested research will hopefully contribute to a better understanding of approaches that could be used to minimize the presence of resistant pathogens in animal feed and human food, thus reducing adverse effects, improving microbial food safety, and helping to prevent or treat animal and human infections.

  17. The antimicrobial resistance monitoring and research (ARMoR) program: the US Department of Defense response to escalating antimicrobial resistance.

    PubMed

    Lesho, Emil P; Waterman, Paige E; Chukwuma, Uzo; McAuliffe, Kathryn; Neumann, Charlotte; Julius, Michael D; Crouch, Helen; Chandrasekera, Ruvani; English, Judith F; Clifford, Robert J; Kester, Kent E

    2014-08-01

    Responding to escalating antimicrobial resistance (AMR), the US Department of Defense implemented an enterprise-wide collaboration, the Antimicrobial Resistance Monitoring and Research Program, to aid in infection prevention and control. It consists of a network of epidemiologists, bioinformaticists, microbiology researchers, policy makers, hospital-based infection preventionists, and healthcare providers who collaborate to collect relevant AMR data, conduct centralized molecular characterization, and use AMR characterization feedback to implement appropriate infection prevention and control measures and influence policy. A particularly concerning type of AMR, carbapenem-resistant Enterobacteriaceae, significantly declined after the program was launched. Similarly, there have been no further reports or outbreaks of another concerning type of AMR, colistin resistance in Acinetobacter, in the Department of Defense since the program was initiated. However, bacteria containing AMR-encoding genes are increasing. To update program stakeholders and other healthcare systems facing such challenges, we describe the processes and impact of the program. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  18. Antimicrobial resistance determinant microarray for analysis of multi-drug resistant isolates

    NASA Astrophysics Data System (ADS)

    Taitt, Chris Rowe; Leski, Tomasz; Stenger, David; Vora, Gary J.; House, Brent; Nicklasson, Matilda; Pimentel, Guillermo; Zurawski, Daniel V.; Kirkup, Benjamin C.; Craft, David; Waterman, Paige E.; Lesho, Emil P.; Bangurae, Umaru; Ansumana, Rashid

    2012-06-01

    The prevalence of multidrug-resistant infections in personnel wounded in Iraq and Afghanistan has made it challenging for physicians to choose effective therapeutics in a timely fashion. To address the challenge of identifying the potential for drug resistance, we have developed the Antimicrobial Resistance Determinant Microarray (ARDM) to provide DNAbased analysis for over 250 resistance genes covering 12 classes of antibiotics. Over 70 drug-resistant bacteria from different geographic regions have been analyzed on ARDM, with significant differences in patterns of resistance identified: genes for resistance to sulfonamides, trimethoprim, chloramphenicol, rifampin, and macrolide-lincosamidesulfonamide drugs were more frequently identified in isolates from sources in Iraq/Afghanistan. Of particular concern was the presence of genes responsible for resistance to many of the last-resort antibiotics used to treat war traumaassociated infections.

  19. Canadian integrated program for antimicrobial resistance surveillance: Retail food highlights, 2003–2012

    PubMed Central

    Avery, BP; Parmley, EJ; Reid-Smith, RJ; Daignault, D; Finley, RL; Irwin, RJ

    2014-01-01

    Background The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) is a collaborative, integrated program designed to track antimicrobial resistance (AMR) among enteric bacteria isolated from various livestock commodities along the food-producing continuum (“farm to fork”) and in humans. Objective To provide a summary of the prevalence and trends in AMR among select bacteria isolated from raw, fresh chicken, pork, and beef in 2012 at the retail food level and to link these data with other findings from CIPARS. Methods Meat samples were collected from randomly selected geographic areas across Canada weighted by population for subsequent isolation of bacteria and interpretation of the associated AMR profiles. Salmonella, Campylobacter and generic Escherichia coli (E. coli) were tested in chicken, and E. coli was tested in beef and pork. Data were analyzed for 2012 and temporal and regional trends were examined between 2003 and 2012 by province/region. Results Overall, resistance levels to Salmonella in retail chicken varied widely by region and year. For example, ceftiofur resistance to Salmonella in retail chicken was significantly lower in 2012 than in 2004 in Ontario and in Québec; however, among all regions sampled, resistance was significantly higher in 2012 compared to 2006. Across all regions sampled, resistance to Campylobacter in retail chicken was relatively low in 2012 (<16%) with the exception of tetracycline resistance. In 2012, ciprofloxacin resistance to Campylobacter in chicken declined in British Columbia but significantly increased in Ontario, compared to 2011. In 2012, β-lactam resistance to E. coli in retail beef remained low (≤1%) and was also relatively low comparable to previous years in pork. Conclusion In Canada, as is the case worldwide, there is evidence of resistance to medically important antimicrobials among bacteria from retail meats. Resistance among organisms isolated from poultry, beef, and pork at

  20. Occurrence and antimicrobial drug susceptibility patterns of commensal and diarrheagenic Escherichia coli in fecal microbiota from children with and without acute diarrhea.

    PubMed

    Garcia, Patrícia G; Silva, Vânia L; Diniz, Cláudio G

    2011-02-01

    Acute diarrhea is a public health problem and an important cause of morbidity and mortality, especially in developing countries. The etiology is varied, and the diarrheagenic Escherichia coli pathotypes are among the most important. Our objectives were to determine the occurrence of commensal and diarrheagenic E. coli strains in fecal samples from children under five years old and their drug susceptibility patterns. E. coli were isolated from 141 fresh fecal samples; 84 were obtained from clinically injured donors with acute diarrhea (AD) and 57 from clinically healthy donors without diarrhea (WD). Presumptive phenotypic species identification was carried out and confirmed by amplification of specific 16S ribosomal RNA encoding DNA. Multiplex PCR was performed to characterize the diarrheagenic E. coli strains. Drug susceptibility patterns were determined by the disc-diffusion method. In total, 220 strains were recovered from the fecal specimens (61.8% from AD and 38.2% from WD). Diarrheagenic E. coli was identified at a rate of 36.8% (n=50) in diarrheic feces and 29.8% (n=25) in non-diarrheic feces. Enteroaggregative E. coli was the most frequently identified pathotype in the AD group (16.2%) and the only pathotype identified in the WD group (30.9%). Enteropathogenic E. coli was the second most isolated pathotype (10.3%), followed by Shiga toxin-producing E. coli (7.4%) and enterotoxigenic E. coli (2.9%). No enteroinvasive E. coli strains were recovered. The isolates showed high resistance rates against ampicillin, tetracycline, and sulfamethoxazole-trimethoprim. The most effective drugs were ceftazidime, ceftriaxone, imipenem and piperacillin-tazobactam, for which no resistance was observed. Differentiation between the diarrheagenic E. coli pathotypes is of great importance since they are involved in acute diarrheal diseases and may require specific antimicrobial chemotherapy. The high antimicrobial resistance observed in our study raises a broad discussion on the

  1. Strong antimicrobial activity of xanthohumol and other derivatives from hops (Humulus lupulus L.) on gut anaerobic bacteria.

    PubMed

    Cermak, Pavel; Olsovska, Jana; Mikyska, Alexandr; Dusek, Martin; Kadleckova, Zuzana; Vanicek, Jiri; Nyc, Otakar; Sigler, Karel; Bostikova, Vanda; Bostik, Pavel

    2017-11-01

    Anaerobic bacteria, such as Bacteroides fragilis or Clostridium perfringens, are part of indigenous human flora. However, Clostridium difficile represents also an important causative agent of nosocomial infectious antibiotic-associated diarrhoea. Treatment of C. difficile infection is problematic, making it imperative to search for new compounds with antimicrobial properties. Hops (Humulus lupulus L.) contain substances with antibacterial properties. We tested antimicrobial activity of purified hop constituents humulone, lupulone and xanthohumol against anaerobic bacteria. The antimicrobial activity was established against B. fragilis, C. perfringens and C. difficile strains according to standard testing protocols (CLSI, EUCAST), and the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were calculated. All C. difficile strains were toxigenic and clinically relevant, as they were isolated from patients with diarrhoea. Strongest antimicrobial effects were observed with xanthohumol showing MIC and MBC values of 15-107 μg/mL, which are close to those of conventional antibiotics in the strains of bacteria with increased resistance. Slightly higher MIC and MBC values were obtained with lupulone followed by higher values of humulone. Our study, thus, shows a potential of purified hop compounds, especially xanthohumol, as alternatives for treatment of infections caused by select anaerobic bacteria, namely nosocomial diarrhoea caused by resistant strains. © 2017 APMIS. Published by John Wiley & Sons Ltd.

  2. Fecal-indicator bacteria in the Allegheny, Monongahela, and Ohio Rivers, near Pittsburgh, Pennsylvania, July-September 2001

    USGS Publications Warehouse

    Fulton, John W.; Buckwalter, Theodore F.

    2004-01-01

    This report presents the results of a study by the Allegheny County Health Department (ACHD) and the U.S. Geological Survey (USGS) to determine the concentrations of fecal-indicator bacteria in the Allegheny, Monongahela, and Ohio Rivers (Three Rivers) in Allegheny County, Pittsburgh, Pa. Water-quality samples and river-discharge measurements were collected from July to September 2001 during dry- (72-hour dry antecedent period), mixed-, and wet-weather (48-hour dry antecedent period and at least 0.3 inch of rain in a 6-hour period) conditions at five sampling sites on the Three Rivers in Allegheny County. Water samples were collected weekly to establish baseline conditions and during successive days after three wet-weather events. Water samples were analyzed for fecal-indicator organisms including fecal-coliform (FC) bacteria, Escherichia coli (E. coli), and enterococci bacteria. Water samples were collected by the USGS and analyzed by the ACHD Laboratory. At each site, left-bank and right-bank surface-water samples were collected in addition to a composite sample (discharge-weighted sample representative of the channel cross section as a whole) at each site. Fecal-indicator bacteria reported in bank and composite samples were used to evaluate the distribution and mixing of bacteria-source streams in receiving waters such as the Three Rivers. Single-event concentrations of enterococci, E. coli, and FC during dry-weather events were greater than State and Federal water-quality standards (WQS) in 11, 28, and 28 percent of the samples, respectively; during mixed-weather events, concentrations of fecal-indicator bacteria were greater than WQS in 28, 37, and 43 percent of the samples, respectively; and during wet-weather events, concentrations of fecal-indicator bacteria were greater than WQS in 56, 71, and 81 percent of samples, respectively. Single-event, wet-weather concentrations exceeded those during dry-weather events for all sites except the Allegheny River at

  3. Prevalence and Antimicrobial Resistance of Vibrio parahaemolyticus Isolated from Raw Shellfish in Poland.

    PubMed

    Lopatek, Magdalena; Wieczorek, Kinga; Osek, Jacek

    2015-05-01

    Vibrio parahaemolyticus is a marine bacterium recognized as an important cause of gastroenteritis in humans consuming contaminated shellfish. In recent years, increasing resistance to ampicillin and aminoglycosides has been observed among V. parahaemolyticus isolates. However, the first-line antimicrobials such as tetracyclines and fluoroquinolones remained highly effective against these bacteria. The aim of this study was to evaluate the occurrence of V. parahaemolyticus in live bivalve molluscs available on the Polish market and to determine the antimicrobial resistance of the recovered isolates. A total of 400 shellfish samples (mussels, oysters, clams, and scallops) from 2009 to 2012 were tested using the International Organization for Standardization standard 21872-1 method and PCR for the species-specific toxR gene. Antimicrobial susceptibility of the isolates was determined using a microbroth dilution method. V. parahaemolyticus was identified in 70 (17.5%) of the 400 samples, and the toxR gene was confirmed in 64 (91.4%) of these isolates. Most of the isolates were recovered from clams (31 isolates; 48.4% prevalence) followed by mussels (17 isolates; 26.6% prevalence). More V. parahaemolyticus-positive samples were found between May and September (22.7% prevalence) than between October and April (11.4% prevalence). Antibiotic profiling revealed that most isolates were resistant to ampicillin (56 isolates; 87.5%) and to streptomycin (45 isolates; 70.3%), but all of them were susceptible to tetracycline and chloramphenicol. Forty-one isolates (64.1%) were resistant to two or more antimicrobials; however, only one isolate (1.6%) was resistant to three antimicrobial classes. The antimicrobials used in treatment of human V. parahaemolyticus infection had high efficacy against the bacterial isolates tested. This study is the first concerning antibiotic resistance of V. parahaemolyticus isolates in Poland, and the results obtained indicate that these bacteria may

  4. Triclosan resistant bacteria in sewage effluent and cross-resistance to antibiotics.

    PubMed

    Coetzee, I; Bezuidenhout, C C; Bezuidenhout, J J

    2017-09-01

    The purpose of this study was to identify triclosan tolerant heterotrophic plate count (HPC) bacteria from sewage effluent and to determine cross-resistance to antibiotics. R2 agar supplemented with triclosan was utilised to isolate triclosan resistant bacteria and 16S rRNA gene sequencing was conducted to identify the isolates. Minimum inhibitory concentrations (MICs) of organisms were determined at selected concentrations of triclosan and cross-resistance to various antibiotics was performed. High-performance liquid chromatography was conducted to quantify levels of triclosan in sewage water. Forty-four HPC were isolated and identified as the five main genera, namely, Bacillus, Pseudomonas, Enterococcus, Brevibacillus and Paenibacillus. MIC values of these isolates ranged from 0.125 mg/L to >1 mg/L of triclosan, while combination of antimicrobials indicated synergism or antagonism. Levels of triclosan within the wastewater treatment plant (WWTP) ranged between 0.026 and 1.488 ppb. Triclosan concentrations were reduced by the WWTP, but small concentrations enter receiving freshwater bodies. Results presented indicate that these levels are sufficient to maintain triclosan resistant bacteria under controlled conditions. Further studies are thus needed into the impact of this scenario on such natural receiving water bodies.

  5. Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik’s Cube of Clinical Microbiology?

    PubMed Central

    Gajdács, Márió; Spengler, Gabriella; Urbán, Edit

    2017-01-01

    Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria. PMID:29112122

  6. Antimicrobial resistance challenged with metal-based antimicrobial macromolecules.

    PubMed

    Abd-El-Aziz, Alaa S; Agatemor, Christian; Etkin, Nola

    2017-02-01

    Antimicrobial resistance threatens the achievements of science and medicine, as it deactivates conventional antimicrobial therapeutics. Scientists respond to the threat by developing new antimicrobial platforms to prevent and treat infections from these resistant strains. Metal-based antimicrobial macromolecules are emerging as an alternative to conventional platforms because they combine multiple mechanisms of action into one platform due to the distinctive properties of metals. For example, metals interact with intracellular proteins and enzymes, and catalyse various intracellular processes. The macromolecular architecture offers a means to enhance antimicrobial activity since several antimicrobial moieties can be conjugated to the scaffold. Further, these macromolecules can be fabricated into antimicrobial materials for contact-killing medical implants, fabrics, and devices. As volatilization or leaching out of the antimicrobial moieties from the macromolecular scaffold is reduced, these medical implants, fabrics, and devices can retain their antimicrobial activity over an extended period. Recent advances demonstrate the potential of metal-based antimicrobial macromolecules as effective platforms that prevent and treat infections from resistant strains. In this review these advances are thoroughly discussed within the context of examples of metal-based antimicrobial macromolecules, their mechanisms of action and biocompatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Antimicrobial Photodynamic Therapy to Kill Gram-negative Bacteria

    PubMed Central

    Sperandio, Felipe F; Huang, Ying-Ying; Hamblin, Michael R

    2013-01-01

    Antimicrobial photodynamic therapy (PDT) or photodynamic inactivation (PDI) is a new promising strategy to eradicate pathogenic microorganisms such as Gram-positive and Gram-negative bacteria, yeasts and fungi. The search for new approaches that can kill bacteria but do not induce the appearance of undesired drug-resistant strains suggests that PDT may have advantages over traditional antibiotic therapy. PDT is a non-thermal photochemical reaction that involves the simultaneous presence of visible light, oxygen and a dye or photosensitizer (PS). Several PS have been studied for their ability to bind to bacteria and efficiently generate reactive oxygen species (ROS) upon photostimulation. ROS are formed through type I or II mechanisms and may inactivate several classes of microbial cells including Gram-negative bacteria such as Pseudomonas aeruginosa, which are typically characterized by an impermeable outer cell membrane that contains endotoxins and blocks antibiotics, dyes, and detergents, protecting the sensitive inner membrane and cell wall. This review covers significant peer-reviewed articles together with US and World patents that were filed within the past few years and that relate to the eradication of Gram-negative bacteria via PDI or PDT. It is organized mainly according to the nature of the PS involved and includes natural or synthetic food dyes; cationic dyes such as methylene blue and toluidine blue; tetrapyrrole derivatives such as phthalocyanines, chlorins, porphyrins, chlorophyll and bacteriochlorophyll derivatives; functionalized fullerenes; nanoparticles combined with different PS; other formulations designed to target PS to bacteria; photoactive materials and surfaces; conjugates between PS and polycationic polymers or antibodies; and permeabilizing agents such as EDTA, PMNP and CaCl2. The present review also covers the different laboratory animal models normally used to treat Gram-negative bacterial infections with antimicrobial PDT. PMID

  8. Comparative Review of Antimicrobial Resistance in Humans and Nonhuman Primates.

    PubMed

    Kim, Jeffrey; Coble, Dondrae J; Salyards, Gregory W; Habing, Gregory G

    2018-04-02

    Antimicrobial resistance (AMR) presents serious threats to human and animal health. Although AMR of pathogens is often evaluated independently between humans and animals, comparative analysis of AMR between humans and animals is necessary for zoonotic pathogens. Major surveillance systems monitor AMR of zoonotic pathogens in humans and food animals, but comprehensive AMR data in veterinary medicine is not diligently monitored for most animal species with which humans commonly contact, including NHP. The objective of this review is to provide a complete report of the prevalences of AMR among zoonotic bacteria that present the greatest threats to NHP, occupational, and public health. High prevalences of AMR exist among Shigella, Campylobacter, and Yersinia, including resistance to antimicrobials important to public health, such as macrolides. Despite improvements in regulations, standards, policies, practices, and zoonotic awareness, occupational exposures to and illnesses due to zoonotic pathogens continue to be reported and, given the documented prevalences of AMR, constitute an occupational and public health risk. However, published literature is sparse, thus indicating the need for veterinarians to proactively monitor AMR in dangerous zoonotic bacteria, to enable veterinarians to make more informed decisions to maximize antimicrobial therapy and minimize occupational risk.

  9. Comparative Review of Antimicrobial Resistance in Humans and Nonhuman Primates.

    PubMed

    Kim, Jeffrey; Coble, Dondrae J; Salyards, Gregory W; Habing, Gregory G

    2019-03-01

    Antimicrobial resistance (AMR) presents serious threats to human and animal health. Although AMR of pathogens is often evaluated independently between humans and animals, comparative analysis of AMR between humans and animals is necessary for zoonotic pathogens. Major surveillance systems monitor AMR of zoonotic pathogens in humans and food animals, but comprehensive AMR data in veterinary medicine is not diligently monitored for most animal species with which humans commonly contact, including NHP. The objective of this review is to provide a complete report of the prevalences of AMR among zoonotic bacteria that present the greatest threats to NHP, occupational, and public health. High prevalences of AMR exist among Shigella, Campylobacter, and Yersinia, including resistance to antimicrobials important to public health, such as macrolides. Despite improvements in regulations, standards, policies, practices, and zoonotic awareness, occupational exposures to and illnesses due to zoonotic pathogens continue to be reported and, given the documented prevalences of AMR, constitute an occupational and public health risk. However, published literature is sparse, thus indicating the need for veterinarians to proactively monitor AMR in dangerous zoonotic bacteria, to enable veterinarians to make more informed decisions to maximize antimicrobial therapy and minimize occupational risk.

  10. Impact of Some Ecological Factors on Fecal Contamination of Drinking Water by Diarrheagenic Antibiotic-Resistant Escherichia coli in Zagazig City, Egypt

    PubMed Central

    Gohar, Maha Kamal; Atta, Amal Hassan

    2016-01-01

    Fecal contamination of drinking water is a major health problem which accounts for many cases of diarrhea mainly in infants and foreigners. This contamination is a complex interaction of many parameters. Antibiotic resistance among bacterial isolates complicates the problem. The study was done to identify fecal contamination of drinking water by Diarrheagenic Antibiotic-Resistant Escherichia coli in Zagazig city and to trace reasons for such contamination, three hundred potable water samples were investigated for E. coli existence. Locations of E. coli positive samples were investigated in relation to population density, water source, and type of water pipe. Sixteen E. coli strains were isolated. Antibiotic sensitivity was done and enterotoxigenic, enteropathogenic, and enterohaemorrhagic virulence genes were investigated by PCR. Probability of fecal contamination correlated with higher population density, with increased distance from Zagazig water plant, and with asbestos cement water pipes. Resistance to at least one antimicrobial drug was found in all isolates. Virulence genes were detected in a rate of 26.27%, 13.13%, 20%, 6.67%, and 33.33% for LT, ST, stx1, stx2, and eae genes, respectively. This relatively high frequency of fecal contamination points towards the high risk of developing diarrhea by antibiotic resistant DEC in low socioeconomic communities particularly with old fashion distribution systems. PMID:27725834

  11. Survival, transport, and sources of fecal bacteria in streams and survival in land-applied poultry litter in the upper Shoal Creek basin, southwestern Missouri, 2001-2002

    USGS Publications Warehouse

    Schumacher, John G.

    2003-01-01

    Densities of fecal coliform bacteria along a 5.7-mi (mile) reach of Shoal Creek extending upstream from State Highway 97 (site 3) to State Highway W (site 2) and in two tributaries along this reach exceeded the Missouri Department of Natural Resources (MDNR) standard of 200 col/100 mL (colonies per 100 milliliters) for whole-body contact recreation. A combination of techniques was used in this report to provide information on the source, transport, and survival of fecal bacteria along this reach of Shoal Creek. Results of water-quality samples collected during dye-trace and seepage studies indicated that at summer low base-flow conditions, pastured cattle likely were a substantial source of fecal bacteria in Shoal Creek at the MDNR monitoring site (site 3) at State Highway 97. Using repeat element Polymerase Chain Reaction (rep-PCR), cattle were the presumptive source of about 50 percent of the Escherichia coli (E. coli) isolates in water samples from site 3. Cattle, horses, and humans were the most common presumptive source of E. coli isolates at sites further upstream. Poultry was identified by rep-PCR as a major source of E. coli in Pogue Creek, a tributary in the upper part of the study area. Results of the rep-PCR were in general agreement with the detection and distribution of trace concentrations of organic compounds commonly associated with human wastewater, such as caffeine, the antimicrobial agent triclosan, and the pharmaceutical compounds acetaminophen and thiabendazole (a common cattle anthelmintic). Significant inputs of fecal bacteria to Shoal Creek occurred along a 1.6-mi reach of Shoal Creek immediately upstream from site 3. During a 36-hour period in July 2001, average densities of fecal coliform and E. coli bacteria increased from less than or equal to 500 col/100 mL upstream from this stream reach (sample site 2c) to 2,100 and 1,400 col/100 mL, respectively, at the MDNR sampling site. Fecal bacteria densities exhibited diurnal variability at all

  12. Addressing Antimicrobial Resistance: An Overview of Priority Actions to Prevent Suboptimal Antimicrobial Use in Food-Animal Production

    PubMed Central

    Lhermie, Guillaume; Gröhn, Yrjö T.; Raboisson, Didier

    2017-01-01

    The growing concern regarding emergence of bacteria resistant to antimicrobials and their potential for transmission to humans via animal production has led various authorities worldwide to implement measures to decrease antimicrobial use (AMU) in livestock production. These measures are influenced by those implemented in human medicine, and emphasize the importance of antimicrobial stewardship, surveillance, infection prevention and control and research. In food producing animals, unlike human medicine, antimicrobials are used to control diseases which cause economic losses. This major difference may explain the failure of the public policies implemented to control antimicrobial usage. Here we first review the specific factors influencing AMU across the farm animal sector and highlighting the farmers’ decision-making process of AMU. We then discuss the efficiency of existing regulations implemented by policy makers, and assess the need for alternative strategies, such as substitution between antimicrobials and other measures for infectious disease control. We also discuss the interests of regulating antimicrobial prices. Finally, we emphasize the value of optimizing antimicrobial regimens, and developing veterinary precision medicine to achieve clinical efficacy in animals while limiting negative impacts on public health. The fight against antimicrobial resistance requires both a reduction and an optimization of antimicrobial consumption. The set of actions currently implemented by policy makers does not adequately address the economic interests of farmers’ use of antimicrobials. PMID:28111568

  13. Myrcia ovata Cambessedes essential oils: A proposal for a novel natural antimicrobial against foodborne bacteria.

    PubMed

    de Jesus, Isabela Cristina; Santos Frazão, Gladslene Góes; Blank, Arie Fitzgerald; de Aquino Santana, Luciana Cristina Lins

    2016-10-01

    This paper reports the innovative antibacterial activity of essential oils (EOs) from nine Myrcia ovata Cambessedes plants against eight foodborne bacteria. Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Enterococcus faecalis and Pseudomonas aeruginosa were the most susceptible bacteria to EOs. In particular, the P. aeruginosa, which is usually resistant to antimicrobials agents, was extremely sensitive to some EOs. The gram-positive and gram-negative bacteria were inhibited and eliminated with minimum EOs concentrations ranging from 0.78 to 25 μL/mL. The Serratia marcensces and Escherichia coli were less susceptible to EOs alone. Consequently, some EOs combinations were investigated by checkerboard method against these bacteria and a synergistic effect was obtained. Myrcia ovata Cambessedes EOs showed high inhibitory and bactericidal effects against foodborne bacteria might be an interesting alternative for future applications as natural antimicrobials in food systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Surveillance of antimicrobial resistance in Lebanese hospitals: retrospective nationwide compiled data.

    PubMed

    Chamoun, Kamal; Farah, Maya; Araj, Georges; Daoud, Ziad; Moghnieh, Rima; Salameh, Pascale; Saade, Danielle; Mokhbat, Jacques; Abboud, Emme; Hamze, Monzer; Abboud, Edmond; Jisr, Tamima; Haddad, Antoine; Feghali, Rita; Azar, Nadim; El-Zaatari, Mohammad; Chedid, Marwan; Haddad, Christian; Zouain Dib Nehme, Mireille; Barakat, Angelique; Husni, Rola

    2016-05-01

    Antimicrobial resistance is closely linked to antimicrobial use and is a growing concern worldwide. Antimicrobial resistance increases healthcare costs substantially in many countries, including Lebanon. National data from Lebanon have, in the most part, been limited to a few academic hospitals. The Lebanese Society of Infectious Diseases conducted a retrospective study to better describe the antimicrobial susceptibility patterns of bacterial isolates in Lebanon. Data were based on records retrieved from the bacteriology laboratories of 16 different Lebanese hospitals between January 2011 and December 2013. The susceptibility results of a total 20684 Gram-positive and 55594 Gram-negative bacteria were analyzed. The prevalence rate of methicillin-resistant Staphylococcus aureus was 27.6% and of vancomycin-resistant Enterococcus spp was 1%. Streptococcus pneumoniae had susceptibilities of 46% to oxacillin, 63% to erythromycin, and 98% to levofloxacin. Streptococcus pyogenes had susceptibilities of 94% to erythromycin and 95% to clindamycin. The mean ampicillin susceptibility of Haemophilus influenzae, Salmonella spp, and Shigella spp isolates was 79%, 81.3%, and 62.2%, respectively. The extended-spectrum beta-lactamase production rate for Escherichia coli was 32.3% and for Klebsiella spp was 29.2%. Acinetobacter spp showed high resistance to most antimicrobials, with low resistance to colistin (17.1%). Pseudomonas spp susceptibilities to piperacillin-tazobactam and imipenem were lower than 80% (79.7% and 72.8%, respectively). This study provides population-specific data that are valuable in guiding antimicrobial use in Lebanon and neighbouring countries and will help in the establishment of a surveillance system for antimicrobial resistance following the implementation of a nationwide standardization of laboratory methods and data entry. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Isolation and identification of local bacteria endophyte and screening of its antimicrobial property against pathogenic bacteria and fungi

    NASA Astrophysics Data System (ADS)

    Fikri, Ahmad Syairazie Ibrahim; Rahman, Irman Abdul; Nor, Norefrina Shafinaz Md; Hamzah, Ainon

    2018-04-01

    Endophytes are organisms, often fungi and bacteria that live in living plant cells. These organisms reside in the living tissues of the host plant in a variety of relationships, ranging from symbiotic to slightly pathogenic. The endophytes may produce a plethora of substances that have potential to be used in modern medicine, agriculture and industry. The aims of this study are to isolate, identify and screening antimicrobial activity of bacterial endophytes. The endophytes were isolated using nutrient agar, incubated at 37°C for 48 hours. Identification of the isolates were done based on morphological characteristics, biochemical tests and 16S rDNA molecular analysis. Disk diffusion method was used to screen for antimicrobial activity of metabolites from endophytes against pathogenic bacteria. Screening for antifungal activity of selected endophytes was done using dual culture method againts pathogenic fungi followed by Kirby-Bauer method. Results showed endophytes designated as B2c and B7b have positive antimicrobial activity. The metabolites from isolate B2c showed antimicrobial activity against pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus and Staphylococcus epidermis, while isolate B7b have positive activities againts MRSA, S. aureus and Pseudomonas aeruginosa. Isolates B2c displayed antifungal activity against Fusarium oxysporum, Fusarium solani, Phytophthora palmivora and Colletotrichum gloeosporioides. Identification using biochemical tests and 16S rDNA sequences identified isolate B2c as Pseudomonas resinovorans with 97% homology and isolate B7b as Bacillus subtilis with 98% homology.

  16. Transfer of Multidrug-Resistant Bacteria between Intermingled Ecological Niches: The Interface between Humans, Animals and the Environment

    PubMed Central

    da Costa, Paulo Martins; Loureiro, Luís; Matos, Augusto J. F.

    2013-01-01

    The use of antimicrobial agents has been claimed to be the driving force for the emergence and spread of microbial resistance. However, several studies have reported the presence of multidrug-resistant bacteria in populations exposed to low levels of antimicrobial drugs or even never exposed. For many pathogens, especially those organisms for which asymptomatic colonization typically precedes infection (e.g., Enterococcus spp. and Escherichia coli), the selective effects of antimicrobial use can only be understood if we considerer all biological and environmental pathways which enable these bacteria, and the genes they carry, to spread between different biomes. This ecological framework provides an essential perspective for formulating antimicrobial use policies, precisely because it encompasses the root causes of these problems rather than merely their consequences. PMID:23343983

  17. Monte Carlo Simulations Suggest Current Chlortetracycline Drug-Residue Based Withdrawal Periods Would Not Control Antimicrobial Resistance Dissemination from Feedlot to Slaughterhouse.

    PubMed

    Cazer, Casey L; Ducrot, Lucas; Volkova, Victoriya V; Gröhn, Yrjö T

    2017-01-01

    Antimicrobial use in beef cattle can increase antimicrobial resistance prevalence in their enteric bacteria, including potential pathogens such as Escherichia coli . These bacteria can contaminate animal products at slaughterhouses and cause food-borne illness, which can be difficult to treat if it is due to antimicrobial resistant bacteria. One potential intervention to reduce the dissemination of resistant bacteria from feedlot to consumer is to impose a withdrawal period after antimicrobial use, similar to the current withdrawal period designed to prevent drug residues in edible animal meat. We investigated tetracycline resistance in generic E. coli in the bovine large intestine during and after antimicrobial treatment by building a mathematical model of oral chlortetracycline pharmacokinetics-pharmacodynamics and E. coli population dynamics. We tracked three E. coli subpopulations (susceptible, intermediate, and resistant) during and after treatment with each of three United States chlortetracycline indications (liver abscess reduction, disease control, disease treatment). We compared the proportion of resistant E. coli before antimicrobial use to that at several time points after treatment and found a greater proportion of resistant enteric E. coli after the current withdrawal periods than prior to treatment. In order for the proportion of resistant E. coli in the median beef steer to return to the pre-treatment level, withdrawal periods of 15 days after liver abscess reduction dosing (70 mg daily), 31 days after disease control dosing (350 mg daily), and 36 days after disease treatment dosing (22 mg/kg bodyweight for 5 days) are required in this model. These antimicrobial resistance withdrawal periods would be substantially longer than the current U.S. withdrawals of 0-2 days or Canadian withdrawals of 5-10 days. One published field study found similar time periods necessary to reduce the proportion of resistant E. coli following chlortetracycline disease

  18. Monte Carlo Simulations Suggest Current Chlortetracycline Drug-Residue Based Withdrawal Periods Would Not Control Antimicrobial Resistance Dissemination from Feedlot to Slaughterhouse

    PubMed Central

    Cazer, Casey L.; Ducrot, Lucas; Volkova, Victoriya V.; Gröhn, Yrjö T.

    2017-01-01

    Antimicrobial use in beef cattle can increase antimicrobial resistance prevalence in their enteric bacteria, including potential pathogens such as Escherichia coli. These bacteria can contaminate animal products at slaughterhouses and cause food-borne illness, which can be difficult to treat if it is due to antimicrobial resistant bacteria. One potential intervention to reduce the dissemination of resistant bacteria from feedlot to consumer is to impose a withdrawal period after antimicrobial use, similar to the current withdrawal period designed to prevent drug residues in edible animal meat. We investigated tetracycline resistance in generic E. coli in the bovine large intestine during and after antimicrobial treatment by building a mathematical model of oral chlortetracycline pharmacokinetics-pharmacodynamics and E. coli population dynamics. We tracked three E. coli subpopulations (susceptible, intermediate, and resistant) during and after treatment with each of three United States chlortetracycline indications (liver abscess reduction, disease control, disease treatment). We compared the proportion of resistant E. coli before antimicrobial use to that at several time points after treatment and found a greater proportion of resistant enteric E. coli after the current withdrawal periods than prior to treatment. In order for the proportion of resistant E. coli in the median beef steer to return to the pre-treatment level, withdrawal periods of 15 days after liver abscess reduction dosing (70 mg daily), 31 days after disease control dosing (350 mg daily), and 36 days after disease treatment dosing (22 mg/kg bodyweight for 5 days) are required in this model. These antimicrobial resistance withdrawal periods would be substantially longer than the current U.S. withdrawals of 0–2 days or Canadian withdrawals of 5–10 days. One published field study found similar time periods necessary to reduce the proportion of resistant E. coli following chlortetracycline disease

  19. [Investigation of antimicrobial resistance of Klebsiella pneumoniae and Pseudomonas aeruginosa isolates from rat-like animals around a hospital in Guangzhou].

    PubMed

    Zhong, Xue-Shan; Ge, Jing; Chen, Shao-Wei; Xiong, Yi-Quan; Zheng, Xue-Yan; Qiu, Min; Huo, Shu-Ting; Chen, Qing

    2016-05-01

    To investigate antimicrobial resistance of Klebsiella pneumoniae and Pseudomonas aeruginosa isolates in fecal samples from rat-like animals. Rat-like animals were captured using cages around a hospital and the neighboring residential area between March and October, 2015. K. pneumoniae and P. aeruginosa were isolated from the fecal samples of the captured animals. Antimicrobial susceptibility test was performed according to the guidelines of Clinical and Laboratory Standards Institute (2014). A total of 329 rat-like animals were captured, including 205 Suncus murinus, 111 Rattus norvegicus, 5 Rattus flavipectus and 8 Mus musculus. The positivity rates of K. pneumoniae and P. aeruginosa were 78.4% and 34.7% in the fecal samples from the captured animals, respectively. K. pneumoniae isolates from Suncus murinus showed a high resistance to ampicillin, cephazolin, nitrofurantoin, piperacillin and cefotaxime (with resistance rates of 100%, 51.2%, 44.2%, 37.2%, and 23.3%, respectively), and K. pneumoniae isolates from Rattus spp. showed a similar drug-resistance profile. The prevalence rates of multidrug resistance and ESBLs were 40.9% and 10.7%, respectively. P. aeruginosa from both Suncus murinus and Rattus spp. exhibited the highest resistance rates to aztreonam (12.4% and 16.0%, respectively), followed by penicillins and fluoroquinolones. P. aeruginosa isolates were susceptible to cephems, aminoglycosides and carbapenems (with resistance rates below 5%). K. pneumoniae and P. aeruginosa isolated from rat-like animals showed drug-resistance profiles similar to those of the strains isolated from clinical patients, suggesting that the possible transmission of K. pneumoniae and P. aeruginosa between rat-like animals and human beings.

  20. Multidrug-Resistant Enterococcal Infections: New Compounds, Novel Antimicrobial Therapies?

    PubMed

    van Harten, Roel M; Willems, Rob J L; Martin, Nathaniel I; Hendrickx, Antoni P A

    2017-06-01

    Over the past two decades infections due to antibiotic-resistant bacteria have escalated world-wide, affecting patient morbidity, mortality, and health care costs. Among these bacteria, Enterococcus faecium and Enterococcus faecalis represent opportunistic nosocomial pathogens that cause difficult-to-treat infections because of intrinsic and acquired resistance to a plethora of antibiotics. In recent years, a number of novel antimicrobial compound classes have been discovered and developed that target Gram-positive bacteria, including E. faecium and E. faecalis. These new antibacterial agents include teixobactin (targeting lipid II and lipid III), lipopeptides derived from nisin (targeting lipid II), dimeric vancomycin analogues (targeting lipid II), sortase transpeptidase inhibitors (targeting the sortase enzyme), alanine racemase inhibitors, lipoteichoic acid synthesis inhibitors (targeting LtaS), various oxazolidinones (targeting the bacterial ribosome), and tarocins (interfering with teichoic acid biosynthesis). The targets of these novel compounds and mode of action make them very promising for further antimicrobial drug development and future treatment of Gram-positive bacterial infections. Here we review current knowledge of the most favorable anti-enterococcal compounds along with their implicated modes of action and efficacy in animal models to project their possible future use in the clinical setting. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. The prevalence of antimicrobial-resistant Escherichia coli in sympatric wild rodents varies by season and host.

    PubMed

    Williams, N J; Sherlock, C; Jones, T R; Clough, H E; Telfer, S E; Begon, M; French, N; Hart, C A; Bennett, M

    2011-04-01

      To investigate the prevalence and temporal patterns of antimicrobial resistance in wild rodents with no apparent exposure to antimicrobials.   Two sympatric populations of bank voles and wood mice were trapped and individually monitored over a 2- year period for faecal carriage of antimicrobial-resistant Escherichia coli. High prevalences of ampicillin-, chloramphenicol-, tetracycline- and trimethoprim-resistant E. coli were observed. A markedly higher prevalence of antimicrobial-resistant E. coli was found in wood mice than in bank voles, with the prevalence in both increasing over time. Superimposed on this trend was a seasonal cycle with a peak prevalence of resistant E. coli in mice in early- to mid-summer and in voles in late summer and early autumn.   These sympatric rodent species had no obvious contact with antimicrobials, and the difference in resistance profiles between rodent species and seasons suggests that factors present in their environment are unlikely to be drivers of such resistance.   These findings suggest that rodents may represent a reservoir of antimicrobial-resistant bacteria, transmissible to livestock and man. Furthermore, such findings have implications for human and veterinary medicine regarding antimicrobial usage and subsequent selection of antimicrobial-resistant organisms. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  2. Antimicrobial property of lemongrass (Cymbopogon citratus) oil against pathogenic bacteria isolated from pet turtles.

    PubMed

    De Silva, B C J; Jung, Won-Gi; Hossain, Sabrina; Wimalasena, S H M P; Pathirana, H N K S; Heo, Gang-Joon

    2017-06-01

    The usage of essential oils as antimicrobial agents is gaining attention. Besides, pet turtles were known to harbor a range of pathogenic bacteria while the turtle keeping is a growing trend worldwide.The current study examined the antimicrobial activity of lemon grass oil (LGO) against seven species of Gram negative bacteria namely; Aeromonas hydrophila , A. caviae , Citrobacter freundii , Salmonella enterica , Edwardsiella tarda , Pseudomonas aeruginosa , and Proteus mirabilis isolated from three popular species of pet turtles. Along with the results of disc diffusion, minimum inhibitory and minimum bactericidal concentration (MIC and MBC) tests, LGO was detected as effective against 6 species of bacteria excluding P. aeruginosa . MIC of LGO for the strains except P. aeruginosa ranged from 0.016 to 0.5% (V/V). The lowest MIC recorded in the E. tarda strain followed by A. hydrophilla , C. freundii , P. mirabilis , and S. enterica . Interestingly, all the bacterial species except E. tarda were showing high multiple antimicrobial resistance (MAR) index values ranging from 0.36 to 0.91 upon the 11 antibiotics tested although they were sensitive to LGO.

  3. Antimicrobial property of lemongrass (Cymbopogon citratus) oil against pathogenic bacteria isolated from pet turtles

    PubMed Central

    De Silva, B.C.J.; Jung, Won-Gi; Hossain, Sabrina; Wimalasena, S.H.M.P.; Pathirana, H.N.K.S.

    2017-01-01

    The usage of essential oils as antimicrobial agents is gaining attention. Besides, pet turtles were known to harbor a range of pathogenic bacteria while the turtle keeping is a growing trend worldwide.The current study examined the antimicrobial activity of lemon grass oil (LGO) against seven species of Gram negative bacteria namely; Aeromonas hydrophila, A. caviae, Citrobacter freundii, Salmonella enterica, Edwardsiella tarda, Pseudomonas aeruginosa, and Proteus mirabilis isolated from three popular species of pet turtles. Along with the results of disc diffusion, minimum inhibitory and minimum bactericidal concentration (MIC and MBC) tests, LGO was detected as effective against 6 species of bacteria excluding P. aeruginosa. MIC of LGO for the strains except P. aeruginosa ranged from 0.016 to 0.5% (V/V). The lowest MIC recorded in the E. tarda strain followed by A. hydrophilla, C. freundii, P. mirabilis, and S. enterica. Interestingly, all the bacterial species except E. tarda were showing high multiple antimicrobial resistance (MAR) index values ranging from 0.36 to 0.91 upon the 11 antibiotics tested although they were sensitive to LGO. PMID:28747972

  4. Antimicrobial susceptibility of clinically isolated anaerobic bacteria in a University Hospital Centre Split, Croatia in 2013.

    PubMed

    Novak, Anita; Rubic, Zana; Dogas, Varja; Goic-Barisic, Ivana; Radic, Marina; Tonkic, Marija

    2015-02-01

    Anaerobic bacteria play a significant role in many endogenous polymicrobial infections. Since antimicrobial resistance among anaerobes has increased worldwide, it is useful to provide local susceptibility data to guide empirical therapy. The present study reports recent data on the susceptibility of clinically relevant anaerobes in a University Hospital Centre (UHC) Split, Croatia. A total of 63 Gram-negative and 59 Gram-positive anaerobic clinical isolates from various body sites were consecutively collected from January to December 2013. Antimicrobial susceptibility testing was performed using standardized methods and interpreted using EUCAST criteria. Patient's clinical and demographic data were recorded by clinical microbiologist. Among 35 isolates of Bacteroides spp., 97.1% were resistant to penicillin (PCN), 5.7% to amoxicillin/clavulanic acid (AMC), 8.6% to piperacillin/tazobactam (TZP), 29.0% to clindamycin (CLI) and 2.9% to metronidazole (MZ). Percentages of susceptible strains to imipenem (IPM), meropenem (MEM) and ertapenem (ETP) were 94.3. Resistance of other Gram-negative bacilli was 76.0% to PCN, 8.0% to AMC, 12.0% to TZP, 28.0% to CLI and 8% to MZ. All other Gram-negative strains were fully susceptible to MEM and ETP, while 96.0% were susceptible to IPM. Clostridium spp. isolates were 100% susceptible to all tested antibiotics except to CLI (two of four tested isolates were resistant). Propionibacterium spp. showed resistance to CLI in 4.3%, while 100% were resistant to MZ. Among other Gram-positive bacilli, 18.2% were resistant to PCN, 9.1% to CLI and 54.5% to MZ, while 81.8% of isolates were susceptible to carbapenems. Gram-positive cocci were 100% susceptible to all tested antimicrobials except to MZ, where 28.6% of resistant strains were recorded. Abdomen was the most common source of isolates (82.5%). The most prevalent types of infection were abscess (22.1%), sepsis (14.8%), appendicitis (13.9%) and peritonitis (6.6%). Twenty four patients (19

  5. Antimicrobial Use and Antimicrobial Resistance: A Population Perspective

    PubMed Central

    Samore, Matthew H.

    2002-01-01

    The need to stem the growing problem of antimicrobial resistance has prompted multiple, sometimes conflicting, calls for changes in the use of antimicrobial agents. One source of disagreement concerns the major mechanisms by which antibiotics select resistant strains. For infections like tuberculosis, in which resistance can emerge in treated hosts through mutation, prevention of antimicrobial resistance in individual hosts is a primary method of preventing the spread of resistant organisms in the community. By contrast, for many other important resistant pathogens, such as penicillin-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus faecium resistance is mediated by the acquisition of genes or gene fragments by horizontal transfer; resistance in the treated host is a relatively rare event. For these organisms, indirect, population-level mechanisms of selection account for the increase in the prevalence of resistance. These mechanisms can operate even when treatment has a modest, or even negative, effect on an individual host’s colonization with resistant organisms. PMID:11971765

  6. Antimicrobial resistance mechanisms and potential synthetic treatments.

    PubMed

    Ali, Junaid; Rafiq, Qasim A; Ratcliffe, Elizabeth

    2018-04-01

    Since the discovery of antibiotics by Sir Alexander Fleming they have been used throughout medicine and play a vital role in combating microorganisms. However, with their vast use, development of resistance has become more prevalent and their use is currently under threat. Antibiotic resistance poses a global threat to human and animal health, with many bacterial species having developed some form of resistance and in some cases within a year of first exposure to antimicrobial agents. This review aims to examine some of the mechanisms behind resistance. Additionally, re-engineering organisms, re-sensitizing bacteria to antibiotics and gene-editing techniques such as the clustered regularly interspaced short palindromic repeats-Cas9 system are providing novel approaches to combat bacterial resistance. To that extent, we have reviewed some of these novel and innovative technologies.

  7. Using Genome-Editing Technologies to Mitigate Antimicrobial Resistance [CRISPR-Based Antibacterials: Transforming Bacterial Defense into Offense

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Greene, Adrienne C.

    The development of antimicrobial-resistant (AMR) bacteria poses a serious worldwide health concern. CRISPR-based antibacterials, however, are a novel and adaptable method for building an arsenal of antibacterials potentially capable of targeting any pathogenic bacteria.

  8. Antimicrobial resistance: A global emerging threat to public health systems.

    PubMed

    Ferri, Maurizio; Ranucci, Elena; Romagnoli, Paola; Giaccone, Valerio

    2017-09-02

    Antimicrobial resistance (AMR) became in the last two decades a global threat to public health systems in the world. Since the antibiotic era, with the discovery of the first antibiotics that provided consistent health benefits to human medicine, the misuse and abuse of antimicrobials in veterinary and human medicine have accelerated the growing worldwide phenomenon of AMR. This article presents an extensive overview of the epidemiology of AMR, with a focus on the link between food producing-animals and humans and on the legal framework and policies currently implemented at the EU level and globally. The ways of responding to the AMR challenges foresee an array of measures that include: designing more effective preventive measures at farm level to reduce the use of antimicrobials; development of novel antimicrobials; strengthening of AMR surveillance system in animal and human populations; better knowledge of the ecology of resistant bacteria and resistant genes; increased awareness of stakeholders on the prudent use of antibiotics in animal productions and clinical arena; and the public health and environmental consequences of AMR. Based on the global nature of AMR and considering that bacterial resistance does not recognize barriers and can spread to people and the environment, the article ends with specific recommendations structured around a holistic approach and targeted to different stakeholders.

  9. Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria

    PubMed Central

    Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

    2014-01-01

    Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds. PMID:24663118

  10. Antioxidant and antimicrobial potential of the Bifurcaria bifurcata epiphytic bacteria.

    PubMed

    Horta, André; Pinteus, Susete; Alves, Celso; Fino, Nádia; Silva, Joana; Fernandez, Sara; Rodrigues, Américo; Pedrosa, Rui

    2014-03-24

    Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.

  11. Selection of broad-spectrum cephalosporin-resistant Escherichia coli in the feces of healthy dogs after administration of first-generation cephalosporins.

    PubMed

    Kimura, Ayako; Yossapol, Montira; Shibata, Sanae; Asai, Tetsuo

    2017-01-01

    Although antimicrobial products are essential for treating diseases caused by bacteria, antimicrobial treatment selects for antimicrobial-resistant (AMR) bacteria. The aim of this study was to determine the effects of administration of first-generation cephalosporins on development of resistant Escherichia coli in dog feces. The proportions of cephalexin (LEX)-resistant E. coli in fecal samples of three healthy dogs treated i.v. with cefazolin before castration and then orally with LEX for 3 days post-operation (PO) were examined using DHL agar with or without LEX (50 µg/mL). LEX-resistant E. coli were found within 3 days PO, accounted for 100% of all identified E. coli 3-5 days PO in all dogs, and were predominantly found until 12 days PO. LEX-resistant E. coli isolates on DHL agar containing LEX were subjected to antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) genotyping, β-lactamase typing and plasmid profiling. All isolates tested exhibited cefotaxime (CTX) resistance (CTX minimal inhibitory concentration ≥4 µg/mL). Seven PFGE profiles were classified into five groups and three β-lactamase combinations (bla CMY-4 -bla TEM-1 , bla TEM-1 -bla CTX-M-15 and bla TEM-1 -bla CTX-M-15 -bla CMY-4 ). All isolates exhibited identical PFGE profiles in all dogs on four days PO and subsequently showed divergent PFGE profiles. Our results indicate there are two selection periods for AMR bacteria resulting from the use of antimicrobials. Thus, continuing hygiene practices are necessary to prevent AMR bacteria transfer via dog feces after antimicrobial administration. © 2017 The Societies and John Wiley & Sons Australia, Ltd.

  12. Pilot Screening to Determine Antimicrobial Synergies in a Multidrug-Resistant Bacterial Strain Library

    PubMed Central

    Kim, Si-Hyun; Park, Chulmin; Chun, Hye-Sun; Choi, Jae-Ki; Lee, Hyo-Jin; Cho, Sung-Yeon; Park, Sun Hee; Choi, Su-Mi; Choi, Jung-Hyun; Yoo, Jin-Hong

    2016-01-01

    With the rise in multidrug-resistant (MDR) bacterial infections, there has been increasing interest in combinations of ≥2 antimicrobial agents with synergistic effects. We established an MDR bacterial strain library to screen for in vitro antimicrobial synergy by using a broth microdilution checkerboard method and high-throughput luciferase-based bacterial cell viability assay. In total, 39 MDR bacterial strains, including 23 carbapenem-resistant gram-negative bacteria, 9 vancomycin-intermediate Staphylococcus aureus, and 7 vancomycin-resistant Enterococcus faecalis, were used to screen for potential antimicrobial synergies. Synergies were more frequently identified with combinations of imipenem plus trimethoprim–sulfamethoxazole for carbapenem-resistant Acinetobacter baumannii in the library. To verify this finding, we tested 34 A. baumannii clinical isolates resistant to both imipenem and trimethoprim–sulfamethoxazole by the checkerboard method. The imipenem plus trimethoprim–sulfamethoxazole combination showed synergy in the treatment of 21 (62%) of the clinical isolates. The results indicate that pilot screening for antimicrobial synergy in the MDR bacterial strain library could be valuable in the selection of combination therapeutic regimens to treat MDR bacterial infections. Further studies are warranted to determine whether this screening system can be useful to screen for the combined effects of conventional antimicrobials and new-generation antimicrobials or nonantimicrobials. PMID:26974861

  13. Studies on tridecaptin B(1), a lipopeptide with activity against multidrug resistant Gram-negative bacteria.

    PubMed

    Cochrane, Stephen A; Lohans, Christopher T; van Belkum, Marco J; Bels, Manon A; Vederas, John C

    2015-06-07

    Previously other groups had reported that Paenibacillus polymyxa NRRL B-30507 produces SRCAM 37, a type IIA bacteriocin with antimicrobial activity against Campylobacter jejuni. Genome sequencing and isolation of antimicrobial compounds from this P. polymyxa strain show that the antimicrobial activity is due to polymyxins and tridecaptin B1. The complete structural assignment, synthesis, and antimicrobial profile of tridecaptin B1 is reported, as well as the putative gene cluster responsible for its biosynthesis. This peptide displays strong activity against multidrug resistant Gram-negative bacteria, a finding that is timely to the current problem of antibiotic resistance.

  14. Photodynamic inactivation of antibiotic-resistant bacteria and biofilms by hematoporphyrin monomethyl ether.

    PubMed

    Liu, Chengcheng; Hu, Min; Ma, Dandan; Lei, Jin'e; Xu, Jiru

    2016-02-01

    The worldwide increase in bacterial antibiotic resistance has led to a search for alternative antibacterial therapies. A promising approach to killing antibiotic-resistant bacteria is photodynamic antimicrobial chemotherapy, which uses light in combination with a photosensitizer to induce a phototoxic reaction. We evaluated the photodynamic inactivation (PDI) efficiency of hematoporphyrin monomethyl ether (HMME) on antibiotic-resistant bacteria and biofilms. HMME exhibited no significant dark toxicity and provided dose-dependent inactivation of antibiotic-resistant bacteria and biofilms. After incubation with 100-μM HMME and irradiation with 72-J cm(-2) white light, 4.19-7.59 log10 reductions in survival were achieved in planktonic suspension. Antibiotic-resistant strains were as susceptible to PDI in biofilms as in planktonic suspensions, but the inactivation of bacterial cells in biofilms was attenuated. In addition, gram-positive bacterial strains and biofilms were more susceptible than gram-negative strains and biofilms to the PDI effect of HMME. Thus, HMME is a promising photosensitizer for the treatment of infectious diseases caused by antibiotic-resistant bacteria, especially gram-positive bacteria.

  15. Determination of antimicrobial resistance to extended-spectrum cephalosporin, quinolones, and vancomycin in selected human enteric pathogens from Prince Edward Island, Canada.

    PubMed

    Awosile, Babafela; German, Gregory; Rodriguez-Lecompte, Juan Carlos; Saab, Matthew E; Heider, Luke C; McClure, J Trenton

    2018-04-05

    The aim of this study was to determine the frequency of fecal carriage of vancomycin-resistant Enterococcus spp. and Escherichia coli with reduced susceptibilities to extended-spectrum cephalosporins (ESCs) and quinolones in humans on Prince Edward Island, Canada. Convenience fecal samples from individuals on Prince Edward Island were screened phenotypically using selective culture and genotypically using multiplex polymerase chain reactions to detect E. coli and Enterococcus spp. resistant to critically important antimicrobials. Twenty-six (5.3%) of 489 individuals had E. coli with reduced susceptibility to ESCs. Twenty-five (96.2%) of the 26 isolates harbored bla TEM , 18 (69.2%) harbored bla CMY-2 , 16 (61.5%) harbored bla CTX-M groups, 2 (7.7%) harbored bla SHV genes. None of the ESC-resistant E. coli was positive for carbapenem resistance. Twenty-one (8.3%) of 253 individuals had E. coli isolates with reduced quinolone susceptibility. All 21 isolates were positive for at least 1 qnr gene, with 3 (14.3%) isolates positive for qnrB, 5 (23.8%) positive for qnrS, and 13 (61.9%) positive for both qnrB and qnrS genes. All the enterococci isolates were vancomycin-susceptible. Higher susceptibility to the critically important antimicrobials was found in this study. This study can serve as a baseline for future antimicrobial resistance surveillance within this region.

  16. Fecal Indicator Bacteria and Environmental Observations: Validation of Virtual Beach

    EPA Science Inventory

    Contamination of recreational waters by fecal material is often assessed using indicator bacteria such as enterococci. Enumeration based on culturing methods can take up to 48 hours to complete, limiting the accuracy of water quality evaluations. Molecular microbial techniques em...

  17. Cleaning, resistant bacteria, and antibiotic prescribing in residential aged care facilities.

    PubMed

    Cowan, Raquel U; Kishan, Divya; Walton, Aaron L; Sneath, Emmy; Cheah, Thomas; Butwilowsky, Judith; Friedman, N Deborah

    2016-03-01

    Residents of residential aged care facilities (RACFs) are at risk of colonization and infection with multidrug-resistant bacteria, and antibiotic prescribing is often inappropriate and not based on culture-proven infection. We describe low levels of resident colonization and environmental contamination with resistant gram-negative bacteria in RACFs, but high levels of empirical antibiotic use not guided by microbiologic culture. This research highlights the importance of antimicrobial stewardship and environmental cleaning in aged care facilities. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  18. Vegetable Contamination by the Fecal Bacteria of Poultry Manure: Case Study of Gardening Sites in Southern Benin

    PubMed Central

    Atidégla, Séraphin C.; Huat, Joël; Agbossou, Euloge K.; Saint-Macary, Hervé; Glèlè Kakai, Romain

    2016-01-01

    A study was conducted in southern Benin to assess the contamination of vegetables by fecal coliforms, Escherichia coli, and fecal streptococci as one consequence of the intensification of vegetable cropping through fertilization with poultry manure. For this purpose, on-farm trials were conducted in 2009 and 2010 at Yodo-Condji and Ayi-Guinnou with three replications and four fertilization treatments including poultry manure and three vegetable crops (leafy eggplant, tomato, and carrot). Sampling, laboratory analyses, and counts of fecal bacteria in the samples were performed in different cropping seasons. Whatever the fertilization treatment, the logs of mean fecal bacteria count per g of fresh vegetables were variable but higher than AFNOR criteria. The counts ranged from 8 to 10 fecal coliforms, from 5 to 8 fecal streptococci, and from 2 to 6 Escherichia coli, whereas AFNOR criteria are, respectively, 0, 1, and 0. The long traditional use of poultry manure and its use during the study helped obtain this high population of fecal pathogens. Results confirmed that the contamination of vegetables by fecal bacteria is mainly due to the use of poultry manure. The use of properly composted poultry manure with innovative cropping techniques should help reduce the number and incidence of pathogens. PMID:27069914

  19. Antimicrobial resistance among Enterobacteriaceae in South America: history, current dissemination status and associated socioeconomic factors.

    PubMed

    Bonelli, Raquel Regina; Moreira, Beatriz Meurer; Picão, Renata Cristina

    2014-04-01

    South America exhibits some of the higher rates of antimicrobial resistance in Enterobactericeae worldwide. This continent includes 12 independent countries with huge socioeconomic differences, where the ample access to antimicrobials, including counterfeit ones, coexists with ineffective health systems and sanitation problems, favoring the emergence and dissemination of resistant strains. This work presents a literature review concerning the evolution and current status of antimicrobial resistance threats found among Enterobacteriaceae in South America. Resistance to β-lactams, fluoroquinolones and aminoglycosides was emphasized along with description of key epidemiological studies that highlight the success of specific resistance determinants in different parts of the continent. In addition, a discussion regarding political and socioeconomic factors possibly related to the dissemination of antimicrobial resistant strains in clinical settings and at the community is presented. Finally, in order to assess the possible sources of resistant bacteria, we compile the current knowledge about the occurrence of antimicrobial resistance in isolates in South American' food, food-producing animals and off-hospitals environments. By addressing that intensive intercontinental commerce and tourism neutralizes the protective effect of geographic barriers, we provide arguments reinforcing that globally integrated efforts are needed to decelerate the emergence and dissemination of antimicrobial resistant strains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Combination Approaches to Combat Multi-Drug Resistant Bacteria

    PubMed Central

    Worthington, Roberta J.; Melander, Christian

    2013-01-01

    The increasing prevalence of infections caused by multi-drug resistant bacteria is a global health problem that is exacerbated by the dearth of novel classes of antibiotics entering the clinic over the past 40 years. Herein we describe recent developments toward combination therapies for the treatment of multi-drug resistant bacterial infections. These efforts include antibiotic-antibiotic combinations, and the development of adjuvants that either directly target resistance mechanisms such as the inhibition of β-lactamase enzymes, or indirectly target resistance by interfering with bacterial signaling pathways such as two-component systems. We also discuss screening of libraries of previously approved drugs to identify non-obvious antimicrobial adjuvants. PMID:23333434

  1. Impact of colistin sulfate treatment of broilers on the presence of resistant bacteria and resistance genes in stored or composted manure.

    PubMed

    Le Devendec, Laetitia; Mourand, Gwenaelle; Bougeard, Stéphanie; Léaustic, Julien; Jouy, Eric; Keita, Alassane; Couet, William; Rousset, Nathalie; Kempf, Isabelle

    2016-10-15

    The application of manure may result in contamination of the environment with antimicrobials, antimicrobial-resistant bacteria, resistance genes and plasmids. The aim of this study was to investigate the impact of the administration of colistin and of manure management on (i) the presence of colistin-resistant Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa and (ii) the prevalence of various antimicrobial resistance genes in feces and in composted or stored manure. One flock of chickens was treated with colistin at the recommended dosage and a second flock was kept as an untreated control. Samples of feces, litter and stored or composted manure from both flocks were collected for isolation and determination of the colistin-susceptibility of E. coli, K. pneumoniae and P. aeruginosa and quantification of genes coding for resistance to different antimicrobials. The persistence of plasmids in stored or composted manure from colistin-treated broilers was also evaluated by plasmid capturing experiments. Results revealed that colistin administration to chickens had no apparent impact on the antimicrobial resistance of the dominant Enterobacteriaceae and P. aeruginosa populations in the chicken gut. Composting stimulated an apparently limited decrease in genes coding for resistance to different antimicrobial families. Importantly, it was shown that even after six weeks of composting or storage, plasmids carrying antimicrobial resistance genes could still be transferred to a recipient E. coli. In conclusion, composting is insufficient to completely eliminate the risk of spreading antimicrobial resistance through chicken manure. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. The role of vaccines in fighting antimicrobial resistance (AMR).

    PubMed

    Jansen, Kathrin U; Anderson, Annaliesa S

    2018-05-22

    The problem of antimicrobial resistance (AMR) and the associated morbidity and mortality due to antibiotic resistant bacterial pathogens is not new. However, AMR has been increasing at an alarming rate with appearances of diseases caused by bacteria exhibiting resistance to not just one but multiple classes of antibiotics. The World Health Organization (WHO) supported by governments, health ministries and health agencies has formulated global action plans to combat the rise in AMR, supporting a number of proven initiatives such as antimicrobial stewardship, investments in development of new classes of antibiotics, and educational programs designed to eliminate inappropriate antibiotic use. Vaccines as tools to reduce AMR have historically been under-recognized, yet the positive effect in reducing AMR has been well established. For example Haemophilus influenzae type B (Hib) as well as Streptococcus pneumoniae (pneumococcal) conjugate vaccines have impressive track records in not only preventing life threatening diseases caused by these bacteria, but also reducing antibiotic use and AMR. This paper will describe the drivers of antibiotic use and subsequent development of AMR; it will make the case how existing vaccines are already participating in combatting AMR, describe future prospects for the role of new vaccines in development to reduce AMR, and highlight challenges associated with future vaccine development to combat AMR.

  3. The impact of fecal sample processing on prevalence estimates for antibiotic-resistant Escherichia coli.

    PubMed

    Omulo, Sylvia; Lofgren, Eric T; Mugoh, Maina; Alando, Moshe; Obiya, Joshua; Kipyegon, Korir; Kikwai, Gilbert; Gumbi, Wilson; Kariuki, Samuel; Call, Douglas R

    2017-05-01

    Investigators often rely on studies of Escherichia coli to characterize the burden of antibiotic resistance in a clinical or community setting. To determine if prevalence estimates for antibiotic resistance are sensitive to sample handling and interpretive criteria, we collected presumptive E. coli isolates (24 or 95 per stool sample) from a community in an urban informal settlement in Kenya. Isolates were tested for susceptibility to nine antibiotics using agar breakpoint assays and results were analyzed using generalized linear mixed models. We observed a <3-fold difference between prevalence estimates based on freshly isolated bacteria when compared to isolates collected from unprocessed fecal samples or fecal slurries that had been stored at 4°C for up to 7days. No time-dependence was evident (P>0.1). Prevalence estimates did not differ for five distinct E. coli colony morphologies on MacConkey agar plates (P>0.2). Successive re-plating of samples for up to five consecutive days had little to no impact on prevalence estimates. Finally, culturing E. coli under different conditions (with 5% CO 2 or micro-aerobic) did not affect estimates of prevalence. For the conditions tested in these experiments, minor modifications in sample processing protocols are unlikely to bias estimates of the prevalence of antibiotic-resistance for fecal E. coli. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Oral antimicrobials increase antimicrobial resistance in porcine E. coli--a systematic review.

    PubMed

    Burow, E; Simoneit, C; Tenhagen, B-A; Käsbohrer, A

    2014-03-01

    Administration of antimicrobials to livestock increases the risk of antimicrobial resistance (AMR) in commensal bacteria. Antimicrobials in pig production are usually administered per pen via feed which implies treatment of sick alongside with healthy animals. The objective of this systematic literature review was to investigate the effect of orally administered antimicrobials on AMR in Escherichia coli of swine. Studies published in peer reviewed journals were retrieved from the international online databases ISI Web of Knowledge, PubMed, Scopus and the national electronic literature data base of Deutsches Institut für Medizinische Dokumentation und Information. The studies were assessed using the eligibility criteria English or German language, access to full paper version, defined treatment and control group (initial value or non-treatment) as well as administration and resistance testing of the same antimicrobial class. In the qualitative synthesis, only studies were included presenting the summary measures odds ratio or prevalence of resistance, the category of the applied antimicrobial and the dosage. An effect of the antimicrobial on AMR in E. coli was evaluated as an "increase", "no effect" or "decrease" if the odds or alternatively the prevalence ratio were >1.0, 1.0 or <1.0, respectively. Eleven studies, describing 36 different trials, fulfilled the eligibility criteria and were finally assessed. An increase of AMR in E. coli was found in 10 out of 11 trials comparing AMR after with AMR prior to oral treatment and in 22 of the 25 trials comparing orally treated with untreated groups. Effects expressed as odds or prevalence ratios were highest for the use of aminoglycosides, quinolones and tetracycline. There was no clear association between the reported dosage and AMR towards tetracycline. Information on antimicrobial substance and dosage was missing in 4 and 5 of the 11 finally selected studies. The 36 identified trials were inhomogenous in usage and

  5. Antimicrobial resistance in the respiratory microbiota of people with cystic fibrosis.

    PubMed

    Sherrard, Laura J; Tunney, Michael M; Elborn, J Stuart

    2014-08-23

    Cystic fibrosis is characterised by chronic polymicrobial infection and inflammation in the airways of patients. Antibiotic treatment regimens, targeting recognised pathogens, have substantially contributed to increased life expectancy of patients with this disease. Although the emergence of antimicrobial resistance and selection of highly antibiotic-resistant bacterial strains is of major concern, the clinical relevance in cystic fibrosis is yet to be defined. Resistance has been identified in recognised cystic fibrosis pathogens and in other bacteria (eg, Prevotella and Streptococcus spp) detected in the airway microbiota, but their role in the pathophysiology of infection and inflammation in chronic lung disease is unclear. Increased antibiotic resistance in cystic fibrosis might be attributed to a range of complex factors including horizontal gene transfer, hypoxia, and biofilm formation. Strategies to manage antimicrobial resistance consist of new antibiotics or localised delivery of antimicrobial agents, iron sequestration, inhibition of quorum-sensing, and resistome analysis. Determination of the contributions of every bacterial species to lung health or disease in cystic fibrosis might also have an important role in the management of antibiotic resistance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Antimicrobial stewardship: English Surveillance Programme for Antimicrobial Utilization and Resistance (ESPAUR).

    PubMed

    Ashiru-Oredope, Diane; Hopkins, Susan

    2013-11-01

    The clinical, public health and economic implications of antimicrobial resistance present a major threat to future healthcare. Antimicrobial use is a major driver of resistance, and antimicrobial stewardship programmes are increasingly being advocated as a means of improving the quality of prescribing. However, to increase their impact and assess their success, a better understanding of antimicrobial usage, both in primary and secondary care, and linkage with antimicrobial resistance data are required. In England, national summaries of primary care dispensing data are issued annually by the Health and Social Care Information Centre. However, there is currently no routine public reporting of antimicrobial usage in hospitals. In response to the threat posed by antimicrobial resistance, as highlighted in the Report of the Chief Medical Officer and on the request of the Department of Health, Public Health England has developed a new national programme, the English Surveillance Programme for Antimicrobial Utilization and Resistance (ESPAUR). The programme will bring together the elements of antimicrobial utilization and resistance surveillance in both primary and secondary care settings, alongside the development of quality measures and methods to monitor unintended outcomes of antimicrobial stewardship and both public and professional behaviour interventions. This article reports on the background to the programme development, the current oversight group membership and the public reporting structure.

  7. Current and novel antibiotics against resistant Gram-positive bacteria.

    PubMed

    Perez, Federico; Salata, Robert A; Bonomo, Robert A

    2008-01-01

    The challenge posed by resistance among Gram-positive bacteria, epitomized by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and vancomycin-intermediate and -resistant S. aureus (VISA and VRSA) is being met by a new generation of antimicrobials. This review focuses on the new β-lactams with activity against MRSA (ceftobiprole and ceftaroline) and on the new glycopeptides (oritavancin, dalbavancin, and telavancin). It will also consider the role of vancomycin in an era of existing alternatives such as linezolid, daptomycin and tigecycline. Finally, compounds in early development are described, such as iclaprim, friulimicin, and retapamulin, among others.

  8. Triple-acting antimicrobial treatment for drug-resistant and intracellular Staphylococcus aureus

    USDA-ARS?s Scientific Manuscript database

    Multi-drug resistant bacteria are a persistent problem in modern health care, food safety and animal health. There is a need for new antimicrobials to replace over-used conventional antibiotics. Staphylococcus aureus (S. aureus) is a notorious pathogen for both animal and human health with multi-d...

  9. Triple-acting antimicrobial treatment for drug-resistant and intracellular Staphylococcus aureus.

    USDA-ARS?s Scientific Manuscript database

    Multi-drug resistant bacteria are a persistent problem in modern health care, food safety and animal health. There is a need for new antimicrobials to replace over-used conventional antibiotics. Staphylococcus aureus (S. aureus) is a notorious pathogen for both animal and human health with multi-d...

  10. Herd-level association between antimicrobial use and antimicrobial resistance in bovine mastitis Staphylococcus aureus isolates on Canadian dairy farms.

    PubMed

    Saini, V; McClure, J T; Scholl, D T; DeVries, T J; Barkema, H W

    2012-04-01

    Surveillance of antimicrobial use and resistance is needed to manage antimicrobial resistance in bacteria. In this study, data were collected on antimicrobial use and resistance in Staphylococcus aureus (n=562), isolated from intramammary infections and (sub)clinical mastitis cases on 89 dairy farms in 4 regions of Canada [Alberta, Ontario, Québec, and the Maritime Provinces (Prince Edward Island, Nova Scotia, and New Brunswick)]. Dairy producers were asked to deposit empty drug containers into specially provided receptacles, and antimicrobial drug use rate was calculated to quantify antimicrobial use. Minimum inhibitory concentrations were determined using the Sensititer bovine mastitis plate system (TREK Diagnostic Systems Inc., Cleveland, OH), containing antimicrobials commonly used for mastitis treatment and control. Multivariable logistic regression models were built to determine herd-level risk factors of penicillin, ampicillin, pirlimycin, penicillin-novobiocin combination, tetracycline and sulfadimethoxine resistance in Staph. aureus isolates. Intramammary administration of the penicillin-novobiocin combination for dry cow therapy was associated with penicillin and ampicillin resistance [odds ratio (OR): 2.17 and 3.10, respectively]. Systemic administration of penicillin was associated with penicillin resistance (OR: 1.63). Intramammary administration of pirlimycin for lactating cow mastitis treatment was associated with pirlimycin resistance as well (OR: 2.07). Average herd parity was associated with ampicillin and tetracycline resistance (OR: 3.88 and 0.02, respectively). Average herd size was also associated with tetracycline resistance (OR: 1.02). Dairy herds in the Maritime region had higher odds of penicillin and lower odds of ampicillin resistance than dairy herds in Québec (OR: 2.18 and 0.19, respectively). Alberta dairy herds had lower odds of ampicillin and sulfadimethoxine resistance than dairy herds in Québec (OR: 0.04 and 0.08, respectively

  11. Resistance to Antibiotics of Clinical Relevance in the Fecal Microbiota of Mexican Wildlife

    PubMed Central

    Cristóbal-Azkarate, Jurgi; Dunn, Jacob C.; Day, Jennifer M. W.; Amábile-Cuevas, Carlos F.

    2014-01-01

    There are a growing number of reports of antibiotic resistance (ATBR) in bacteria living in wildlife. This is a cause for concern as ATBR in wildlife represents a potential public health threat. However, little is known about the factors that might determine the presence, abundance and dispersion of ATBR bacteria in wildlife. Here, we used culture and molecular methods to assess ATBR in bacteria in fecal samples from howler monkeys (Alouatta palliata), spider monkeys (Ateles geoffroyi), tapirs (Tapirus bairdii) and felids (jaguars, Panthera onca; pumas, Puma concolor; jaguarundis, Puma yagouaroundi; and ocelots, Leopardus pardalis) living freely in two regions of the Mexican state of Veracruz under different degrees of human influence. Overall, our study shows that ATBR is commonplace in bacteria isolated from wildlife in southeast Mexico. Most of the resistances were towards old and naturally occurring antibiotics, but we also observed resistances of potential clinical significance. We found that proximity to humans positively affected the presence of ATBR and that ATBR was higher in terrestrial than arboreal species. We also found evidence suggesting different terrestrial and aerial routes for the transmission of ATBR between humans and wildlife. The prevalence and potential ATBR transfer mechanisms between humans and wildlife observed in this study highlight the need for further studies to identify the factors that might determine ATBR presence, abundance and distribution. PMID:25233089

  12. Antimicrobial Resistance among Campylobacter Strains, United States, 1997–2001

    PubMed Central

    Nelson, Jennifer M.; Barrett, Timothy J.; Tauxe, Robert V.; Rossiter, Shannon P.; Friedman, Cindy R.; Joyce, Kevin W.; Smith, Kirk E.; Jones, Timothy F.; Hawkins, Marguerite A.; Shiferaw, Beletshachew; Beebe, James L.; Vugia, Duc J.; Rabatsky-Ehr, Terry; Benson, James A.; Root, Timothy P.; Angulo, Frederick J.

    2004-01-01

    We summarize antimicrobial resistance surveillance data in human and chicken isolates of Campylobacter. Isolates were from a sentinel county study from 1989 through 1990 and from nine state health departments participating in National Antimicrobial Resistance Monitoring System for enteric bacteria (NARMS) from 1997 through 2001. None of the 297 C. jejuni or C. coli isolates tested from 1989 through 1990 was ciprofloxacin-resistant. From 1997 through 2001, a total of 1,553 human Campylobacter isolates were characterized: 1,471 (95%) were C. jejuni, 63 (4%) were C. coli, and 19 (1%) were other Campylobacter species. The prevalence of ciprofloxacin-resistant Campylobacter was 13% (28 of 217) in 1997 and 19% (75 of 384) in 2001; erythromycin resistance was 2% (4 of 217) in 1997 and 2% (8 of 384) in 2001. Ciprofloxacin-resistant Campylobacter was isolated from 10% of 180 chicken products purchased from grocery stores in three states in 1999. Ciprofloxacin resistance has emerged among Campylobacter since 1990 and has increased in prevalence since 1997. PMID:15207064

  13. A novel cysteine-free venom peptide with strong antimicrobial activity against antibiotics-resistant pathogens from the scorpion Opistophthalmus glabrifrons.

    PubMed

    Bao, Aorigele; Zhong, Jie; Zeng, Xian-Chun; Nie, Yao; Zhang, Lei; Peng, Zhao Feng

    2015-10-01

    Antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus, pose serious threat to human health. The outbreak of antibiotic-resistant pathogens in recent years emphasizes once again the urgent need for the development of new antimicrobial agents. Here, we discovered a novel antimicrobial peptide from the scorpion Opistophthalmus glabrifrons, which was referred to as Opisin. Opisin consists of 19 amino acid residues without disulfide bridges. It is a cationic, amphipathic, and α-helical molecule. Protein sequence homology search revealed that Opisin shares 42.1-5.3% sequence identities to the 17/18-mer antimicrobial peptides from scorpions. Antimicrobial assay showed that Opisin is able to potently inhibit the growth of the tested Gram-positive bacteria with the minimal inhibitory concentration (MIC) values of 4.0-10.0 μM; in contrast, it possesses much lower activity against the tested Gram-negative bacteria and a fungus. It is interesting to see that Opisin is able to strongly inhibit the growth of methicillin- and vancomycin-resistant pathogens with the MICs ranging from 2.0 to 4.0 μM and from 4.0 to 6.0 μM, respectively. We found that at a concentration of 5 × MIC, Opisin completely killed all the cultured methicillin-resistant Staphylococcus aureus. These results suggest that Opisin is a promising therapeutic candidate for the treatment of the antibiotic-resistant bacterial infections. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

  14. Fecal-indicator bacteria in the Allegheny, Monongahela, and Ohio Rivers and selected tributaries, Allegheny County, Pennsylvania, 2001-2005

    USGS Publications Warehouse

    Buckwalter, Theodore F.; Zimmerman, Tammy M.; Fulton, John W.

    2006-01-01

    Concentrations of fecal-indicator bacteria were determined in 1,027 water-quality samples collected from July 2001 through August 2005 during dry- (72-hour dry antecedent period) and wet-weather (48-hour dry antecedent period and at least 0.3 inch of rain in a 24-hour period) conditions in the Allegheny, Monongahela, and Ohio Rivers (locally referred to as the Three Rivers) and selected tributaries in Allegheny County. Samples were collected at five sampling sites on the Three Rivers and at eight sites on four tributaries to the Three Rivers having combined sewer overflows. Water samples were analyzed for three fecal-indicator organisms fecal coliform, Escherichia coli (E. coli), and enterococci bacteria. Left-bank and right-bank surface-water samples were collected in addition to a cross-section composite sample at each site. Concentrations of fecal coliform, E. coli, and enterococci were detected in 98.6, 98.5, and 87.7 percent of all samples, respectively. The maximum fecal-indicator bacteria concentrations were collected from Sawmill Run, a tributary to the Ohio River; Sawmill Run at Duquesne Heights had concentrations of fecal coliform, E. coli, and enterococci of 410,000, 510,000, and 180,000 col/100 mL, respectively, following a large storm. The samples collected in the Three Rivers and selected tributaries frequently exceeded established recreational standards and criteria for bacteria. Concentrations of fecal coliform exceeded the Pennsylvania water-quality standard (200 col/100 mL) in approximately 63 percent of the samples. Sample concentrations of E. coli and enterococci exceeded the U.S. Environmental Protection Agency (USEPA) water-quality criteria (235 and 61 col/100 mL, respectively) in about 53 and 47 percent, respectively, of the samples. Fecal-indicator bacteria were most strongly correlated with streamflow, specific conductance, and turbidity. These correlations most frequently were observed in samples collected from tributary sites. Fecal

  15. [Potential antimicrobial drug interactions in clinical practice: consequences of polypharmacy and multidrug resistance].

    PubMed

    Martínez-Múgica, Cristina

    2015-12-01

    Polypharmacy is a growing problem nowadays, which can increase the risk of potential drug interactions, and result in a loss of effectiveness. This is particularly relevant to the anti-infective therapy, especially when infection is produced by resistant bacteria, because therapeutic options are limited and interactions can cause treatment failure. All antimicrobial prescriptions were retrospectively reviewed during a week in the Pharmacy Department, in order to detect potential drug-interactions and analysing their clinical significance. A total of 314 antimicrobial prescriptions from 151 patients were checked. There was at least one potential interaction detected in 40% of patients, being more frequent and severe in those infected with multidrug-resistant microorganisms. Drugs most commonly involved were quinolones, azoles, linezolid and vancomycin. Potential drug interactions with antimicrobial agents are a frequent problem that can result in a loss of effectiveness. This is why they should be detected and avoided when possible, in order to optimize antimicrobial therapy, especially in case of multidrug resistant infections.

  16. Antimicrobial use: Alternatives

    USDA-ARS?s Scientific Manuscript database

    For over fifty years, antimicrobials have been used in food animal production to maintain animal health and to increase productivity. The resulting increase in antimicrobial resistance among enteric bacteria has created two principal concerns: 1) the prevalence of drug-resistant pathogens leaves th...

  17. Use of a predictive protocol to measure the antimicrobial resistance risks associated with biocidal product usage.

    PubMed

    Wesgate, Rebecca; Grasha, Pierre; Maillard, Jean-Yves

    2016-04-01

    In this study we assessed the propensity of biocide exposure in the development of antimicrobial resistance in bacteria. Our protocol is based on reporting changes in established antimicrobial susceptibility profiles in biocides and antibiotics after during use exposure to a product. The during use exposure reflects worse conditions of product use during application. It differs from the term low concentration, which usually reflects a concentration below the minimal inhibitory concentration, but not necessarily a concentration that occurs in practice. Our results showed that exposure to triclosan (0.0004%) was associated with a high risk of developing resistance and cross-resistance in Staphylococcus aureus and Escherichia coli. This was not observed with exposure to chlorhexidine (0.00005%) or a hydrogen peroxide-based biocidal product (in during use conditions). Interestingly, exposure to a low concentration of hydrogen peroxide (0.001%) carried a risk of emerging resistance to antibiotics if the presence of the oxidizing agent was maintained. We observed a number of unstable clinical resistances to antibiotics after exposure to the cationic biocide and oxidizing agent, notably to tobramycin and ticarcillin-clavulanic acid. Using a decision tree based on the change in antimicrobial susceptibility test results, we were able to provide information on the effect of biocide exposure on the development of bacterial resistance to antimicrobials. Such information should address the call from the U.S. Food and Drug Administration and European Union Biocidal Products Regulation for manufacturers to provide information on antimicrobial resistance and cross-resistance in bacteria after the use of their product. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  18. Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content.

    PubMed

    Lee, Do Kyung; Jang, Seok; Baek, Eun Hye; Kim, Mi Jin; Lee, Kyung Soon; Shin, Hea Soon; Chung, Myung Jun; Kim, Jin Eung; Lee, Kang Oh; Ha, Nam Joo

    2009-06-11

    Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. In vitro culture experiments were performed to evaluate the ability of Bifidobacterium spp. isolated from healthy Koreans (20 approximately 30 years old) to reduce cholesterol-levels in MRS broth containing polyoxyethanylcholesterol sebacate. Animal experiments were performed to investigate the effects on lowering cholesterol, inhibiting harmful enzyme activities, and controlling fecal water content. For animal studies, 0.2 ml of the selected strain cultures (108 approximately 109 CFU/ml) were orally administered to SD rats (fed a high-cholesterol diet) every day for 2 weeks. B. longum SPM1207 reduced serum total cholesterol and LDL levels significantly (p < 0.05), and slightly increased serum HDL. B. longum SPM1207 also increased fecal LAB levels and fecal water content, and reduced body weight and harmful intestinal enzyme activities. Daily consumption of B. longum SPM1207 can help in managing mild to moderate hypercholesterolemia, with potential to improve human health by helping to prevent colon cancer and constipation.

  19. The Three Bacterial Lines of Defense against Antimicrobial Agents.

    PubMed

    Zhou, Gang; Shi, Qing-Shan; Huang, Xiao-Mo; Xie, Xiao-Bao

    2015-09-09

    Antimicrobial agents target a range of extra- and/or intracellular loci from cytoplasmic wall to membrane, intracellular enzymes and genetic materials. Meanwhile, many resistance mechanisms employed by bacteria to counter antimicrobial agents have been found and reported in the past decades. Based on their spatially distinct sites of action and distribution of location, antimicrobial resistance mechanisms of bacteria were categorized into three groups, coined the three lines of bacterial defense in this review. The first line of defense is biofilms, which can be formed by most bacteria to overcome the action of antimicrobial agents. In addition, some other bacteria employ the second line of defense, the cell wall, cell membrane, and encased efflux pumps. When antimicrobial agents permeate the first two lines of defense and finally reach the cytoplasm, many bacteria will make use of the third line of defense, including alterations of intracellular materials and gene regulation to protect themselves from harm by bactericides. The presented three lines of defense theory will help us to understand the bacterial resistance mechanisms against antimicrobial agents and design efficient strategies to overcome these resistances.

  20. Escherichia coli and fecal-coliform bacteria as indicators of recreational water quality

    USGS Publications Warehouse

    Francy, D.S.; Myers, Donna N.; Metzker, K.D.

    1993-01-01

    In 1986, the U.S. Environmental Protection Agency (USEPA) recommended that Escherichia coli (E. coli) be used in place of fecal-coliform bacteria in State recreational water-quality standards as an indicator of fecal contamination. This announcement followed an epidemiological study in which E. coli concentration was shown to be a better predictor of swimming-associated gastrointestinal illness than fecal-coliform concentration. Water-resource managers from Ohio have decided to collect information specific to their waters and decide whether to use E. coli or fecal-coliform bacteria as the basis for State recreational water-quality standards. If one indicator is a better predictor of recreational water quality than the other and if the relation between the two indicators is variable, then the indicator providing the most accurate measure of recreational water quality should be used in water-quality standards. Water-quality studies of the variability of concentrations of E. coli to fecal-coliform bacteria have shown that (1) concentrations of the two indicators are positively correlated, (2) E. coli to fecal-coliform ratios differ considerably from site to site, and (3) the E. coli criteria recommended by USEPA may be more difficult to meet than current (1992) fecal-coliform standards. In this study, a statistical analysis was done on concentrations of E. coli and fecal-coliform bacteria in water samples collected by two government agencies in Ohio-- the U.S. Geological Survey (USGS) and the Ohio River Valley Water Sanitation Commission (ORSANCO). Data were organized initially into five data sets for statistical analysis: (1) Cuyahoga River, (2) Olentangy River, (3) Scioto River, (4) Ohio River at Anderson Ferry, and (5) Ohio River at Cincinnati Water Works and Tanners Creek. The USGS collected the data in sets 1, 2, and 3, whereas ORSANCO collected the data in sets 4 and 5. The relation of E. coli to fecal-coliform concentration was investigated by use of linear

  1. Comparative Analysis of the Antimicrobial Activities of Plant Defensin-Like and Ultrashort Peptides against Food-Spoiling Bacteria.

    PubMed

    Kraszewska, Joanna; Beckett, Michael C; James, Tharappel C; Bond, Ursula

    2016-07-15

    Antimicrobial peptides offer potential as novel therapeutics to combat food spoilage and poisoning caused by pathogenic and nonpathogenic bacteria. Our previous studies identified the peptide human beta-defensin 3 (HBD3) as a potent antimicrobial agent against a wide range of beer-spoiling bacteria. Thus, HBD3 is an excellent candidate for development as an additive to prevent food and beverage spoilage. To expand the repertoire of peptides with antimicrobial activity against bacteria associated with food spoilage and/or food poisoning, we carried out an in silico discovery pipeline to identify peptides with structure and activity similar to those of HBD3, focusing on peptides of plant origin. Using a standardized assay, we compared the antimicrobial activities of nine defensin-like plant peptides to the activity of HBD3. Only two of the peptides, fabatin-2 and Cp-thionin-2, displayed antimicrobial activity; however, the peptides differed from HBD3 in being sensitive to salt and were thermostable. We also compared the activities of several ultrashort peptides to that of HBD3. One of the peptides, the synthetic tetrapeptide O3TR, displayed biphasic antimicrobial activity but had a narrower host range than HBD3. Finally, to determine if the peptides might act in concert to improve antimicrobial activity, we compared the activities of the peptides in pairwise combinations. The plant defensin-like peptides fabatin-2 and Cp-thionin-2 displayed a synergistic effect with HBD3, while O3TR was antagonistic. Thus, some plant defensin-like peptides are effective antimicrobials and may act in concert with HBD3 to control bacteria associated with food spoilage and food poisoning. Food spoilage and food poisoning caused by bacteria can have major health and economic implications for human society. With the rise in resistance to conventional antibiotics, there is a need to identify new antimicrobials to combat these outbreaks in our food supply. Here we screened plant peptide

  2. Fecal-indicator bacteria concentrations in the Illinois River between Hennepin and Peoria, Illinois: 2007-08

    USGS Publications Warehouse

    Dupre, David H.; Hortness, Jon E.; Terrio, Paul J.; Sharpe, Jennifer B.

    2012-01-01

    The Illinois Environmental Protection Agency has designated portions of the Illinois River in Peoria, Woodford, and Tazewell Counties, Illinois, as impaired owing to the presence of fecal coliform bacteria. The U.S. Geological Survey, in cooperation with the Tri-County Regional Planning Commission, examined the water quality in the Illinois River and major tributaries within a 47-mile reach between Peoria and Hennepin, Ill., during water year 2008 (October 2007–September 2008). Investigations included synoptic (snapshot) sampling at multiple locations in a 1-day period: once in October 2007 during lower streamflow conditions, and again in June 2008 during higher streamflow conditions. Five locations in the study area were monitored for the entire year at monthly or more frequent intervals. Two indicator bacteria were analyzed in each water sample: fecal coliform and Escherichia coli (E. coli). Streamflow information from previously established monitoring locations in the study area was used in the analysis. Correlation analyses were used to characterize the relation between the two fecal-indicator bacteria and the relation of either indicator to streamflow. Concentrations of the two measured fecal-indicator bacteria correlated well for all samples analyzed (r = 0.94, p E. coli: rho = -0.43, p = 0.0157). The correlation between fecal indicators and streamflow in tributaries or in the Illinois River at Hennepin was found to be statistically significant, yet moderate in strength with coefficient values ranging from r = 0.4 to 0.6. Indirect observations from the June 2008 higher flow synoptic event may indicate continued effects from combined storm and sanitary sewers in the vicinity of the Illinois River near Peoria, Ill., contributing to observed single-sample exceedance of the State criterion for fecal coliform.

  3. Multidrug-resistant organisms, wounds and topical antimicrobial protection.

    PubMed

    Bowler, Philip G; Welsby, Sarah; Towers, Victoria; Booth, Rebecca; Hogarth, Andrea; Rowlands, Victoria; Joseph, Alexis; Jones, Samantha A

    2012-08-01

    Multidrug-resistant organisms (MDROs) are increasingly implicated in both acute and chronic wound infections. The limited therapeutic options are further compromised by the fact that wound bacteria often co-exist within a biofilm community which enhances bacterial tolerance to antibiotics. As a consequence, topical antiseptics may be an important consideration for minimising the opportunity for wound infections involving MDROs. The objective of this research was to investigate the antimicrobial activity of a silver-containing gelling fibre dressing against a variety of MDROs in free-living and biofilm states, using stringent in vitro models designed to simulate a variety of wound conditions. MDROs included Acinetobacter baumannii, community-associated methicillin-resistant Staphylococcus aureus, and extended-spectrum beta-lactamase-producing bacteria. Clostridium difficile was also included in the study because it carries many of the characteristics seen in MDROs and evidence of multidrug resistance is emerging. Sustained in vitro antimicrobial activity of the silver-containing dressing was shown against 10 MDROs in a simulated wound fluid over 7 days, and inhibitory and bactericidal effects against both free-living and biofilm phenotypes were also consistently shown in simulated colonised wound surface models. The in vitro data support consideration of the silver-containing gelling fibre dressing as part of a protocol of care in the management of wounds colonised or infected with MDROs. © 2012 The Authors. International Wound Journal © 2012 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

  4. A novel combination approach of human polyclonal IVIG and antibiotics against multidrug-resistant Gram-positive bacteria

    PubMed Central

    Sallam, Mariam Madkour; Abou-Aisha, Khaled; El-Azizi, Mohamed

    2016-01-01

    Background Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA) and enterococci, have shown a remarkable ability to develop resistance to antimicrobial agents. Objective We aimed to assess possible enhancement of the antimicrobial activity of vancomycin, amoxicillin, clarithromycin, and azithromycin by human polyclonal intravenous immunoglobulin G (IVIG) against 34 multidrug-resistant (MDR) bacterial isolates, including MRSA, Enterococcus faecium, and Enterococcus faecalis. Materials and methods Double combinations of the antibiotics with the IVIG were assessed by checkerboard assay, where the interaction was evaluated with respect to the minimum inhibitory concentration (MIC) of the antibiotics. The results of the checkerboard assay were verified in vitro using time-kill assay and in vivo using an invasive sepsis murine model. Results The checkerboard assay showed that IVIG enhanced the antimicrobial activity of amoxicillin and clarithromycin against isolates from the three groups of bacteria, which were resistant to the same antibiotics when tested in the absence of IVIG. The efficacy of vancomycin against 15% of the tested isolates was enhanced when it was combined with the antibodies. Antagonism was demonstrated in 47% of the E. faecalis isolates when clarithromycin was combined with the IVIG. Synergism was proved in the time-kill assay when amoxicillin was combined with the antibodies; meanwhile, antagonism was not demonstrated in all tested combinations, even in combinations that showed such response in checkerboard assay. Conclusion The suggested approach is promising and could be helpful to enhance the antimicrobial activity of not only effective antibiotics but also antibiotics that have been proven to be ineffective against MDR bacteria. To our knowledge, this combinatorial approach against MDR bacteria, such as MRSA and enterococci, has not been investigated before. PMID:27994476

  5. Temporal variations in patterns of Escherichia coli strain diversity and antimicrobial resistance in the migrant Egyptian vulture

    PubMed Central

    Maherchandani, Sunil; Shringi, B. N.; Kashyap, Sudhir Kumar

    2018-01-01

    ABSTRACT Aims: Multiple antimicrobial resistance in Escherichia coli of wild vertebrates is a global concern with scarce assessments on the subject from developing countries that have high human-wild species interactions. We studied the ecology of E. coli in a wintering population of Egyptian Vultures in India to understand temporal changes in both E. coli strains and patterns of antimicrobial resistance. Methods and Results: We ribotyped E. coli strains and assessed antimicrobial resistance from wintering vultures at a highly synanthropic carcass dump in north-west India. Both E. coli occurence (90.32%) and resistance to multiple antimicrobials (71.43%) were very high. Clear temporal patterns were apparent. Diversity of strains changed and homogenized at the end of the Vultures’ wintering period, while the resistance pattern showed significantly difference inter-annually, as well as between arrival and departing individuals within a wintering cycle. Significance of study: The carcass dump environment altered both E. coli strains and multiple antimicrobial resistance in migratory Egyptian Vultures within a season. Long-distance migratory species could therefore disseminate resistant E. coli strains across broad geographical scales rendering regional mitigation strategies to control multiple antimicrobial resistance in bacteria ineffective. PMID:29755700

  6. Antimicrobial Resistance in Escherichia coli Recovered from Feedlot Cattle and Associations with Antimicrobial Use

    PubMed Central

    Benedict, Katharine M.; Gow, Sheryl P.; McAllister, Tim A.; Booker, Calvin W.; Hannon, Sherry J.; Checkley, Sylvia L.; Noyes, Noelle R.; Morley, Paul S.

    2015-01-01

    The objectives of this study were to estimate the prevalence of antimicrobial resistance (AMR) and to investigate the associations between exposures to antimicrobial drugs (AMDs) and AMR in fecal non-type specific Escherichia coli (NTSEC) recovered from a large population of feedlot cattle. Two-stage random sampling was used to select individually identified cattle for enrollment, which were sampled at arrival and then a second time later in the feeding period. Advanced regression techniques were used to estimate resistance prevalences, and to investigate associations between AMD exposures in enrolled cattle and penmates and AMR identified in NTSEC recovered from the second sample set. Resistance was most commonly detected to tetracycline, streptomycin, and sulfisoxazole, and was rarely identified for critically important AMDs. All cattle were exposed to AMDs in feed, and 45% were treated parenterally. While resistance prevalence generally increased during the feeding period, most AMD exposures were not significantly associated with AMR outcomes. Exposures of enrolled cattle to tetracycline were associated with increased resistance to tetracycline and trimethoprim sulfa, while beta-lactam exposures were associated with decreased likelihood of detecting streptomycin resistance. Pen-level AMD exposure measures were not associated with resistance outcomes. These findings suggest that tetracycline treatment of feedlot cattle can be associated with modest increases in risk for recovery of resistant NTSEC, but the numerous treatments with an advanced macrolide (tulathromycin) were not associated with detectable increases in resistance in NTSEC. All cattle were exposed to in-feed treatments of tetracycline and this could limit the ability to identify the full impact of these exposures, but these exposures varied for enrolled cattle varied, providing an opportunity to evaluate a dose response. While AMD exposures were not associated with detectably increased risks for

  7. Free-living Canada geese and antimicrobial resistance.

    PubMed

    Cole, Dana; Drum, David J V; Stalknecht, David E; White, David G; Lee, Margie D; Ayers, Sherry; Sobsey, Mark; Maurer, John J

    2005-06-01

    We describe antimicrobial resistance among Escherichia coli isolated from free-living Canada Geese in Georgia and North Carolina (USA). Resistance patterns are compared to those reported by the National Antimicrobial Resistance Monitoring System. Canada Geese may be vectors of antimicrobial resistance and resistance genes in agricultural environments.

  8. Modeling Fate and Transport of Fecal Coliform Bacteria Using SWAT 2005 (Case Study: Jajrood River Watershed, Iran)

    NASA Astrophysics Data System (ADS)

    Maghrebi, M.; Tajrishy, M.

    2010-12-01

    Jajrood River watershed is one of the main drinking water resources of the capital city of Tehran, Iran. In addition it has been available as many recreational usages especially in the warm months. As a result of being located near one of the crowded cities of the world, a variety of microbial pollutions is commonly perceived in the Jajrood River. Among them, there are strong concerns about fecal coliform bacteria concentration. This article aimed to model fate and transport of fecal coliform bacteria in Jajrood River watershed using Soil and Water Assessment Tool (SWAT) model version 2005. Potential pollutant sources in the study area were detected and quantified for modeling purposes. In spite of being lack of knowledge about bacteria die-off rate in small river bodies, as well as in other watershed-based forms, fecal coliform bacteria die-off rates were estimated using both laboratory and field data investigations with some simplifications. The SWAT model was calibrated over an extended time period (1997-2002) for this watershed. The river flow calibrated using SUFI-2 software and resulted in a very good outputs (R2=0.82, E=0.81). Furthermore SWAT model was validated over January 2003 to September 2005 in the study area and has resulted in good outputs (R2=0.61, E=0.57). This research illustrates SWAT 2005 capability to model fecal coliform bacteria in a populated watershed, and deals with most of watershed microbial pollution sources that are usually observed in developing countries. Fecal coliform concentration simulation results were mostly in the same order in comparison with real data. However, Differences were judged to be related to lack of input data. In this article different aspects of SWAT capabilities for modeling of fecal coliform bacteria concentration will be reviewed and it will present new insights in bacteria modeling procedures especially for mountainous, high populated and small sized watersheds.

  9. The 2008 Garrod Lecture: antimicrobial resistance--animals and the environment.

    PubMed

    2008-08-01

    The evolution of resistance to microbes is one of the most significant problems in modern medicine, posing serious threats to human and animal health. The early work on the use of antibiotics to bacterial infections gave much hope that infectious diseases were no longer a problem, especially in the human field. However, as their use, indeed over-use, progressed, resistance (both monoresistance and multiresistance), which was often transferable between different strains and species of bacteria, emerged. In addition, the situation is increasingly complex, as various mechanisms of resistance, including a wide range of beta-lactamases, are now complicating the issue. The use of antibiotics in animals, especially those used for growth promotion, has come in for serious criticism, especially those where their use should be reserved for difficult human infections. To lend control, certain antibiotic growth promoters have been banned from use in the EU and the UK. Antimicrobial resistance is not confined to bacteria but occurs in viruses, protozoa and helminths. In many of these, the mechanism of resistance is unknown, and hence their control is still in question. It is likely, however, that the mechanisms are no less complicated than those pertaining to bacteria.

  10. Comparison of fecal indicators with pathogenic bacteria and rotavirus in groundwater

    PubMed Central

    Ferguson, Andrew S.; Layton, Alice C.; Mailloux, Brian J; Culligan, Patricia J.; Williams, Daniel E.; Smartt, Abby E.; Sayler, Gary S.; Feighery, John; McKay, Larry; Knappett, Peter S.K.; Alexandrova, Ekaterina; Arbit, Talia; Emch, Michael; Escamilla, Veronica; Ahmed, Kazi Matin; Alam, Md. Jahangir; Streatfield, P. Kim; Yunus, Mohammad; van Geen, Alexander

    2012-01-01

    Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary. PMID:22705866

  11. Antimicrobial resistance and production of toxins in Escherichia coli strains from wild ruminants and the alpine marmot.

    PubMed

    Caprioli, A; Donelli, G; Falbo, V; Passi, C; Pagano, A; Mantovani, A

    1991-04-01

    Escherichia coli strains isolated from 81 fecal samples from red deer (Cervus elaphus), roe deer (Capreoulus capreoulus), chamois (Rupicapra rupicapra) and alpine marmot (Marmota marmota) living in the Stelvio National Park, Italy, were examined for antimicrobial resistance and production of toxic factors. Direct plating of specimens on media containing antimicrobial drugs allowed us to isolate resistant strains of E. coli from 10 of 59 (17%) specimens examined by this technique. Nine of 31 specimens from red deer (29%) contained resistant strains. Different animals were likely colonized by the same resistant strain of E. coli. Conjugative R plasmids were found in four strains isolated from the marmot, roe deer and chamois. A strain from red deer produced heat-stable enterotoxin and another strain produced both hemolysin and cytotoxic necrotizing factor. A marmot isolate produced hemolysin alone. No strains were found to produce heat-labile enterotoxin or verotoxins.

  12. Epidemiology, ecology, and molecular genetics of antimicrobial resistance in pathogenic and commensal bacteria from food animals

    USDA-ARS?s Scientific Manuscript database

    The National Antimicrobial Resistance Monitoring System (NARMS) is a collaborative program between the Food and Drug Administration (FDA), the Centers for Disease Control (CDC), and the United States Department of Agriculture to prospectively monitor changes in antimicrobial susceptibilities of zoon...

  13. Identification of antibiotic resistant bacteria community and a GeoChip based study of resistome in urban watersheds.

    PubMed

    Low, Adrian; Ng, Charmaine; He, Jianzhong

    2016-12-01

    Urban watersheds from point sources are potential reservoirs of antibiotic resistance genes (ARGs). However, few studies have investigated urban watersheds of non-point sources. To understand the type of ARGs and bacteria that might carry such genes, we investigated two non-point source urban watersheds with different land-use profiles. Antibiotic resistance levels of two watersheds (R1, R3) were examined using heterotrophic plate counts (HPC) as a culturing method to obtain counts of bacteria resistant to seven antibiotics belonging to different classes (erythromycin, kanamycin, lincomycin, norfloxacin, sulfanilamide, tetracycline and trimethoprim). From the HPC study, 239 antibiotic resistant bacteria were characterized for resistance to more antibiotics. Furthermore, ARGs and antimicrobial biosynthesis genes were identified using GeoChip version 5.0 to elucidate the resistomes of surface waters in watersheds R1 and R3. The HPC study showed that water samples from R1 had significantly higher counts of bacteria resistant to erythromycin, kanamycin, norfloxacin, sulfanilamide, tetracycline and trimethoprim than those from R3 (Analysis of Similarity (ANOSIM), R = 0.557, p < 0.01). Of the seven antibiotics tested, lincomycin and trimethoprim resistant bacteria are greater in abundances. The 239 antibiotic resistant isolates represent a subset of resistant bacterial populations, including bacteria not previously known for resistance. Majority of the isolates had resistance to ampicillin, vancomycin, lincomycin and trimethoprim. GeoChip revealed similar ARGs in both watersheds, but with significantly higher intensities for tetX and β-lactamase B genes in R1 than R3. The genes with the highest average normalized intensities in R1 and R3 were tetracycline (tet) and fosfomycin (fosA) resistance genes, respectively. The higher abundance of tetX genes in R1 is congruent with the higher abundance of tetracycline resistant HPC observed in R1 samples. Strong correlations

  14. Comparison of methods to detect the in vitro activity of silver nanoparticles (AgNP) against multidrug resistant bacteria.

    PubMed

    Cavassin, Emerson Danguy; de Figueiredo, Luiz Francisco Poli; Otoch, José Pinhata; Seckler, Marcelo Martins; de Oliveira, Roberto Angelo; Franco, Fabiane Fantinelli; Marangoni, Valeria Spolon; Zucolotto, Valtencir; Levin, Anna Sara Shafferman; Costa, Silvia Figueiredo

    2015-10-05

    Multidrug resistant microorganisms are a growing challenge and new substances that can be useful to treat infections due to these microorganisms are needed. Silver nanoparticle may be a future option for treatment of these infections, however, the methods described in vitro to evaluate the inhibitory effect are controversial. This study evaluated the in vitro activity of silver nanoparticles against 36 susceptible and 54 multidrug resistant Gram-positive and Gram-negative bacteria from clinical sources. The multidrug resistant bacteria were oxacilin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp., carbapenem- and polymyxin B-resistant A. baumannii, carbapenem-resistant P. aeruginosa and carbapenem-resistant Enterobacteriaceae. We analyzed silver nanoparticles stabilized with citrate, chitosan and polyvinyl alcohol and commercial silver nanoparticle. Silver sulfadiazine and silver nitrate were used as control. Different methods were used: agar diffusion, minimum inhibitory concentration, minimum bactericidal concentration and time-kill. The activity of AgNPs using diffusion in solid media and the MIC methods showed similar effect against MDR and antimicrobial-susceptible isolates, with a higher effect against Gram-negative isolates. The better results were achieved with citrate and chitosan silver nanoparticle, both with MIC90 of 6.75 μg mL(-1), which can be due the lower stability of these particles and, consequently, release of Ag(+) ions as revealed by X-ray diffraction (XRD). The bactericidal effect was higher against antimicrobial-susceptible bacteria. It seems that agar diffusion method can be used as screening test, minimum inhibitory concentration/minimum bactericidal concentration and time kill showed to be useful methods. The activity of commercial silver nanoparticle and silver controls did not exceed the activity of the citrate and chitosan silver nanoparticles. The in vitro inhibitory effect was stronger against Gram

  15. Molecular Detection of Antimicrobial Resistance

    PubMed Central

    Fluit, Ad C.; Visser, Maarten R.; Schmitz, Franz-Josef

    2001-01-01

    The determination of antimicrobial susceptibility of a clinical isolate, especially with increasing resistance, is often crucial for the optimal antimicrobial therapy of infected patients. Nucleic acid-based assays for the detection of resistance may offer advantages over phenotypic assays. Examples are the detection of the methicillin resistance-encoding mecA gene in staphylococci, rifampin resistance in Mycobacterium tuberculosis, and the spread of resistance determinants across the globe. However, molecular assays for the detection of resistance have a number of limitations. New resistance mechanisms may be missed, and in some cases the number of different genes makes generating an assay too costly to compete with phenotypic assays. In addition, proper quality control for molecular assays poses a problem for many laboratories, and this results in questionable results at best. The development of new molecular techniques, e.g., PCR using molecular beacons and DNA chips, expands the possibilities for monitoring resistance. Although molecular techniques for the detection of antimicrobial resistance clearly are winning a place in routine diagnostics, phenotypic assays are still the method of choice for most resistance determinations. In this review, we describe the applications of molecular techniques for the detection of antimicrobial resistance and the current state of the art. PMID:11585788

  16. Surprising Alteration of Antibacterial Activity of 5″-Modified Neomycin against Resistant Bacteria

    PubMed Central

    Zhang, Jianjun; Chiang, Fang-I; Wu, Long; Czyryca, Przemyslaw Greg; Li, Ding; Chang, Cheng-Wei Tom

    2009-01-01

    A facile synthetic protocol for the production of neomycin B derivatives with various modifications at the 5″ position has been developed. Structural activity relationship (SAR) against aminoglycoside resistant bacteria equipped with various aminoglycoside-modifying enzymes (AME's) was investigated. Enzymatic and molecular modeling studies reveal that the superb substrate promiscuity of AME's allows the resistant bacteria to cope with diverse structural modifications despite the observation that several derivatives show enhanced antibacterial activity than the parent neomycin. Surprisingly, when testing synthetic neomycin derivatives against other human pathogens, two leads exhibit prominent activity against both Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) that are known to exert high level of resistance against clinically used aminoglycosides. These findings can be extremely useful in developing new aminoglycoside antibiotics against resistant bacteria. Our result also suggests that new biological and antimicrobial activities can be obtained by chemical modifications of old drugs. PMID:19012394

  17. Antimicrobial Resistance in Hospital-Acquired Gram-Negative Bacterial Infections

    PubMed Central

    Mehrad, Borna; Clark, Nina M.; Zhanel, George G.

    2015-01-01

    Aerobic gram-negative bacilli, including the family of Enterobacteriaceae and non-lactose fermenting bacteria such as Pseudomonas and Acinetobacter species, are major causes of hospital-acquired infections. The rate of antibiotic resistance among these pathogens has accelerated dramatically in recent years and has reached pandemic scale. It is no longer uncommon to encounter gram-negative infections that are untreatable using conventional antibiotics in hospitalized patients. In this review, we provide a summary of the major classes of gram-negative bacilli and their key mechanisms of antimicrobial resistance, discuss approaches to the treatment of these difficult infections, and outline methods to slow the further spread of resistance mechanisms. PMID:25940252

  18. Use of Extract of Citrus sinensis as an antimicrobial agent for foodborne zoonotic pathogens and spoilage bacteria

    USDA-ARS?s Scientific Manuscript database

    Foodborne pathogens remain global health problems despite concerted efforts to control the transmission of these microorganisms through food. The resurgence of drug resistant bacteria has renewed interest in developing and testing new sources of antimicrobial agents to control foodborne illness. Thi...

  19. Prevalence of antibiotic resistance in bacteria isolated from drinking well water available in Guinea-Bissau (West Africa).

    PubMed

    Machado, A; Bordalo, A A

    2014-08-01

    The dissemination of antibiotic-resistant bacteria and the spread of antibiotic resistance genes are a major public health concern worldwide, being even proposed as emerging contaminants. The aquatic environment is a recognized reservoir of antibiotic resistant bacteria, and antibiotic resistance genes have been recently detected in drinking water. In this study, the water quality and the prevalence of antibiotic resistance of heterotrophic culturable bacteria were characterized seasonally in wells that serve the population of Guinea-Bissau (West Africa) as the sole source of water for drinking and other domestic proposes. The results revealed that well water was unfit for human consumption independently of the season, owing to high acidity and heavy fecal contamination. Moreover, potentially pathogenic bacteria, which showed resistance to the most prescribed antibiotics in Guinea-Bissau, were isolated from well water, posing an additional health risk. Our results suggest that well water not only fosters the transmission of potential pathogenic bacteria, but also represents an important reservoir for the proliferation of antibiotic resistant bacteria, that can aggravate the potential to cause disease in a very vulnerable population that has no other alternative but to consume such water. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Antimicrobial susceptibility of clinical isolates of anaerobic bacteria in Ontario, 2010-2011.

    PubMed

    Marchand-Austin, Alex; Rawte, Prasad; Toye, Baldwin; Jamieson, Frances B; Farrell, David J; Patel, Samir N

    2014-08-01

    The local epidemiology of antimicrobial susceptibility patterns in anaerobic bacteria is important in guiding the empiric treatment of infections. However, susceptibility data are very limited on anaerobic organisms, particularly among non-Bacteroides organisms. To determine susceptibility profiles of clinically-significant anaerobic bacteria in Ontario Canada, anaerobic isolates from sterile sites submitted to Public Health Ontario Laboratory (PHOL) for identification and susceptibility testing were included in this study. Using the E-test method, isolates were tested for various antimicrobials including, penicillin, cefoxitin, clindamycin, meropenem, piperacillin-tazobactam and metronidazole. The MIC results were interpreted based on guidelines published by Clinical and Laboratory Standards Institute. Of 2527 anaerobic isolates submitted to PHOL, 1412 were either from sterile sites or bronchial lavage, and underwent susceptibility testing. Among Bacteroides fragilis, 98.2%, 24.7%, 1.6%, and 1.2% were resistant to penicillin, clindamycin, piperacillin-tazobactam, and metronidazole, respectively. Clostridium perfringens was universally susceptible to penicillin, piperacillin-tazobactam, and meropenem, whereas 14.2% of other Clostridium spp. were resistant to penicillin. Among Gram-positive anaerobes, Actinomyces spp., Parvimonas micra and Propionibacterium spp. were universally susceptible to β-lactams. Eggerthella spp., Collinsella spp., and Eubacterium spp. showed variable resistance to penicillin. Among Gram-negative anaerobes, Fusobacterium spp., Prevotella spp., and Veillonella spp. showed high resistance to penicillin but were universally susceptible to meropenem and piperacillin-tazobactam. The detection of metronidazole resistant B. fragilis is concerning as occurrence of these isolates is extremely rare. These data highlight the importance of ongoing surveillance to provide clinically relevant information to clinicians for empiric management of

  1. Can microbial cells develop resistance to oxidative stress in antimicrobial photodynamic inactivation?

    PubMed

    Kashef, Nasim; Hamblin, Michael R

    2017-03-01

    Infections have been a major cause of disease throughout the history of humans on earth. With the introduction of antibiotics, it was thought that infections had been conquered. However, bacteria have been able to develop resistance to antibiotics at an exponentially increasing rate. The growing threat from multi-drug resistant organisms calls for intensive action to prevent the emergence of totally resistant and untreatable infections. Novel, non-invasive, non-antibiotic strategies are needed that act more efficiently and faster than current antibiotics. One promising alternative is antimicrobial photodynamic inactivation (APDI), an approach that produces reactive oxygen species when dyes and light are combined. So far, it has been questionable if bacteria can develop resistance against APDI. This review paper gives an overview of recent studies concerning the susceptibility of bacteria towards oxidative stress, and suggests possible mechanisms of the development of APDI-resistance that should at least be addressed. Some ways to potentiate APDI and also to overcome future resistance are suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The Three Bacterial Lines of Defense against Antimicrobial Agents

    PubMed Central

    Zhou, Gang; Shi, Qing-Shan; Huang, Xiao-Mo; Xie, Xiao-Bao

    2015-01-01

    Antimicrobial agents target a range of extra- and/or intracellular loci from cytoplasmic wall to membrane, intracellular enzymes and genetic materials. Meanwhile, many resistance mechanisms employed by bacteria to counter antimicrobial agents have been found and reported in the past decades. Based on their spatially distinct sites of action and distribution of location, antimicrobial resistance mechanisms of bacteria were categorized into three groups, coined the three lines of bacterial defense in this review. The first line of defense is biofilms, which can be formed by most bacteria to overcome the action of antimicrobial agents. In addition, some other bacteria employ the second line of defense, the cell wall, cell membrane, and encased efflux pumps. When antimicrobial agents permeate the first two lines of defense and finally reach the cytoplasm, many bacteria will make use of the third line of defense, including alterations of intracellular materials and gene regulation to protect themselves from harm by bactericides. The presented three lines of defense theory will help us to understand the bacterial resistance mechanisms against antimicrobial agents and design efficient strategies to overcome these resistances. PMID:26370986

  3. Next-Generation Probiotics Targeting Clostridium difficile through Precursor-Directed Antimicrobial Biosynthesis

    PubMed Central

    Auchtung, Jennifer; Brown, Aaron; Boonma, Prapaporn; Oezguen, Numan; Ross, Caná L.; Luna, Ruth Ann; Runge, Jessica; Versalovic, James; Peniche, Alex; Dann, Sara M.; Britton, Robert A.; Haag, Anthony; Savidge, Tor C.

    2017-01-01

    ABSTRACT Integration of antibiotic and probiotic therapy has the potential to lessen the public health burden of antimicrobial-associated diseases. Clostridium difficile infection (CDI) represents an important example where the rational design of next-generation probiotics is being actively pursued to prevent disease recurrence. Because intrinsic resistance to clinically relevant antibiotics used to treat CDI (vancomycin, metronidazole, and fidaxomicin) is a desired trait in such probiotic species, we screened several bacteria and identified Lactobacillus reuteri to be a promising candidate for adjunct therapy. Human-derived L. reuteri bacteria convert glycerol to the broad-spectrum antimicrobial compound reuterin. When supplemented with glycerol, strains carrying the pocR gene locus were potent reuterin producers, with L. reuteri 17938 inhibiting C. difficile growth at a level on par with the level of growth inhibition by vancomycin. Targeted pocR mutations and complementation studies identified reuterin to be the precursor-induced antimicrobial agent. Pathophysiological relevance was demonstrated when the codelivery of L. reuteri with glycerol was effective against C. difficile colonization in complex human fecal microbial communities, whereas treatment with either glycerol or L. reuteri alone was ineffective. A global unbiased microbiome and metabolomics analysis independently confirmed that glycerol precursor delivery with L. reuteri elicited changes in the composition and function of the human microbial community that preferentially targets C. difficile outgrowth and toxicity, a finding consistent with glycerol fermentation and reuterin production. Antimicrobial resistance has thus been successfully exploited in the natural design of human microbiome evasion of C. difficile, and this method may provide a prototypic precursor-directed probiotic approach. Antibiotic resistance and substrate bioavailability may therefore represent critical new determinants of

  4. Antimicrobial resistance and genetic profiling of Escherichia coli from a commercial beef packing plant.

    PubMed

    Aslam, Mueen; Service, Cara

    2006-07-01

    The objective of this study was to investigate the extent of antimicrobial resistance and to genetically characterize resistant Escherichia coli recovered from a commercial beef packing plant. E. coli isolates were recovered by a hydrophobic grid membrane filtration method by direct plating on SD-39 medium. A total of 284 isolates comprising 71, 36, 55, 52, and 70 isolates from animal hides, washed carcasses, conveyers, beef trimmings, and ground beef, respectively, were analyzed. The susceptibility of E. coli isolates to 15 antimicrobial agents was evaluated with an automated broth microdilution system, and the genetic characterization of these isolates was performed by the random amplified polymorphic DNA (RAPD) method. Of the 284 E. coli isolates, 56% were sensitive to all 15 antimicrobial agents. Resistance to tetracycline, ampicillin, and streptomycin was observed in 38, 9, and 6% of the isolates, respectively. Resistance to one or more antimicrobial agents was observed in 51% of the E. coli isolates recovered from the hides but in only 25% of the E. coli from the washed carcasses. Resistance to one or more antimicrobial agents was observed in 49, 50, and 37% of the isolates recovered from conveyers, beef trimmings, and ground beef, respectively. The RAPD pattern data showed that the majority of resistant E. coli isolates were genetically diverse. Only a few RAPD types of resistant strains were shared among various sample sources. The results of this study suggest that antimicrobial-resistant E. coli isolates were prevalent during all stages of commercial beef processing and that considerably higher numbers of resistant E. coli were present on conveyers, beef trimmings, and ground beef than on dressed carcasses. This stresses the need for improving hygienic conditions during all stages of commercial beef processing and meatpacking to avoid the risks of transfer of antimicrobial-resistant bacteria to humans.

  5. Bacillus subtilis from Soybean Food Shows Antimicrobial Activity for Multidrug-Resistant Acinetobacter baumannii by Affecting the adeS Gene.

    PubMed

    Wang, Tieshan; Su, Jianrong

    2016-12-28

    Exploring novel antibiotics is necessary for multidrug-resistant pathogenic bacteria. Because the probiotics in soybean food have antimicrobial activities, we investigated their effects on multidrug-resistant Acinetobacter baumannii . Nineteen multidrug-resistant A. baumannii strains were clinifcally isolated as an experimental group and 11 multidrug-sensitive strains as controls. The growth rates of all bacteria were determined by using the analysis for xCELLigence Real-Time Cell. The combination of antibiotics showed synergistic effects on the strains in the control group but no effect on the strains in the experimental group. Efflux pump gene adeS was absent in all the strains from the control group, whereas it exists in all the strains from the experimental group. Furthermore, all the strains lost multidrug resistance when an adeS inhibitor was used. One strain of probiotics isolated from soybean food showed high antimicrobial activity for multidrug-resistant A. baumannii . The isolated strain belongs to Bacillus subtilis according to 16S RNA analysis. Furthermore, E. coli showed multidrug resistance when it was transformed with the adeS gene from A. baumannii whereas the resistant bacteria could be inhibited completely by isolated Bacillus subtilis . Thus, probiotics from soybean food provide potential antibiotics against multidrug-resistant pathogenic bacteria.

  6. Stepwise impact of urban wastewater treatment on the bacterial community structure, antibiotic contents, and prevalence of antimicrobial resistance.

    PubMed

    Wang, Mingyu; Shen, Weitao; Yan, Lei; Wang, Xin-Hua; Xu, Hai

    2017-12-01

    Bacteria, antibiotics, and antibiotic resistance determinants are key biological pollutants in aquatic systems, which may lead to bacterial infections or prevent the cure of bacterial infections. In this study, we investigated how the wastewater treatment processes in wastewater treatment plants (WWTPs) affect these pollutants. We found that the addition of oxygen, polyaluminum chloride (PAC), and polyacrylamide (PAM), as well as ultraviolet (UV) disinfection could significantly alter the bacterial communities in the water samples. An overall shift from Gram-negative bacteria to Gram-positive bacteria was observed throughout the wastewater treatment steps, but the overall bacterial biomass was not reduced in the WWTP samples. The antibiotic contents were reduced by the WWTP, but the size of the reduction and the step when antibiotic degradation occurred differed among antibiotics. Ciprofloxacin, sulfamethoxazole and erythromycin could be removed completely by the WWTP, whereas cephalexin could not. The removal of ciprofloxacin, cephalexin, and erythromycin occurred in the anaerobic digester, whereas the removal of sulfamethoxazole occurred after the addition of PAC and PAM, and UV disinfection. Antimicrobial resistance determinants were highly prevalent in all of the samples analyzed, except for those targeting vancomycin and colistin. However, wastewater treatment was ineffective at removing antimicrobial resistance determinants from wastewater. There were strong correlations between intI1, floR, sul1, and ermB, thereby suggesting the importance of integrons for the spread of these antimicrobial resistance genes. In general, this study comprised a stepwise analysis of the impact of WWTPs on three biological pollutants: bacteria, antibiotics, and antimicrobial resistance determinants, where our results suggest that the design of WWTPs needs to be improved to address the threats due to these pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Antimicrobial resistance pattern in a tertiary care hospital: An observational study

    PubMed Central

    Saravanan, Revathy; Raveendaran, Vinod

    2013-01-01

    , nitrofurantoin, gentamycin and doxycycline among the gram-negative bacteria. Macrolides, clindamycin, gentamycin, nitrofurantoin, vancomycin were the most sensitive antimicrobials against the gram-positive bacteria. Lack of knowledge on the consequences of inappropriate use of antibiotics was exhibited by 63% of subjects in our study. Conclusions: AMR was more with hospital acquired organisms and against commonly used antibiotics that are available since long period. Variation of resistance and sensitivity pattern with time and geographical location is identified. Periodic AMR monitoring and rotation of antibiotics are suggested to restrict further emergence of resistance. PMID:24808672

  8. The Rising Tide of Antimicrobial Resistance in Aquaculture: Sources, Sinks and Solutions.

    PubMed

    Watts, Joy E M; Schreier, Harold J; Lanska, Lauma; Hale, Michelle S

    2017-06-01

    As the human population increases there is an increasing reliance on aquaculture to supply a safe, reliable, and economic supply of food. Although food production is essential for a healthy population, an increasing threat to global human health is antimicrobial resistance. Extensive antibiotic resistant strains are now being detected; the spread of these strains could greatly reduce medical treatment options available and increase deaths from previously curable infections. Antibiotic resistance is widespread due in part to clinical overuse and misuse; however, the natural processes of horizontal gene transfer and mutation events that allow genetic exchange within microbial populations have been ongoing since ancient times. By their nature, aquaculture systems contain high numbers of diverse bacteria, which exist in combination with the current and past use of antibiotics, probiotics, prebiotics, and other treatment regimens-singularly or in combination. These systems have been designated as "genetic hotspots" for gene transfer. As our reliance on aquaculture grows, it is essential that we identify the sources and sinks of antimicrobial resistance, and monitor and analyse the transfer of antimicrobial resistance between the microbial community, the environment, and the farmed product, in order to better understand the implications to human and environmental health.

  9. BF-30 effectively inhibits ciprofloxacin-resistant bacteria in vitro and in a rat model of vaginosis.

    PubMed

    Wang, Jing; Li, Bing; Li, Yang; Dou, Jie; Hao, Qingru; Tian, Yuwei; Wang, Hui; Zhou, Changlin

    2014-07-01

    Bacterial infections are becoming increasingly difficult to treat due to the increasing number of multidrug-resistant strains. Cathelicidin-BF (BF-30) is a cathelicidin-like antimicrobial peptide and exhibits broad antimicrobial activity against bacteria. In the present study, the antibacterial activity of BF-30 against ciprofloxacin-resistant Escherichia coli and Staphylococcus aureus was examined, and the protective effects of this peptide against these bacteria in rats with bacterial vaginosis were identified for the first time. The data showed that BF-30 had effective antimicrobial activities against ciprofloxacin-resistant E. coli and S. aureus. The minimal inhibitory concentrations for both bacterial strains were 16 μg/ml, and the minimal bactericidal concentrations were 64 and 128 μg/ml, respectively. A time course experiment showed that the CFU counts rapidly decreased after BF-30 treatment, and the bacteria were nearly eliminated within 4 h. BF-30 could reduce the fold change (CFU/ml) in local colonization by drug-resistant E. coli and S. aureus to 0.01 at a dose of 0.8 mg/kg/day in the rats' vaginal secretions. In addition, BF-30 induced membrane permeabilization and bound to the genomic DNA, interrupting protein synthesis. Taken together, our data demonstrate that BF-30 has potential therapeutic value for the prevention and treatment of bacterial vaginosis.

  10. Characterizing relationships among fecal indicator bacteria ...

    EPA Pesticide Factsheets

    Bed sediments of streams and rivers may store high concentrations of fecal indicator bacteria (FIB) and pathogens. Due to resuspension events, these contaminants can be mobilized into the water column and affect overall water quality. Other bacterial indicators such as microbial source tracking (MST) markers, developed to determine potential sources of fecal contamination, can also be resuspended from bed sediments. The primary objective of this study was to predict occurrence of waterborne pathogens in water and streambed sediments using a simple statistical model that includes traditionally measured FIB, environmental parameters and source allocation, using MST markers as predictor variables. Synoptic sampling events were conducted during baseflow conditions downstream from agricultural (AG), forested (FORS), and wastewater pollution control plant (WPCP) land uses. Concentrations of FIB and MST markers were measured in water and sediments, along with occurrences of the enteric pathogens Campylobacter, Listeria and Salmonella, and the virulence gene that carries Shiga toxin, stx2. Pathogens were detected in water more often than in underlying sediments. Shiga toxin was significantly related to land use, with concentrations of the ruminant marker selected as an independent variable that could correctly classify 76% and 64% of observed Shiga toxin occurrences in water and sediment, respectively. FIB concentrations and water quality parameters were also selected a

  11. Increased prevalence of antibiotic-resistant E. coli in gulls sampled in southcentral Alaska is associated with urban environments

    USGS Publications Warehouse

    Atterby, Clara; Ramey, Andrew M.; Gustafsson Hall, Gabriel; Jarhult, Josef; Borjesson, Stefan; Bonnedahl, Jonas

    2016-01-01

    BackgroundAntibiotic-resistant bacteria pose challenges to healthcare delivery systems globally; however, limited information is available regarding the prevalence and spread of such bacteria in the environment. The aim of this study was to compare the prevalence of antibiotic-resistant bacteria in large-bodied gulls (Larus spp.) at urban and remote locations in Southcentral Alaska to gain inference into the association between antibiotic resistance in wildlife and anthropogenically influenced habitats.MethodsEscherichia coli was cultured (n=115 isolates) from fecal samples of gulls (n=160) collected from a remote location, Middleton Island, and a more urban setting on the Kenai Peninsula.ResultsScreening of E. coli from fecal samples collected from glaucous-winged gulls (Larus glaucescens) at Middleton Island revealed 8% of isolates were resistant to one or more antibiotics and 2% of the isolates were resistant to three or more antibiotics. In contrast, 55% of E. coli isolates derived from fecal samples collected from large-bodied gulls (i.e. glaucous, herring [Larus argentatus], and potentially hybrid gulls) on the Kenai Peninsula were resistant to one or more antibiotics and 22% were resistant to three or more antibiotics. In addition, total of 16% of the gull samples from locations on the Kenai Peninsula harbored extended-spectrum cephalosporin-resistant E. coli isolates (extended-spectrum beta-lactamases [ESBL] and plasmid-encoded AmpC [pAmpC]), in contrast to Middleton Island where no ESBL- or pAmpC-producing isolates were detected.ConclusionOur findings indicate that increased prevalence of antibiotic resistance is associated with urban environments in Southcentral Alaska and presumably influenced by anthropogenic impacts. Further investigation is warranted to assess how migratory birds may maintain and spread antimicrobial-resistant bacteria of relevance to human and animal health.

  12. Fate and Enumeration Problems of Fecal Coliform Bacteria in Runoff Waters from Terrestrial Ecosystems.

    DTIC Science & Technology

    1980-09-01

    bacteria and also for the development of a surface organic layer on the plots that aided in the removal of wastewater bacteria through filtration and...better conditions not only for protozoan predation of fecal bacteria but also for the development of a surface organic layer on the plots. This organic... layer acted to increase the detention of the wastewater bacteria through filtration and entrapment. The intermittently treated plots promoted the

  13. Antimicrobial resistance profiles of common mastitis pathogens on Canadian dairy farms.

    PubMed

    Saini, V; McClure, J T; Léger, D; Keefe, G P; Scholl, D T; Morck, D W; Barkema, H W

    2012-08-01

    Monitoring of antimicrobial resistance (AMR) in bacteria has clinical and public health significance. The present study determined prevalence of AMR in common mastitis pathogens Staphylococcus aureus, including methicillin-resistant Staph. aureus (MRSA; n=1,810), Escherichia coli (n=394), and Klebsiella species (n=139), including extended-spectrum β-lactamase (ESBL)-producing E. coli and Klebsiella species, isolated from milk samples on 89 dairy farms in 6 Canadian provinces. Minimum inhibitory concentrations (MIC) were determined using the Sensititer bovine mastitis plate (Trek Diagnostic Systems Inc., Cleveland, OH) and a National Antimicrobial Resistance Monitoring System gram-negative panel containing antimicrobials commonly used for mastitis treatment and control. Denim blue chromogenic agar and real-time PCR were used to screen and confirm MRSA, respectively. Resistance proportion estimates ranged from 0% for cephalothin and oxacillin to 8.8% for penicillin in Staph. aureus isolates, and 15% of the resistant Staph. aureus isolates were multidrug resistant. One MRSA isolate was confirmed (prevalence: 0.05%). Resistance proportion estimates ranged from 0% for ceftriaxone and ciprofloxacin to 14.8% for tetracycline in E. coli, and 0% for amikacin, ceftiofur, ciprofloxacin, and nalidixic acid to 18.6% for tetracycline in Klebsiella species isolates. Further, 62.8 and 55% of the resistant E. coli and Klebsiella species isolates were multidrug resistant, respectively. Resistance to >5 and >2 antimicrobials was most common in E. coli and Klebsiella species isolates, respectively, and no ESBL producers were found. Prevalence of AMR in bovine mastitis pathogens was low. Most gram-negative udder pathogens were multidrug resistant; MRSA was rarely found, and ESBL E. coli and Klebsiella species isolates were absent in Canadian milk samples. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. Triclosan- resistant bacteria isolated from feedlot and residential soils

    PubMed Central

    WELSCH, TANNER T.; GILLOCK, ERIC T.

    2014-01-01

    Triclosan is an antimicrobial agent that is currently incorporated into hundreds of consumer and medical products. It can be either a bacteriostatic or bactericidal agent, depending on its formulation. It has activity against Gram-positive and Gram-negative bacteria, as well as some viruses and protists. The purpose of this study was to determine whether triclosan-resistant bacteria could be isolated from the soil. Soils from cattle feedlots and residential lawns were collected and assayed for the presence of these organisms by plating samples on growth media containing triclosan. Organisms were subsequently identified by partial 16S rRNA sequencing analysis. All the organisms isolated in this study were Gram-negative rods, with members of genus Pseudomonas being particularly well represented. This result may not be surprising because Gram-negative organisms are generally more resistant to triclosan, and since Pseudomonas bacteria are known to have numerous efflux mechanisms for dealing with harmful substances. PMID:21391038

  15. Comparison of fecal indicators with pathogenic bacteria and rotavirus in groundwater.

    PubMed

    Ferguson, Andrew S; Layton, Alice C; Mailloux, Brian J; Culligan, Patricia J; Williams, Daniel E; Smartt, Abby E; Sayler, Gary S; Feighery, John; McKay, Larry D; Knappett, Peter S K; Alexandrova, Ekaterina; Arbit, Talia; Emch, Michael; Escamilla, Veronica; Ahmed, Kazi Matin; Alam, Md Jahangir; Streatfield, P Kim; Yunus, Mohammad; van Geen, Alexander

    2012-08-01

    Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Susceptibility of Pediococcus isolates to antimicrobial compounds in relation to hop-resistance and beer-spoilage.

    PubMed

    Haakensen, Monique; Vickers, David M; Ziola, Barry

    2009-09-07

    Though important in the context of food microbiology and as potential pathogens in immuno-compromised humans, bacterial isolates belonging to the genus Pediococcus are best known for their association with contamination of ethanol fermentation processes (beer, wine, or fuel ethanol). Use of antimicrobial compounds (e.g., hop-compounds, Penicillin) by some industries to combat Pediococcus contaminants is long-standing, yet knowledge about the resistance of pediococci to antimicrobial agents is minimal. Here we examined Pediococcus isolates to determine whether antibiotic resistance is associated with resistance to hops, presence of genes known to correlate with beer spoilage, or with ability to grow in beer. Lactic acid bacteria susceptibility test broth medium (LSM) used in combination with commercially available GPN3F antimicrobial susceptibility plates was an effective method for assessing antimicrobial susceptibility of Pediococcus isolates. We report the finding of Vancomycin-susceptible Pediococcus isolates from four species. Interestingly, we found that hop-resistant, beer-spoilage, and beer-spoilage gene-harbouring isolates had a tendency to be more susceptible, rather than more resistant, to antimicrobial compounds. Our findings indicate that the mechanisms involved in conferring hop-resistance or ability to spoil beer by Pediococcus isolates are not associated with resistance to antibiotics commonly used for treatment of human infections. Also, Vancomycin-resistance was found to be isolate-specific and not intrinsic to the genus as previously believed.

  17. Antimicrobial resistance profile of urinary tract infection at a secondary care hospital in Medan, Indonesia

    NASA Astrophysics Data System (ADS)

    Rahimi, A.; Saragih, R. H.; Nainggolan, R.

    2018-03-01

    Urinary tract infection (UTI) is a considerable health problem which ranks as the second leading cause of infection after respiratory tract one. Antimicrobial resistance in UTI has become a burden in the management of the disease due to high usage of antibiotics. A comprehensive understanding of the etiology and the antimicrobial resistance of the uropathogenic bacteria is essential to provide adequate treatment. This study aims to determine the etiologic agents and their susceptibility pattern in UTI patients. The analysis was performed retrospectively on culture isolates obtained from urine samples received at the Department of Microbiology, Dr.Pirngadi General Hospital, Medan, Indonesia in the period from January 2015 until December 2016. Higher prevalence of UTI was found in female participants of the study in comparison with males. Enterobacter (64.58%) was the most common bacteria revealed as the etiologic agent, followed by E. coli (11.46%), Citrobacter and Klebsiella (9.38% each). Amikacin and meropenem were the most sensitive antimicrobial agents for Enterobacter, E. coli, Citrobacter, and Klebsiella, showing low resistance rate. This study showed that Enterobacter was the most dominant bacterial pathogen of UTI. Amikacin and meropenem were the antibiotics with high sensitivity for UTI treatment.

  18. Antimicrobial activities of commercial essential oils and their components against food-borne pathogens and food spoilage bacteria

    PubMed Central

    Mith, Hasika; Duré, Rémi; Delcenserie, Véronique; Zhiri, Abdesselam; Daube, Georges; Clinquart, Antoine

    2014-01-01

    This study was undertaken to determine the in vitro antimicrobial activities of 15 commercial essential oils and their main components in order to pre-select candidates for potential application in highly perishable food preservation. The antibacterial effects against food-borne pathogenic bacteria (Listeria monocytogenes, Salmonella Typhimurium, and enterohemorrhagic Escherichia coli O157:H7) and food spoilage bacteria (Brochothrix thermosphacta and Pseudomonas fluorescens) were tested using paper disk diffusion method, followed by determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Most of the tested essential oils exhibited antimicrobial activity against all tested bacteria, except galangal oil. The essential oils of cinnamon, oregano, and thyme showed strong antimicrobial activities with MIC ≥ 0.125 μL/mL and MBC ≥ 0.25 μL/mL. Among tested bacteria, P. fluorescens was the most resistant to selected essential oils with MICs and MBCs of 1 μL/mL. The results suggest that the activity of the essential oils of cinnamon, oregano, thyme, and clove can be attributed to the existence mostly of cinnamaldehyde, carvacrol, thymol, and eugenol, which appear to possess similar activities against all the tested bacteria. These materials could be served as an important natural alternative to prevent bacterial growth in food products. PMID:25473498

  19. Resistance to quaternary ammonium compounds in food-related bacteria.

    PubMed

    Sidhu, Maan Singh; Sørum, Henning; Holck, Askild

    2002-01-01

    Microbial resistance to antimicrobial agents continues to be a major problem. The frequent use and misuse of disinfectants based on quaternary ammonium compounds (QACs) in food-processing industries have imposed a selective pressure and may contribute to the emergence of disinfectant-resistant microorganisms. A total number of 1,325 Gram-negative isolates (Escherichia coli, other coliforms Vibrio spp., and Aeromonas spp.) and 500 Enterococcus spp. from food and food-processing industries and fish farming were screened for natural resistance to the QAC-based disinfectant benzalkonium chloride (BC). Of the 1,825 isolates, 16 strains, mainly from meat retail shops, showed low-level resistance to BC. None of the Enterococcus spp. from broiler, cattle, and pigs, the antibiotic-resistant E. coli from pig intestine and fish pathogens Vibrio spp. and Aeromonas spp. from the Norwegian fish farming industry were resistant to BC. The BC-resistant strains were examined for susceptibility to 15 different antibiotics, disinfectants, and dyes. No systematic cross-resistance between BC and any of the other antimicrobial agents tested was detected. Stable enhanced resistance in Enterobacter cloacae isolates was demonstrated by step-wise adaptation in increasing concentrations of BC. In conclusion, BC resistance among food-associated Gram-negative bacteria and Enterococcus spp. is not frequent, but resistance may develop to user concentrations after exposure to sublethal concentrations of BC.

  20. Construction of Zinc Oxide into Different Morphological Structures to Be Utilized as Antimicrobial Agent against Multidrug Resistant Bacteria

    PubMed Central

    Elkady, M. F.; Shokry Hassan, H.; Hafez, Elsayed E.; Fouad, Ahmed

    2015-01-01

    Nano-ZnO has been successfully implemented in particles, rods, and tubes nanostructures via sol-gel and hydrothermal techniques. The variation of the different preparation parameters such as reaction temperature, time, and stabilizer agents was optimized to attain different morphological structures. The influence of the microwave annealing process on ZnO crystallinity, surface area, and morphological structure was monitored using XRD, BET, and SEM techniques, respectively. The antimicrobial activity of zinc oxide produced in nanotubes structure was examined against four different multidrug resistant bacteria: Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. The activity of produced nano-ZnO was determined by disc diffusion technique and the results revealed that ZnO nanotubes recorded high activity against the studied strains due to their high surface area equivalent to 17.8 m2/g. The minimum inhibitory concentration (MIC) of ZnO nanotubes showed that the low concentrations of ZnO nanotubes could be a substitution for the commercial antibiotics when approached in suitable formula. Although the annealing process of ZnO improves the degree of material crystallinity, however, it declines its surface area and consequently its antimicrobial activity. PMID:26451136

  1. Antimicrobial Activities of Leaf Extracts of Guava (Psidium guajava L.) on Two Gram-Negative and Gram-Positive Bacteria

    PubMed Central

    Biswas, Bipul; Rogers, Kimberly; McLaughlin, Fredrick; Yadav, Anand

    2013-01-01

    Aim. To determine the antimicrobial potential of guava (Psidium guajava) leaf extracts against two gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and two gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) which are some of foodborne and spoilage bacteria. The guava leaves were extracted in four different solvents of increasing polarities (hexane, methanol, ethanol, and water). The efficacy of these extracts was tested against those bacteria through a well-diffusion method employing 50 μL leaf-extract solution per well. According to the findings of the antibacterial assay, the methanol and ethanol extracts of the guava leaves showed inhibitory activity against gram-positive bacteria, whereas the gram-negative bacteria were resistant to all the solvent extracts. The methanol extract had an antibacterial activity with mean zones of inhibition of 8.27 and 12.3 mm, and the ethanol extract had a mean zone of inhibition of 6.11 and 11.0 mm against B. cereus and S. aureus, respectively. On the basis of the present finding, guava leaf-extract might be a good candidate in the search for a natural antimicrobial agent. This study provides scientific understanding to further determine the antimicrobial values and investigate other pharmacological properties. PMID:24223039

  2. [The environment as a reservoir for antimicrobial resistance : A growing problem for public health?

    PubMed

    Westphal-Settele, Kathi; Konradi, Sabine; Balzer, Frederike; Schönfeld, Jens; Schmithausen, Ricarda

    2018-05-01

    Antimicrobial resistance (AMR) is a threat to public and animal health on the global scale. The origin of the genes associated with resistance has long been unknown. Recently, there is a growing body of evidence demonstrating that environmental bacteria are resistant to a multitude of antibiotic substances and that this environmental reservoir of AMR is still growing. The analysis of the genomes of bacterial pathogens indicates that they have acquired their resistance profiles by incorporating different genetic elements through horizontal gene transfer. The ancestors of pathogenic bacteria, as well as the origin of resistance determinants, lay most likely in the environmental microbiota. Indeed, there is some evidence that at least some clinically relevant resistance genes have originated in environmental bacterial species. Thus, feasible measures are required to reduce the risks posed by AMR genes and resistant bacteria that occur in the environment. It has been shown that a concurrence of factors, such as high concentrations of antibiotics or heavy metals used as biocides and high bacterial densities, promote development and spread of antimicrobial resistance. For this purpose, it is essential to restrict the use of antibiotics for the treatment of livestock and humans to medical necessity, as well as to reduce the application of biocides and heavy metals in animal husbandry. Moreover, it is important to further develop sanitary measures at the interface between the environment and clinical settings or livestock farming.

  3. Evaluation of the routine antimicrobial susceptibility testing results of clinically significant anaerobic bacteria in a Slovenian tertiary-care hospital in 2015.

    PubMed

    Jeverica, Samo; Kolenc, Urša; Mueller-Premru, Manica; Papst, Lea

    2017-10-01

    The aim of our study was to determined antimicrobial susceptibility profiles of 2673 clinically significant anaerobic bacteria belonging to the major genera, isolated in 2015 in a large tertiary-care hospital in Slovenia. The species identification was performed by MALDI-TOF mass spectrometry. Antimicrobial susceptibility was determined immediately at the isolation of the strains against: penicillin, co-amoxiclav, imipenem, clindamycin and metronidazole, using gradient diffusion methodology and EUCAST breakpoints. The most frequent anaerobes were Bacteroides fragilis group with 31% (n = 817), Gram positive anaerobic cocci (GPACs) with 22% (n = 589), Prevotella with 14% (n = 313) and Propionibacterium with 8% (n = 225). Metronidazole has retained full activity (100%) against all groups of anaerobic bacteria intrinsically susceptible to it. Co-amoxiclav and imipenem were active against most tested anaerobes with zero or low resistance rates. However, observed resistance to co-amoxiclav (8%) and imipenem (1%) is worrying especially among B. fragilis group isolates. High overall resistance (23%) to clindamycin was detected in our study and was highest among the genera Prevotella, Bacteroides, Parabacteroides, GPACs and Clostridium. Routine testing of antimicrobial susceptibility of clinically relevant anaerobic bacteria is feasible and provides good surveillance data. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. [Antimicrobial resistance forever? Judicious and appropriate use of antibiotics].

    PubMed

    Cagliano, Stefano

    2015-06-01

    This article takes its cue from the original work of sir Alexander Fleming on penicillin, published in the first issue of Recenti Progressi in Medicina in 1946 and reproduced here on the occasion of the approaching 70-year anniversary of the journal. In 1928, at the time when penicillin was discovered, it could not be imagined that bacterial resistance to antibiotics would develop so rapidly: the introduction of every new class of antibiotics has been shortly followed by the emergence of new strains of bacteria resistant to that class. Bacterial resistance to antibiotic treatment is a huge concern. In this respect, an action plan against antimicrobial resistance has been devised in the United States that is targeted for a 50% reduction over the next five years.

  5. Correlation between antimicrobial consumption and antimicrobial resistance of Pseudomonas aeruginosa in a hospital setting: a 10-year study.

    PubMed

    Mladenovic-Antic, S; Kocic, B; Velickovic-Radovanovic, R; Dinic, M; Petrovic, J; Randjelovic, G; Mitic, R

    2016-10-01

    Antimicrobial resistance is one of the greatest threats to human health. One of the most important factors leading to the emergence of resistant bacteria is overuse of antibiotics. The purpose of this study was to investigate the correlation between antimicrobial usage and bacterial resistance of Pseudomonas aeruginosa (P. aeruginosa) over a 10-year period in the Clinical Center Niš, one of the biggest tertiary care hospitals in Serbia. We focused on possible relationships between the consumption of carbapenems and beta-lactam antibiotics and the rates of resistance of P. aeruginosa to carbapenems. We recorded utilization of antibiotics expressed as defined daily doses per 100 bed days (DBD). Bacterial resistance was reported as the percentage of resistant isolates (percentage of all resistant and intermediate resistant strains) among all tested isolates. A significant increasing trend in resistance was seen in imipenem (P < 0·05, Spearman ρ = 0·758) and meropenem (P < 0·05, ρ = 0·745). We found a significant correlation between aminoglycoside consumption and resistance to amikacin (P < 0·01, Pearson r = 0·837) and gentamicin (P < 0·01, Pearson r = 0·827). The correlation between the consumption of carbapenems and resistance to imipenem in P. aeruginosa shows significance (P < 0·01, Pearson r = 0·795), whereas resistance to meropenem showed a trend towards significance (P > 0·05, Pearson r = 0·607). We found a very good correlation between the use of all beta-lactam and P. aeruginosa resistance to carbapenems (P < 0·01, Pearson r = 0·847 for imipenem and P < 0·05, Pearson r = 0·668 for meropenem). Our data demonstrated a significant increase in antimicrobial resistance to carbapenems, significant correlations between the consumption of antibiotics, especially carbapenems and beta-lactams, and rates of antimicrobial resistance of P. aeruginosa to imipenem and meropenem. © 2016 John Wiley & Sons Ltd.

  6. Antimicrobial resistance trends among Escherichia coli isolates obtained from dairy cattle in the northeastern United States, 2004-2011.

    PubMed

    Cummings, Kevin J; Aprea, Victor A; Altier, Craig

    2014-01-01

    Monitoring antimicrobial resistance trends among bacteria isolated from food animals and people is necessary to inform risk analyses and guide public policy regarding antimicrobial use. Our objectives were to describe the antimicrobial resistance status of Escherichia coli isolates from dairy cattle in the northeastern United States and to identify trends in resistance to selected antimicrobial agents over time. We collected data retrospectively for all bovine E. coli isolates that were obtained from samples submitted to Cornell University's Animal Health Diagnostic Center between January 1, 2004 and December 31, 2011. We investigated temporal trends in the prevalence of resistant E. coli for each antimicrobial agent using the Cochran-Armitage trend test. Antimicrobial susceptibility testing was performed on 3373 bovine E. coli isolates from clinical samples submitted during the study period. Overall resistance to each antimicrobial agent ranged from 2.7% (enrofloxacin) to 91.3% (oxytetracycline). There was evidence of a significantly decreasing trend in prevalence of resistance to several agents: chlortetracycline, florfenicol, neomycin, oxytetracycline, spectinomycin, and trimethoprim/sulfamethoxazole. However, a significantly increasing trend in prevalence of resistance to enrofloxacin was also evident. These results do not support the idea that current antimicrobial use practices on dairy operations are driving a general increase in the emergence and dissemination of drug-resistant E. coli in the region served by the laboratory. However, resistance to some drugs remained consistently high during the study period, and increasing resistance to enrofloxacin is a key area of concern.

  7. Antimicrobial Drug Use and Resistance in Europe

    PubMed Central

    van de Sande-Bruinsma, Nienke; Verloo, Didier; Tiemersma, Edine; Monen, Jos; Goossens, Herman; Ferech, Matus

    2008-01-01

    Our study confronts the use of antimicrobial agents in ambulatory care with the resistance trends of 2 major pathogens, Streptococcus pneumoniae and Escherichia coli, in 21 European countries in 2000–2005 and explores whether the notion that antimicrobial drug use determines resistance can be supported by surveillance data at national aggregation levels. The data obtained from the European Surveillance of Antimicrobial Consumption and the European Antimicrobial Resistance Surveillance System suggest that variation of consumption coincides with the occurrence of resistance at the country level. Linear regression analysis showed that the association between antimicrobial drug use and resistance was specific and robust for 2 of 3 compound pathogen combinations, stable over time, but not sensitive enough to explain all of the observed variations. Ecologic studies based on routine surveillance data indicate a relation between use and resistance and support interventions designed to reduce antimicrobial drug consumption at a national level in Europe. PMID:18976555

  8. Antimicrobial resistance and prevalence of resistance genes of obligate anaerobes isolated from periodontal abscesses.

    PubMed

    Xie, Yi; Chen, Jiazhen; He, Junlin; Miao, Xinyu; Xu, Meng; Wu, Xingwen; Xu, Beiyun; Yu, Liying; Zhang, Wenhong

    2014-02-01

    This study attempts to determine the antimicrobial resistance profiles of obligate anaerobic bacteria that were isolated from a periodontal abscess and to evaluate the prevalence of resistance genes in these bacteria. Forty-one periodontal abscess samples were cultivated on selective and non-selective culture media to isolate the oral anaerobes. Their antibiotic susceptibilities to clindamycin, doxycycline, amoxicillin, imipenem, cefradine, cefixime, roxithromycin, and metronidazole were determined using the agar dilution method, and polymerase chain reaction assays were performed to detect the presence of the ermF, tetQ, nim, and cfxA drug resistance genes. A total of 60 different bacterial colonies was isolated and identified. All of the isolates were sensitive to imipenem. Of the strains, 6.7%, 13.3%, 16.7%, and 25% were resistant to doxycycline, metronidazole, cefixime, and amoxicillin, respectively. The resistance rate for both clindamycin and roxithromycin was 31.7%. Approximately 60.7% of the strains had the ermF gene, and 53.3% of the amoxicillin-resistant strains were found to have the cfxA gene. Two nim genes that were found in eight metronidazole-resistant strains were identified as nimB. In the present study, the Prevotella species are the most frequently isolated obligate anaerobes from periodontal abscesses. The current results show their alarmingly high resistance rate against clindamycin and roxithromycin; thus, the use of these antibiotics is unacceptable for the empirical therapy of periodontal abscesses. A brief prevalence of four resistance genes in the anaerobic bacteria that were isolated was also demonstrated.

  9. Hydrological modeling of fecal indicator bacteria in a tropical mountain catchment

    USDA-ARS?s Scientific Manuscript database

    The occurrence of pathogen bacteria in surface waters is a threat to public health worldwide. In particular, inadequate sanitation resulting in high contamination of surface water with pathogens of fecal origin is a serious issue in developing countries such as Lao P.D.R. Despite the health implicat...

  10. Update on antimicrobial resistance.

    PubMed

    Weber, Carol J

    2005-02-01

    WHO experts believe that antimicrobial resistance is potentially containable, but the window of opportunity to control and eventually eliminate the most dangerous infectious diseases is closing. If we miss our opportunity, it may become very difficult and expensive--and in some cases impossible--to treat infectious diseases. WHO's global strategy to contain antimicrobial resistance requires a massive effort and an alliance among countries, governments, international organizations, drug manufacturers, and private and public health care sectors. If infectious diseases are fought wisely and widely by the international community, drug resistance can be controlled and lives saved.

  11. Temporal trends and patterns in antimicrobial resistant Gram-negative bacteria implicated in intensive care unit-acquired infections: a cohort-based surveillance study in Istanbul, Turkey.

    PubMed

    Durdu, Bulent; Kritsotakis, Evangelos I; Lee, Andrew C K; Torun, Perihan; Hakyemez, Ismail N; Gultepe, Bilge; Aslan, Turan

    2018-05-08

    This study assessed trends and patterns in antimicrobial resistant intensive care unit (ICU)-acquired infections caused by Gram-negative bacteria (GNB) in Istanbul, Turkey. Bacterial culture and antibiotic susceptibility data were collected for all GNB causing nosocomial infections in five adult ICUs of a large university hospital during 2012-2015. Multi-resistance patterns were categorised as multidrug (MDR), extensively-drug (XDR) and pandrug (PDR)-resistance. Patterns and trends were assessed using seasonal decomposition and regression analyses. Of 991 pathogenic GNB recorded, most frequent were Acinetobacter baumannii (35%), Klebsiella species (27%), Pseudomonas aeruginosa (18%), Escherichia coli (7%) and Enterobacter species (4%). The overall infection rate decreased by 41% from 18.4 to 10.9 cases per 1000 patient-days in 2012 compared to 2015 (p <0.001), mostly representing decreases in bloodstream infections and pneumonias by A. baumannii and P. aeruginosa. XDR proportion in A.baumannii increased from 52% in 2012 to 72% in 2015, but only one isolate was colistin-resistant. Multi-resistance patterns remained stable in Klebsiella, with overall XDR and possible PDR proportions of 14% and 2%, respectively. A back-to-susceptibility trend was noted for P. aeruginosa in which the non-MDR proportion increased from 53% in 2012 to 71% in 2015. 88% of E.coli and 40% of Enterobacter isolates were MDR, but none was XDR. Antimicrobial resistance patterns in pathogenic GNB continuously change over time and may not reflect single-agent resistance trends. The proportionate amount of antimicrobial-resistant GNB may persist despite overall decreasing infection rates. Timely regional surveillance data are thus imperative for optimal infection control. Copyright © 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

  12. Synergistic antimicrobial therapy using nanoparticles and antibiotics for the treatment of multidrug-resistant bacterial infection

    NASA Astrophysics Data System (ADS)

    Gupta, Akash; Saleh, Neveen M.; Das, Riddha; Landis, Ryan F.; Bigdeli, Arafeh; Motamedchaboki, Khatereh; Rosa Campos, Alexandre; Pomeroy, Kenneth; Mahmoudi, Morteza; Rotello, Vincent M.

    2017-06-01

    Infections caused by multidrug-resistant (MDR) bacteria pose a serious global burden of mortality, causing thousands of deaths each year. Antibiotic treatment of resistant infections further contributes to the rapidly increasing number of antibiotic-resistant species and strains. Synthetic macromolecules such as nanoparticles (NPs) exhibit broad-spectrum activity against MDR species, however lack of specificity towards bacteria relative to their mammalian hosts limits their widespread therapeutic application. Here, we demonstrate synergistic antimicrobial therapy using hydrophobically functionalized NPs and fluoroquinolone antibiotics for treatment of MDR bacterial strains. An 8-16-fold decrease in antibiotic dosage is achieved in presence of engineered NPs to combat MDR strains. This strategy demonstrates the potential of using NPs to ‘revive’ antibiotics that have been rendered ineffective due to the development of resistance by pathogenic bacteria.

  13. Antimicrobial activity of the bioactive components of essential oils from Pakistani spices against Salmonella and other multi-drug resistant bacteria

    PubMed Central

    2013-01-01

    activities against selected multi drug resistant clinical and soil bacterial strains. Cinnamaldehyde was identified as the most active antimicrobial component present in the cinnamon essential oil which acted as a strong inhibitory agent in MIC assay against the tested bacteria. The results indicate that essential oils from Pakistani spices can be pursued against multidrug resistant bacteria. PMID:24119438

  14. Temporal Synchronization Analysis for Improving Regression Modeling of Fecal Indicator Bacteria Levels

    EPA Science Inventory

    Multiple linear regression models are often used to predict levels of fecal indicator bacteria (FIB) in recreational swimming waters based on independent variables (IVs) such as meteorologic, hydrodynamic, and water-quality measures. The IVs used for these analyses are traditiona...

  15. Antimicrobial resistance in Escherichia coli and Salmonella spp. isolates from fresh produce and the impact to food safety.

    PubMed

    Vital, Pierangeli G; Caballes, Marie Bernadine D; Rivera, Windell L

    2017-09-02

    Foodborne diseases associated with fresh produce consumption have escalated worldwide, causing microbial safety of produce of critical importance. Bacteria that have increasingly been detected in fresh produce are Escherichia coli and Salmonella spp., both of which have been shown to progressively display antimicrobial resistance. The study focused on the assessment of antimicrobial resistance of these enteric bacteria from different kinds of fresh produce from various open air markets and supermarkets in the Philippines. Using the disk diffusion assay on a total of 50 bacterial isolates obtained from 410 fresh produce surveyed, monoresistance to tetracycline was observed to be the most prevalent (38%), followed by multidrug resistance to tetracycline, chloramphenicol, ciprofloxacin, and nalidixic acid (4%), and lastly by dual resistance to tetracycline and chloramphenicol (2%). Using multiplex and simplex polymerase chain reaction (PCR) assays, tetA (75%) and tetB (9%) were found in tetracycline resistant isolates, whereas catI (67%) and catIII (33%) were detected in chloramphenicol resistant isolates. Sequence analysis of gyr and par genes from the ciprofloxacin and nalidixic acid resistant isolates revealed different mutations. Based on the results, fresh produce act as a reservoir of these antibiotic resistant bacteria which may pose health threat to consumers.

  16. Antimicrobial Resistance Genes in Pigeons from Public Parks in Costa Rica.

    PubMed

    Blanco-Peña, K; Esperón, F; Torres-Mejía, A M; de la Torre, A; de la Cruz, E; Jiménez-Soto, M

    2017-11-01

    Antimicrobial resistance is known to be an emerging problem, but the extent of the issue remains incomplete. The aim of this study was to determine the presence or absence of nine resistance genes (bla TEM , catI, mecA, qnrS, sulI, sulII, tet(A), tet(Q), vanA) in the faeces of 141 pigeons from four urban parks in Alajuela, Guadalupe, Tres Ríos and San José in Costa Rica. The genes were identified by real-time PCR directly from enema samples. About 30% of the samples were positive for genes catI and sulI; between 13% and 17% were positive for qnrS, sulII, tet(A) and tet(Q); and 4% were positive for bla TEM . The mecA and vanA genes were not detected. The average of antimicrobial resistance genes detected per pigeon was 2. Eight different patterns of resistance were identified, without differences in the sampling areas, being the most common pattern 2 (sulII positive samples). During rainy season, the genes more frequently found were sulI and tet(A). In conclusion, the urban inhabiting pigeons tested are currently carrying antimicrobial resistance genes, potentially acting as reservoirs of resistant bacteria and vectors to humans. To the authors' knowledge, this is the first study carried out on direct detection of resistance genes in the digestive metagenomes of pigeons. © 2017 The Authors. Zoonoses and Public Health Published by Blackwell Verlag GmbH.

  17. In Vivo Selection of Resistant E. coli after Ingestion of Milk with Added Drug Residues

    PubMed Central

    Pereira, Richard Van Vleck; Siler, Julie D.; Bicalho, Rodrigo Carvalho; Warnick, Lorin D.

    2014-01-01

    Antimicrobial resistance represents a major global threat to modern medicine. In vitro studies have shown that very low concentrations of drugs, as frequently identified in the environment, and in foods and water for human and animal consumption, can select for resistant bacteria. However, limited information is currently available on the in vivo impact of ingested drug residues. The objective of our study was to evaluate the effect of feeding preweaned calves milk containing antimicrobial drug residues (below the minimum inhibitory concentration), similar to concentrations detected in milk commonly fed to dairy calves, on selection of resistant fecal E. coli in calves from birth to weaning. At birth, thirty calves were randomly assigned to a controlled feeding trial where: 15 calves were fed raw milk with no drug residues (NR), and 15 calves were fed raw milk with drug residues (DR) by adding ceftiofur, penicillin, ampicillin, and oxytetracycline at final concentrations in the milk of 0.1, 0.005, 0.01, and 0.3 µg/ml, respectively. Fecal samples were rectally collected from each calf once a week starting at birth prior to the first feeding in the trial (pre-treatment) until 6 weeks of age. A significantly greater proportion of E. coli resistant to ampicillin, cefoxitin, ceftiofur, streptomycin and tetracycline was observed in DR calves when compared to NR calves. Additionally, isolates from DR calves had a significant decrease in susceptibility to ceftriaxone and ceftiofur when compared to isolates from NR calves. A greater proportion of E. coli isolates from calves in the DR group were resistant to 3 or more antimicrobial drugs when compared to calves in the ND group. These findings highlight the role that low concentrations of antimicrobial drugs have on the evolution and selection of resistance to multiple antimicrobial drugs in vivo. PMID:25506918

  18. Prevalence and characterization of antimicrobial-resistant Escherichia coli isolated from conventional and organic vegetables.

    PubMed

    Kim, Sara; Woo, Gun-Jo

    2014-10-01

    To compare the characteristics and to identify the epidemiological relationships of Escherichia coli isolated from organic and conventional vegetables, the antimicrobial resistance and genetic properties of E. coli were investigated from 2010 to 2011. E. coli was isolated from 1 of 111 (0.9%) organic vegetables and from 20 of 225 (8.9%) conventional vegetables. The majority of strains were isolated from the surrounding farming environment (n=27/150 vs. 49/97 in organic vs. conventional samples). The majority of the vegetable strains were isolated from the surrounding farming environments. E. coli isolated from organic vegetables showed very low antimicrobial resistance rates except for cephalothin, ranging from 0% to 17.9%, while the resistance rates to cephalothin (71%) were extremely high in both groups. E. coli isolates expressed various resistance genes, which most commonly included blaTEM, tet(A), strA, strB, and qnrS. However, none of the isolates harbored tet(D), tet(E), tet(K), tet(L), tet(M), or qnrA. The transferability of tet gene, tet(A), and tet(B) was identified in tetracycline-resistant E. coli, and the genetic relationship was confirmed in a few cases from different sources. With regard to the lower antimicrobial resistance found in organic produce, this production mode seems able to considerably reduce the selection of antimicrobial-resistant bacteria on vegetables.

  19. COMPARATIVE DIVERSITY OF FECAL BACTERIA IN AGRICULTURALLY SIGNIFICANT ANIMALS TO IDENTIFY ALTERNATIVE TARGETS FOR MICROBIAL SOURCE TRACKING

    EPA Science Inventory

    Animals of agricultural significance contribute a large percentage of fecal pollution to waterways via runoff contamination. The premise of microbial source tracking is to utilize fecal bacteria to identify target populations which are directly correlated to specific animal feces...

  20. Characterization of Escherichia coli Isolates from an Urban Lake Receiving Water from a Wastewater Treatment Plant in Mexico City: Fecal Pollution and Antibiotic Resistance.

    PubMed

    Rosas, Irma; Salinas, Eva; Martínez, Leticia; Cruz-Córdova, Ariadnna; González-Pedrajo, Bertha; Espinosa, Norma; Amábile-Cuevas, Carlos F

    2015-10-01

    The presence of enteric bacteria in water bodies is a cause of public health concerns, either by directly causing water- and food-borne diseases, or acting as reservoirs for antibiotic resistance determinants. Water is used for crop irrigation; and sediments and aquatic plants are used as fertilizing supplements and soil conditioners. In this work, the bacterial load of several micro-environments of the urban lake of Xochimilco, in Mexico City, was characterized. We found a differential distribution of enteric bacteria between the water column, sediment, and the rhizoplane of aquatic plants, with human fecal bacteria concentrating in the sediment, pointing to the need to assess such bacterial load for each micro-environment, for regulatory agricultural purposes, instead of only the one of the water, as is currently done. Resistance to tetracycline, ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole was common among Escherichia coli isolates, but was also differentially distributed, being again higher in sediment isolates. A distinct distribution of chloramphenicol minimum inhibitory concentrations (MIC) among these isolates suggests the presence of a local selective pressure favoring lower MICs than those of isolates from treated water. Fecal bacteria of human origin, living in water bodies along with their antibiotic resistance genes, could be much more common than typically considered, and pose a higher health risk, if assessments are only made on the water column of such bodies.

  1. Fecal-indicator bacteria in surface waters of the Santee River Basin and coastal drainages, North and South Carolina, 1995-98

    USGS Publications Warehouse

    Wilhelm, Lance J.; Maluk, Terry L.

    1998-01-01

    IntroductionHigh levels of fecal-indicator bacteria in rivers and streams can indicate the possible presence of pathogenic (disease-causing) microorganisms. Cholera, typhoid fever, bacterial dysentery, infectious hepatitis, and cryptosporidiosis are some of the well known waterborne diseases that spread through water contaminated and fecal matter. Eye, ear, nose, and throat infections also can result from contact with contaminated water. In general, methods are not routinely used to detect pathogens in water. Instead, bacteria such as total coliforms, fecal coliforms, fecal streptococci, Escherichia coli (E coli), and enterococci are used as indicators of sanitary water quality, because they are present in high numbers in fecal material and have been shown to be associated with some waterborne disease-causing organisms. Indicator bacteria usually are harmless, more plentiful, and easier to detect than pathogens. The concentration of bacteria in a sample of water is usually expressed as the number of bacterial colonies per 100 milliliters of water sample.As part of the U.S. Geological Survey National Water-Quality Assessment Program, 145 samples were collected and analyzed for selected water-quality constituents, fecal coliforms, and fecal streptococci at 17 sites in North and South Carolina from October 1995 through September 1996. Of the original 17 sites, 4 in South Carolina were sampled for E. coli and total coliforms from April through September 1997. At two sites, this sampling continued from October 1997 through April 1998.

  2. Functional synergy of α-helical antimicrobial peptides and traditional antibiotics against Gram-negative and Gram-positive bacteria in vitro and in vivo.

    PubMed

    Feng, Q; Huang, Y; Chen, M; Li, G; Chen, Y

    2015-01-01

    In this study, the antimicrobial activities based on the synergistic effects of traditional antibiotics (imipenem, cefepime, levofloxacin hydrochloride and vancomycin) and antimicrobial peptides (AMPs; PL-5, PL-31, PL-32, PL-18, PL-29 and PL-26), alone or in combination, against three Gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumoniae and Staphylococcus epidermidis) and three Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae) were investigated. In addition, the antimicrobial activity that was based on the synergistic effects of levofloxacin hydrochloride and PL-5 against Staphylococcus aureus in vivo was explored in a mouse infection model. Traditional antibiotics and AMPs showed significant synergistic effects on the antibacterial activities against the different Gram-positive and Gram-negative bacteria in vitro. A strong synergistic effect in the PL-5 and levofloxacin hydrochloride combination against Staphylococcus aureus was observed in the mouse infection model in vivo. The mechanism of synergistic action was due to the different targets of AMPs and traditional antibiotics. The combination of AMPs and traditional antibiotics can dramatically enhance antimicrobial activity and may help prevent or delay the emergence of antibiotic resistance. Thus, this combination therapy could be a promising approach to treat bacterial infections, particularly mixed infections and multi-antibiotic-resistant infections, in the clinics.

  3. The Rising Tide of Antimicrobial Resistance in Aquaculture: Sources, Sinks and Solutions

    PubMed Central

    Watts, Joy E. M.; Schreier, Harold J.; Lanska, Lauma; Hale, Michelle S.

    2017-01-01

    As the human population increases there is an increasing reliance on aquaculture to supply a safe, reliable, and economic supply of food. Although food production is essential for a healthy population, an increasing threat to global human health is antimicrobial resistance. Extensive antibiotic resistant strains are now being detected; the spread of these strains could greatly reduce medical treatment options available and increase deaths from previously curable infections. Antibiotic resistance is widespread due in part to clinical overuse and misuse; however, the natural processes of horizontal gene transfer and mutation events that allow genetic exchange within microbial populations have been ongoing since ancient times. By their nature, aquaculture systems contain high numbers of diverse bacteria, which exist in combination with the current and past use of antibiotics, probiotics, prebiotics, and other treatment regimens—singularly or in combination. These systems have been designated as “genetic hotspots” for gene transfer. As our reliance on aquaculture grows, it is essential that we identify the sources and sinks of antimicrobial resistance, and monitor and analyse the transfer of antimicrobial resistance between the microbial community, the environment, and the farmed product, in order to better understand the implications to human and environmental health. PMID:28587172

  4. Antibacterial clay against gram-negative antibiotic resistant bacteria.

    PubMed

    Zarate-Reyes, Luis; Lopez-Pacheco, Cynthia; Nieto-Camacho, Antonio; Palacios, Eduardo; Gómez-Vidales, Virginia; Kaufhold, Stephan; Ufer, Kristian; García Zepeda, Eduardo; Cervini-Silva, Javiera

    2018-01-15

    Antibiotic resistant bacteria persist throughout the world because they have evolved the ability to express various defense mechanisms to cope with antibiotics and the immune system; thus, low-cost strategies for the treatment of these bacteria are needed, such as the usage of environmental minerals. This paper reports the antimicrobial properties of a clay collected from Brunnenberg, Germany, that is composed of ferroan saponite with admixtures of quartz, feldspar and calcite as well as exposed or hidden (layered at inner regions) nano Fe(0). Based on the growth curves (log phase) of six antibiotic resistant bacteria (4 gram-negative and 2 gram-positive), we concluded that the clay acted as a bacteriostat; however, the clay was only active against the gram-negative bacteria (except for resilient Klebsiella pneumonia). The bacteriostatic mode of action was evidenced by the initial lack of Colony Forming Units on agar plates with growth registered afterward, certainly after 24h, and can be explained because interactions between membrane lipopolysaccharides and the siloxane surfaces of the clay. Labile or bioavailable Fe in the clay (extracted by EDTA or DFO-B) induced the quantitative production of HO as well as oxidative stress, which, nevertheless, did not account for by its bacteriostatic activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Molecular Design, Structures, and Activity of Antimicrobial Peptide-Mimetic Polymers

    PubMed Central

    Takahashi, Haruko; Palermo, Edmund F.; Yasuhara, Kazuma; Caputo, Gregory A.

    2014-01-01

    There is an urgent need for new antibiotics which are effective against drug-resistant bacteria without contributing to resistance development. We have designed and developed antimicrobial copolymers with cationic amphiphilic structures based on the mimicry of naturally occurring antimicrobial peptides. These copolymers exhibit potent antimicrobial activity against a broad spectrum of bacteria including methicillin-resistant Staphylococcus aureus with no adverse hemolytic activity. Notably, these polymers also did not result in any measurable resistance development in E. coli. The peptide-mimetic design principle offers significant flexibility and diversity in the creation of new antimicrobial materials and their potential biomedical applications. PMID:23832766

  6. Antimicrobial use in food and companion animals.

    PubMed

    Prescott, John F

    2008-12-01

    The vast literature on antimicrobial drug use in animals has expanded considerably recently as the antimicrobial resistance (AMR) crisis in human medicine leads to questions about all usage of antimicrobial drugs, including long-term usage in intensively managed food animals for growth promotion and disease prevention. Attention is also increasingly focusing on antimicrobial use and on bacterial resistance in companion animals, which are in intimate contact with the human population. They may share resistant bacteria with their owners, amplify resistant bacteria acquired from their owners, and act as a reservoir for human infection. Considerable effort is being made to describe the basis of AMR in bacterial pathogens of animals. Documentation of many aspects of use of antimicrobials in animals is, however, generally less developed and only a few countries can describe quantities of drugs used in animals to kg levels annually. In recent years, many national veterinary associations have produced 'prudent use guidelines' to try to improve antimicrobial drug use and decrease resistance, but the impact of guidelines is unknown. Within the evolving global movement for 'antimicrobial stewardship', there is considerable scope to improve many aspects of antimicrobial use in animals, including infection control and reduction of use, with a view to reducing resistance and its spread, and to preserving antimicrobial drugs for the future.

  7. Frequency and antimicrobial susceptibility of gram-negative bacteria isolated from 2 hospitals in Makkah, Saudi Arabia.

    PubMed

    Asghar, Atif H; Faidah, Hani S

    2009-08-01

    To estimate the prevalence and antibiotic susceptibility of the gram-negative bacteria isolated from 2 hospitals in Makkah. This study was undertaken in 2 main tertiary care hospitals namely; Al-Noor Specialist Hospital, and Hera Hospital in Makkah, Kingdom of Saudi Arabia from October 2005 to March 2006. A total of 1137 gram-negative bacteria were identified in non-duplicate clinical specimens obtained from 965 patients of various body sites infections. Demographic data, identity of microorganisms, and antimicrobial susceptibilities were obtained from medical and laboratory records. The most prevalent gram-negative bacteria were Escherichia coli (31.6%), and Pseudomonas aeruginosa (31.2%), followed by Acinetobacter baumannii (10.8%), Klebsiella pneumoniae (8.3%), Klebsiella sp. (6.2%), Haemophilus influenzae (3.7%), Proteus sp. (3.3%), and Enterobacter sp. (1.9%). Results demonstrated that gram-negative bacteria have a high rate of resistance to commonly used antibiotics. Furthermore, multi-drug resistance was also common in this study. Our data showed a high rate of resistance among gram-negative pathogens in comparison with other countries in the world. The implementation of monitoring programs is an important part of the prevention strategy against the development of antibiotic resistance in hospitals.

  8. Antimicrobial resistance trends among Salmonella isolates obtained from dairy cattle in the northeastern United States, 2004-2011.

    PubMed

    Cummings, Kevin J; Perkins, Gillian A; Khatibzadeh, Sarah M; Warnick, Lorin D; Altier, Craig

    2013-04-01

    Monitoring antimicrobial resistance trends among bacteria isolated from food animals and people is necessary to inform public policy regarding appropriate antimicrobial use. Our objectives were to describe the antimicrobial resistance status of Salmonella isolates from dairy cattle in the northeastern United States and to identify trends in resistance to various antimicrobial agents over time. Data were collected retrospectively for all bovine Salmonella isolates that were obtained from samples submitted to Cornell University's Animal Health Diagnostic Center between January 1, 2004 and December 31, 2011. Temporal trends in the prevalence of resistant Salmonella were investigated for each antimicrobial agent using the Cochran-Armitage trend test. Antimicrobial susceptibility testing was performed on 2745 bovine Salmonella isolates from clinical samples submitted during the study period. Overall resistance to each antimicrobial agent ranged from 0% (amikacin, ciprofloxacin, and nalidixic acid) to 72.0% (sulfadimethoxine). There was evidence of a significantly decreasing trend in prevalence of resistance to most agents: amoxicillin/clavulanic acid (AUG), ampicillin (AMP), cefoxitin (FOX), ceftiofur (TIO), ceftriaxone (AXO), chloramphenicol (CHL), chlortetracycline (CTET), florfenicol (FFN), kanamycin (KAN), neomycin (NEO), oxytetracycline (OXY), spectinomycin (SPE), streptomycin (STR), sulfadimethoxine (SDM), sulfisoxazole (FIS), and tetracycline (TET). Among the 265 isolates that were tested using the National Antimicrobial Resistance Monitoring System (NARMS) panel, the most common resistance patterns were pansusceptible (54.0%), AUG-AMP-FOX-TIO-AXO-CHL-KAN-STR-FIS-TET (18.1%), and AUG-AMP-FOX-TIO-AXO-CHL-STR-FIS-TET (12.1%). Increasing prevalence of S. enterica serovar Cerro over the course of the study period presumably had an impact on the observed resistance trends. Nevertheless, these results do not support the notion that the current level of antimicrobial

  9. High prevalence of antimicrobial resistance among Shigella isolates in the United States tested by the National Antimicrobial Resistance Monitoring System from 1999 to 2002.

    PubMed

    Sivapalasingam, Sumathi; Nelson, Jennifer M; Joyce, Kevin; Hoekstra, Mike; Angulo, Frederick J; Mintz, Eric D

    2006-01-01

    Shigella spp. infect approximately 450,000 persons annually in the United States, resulting in over 6,000 hospitalizations. Since 1999, the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria has tested every 10th Shigella isolate from 16 state or local public health laboratories for susceptibility to 15 antimicrobial agents. From 1999 to 2002, NARMS tested 1,604 isolates. Among 1,598 isolates identified to species level, 1,278 (80%) were Shigella sonnei, 295 (18%) were Shigella flexneri, 18 (1%) were Shigella boydii, and 7 (0.4%) were Shigella dysenteriae. Overall, 1,251 (78%) were resistant to ampicillin and 744 (46%) were resistant to trimethoprim-sulfamethoxazole (TMP-SMX). Prevalence of TMP-SMX- or ampicillin- and TMP-SMX-resistant Shigella sonnei isolates varied by geographic region, with lower rates in the South and Midwest regions (TMP-SMX resistance, 27% and 30%, respectively; ampicillin and TMP-SMX resistance, 25% and 22%, respectively) and higher rates in the East and West regions (TMP-SMX resistance, 66% and 80%, respectively; ampicillin and TMP-SMX resistance, 54% and 65%, respectively). Nineteen isolates (1%) were resistant to nalidixic acid (1% of S. sonnei and 2% of S. flexneri isolates); 12 (63%) of these isolates had decreased susceptibility to ciprofloxacin. One S. flexneri isolate was resistant to ciprofloxacin. All isolates were susceptible to ceftriaxone. Since 1986, resistance to ampicillin and TMP-SMX has dramatically increased. Shigella isolates in the United States remain susceptible to ciprofloxacin and ceftriaxone.

  10. High Prevalence of Antimicrobial Resistance among Shigella Isolates in the United States Tested by the National Antimicrobial Resistance Monitoring System from 1999 to 2002

    PubMed Central

    Sivapalasingam, Sumathi; Nelson, Jennifer M.; Joyce, Kevin; Hoekstra, Mike; Angulo, Frederick J.; Mintz, Eric D.

    2006-01-01

    Shigella spp. infect approximately 450,000 persons annually in the United States, resulting in over 6,000 hospitalizations. Since 1999, the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria has tested every 10th Shigella isolate from 16 state or local public health laboratories for susceptibility to 15 antimicrobial agents. From 1999 to 2002, NARMS tested 1,604 isolates. Among 1,598 isolates identified to species level, 1,278 (80%) were Shigella sonnei, 295 (18%) were Shigella flexneri, 18 (1%) were Shigella boydii, and 7 (0.4%) were Shigella dysenteriae. Overall, 1,251 (78%) were resistant to ampicillin and 744 (46%) were resistant to trimethoprim-sulfamethoxazole (TMP-SMX). Prevalence of TMP-SMX- or ampicillin- and TMP-SMX-resistant Shigella sonnei isolates varied by geographic region, with lower rates in the South and Midwest regions (TMP-SMX resistance, 27% and 30%, respectively; ampicillin and TMP-SMX resistance, 25% and 22%, respectively) and higher rates in the East and West regions (TMP-SMX resistance, 66% and 80%, respectively; ampicillin and TMP-SMX resistance, 54% and 65%, respectively). Nineteen isolates (1%) were resistant to nalidixic acid (1% of S. sonnei and 2% of S. flexneri isolates); 12 (63%) of these isolates had decreased susceptibility to ciprofloxacin. One S. flexneri isolate was resistant to ciprofloxacin. All isolates were susceptible to ceftriaxone. Since 1986, resistance to ampicillin and TMP-SMX has dramatically increased. Shigella isolates in the United States remain susceptible to ciprofloxacin and ceftriaxone. PMID:16377666

  11. Antimicrobial blue light inactivation of Methicillin-resistant Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Wang, Yucheng; Dai, Tianhong; Gu, Ying

    2016-10-01

    Background: With the increasing emergence of multidrug-resistant (MDR) bacterial strains, there is a pressing need for the development of alternative treatment for infections. Antimicrobial blue light (aBL) has provided a simple and effective approach. Methods: We first investigated the effectiveness of aBL (415 nm) inactivation of USA300 LAClux (a communityacquired Methicillin-resistant Staphylococcus aureus strain) both in the planktonic and biofilm forms. The survival of the bacteria in suspensions was determined by serial dilution and that of the biofilm-embedded bacteria was determined by bioluminescence quantification. Using a mouse model of thermal burn infected with USA300 LAClux, we further assessed the effectiveness of aBL for treating localized infections. Bioluminescence imaging was performed to monitor in real time bacterial viability in vivo. Results: In vitro study showed that, for the planktonic counterpart of the bacteria or the 24-h-old biofilms, an irradiance of 55 mW/cm2 for 60 min resulted in a 4.61 log10 or 2.56 log10 inactivation, respectively. In vivo study using infected mouse burns demonstrated that a 2.56-log10 inactivation was achieved after 100-mW/cm2 irradiation for 62 min. Conclusions: aBL is a potential alternative approach for treating Methicillin-resistant Staphylococcus aureus infections.

  12. Salmonella and fecal indicator bacteria survival in soils amended with poultry manure

    USDA-ARS?s Scientific Manuscript database

    Minimizing the risks associated with manure-borne pathogenic microorganisms requires an understanding of microbial survival under realistic field conditions. The objective of this 3-year study was to assess the fate of Salmonella (SALM) and fecal indicator bacteria (FIB), E. coli (EC) and enterococc...

  13. Prevalence and Antimicrobial Resistance of Enterobacteriaceae in Shell Eggs from Small-Scale Poultry Farms and Farmers' Markets.

    PubMed

    Kilonzo-Nthenge, A; Nahashon, S N; Godwin, S; Liu, S; Long, D

    2016-12-01

    Public health concerns over the emergence of antimicrobial resistant bacteria have increased recently. The purpose of this study was to investigate the prevalence of antimicrobial resistant Enterobacteriaceae in shell eggs purchased from small poultry farms and farmers' markets. A total of 504 eggs were pooled to make 252 composite samples, consisting of 2 eggs per composite. The microbial quality of shell eggs was determined by standard quantitative, biochemical, and PCR techniques. Susceptibility to 13 antimicrobial agents was determined by the Kirby-Bauer disk diffusion technique, and results were interpreted based on Clinical and Laboratory Standards Institute values. Shell eggs and egg contents were positive for Escherichia coli (11.9 and 5.2%, respectively), Enterobacter (9.1 and 7.9%), and Serratia (11.5 and 4.8%). Salmonella was isolated from 3.6% of egg shells but not from egg contents. Mean (±SD) Enterobacteriaceae levels (4.4 ± 2.0 log CFU per eggshell) on shell eggs from poultry farms was significantly higher (P ≤ 0.05) than that on shell eggs from farmers' markets (2.1 ± 1.3 log CFU per eggshell). Of the 134 isolates recovered, resistance among isolates from farm and market shell eggs to erythromycin was most common (48.5 and 32.8%, respectively) followed by ampicillin (44.8 and 17.2%), and tetracycline (29.9 and 17.2%). The multiple antibiotic resistance index value for E. coli and Pantoea was 0.62, and that for Salmonella and Klebsiella terrigena was 0.08, indicating that Enterobacteriaceae in shell eggs can be resistant to multiple antimicrobial agents. These data reveal that shell eggs from small poultry farms and farmers' markets can harbor antimicrobial resistant pathogenic and commensal bacteria. Thus, failure to properly handle shell eggs poses a potential health hazard to consumers.

  14. Antimicrobial effects of a new therapeutic liquid dentifrice formulation on oral bacteria including odorigenic species.

    PubMed

    Sreenivasan, P K; Furgang, D; Zhang, Y; DeVizio, W; Fine, D H

    2005-03-01

    The control of oral malodor is well-recognized in efforts to improve oral health. Antimicrobial formulations can mitigate oral malodor, however, procedures to assess effects on oral bacteria including those implicated in halitosis are unavailable. This investigation examined the antimicrobial effects of a new liquid triclosan/copolymer dentifrice (test) formulation that demonstrated significant inhibition of oral malodor in previous organoleptic clinical studies. Procedures compared antimicrobial effects of the test and control formulations on a range of oral micro-organisms including members implicated in halitosis, substantive antimicrobial effects of formulations with hydroxyapatite as a surrogate for human teeth and ex vivo effects on oral bacteria from human volunteers. With Actinomyces viscosus, as a model system, the test formulation demonstrated a dose-dependent effect. At these concentrations the test formulation provided significant antimicrobial effects on 13 strains of oral bacteria including those implicated in bad breath at selected posttreatment time points. Treatment of hydroxyapatite by the test dentifrice resulted in a significant and substantive antimicrobial effect vs. controls. Oral bacteria from subjects treated ex vivo with the test dentifrice resulted in significant reductions in cultivable oral bacteria and odorigenic bacteria producing hydrogen sulfide. In summary, microbiological methods adapted to study odorigenic bacteria demonstrate the significant antimicrobial effects of the test (triclosan/copolymer) dentifrice with laboratory and clinical strains of oral bacteria implicated in bad breath.

  15. Phytochemical, toxicological and antimicrobial evaluation of lawsonia inermis extracts against clinical isolates of pathogenic bacteria

    PubMed Central

    2013-01-01

    Background The emerging resistance of pathogen against the currently available antimicrobial agents demands the search of new antimicrobial agents. The use of medicinal plants as natural substitute is the paramount area of research to overwhelm the drug resistance of infectious agents. Scientists have not made enough effort on the evaluation of safety of medicinal plant yet. Methods In the present study antimicrobial activity of Lawsonia inermis is investigated against clinical isolates of seven bacteria including four Gram negative (Escherichia coli, Salmonella typhi, Klebsiella spp., Shigella sonnei) and three Gram positive (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis) using disc diffusion method. Four types of Lawsonia inermis extracts were prepared using methanol, chloroform, acetone and water as extraction solvents, while DMSO (Dimethyl sulfoxide) and water as dissolution solvents. The rate and extent of bacterial killing was estimated by time-kill kinetic assay at 1× MIC of each bacterial isolate. The overall safety of Lawsonia inermis extracts was assessed in mice. Results Lawsonia inermis displayed noteworthy antimicrobial activity against both gram positive and gram negative bacterial strains used in the study. The minimum value of MIC for different bacterial strains ranged from 2.31 mg/ml to 9.27 mg/ml. At 1x MIC of each bacterial isolate, 3log10 decrease in CFU was recorded after 6 hours of drug exposure and no growth was observed in almost all tested bacteria after 24 hours of exposure. No sign of toxidrome were observed during in vivo toxicity evaluation in mice at 300 mg/kg concentration. Conclusion In conclusion, the present study provides the scientific rational for medicinal use of Lawsonia inermis. The use of Lawsonia inermis extracts is of great significance as substitute antimicrobial agent in therapeutics. PMID:24289297

  16. Phytochemical, toxicological and antimicrobial evaluation of Lawsonia inermis extracts against clinical isolates of pathogenic bacteria.

    PubMed

    Gull, Iram; Sohail, Maria; Aslam, Muhammad Shahbaz; Amin Athar, Muhammad

    2013-12-01

    The emerging resistance of pathogen against the currently available antimicrobial agents demands the search of new antimicrobial agents. The use of medicinal plants as natural substitute is the paramount area of research to overwhelm the drug resistance of infectious agents. Scientists have not made enough effort on the evaluation of safety of medicinal plant yet. In the present study antimicrobial activity of Lawsonia inermis is investigated against clinical isolates of seven bacteria including four Gram negative (Escherichia coli, Salmonella typhi, Klebsiella spp., Shigella sonnei) and three Gram positive (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis) using disc diffusion method. Four types of Lawsonia inermis extracts were prepared using methanol, chloroform, acetone and water as extraction solvents, while DMSO (Dimethyl sulfoxide) and water as dissolution solvents. The rate and extent of bacterial killing was estimated by time-kill kinetic assay at 1× MIC of each bacterial isolate. The overall safety of Lawsonia inermis extracts was assessed in mice. Lawsonia inermis displayed noteworthy antimicrobial activity against both gram positive and gram negative bacterial strains used in the study. The minimum value of MIC for different bacterial strains ranged from 2.31 mg/ml to 9.27 mg/ml. At 1x MIC of each bacterial isolate, 3log10 decrease in CFU was recorded after 6 hours of drug exposure and no growth was observed in almost all tested bacteria after 24 hours of exposure. No sign of toxidrome were observed during in vivo toxicity evaluation in mice at 300 mg/kg concentration. In conclusion, the present study provides the scientific rational for medicinal use of Lawsonia inermis. The use of Lawsonia inermis extracts is of great significance as substitute antimicrobial agent in therapeutics.

  17. Macromolecular agents with antimicrobial potentialities: A drive to combat antimicrobial resistance.

    PubMed

    Bilal, Muhammad; Rasheed, Tahir; Iqbal, Hafiz M N; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

    2017-10-01

    In recent years, the antimicrobial resistance (AMR) or multidrug resistance (MDR) has become a serious health concern and major challenging issue, worldwide. After decades of negligence, the AMR has now captured global attention. The increasing number of antibiotic-resistant strains has threatened the achievements of science and medicine since it inactivates conventional antimicrobial therapeutics. Scientists are trying to respond to AMR/MDR threat by exploring innovative platforms and new therapeutic strategies to tackle infections from these resistant strains and bypass treatment limitations related to these pathologies. The present review focuses on the utilization of bio-inspired novel constructs and their potential applications as novel antimicrobial agents. The first part of the review describes plant-based biological macromolecules containing an immense variety of secondary metabolites, which could be potentially used as alternative strategies to combat antimicrobial resistance. The second part discusses the potential of metal-based macromolecules as effective antimicrobial platforms for preventing infections from resistant strains. The third part comprehensively elucidates how nanoparticles, in particular, metal-integrated nanoparticles can overcome this AMR or MDR issue. Towards the end, information is given with critical concluding remarks, gaps, and finally envisioned with future considerations. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Antimicrobial resistance in Libya: 1970-2011.

    PubMed

    Ghenghesh, Khalifa Sifaw; Rahouma, Amal; Tawil, Khaled; Zorgani, Abdulaziz; Franka, Ezzedin

    2013-03-27

    Resistance to antimicrobial agents is a major health problem that affects the whole world. Providing information on the past state of antimicrobial resistance in Libya may assist the health authorities in addressing the problem more effectively in the future. Information was obtained mainly from Highwire Press (including PubMed) search for the period 1970-2011 using the terms 'antibiotic resistance in Libya', 'antimicrobial resistance in Libya', 'tuberculosis in Libya', and 'primary and acquired resistance in Libya' in title and abstract. From 1970 to 2011 little data was available on antimicrobial resistance in Libya due to lack of surveillance and few published studies. Available data shows high resistance rates for Salmonella species in the late 1970s and has remained high to the present day. High prevalence rates (54-68%) of methicillin-resistant Staphylococcus aureus (MRSA) were reported in the last decade among S. aureus from patients with burns and surgical wound infections. No reports were found of vancomycin-resistant S. aureus (VRSA) or vancomycin-intermediate-resistant S. aureus (VISA) using standard methods from Libya up to the end of 2011. Reported rates of primary (i.e. new cases) and acquired (i.e. retreatment cases) multidrug-resistant tuberculosis (MDR-TB) from the eastern region of Libya in 1971 were 16.6 and 33.3% and in 1976 were 8.6 and 14.7%, in western regions in 1984-1986 were 11 and 21.5% and in the whole country in 2011 were estimated at 3.4 and 29%, respectively. The problem of antibiotic resistance is very serious in Libya. The health authorities in particular and society in general should address this problem urgently. Establishing monitoring systems based on the routine testing of antimicrobial sensitivity and education of healthcare workers, pharmacists, and the community on the health risks associated with the problem and benefits of prudent use of antimicrobials are some steps that can be taken to tackle the problem in the future.

  19. Antimicrobial resistance in Libya: 1970-2011.

    PubMed

    Sifaw Ghenghesh, Khalifa; Rahouma, Amal; Tawil, Khaled; Zorgani, Abdulaziz; Franka, Ezzedin

    2013-01-01

    Resistance to antimicrobial agents is a major health problem that affects the whole world. Providing information on the past state of antimicrobial resistance in Libya may assist the health authorities in addressing the problem more effectively in the future. Information was obtained mainly from Highwire Press (including PubMed) search for the period 1970-2011 using the terms 'antibiotic resistance in Libya', 'antimicrobial resistance in Libya', 'tuberculosis in Libya', and 'primary and acquired resistance in Libya' in title and abstract. From 1970 to 2011 little data was available on antimicrobial resistance in Libya due to lack of surveillance and few published studies. Available data shows high resistance rates for Salmonella species in the late 1970s and has remained high to the present day. High prevalence rates (54-68%) of methicillin-resistant Staphylococcus aureus (MRSA) were reported in the last decade among S. aureus from patients with burns and surgical wound infections. No reports were found of vancomycin-resistant S. aureus (VRSA) or vancomycin-intermediate-resistant S. aureus (VISA) using standard methods from Libya up to the end of 2011. Reported rates of primary (i.e. new cases) and acquired (i.e. retreatment cases) multidrug-resistant tuberculosis (MDR-TB) from the eastern region of Libya in 1971 were 16.6 and 33.3% and in 1976 were 8.6 and 14.7%, in western regions in 1984-1986 were 11 and 21.5% and in the whole country in 2011 were estimated at 3.4 and 29%, respectively. The problem of antibiotic resistance is very serious in Libya. The health authorities in particular and society in general should address this problem urgently. Establishing monitoring systems based on the routine testing of antimicrobial sensitivity and education of healthcare workers, pharmacists, and the community on the health risks associated with the problem and benefits of prudent use of antimicrobials are some steps that can be taken to tackle the problem in the future.

  20. Community Structures of Fecal Bacteria in Cattle from Different Animal Feeding Operations▿†

    PubMed Central

    Shanks, Orin C.; Kelty, Catherine A.; Archibeque, Shawn; Jenkins, Michael; Newton, Ryan J.; McLellan, Sandra L.; Huse, Susan M.; Sogin, Mitchell L.

    2011-01-01

    The fecal microbiome of cattle plays a critical role not only in animal health and productivity but also in food safety, pathogen shedding, and the performance of fecal pollution detection methods. Unfortunately, most published molecular surveys fail to provide adequate detail about variability in the community structures of fecal bacteria within and across cattle populations. Using massively parallel pyrosequencing of a hypervariable region of the rRNA coding region, we profiled the fecal microbial communities of cattle from six different feeding operations where cattle were subjected to consistent management practices for a minimum of 90 days. We obtained a total of 633,877 high-quality sequences from the fecal samples of 30 adult beef cattle (5 individuals per operation). Sequence-based clustering and taxonomic analyses indicate less variability within a population than between populations. Overall, bacterial community composition correlated significantly with fecal starch concentrations, largely reflected in changes in the Bacteroidetes, Proteobacteria, and Firmicutes populations. In addition, network analysis demonstrated that annotated sequences clustered by management practice and fecal starch concentration, suggesting that the structures of bovine fecal bacterial communities can be dramatically different in different animal feeding operations, even at the phylum and family taxonomic levels, and that the feeding operation is a more important determinant of the cattle microbiome than is the geographic location of the feedlot. PMID:21378055

  1. In vitro antimicrobial activity of five essential oils on multidrug resistant Gram-negative clinical isolates.

    PubMed

    Sakkas, Hercules; Gousia, Panagiota; Economou, Vangelis; Sakkas, Vassilios; Petsios, Stefanos; Papadopoulou, Chrissanthy

    2016-01-01

    The emergence of drug-resistant pathogens has drawn attention on medicinal plants for potential antimicrobial properties. The objective of the present study was the investigation of the antimicrobial activity of five plant essential oils on multidrug resistant Gram-negative bacteria. Basil, chamomile blue, origanum, thyme, and tea tree oil were tested against clinical isolates of Acinetobacter baumannii (n = 6), Escherichia coli (n = 4), Klebsiella pneumoniae (n = 7), and Pseudomonas aeruginosa (n = 5) using the broth macrodilution method. The tested essential oils produced variable antibacterial effect, while Chamomile blue oil demonstrated no antibacterial activity. Origanum, Thyme, and Basil oils were ineffective on P. aeruginosa isolates. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values ranged from 0.12% to 1.50% (v/v) for tea tree oil, 0.25-4% (v/v) for origanum and thyme oil, 0.50% to >4% for basil oil and >4% for chamomile blue oil. Compared to literature data on reference strains, the reported MIC values were different by 2SD, denoting less successful antimicrobial activity against multidrug resistant isolates. The antimicrobial activities of the essential oils are influenced by the strain origin (wild, reference, drug sensitive, or resistant) and it should be taken into consideration whenever investigating the plants' potential for developing new antimicrobials.

  2. Antimicrobial-resistant Invasive Escherichia coli, Spain

    PubMed Central

    Oteo, Jesús; Lázaro, Edurne; de Abajo, Francisco J.; Baquero, Fernando; Campos, José

    2005-01-01

    To address the public health problem of antimicrobial resistance, the European Union founded the European Antimicrobial Resistance Surveillance System. A network of 32 Spanish hospitals, serving ≈9.6 million persons, submitted antimicrobial-susceptibility data on 7,098 invasive Escherichia coli species (2001–2003). Resistance to ampicillin, cotrimoxazole, ciprofloxacin, gentamicin, and tobramycin was found at rates of 59.9%, 32.6%, 19.3%, 6.8%, and 5.3%, respectively. Resistance to multiple drugs increased from 13.8% in 2001 to 20.6% in 2003 (p <0.0001). Antimicrobial consumption data were obtained from the Spanish National Health System. In spite of decreased cephalosporin and β-lactam use, overall extended-spectrum β-lactamase production increased from 1.6% (2001) to 4.1% (2003) (p <0.0001), mainly due to the rising prevalence of cefotaximases. Resistance to ciprofloxacin significantly increased, mostly in community-onset infections, which coincided with a rise in community quinolone use. Cotrimoxazole resistance remained stable at ≈30%, even though its use was dramatically reduced. PMID:15829192

  3. Adjuvant strategies for potentiation of antibiotics to overcome antimicrobial resistance.

    PubMed

    Pieren, Michel; Tigges, Marcel

    2012-10-01

    Alarming facts about the occurrence and spreading of multiple antibiotic resistant bacteria have caught the attention of global surveillance authorities and public media. The demand for novel effective antimicrobial drugs is high and on the rise while, at the same time, the supply of fresh 'magic bullets' is drying up. This review summarizes examples of recent strategies for development of adjunctive antibiotic therapies that overcome microbial resistance and thus rejuvenate the existing arsenal of drugs. Recent studies have demonstrated the potential of compounds that inhibit the action of the repressor protein implicated in ethionamide resistance, thus stimulating activation of the drug and thereby restoring the activity of the antibiotic for treatment of Mycobacterium tuberculosis. Such specific interference with regulators or signal transduction mechanisms involved in antibiotic resistance or virulence provides a new toolbox for novel combinations of antimicrobial drugs with adjuvant molecules lacking intrinsic antibiotic activity. In addition to the development of new antibiotics and vaccination initiatives this strategy of restoring or potentiating the activity of existing antibiotics may help to postpone the day when antibiotics are no longer generally efficacious. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. [First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans/ Anaerobic Subcommittee of the Asociación Argentina de Microbiología].

    PubMed

    Legaria, María C; Bianchini, Hebe M; Castello, Liliana; Carloni, Graciela; Di Martino, Ana; Fernández Canigia, Liliana; Litterio, Mirta; Rollet, Raquel; Rossetti, Adelaida; Predari, Silvia C

    2011-01-01

    Through time, anaerobic bacteria have shown good susceptibility to clinically useful antianaerobic agents. Nevertheless, the antimicrobial resistance profile of most of the anaerobic species related to severe infections in humans has been modified in the last years and different kinds of resistance to the most active agents have emerged, making their effectiveness less predictable. With the aim of finding an answer and for the purpose of facilitating the detection of anaerobic antimicrobial resistance, the Anaerobic Subcommittee of the Asociación Argentina de Microbiología developed the First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans. This document resulted from the compatibilization of the Clinical and Laboratory Standards Institute recommendations, the international literature and the work and experience of the Subcommittee. The Consensus document provides a brief taxonomy review, and exposes why and when anaerobic antimicrobial susceptibility tests should be conducted, and which antimicrobial agents can be used according to the species involved. The recommendations on how to perform, read and interpret in vitro anaerobic antimicrobial susceptibility tests with each method are exposed. Finally, the antibiotic susceptibility profile, the classification of antibiotics according to their in vitro activities, the natural and acquired mechanisms of resistance, the emerging resistance and the regional antibiotic resistance profile of clinically relevant anaerobic species are shown.

  5. Antimicrobial resistance and serotype prevalence of Salmonella isolated from dairy cattle in the southwestern United States.

    PubMed

    Edrington, T S; Schultz, C L; Bischoff, K M; Callaway, T R; Looper, M L; Genovese, K J; Jung, Y S; McReynolds, J L; Anderson, R C; Nisbet, D J

    2004-01-01

    Mature dairy cattle were sampled over a 2-year period (2001-2002) on six farms in New Mexico and Texas. Fecal samples (n = 1560) were collected via rectal palpation and cultured for Salmonella, and one isolate from each positive sample was serotyped. Three isolates of each serotype, with the exception of Salmonella Newport (n = 12), were examined for susceptibility to 17 antimicrobial agents. Twenty-two different serotypes were identified from a total of 393 Salmonella isolates. Montevideo was the predominant serotype (27%) followed by Mbandaka (15%), Senftenberg (11.4%), Newport (6.4%), Anatum (4.8%), and Give (4.8%). Salmonella Typhimurium and Dublin, two frequently reported serotypes, accounted for only 1% of the observed serotypes in this study. Sixty-four percent of the serotypes were susceptible to all 17 antimicrobials, 14% were resistant to a single agent, and 22% were multiresistant (2-11 types of resistance). All isolates tested were susceptible to amikacin, apramycin, imipenem, ceftriaxone, nalidixic acid, and ciprofloxacin. The most frequent types of resistance were to sulfamethoxazole, tetracycline, streptomycin, kanamycin, chloramphenicol, and ampicillin (ranging from 8.9 to 22.4%). Serotypes demonstrating multiple resistance included Dublin and Give (resistant to three or more antibiotics), Typhimurium (resistant to five antibiotics), and Newport (four and two isolates resistant to six and nine antibiotics, respectively). Class 1 integrons were present in only two Salmonella Dublin isolates and one Salmonella Newport isolate. The most prevalent resistance patterns observed in this study were toward antimicrobial agents commonly used in cattle, while all Salmonella isolates were susceptible to ceftriaxone and ciprofloxacin, antibiotics used in human medicine.

  6. Genetic characteristics and antimicrobial resistance of Escherichia coli from Japanese macaques (Macaca fuscata) in rural Japan.

    PubMed

    Ogawa, Keiko; Yamaguchi, Keiji; Suzuki, Masatsugu; Tsubota, Toshio; Ohya, Kenji; Fukushi, Hideto

    2011-04-01

    Escherichia coli was isolated from wild and captive Japanese macaques (Macaca fuscata) to investigate the risk of zoonotic infections and the prevalence of antimicrobial-resistant Escherichia coli in the wild macaque population in Shimokita Peninsula, a rural area of Japan. We collected 265 fresh fecal samples from wild macaques and 20 samples from captive macaques in 2005 and 2006 for E. coli isolation. The predominant isolates were characterized by serotyping, virulence gene profiling, plasmid profiling, pulsed-field gel electrophoresis (PFGE), and microbial sensitivity tests. In total, 248 E. coli strains were isolated from 159 fecal samples from wild macaques, and 42 E. coli were isolated from 17 samples from captive macaques. None of the virulence genes eae, stx, elt, and est were detected in any of the isolates. The relatedness between wild- and captive-derived isolates was low by serotyping, PFGE, and plasmid profiling. Serotypes O8:H6, O8:H34, O8:H42, O8:HUT, O103:H27, O103:HNM, and OUT:H27 were found in wild macaque feces; serotypes O157:H42 and O119:H21 were recovered from captive macaques. O-and H-serotypes of the 26 isolates were not typed by commercial typing antisera and were named OUT and HUT, respectively. Twenty-eight isolates had no flagellar antigen, and their H-serotypes were named HNM. Similarity of PFGE patterns between wild-derived isolates and captive-derived isolates was <70%. No plasmid profile was shared between wild-derived and captive-derived isolates. The prevalence of antimicrobial-resistant E. coli was 6.5% (n=62) in wild macaques, and these isolates were resistant to cephalothin. We conclude that wild Japanese macaques in Shimokita Peninsula were unlikely to act as a reservoir of pathogenic E. coli for humans and that antimicrobial-resistant E. coli in wild macaques may be derived from humans.

  7. [Antimicrobial susceptibility patterns of Gram-negative bacteria isolated in urinary tract infections in Venezuela: Results of the SMART study 2009-2012].

    PubMed

    Guevara, Napoleón; Guzmán, Manuel; Merentes, Altagracia; Rizzi, Adele; Papaptzikos, Juana; Rivero, Narlesky; Oranges, Carmela; Vlllarroel, Héctor; Limas, Yoxsivell

    2015-12-01

    Antimicrobial resistance of pathogens causing urinary tract infection (UTI) is a growing problem, which complicates their effective treatment. Surveillance is needed to guide appropriate empiric therapy. to describe the susceptibility patterns of Gram-negative bacteria isolated of patients with UTI to twelve antibiotics as part of the Study for Monitoring Antimicrobial Resistance Trends in Venezuela. Between 2009-2012 a total of 472 Gram-negative bacteria were isolated from hospitalized patients with UTI. The isolates were sent to Central Laboratory (Central Laboratory of International Health Management Associates) to confirm their identification, and to make susceptibility testing as recommended by the Clinical and Laboratory Standards Institute. Enterobacteriacea comprised 96.6% of the total, where Escherichia coli (76.9%) and Klebsiella pneumoniae (10.6%) were the most frequent. Extended-spectrum β-lactamases (ESBL) was detected in 21.6% of isolates. Top antimicrobial activity were ertapenem, imipenem, and amikacin (> 90.0%), slightly lower for amikacin (85.1%) in ESBL-producing strains. Resistance rates to fluoroquinolones and ampicillin/sulbactam were high (40 y 64%, respectively). These data suggest a necessary revision of the therapeutic regimens for the empirical treatment of UTI in Venezuela.

  8. Methodological comparisons for antimicrobial resistance surveillance in feedlot cattle

    PubMed Central

    2013-01-01

    Background The purpose of this study was to objectively compare methodological approaches that might be utilized in designing an antimicrobial resistance (AMR) surveillance program in beef feedlot cattle. Specifically, four separate comparisons were made to investigate their potential impact on estimates for prevalence of AMR. These included investigating potential differences between 2 different susceptibility testing methods (broth microdilution and disc diffusion), between 2 different target bacteria (non-type-specific E. coli [NTSEC] and Mannheimia haemolytica), between 2 strategies for sampling feces (individual samples collected per rectum and pooled samples collected from the pen floor), and between 2 strategies for determining which cattle to sample (cattle that were culture-positive for Mannheimia haemolytica and those that were culture-negative). Results Comparing two susceptibility testing methods demonstrated differences in the likelihood of detecting resistance between automated disk diffusion (BioMIC®) and broth microdilution (Sensititre®) for both E. coli and M. haemolytica. Differences were also detected when comparing resistance between two bacterial organisms within the same cattle; there was a higher likelihood of detecting resistance in E. coli than in M. haemolytica. Differences in resistance prevalence were not detected when using individual animal or composite pen sampling strategies. No differences in resistance prevalences were detected in E. coli recovered from cattle that were culture-positive for M. haemolytica compared to those that were culture-negative, suggesting that sampling strategies which targeted recovery of E. coli from M. haemolytica-positive cattle would not provide biased results. Conclusions We found that for general purposes, the susceptibility test selected for AMR surveillance must be carefully chosen considering the purpose of the surveillance since the ability to detect resistance appears to vary between these tests

  9. Isolation and analysis of bacteria with antimicrobial activities from the marine sponge Haliclona simulans collected from Irish waters.

    PubMed

    Kennedy, Jonathan; Baker, Paul; Piper, Clare; Cotter, Paul D; Walsh, Marcella; Mooij, Marlies J; Bourke, Marie B; Rea, Mary C; O'Connor, Paula M; Ross, R Paul; Hill, Colin; O'Gara, Fergal; Marchesi, Julian R; Dobson, Alan D W

    2009-01-01

    Samples of the marine sponge Haliclona simulans were collected from Irish coastal waters, and bacteria were isolated from these samples. Phylogenetic analyses of the cultured isolates showed that four different bacterial phyla were represented; Bacteriodetes, Actinobacteria, Proteobacteria, and Firmicutes. The sponge bacterial isolates were assayed for the production of antimicrobial substances, and biological activities against Gram-positive and Gram-negative bacteria and fungi were demonstrated, with 50% of isolates showing antimicrobial activity against at least one of the test strains. Further testing showed that the antimicrobial activities extended to the important pathogens Pseudomonas aeruginosa, Clostridium difficile, multi-drug-resistant Staphylococcus aureus, and pathogenic yeast strains. The Actinomycetes were numerically the most abundant producers of antimicrobial activities, although activities were also noted from Bacilli and Pseudovibrio isolates. Surveys for the presence of potential antibiotic encoding polyketide synthase and nonribosomal peptide synthetase genes also revealed that genes for the biosynthesis of these secondary metabolites were present in most bacterial phyla but were particularly prevalent among the Actinobacteria and Proteobacteria. This study demonstrates that the culturable fraction of bacteria from the sponge H. simulans is diverse and appears to possess much potential as a source for the discovery of new medically relevant biological active agents.

  10. Isolation and Identification of Phyllospheric Bacteria Possessing Antimicrobial Activity from Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium and Hippocrepis unisiliqousa.

    PubMed

    Mazinani, Zohreh; Zamani, Marzieh; Sardari, Soroush

    2017-01-01

    The widespread utilization of antimicrobial compounds has caused emergence of resistant microorganisms in the world. Hence, the research to probe the products with antimicrobial features has led to finding natural habitats and discovering new pharmaceutical products. In this study, an attempt was made to explore the niche of novel habitat to isolate pyllospheric bacteria from the above ground parts (stems and leaves) of Astragalus obtusifolius , Prosopis juliflora , Xanthium strumarium , and Hippocrepis unisiliqousa to evaluate their antimicrobial features. The inhibitory effects of these strains on the growth of two fungi ( Aspergillus niger , Aspergillus fumigatus ), two yeasts ( Saccharomyces cerevisiae , Candida albicans ) and six bacteria ( Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Bacillus subtilis , Salmonella typhi , Streptococcus pyogenes ) were tested. In total, 113 bacterial strains were isolated. Twenty five bacterial strains (B-1 to B-25) indicated promising antimicrobial (antibacterial and antifungal) activities against aforementioned pathogens. The identification of the bacterial strains was ascertained by morphological, physiological, biochemical tests and two strains with the strongest antimicrobial activities were further characterized based on 16s rRNA sequencing. These two strains were identified as Bacillus amyloliquefaciens . Our results provide evidence that phyllospheric microorganisms are capable of producing some compounds with antimicrobial properties.

  11. Effect of manure application rate and timing on the leaching potential of antibiotic resistant bacteria.

    USDA-ARS?s Scientific Manuscript database

    Antibiotics are used in swine production for therapeutic and growth promotion purposes. Because land application is the most common method of disposing of swine lagoon effluent, there exists the potential threat of contaminating the underlying groundwater with antimicrobial-resistant bacteria (ARB) ...

  12. Antimicrobial resistance issues in beef production

    USDA-ARS?s Scientific Manuscript database

    Antimicrobial resistance threats to human health as identified have been recognized as a critical global public health concern. Linkage of some threats to beef production is discussed. The relevance to beef production of recent government actions will be examined. Prominent antimicrobial resistance ...

  13. Inhibition of the virulence, antibiotic resistance, and fecal shedding of multiple antibiotic-resistant Salmonella Typhimurium in broilers fed Original XPC™

    PubMed Central

    Feye, K. M.; Anderson, K. L.; Scott, M. F.; McIntyre, D. R.; Carlson, S. A.

    2016-01-01

    Salmonella carriage is an insidious problem for the poultry industry. While most Salmonella serotypes are avirulent in poultry, these bacteria can contaminate chicken meat during processing, leading to one of the most important food safety hazards. In this study, we examined the anti-Salmonella effects of Diamond V Original XPC™ (XPC) included in the finisher diet fed to commercial broilers. On 3 occasions between day one (D1) and D20, broilers were experimentally infected with multiple antibiotic-resistant Salmonella Typhimurium. After confirming that the chicks were shedding Salmonella in the feces on D21, broiler chicks were fed a diet containing XPC (n = 57 birds; 1.25 kg/MT) or an XPC-free control diet (CON) (n = 57 birds) to D49. Fecal samples were obtained weekly and subjected to selective culture for enumerating and determining the antibiotic resistance of the Salmonella. Salmonella isolates were then subjected to an in vitro virulence assay, which predicts the ability of Salmonella to cause illness in a mammalian host. Broilers were euthanized on D49 and a segment of the large intestine was removed and subjected to the same assays used for the fecal samples. When compared to the birds fed the CON diet, Salmonella fecal shedding, virulence (invasion and invasion gene expression), and antibiotic resistance were significantly decreased in birds fed XPC (5-fold, 7.5-fold, 6-fold, and 5.3-fold decreases, respectively). Birds fed XPC exhibited heavier body weight (BW) and greater BW gains than those fed the CON diet. The decrease in virulence was associated with a decreased expression of a genetic regulator of Salmonella invasion into cells (hilA), while the decrease in antibiotic resistance was due to a loss of an integron (SGI1) from the input strain. This study revealed that Original XPC™ inhibits the shedding, downstream virulence, and antibiotic resistance of Salmonella residing in broilers. PMID:27566726

  14. A proposed analytic framework for determining the impact of an antimicrobial resistance intervention.

    PubMed

    Grohn, Yrjo T; Carson, Carolee; Lanzas, Cristina; Pullum, Laura; Stanhope, Michael; Volkova, Victoriya

    2017-06-01

    Antimicrobial use (AMU) is increasingly threatened by antimicrobial resistance (AMR). The FDA is implementing risk mitigation measures promoting prudent AMU in food animals. Their evaluation is crucial: the AMU/AMR relationship is complex; a suitable framework to analyze interventions is unavailable. Systems science analysis, depicting variables and their associations, would help integrate mathematics/epidemiology to evaluate the relationship. This would identify informative data and models to evaluate interventions. This National Institute for Mathematical and Biological Synthesis AMR Working Group's report proposes a system framework to address the methodological gap linking livestock AMU and AMR in foodborne bacteria. It could evaluate how AMU (and interventions) impact AMR. We will evaluate pharmacokinetic/dynamic modeling techniques for projecting AMR selection pressure on enteric bacteria. We study two methods to model phenotypic AMR changes in bacteria in the food supply and evolutionary genotypic analyses determining molecular changes in phenotypic AMR. Systems science analysis integrates the methods, showing how resistance in the food supply is explained by AMU and concurrent factors influencing the whole system. This process is updated with data and techniques to improve prediction and inform improvements for AMU/AMR surveillance. Our proposed framework reflects both the AMR system's complexity, and desire for simple, reliable conclusions.

  15. Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria.

    PubMed

    Valle, Demetrio L; Puzon, Juliana Janet M; Cabrera, Esperanza C; Rivera, Windell L

    2016-01-01

    This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with R f values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with R f values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an R f value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs.

  16. Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria

    PubMed Central

    Valle, Demetrio L.; Puzon, Juliana Janet M.; Cabrera, Esperanza C.

    2016-01-01

    This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with R f values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with R f values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an R f value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs. PMID:27478476

  17. Comparison and continuous estimates of fecal coliform and Escherichia coli bacteria in selected Kansas streams, May 1999 through April 2002

    USGS Publications Warehouse

    Rasmussen, Patrick P.; Ziegler, Andrew C.

    2003-01-01

    The sanitary quality of water and its use as a public-water supply and for recreational activities, such as swimming, wading, boating, and fishing, can be evaluated on the basis of fecal coliform and Escherichia coli (E. coli) bacteria densities. This report describes the overall sanitary quality of surface water in selected Kansas streams, the relation between fecal coliform and E. coli, the relation between turbidity and bacteria densities, and how continuous bacteria estimates can be used to evaluate the water-quality conditions in selected Kansas streams. Samples for fecal coliform and E. coli were collected at 28 surface-water sites in Kansas. Of the 318 samples collected, 18 percent exceeded the current Kansas Department of Health and Environment (KDHE) secondary contact recreational, single-sample criterion for fecal coliform (2,000 colonies per 100 milliliters of water). Of the 219 samples collected during the recreation months (April 1 through October 31), 21 percent exceeded the current (2003) KDHE single-sample fecal coliform criterion for secondary contact rec-reation (2,000 colonies per 100 milliliters of water) and 36 percent exceeded the U.S. Environmental Protection Agency (USEPA) recommended single-sample primary contact recreational criterion for E. coli (576 colonies per 100 milliliters of water). Comparisons of fecal coliform and E. coli criteria indicated that more than one-half of the streams sampled could exceed USEPA recommended E. coli criteria more frequently than the current KDHE fecal coliform criteria. In addition, the ratios of E. coli to fecal coliform (EC/FC) were smallest for sites with slightly saline water (specific conductance greater than 1,000 microsiemens per centimeter at 25 degrees Celsius), indicating that E. coli may not be a good indicator of sanitary quality for those streams. Enterococci bacteria may provide a more accurate assessment of the potential for swimming-related illnesses in these streams. Ratios of EC/FC and

  18. Serratia marcescens resistance profile and its susceptibility to photodynamic antimicrobial chemotherapy.

    PubMed

    Parente, Ticiana Mont Alverne Lopes; Rebouças, Emanuela de Lima; Santos, Vitor Coutinho Vieira Dos; Barbosa, Francisco Cesar Barroso; Zanin, Iriana Carla Junqueira

    2016-06-01

    Some authors have reported the antimicrobial action of photodynamic antimicrobial chemotherapy (PACT) on bacteria related to nosocomial infections but there are few studies evaluating PACT on Serratia marcescens grown as planktonic cultures or as biofilms. The purpose of this study was to analyze the S. marcescens resistance profile and its susceptibility to PACT. Initially, 55 S. marcescens strains isolated from environmental, oral and extra-oral infections were tested by antimicrobial resistance to cefotaxime (CTX), imipenem (IPM), ciprofloxacin (CIP), tobramycin (TOB) and doxycycline (DOX) using E-test(®). Following, isolates grown as planktonic cultures or biofilms were submitted to PACT using the association of a light-emitting diode and toluidine blue (TBO). The E-test(®) results demonstrated intermediated sensitive strains to CTX, IMP, TOB, and DOX; and resistant strains to CTX, TOB, DOX and CIP. Also, CTX and IMP demonstrated variation when CLSI 2007 and CLSI 2015 were compared. Planktonic cultures and biofilms submitted to PACT demonstrated counts varying from 10(11) to 10(7) for planktonic cultures and 10(10) to 10(7) for biofilms. There were no statistical differences in the results when planktonic cultures and biofilms were compared. Increase in the profile of S. marcescens resistance was observed when CLSI 2007 and CLSI 2015 were compared. Also, IMP remains as the drug with lower rate of resistance. Additionally, both S. marcescens planktonic cultures and early biofilms are susceptible to PACT under tested conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. The prevalence of antimicrobial-resistant Escherichia coli in two species of invasive alien mammals in Japan.

    PubMed

    Nakamura, Ichiro; Obi, Takeshi; Sakemi, Yoko; Nakayama, Ayano; Miyazaki, Kei; Ogura, Go; Tamaki, Masanobu; Oka, Tatsuzo; Takase, Kozo; Miyamoto, Atsushi; Kawamoto, Yasuhiro

    2011-08-01

    The prevalence of antimicrobial resistance in 128 Escherichia coli isolates was investigated in two species of invasive alien mammals (IAMs): the small Asian mongoose (SAM) and Japanese weasel (JW). The SAM is found on the main island of Okinawa, Japan, where a large number of livestock is available, and the JW is present on a small island, where is isolated from the main island, and have a small number of livestock. We focused on the two IAMs, inhabiting under the different environments, and compared their prevalence of antimicrobial-resistant E. coli. In the comparison of the frequencies of antimicrobial-resistant E. coli isolates between the SAM and JW, JW showed significantly higher prevalence of resistance against three drugs, ampicillin, chlortetracycline and nalidixic acid, compared with SAM's test results (P<0.05). The bla(TEM) gene and the aph1 gene were detected in 35 subjects (91%) of ampicillin-resistant isolates and 6 subjects (100%) of kanamycin-resistant isolates, respectively. The tet (A) gene was detected in 62 subjects (46%) of CTC-resistant isolates, and the tet (B) gene was detected in 25 subjects (8%) of those in IAM. The present results suggest that some IAMs were the carrier of antimicrobial-resistant bacteria and their genes, and the frequencies of these resistances were different between two IAM species.

  20. Influence of manure age and sunlight on the community structure of cattle fecal bacteria as revealed by Illumina sequencing

    NASA Astrophysics Data System (ADS)

    Wong, K.; Shaw, T. I.; Oladeinde, A.; Molina, M.

    2013-12-01

    Fecal pollution of environmental waters is a major concern for the general public because exposure to fecal-associated pathogens can have severe impacts on human health. Stream and river impairment due to fecal pollution is largely the result of agricultural activities in the United States. In the last few years, numerous metagenomic studies utilized next generation sequencing to develop microbial community profiles by massively sequencing the 16sRNA hypervariable region. This technology supports the application of water quality assessment such as pathogen detection and fecal source tracking. The bacteria communities of samples in these studies were determined when they were freshly collected; therefore, little is known about how feces age or how environmental stress influences the microbial ecology of fecal materials. In this study we monitored bacteria community changes in cattle feces for 57 days after excretion (day 0, 2, 4 8, 15, 22, 29, 43, 57) by sequencing the 16s variable region 4, using Illumnia MiSeq. Twelve cattle feces were studied; half of the samples were directly exposed to sunlight (unshaded) and half were shaded. Results indicate that the relative abundance (RA) profile in both shaded and unshaded samples rapidly changed from day 0 to 15, but stabilized from day 22 to 57. Firmcutes were the most abundant phylum (~40%) at day 0, but were reduced to <10% by day 57. The RA of Proteobacteria was only 1% at day 0, but increased to ~50% by day 57in both shaded and unshaded samples. By the end of the study, shaded and unshaded samples had a similar RA of Firmcutes and Proteobacteria but the RA of Bacteroidetes and Actinobacteria was, respectively, about 7% lower and 10% higher for unshaded samples. UV intensity, moisture, and temperature were significantly different between shaded and unshaded plots, indicating that these environmental stresses could influence the structure of fecal bacteria community in the natural environment. According to the

  1. Antimicrobial Resistance Profiles of Listeria monocytogenes and Listeria innocua Isolated from Ready-to-Eat Products of Animal Origin in Spain.

    PubMed

    Escolar, Cristina; Gómez, Diego; Del Carmen Rota García, María; Conchello, Pilar; Herrera, Antonio

    2017-06-01

    The objective of this work was to investigate the antimicrobial resistance in Listeria spp. isolated from food of animal origin. A total of 50 Listeria strains isolated from meat and dairy products, consisting of 7 Listeria monocytogenes and 43 Listeria innocua strains, were characterized for antimicrobial susceptibility against nine antimicrobials. The strains were screened by real-time PCR for the presence of antimicrobial resistance genes: tet M, tet L, mef A, msr A, erm A, erm B, lnu A, and lnu B. Multidrug resistance was identified in 27 Listeria strains, 4 belonging to L. monocytogenes. Resistance to clindamycin was the most common resistance phenotype and was identified in 45 Listeria strains; the mechanisms of resistance are still unknown. A medium prevalence of resistance to tetracycline (15 and 9 resistant and intermediate strains) and ciprofloxacin (13 resistant strains) was also found. Tet M was detected in Listeria strains with reduced susceptibility to tetracycline, providing evidence that both L. innocua and L. monocytogenes displayed acquired resistance. The presence of antimicrobial resistance genes in L. innocua and L. monocytogenes indicates that these genes may be transferred to commensal and pathogenic bacteria via the food chain; besides this, antibiotic resistance in L. monocytogenes could compromise the effective treatment of listeriosis in humans.

  2. Molecular epidemiology and antimicrobial resistance of Salmonella Typhimurium DT104 on Ontario swine farms

    PubMed Central

    Farzan, Abdolvahab; Friendship, Robert M.; Poppe, Cornelis; Martin, Laura; Dewey, Catherine E.; Funk, Julie

    2008-01-01

    This study was conducted to examine antimicrobial resistances, plasmid profiles, and pulsed-field gel electrophoresis patterns of 80 Salmonella Typhimurium (including var. Copenhagen) DT104 strains (including DT104a and DT104b) recovered from pig and environmental fecal samples on 17 swine farms in Ontario. No resistance was observed to amoxicillin/clavulanic acid, apramycin, carbadox, cephalothin, ceftriaxone, ceftiofur, cefoxitin, ciprofloxacin, nalidixic acid, trimethoprim, and tobramycin. However, the isolates exhibited resistance against 4 to 10 antimicrobials with the most frequent resistance being to sulfonamides (Su), ampicillin (A), streptomycin (S), spectinomycin (Sp), chloramphenicol (C), tetracycline (T), and florfenicol (F). Thirteen distinct resistance patterns were determined but 88% of isolates shared the typical resistance pattern “ACSpSSuT.” Twelve different plasmid profiles were observed; the 62 MDa virulence-associated plasmid was detected in 95% of the isolates. The 2.1 MDa plasmid was the second most frequent one, which was harbored by 65% isolates. The isolates were classified into 23 distinct genotypes by PFGE-SpeI + BlnI when difference in at least one fragment was defined as a distinct genotype. In total, 39 distinct “types” were observed when defining a “type” based on the combination of antimicrobial resistance, plasmid pattern, and PFGE-SpeI + BlnI for each isolate. The highest diversity was 0.96 (95% CI: 0.92, 0.96) for the “type” described above followed by 0.92 (95% CI: 0.88, 0.93) for PFGE-SpeI + BlnI. The diversity of DT104 isolates indicates there might be multiple sources for this microorganism on swine farms. This knowledge might be used to track these sources, as well as to study the extent of human salmonellosis attributed to pork compared to food products derived from other food-producing animals. PMID:18505209

  3. Pharmacokinetic-Pharmacodynamic Model To Evaluate Intramuscular Tetracycline Treatment Protocols To Prevent Antimicrobial Resistance in Pigs

    PubMed Central

    Ahmad, Amais; Græsbøll, Kaare; Christiansen, Lasse Engbo; Toft, Nils; Matthews, Louise

    2014-01-01

    High instances of antimicrobial resistance are linked to both routine and excessive antimicrobial use, but excessive or inappropriate use represents an unnecessary risk. The competitive growth advantages of resistant bacteria may be amplified by the strain dynamics; in particular, the extent to which resistant strains outcompete susceptible strains under antimicrobial pressure may depend not only on the antimicrobial treatment strategies but also on the epidemiological parameters, such as the composition of the bacterial strains in a pig. This study evaluated how variation in the dosing protocol for intramuscular administration of tetracycline and the composition of bacterial strains in a pig affect the level of resistance in the intestine of a pig. Predictions were generated by a mathematical model of competitive growth of Escherichia coli strains in pigs under specified plasma concentration profiles of tetracycline. All dosing regimens result in a clear growth advantage for resistant strains. Short treatment duration was found to be preferable, since it allowed less time for resistant strains to outcompete the susceptible ones. Dosing frequency appeared to be ineffective at reducing the resistance levels. The number of competing strains had no apparent effect on the resistance level during treatment, but possession of fewer strains reduced the time to reach equilibrium after the end of treatment. To sum up, epidemiological parameters may have more profound influence on growth dynamics than dosing regimens and should be considered when designing improved treatment protocols. PMID:25547361

  4. Isolation, Antimicrobial Susceptibility Profile and Detection of Sul1, blaTEM, and blaSHV in Amoxicillin-Clavulanate-Resistant Bacteria Isolated From Retail Sausages in Kampar, Malaysia

    PubMed Central

    Tew, Lih-Shin; She, Li-Yen; Chew, Choy-Hoong

    2016-01-01

    Background Due to the overuse of antibiotics in livestock as a growth-promoting agent, the emergence of multi-antibiotic resistant bacteria is becoming a concern. Objectives In this study, we aimed to detect the presence and discover the molecular determinants of foodborne bacteria in retail sausages resistant towards the antibacterial agent amoxicillin-clavulanate. Methods Two grams of sausages were chopped into small pieces and transferred into sterile Luria-Bertani (LB) enrichment broths overnight before they were plated on MacConkey agar petri dishes. The bacteria isolated were then screened for amoxicillin-clavulanate resistance, and an antimicrobial susceptibility test of each isolate was performed by using the disc diffusion method. Double synergy and phenotypic tests were carried out to detect the presence of extended spectrum β-lactamase (ESBL). API 20E kit was used to identify the Enterobacteriaceae. All isolates were further examined by polymerase chain reaction (PCR) for resistant genes blaOXA-1, blaOXA-10, plasmid-mediated AmpC (blaCMY and blaDHA), and the chromosome-mediated AmpC, Sul1, blaTEM, and blaSHV genes. Results A total of 18 amoxicillin-clavulanate resistant isolates were obtained from seven different types of retail sausages. Only half of them were identified as Enterobacteriaceae, but none were ESBL-producers. All the 18 isolated strains demonstrated resistance towards amoxicillin-clavulanate, penicillin and oxacillin (100%), cefotaxime (71.4%), cefpodoxime (66.7%), and ampicillin (83.3%). blaTEM was the most frequently detected β-lactamase gene. Both plasmid- and chromosomal-bound blaTEM genes were detected in all of the isolated Enterobacteriaceae. blaSHV and Sul1 accounted for 22.2% and 11.1% of the amoxicillin-clavulanate resistant isolates, respectively, whereas blaAMPC, blaCMY, blaDHA, blaOXA-1, and blaOXA-10 were not found in any of the isolates. The only one ESBL-producing bacteria detected in this study was Chryseobacterium

  5. Isolation, Antimicrobial Susceptibility Profile and Detection of Sul1, blaTEM, and blaSHV in Amoxicillin-Clavulanate-Resistant Bacteria Isolated From Retail Sausages in Kampar, Malaysia.

    PubMed

    Tew, Lih-Shin; She, Li-Yen; Chew, Choy-Hoong

    2016-10-01

    Due to the overuse of antibiotics in livestock as a growth-promoting agent, the emergence of multi-antibiotic resistant bacteria is becoming a concern. In this study, we aimed to detect the presence and discover the molecular determinants of foodborne bacteria in retail sausages resistant towards the antibacterial agent amoxicillin-clavulanate. Two grams of sausages were chopped into small pieces and transferred into sterile Luria-Bertani (LB) enrichment broths overnight before they were plated on MacConkey agar petri dishes. The bacteria isolated were then screened for amoxicillin-clavulanate resistance, and an antimicrobial susceptibility test of each isolate was performed by using the disc diffusion method. Double synergy and phenotypic tests were carried out to detect the presence of extended spectrum β-lactamase (ESBL). API 20E kit was used to identify the Enterobacteriaceae . All isolates were further examined by polymerase chain reaction (PCR) for resistant genes bla OXA-1, bla OXA-10, plasmid-mediated AmpC ( bla CMY and bla DHA), and the chromosome-mediated AmpC, Sul 1, bla TEM, and bla SHV genes. A total of 18 amoxicillin-clavulanate resistant isolates were obtained from seven different types of retail sausages. Only half of them were identified as Enterobacteriaceae , but none were ESBL-producers. All the 18 isolated strains demonstrated resistance towards amoxicillin-clavulanate, penicillin and oxacillin (100%), cefotaxime (71.4%), cefpodoxime (66.7%), and ampicillin (83.3%). bla TEM was the most frequently detected β-lactamase gene. Both plasmid- and chromosomal-bound bla TEM genes were detected in all of the isolated Enterobacteriaceae . bla SHV and Sul 1 accounted for 22.2% and 11.1% of the amoxicillin-clavulanate resistant isolates, respectively, whereas bla AMPC, bla CMY, bla DHA, bla OXA-1, and bla OXA-10 were not found in any of the isolates. The only one ESBL-producing bacteria detected in this study was Chryseobacterium meningosepticum , which

  6. Fecal-indicator bacteria in the Newfound Creek watershed, western North Carolina, during a high and low streamflow condition, 2003

    USGS Publications Warehouse

    Giddings, Elise M.; Oblinger, Carolyn J.

    2004-01-01

    Water quality in the Newfound Creek watershed has been shown to be affected by bacteria, sediment, and nutrients. In this study, Escherichia coli (E. coli) bacteria were sampled at five sites in Newfound Creek and five tributary sites during low flow on May 28, 2003, and high flow on November 19, 2003. In addition, a subset of five sites was sampled for fecal coliform bacteria, E. coli bacteria in streambed sediments (low flow only), and coliphage virus for serotyping. Coliphage virus serotyping has been used to identify human and animal sources of bacterial contamination. A streamflow gage was installed and operated to support ongoing water-quality studies in the watershed. Fecal coliform densities ranged from 92 to 27,000 colony-forming units per 100 milliliters of water for E. coli and 140 to an estimated 29,000 colony-forming units per 100 milliliters of water for fecal coliform during the two sampling visits. Ninety percent of the E. coli and fecal coliform samples exceeded corresponding U.S. Environmental Protection Agency or North Carolina water-quality criteria for recreational and ambient waters. During low flow, the middle part of the Newfound Creek watershed and the Dix Creek tributary had the highest densities of E. coli bacteria. During the high-flow sampling, all tributaries contained high densities of E. coli bacteria, although Dix Creek and Round Hill Branch were the largest contributors of these bacteria to Newfound Creek. Coliphage virus serotyping results were inconclusive because most samples did not contain the male-specific RNA coliphage needed for serotyping. Positive results indicated, however, that during low flow, non-human sources of bacteria were present in Sluder Branch, and during high flow, human sources of bacteria were present in Round Hill Branch. Sampling of bacteria in streambed sediments during low flow indicated that sediments do not appear to be a substantial source of bacteria relative to the water column, with the exception

  7. Efficacy of antimicrobial 405 nm blue-light for inactivation of airborne bacteria

    NASA Astrophysics Data System (ADS)

    Dougall, Laura R.; Anderson, John G.; Timoshkin, Igor V.; MacGregor, Scott J.; Maclean, Michelle

    2018-02-01

    Airborne transmission of infectious organisms is a considerable concern within the healthcare environment. A number of novel methods for `whole room' decontamination, including antimicrobial 405 nm blue light, are being developed. To date, research has focused on its effects against surface-deposited contamination; however, it is important to also establish its efficacy against airborne bacteria. This study demonstrates evidence of the dose-response kinetics of airborne bacterial contamination when exposed to 405 nm light and compares bacterial susceptibility when exposed in three different media: air, liquid and surfaces. Bacterial aerosols of Staphylococcus epidermidis, generated using a 6-Jet Collison nebulizer, were introduced into an aerosol suspension chamber. Aerosolized bacteria were exposed to increasing doses of 405 nm light, and air samples were extracted from the chamber using a BioSampler liquid impinger, with viability analysed using pour-plate culture. Results have demonstrated successful aerosol inactivation, with a 99.1% reduction achieved with a 30 minute exposure to high irradiance (22 mWcm-2) 405 nm light (P=0.001). Comparison to liquid and surface exposures proved bacteria to be 3-4 times more susceptible to 405 nm light inactivation when in aerosol form. Overall, results have provided fundamental evidence of the susceptibility of bacterial aerosols to antimicrobial 405 nm light treatment, which offers benefits in terms of increased safety for human exposure, and eradication of microbes regardless of antibiotic resistance. Such benefits provide advantages for a number of applications including `whole room' environmental decontamination, in which reducing levels of airborne bacteria should reduce the number of infections arising from airborne contamination.

  8. In vitro antimicrobial activity of five essential oils on multidrug resistant Gram-negative clinical isolates

    PubMed Central

    Sakkas, Hercules; Gousia, Panagiota; Economou, Vangelis; Sakkas, Vassilios; Petsios, Stefanos; Papadopoulou, Chrissanthy

    2016-01-01

    Aim/Background: The emergence of drug-resistant pathogens has drawn attention on medicinal plants for potential antimicrobial properties. The objective of the present study was the investigation of the antimicrobial activity of five plant essential oils on multidrug resistant Gram-negative bacteria. Materials and Methods: Basil, chamomile blue, origanum, thyme, and tea tree oil were tested against clinical isolates of Acinetobacter baumannii (n = 6), Escherichia coli (n = 4), Klebsiella pneumoniae (n = 7), and Pseudomonas aeruginosa (n = 5) using the broth macrodilution method. Results: The tested essential oils produced variable antibacterial effect, while Chamomile blue oil demonstrated no antibacterial activity. Origanum, Thyme, and Basil oils were ineffective on P. aeruginosa isolates. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values ranged from 0.12% to 1.50% (v/v) for tea tree oil, 0.25-4% (v/v) for origanum and thyme oil, 0.50% to >4% for basil oil and >4% for chamomile blue oil. Compared to literature data on reference strains, the reported MIC values were different by 2SD, denoting less successful antimicrobial activity against multidrug resistant isolates. Conclusions: The antimicrobial activities of the essential oils are influenced by the strain origin (wild, reference, drug sensitive, or resistant) and it should be taken into consideration whenever investigating the plants’ potential for developing new antimicrobials. PMID:27366345

  9. Influence of housing systems on microbial load and antimicrobial resistance patterns of Escherichia coli isolates from eggs produced for human consumption.

    PubMed

    Alvarez-Fernández, Elena; Domínguez-Rodríguez, Jessica; Capita, Rosa; Alonso-Calleja, Carlos

    2012-05-01

    Microbial counts (aerobic bacteria, psychrotrophs, Enterobacteriaceae, coliforms, Pseudomonas spp., Enterococcus spp., Staphylococcus spp., and molds and yeasts) were obtained for the shells of 240 table eggs in northwestern Spain. Eggs from six sources (40 samples in each) were analyzed: chicken eggs from five different housing systems (conventional battery cages, barn, free range, organic, and domestic breeding) and quail eggs (cages). A total of 120 Escherichia coli strains (20 from each source) were tested by the disk diffusion method for resistance to 12 antimicrobial drugs of veterinary and human health significance. Aerobic plate counts ranged from 1.96 ± 1.0 (barn) to 3.69 ± 0.7 (domestic) log CFU/cm(2). Counts for most microbial groups differed significantly between sources. Eggs from domestic production had the highest contamination loads (P < 0.05) for aerobic bacteria, Enterococcus spp., and molds and yeasts and the highest prevalence of E. coli. Twenty-three E. coli isolates (19.17%) were susceptible to all antimicrobials tested, and 80.83 % were resistant to one (22.50%) or more (58.33%) antimicrobials. The housing system had a significant influence (P < 0.05) on the average resistance per strain, with the highest resistance in conventional cage (2.85) and barn (3.10) systems followed by free range (1.55) and quail (1.95). Eggs from organic (1.00) and domestic (0.75) production systems had the lowest resistance per strain. The highest prevalence of resistance was observed for the groups of antimicrobials more frequently used on poultry farms. Our results suggest that a relationship exists between the prevalence of antimicrobial resistance in E. coli strains and the more frequent use of antimicrobials in conventional (cage, barn, and free range) than in domestic and organic chicken housing systems. Education covering good sanitary practices for handling eggs to avoid cross-contamination or inadequate cooking is needed.

  10. Antimicrobial resistance in Escherichia coli O157 and non-O157 isolated from feces of domestic farm animals in Culiacan, Mexico

    USDA-ARS?s Scientific Manuscript database

    Antimicrobial resistance in E. coli O157 and non-O157 strains is a matter of increasing concern, and the association with some virulence traits in the same bacteria remains unclear. Inappropriate antimicrobial use in human and animal therapy has been associated with selective pressure in enteric mi...

  11. Decay of Fecal Indicator Bacteria and Microbial Source Tracking Markers in Cattle Feces

    EPA Science Inventory

    The survival of fecal indicator bacteria (FIB) and microbial source tracking (MST) markers in water microcosms and manure amended soils has been well documented; however, little is known about the survival of MST markers in bovine feces deposited on pastures. We conducted a study...

  12. Antimicrobial resistance and prudent drug use for Streptococcus suis.

    PubMed

    Varela, Norma P; Gadbois, Pierre; Thibault, Claude; Gottschalk, Marcelo; Dick, Paul; Wilson, Jeff

    2013-06-01

    This paper reviews information on antimicrobial resistance patterns and prudent use of antimicrobials to reduce the impact and spread of resistant Streptococcus suis strains. S. suis is an important pathogen in swine, which can cause significant economic loss. Prudent use of antimicrobials for S. suis is essential to preserve the therapeutic efficacy of broad-spectrum antimicrobials and to minimize selection of resistant S. suis strains. Resistance of S. suis to antimicrobials commonly used in swine, including lincosamides, macrolides, sulphonamides, and tetracycline, has been documented worldwide, with resistance in up to 85% of strains. Among antimicrobials examined, resistance of S. suis has been demonstrated to be relatively low for penicillin (0-27%), ampicillin (0.6-23%), and ceftiofur (0-23%). For penicillin, this result may be due in part to the unique mechanism by which resistance is acquired through modifications in the structure of penicillin-binding proteins. Recommendations to control S. suis infection include focused and careful choice and appropriate use of antimicrobials, together with preventive measures intended to improve swine management.

  13. Dental plaque bacteria with reduced susceptibility to chlorhexidine are multidrug resistant.

    PubMed

    Saleem, Hafiz Ghulam Murtaza; Seers, Christine Ann; Sabri, Anjum Nasim; Reynolds, Eric Charles

    2016-09-15

    Chlorhexidine (CHX) is used in oral care products to help control dental plaque. In this study dental plaque bacteria were grown on media containing 2 μg/ml chlorhexidine gluconate to screen for bacteria with reduced CHX susceptibility. The isolates were characterized by 16S rRNA gene sequencing and antibiotic resistance profiles were determined using the disc diffusion method. The isolates were variably resistant to multiple drugs including ampicillin, kanamycin, gentamicin and tetracycline. Two species, Chryseobacterium culicis and Chryseobacterium indologenes were able to grow planktonically and form biofilms in the presence of 32 μg/ml CHX. In the CHX and multidrug resistant C. indologenes we demonstrated a 19-fold up-regulation of expression of the HlyD-like periplasmic adaptor protein of a tripartite efflux pump upon exposure to 16 μg/ml CHX suggesting that multidrug resistance may be mediated by this system. Exposure of biofilms of these resistant species to undiluted commercial CHX mouthwash for intervals from 5 to 60 s indicated that the mouthwash was unlikely to eliminate them from dental plaque in vivo. The study highlights the requirement for increased vigilance of the presence of multidrug resistant bacteria in dental plaque and raises a potential risk of long-term use of oral care products containing antimicrobial agents for the control of dental plaque.

  14. Multivalent Antimicrobial Polymer Nanoparticles Target Mycobacteria and Gram-Negative Bacteria by Distinct Mechanisms

    PubMed Central

    2017-01-01

    Because of the emergence of antimicrobial resistance to traditional small-molecule drugs, cationic antimicrobial polymers are appealing targets. Mycobacterium tuberculosis is a particular problem, with multi- and total drug resistance spreading and more than a billion latent infections globally. This study reports nanoparticles bearing variable densities of poly(dimethylaminoethyl methacrylate) and the unexpected and distinct mechanisms of action this multivalent presentation imparts against Escherichia coli versus Mycobacterium smegmatis (model of M. tuberculosis), leading to killing or growth inhibition, respectively. A convergent “grafting to” synthetic strategy was used to assemble a 50-member nanoparticle library, and using a high-throughput screen identified that only the smallest (2 nm) particles were stable in both saline and complex cell media. Compared with the linear polymers, the nanoparticles displayed two- and eight-fold enhancements in antimicrobial activity against M. smegmatis and E. coli, respectively. Mechanistic studies demonstrated that the antimicrobial particles were bactericidal against E. coli due to rapid disruption of the cell membranes. Conversely, against M. smegmatis the particles did not lyse the cell membrane but rather had a bacteriostatic effect. These results demonstrate that to develop new polymeric antituberculars the widely assumed, broad spectrum, membrane-disrupting mechanism of polycations must be re-evaluated. It is clear that synthetic nanomaterials can engage in more complex interactions with mycobacteria, which we hypothesize is due to the unique cell envelope at the surface of these bacteria. PMID:29195272

  15. Isolation and Identification of Phyllospheric Bacteria Possessing Antimicrobial Activity from Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium and Hippocrepis unisiliqousa

    PubMed Central

    Mazinani, Zohreh; Zamani, Marzieh

    2017-01-01

    Background: The widespread utilization of antimicrobial compounds has caused emergence of resistant microorganisms in the world. Hence, the research to probe the products with antimicrobial features has led to finding natural habitats and discovering new pharmaceutical products. Methods: In this study, an attempt was made to explore the niche of novel habitat to isolate pyllospheric bacteria from the above ground parts (stems and leaves) of Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium, and Hippocrepis unisiliqousa to evaluate their antimicrobial features. The inhibitory effects of these strains on the growth of two fungi (Aspergillus niger, Aspergillus fumigatus), two yeasts (Saccharomyces cerevisiae, Candida albicans) and six bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella typhi, Streptococcus pyogenes) were tested. Results: In total, 113 bacterial strains were isolated. Twenty five bacterial strains (B-1 to B-25) indicated promising antimicrobial (antibacterial and antifungal) activities against aforementioned pathogens. The identification of the bacterial strains was ascertained by morphological, physiological, biochemical tests and two strains with the strongest antimicrobial activities were further characterized based on 16s rRNA sequencing. These two strains were identified as Bacillus amyloliquefaciens. Conclusion: Our results provide evidence that phyllospheric microorganisms are capable of producing some compounds with antimicrobial properties. PMID:28090278

  16. A Synoptic Study of Fecal-Indicator Bacteria in the Wind River, Bighorn River, and Goose Creek Basins, Wyoming, June-July 2000

    USGS Publications Warehouse

    Clark, Melanie L.; Gamper, Merry E.

    2003-01-01

    A synoptic study of fecal-indicator bacteria was conducted during June and July 2000 in the Wind River, Bighorn River, and Goose Creek Basins in Wyoming as part of the U.S. Geological Survey's National Water-Quality Assessment Program for the Yellowstone River Basin. Fecal-coliform concentrations ranged from 2 to 3,000 col/100 mL (colonies per 100 milliliters) for 100 samples, and Escherichia coli concentrations ranged from 1 to 2,800 col/100 mL for 97 samples. Fecal-coliform concentrations exceeded the U.S. Environmental Protection Agency's recommended limit for a single sample for recreational contact with water in 37.0 percent of the samples. Escherichia coli concentrations exceeded the U.S. Environmental Protection Agency's recommended limit for a single sample for moderate use, full-body recreational contact with water in 38.1 percent of the samples and the recommended limit for infrequent use, full-body recreational contact with water in 24.7 percent of the samples. Fecal-indicator-bacteria concentrations varied by basin. Samples from the Bighorn River Basin had the highest median concentrations for fecal coliform of 340 col/100 mL and for Escherichia coli of 300 col/100 mL. Samples from the Wind River Basin had the lowest median concentrations for fecal coliform of 50 col/100 mL and for Escherichia coli of 62 col/100 mL. Fecal-indicator-bacteria concentrations varied by land cover. Samples from sites with an urban land cover had the highest median concentrations for fecal coliform of 540 col/100 mL and for Escherichia coli of 420 col/100 mL. Maximum concentrations for fecal coliform of 3,000 col/100 mL and for Escherichia coli of 2,800 col/100 mL were in samples from sites with an agricultural land cover. The lowest median concentrations for fecal coliform of 130 col/100 mL and for Escherichia coli of 67 col/100 mL were for samples from sites with a forested land cover. A strong and positive relation existed between fecal coliform and Escherichia coli

  17. Prevalence and antibiotic-resistance characteristics of Enterococcus spp. Isolated from free-living and captive raptors in Central Illinois.

    PubMed

    Marrow, Judilee; Whittington, Julia K; Mitchell, Mark; Hoyer, Lois L; Maddox, Carol

    2009-04-01

    Due to their predatory nature, raptor species may serve as important indicators of environmental contamination with antimicrobial-resistant bacteria. Raptors prey on small rodents and birds that have diverse habitat ranges, including urban and rural environments, and their intestinal microflora can reflect that of the animals on which they feed. Enterococcus spp. were selected as target organisms because they have been isolated from the avian gastrointestinal tract, can be conferred by prey items, and because they are capable of multiple resistance patterns. They are also a concerning source of human antimicrobial resistance. In this study fecal cultures were obtained from 15 May 2004 to 31 August 2004, from 21 free-living raptors and four captive raptors. Enterococcus was isolated from 21 (84%) of the 25 birds, and 54 isolates were chosen for further study based upon unique colony morphology. The most common isolate recovered was Enterococcus faecalis (95%, 95% confidence interval [CI]: 89-100). One bird in the study was determined to have Enterococcus gallinarum. Two distinct ribotypes of E. faecalis were identified, one with unique bands at 11 and 13 kb and the other with unique bands at 14 and 20 kb. Both ribotypes were found in free-living and captive birds. The Enterococcus isolates in this study demonstrated a variety of antimicrobial-resistance characteristics, including almost complete resistance to amikacin, first-generation cephalosporins, spectinomycin, and sulphadimethoxime. Isolates demonstrated variable resistance to chloramphenicol, gentamicin, enrofloxacin, erythromycin, and ticarcillin. No phenotypically vancomycin-resistant E. faecalis isolates were recovered from any of the raptors; three isolates had intermediate level susceptibility. A significantly higher number of isolates collected from captive birds demonstrated resistance to chloramphenicol than those obtained from free-living birds. This trend was not duplicated with any of the remaining

  18. Sediment and Fecal Indicator Bacteria Loading in a Mixed Land Use Watershed: Contributions from Suspended and Bed Load Transport

    EPA Science Inventory

    Water quality studies that quantify sediment and fecal bacteria loading commonly focus on suspended contaminants transported during high flows. Fecal contaminants in bed sediments are typically ignored and need to be considered because of their potential to increase pathogen load...

  19. Associations of antimicrobial use with antimicrobial resistance in Campylobacter coli from grow-finish pigs in Japan.

    PubMed

    Ozawa, M; Makita, K; Tamura, Y; Asai, T

    2012-10-01

    To determine associations between antimicrobial use and antimicrobial resistance in Campylobacter coli, 155 isolates were obtained from the feces of apparently healthy grow-finish pigs in Japan. In addition, data on the use of antibiotics collected through the national antimicrobial resistance monitoring system in Japan were used for the analysis. Logistic regression was used to identify risk factors to antimicrobial resistance in C. coli in pigs for the following antimicrobials: ampicillin, dihydrostreptomycin, erythromycin, oxytetracycline, chloramphenicol, and enrofloxacin. The data suggested the involvement of several different mechanisms of resistance selection. The statistical relationships were suggestive of co-selection; use of macrolides was associated with enrofloxacin resistance (OR=2.94; CI(95%): 0.997, 8.68) and use of tetracyclines was associated with chloramphenicol resistance (OR=2.37; CI(95%): 1.08, 5.19). The statistical relationships were suggestive of cross-resistance: use of macrolides was associated with erythromycin resistance (OR=9.36; CI(95%): 2.96, 29.62) and the use of phenicols was associated with chloramphenicol resistance (OR=11.83; CI(95%): 1.41, 99.44). These data showed that the use of antimicrobials in pigs selects for resistance in C. coli within and between classes of antimicrobials. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Antimicrobial resistance in Libya: 1970–2011

    PubMed Central

    Ghenghesh, Khalifa Sifaw; Rahouma, Amal; Tawil, Khaled; Zorgani, Abdulaziz; Franka, Ezzedin

    2013-01-01

    Resistance to antimicrobial agents is a major health problem that affects the whole world. Providing information on the past state of antimicrobial resistance in Libya may assist the health authorities in addressing the problem more effectively in the future. Information was obtained mainly from Highwire Press (including PubMed) search for the period 1970–2011 using the terms ‘antibiotic resistance in Libya’, ‘antimicrobial resistance in Libya’, ‘tuberculosis in Libya’, and ‘primary and acquired resistance in Libya’ in title and abstract. From 1970 to 2011 little data was available on antimicrobial resistance in Libya due to lack of surveillance and few published studies. Available data shows high resistance rates for Salmonella species in the late 1970s and has remained high to the present day. High prevalence rates (54–68%) of methicillin-resistant Staphylococcus aureus (MRSA) were reported in the last decade among S. aureus from patients with burns and surgical wound infections. No reports were found of vancomycin-resistant S. aureus (VRSA) or vancomycin-intermediate-resistant S. aureus (VISA) using standard methods from Libya up to the end of 2011. Reported rates of primary (i.e. new cases) and acquired (i.e. retreatment cases) multidrug-resistant tuberculosis (MDR-TB) from the eastern region of Libya in 1971 were 16.6 and 33.3% and in 1976 were 8.6 and 14.7%, in western regions in 1984–1986 were 11 and 21.5% and in the whole country in 2011 were estimated at 3.4 and 29%, respectively. The problem of antibiotic resistance is very serious in Libya. The health authorities in particular and society in general should address this problem urgently. Establishing monitoring systems based on the routine testing of antimicrobial sensitivity and education of healthcare workers, pharmacists, and the community on the health risks associated with the problem and benefits of prudent use of antimicrobials are some steps that can be taken to tackle the

  1. Shigella Antimicrobial Drug Resistance Mechanisms, 2004-2014.

    PubMed

    Nüesch-Inderbinen, Magdalena; Heini, Nicole; Zurfluh, Katrin; Althaus, Denise; Hächler, Herbert; Stephan, Roger

    2016-06-01

    To determine antimicrobial drug resistance mechanisms of Shigella spp., we analyzed 344 isolates collected in Switzerland during 2004-2014. Overall, 78.5% of isolates were multidrug resistant; 10.5% were ciprofloxacin resistant; and 2% harbored mph(A), a plasmid-mediated gene that confers reduced susceptibility to azithromycin, a last-resort antimicrobial agent for shigellosis.

  2. Titanium surfaces immobilized with the major antimicrobial fragment FK-16 of human cathelicidin LL-37 are potent against multiple antibiotic-resistant bacteria.

    PubMed

    Mishra, Biswajit; Wang, Guangshun

    2017-08-01

    Infections on implanted medical devices are a challenging problem, especially when bacteria form difficult-to-treat biofilms. Antimicrobial peptides are considered to be a solution due to their potency against antibiotic-resistant superbugs. Previously, the authors' laboratory demonstrated the prevention of staphylococcal biofilm formation in an animal catheter model by injecting merecidin (formerly known as 17BIPHE2), a peptide engineered based on the only human cathelicidin. This study documents an alternative solution via covalent immobilization of FK-16, amino acid sequence FKRIVQRIKDFLRNLV-amide, which corresponds to the major antimicrobial region (residues 17-32) of LL-37. FK-16 is superior to the longer peptide LL-37 in terms of synthesis cost and the shorter peptide KR-12 in terms of activity spectrum. Indeed, the FK16-coated titanium surface showed a broad-spectrum activity against the ESKAPE pathogens, including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. It also demonstrated anti-adhesion and biofilm inhibition capabilities against both S. aureus and E. coli.

  3. Antimicrobial activity of methanolic extracts of Sambucus ebulus and Urtica dioica against clinical isolates of methicillin resistant Staphylococcus aureus.

    PubMed

    Salehzadeh, Ali; Asadpour, Leila; Naeemi, Akram Sadat; Houshmand, Elham

    2014-01-01

    Increase in the emergence of drug -resistant pathogens led to the development of natural antimicrobials. In this study the antimicrobial effect of methanolic extracts of Sambucus ebulus and Urtica dioica on 16 skin and wound infections isolates of methicillin resistant S. aureus have been studied. Solvent extraction procedure was done using soxhlet apparatus for extracting antimicrobial agents from freeze dried plants. Antibacterial activity was measured using agar well diffusion method. The MIC of Sambucus ebulus and Urtica dioica extracts against the standard strain of S. aureus ATCC 6538 were determined using the micro dilution method at 15 mg and 20 mg respectively. All the test bacteria were found sensitive to the Sambucus ebulus extract and only one isolate was resistant to Urtica dioica extract. Extracts of Sambucus ebulus and Urtica dioica possess antibacterial potency against MRSA isolates and may be used as a natural antiseptics and antimicrobial agents in medicine.

  4. Antibacterial activities of multi drug resistant Myroides odoratimimus bacteria isolated from adult flesh flies (Diptera: sarcophagidae) are independent of metallo beta-lactamase gene

    PubMed Central

    Dharne, M.S.; Gupta, A.K.; Rangrez, A.Y.; Ghate, H.V.; Patole, M.S.; Shouche, Y.S.

    2008-01-01

    Flesh flies (Diptera: Sarcophagidae) are well known cause of myiasis and their gut bacteria have never been studied for antimicrobial activity against bacteria. Antimicrobial studies of Myroides spp. are restricted to nosocomial strains. A Gram-negative bacterium, Myroides sp., was isolated from the gut of adult flesh flies (Sarcophaga sp.) and submitted to evaluation of nutritional parameters using Biolog GN, 16S rRNA gene sequencing, susceptibility to various antimicrobials by disc diffusion method and detection of metallo β-lactamase genes (TUS/MUS). The antagonistic effects were tested on Gram-negative and Gram-positive bacteria isolated from human clinical specimens, environmental samples and insect mid gut. Bacterial species included were Aeromonas hydrophila, A. culicicola, Morganella morganii subsp. sibonii, Ochrobactrum anthropi, Weissella confusa, Escherichia coli, Ochrobactrum sp., Serratia sp., Kestersia sp., Ignatzschineria sp., Bacillus sp. The Myroides sp. strain was resistant to penicillin-G, erythromycin, streptomycin, amikacin, kanamycin, gentamycin, ampicillin, trimethoprim and tobramycin. These strain showed antibacterial action against all bacterial strains except W. confusa, Ignatzschineria sp., A. hydrophila and M. morganii subsp. sibonii. The multidrug resistance of the strain was similar to the resistance of clinical isolates, inhibiting growth of bacteria from clinical, environmental and insect gut samples. The metallo β-lactamase (TUS/MUS) genes were absent, and resistance due to these genes was ruled out, indicating involvement of other secretion machinery. PMID:24031236

  5. Leading Antimicrobial Drug-Resistant Diseases

    MedlinePlus

    ... can be life-threatening. Find Out More MedlinePlus: Antibiotic Resistance National Institute of Allergy and Infectious Diseases: Antibiotic Resistance Centers for Disease Control and Prevention: Antibiotic / Antimicrobial ...

  6. Prevalence and antimicrobial susceptibilities of anaerobic bacteria isolated from perforated corneal ulcers by culture and multiplex PCR: an evaluation in cases with keratitis and endophthalmitis.

    PubMed

    Tokman, Hrisi Bahar; İskeleli, Güzin; Dalar, Zeynep Güngördü; Kangaba, Achille Aime; Demirci, Mehmet; Akay, Hatice K; Borsa, Bariş Ata; Algingil, Reyhan Çalişkan; Kocazeybek, Bekir S; Torun, Müzeyyen Mamal; Kiraz, Nuri

    2014-01-01

    Anaerobic bacteria play an important role in eye infections; however, there is limited epidemiologic data based on the the role of these bacteria in the etiology of keratitis and endophthalmitis. The aim of this re- search is to determine the prevalence of anaerobic bacteria in perforated corneal ulcers of patients with keratitis and endophthalmitis and to evaluate their antimicrobial susceptibilities. Corneal scrapings were taken by the ophthalmologist using sterile needles. For the isolation of anaerobic bacteria, samples were inoculated on specific media and were incubated under anaerobic conditions obtained with Anaero-Gen (Oxoid & Mitsubishi Gas Company) in anaerobic jars (Oxoid USA, Inc. Columbia, MD, USA). The molecular identification of anaerobic bacteria was performed by multiplex PCR and the susceptibilities of an- aerobic bacteria to penicillin, chloramphenicol, and clindamycin were determined with the E test (bioMerieux). 51 strains of anaerobic bacteria belonging to four different genuses were detected by multiplex PCR and only 46 strains were isolated by culture. All of them were found susceptible to chloramphenicol whereas penicillin resistance was found in 13.3% of P.anaerobius strains, clindamycin resistance was found in 34.8% of P.acnes and 13.3% of P. anaerobius strains. Additionnaly, one strain of P. granulosum was found resistant to clindamycin, one strain of B. fragilis and one strain of P.melaninogenica were found resistant to penicillin and clindamycin. Routine analyses of anaerobes in perforated corneal ulcers is inevitable and usage of appropriate molecular methods, for the detection of bacteria responsible from severe infections which might not be deter- mined by cultivation, may serve for the early decision of the appropriate treatment. Taking into account the in- creasing antimicrobial resistance of anaerobic bacteria, alternative eye specific antibiotics effective against anaer- obes are needed to achieve a successful treatment.

  7. Antimicrobial-resistant Klebsiella species isolated from free-range chicken samples in an informal settlement.

    PubMed

    Fielding, Burtram C; Mnabisa, Amanda; Gouws, Pieter A; Morris, Thureyah

    2012-02-29

    Sub-therapeutic doses of antimicrobial agents are administered routinely to poultry to aid growth and to prevent disease, with prolonged exposure often resulting in bacterial resistance. Crossover of antibiotic resistant bacteria from poultry to humans poses a risk to human health. In this study, 17 chicken samples collected from a vendor operating in an informal settlement in the Cape Town Metropolitan area, South Africa were screened for antimicrobial-resistant Gram-negative bacilli using the Kirby Bauer disk diffusion assay. IN TOTAL, SIX ANTIBIOTICS WERE SCREENED: ampicillin, ciprofloxacin, gentamicin, nalidixic acid, tetracycline and trimethoprim. Surprisingly, Klebsiella ozaenae was identified in 96 and K. rhinoscleromatis in 6 (n=102) of the samples tested. Interestingly, ∼40% of the isolated Klebsiella spp. showed multiple resistance to at least three of the six antibiotics tested. Klebsiella ozaenae and K. rhinoscleromatis cause clinical chronic rhinitis and are almost exclusively associated with people living in areas of poor hygiene.

  8. Antimicrobial resistant Escherichia coli in the municipal wastewater system: effect of hospital effluent and environmental fate.

    PubMed

    Harris, Suvi; Morris, Carol; Morris, Dearbhaile; Cormican, Martin; Cummins, Enda

    2014-01-15

    The prevalence of antimicrobial resistant (AMR) bacteria is increasing worldwide and remains a significant medical challenge which may lead to antimicrobial redundancy. The contribution of hospital effluent to the prevalence of resistance in wastewater treatment plant (WWTP) effluents is not fully understood. AMR bacteria contained in hospital effluent may be released into the aquatic and soil environments after WWTP processing. Hence, the objective of this study is to identify the extent hospital effluent contributes to contamination of these environments by comparing two WWTPs, one which receives hospital effluent and one which does not. AMR Escherichia coli were monitored in the two WWTPs. A model was developed using these monitored values to predict the effect of hospital effluent within a WWTP. The model predicted levels of AMR E. coli in the aquatic environment and potential bather exposure to AMR E. coli. The model results were highly variable. WWTP influent containing hospital effluent had a higher mean percentage of AMR E. coli; although, there appeared to be no within treatment plant effect on the prevalence of AMR E. coli. Examination of WWTP sludge showed a similar variation. There appeared to be no consistent effect from the presence of hospital effluent. The human exposure assessment model predicted swimmer intake of AMR E. coli between 6 and 193CFU/100ml sea water. It appears that hospital effluent is not the main contributing factor behind the development and persistence of AMR E. coli within WWTPs, although resistance may be too well-developed to identify an influence from hospital effluent. Mitigation needs to focus on the removal of already present resistant bacteria but for new or hospital specific antimicrobials focus needs to be on their limited release within effluents or separate treatment. © 2013.

  9. Antimicrobial Resistance of Faecal Escherichia coli Isolates from Pig Farms with Different Durations of In-feed Antimicrobial Use.

    PubMed

    Gibbons, J F; Boland, F; Egan, J; Fanning, S; Markey, B K; Leonard, F C

    2016-05-01

    Antimicrobial use and resistance in animal and food production are of concern to public health. The primary aims of this study were to determine the frequency of resistance to 12 antimicrobials in Escherichia coli isolates from 39 pig farms and to identify patterns of antimicrobial use on these farms. Further aims were to determine whether a categorization of farms based on the duration of in-feed antimicrobial use (long-term versus short-term) could predict the occurrence of resistance on these farms and to identify the usage of specific antimicrobial drugs associated with the occurrence of resistance. Escherichia coli were isolated from all production stages on these farms; susceptibility testing was carried out against a panel of antimicrobials. Antimicrobial prescribing data were collected, and farms were categorized as long term or short term based on these. Resistance frequencies and antimicrobial use were tabulated. Logistic regression models of resistance to each antimicrobial were constructed with stage of production, duration of antimicrobial use and the use of 5 antimicrobial classes included as explanatory variables in each model. The greatest frequencies of resistance were observed to tetracycline, trimethoprim/sulphamethoxazole and streptomycin with the highest levels of resistance observed in isolates from first-stage weaned pigs. Differences in the types of antimicrobial drugs used were noted between long-term and short-term use farms. Categorization of farms as long- or short-term use was sufficient to predict the likely occurrence of resistance to 3 antimicrobial classes and could provide an aid in the control of resistance in the food chain. Stage of production was a significant predictor variable in all models of resistance constructed and did not solely reflect antimicrobial use at each stage. Cross-selection and co-selection for resistance was evident in the models constructed, and the use of trimethoprim/sulphonamide drugs in particular was

  10. Antimicrobial-resistant fecal bacteria from ceftiofur-treated and nonantimicrobial-treated comingled beef cows at a cow-calf operation

    USDA-ARS?s Scientific Manuscript database

    We compared the occurrences of 3rd-generation cephalosporin-resistant (3GCr ), tetracycline-resistant (TETr) and trimethoprim-sulfamethoxazole-resistant (COTr ) Escherichia coli, 3GCr Salmonella enterica, nalidixic acid-resistant (NALr) S. enterica and erythromycin-resistant (ERYr) enterococci from ...

  11. Engineering Antimicrobials Refractory to Resistance

    USDA-ARS?s Scientific Manuscript database

    Multi-drug resistant superbugs are a persistent problem in modern health care, demonstrating the need for a new class of antimicrobials that can address this concern. Triple-acting peptidoglycan hydrolase fusions are a novel class of antimicrobials which have qualities well suited to avoiding resis...

  12. Marine Antimicrobial Peptides: Nature Provides Templates for the Design of Novel Compounds against Pathogenic Bacteria

    PubMed Central

    Falanga, Annarita; Lombardi, Lucia; Franci, Gianluigi; Vitiello, Mariateresa; Iovene, Maria Rosaria; Morelli, Giancarlo; Galdiero, Massimiliano; Galdiero, Stefania

    2016-01-01

    The discovery of antibiotics for the treatment of bacterial infections brought the idea that bacteria would no longer endanger human health. However, bacterial diseases still represent a worldwide treat. The ability of microorganisms to develop resistance, together with the indiscriminate use of antibiotics, is mainly responsible for this situation; thus, resistance has compelled the scientific community to search for novel therapeutics. In this scenario, antimicrobial peptides (AMPs) provide a promising strategy against a wide array of pathogenic microorganisms, being able to act directly as antimicrobial agents but also being important regulators of the innate immune system. This review is an attempt to explore marine AMPs as a rich source of molecules with antimicrobial activity. In fact, the sea is poorly explored in terms of AMPs, but it represents a resource with plentiful antibacterial agents performing their role in a harsh environment. For the application of AMPs in the medical field limitations correlated to their peptide nature, their inactivation by environmental pH, presence of salts, proteases, or other components have to be solved. Thus, these peptides may act as templates for the design of more potent and less toxic compounds. PMID:27213366

  13. Marine Antimicrobial Peptides: Nature Provides Templates for the Design of Novel Compounds against Pathogenic Bacteria.

    PubMed

    Falanga, Annarita; Lombardi, Lucia; Franci, Gianluigi; Vitiello, Mariateresa; Iovene, Maria Rosaria; Morelli, Giancarlo; Galdiero, Massimiliano; Galdiero, Stefania

    2016-05-21

    The discovery of antibiotics for the treatment of bacterial infections brought the idea that bacteria would no longer endanger human health. However, bacterial diseases still represent a worldwide treat. The ability of microorganisms to develop resistance, together with the indiscriminate use of antibiotics, is mainly responsible for this situation; thus, resistance has compelled the scientific community to search for novel therapeutics. In this scenario, antimicrobial peptides (AMPs) provide a promising strategy against a wide array of pathogenic microorganisms, being able to act directly as antimicrobial agents but also being important regulators of the innate immune system. This review is an attempt to explore marine AMPs as a rich source of molecules with antimicrobial activity. In fact, the sea is poorly explored in terms of AMPs, but it represents a resource with plentiful antibacterial agents performing their role in a harsh environment. For the application of AMPs in the medical field limitations correlated to their peptide nature, their inactivation by environmental pH, presence of salts, proteases, or other components have to be solved. Thus, these peptides may act as templates for the design of more potent and less toxic compounds.

  14. Analysis of Antimicrobial Resistance Genes Detected in MDR Salmonella enterica Serovar Typhimurium animal isolates from the National Antimicrobial Resistance Monitoring System

    USDA-ARS?s Scientific Manuscript database

    Background: The presence of Multi-Drug Resistant (MDR) Salmonella in food animals is concerning. To understand how antimicrobial resistance (AR) develops, the genetic elements responsible for MDR phenotypes in Salmonella animal isolates were investigated. National Antimicrobial Resistance Monitoring...

  15. Lack of direct effects of agrochemicals on zoonotic pathogens and fecal indicator bacteria.

    PubMed

    Staley, Zachery R; Senkbeil, Jacob K; Rohr, Jason R; Harwood, Valerie J

    2012-11-01

    Agrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of Escherichia coli, Enterococcus faecalis, Salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect.

  16. Effect of swine manure application timing on the persistence and transport of antibiotic-resistant Enterococcus and resistance genes

    USDA-ARS?s Scientific Manuscript database

    Swine manure applied to agricultural fields may lead to the transport of antibiotic resistant bacteria and antibiotic resistance genes to freshwater systems. Enterococci were studied because they are fecal indicator bacteria associated with manure. Resistance genes include genes from live cells, dea...

  17. Antibiotic development challenges: the various mechanisms of action of antimicrobial peptides and of bacterial resistance

    PubMed Central

    Guilhelmelli, Fernanda; Vilela, Nathália; Albuquerque, Patrícia; Derengowski, Lorena da S.; Silva-Pereira, Ildinete; Kyaw, Cynthia M.

    2013-01-01

    Antimicrobial peptides (AMPs) are natural antibiotics produced by various organisms such as mammals, arthropods, plants, and bacteria. In addition to antimicrobial activity, AMPs can induce chemokine production, accelerate angiogenesis, and wound healing and modulate apoptosis in multicellular organisms. Originally, their antimicrobial mechanism of action was thought to consist solely of an increase in pathogen cell membrane permeability, but it has already been shown that several AMPs do not modulate membrane permeability in the minimal lethal concentration. Instead, they exert their effects by inhibiting processes such as protein and cell wall synthesis, as well as enzyme activity, among others. Although resistance to these molecules is uncommon several pathogens developed different strategies to overcome AMPs killing such as surface modification, expression of efflux pumps, and secretion of proteases among others. This review describes the various mechanisms of action of AMPs and how pathogens evolve resistance to them. PMID:24367355

  18. Quantifying Antimicrobial Resistance at Veal Calf Farms

    PubMed Central

    Bosman, Angela B.; Wagenaar, Jaap; Stegeman, Arjan; Vernooij, Hans; Mevius, Dik

    2012-01-01

    This study was performed to determine a sampling strategy to quantify the prevalence of antimicrobial resistance on veal calf farms, based on the variation in antimicrobial resistance within and between calves on five farms. Faecal samples from 50 healthy calves (10 calves/farm) were collected. From each individual sample and one pooled faecal sample per farm, 90 selected Escherichia coli isolates were tested for their resistance against 25 mg/L amoxicillin, 25 mg/L tetracycline, 0.5 mg/L cefotaxime, 0.125 mg/L ciprofloxacin and 8/152 mg/L trimethoprim/sulfamethoxazole (tmp/s) by replica plating. From each faecal sample another 10 selected E. coli isolates were tested for their resistance by broth microdilution as a reference. Logistic regression analysis was performed to compare the odds of testing an isolate resistant between both test methods (replica plating vs. broth microdilution) and to evaluate the effect of pooling faecal samples. Bootstrap analysis was used to investigate the precision of the estimated prevalence of resistance to each antimicrobial obtained by several simulated sampling strategies. Replica plating showed similar odds of E. coli isolates tested resistant compared to broth microdilution, except for ciprofloxacin (OR 0.29, p≤0.05). Pooled samples showed in general lower odds of an isolate being resistant compared to individual samples, although these differences were not significant. Bootstrap analysis showed that within each antimicrobial the various compositions of a pooled sample provided consistent estimates for the mean proportion of resistant isolates. Sampling strategies should be based on the variation in resistance among isolates within faecal samples and between faecal samples, which may vary by antimicrobial. In our study, the optimal sampling strategy from the perspective of precision of the estimated levels of resistance and practicality consists of a pooled faecal sample from 20 individual animals, of which 90 isolates are

  19. C-terminal Lysine-Linked Magainin 2 with Increased Activity Against Multidrug-Resistant Bacteria.

    PubMed

    Lorenzón, Esteban N; Santos-Filho, Norival A; Ramos, Matheus A S; Bauab, Tais M; Camargo, Ilana L B C; Cilli, Eduardo M

    2016-01-01

    Due to the growing problem of antibiotic-resistant microorganisms, the development of novel antimicrobial agents is a very important challenge. Dimerization of cationic antimicrobial peptides (cAMPs) is a potential strategy for enhancing antimicrobial activity. Here, we studied the effects of magainin 2 (MG2) dimerization on its structure and biological activity. Lysine and glutamic acid were used to synthesize the C- and N-terminal dimers of MG2, respectively, in order to evaluate the impact of linker position used to obtain the dimers. Both MG2 and its dimeric versions showed a random coil structure in aqueous solution. However, in the presence of a structure-inducing solvent or a membrane mimetic, all peptides acquired helical structure. N-terminal dimerization did not affect the biological activity of the peptide. On the other hand, the C-terminal dimer, (MG2)2K, showed antimicrobial activity 8-16 times higher than that of MG2, and the time required to kill Escherichia coli was lower. The enhanced antimicrobial activity was related to membrane permeabilization. (MG2)2K was also more active against multidrug-resistant bacteria of clinical origin. Overall, the results presented here demonstrate that C-terminal lysine-linked dimerization improve the activity of MG2, and (MG2)2K can be considered as a potential antimicrobial agent.

  20. Advances in pharmacovigilance initiatives surrounding antimicrobial resistance-Indian perspective.

    PubMed

    Bairy, Laxminarayana Kurady; Nayak, Veena; A, Avinash; Kunder, Sushil Kiran

    2016-08-01

    In recent years the development of antimicrobial resistance has been accelerating, the discovery of new antimicrobial agents has slowed substantially in past decades. This review mainly focuses on the problem of antimicrobial resistance(AMR); the various contributor mechanisms, consequences and future of AMR. The review also highlights the irrational use of antimicrobials, improving their usage and problems associated with pharmacovigilance of antimicrobial resistance. Pharmacovigilance in the form of surveillance of antibiotic use is being done in 90% of the countries worldwide through the WHONET program developed by WHO. However, the data comes from a limited area of the globe. Data from every part of the world is required, so that there is geographical representation of every region. A major hurdle in quantifying the extent of antimicrobial resistance is the fact that there are several known microbes, that may turn out to be resistant to one or more of the several known antimicrobial agents. The global action plan initiated by WHO, if implemented successfully will definitely reduce AMR and will help in evaluating treatment interventions.

  1. Prevalence of bacteria resistant to antibiotics and/or biocides on meat processing plant surfaces throughout meat chain production.

    PubMed

    Lavilla Lerma, Leyre; Benomar, Nabil; Gálvez, Antonio; Abriouel, Hikmate

    2013-02-01

    In order to investigate the prevalence of resistant bacteria to biocides and/or antibiotics throughout meat chain production from sacrifice till end of production line, samples from various surfaces of a goat and lamb slaughterhouse representative of the region were analyzed by the culture dependent approach. Resistant Psychrotrophs (n=255 strains), Pseudomonas sp. (n=166 strains), E. coli (n=23 strains), Staphylococcus sp. (n=17 strains) and LAB (n=82 represented mainly by Lactobacillus sp.) were isolated. Resistant psychrotrophs and pseudomonads (47 and 29%, respectively) to different antimicrobials were frequently detected in almost all areas of meat processing plant regardless the antimicrobial used, although there was a clear shift in the spectrum of other bacterial groups and for this aim such resistance was determined according to several parameters: antimicrobial tested, sampling zone and the bacterial group. Correlation of different parameters was done using a statistical tool "Principal component analysis" (PCA) which determined that quaternary ammonium compounds and hexadecylpyridinium were the most relevant biocides for resistance in Pseudomonas sp., while ciprofloxacin and hexachlorophene were more relevant for psychrotrophs, LAB, and in lesser extent Staphylococcus sp. and Escherichia coli. On the other hand, PCA of sampling zones determined that sacrifice room (SR) and cutting room (CR) considered as main source of antibiotic and/or biocide resistant bacteria showed an opposite behaviour concerning relevance of antimicrobials to determine resistance being hexadecylpyridinium, cetrimide and chlorhexidine the most relevant in CR, while hexachlorophene, oxonia 6P and PHMG the most relevant in SR. In conclusion, rotational use of the relevant biocides as disinfectants in CR and SR is recommended in an environment which is frequently disinfected. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. What happens in hospitals does not stay in hospitals: antibiotic-resistant bacteria in hospital wastewater systems.

    PubMed

    Hocquet, D; Muller, A; Bertrand, X

    2016-08-01

    Hospitals are hotspots for antimicrobial-resistant bacteria (ARB) and play a major role in both their emergence and spread. Large numbers of these ARB will be ejected from hospitals via wastewater systems. In this review, we present quantitative and qualitative data of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, vancomycin-resistant enterococci and Pseudomonas aeruginosa in hospital wastewaters compared to community wastewaters. We also discuss the fate of these ARB in wastewater treatment plants and in the downstream environment. Published studies have shown that hospital effluents contain ARB, the burden of these bacteria being dependent on their local prevalence. The large amounts of antimicrobials rejected in wastewater exert a continuous selective pressure. Only a few countries recommend the primary treatment of hospital effluents before their discharge into the main wastewater flow for treatment in municipal wastewater treatment plants. Despite the lack of conclusive data, some studies suggest that treatment could favour the ARB, notably ESBL-producing E. coli. Moreover, treatment plants are described as hotspots for the transfer of antibiotic resistance genes between bacterial species. Consequently, large amounts of ARB are released in the environment, but it is unclear whether this release contributes to the global epidemiology of these pathogens. It is reasonable, nevertheless, to postulate that it plays a role in the worldwide progression of antibiotic resistance. Antimicrobial resistance should now be seen as an 'environmental pollutant', and new wastewater treatment processes must be assessed for their capability in eliminating ARB, especially from hospital effluents. Copyright © 2016. Published by Elsevier Ltd.

  3. Characterization of antimicrobial resistant Escherichia coli isolated from processed bison carcasses.

    PubMed

    Li, Q; Sherwood, J S; Logue, C M

    2007-12-01

    To determine the phenotypic and genotypic antimicrobial susceptibility profiles of Escherichia coli from bison carcasses. The antimicrobial resistance of 138 E. coli isolates recovered from processed bison carcasses was determined by using the National Antimicrobial Resistance Monitoring System panels, polymerase chain reaction assays, plasmid analysis and conjugation studies. Resistance to 14 of the 16 antimicrobials was observed. Twenty-three (16.7%) isolates displayed resistance to at least one antimicrobial agent. The most prevalent resistances were to tetracycline (13.0%), sulfamethoxazole (7.9%) and streptomycin (5.8%). No resistance was observed to amikacin and ciprofloxacin. Further analysis of 23 antimicrobial-resistant E. coli isolates showed the presence of resistance genes corresponding to their phenotypic profiles. Results of conjugation studies carried out showed most isolates tested were able to transfer their resistance to recipients. This study indicated that multidrug-resistant E. coli isolates are present in bison. However, the resistance rate is lower than that reported in other meat species. The beneficial effects of antimicrobial-free feeding practice in bison may be promoting a reduction in the prevalence of antimicrobial resistance in commensal flora of bison.

  4. Antimicrobial and Herbal Drug Resistance in Enteric Bacteria Isolated from Faecal Droppings of Common House Lizard/Gecko (Hemidactylus frenatus).

    PubMed

    Singh, Bhoj R; Singh, Vidya; Ebibeni, N; Singh, Raj K

    2013-01-01

    From 194 faecal dropping samples of common house geckos collected from offices (60), houses (88), integrated farm units (IFS,18) and hostels, guest houses, and dining rooms of different canteen/mess (HGM, 28), 326 bacterial isolates of enteric bacteria belonging to 17 genera and 34 species were detected. Escherichia coli were the most frequently (39) isolated followed by Citrobacter freundii (33), Klebsiella pneumonia (27), Salmonella indica (12), Enterobacter gergoviae (12), and Ent. agglomerans (11). Other important bacteria isolated from gecko droppings were Listonella damsela (2), Raoultella terrigena (3), S. salamae (2), S. houtenae (3), Edwardsiella tarda (4), Edwardsiella hoshinae (1), and Klebsiella oxytoca (2). Of the 223 isolates tested for antimicrobial drug sensitivity, 27 (12.1%) had multiple drug resistance (MDR). None of the salmonellae or edwardsiellae had MDR however, MDR strains were significantly more common among Escherichia spp. (P = 1.9 × 10(-5)) and isolates from IFS units (P = 3.58 × 10(-23)). The most effective herbal drug, Ageratum conyzoides extract, inhibited growth of only 27.8% of strains tested followed by ethanolic extract of Zanthoxylum rhetsa (13.9%), eucalyptus oil (5.4%), patchouli oil (5.4%), lemongrass oil (3.6%), and sandalwood oil (3.1%), and Artemisia vulgaris essential oil (3.1%).

  5. Application of SELECT and SWAT models to simulate source load, fate, and transport of fecal bacteria in watersheds.

    NASA Astrophysics Data System (ADS)

    Ranatunga, T.

    2017-12-01

    Modeling of fate and transport of fecal bacteria in a watershed is a processed based approach that considers releases from manure, point sources, and septic systems. Overland transport with water and sediments, infiltration into soils, transport in the vadose zone and groundwater, die-off and growth processes, and in-stream transport are considered as the other major processes in bacteria simulation. This presentation will discuss a simulation of fecal indicator bacteria source loading and in-stream conditions of a non-tidal watershed (Cedar Bayou Watershed) in South Central Texas using two models; Spatially Explicit Load Enrichment Calculation Tool (SELECT) and Soil and Water Assessment Tool (SWAT). Furthermore, it will discuss a probable approach of bacteria source load reduction in order to meet the water quality standards in the streams. The selected watershed is listed as having levels of fecal indicator bacteria that posed a risk for contact recreation and wading by the Texas Commission of Environmental Quality (TCEQ). The SELECT modeling approach was used in estimating the bacteria source loading from land categories. Major bacteria sources considered were, failing septic systems, discharges from wastewater treatment facilities, excreta from livestock (Cattle, Horses, Sheep and Goat), excreta from Wildlife (Feral Hogs, and Deer), Pet waste (mainly from Dogs), and runoff from urban surfaces. The estimated source loads from SELECT model were input to the SWAT model, and simulate the bacteria transport through the land and in-stream. The calibrated SWAT model was then used to estimate the indicator bacteria in-stream concentrations for future years based on regional land use, population and household forecast (up to 2040). Based on the reductions required to meet the water quality standards in-stream, the corresponding required source load reductions were estimated.

  6. Antimicrobial resistance: from global agenda to national strategic plan, Thailand.

    PubMed

    Tangcharoensathien, Viroj; Sattayawutthipong, Wanchai; Kanjanapimai, Sukhum; Kanpravidth, Wantanee; Brown, Richard; Sommanustweechai, Angkana

    2017-08-01

    In Thailand, antimicrobial resistance has formed a small component of national drug policies and strategies on emerging infectious diseases. However, poor coordination and a lack of national goals and monitoring and evaluation platforms have reduced the effectiveness of the corresponding national actions. On the basis of local evidence and with the strong participation of relevant stakeholders, the first national strategic plan on antimicrobial resistance has been developed in Thailand. Before the development of the plan, ineffective coordination meant that antimicrobial resistance profiles produced at sentinel hospitals were not used effectively for clinical decision-making. There was no integrated system for the surveillance of antimicrobial resistance, no system for monitoring consumption of antimicrobial drugs by humans, livestock and pets and little public awareness of antimicrobial resistance. In August 2016, the Thai government endorsed a national strategic plan on antimicrobial resistance that comprised six strategic actions and five targets. A national steering committee guides the plan's implementation and a module to assess the prevalence of household antibiotic use and antimicrobial resistance awareness has been embedded into the biennial national health survey. A national system for the surveillance of antimicrobial consumption has also been initiated. Strong political commitment, national ownership and adequate multisectoral institutional capacities will be essential for the effective implementation of the national plan. A robust monitoring and evaluation platform now contributes to evidence-based interventions. An integrated system for the surveillance of antimicrobial resistance still needs to be established.

  7. Lack of Direct Effects of Agrochemicals on Zoonotic Pathogens and Fecal Indicator Bacteria

    PubMed Central

    Staley, Zachery R.; Senkbeil, Jacob K.; Rohr, Jason R.

    2012-01-01

    Agrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of Escherichia coli, Enterococcus faecalis, Salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect. PMID:22961900

  8. On-farm starling populations and other environmental and management factors associated with the presence of cefotaxime and ciprofloxacin resistant E. coli among dairy cattle in Ohio.

    PubMed

    Medhanie, Genet A; Pearl, David L; McEwen, Scott A; Guerin, Michele T; Jardine, Claire M; Schrock, Jennifer; LeJeune, Jeffrey T

    2016-11-01

    Wild birds that forage around livestock facilities have been implicated as vectors of antimicrobial resistant organisms. Although antimicrobial resistant bacteria have been isolated from European starlings (Sturnus vulgaris), their role in the dissemination of antimicrobial resistant elements in livestock facilities needs further investigation. To determine whether on-farm starling density and other factors were associated with the presence of cefotaxime and ciprofloxacin resistant E. coli among dairy cows in Ohio, bovine fecal pats from 150 farms were tested for the presence of cefotaxime and ciprofloxacin resistant E. coli. Each farm was visited twice (during the summer and fall of 2007-2009). Multi-level logistic regression models with a random intercept to account for fecal pats collected within a specific visit to a farm were used to assess the associations. The percentage of samples with cefotaxime and ciprofloxacin resistant E. coli was 13.4% and 13.6%, respectively. The percentage of farms having at least one sample testing positive for cefotaxime and ciprofloxacin resistant E. coli was 56.7% and 48.7%, respectively. The odds of detecting cefotaxime and ciprofloxacin resistant E. coli in the samples was significantly higher in 2007 compared to 2008 and 2009, in fall compared to summer, and from farms closer than 60km to starling night roost sites compared to the farms further than 60km. The presence of starlings during the day had a negative association with the likelihood of detecting cefotaxime resistant E. coli. Presence of calves also had a negative association with the likelihood of detecting both cefotaxime and ciprofloxacin resistant E. coli. European starlings might play a role in the dissemination of antimicrobial resistant agents in livestock facilities related to their daily population movements rather than the specific density of birds on farm during the day. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. INTERNAL AMPLIFICATION CONTROL FOR USE IN QUANTITATIVE POLYMERASE CHAIN REACTION FECAL INDICATOR BACTERIA ASSAYS

    EPA Science Inventory

    Quantitative polymerase chain reaction (QPCR) can be used as a rapid method for detecting fecal indicator bacteria. Because false negative results can be caused by PCR inhibitors that co-extract with the DNA samples, an internal amplification control (IAC) should be run with eac...

  10. Interlaboratory Comparison of Real-time PCR Protocols for Quantification of General Fecal Indicator Bacteria

    EPA Science Inventory

    The application of quantitative real-time PCR (qPCR) technologies for the rapid identification of fecal bacteria in environmental waters is being considered for use as a national water quality metric in the United States. The transition from research tool to a standardized proto...

  11. Systematic analysis of funding awarded for antimicrobial resistance research to institutions in the UK, 1997-2010.

    PubMed

    Head, Michael G; Fitchett, Joseph R; Cooke, Mary K; Wurie, Fatima B; Atun, Rifat; Hayward, Andrew C; Holmes, Alison; Johnson, Alan P; Woodford, Neil

    2014-02-01

    To assess the level of research funding awarded to UK institutions specifically for antimicrobial resistance-related research and how closely the topics funded relate to the clinical and public health burden of resistance. Databases and web sites were systematically searched for information on how infectious disease research studies were funded for the period 1997-2010. Studies specifically related to antimicrobial resistance, including bacteriology, virology, mycology and parasitology research, were identified and categorized in terms of funding by pathogen and disease and by a research and development value chain describing the type of science. The overall dataset included 6165 studies receiving a total investment of £2.6 billion, of which £102 million was directed towards antimicrobial resistance research (5.5% of total studies, 3.9% of total spend). Of 337 resistance-related projects, 175 studies focused on bacteriology (40.2% of total resistance-related spending), 42 focused on antiviral resistance (17.2% of funding) and 51 focused on parasitology (27.4% of funding). Mean annual funding ranged from £1.9 million in 1997 to £22.1 million in 2009. Despite the fact that the emergence of antimicrobial resistance threatens our future ability to treat many infections, the proportion of the UK infection-research spend targeting this important area is small. There are encouraging signs of increased investment in this area, but it is important that this is sustained and targeted at areas of projected greatest burden. Two areas of particular concern requiring more investment are tuberculosis and multidrug-resistant Gram-negative bacteria.

  12. Ciprofloxacin residue and antibiotic-resistant biofilm bacteria in hospital effluent.

    PubMed

    Ory, Jérôme; Bricheux, Geneviève; Togola, Anne; Bonnet, Jean Louis; Donnadieu-Bernard, Florence; Nakusi, Laurence; Forestier, Christiane; Traore, Ousmane

    2016-07-01

    Discharge of antimicrobial residues and resistant bacteria in hospital effluents is supposed to have strong impacts on the spread of antibiotic resistant bacteria in the environment. This study aimed to characterize the effluents of the Gabriel Montpied teaching hospital, Clermont-Ferrand, France, by simultaneously measuring the concentration of ciprofloxacin and of biological indicators resistant to this molecule in biofilms formed in the hospital effluent and by comparing these data to ciprofloxacin consumption and resistant bacterial isolates of the hospital. Determination of the measured environmental concentration of ciprofloxacin by spot sampling and polar organic chemical integrative (POCIS) sampling over 2 weeks, and comparison with predicted environmental concentrations produced a hazard quotient >1, indicating a potential ecotoxicological risk. A negative impact was also observed with whole hospital effluent samples using the Tetrahymena pyriformis biological model. During the same period, biofilms were formed within the hospital effluent, and analysis of ciprofloxacin-resistant isolates indicated that Gamma-Proteobacteria were numerous, predominantly Aeromonadaceae (69.56%) and Enterobacteriaceae (22.61%). Among the 115 isolates collected, plasmid-mediated fluoroquinolone-resistant genes were detected, with mostly aac(6')-lb-cr and qnrS. In addition, 60% of the isolates were resistant to up to six antibiotics, including molecules mostly used in the hospital (aminosides and third-generation cephalosporins). In parallel, 1247 bacteria isolated from hospitalized patients and resistant to at least one of the fluoroquinolones were collected. Only 5 of the 14 species identified in the effluent biofilm were also found in the clinical isolates, but PFGE typing of the Gram-negative isolates found in both compartments showed there was no clonality among the strains. Altogether, these data confirm the role of hospital loads as sources of pollution for wastewater

  13. Antimicrobial resistance of Listeria spp. recovered from processed bison.

    PubMed

    Li, Q; Sherwood, J S; Logue, C M

    2007-01-01

    The current study examined the antimicrobial susceptibility of 86 Listeria spp. isolated from processed bison carcasses. Susceptibility to 25 antimicrobial agents was determined using E-test and National Antimicrobial Resistance Monitoring System (NARMS) panels. Most Listeria isolates (88-98%) exhibited resistance to bacitracin, oxacillin, cefotaxime, and fosfomycin. Resistance to tetracycline (18.6%) was also common. Of the 16 tetracycline-resistant Listeria isolates, 15 carried tetM and 2 contained integrase of Tn1545 transposons. Rifampicin and trimethoprim-sulfamethoxazole were the most active antimicrobial agents against Listeria spp., with a MIC(90) of 0.38 microg ml(-1). Ampicillin, erythromycin, penicillin, gentamicin, and tobramycin also exhibited good activity against Listeria spp., with MIC(90) not exceeding 1 microg ml(-1). Differences in resistance among Listeria spp. was displayed, as Listeria innocua strains were more resistant than other Listeria species. The study showed that Listeria monocytogenes strains from bison were susceptible to the antibiotics most commonly used to treat human listeriosis. However, the presence of antimicrobial resistance in L. innocua indicates the potential for transfer of resistance and a conjugative transposon to L. monocytogenes. The findings of our study will provide useful information for the development of public health policy in the use of antimicrobials in food animal production.

  14. Farm-level associations with the shedding of Salmonella and antimicrobial-resistant Salmonella in U.S. dairy cattle.

    PubMed

    Habing, Greg G; Lombard, Jason E; Kopral, Christine A; Dargatz, David A; Kaneene, John B

    2012-09-01

    Salmonella enterica is the leading cause of foodborne-related deaths and hospitalizations within the United States. Infections caused by antimicrobial-resistant (AMR) strains are associated with higher hospital costs and case fatality. The objective for this study was to determine the association of management practices with the recovery of Salmonella and AMR Salmonella on dairy herds. Individual adult cow fecal samples and/or composite fecal samples were collected from 265 dairy herds in 17 states. Samples were cultured for Salmonella, and the MIC was determined for 15 antimicrobials. Herds were classified as Salmonella positive if at least one isolate was recovered, and AMR Salmonella positive if at least one resistant isolate was recovered. Questionnaires regarding management practices were administered to herd operators, and a subset of practices was selected based on subject knowledge and prior research. Data on preventive and therapeutic antimicrobial usage were included in the analysis. Logistic regression models were used to determine which practices were significantly (p<0.05) associated with each herd classification. A total of 124 and 25 herds were classified as Salmonella positive and AMR Salmonella positive, respectively. Variables significantly associated with Salmonella-positive herds included using sprinklers or misters for heat abatement (OR=2.8; CI: 1.6-4.9), feeding anionic salts to cows (OR=1.9; CI: 1.1-3.5), and feeding ionophores to cows (OR=2.1; CI: 1.2-3.7). Herds that used a broadcast/solid spread had lower odds (OR=0.26; CI: 0.11-0.63) of being Salmonella positive. Herds with at least one resistant isolate were more likely to have used composted/dried manure for bedding relative to herds with only susceptible isolates (OR=3.6; CI: 1.2-11.0). These results can be useful to focus additional research aimed at decreasing the prevalence of Salmonella and AMR Salmonella on U.S. dairy herds.

  15. Antimicrobials in small-scale urban pig farming in a lower middle-income country - arbitrary use and high resistance levels.

    PubMed

    Ström, G; Boqvist, S; Albihn, A; Fernström, L-L; Andersson Djurfeldt, A; Sokerya, S; Sothyra, T; Magnusson, U

    2018-01-01

    Administration of antimicrobials to food-producing animals is regarded as a major contributor to the overall emergence of resistance in bacteria worldwide. However, few data are available on global antimicrobial use and resistance (AMR) in livestock, especially from low- and middle-income countries. We conducted a structured survey of 91 small-scale pig farms in the urban and peri-urban areas of Phnom Penh, Cambodia, to assess the farmers' knowledge, attitudes and practices related to antimicrobial use in their pig production. Commensal Escherichia coli was isolated from three healthy pigs from each farm ( n  = 261) and susceptibility testing was performed against 14 antimicrobials, using broth microdilution. Univariable logistic regression and generalized linear mixed models were used to investigate potential associations between farm characteristics, management factors and resistance to different types of antimicrobials. We found a widespread and arbitrary use of antimicrobials, often based on the farmer's own judgment. Around 66% of the farmers reported frequently self-adjusting treatment duration and dosage, and 45% had not heard about the term 'antimicrobial resistance'. The antimicrobials most commonly mentioned or kept by the farmers were amoxicillin, tylosin, gentamicin and colistin. Around 37% used a feed concentrate that contained antimicrobials, while antimicrobials for humans were used as a last-line treatment by 10% of the farmers. Commensal E. coli exhibited high prevalence of resistance to several antimicrobials considered to be of critical importance for human medicine, including ampicillin, ciprofloxacin and colistin, and multidrug-resistance was found in 79% of the samples. Higher prevalence of resistance was observed on farms that administered prophylactic antimicrobials and on farms that treated the entire group or herd in the event of disease. The widespread and arbitrary use of antimicrobials in pig farming in Cambodia is highly worrisome

  16. The sludge loading rate regulates the growth and release of heterotrophic bacteria resistant to six types of antibiotics in wastewater activated sludge.

    PubMed

    Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

    2015-01-01

    Wastewater treatment plants are considered as hot reservoirs of antimicrobial resistance. However, the fates of antibiotic-resistant bacteria during biological treatment processes and relevant influencing factors have not been fully understood. This study evaluated the effects of the sludge loading rate on the growth and release of six kinds of antibiotic-resistant bacteria in an activated sludge system. The results indicated that higher sludge loading rates amplified the growth of all six types of antibiotic resistant bacteria. The release of most antibiotic-resistant bacteria through both the effluent and biosolids was amplified with increased sludge loading rate. Biosolids were the main pattern for all antibiotic-resistant bacteria release in an activated sludge system, which was determined primarily by their growth in the activated sludge. A higher sludge loading rate reactor tended to retain more antibiotic resistance. An activated sludge system with lower sludge loading rates was considered more conducive to the control of antibiotic resistance.

  17. Antimicrobial Peptides in 2014

    PubMed Central

    Wang, Guangshun; Mishra, Biswajit; Lau, Kyle; Lushnikova, Tamara; Golla, Radha; Wang, Xiuqing

    2015-01-01

    This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms. PMID:25806720

  18. Probable secondary transmission of antimicrobial-resistant Escherichia coli between people living with and without pets

    PubMed Central

    CHUNG, Yeon Soo; PARK, Young Kyung; PARK, Yong Ho; PARK, Kun Taek

    2017-01-01

    Companion animals are considered as one of the reservoirs of antimicrobial-resistant (AR) bacteria that can be cross-transmitted to humans. However, limited information is available on the possibility of AR bacteria originating from companion animals being transmitted secondarily from owners to non-owners sharing the same space. To address this issue, the present study investigated clonal relatedness among AR E. coli isolated from dog owners and non-owners in the same college classroom or household. Anal samples (n=48) were obtained from 14 owners and 34 non-owners; 31 E. coli isolates were collected (nine from owners and 22 from non-owners). Of 31 E. coli, 20 isolates (64.5%) were resistant to at least one antimicrobial, and 16 isolates (51.6%) were determined as multi-drug resistant E. coli. Six isolates (19.4%) harbored integrase genes (five harbored class I integrase gene and one harbored class 2 integrase gene, respectively). Pulsed-field gel electrophoretic analysis identified three different E. coli clonal sets among isolates, indicating that cross-transmission of AR E. coli can easily occur between owners and non-owners. The findings emphasize a potential risk of spread of AR bacteria originating from pets within human communities, once they are transferred to humans. Further studies are needed to evaluate the exact risk and identify the risk factors of secondarily transmission by investigating larger numbers of isolates from pets, their owners and non-owners in a community. PMID:28190823

  19. Probable secondary transmission of antimicrobial-resistant Escherichia coli between people living with and without pets.

    PubMed

    Chung, Yeon Soo; Park, Young Kyung; Park, Yong Ho; Park, Kun Taek

    2017-03-18

    Companion animals are considered as one of the reservoirs of antimicrobial-resistant (AR) bacteria that can be cross-transmitted to humans. However, limited information is available on the possibility of AR bacteria originating from companion animals being transmitted secondarily from owners to non-owners sharing the same space. To address this issue, the present study investigated clonal relatedness among AR E. coli isolated from dog owners and non-owners in the same college classroom or household. Anal samples (n=48) were obtained from 14 owners and 34 non-owners; 31 E. coli isolates were collected (nine from owners and 22 from non-owners). Of 31 E. coli, 20 isolates (64.5%) were resistant to at least one antimicrobial, and 16 isolates (51.6%) were determined as multi-drug resistant E. coli. Six isolates (19.4%) harbored integrase genes (five harbored class I integrase gene and one harbored class 2 integrase gene, respectively). Pulsed-field gel electrophoretic analysis identified three different E. coli clonal sets among isolates, indicating that cross-transmission of AR E. coli can easily occur between owners and non-owners. The findings emphasize a potential risk of spread of AR bacteria originating from pets within human communities, once they are transferred to humans. Further studies are needed to evaluate the exact risk and identify the risk factors of secondarily transmission by investigating larger numbers of isolates from pets, their owners and non-owners in a community.

  20. Adaptive Resistance to Biocides in Salmonella enterica and Escherichia coli O157 and Cross-Resistance to Antimicrobial Agents

    PubMed Central

    Braoudaki, M.; Hilton, A. C.

    2004-01-01

    The mechanisms by which bacteria resist killing by antibiotics and biocides are still poorly defined, although repeated exposure to sublethal concentrations of antibacterial agents undoubtedly contributes to their development. This study aimed both to investigate the potential of Salmonella enterica and Escherichia coli O157 for adaptive resistance to commonly used biocides and to determine any cross-resistance to antibiotics. Strains were repeatedly passaged in media containing increasing concentrations of a biocide or antibiotic until adaptive resistance was obtained. A wide panel of antimicrobial agents was then screened by using the adapted strain to determine cross-resistance, if any. Adaptive resistance was readily achieved for both S. enterica and E. coli O157. Cross-resistance in adaptively resistant S. enterica varied with the serotype; Salmonella enterica serovar Enteritidis expressed cross-resistance to chloramphenicol, whereas Salmonella enterica serovar Typhimurium expressed cross-resistance to chlorhexidine. Benzalkonium chloride-resistant Salmonella enterica serovar Virchow showed elevated resistance to chlorhexidine; however, chlorhexidine-resistant Salmonella serovar Virchow did not demonstrate reciprocal cross-resistance to benzalkonium chloride, suggesting specific rather than generic resistance mechanisms. E. coli O157 strains acquired high levels of resistance to triclosan after only two sublethal exposures and, when adapted, repeatedly demonstrated decreased susceptibilities to various antimicrobial agents, including chloramphenicol, erythromycin, imipenem, tetracycline, and trimethoprim, as well as to a number of biocides. These observations raise concern over the indiscriminate and often inappropriate use of biocides, especially triclosan, in situations where they are unnecessary, whereby they may contribute to the development of microbial resistance mechanisms. PMID:14715734

  1. Salmonella enterica subclinical infection: bacteriological, serological, pulsed-field gel electrophoresis, and antimicrobial resistance profiles--longitudinal study in a three-site farrow-to-finish farm.

    PubMed

    Vigo, German B; Cappuccio, Javier A; Piñeyro, Pablo E; Salve, Angela; Machuca, Mariana A; Quiroga, Maria A; Moredo, Fabiana; Giacoboni, Gabriel; Cancer, Jose L; Caffer, Ines G; Binsztein, Norma; Pichel, Mariana; Perfumo, Carlos J

    2009-10-01

    The aim of this surveillance was to study both Salmonella spp. shedding patterns and the time course of serological response in farrow-to-finish reared pigs from a subclinically infected farm. Antimicrobial resistance profile, molecular subtyping, and the relationship among the isolates were determined by pulsed-field gel electrophoresis (PFGE). A farrow-to-finish farm of 6000 sows, with a history of Salmonella Typhimurium septicemia, was selected. A longitudinal bacteriological and serological study was conducted in 25 sows before farrowing (M/S1) and in 50 offspring at 21 (M/S2), 35 (M/S3), 65 (M/S4), 86 (M/S5), 128 (M/S6), and 165 (M/S7) days of age. Serum antibodies were tested using Herdcheck((R)) Swine Salmonella antibody test kit (Idexx Laboratories, ME). Bacteria were isolated from pooled fecal samples. Suspected isolates were confirmed by conventional biochemical assays, and those identified as Salmonella spp. were serotyped. A variation between seropositive percentages and positive fecal samples was observed. Serologically positive pigs decreased from S1 to S4, and subsequently increased from S4 to S7. The percentages of fecal positive culture increased from M1 to M3, and then declined in M4, increased in M5, and were negative in M6 and M7. In the study three serovars, Salmonella 3,10:e,h:-, Salmonella Muenster, and Salmonella Bovismorbificans, were identified with low pathogenicity for swine. Three multidrug resistance strains (one belonged to Salmonella 3,10:e,h:- and two belonged to Salmonella Muenster) were found. PFGE results showed three different but closely related patterns among the 13 isolates of Salmonella Bovismorbificans, and two patterns for the three Salmonella Muenster and Salmonella 3,10:e,h:- isolates. This longitudinal study established critical points of Salmonella spp. infection in the farm and the production stages, where appropriate control measures must be taken. PFGE showed clonal relationships in each serovar. Antibiotic

  2. Salmonella enterica Subclinical Infection: Bacteriological, Serological, Pulsed-Field Gel Electrophoresis, and Antimicrobial Resistance Profiles—Longitudinal Study in a Three-Site Farrow-to-Finish Farm

    PubMed Central

    Vigo, German B.; Cappuccio, Javier A.; Salve, Angela; Machuca, Mariana A.; Quiroga, Maria A.; Moredo, Fabiana; Giacoboni, Gabriel; Cancer, Jose L.; Caffer, Ines G.; Binsztein, Norma; Pichel, Mariana; Perfumo, Carlos J.

    2009-01-01

    Abstract The aim of this surveillance was to study both Salmonella spp. shedding patterns and the time course of serological response in farrow-to-finish reared pigs from a subclinically infected farm. Antimicrobial resistance profile, molecular subtyping, and the relationship among the isolates were determined by pulsed-field gel electrophoresis (PFGE). A farrow-to-finish farm of 6000 sows, with a history of Salmonella Typhimurium septicemia, was selected. A longitudinal bacteriological and serological study was conducted in 25 sows before farrowing (M/S1) and in 50 offspring at 21 (M/S2), 35 (M/S3), 65 (M/S4), 86 (M/S5), 128 (M/S6), and 165 (M/S7) days of age. Serum antibodies were tested using Herdcheck® Swine Salmonella antibody test kit (Idexx Laboratories, ME). Bacteria were isolated from pooled fecal samples. Suspected isolates were confirmed by conventional biochemical assays, and those identified as Salmonella spp. were serotyped. A variation between seropositive percentages and positive fecal samples was observed. Serologically positive pigs decreased from S1 to S4, and subsequently increased from S4 to S7. The percentages of fecal positive culture increased from M1 to M3, and then declined in M4, increased in M5, and were negative in M6 and M7. In the study three serovars, Salmonella 3,10:e,h:-, Salmonella Muenster, and Salmonella Bovismorbificans, were identified with low pathogenicity for swine. Three multidrug resistance strains (one belonged to Salmonella 3,10:e,h:- and two belonged to Salmonella Muenster) were found. PFGE results showed three different but closely related patterns among the 13 isolates of Salmonella Bovismorbificans, and two patterns for the three Salmonella Muenster and Salmonella 3,10:e,h:- isolates. This longitudinal study established critical points of Salmonella spp. infection in the farm and the production stages, where appropriate control measures must be taken. PFGE showed clonal relationships in each serovar. Antibiotic

  3. Costs and length of stay associated with antimicrobial resistance in acute kidney injury patients with bloodstream infection.

    PubMed

    Vandijck, D M; Blot, S I; Decruyenaere, J M; Vanholder, R C; De Waele, J J; Lameire, N H; Claus, S; De Schuijmer, J; Dhondt, A W; Verschraegen, G; Hoste, E A

    2008-01-01

    Antimicrobial resistance negatively impacts on prognosis. Intensive care unit (ICU) patients, and particularly those with acute kidney injury (AKI), are at high risk for developing nosocomial bloodstream infections (BSI) due to multi-drug-resistant strains. Economic implications in terms of costs and length of stay (LOS) attributable to antimicrobial resistance are underevaluated. This study aimed to assess whether microbial susceptibility patterns affect costs and LOS in a well-defined cohort of ICU patients with AKI undergoing renal replacement therapy (RRT) who developed nosocomial BSI. Historical study (1995-2004) enrolling all adult RRT-dependent ICU patients with AKI and nosocomial BSI. Costs were considered as invoiced in the Belgian reimbursement system, and LOS was used as a surrogate marker for hospital resource allocation. Of the 1330 patients with AKI undergoing RRT, 92 had microbiologic evidence of nosocomial BSI (57/92, 62% due to a multi-drug-resistant microorganism). Main patient characteristics were equal in both groups. As compared to patients with antimicro-4 bial-susceptible BSI, patients with antimicrobial-resistant BSI were more likely to acquire Gram-positive infection (72.6% vs 25.5%, P<0.001). No differences were found neither in LOS (ICU before BSI, ICU, hospital before BSI, hospital, hospital after BSI, and time on RRT; all P>0.05) or hospital costs (all P>0.05) when comparing patients with antimicrobial-resistant vs antimicrobial-susceptible BSI. However, although not statistically significant, patients with BSI caused by resistant Gram-negative-, Candida-, or anaerobic bacteria incurred substantial higher costs than those without. In a cohort of ICU patients with AKI and nosocomial BSI undergoing RRT, patients with antimicrobial-resistant vs antimicrobial-susceptible Gram-positive BSI did not have longer hospital stays, or higher hospital costs. Patients with resistant "other" (i.e. Gram-negative, Candida, or anaerobic) BSI were found

  4. PCR detection and quantitation of predominant anaerobic bacteria in human and animal fecal samples.

    PubMed Central

    Wang, R F; Cao, W W; Cerniglia, C E

    1996-01-01

    PCR procedures based on 16S rRNA gene sequences specific for 12 anaerobic bacteria that predominate in the human intestinal tract were developed and used for quantitative detection of these species in human (adult and baby) feces and animal (rat, mouse, cat, dog, monkey, and rabbit) feces. Fusobacterium prausnitzii, Peptostreptococcus productus, and Clostridium clostridiiforme had high PCR titers (the maximum dilutions for positive PCR results ranged from 10(-3) to 10(-8)) in all of the human and animal fecal samples tested. Bacteroides thetaiotaomicron, Bacteroides vulgatus, and Eubacterium limosum also showed higher PCR titers (10(-2) to 10(-6)) in adult human feces. The other bacteria tested, including Escherichia coli, Bifidobacterium adolescentis, Bifidobacterium longum, Lactobacillus acidophilus, Eubacterium biforme, and Bacteroides distasonis, were either at low PCR titers (less than 10(-2)) or not detected by PCR. The reported PCR procedure including the fecal sample preparation method is simplified and rapid and eliminates the DNA isolation steps. PMID:8919784

  5. Predicting Fecal Indicator Bacteria Concentrations in the South Fork Broad River Watershed Using Virtual Beach

    EPA Science Inventory

    Virtual Beach (VB) is a decision support tool that constructs site-specific statistical models to predict fecal indicator bacteria (FIB) at recreational beaches. Although primarily designed for making decisions regarding beach closures or issuance of swimming advisories based on...

  6. Antimicrobial and Efflux Pump Inhibitory Activity of Caffeoylquinic Acids from Artemisia absinthium against Gram-Positive Pathogenic Bacteria

    PubMed Central

    Fiamegos, Yiannis C.; Kastritis, Panagiotis L.; Exarchou, Vassiliki; Han, Haley; Bonvin, Alexandre M. J. J.; Vervoort, Jacques; Lewis, Kim; Hamblin, Michael R.; Tegos, George P.

    2011-01-01

    Background Traditional antibiotics are increasingly suffering from the emergence of multidrug resistance amongst pathogenic bacteria leading to a range of novel approaches to control microbial infections being investigated as potential alternative treatments. One plausible antimicrobial alternative could be the combination of conventional antimicrobial agents/antibiotics with small molecules which block multidrug efflux systems known as efflux pump inhibitors. Bioassay-driven purification and structural determination of compounds from plant sources have yielded a number of pump inhibitors which acted against gram positive bacteria. Methodology/Principal Findings In this study we report the identification and characterization of 4′,5′-O-dicaffeoylquinic acid (4′,5′-ODCQA) from Artemisia absinthium as a pump inhibitor with a potential of targeting efflux systems in a wide panel of Gram-positive human pathogenic bacteria. Separation and identification of phenolic compounds (chlorogenic acid, 3′,5′-ODCQA, 4′,5′-ODCQA) was based on hyphenated chromatographic techniques such as liquid chromatography with post column solid-phase extraction coupled with nuclear magnetic resonance spectroscopy and mass spectroscopy. Microbial susceptibility testing and potentiation of well know pump substrates revealed at least two active compounds; chlorogenic acid with weak antimicrobial activity and 4′,5′-ODCQA with pump inhibitory activity whereas 3′,5′-ODCQA was ineffective. These intitial findings were further validated with checkerboard, berberine accumulation efflux assays using efflux-related phenotypes and clinical isolates as well as molecular modeling methodology. Conclusions/Significance These techniques facilitated the direct analysis of the active components from plant extracts, as well as dramatically reduced the time needed to analyze the compounds, without the need for prior isolation. The calculated energetics of the docking poses supported the

  7. Prudent Use of Antimicrobials in Exotic Animal Medicine.

    PubMed

    Broens, Els M; van Geijlswijk, Ingeborg M

    2018-05-01

    Reduction of antimicrobial use can result in reduction of resistance in commensal bacteria. In exotic animals, information on use of antimicrobials and resistance in commensals and pathogens is scarce. However, use of antimicrobials listed as critically important antimicrobials for human medicine seems high in exotic animals. Ideally, the selection of a therapy should be based on an accurate diagnosis and antimicrobial susceptibility testing. When prescribing antimicrobials based on empiricism, knowledge of the most common pathogens causing specific infections and the antimicrobial spectrum of antimicrobial agents is indispensable. Implementing antimicrobial stewardship promotes the prudent use of antimicrobials in exotic animals. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Impact of ertapenem on antimicrobial resistance in a sentinel group of Gram-negative bacilli: a 6 year antimicrobial resistance surveillance study.

    PubMed

    Rodriguez-Osorio, Carlos A; Sanchez-Martinez, Cesar O; Araujo-Melendez, Javier; Criollo, Elia; Macias-Hernandez, Alejandro E; Ponce-de-Leon, Alfredo; Ponce-de-Leon, Sergio; Sifuentes-Osornio, Jose

    2015-03-01

    To determine the association between ertapenem and resistance of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii-calcoaceticus complex to different antimicrobials while adjusting for relevant hospital factors. This was a retrospective time-series study conducted at a tertiary care centre from September 2002 to August 2008. The specific impact of ertapenem on the resistance of these Gram-negative bacilli (GNB) was assessed by multiple linear regression analysis, adjusting for the average length of stay, rate of hospital-acquired infections and use of 10 other antimicrobials, including type 2 carbapenems. Unadjusted analyses revealed significant increases over the duration of the study in the number of GNB resistant to meropenem/imipenem among 1000 isolates each of E. coli (0.46 ± 0.22, P < 0.05), P. aeruginosa (6.26 ± 2.26, P < 0.05), K. pneumoniae (8.06 ± 1.50, P < 0.0005) and A. baumannii-calcoaceticus complex (25.39 ± 6.81, P < 0.0005). Increased resistance to cefepime (and other extended-spectrum cephalosporins) was observed in E. coli (9.55 ± 1.45, P < 0.0005) and K. pneumoniae (15.21 ± 2.42, P < 0.0005). A. baumannii-calcoaceticus complex showed increased resistance to all antimicrobials except amikacin. After controlling for confounders, ertapenem was not significantly associated (P > 0.05) with changes in resistance for any pathogen/antimicrobial combination. After controlling for confounders, ertapenem was not associated with changes in resistance in a group of sentinel GNB, although significant variations in resistance to different antimicrobials were observed in the unadjusted analyses. These results emphasize the importance of implementation of local resistance surveillance platforms and stewardship programmes to combat the global emergence and spread of antimicrobial resistance. © The Author 2014. Published by Oxford University Press on behalf of the

  9. Phytotherapy as an alternative to conventional antimicrobials: combating microbial resistance.

    PubMed

    Enioutina, Elena Yu; Teng, Lida; Fateeva, Tatyana V; Brown, Jessica C S; Job, Kathleen M; Bortnikova, Valentina V; Krepkova, Lubov V; Gubarev, Michael I; Sherwin, Catherine M T

    2017-11-01

    In the modern antimicrobial era, the rapid spread of resistance to antibiotics and introduction of new and mutating viruses is a global concern. Combating antimicrobial resistant microbes (AMR) requires coordinated international efforts that incorporate new conventional antibiotic development as well as development of alternative drugs with antimicrobial activity, management of existing antimicrobials, and rapid detection of AMR pathogens. Areas covered: This manuscript discusses some conventional strategies to control microbial resistance. The main purpose of the manuscript is to present information on specific herbal medicines that may serve as good treatment alternatives to conventional antimicrobials for infections sensitive to conventional as well as resistant strains of microorganisms. Expert commentary: Identification of potential new antimicrobials is challenging; however, one source for potential structurally diverse and complex antimicrobials are natural products. Natural products may have advantages over other post-germ theory antimicrobials. Many antimicrobial herbal medicines possess simultaneous antibacterial, antifungal, antiprotozoal and/or antiviral properties. Herbal products have the potential to boost host resistance to infections, particularly in immunocompromised patients. Antimicrobial broad-spectrum activity in conjunction with immunostimulatory properties may help to prevent microbial resistance to herbal medicine. As part of the efforts to broaden use of herbal medicines to treat microbial infections, pre-clinical and clinical testing guidelines of these compounds as a whole should be implemented to ensure consistency in formulation, efficacy and safety.

  10. Recovery of resistant bacteria from mattresses of patients under contact precautions.

    PubMed

    Viana, Roberta El Hariri; dos Santos, Simone G; Oliveira, Adriana C

    2016-04-01

    Microorganisms may contaminate hospital mattresses even after terminal cleaning. We investigated the recovery of resistant bacteria from the mattresses of patients under contact precautions at a university hospital. We conducted a cross-sectional study. Samples were obtained from the surface of mattresses, spread on replicate organism detection and counting plates, and cultivated at 37°C for 48 hours. After collecting samples, we identified microorganisms and tested for antimicrobial susceptibility using the Vitek 2 (bioMérieux SA, Marcy-l'Etoile, France) automation system. We evaluated 51 mattresses. A total of 26 had resistant bacteria on the surface; the predominant species were Acinetobacter baumannii (69.2%), Klebsiella pneumoniae (11.5%), and Pseudomonas aeruginosa (11.5%). The median length of hospital stay was 41 days; the bed occupancy for patients under contact precautions and the time at which the patient was diagnosed as a carrier of resistant bacteria was 18 days. The phenotypic similarity of A baumannii in inpatient units (mattresses) suggests circulation of the same strain. These results highlight the importance of controlling the potential spread of microorganisms through hospital mattresses. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  11. 5-Nitroimidazole-derived Schiff bases and their copper(II) complexes exhibit potent antimicrobial activity against pathogenic anaerobic bacteria.

    PubMed

    Oliveira, Alexandre A; Oliveira, Ana P A; Franco, Lucas L; Ferencs, Micael O; Ferreira, João F G; Bachi, Sofia M P S; Speziali, Nivaldo L; Farias, Luiz M; Magalhães, Paula P; Beraldo, Heloisa

    2018-05-07

    In the present work a family of novel secnidazole-derived Schiff base compounds and their copper(II) complexes were synthesized. The antimicrobial activities of the compounds were evaluated against clinically important anaerobic bacterial strains. The compounds exhibited in vitro antibacterial activity against Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides vulgatus, Bacteroides ovatus, Parabacteroides distasonis and Fusubacterium nucleatum pathogenic anaerobic bacteria. Upon coordination to copper(II) the antibacterial activity significantly increased in several cases. Some derivatives were even more active than the antimicrobial drugs secnidazole and metronidazole. Therefore, the compounds under study are suitable for in vivo evaluation and the microorganisms should be classified as susceptible to them. Electrochemical studies on the reduction of the nitro group revealed that the compounds show comparable reduction potentials, which are in the same range of the bio-reducible drugs secnidazole and benznidazole. The nitro group reduction potential is more favorable for the copper(II) complexes than for the starting ligands. Hence, the antimicrobial activities of the compounds under study might in part be related to intracellular bio-reduction activation. Considering the increasing resistance rates of anaerobic bacteria against a wide range of antimicrobial drugs, the present work constitutes an important contribution to the development of new antibacterial drug candidates.

  12. Effect of hospitalization and antimicrobial therapy on antimicrobial resistance of colonizing Staphylococcus epidermidis.

    PubMed

    Knauer, Ariane; Fladerer, Petra; Strempfl, Christina; Krause, Robert; Wenisch, Christoph

    2004-07-31

    Endogenous infections with multi-resistant S. epidermidis are among the leading causes of nosocomial infections. The effect of hospitalization and antimicrobial therapy on antimicrobial resistance of colonizing staphylococci was determined from swabs of the nose, hand, axilla and groin from 157 patients on one day. Hospitalization for >72 hours, compared with <72 hours, was associated with a higher percentage of isolates resistant to oxacillin (56% versus 19%), gentamicin (40% versus 15%), trimethoprim (36% versus 17%), clindamycin (56% versus 17%), and fusidic acid (20% versus 4%; p < 0.01 for all), but not to rifampicin (6% versus 1%) or fosfomycin (43% versus 34%, p > 0.05 for both). Concurrent antimicrobial therapy resulted in increased resistance to oxacillin (61% versus 28%), gentamicin (43% versus 20%), and clindamycin (60% versus 26%; p < 0.01 for all), but not to trimethoprim (39% versus 23%), fusidic acid (19% versus 9%), rifampicin (6% versus 3%), or fosfomycin (46% versus 38%, p > 0.05 for all). The increase in resistant isolates was not independent, since hospitalization and antimicrobial therapy were correlated (p < 0.001). After adjustment for potential risk factors such as diabetes mellitus, central venous catheters, and hemodialysis, the odds ratio for oxacillin resistance was 2.8-3.6. None of the risk factors showed statistically significant results, except for the presence of neoplastic disease, which had a significant interaction (P=0.035). The within-subgroup odds ratios for patients with and without neoplasm were 4.2 (95% CI, 2.3-5.7) and 2.1 (95% CI, 0.78-3.12), respectively. These results show that hospitalization for more than three days, with or without antimicrobial therapy, and the presence of neoplastic disease are associated with increased antimicrobial resistance in colonizing S. epidermidis.

  13. Pathogen and antimicrobial resistance profiles of culture-proven neonatal sepsis in Southwest China, 1990-2014.

    PubMed

    Lu, Qi; Zhou, Min; Tu, Yan; Yao, Yao; Yu, Jialin; Cheng, Shupeng

    2016-10-01

    Neonatal sepsis (NS) sustains high mortality and morbidity in China, but data on the epidemiology and antimicrobial resistance patterns of NS pathogens are limited. The clinical features, aetiology and antimicrobial resistance of culture-proven NS were analysed over a period of 25 years in the metropolitan city of Chongqing in Southwest China. The occurrence rates of neonatal early-onset sepsis (EOS) were found to gradually decrease while late-onset sepsis (LOS) was kept stable from 1990 to 2014. Although coagulase-negative staphylococcus (CoNS) sepsis accounted for most infections, the occurrence rates of CoNS sepsis gradually decreased, especially in EOS. Escherichia coli and Klebsiella were common Gram-negative bacteria. The occurrence rates of E. coli and Klebsiella remained stable in EOS; however, in LOS, those had increased mildly, especially from 2009 to 2014. Although a high-degree resistance to common first- and second-line antimicrobials was observed for the main causative pathogens of NS, the gentamicin-resistance rate declined gradually from the year 2003. Similarly, the ceftazidime-resistance rate of E. coli dropped gradually from the year 2007. The alarmingly high degree of antibiotic resistance calls for urgent evaluation and development of antibiotic policy and protocols for the treatment of NS. Clinicians should strictly control the antibiotics use, decrease invasive manipulations and shorten hospitalisation to prevent LOS. © 2016 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

  14. First report on rapid screening of nanomaterial-based antimicrobial agents against β-lactamase resistance using pGLO plasmid transformed Escherichia coli HB 101 K-12

    NASA Astrophysics Data System (ADS)

    Raj, M. Alpha; Muralidhar, Y.; Sravanthi, M.; Prasad, T. N. V. K. V.; Nissipriya, M.; Reddy, P. Sirisha; Neelima, T. Shoba; Reddy, G. Dilip; Adilaxmamma, K.; Kumar, P. Anand; Krishna, T. Giridhara

    2016-08-01

    Combating antibiotic resistance requires discovery of novel antimicrobials effective against resistant bacteria. Herein, we present for the first time, pGLO plasmid transformed Escherichia coli HB 101 K 12 as novel model for screening of nanomaterial-based antimicrobial agents against β-lactamase resistance. E. coli HB 101 was transformed by pGLO plasmid in the presence of calcium chloride (50 mM; pH 6.1) aided by heat shock (0-42-0 °C). The transformed bacteria were grown on Luria-Bertani agar containing ampicillin (amp) and arabinose (ara). The transformed culture was able to grow in the presence of ampicillin and also exhibited fluorescence under UV light. Both untransformed and transformed bacteria were used for screening citrate-mediated nanosilver (CNS), aloin-mediated nanosilver (ANS), 11-α-keto-boswellic acid (AKBA)-mediated nanosilver (BNS); nanozinc oxide, nanomanganese oxide (NMO) and phytochemicals such as aloin and AKBA. Minimum inhibitory concentrations (MIC) were obtained by microplate method using ρ-iodo nitro tetrazolium indicator. All the compounds were effective against transformed bacteria except NMO and AKBA. Transformed bacteria exhibited reverse cross resistance against aloin. ANS showed the highest antibacterial activity with a MIC of 0.32 ppm followed by BNS (10.32 ppm), CNS (20.64 ppm) and NZO (34.83 ppm). Thus, pGLO plasmid can be used to induce resistance against β-lactam antibiotics and the model can be used for rapid screening of new antibacterial agents effective against resistant bacteria.

  15. Characterization of Salmonella enterica serovar Agona slaughter isolates from the animal arm of the National Antimicrobial Resistance Monitoring System-Enteric Bacteria (NARMS): 1997 through 2003.

    PubMed

    Douris, Aphrodite; Fedorka-Cray, Paula J; Jackson, Charlene R

    2008-03-01

    A total of 499 Salmonella enterica serovar Agona isolates from cattle, swine, chicken, and turkey samples were assayed for antimicrobial susceptibility and subtyped using pulsed-field gel electrophoresis (PFGE). Salmonella Agona isolates exhibited increased resistance to amoxicillin/clavulanic acid, ampicillin, cefoxitin, ceftiofur, cephalothin, and chloramphenicol, and a single isolate was resistant to ceftriaxone. Multiple drug resistance (MDR; resistance >or= 2 antimicrobials) was exhibited in 57% (n=282/499) of the Salmonella Agona isolates and 22% (n=111/499) of these Salmonella Agona isolates were resistant to five or more antimicrobials. PFGE patterns of 482 Salmonella Agona slaughter samples resulted in 165 unique patterns. Cluster analysis indicated that isolates indistinguishable by PFGE appeared to group according to antimicrobial resistance profiles. These data suggest that Salmonella Agona is increasing in prevalence in U.S. cattle presented for slaughter and should be further monitored.

  16. [Surveillance report of drug-resistant bacteria from 2007 to 2012 in Saga Prefecture, Japan (the second report)].

    PubMed

    Kiyosuke, Makiko; Nagasawa, Zenzo; Hotta, Taeko; Utsumi, Takashi; Kang, Dongchon; Miyamoto, Hiroshi

    2014-06-01

    Drug-resistant bacteria are a problematic issue in Japan. Surveillance of drug-resistant bacteria is important because the frequency of isolation and kinds of such bacteria vary between hospitals and local areas. This study summarizes the results of detection of drug-resistant bacteria in Saga Prefecture from July 2007 to June 2012. Data presented in this study were collected through questionnaire survey that was conducted in 12 hospitals. Frequency of drug-resistant bacteria are as follows: 62.5% of Staphylococcus aureus was methicillin-resistant S. aureus (MRSA); 62.2% of Streptococcus pneumoniae was penicillin-intermediate S. pneumoniae (PISP) or penicillin-resistant S. pneumoniae (PRSP); 26.4% of Haemophilus influenzae was beta-lactamase negative ampicillin-resistant H. influenzae (BLNAR); 0.5% of Pseudomonas aeruginosa was metallo-beta-lactamase (MBL) P. aeruginosa; 0.5% of P. aeruginosa was multi-drug resistant P. aeruginosa (MDRP); 12.9% and 5.1% of Escherichia coli and Klebsiella pneumoniae, respectively, were extended-spectrum beta-lactamase (ESBL) producing organisms. While the isolation frequencies of MRSA and PISP/PRSP were unchanged, those of BLNAR, ESBL producing E. coli and ESBL producing K. pneumoniae raised from 15.4% to 34.2%, from 5.7% to 18.4% and from 2.6% to 8.2%, respectively, over the past 5 years. The frequencies of isolation of MDRP and two drug resistant P. aeruginosa declined. This study revealed that the overall trend in the long-term changes of isolation frequency of drug-resistant bacteria in Saga Prefecture is similar to the trend in the national data. It also showed that the frequency and kinds of drug-resistant bacteria are variable between hospitals and local areas. Further study, such as examination of the usage and MIC value of antimicrobial drugs, will enable us to gain more detailed information on the drug-resistant bacteria.

  17. Herd-level relationship between antimicrobial use and presence or absence of antimicrobial resistance in gram-negative bovine mastitis pathogens on Canadian dairy farms.

    PubMed

    Saini, Vineet; McClure, J T; Scholl, Daniel T; DeVries, Trevor J; Barkema, Herman W

    2013-08-01

    Concurrent data on antimicrobial use (AMU) and resistance are needed to contain antimicrobial resistance (AMR) in bacteria. The present study examined a herd-level association between AMU and AMR in Escherichia coli (n=394) and Klebsiella species (n=139) isolated from bovine intramammary infections and mastitis cases on 89 dairy farms in 4 regions of Canada [Alberta, Ontario, Québec, and Maritime Provinces (Prince Edward Island, Nova Scotia, and New Brunswick)]. Antimicrobial use data were collected using inventory of empty antimicrobial containers and antimicrobial drug use rate was calculated to quantify herd-level AMU. Minimum inhibitory concentrations (MIC) were determined using Sensititre National Antimicrobial Resistance Monitoring System (NARMS) gram-negative MIC plate (Trek Diagnostic Systems Inc., Cleveland, OH). Isolates were classified as susceptible, intermediate, or resistant. Intermediate and resistant category isolates were combined to form an AMR category, and multivariable logistic regression models were built to determine herd-level odds of AMR to tetracycline, ampicillin, cefoxitin, chloramphenicol, trimethoprim-sulfamethoxazole combination, sulfisoxazole, streptomycin and kanamycin in E. coli isolates. In the case of Klebsiella species isolates, logistic regression models were built for tetracycline and sulfisoxazole; however, no associations between AMU and AMR in Klebsiella species were observed. Ampicillin-intermediate or -resistant E. coli isolates were associated with herds that used intramammarily administered cloxacillin, penicillin-novobiocin combination, and cephapirin used for dry cow therapy [odds ratios (OR)=26, 32, and 189, respectively], and intramammary ceftiofur administered for lactating cow therapy and systemically administered penicillin (OR=162 and 2.7, respectively). Use of systemically administered penicillin on a dairy farm was associated with tetracycline and streptomycin-intermediate or -resistant E. coli isolates (OR=5

  18. The Establishment of the Colombian Integrated Program for Antimicrobial Resistance Surveillance (COIPARS): A Pilot Project on Poultry Farms, Slaughterhouses and Retail Market.

    PubMed

    Donado-Godoy, P; Castellanos, R; León, M; Arevalo, A; Clavijo, V; Bernal, J; León, D; Tafur, M A; Byrne, B A; Smith, W A; Perez-Gutierrez, E

    2015-04-01

    The development of antimicrobial resistance among bacteria (AMR) is currently one of the world's most pressing public health problems. The use of antimicrobial agents in humans and animals has resulted in AMR which has narrowed the potential use of antibiotics for the treatment of infections in humans. To monitor AMR and to develop control measures, some countries, such as the USA, Canada and Denmark, have established national integrated surveillance systems (FDA, , CIPARS, 2007, DANMAP,2002). The components of these programs monitor changes in susceptibility/resistance to antimicrobial agents of selected zoonotic pathogens and commensal organisms recovered from animals, retail meats and humans. The rapid development of Colombia's animal production industry has raised food safety issues including the emergence of antibiotic resistance. The Colombian Integrated Surveillance Program for Antimicrobial Resistance (COIPARS) was established as a pilot project to monitor AMR on poultry farms, slaughter houses and retail markets. © 2015 Blackwell Verlag GmbH.

  19. Does the wide use of quaternary ammonium compounds enhance the selection and spread of antimicrobial resistance and thus threaten our health?

    PubMed

    Hegstad, Kristin; Langsrud, Solveig; Lunestad, Bjørn Tore; Scheie, Anne Aamdal; Sunde, Marianne; Yazdankhah, Siamak P

    2010-06-01

    Quaternary ammonium compounds (QACs) are widely used biocides that possess antimicrobial effect against a broad range of microorganisms. These compounds are used for numerous industrial purposes, water treatment, antifungal treatment in horticulture, as well as in pharmaceutical and everyday consumer products as preserving agents, foam boosters, and detergents. Resistance toward QACs is widespread among a diverse range of microorganisms and is facilitated by several mechanisms such as modifications in the membrane composition, expression of stress response and repair systems, or expression of efflux pump genes. Development of resistance in both pathogenic and nonpathogenic bacteria has been related to application in human medicine and the food industry. QACs in cosmetic products will inevitably come into intimate contact with the skin or mucosal linings in the mouth and thus are likely to add to the selection pressure toward more QAC-resistant microorganisms among the skin or mouth flora. There is increasing evidence of coresistance and cross-resistance between QACs and a range of other clinically important antibiotics and disinfectants. Use of QACs may have driven the fixation and spread of certain resistance cassette collectors (class 1 integrons), currently responsible for a major part of antimicrobial resistance in gram-negative bacteria. More indiscriminate use of QACs such as in cosmetic products may drive the selection of further new genetic elements that will aid in the persistence and spread of antimicrobial resistance and thus in limiting our treatment options for microbial infections.

  20. Efficacy of triclosan as an antimicrobial hand soap and its potential impact on antimicrobial resistance: a focused review.

    PubMed

    Giuliano, Christopher A; Rybak, Michael J

    2015-03-01

    Triclosan is a synthetic biocide found in many household products, including antimicrobial hand soap. Levels of triclosan have been found throughout the environment and in human urine, blood, and even breast milk. Increasing levels of exposure to triclosan have led to concerns over the development of resistance to triclosan and cross-resistance to other antimicrobials. We performed a literature search to assess whether the widespread use of triclosan displays a favorable benefit: risk ratio, defined by evaluation of triclosan's efficacy as an antimicrobial hand soap and its potential effect on the development of antimicrobial resistance. Data from laboratory-based studies regarding the efficacy of triclosan are conflicting, although well-designed studies suggest no significant difference in efficacy over nonantimicrobial soap. In addition, when triclosan was introduced in a community setting, no beneficial effects were observed on the reduction of infections over nonantimicrobial soap. Resistance to triclosan and cross-resistance to antimicrobials have been consistently demonstrated in laboratory settings, although overall resistance rates and cross-resistance rates in the community setting are low. Based on the available evidence, the risk of potential antimicrobial resistance outweighs the benefit of widespread triclosan use in antimicrobial soaps. © 2015 Pharmacotherapy Publications, Inc.