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Sample records for antibiotic susceptibility profiles

  1. Resistance mutations generate divergent antibiotic susceptibility profiles against translation inhibitors

    PubMed Central

    Cocozaki, Alexis I.; Altman, Roger B.; Huang, Jian; Buurman, Ed T.; Kazmirski, Steven L.; Doig, Peter; Prince, D. Bryan; Blanchard, Scott C.; Cate, Jamie H. D.; Ferguson, Andrew D.

    2016-01-01

    Mutations conferring resistance to translation inhibitors often alter the structure of rRNA. Reduced susceptibility to distinct structural antibiotic classes may, therefore, emerge when a common ribosomal binding site is perturbed, which significantly reduces the clinical utility of these agents. The translation inhibitors negamycin and tetracycline interfere with tRNA binding to the aminoacyl-tRNA site on the small 30S ribosomal subunit. However, two negamycin resistance mutations display unexpected differential antibiotic susceptibility profiles. Mutant U1060A in 16S Escherichia coli rRNA is resistant to both antibiotics, whereas mutant U1052G is simultaneously resistant to negamycin and hypersusceptible to tetracycline. Using a combination of microbiological, biochemical, single-molecule fluorescence transfer experiments, and X-ray crystallography, we define the specific structural defects in the U1052G mutant 70S E. coli ribosome that explain its divergent negamycin and tetracycline susceptibility profiles. Unexpectedly, the U1052G mutant ribosome possesses a second tetracycline binding site that correlates with its hypersusceptibility. The creation of a previously unidentified antibiotic binding site raises the prospect of identifying similar phenomena in antibiotic-resistant pathogens in the future. PMID:27382179

  2. Resistance mutations generate divergent antibiotic susceptibility profiles against translation inhibitors.

    PubMed

    Cocozaki, Alexis I; Altman, Roger B; Huang, Jian; Buurman, Ed T; Kazmirski, Steven L; Doig, Peter; Prince, D Bryan; Blanchard, Scott C; Cate, Jamie H D; Ferguson, Andrew D

    2016-07-19

    Mutations conferring resistance to translation inhibitors often alter the structure of rRNA. Reduced susceptibility to distinct structural antibiotic classes may, therefore, emerge when a common ribosomal binding site is perturbed, which significantly reduces the clinical utility of these agents. The translation inhibitors negamycin and tetracycline interfere with tRNA binding to the aminoacyl-tRNA site on the small 30S ribosomal subunit. However, two negamycin resistance mutations display unexpected differential antibiotic susceptibility profiles. Mutant U1060A in 16S Escherichia coli rRNA is resistant to both antibiotics, whereas mutant U1052G is simultaneously resistant to negamycin and hypersusceptible to tetracycline. Using a combination of microbiological, biochemical, single-molecule fluorescence transfer experiments, and X-ray crystallography, we define the specific structural defects in the U1052G mutant 70S E. coli ribosome that explain its divergent negamycin and tetracycline susceptibility profiles. Unexpectedly, the U1052G mutant ribosome possesses a second tetracycline binding site that correlates with its hypersusceptibility. The creation of a previously unidentified antibiotic binding site raises the prospect of identifying similar phenomena in antibiotic-resistant pathogens in the future. PMID:27382179

  3. Comprehensive antibiotic susceptibility profiling of Chilean Piscirickettsia salmonis field isolates.

    PubMed

    Henríquez, P; Kaiser, M; Bohle, H; Bustos, P; Mancilla, M

    2016-04-01

    Antibiotics have been extensively used against infections produced by Piscirickettsia salmonis, a fish pathogen and causative agent of piscirickettsiosis and one of the major concerns for the Chilean salmon industry. Therefore, the emergence of resistant phenotypes is to be expected. With the aim of obtaining a landscape of the antimicrobial resistance of P. salmonis in Chile, the susceptibility profiles for quinolones, florfenicol and oxytetracycline (OTC) of 292 field isolates derived from main rearing areas, different hosts and collected over 5 years were assessed. The results allowed for the determination of epidemiological cut-off values that were used to characterize the pathogen population. This work represents the first large-scale field study addressing the antimicrobial susceptibility of P. salmonis, providing evidence of the existence of resistant types with a high incidence of resistance to quinolones. Remarkably, despite the amounts and frequency of therapies, our results disclosed that the issue of resistance to florfenicol and OTC is still in the onset. PMID:26660665

  4. Significant Differences Characterise the Correlation Coefficients between Biocide and Antibiotic Susceptibility Profiles in Staphylococcus aureus.

    PubMed

    Oggioni, Marco R; Coelho, Joana Rosado; Furi, Leonardo; Knight, Daniel R; Viti, Carlo; Orefici, Graziella; Martinez, Jose-Luis; Freitas, Ana Teresa; Coque, Teresa M; Morrissey, Ian

    2015-01-01

    There is a growing concern by regulatory authorities for the selection of antibiotic resistance caused by the use of biocidal products. We aimed to complete the detailed information on large surveys by investigating the relationship between biocide and antibiotic susceptibility profiles of a large number of Staphylococcus aureus isolates using four biocides and antibiotics commonly used in clinical practice. The minimal inhibitory concentration (MIC) for most clinically-relevant antibiotics was determined according to the standardized methodology for over 1600 clinical S. aureus isolates and compared to susceptibility profiles of benzalkonium chloride, chlorhexidine, triclosan, and sodium hypochlorite. The relationship between antibiotic and biocide susceptibility profiles was evaluated using non-linear correlations. The main outcome evidenced was an absence of any strong or moderate statistically significant correlation when susceptibilities of either triclosan or sodium hypochlorite were compared for any of the tested antibiotics. On the other hand, correlation coefficients for MICs of benzalkonium chloride and chlorhexidine were calculated above 0.4 for susceptibility to quinolones, beta-lactams, and also macrolides. Our data do not support any selective pressure for association between biocides and antibiotics resistance and furthermore do not allow for a defined risk evaluation for some of the compounds. Importantly, our data clearly indicate that there does not involve any risk of selection for antibiotic resistance for the compounds triclosan and sodium hypochlorite. These data hence infer that biocide selection for antibiotic resistance has had so far a less significant impact than feared. PMID:25760337

  5. Significant Differences Characterise the Correlation Coefficients between Biocide and Antibiotic Susceptibility Profiles in Staphylococcus aureus

    PubMed Central

    Oggioni, Marco R; Rosado Coelho, Joana; Furi, Leonardo; Knight, Daniel R; Viti, Carlo; Orefici, Graziella; Martinez, Jose-Luis; Freitas, Ana Teresa; Coque, Teresa M; Morrissey, Ian

    2015-01-01

    There is a growing concern by regulatory authorities for the selection of antibiotic resistance caused by the use of biocidal products. We aimed to complete the detailed information on large surveys by investigating the relationship between biocide and antibiotic susceptibility profiles of a large number of Staphylococcus aureus isolates using four biocides and antibiotics commonly used in clinical practice. The minimal inhibitory concentration (MIC) for most clinically-relevant antibiotics was determined according to the standardized methodology for over 1600 clinical S. aureus isolates and compared to susceptibility profiles of benzalkonium chloride, chlorhexidine, triclosan, and sodium hypochlorite. The relationship between antibiotic and biocide susceptibility profiles was evaluated using non-linear correlations. The main outcome evidenced was an absence of any strong or moderate statistically significant correlation when susceptibilities of either triclosan or sodium hypochlorite were compared for any of the tested antibiotics. On the other hand, correlation coefficients for MICs of benzalkonium chloride and chlorhexidine were calculated above 0.4 for susceptibility to quinolones, beta-lactams, and also macrolides. Our data do not support any selective pressure for association between biocides and antibiotics resistance and furthermore do not allow for a defined risk evaluation for some of the compounds. Importantly, our data clearly indicate that there does not involve any risk of selection for antibiotic resistance for the compounds triclosan and sodium hypochlorite. These data hence infer that biocide selection for antibiotic resistance has had so far a less significant impact than feared. PMID:25760337

  6. Urinary Escherichia coli antimicrobial susceptibility profiles and their relationship with community antibiotic use in Tasmania, Australia.

    PubMed

    Meumann, Ella M; Mitchell, Brett G; McGregor, Alistair; McBryde, Emma; Cooley, Louise

    2015-10-01

    This study assessed urinary Escherichia coli antibiotic susceptibility patterns in Tasmania, Australia, and examined their association with community antibiotic use. The susceptibility profiles of all urinary E. coli isolates collected in Tasmania between January 2010 and December 2012 were included. The amount of Pharmaceutical Benefits Scheme (PBS)-subsidised use of amoxicillin, amoxicillin/clavulanic acid (AMC), cefalexin, norfloxacin, ciprofloxacin and trimethoprim was retrieved (at the Tasmanian population level) and the number of defined daily doses per 1000 population per day in Tasmania for these antibiotics was calculated for each month during the study period. Antimicrobial susceptibility data were assessed for changes over time in the 3-year study period. Antimicrobial use and susceptibility data were assessed for seasonal differences and lag in resistance following antibiotic use. Excluding duplicates, 28145 E. coli isolates were included. Resistance levels were low; 35% of isolates were non-susceptible to amoxicillin, 14% were non-susceptible to trimethoprim and <5% were non-susceptible to AMC, cefalexin, gentamicin and norfloxacin. Amoxicillin use increased by 35% during winter/spring compared with summer/autumn, and AMC use increased by 21%. No seasonal variation in quinolone use or resistance was detected. The low levels of antimicrobial resistance identified may relate to Tasmania's isolated geographical location. Significant seasonal variation in amoxicillin and AMC use is likely to be due to increased use of these antibiotics for treatment of respiratory tract infections in winter. Quinolone use is restricted by the PBS in Australia, which is the likely explanation for the low levels of quinolone use and resistance identified. PMID:26187365

  7. Antibiotic susceptibility profile of Aeromonas spp. isolates from food in Abu Dhabi, United Arab Emirates.

    PubMed

    Awan, Mohammad Bashir; Maqbool, Ahmed; Bari, Abdul; Krovacek, Karel

    2009-01-01

    A total of 57 Aeromonas isolates from food samples such as fresh and frozen chicken, game birds, pasteurized milk, baby food, bakery products, fruit and vegetables, fish, and water from Abu Dahbi, UAE were investigated for antibiotic susceptibility profile. Most strains were resistant to penicillins (ticarcillin, mezlocillin, oxacillin, piperacillin), sulfamethoxazole, trimethoprim and macrolides (erythromycin, vancomycin, clindamycin) but sensitive to tetracycline, chloramphenicol, nitrofurantoin, aminoglycosides (amikacin, gentamicin, tobramycin), cephalosporins (cefuroxime, ceftrioxone, cefazolin, cephalexin, cephalothin, cefoxitin, cefotaxime), quinolone (ciprofloxacin), colistin sulphate and SXT (trimethoprim-sulfamethoxazole). On the other hand, many antibiotics showed excellent inhibitory activity (>75% strains were sensitive to them) against all the strains tested. These include cefuroxime, ceftrioxone, ciprofloxacin, colistin, amikacin, gentamicin, tetracycline, chloramphenicol, nitrofurantoin, cefotaxime and tobramycin. In conclusion, the results show a detailed pattern of sensitivity of the various Aeromonas spp. isolates to a variety of antibiotics and provide useful information in the context of selective isolation and phenotypic identification of the aeromonads from food. PMID:19382665

  8. Antibiotic Susceptibility Profile of Aeromonas Species Isolated from Wastewater Treatment Plant

    PubMed Central

    Igbinosa, Isoken H.; Okoh, Anthony I.

    2012-01-01

    This study assessed the prevalence of antibiotic-resistant Aeromonas species isolated from Alice and Fort Beaufort wastewater treatment plant in the Eastern Cape Province of South Africa. Antibiotic susceptibility was determined using the disc diffusion method, and polymerase chain reaction (PCR) assay was employed for the detection of antibiotics resistance genes. Variable susceptibilities were observed against ciprofloxacin, chloramphenicol, nalidixic acid, gentamicin, minocycline, among others. Aeromonas isolates from both locations were 100% resistant to penicillin, oxacillin, ampicillin, and vancomycin. Higher phenotypic resistance was observed in isolates from Fort Beaufort compared to isolates from Alice. Class A pse1 β-lactamase was detected in 20.8% of the isolates with a lower detection rate of 8.3% for blaTEM gene. Class 1 integron was present in 20.8% of Aeromonas isolates while class 2 integron and TetC gene were not detected in any isolate. The antibiotic resistance phenotypes observed in the isolates and the presence of β-lactamases genes detected in some isolates are of clinical and public health concern as this has consequences for antimicrobial chemotherapy of infections associated with Aeromonas species. This study further supports wastewater as potential reservoirs of antibiotic resistance determinants in the environment. PMID:22927788

  9. Antibiotic susceptibility profile of Aeromonas species isolated from wastewater treatment plant.

    PubMed

    Igbinosa, Isoken H; Okoh, Anthony I

    2012-01-01

    This study assessed the prevalence of antibiotic-resistant Aeromonas species isolated from Alice and Fort Beaufort wastewater treatment plant in the Eastern Cape Province of South Africa. Antibiotic susceptibility was determined using the disc diffusion method, and polymerase chain reaction (PCR) assay was employed for the detection of antibiotics resistance genes. Variable susceptibilities were observed against ciprofloxacin, chloramphenicol, nalidixic acid, gentamicin, minocycline, among others. Aeromonas isolates from both locations were 100% resistant to penicillin, oxacillin, ampicillin, and vancomycin. Higher phenotypic resistance was observed in isolates from Fort Beaufort compared to isolates from Alice. Class A pse1 β-lactamase was detected in 20.8% of the isolates with a lower detection rate of 8.3% for bla(TEM) gene. Class 1 integron was present in 20.8% of Aeromonas isolates while class 2 integron and TetC gene were not detected in any isolate. The antibiotic resistance phenotypes observed in the isolates and the presence of β-lactamases genes detected in some isolates are of clinical and public health concern as this has consequences for antimicrobial chemotherapy of infections associated with Aeromonas species. This study further supports wastewater as potential reservoirs of antibiotic resistance determinants in the environment. PMID:22927788

  10. Plasmid profiles and antibiotic susceptibility patterns of Staphylococcus aureus isolates from Nigeria.

    PubMed

    Olukoya, D K; Asielue, J O; Olasupo, N A; Ikea, J K

    1995-06-01

    In an investigation into the problems of infections due to Staphylococcus aureus in Nigeria, 100 strains were isolated from various hospitals in Lagos. The strains were screened for the presence of plasmids and for susceptibility to antimicrobial agents. Plasmids were extracted by modification of the method of Takahashi and Nagono[1]. The plasmids were diverse in nature. The strains were found to be highly resistant to commonly prescribed antibiotics. PMID:8669391

  11. Bacteriological profile and antibiotic susceptibility patterns of clinical isolates in a tertiary care cancer center

    PubMed Central

    Bhat, Vivek; Gupta, Sudeep; Kelkar, Rohini; Biswas, Sanjay; Khattry, Navin; Moiyadi, Aliasgar; Bhat, Prashant; Ambulkar, Reshma; Chavan, Preeti; Chiplunkar, Shubadha; Kotekar, Amol; Gupta, Tejpal

    2016-01-01

    Introduction: This increased risk of bacterial infections in the cancer patient is further compounded by the rising trends of antibiotic resistance in commonly implicated organisms. In the Indian setting this is particularly true in case of Gram negative bacilli such as Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. Increasing resistance among Gram positive organisms is also a matter of concern. The aim of this study was to document the common organisms isolated from bacterial infections in cancer patients and describe their antibiotic susceptibilities. Methods: We conducted a 6 month study of all isolates from blood, urine, skin/soft tissue and respiratory samples of patients received from medical and surgical oncology units in our hospital. All samples were processed as per standard microbiology laboratory operating procedures. Isolates were identified to species level and susceptibility tests were performed as per Clinical Laboratory Standards Institute (CLSI) guidelines -2012. Results: A total of 285 specimens from medical oncology (114) and surgical oncology services (171) were cultured. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter spp. were most commonly encountered. More than half of the Acinetobacter strains were resistant to carbapenems. Resistance in Klebsiella pneumoniae to cephalosporins, fluoroquinolones and carbapenems was >50%. Of the Staphylococcus aureus isolates 41.67% were methicillin resistant. Conclusion: There is, in general, a high level of antibiotic resistance among gram negative bacilli, particularly E. coli, Klebsiella pneumoniae and Acinetobacter spp. Resistance among Gram positives is not as acute, although the MRSA incidence is increasing. PMID:27051152

  12. Disinfectant and antibiotic susceptibility profiles of Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The disinfectant and antibiotic susceptibility profiles of 344 Escherichia coli O157:H7 isolates from cattle feces, hide, carcass, and ground beef from different areas of the United States were determined. Overall, a low incidence of antibiotic resistance was observed (14%). The highest-incidence ...

  13. Serotypes, Antibiotic Susceptibilities, and Multi-Locus Sequence Type Profiles of Streptococcus agalactiae Isolates Circulating in Beijing, China

    PubMed Central

    Ma, Xiu-hua; Song, Feng-li; Fan, Ling; Guo, Cui-mei; Shi, Wei; Yu, Sang-jie; Yao, Kai-hu; Yang, Yong-hong

    2015-01-01

    Background To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections. Methods All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles. Results In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB. Conclusion S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB. PMID:25781346

  14. Antibiotic Susceptibility Profile of Bacteria Isolated from Natural Sources of Water from Rural Areas of East Sikkim

    PubMed Central

    Poonia, Shubra; Singh, T. Shantikumar; Tsering, Dechen C.

    2014-01-01

    Background: Contamination of water, food, and environment with antibiotic-resistant bacteria poses a serious public health issue. Objective: The objective was to study the bacterial pollution of the natural sources of water in east Sikkim and to determine the antimicrobial profile of the bacterial isolates. Materials and Methods: A total of 225 samples, 75 each during winter, summer, and monsoon season were collected from the same source in every season for bacteriological analysis by membrane filtration method. Antibiotic susceptibility test was performed using standard disc diffusion method. Results: A total of 19 bacterial species of the genera Escherichia, Klebsiella, Proteus, Salmonella, Shigella, Enterobacter, Citrobacter, Morganella, Pseudomonas, Acinetobacter, Flavobacterium, and Serratia were isolated and their antimicrobial sensitivity tested. Generally, most bacterial isolates except Salmonella and Shigella species were found resistant to commonly used antibiotics such as ampicillin (57.5%), trimethoprim/sulfamethoxaole (39.1%), amoxicillin/clavulanic acid (37.4%), cefixime (34.5%), tetracycline (29.1%), ceftazidime (26.3%), ofloxacin (25.9%), amikacin (8.7%), and gentamicin (2.7%) but sensitive to imipenem and piperacillin/tazobactam. Conclusion: Natural sources of water in east Sikkim are grossly contaminated with bacteria including enteropathogens. The consumption of untreated water from these sources might pose health risk to consumers. PMID:25136156

  15. Molecular characterization, serotyping, and antibiotic susceptibility profile of Leptospira interrogans serovar Copenhageni isolates from Brazil.

    PubMed

    Miraglia, Fabiana; Matsuo, Minekazo; Morais, Zenaide Maria; Dellagostin, Odir Antonio; Seixas, Fabiana Kömmling; Freitas, Julio César; Hartskeerl, Rudy; Moreno, Luisa Zanolli; Costa, Bárbara Letícia; Souza, Gisele Oliveira; Vasconcellos, Silvio Arruda; Moreno, Andrea Micke

    2013-11-01

    Leptospira interrogans serogroup Icterohaemorrhagiae is the major serogroup infecting humans worldwide, and rodents and dogs are the most significant transmission sources in urban environments. Knowledge of the prevalent serovars and their maintenance hosts is essential to understand the epidemiology of leptospirosis. In this study, 20 Leptospira isolates were evaluated by pulsed-field gel electrophoresis (PFGE), variable number tandem-repeat analysis (VNTR), serotyping, and determination of antimicrobial resistance profile. Isolates, originated from bovine, canine, human, and rodent sources, were characterized by microscopic agglutination test with polyclonal and monoclonal antibodies and were identified as L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni. MICs of antimicrobials often used in veterinary medicine were determined by broth microdilution test. Most of tested antibiotics were effective against isolates, including penicillin, ampicillin, and ceftiofur. Higher MIC variability was observed for fluoroquinolones and neomycin; all isolates were resistant to trimethoprim/sulfamethoxazole and sulphadimethoxine. Isolates were genotyped by PFGE and VNTR; both techniques were unable to discriminate between serovars Copenhageni and Icterohaemorrhagiae, as expected. PFGE clustered all isolates in 1 pulsotype, indicating that these serovars can be transmitted between species and that bovine, rodent, and dogs can maintain them in the environment endangering the human population. PMID:24054736

  16. Longitudinal Antibiotic Susceptibility Profiles of Staphylococcus aureus Cutaneous Infections in a Pediatric Outpatient Population.

    PubMed

    Slater, Nathaniel A; Gilligan, Peter H; Morrell, Dean S

    2016-09-01

    This longitudinal update on Staphylococcus aureus prevalence and antibiotic resistance patterns surveyd 291 cultures from 188 patients in a pediatric outpatient dermatology clinic with suspected skin and soft tissue infections. The prevalence of methicillin-resistant Staphylococcus aureus remained stable at 24%. Staphylococcus aureus resistance to tetracyclines modestly but demonstrably increased in the interval since 2009. PMID:27384814

  17. Antibiotic susceptibility pattern and analysis of plasmid profiles of Pseudomonas aeruginosa from human, animal and plant sources.

    PubMed

    Odumosu, Bamidele Tolulope; Ajetunmobi, Olabayo; Dada-Adegbola, Hannah; Odutayo, Idowu

    2016-01-01

    Multidrug resistant organisms (MDROs) constitute a major public health threat globally. Clinical isolates of Pseudomonas aeruginosa remains one of the most studied MDROs however there is paucity of information regarding the susceptibility of its animal and plants isolates to antipseudomonas drug in Nigeria. From a total of 252 samples consisting of plants, animals and clinical samples, 54, 24 and 22 P. aeruginosa were isolated from vegetables, animals and clinical sources respectively. All the isolates were identified by standard biochemical methods. Antimicrobial susceptibility testing (AST) of the 100 P. aeruginosa isolates against 7 antipseudomonal drugs was carried out by disk diffusion method, the phenotypic detection of ESBL was done by double disk synergy test (DDST) while plasmid extraction on 20 selected isolates based on their resistance to 2 or more classes of antibiotics was carried out by alkaline lysis method and analysed with Lambda DNA/Hind lll marker respectively. The AST results revealed highest resistance of 91 and 55 % to ceftazidime and carbenicillin respectively while highest susceptibilities of 99 % for piperacillin-tazobactam and imipenem were recorded in overall assay. Fifteen out of 100 isolates specifically (10) from vegetables, (3) clinical and (2) poultry isolates showed synergy towards the beta-lactamase inhibitor indicating production of ESBL by DDST method. Detection of plasmids was among vegetable (n = 4), poultry (n = 4), cow (n = 3) and clinical isolates (n = 1). Plasmid profile for the selected isolates revealed 6 of the strains had one plasmids each while 5 strains possessed 2-4 plasmids and 1 strain had 5 plasmids. The sizes of the plasmid range from <1 to ≥23kbp. Detection of ESBL and Plasmids among the investigated isolates is suggestive of multiple interplay of resistance mechanism among the isolates. Plants and animal isolates of P. aeruginosa harbouring multiple mechanisms of resistance is of concern due to the

  18. Antibiotic and disinfectant susceptibility profiles of vancomycin-resistant Enterococcus faecium (VRE) isolated from community wastewater in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vancomycin-resistant Enterococcus faecium (VRE) previously isolated from human wastewater effluents in a nonclinical semiclosed agri-food system in Texas were characterized for susceptibility to antibiotics and disinfectants. The 50 VRE were resistant to eight fluoroquinolones and to 10 of 17 Natio...

  19. Microbial and Antibiotic Susceptibility Profile among Clinical Samples of Patients with Acute Leukemia

    PubMed Central

    Abdollahi, Alireza; Hakimi, Faezeh; Doomanlou, Mahsa; Azadegan, Azadeh

    2016-01-01

    Introduction: Preventing and starting early treatment of infections in patients whose immunity system is weak due to malignancies like leukemia can reduce mortality. This study aimed to determine microbial and antibiotic resistance patterns in clinical samples of patients with acute leukemia to start early treatment before the results of clinical tests are known. Subjects and Methods: In this cross-sectional study, the clinical samples of all patients hospitalized with the diagnosis of acute leukemia were cultured and their antibiogram was evaluated. Then, the data were analyzed by SPSS 18 based on the objectives of the study. Results: Of a total of 2,366 samples, 18.95% were reported to be positive blood samples, 22.96% were reported to be urine samples and 36% wound samples. E. coli was the most common bacteria isolated from the blood and urine cultures (34% in blood, 32% in urine culture) while Staphylococcus Aureus was the most common in the wound culture (35%). The highest level of sensitivity in the organisms with positive blood culture was to Ciprofloxacin, while in positive urine and wound culture was to Imipenem. The highest resistance in blood, urine and wound culture was to Cotrimoxazole. Conclusion: According to results obtained from this study, it is necessary to conduct appropriate studies on this issue in specific conditions in our country. The findings of this study can be used in clinics for more accurate diagnosis, more effective treatment before the results of clinical tests are known and also for prevention of infection in cancer patients. PMID:27252805

  20. Antibiotic and disinfectant susceptibility profiles of vancomycin-resistant Enterococcus faecium (VRE) isolated from community wastewater in Texas.

    PubMed

    Beier, Ross C; Duke, Sara E; Ziprin, Richard L; Harvey, Roger B; Hume, Michael E; Poole, Toni L; Scott, H Morgan; Highfield, Linda D; Alali, Walid Q; Andrews, Kathleen; Anderson, Robin C; Nisbet, David J

    2008-03-01

    Vancomycin-resistant Enterococcus faecium (VRE) from human wastewater effluents in a nonclinical semiclosed agri-food system in Texas were characterized for susceptibility to antibiotics and disinfectants. The 50 VRE were resistant to eight fluoroquinolones and 10 of 17 antimicrobials typically active against Gram-positive organisms. The VRE were susceptible to quinupristin/dalfopristin and linezolid. Lack of the insertion element IS1251 correlated with VRE susceptibility to streptomycin and gentamicin at p < 0.0001 and p = 0.033, respectively. An association was observed between pulsed-field gel electrophoresis genotypes Ic and II and susceptibility to streptomycin at p = 0.0006. VRE susceptibility for nine disinfectants and five disinfectant components is shown. Ninety-two percent of the isolates had a minimum inhibitory concentration (MIC) for triclosan > or =2 ppm. Triclosan MICs for many of the VRE were well over expected product application levels. No association was observed between antibiotic resistance and disinfectant susceptibility in these VRE. Enterococci multiply-resistant to vancomycin and aminoglycosides were found in a non-hospital environment where one would not expect to find them. PMID:18193143

  1. MICROBIAL PROFILE AND ANTIBIOTIC SUSCEPTIBILITY PATTERNS OF PATHOGENS CAUSING VENTILATOR- ASSOCIATED PNEUMONIA AT INTENSIVE CARE UNIT, SESTRE MILOSRDNICE UNIVERSITY HOSPITAL CENTER, ZAGREB, CROATIA.

    PubMed

    Turković, Tihana Magdić; Grginić, Ana Gverić; Cucujić, Branka Đuras; Gašpar, Božena; Širanović, Mladen; Perić, Mladen

    2015-06-01

    Ventilator-associated pneumonia (VAP) is very common in many intensive care Units, but there are still many uncertainties about VAP, especially about the choice of initial empiric antibiotics. The incidence of specific pathogens with different susceptibility patterns causing VAP varies from hospital to hospital. This is the reason why empiric initial antibiotic treatment for VAP should be based not only on general guidelines (that recommend therapy according to the presence of risk factors for multidrug-resistant bacteria), but also on up-to-date information on local epidemiology. The aim of this study was to determine the microbial profile of pathogens causing VAP and their antibiotic susceptibility patterns. The study was conducted in the 15-bed surgical and neurosurgical Intensive Care Unit, Department of Anesthesiology and Intensive Care, Sestre milosrdnice University Hospital Center, Zagreb, Croatia. Retrospective data were collected from September 2009 to March 2013. All patients that developed VAP during the study period were eligible for the study. According to study results, the incidence of VAP was 29.4%. The most commonly isolated bacterium was Staphylococcus aureus (21.1%), followed by Pseudomonas aeruginosa (19.0%) and Acinetobacter species (13.6%). All Staphylococcus aureus isolates were susceptible to vancomycin and linezolid. Pseudomonas aeruginosa showed 100% susceptibility to cefepime and very high susceptibility to pip'eracillin-tazobactam (96%), ceftazidime (93%) and ciprofloxacin (89%). Ampicillin-sulbactam was highly effective for Acinetobacter species, showing resistance in only 8% of isolates. In conclusion, according to study data, appropriate empiric antibiotic therapy for patients with VAP without risk factors for multidrug-resistant bacteria is ceftriaxone and for patients with risk factors for multidrug-resistant bacteria ampicillin-sulbactam plus cefepime plus vancomycin or linezolid. PMID:26415308

  2. Bacteriological Profile and Antibiotic Susceptibility Pattern of Neonatal Sepsis at a Teaching Hospital in Bayelsa State, Nigeria

    PubMed Central

    Peterside, Oliemen; Pondei, Kemebradikumo; Akinbami, Felix O

    2015-01-01

    Background: Sepsis is one of the most common causes of neonatal hospital admissions and is estimated to cause 26% of all neonatal deaths worldwide. While waiting for results of blood culture, it is necessary to initiate an empirical choice of antibiotics based on the epidemiology of causative agents and antibiotic sensitivity pattern in a locality. Objective: To determine the major causative organisms of neonatal sepsis at the Niger Delta University Teaching Hospital (NDUTH), as well as their antibiotic sensitivity patterns, with the aim of formulating treatment protocols for neonates. Methods: Within a 27-month period (1st of October 2011 to the 31st of December 2013), results of blood culture for all neonates screened for sepsis at the Special Care Baby Unit of the hospital were retrospectively studied. Results: Two hundred and thirty-three (49.6%) of the 450 neonates admitted were screened for sepsis. Ninety-seven (43.5%) of them were blood culture positive, with 52 (53.6%) of the isolated organisms being Gram positive and 45 (46.4%) Gram negative. The most frequently isolated organism was Staphylococcus aureus (51.5%) followed by Escherichia coli (16.5%) and Klebsiella pneumoniae (14.4%). All isolated organisms demonstrated the highest sensitivity to the quinolones. Conclusion: Neonatal sepsis is a significant cause of morbidity among neonates admitted at the NDUTH. There is a need for regular periodic surveillance of the causative organisms of neonatal sepsis as well as their antibiotic susceptibility pattern to inform the empirical choice of antibiotic prescription while awaiting blood culture results. PMID:26543394

  3. Optimization of an antibiotic sensitivity assay for Mycoplasma hyosynoviae and susceptibility profiles of field isolates from 1997 to 2011.

    PubMed

    Schultz, K K; Strait, E L; Erickson, B Z; Levy, N

    2012-07-01

    Mycoplasma hyosynoviae is a common agent responsible for polyarthritis leading to decreased production in swine herds worldwide. Antimicrobial agents are used to combat infections; however breakpoints for M. hyosynoviae have not yet been established. A number of methods have previously been utilized to analyze minimum inhibitory concentrations (MICs) for antibiotics against M. hyosynoviae; however these techniques as currently described are not easily standardized between laboratories. A dry microbroth dilution method was conducted to compare the minimum inhibitory concentrations (MICs) for 18 antibiotics, representative of different classes, against 24 recent isolates (23 field isolates and the type strain) of M. hyosynoviae. The MICs were determined using standard, commercially available 96-well Sensititre(®) plates containing various freeze-dried antibiotics at a range of concentrations appropriate to their potency. Clindamycin (CLI), a lincosamide antibiotic, showed the highest activity and most consistent inhibition for all isolates with an MIC(50) of ≤ 0.12 μg/ml. Tiamulin (TIA), a pleuromutilin derivative, exhibited an MIC(50) of ≤ 0.25 μg/ml. The isolates had similar levels of susceptibility to the quinolones, enrofloxacin (ENRO) and danofloxacin (DANO), exhibiting an MIC(50) of 0.25 μg/ml and 0.5 μg/ml, respectively. For the macrolides, the MIC(50) for tylosin (TYLT) and tilmicosin (TIL) was ≤ 0.25 μg/ml and ≤ 2 μg/ml respectively, but was ≤ 16 μg/ml for tulathromycin (TUL). For the aminoglycosides, the MIC(50) for gentamicin (GEN) was ≤ 0.5 μg/ml, while spectinomycin (SPE) and neomycin (NEO) had an MIC(50) of ≤ 4 μg/ml. The tetracyclines, oxytetracycline (OXY) and chlortetracycline (CTET) both had an MIC(50) of ≤ 2 μg/ml. Florfenicol (FFN) exhibited a MIC(50) of ≤ 1 μg/ml. All isolates were resistant to penicillin (PEN), ampicillin (AMP), ceftiofur (TIO), trimethoprim/sulfamethoxazole (SXT), and sulphadimethoxine (SDM) at all

  4. Comparative study on the antibiotic susceptibility and plasmid profiles of Vibrio alginolyticus strains isolated from four Tunisian marine biotopes.

    PubMed

    Lajnef, Rim; Snoussi, Mejdi; Romalde, Jesús López; Nozha, Cohen; Hassen, Abdennaceur

    2012-12-01

    The antibiotic resistance patterns and the plasmids profiles of the predominant etiological agent responsible for vibriosis in Tunisia, V. alginolyticus were studied to contribute to control their spread in some Mediterranean aquaculture farms and seawater. The sixty-nine V. alginolyticus strains isolated from different marine Tunisian biotopes (bathing waters, aquaculture and conchylicole farms and a river connected to the seawater during the cold seasons) were multi-drug resistant with high resistance rate to ampicillin, kanamycin, doxycyclin, erythromycin, imipinem, and nalidixic acid. The multiple resistance index ranged from 0.3 to 0.7 for the isolates of Khenis, from 0.5 to 0.8 for those of Menzel Jmil, from 0.5 to 0.75 (Hergla) and from 0.3 to 0.7 for the isolates of Oued Soltane. The high value of antibiotic resistance index was recorded for the V. alginolyticus population isolated from the fish farm in Hergla (ARI = 0.672) followed by the population isolated from the conchylicole station of Menzel Jmil (ARI = 0.645). The results obtained by the MIC tests confirmed the resistance of the V. alginolyticus to ampicillin, erythromycin, kanamycin, cefotaxime, streptomycin and trimethoprim. Plasmids were found in 79.48 % of the strains analyzed and 30 different plasmid profiles were observed. The strains had a high difference in the size of plasmids varying between 0.5 and 45 kb. Our study reveals that the antibiotic-resistant bacteria are widespread in the aquaculture and conchylicole farm relatively to others strains isolated from seawater. PMID:22918722

  5. Prevalence, Haemolytic and Haemagglutination Activities and Antibiotic Susceptibility Profiles of Campylobacter spp. Isolated from Human Diarrhoeal Stools in Vhembe District, South Africa

    PubMed Central

    Samie, A.; Ramalivhana, J.; Igumbor, E.O.; Obi, C.L.

    2007-01-01

    Campylobacter species are increasingly being recognized as agents of gastroenteritis worldwide. However, data on the pathogenic characteristics of the organism isolated in rural communities in South Africa are lacking. In this study, the prevalence of Campylobacter spp. from diarrhoeal stools, haemolytic and haemagglutinating activities of the isolates, and antibiotic susceptibility profiles, including minimum inhibitory concentration (MIC) patterns to different antibiotics, were determined using the standard microbiological techniques. Campylobacter spp. were isolated from individuals of all age-groups; however, the infection rate was higher among individuals aged less than two years (30.4%). Of 115 Campylobacter strains isolated, polymerase chain reaction (PCR) analysis indicated that 98 (85%) were C. jejuni, while 17 (15%) were C. coli. Seventy-one (62%) of the strains showed haemolysis on human blood, and 80% agglutinated human blood, whereas 22.6% were β-lactamase-positive. Resistance to antimicrobials, such as erythromycin, ciprofloxacin, vancomycin, and fusidic acid, was high. Increased resistance to macrolide and quinolone antibiotics poses major risks for treatment failure. Haemolytic and haemagglutinating activities may be useful in preliminary characterization of pathogenic strains in settings where Campylobacter-associated infections are common. PMID:18402183

  6. Bacterial nanoscale cultures for phenotypic multiplexed antibiotic susceptibility testing.

    PubMed

    Weibull, Emilie; Antypas, Haris; Kjäll, Peter; Brauner, Annelie; Andersson-Svahn, Helene; Richter-Dahlfors, Agneta

    2014-09-01

    An optimal antimicrobial drug regimen is the key to successful clinical outcomes of bacterial infections. To direct the choice of antibiotic, access to fast and precise antibiotic susceptibility profiling of the infecting bacteria is critical. We have developed a high-throughput nanowell antibiotic susceptibility testing (AST) device for direct, multiplexed analysis. By processing in real time the optical recordings of nanoscale cultures of reference and clinical uropathogenic Escherichia coli strains with a mathematical algorithm, the time point when growth shifts from lag phase to early logarithmic phase (Tlag) was identified for each of the several hundreds of cultures tested. Based on Tlag, the MIC could be defined within 4 h. Heatmap presentation of data from this high-throughput analysis allowed multiple resistance patterns to be differentiated at a glance. With a possibility to enhance multiplexing capacity, this device serves as a high-throughput diagnostic tool that rapidly aids clinicians in prescribing the optimal antibiotic therapy. PMID:24989602

  7. Fast measurement of bacterial susceptibility to antibiotics

    NASA Technical Reports Server (NTRS)

    Chappelle, E. W.; Picciolo, G. L.; Schrock, C. G.

    1977-01-01

    Method, based on photoanalysis of adenosine triphosphate using light-emitting reaction with luciferase-luciferin technique, saves time by eliminating isolation period required by conventional methods. Technique is also used to determine presence of infection as well as susceptibilities to several antibiotics.

  8. Polyamine Effects on Antibiotic Susceptibility in Bacteria▿

    PubMed Central

    Kwon, Dong-Hyeon; Lu, Chung-Dar

    2007-01-01

    Biogenic polyamines (e.g., spermidine and spermine) are a group of essential polycationic compounds found in all living cells. The effects of spermine and spermidine on antibiotic susceptibility were examined with gram-negative Escherichia coli and Salmonella enterica serovar Typhimurium bacteria and clinical isolates of Pseudomonas aeruginosa and with gram-positive Staphylococcus aureus bacteria, including methicillin-resistant S. aureus (MRSA). Exogenous spermine exerted a dose-dependent inhibition effect on the growth of E. coli, S. enterica serovar Typhimurium, and S. aureus but not P. aeruginosa, as depicted by MIC and growth curve measurements. While the MICs of polymyxin and ciprofloxacin were in general increased by exogenous spermine and spermidine in P. aeruginosa, this adverse effect was not observed in enteric bacteria and S. aureus. It was found that spermine and spermidine can decrease the MICs of β-lactam antibiotics in all strains as well as other types of antibiotics in a strain-dependent manner. Significantly, the MICs of oxacillin for MRSA Mu50 and N315 were decreased more than 200-fold in the presence of spermine, and this effect of spermine was retained when assessed in the presence of divalent ions (magnesium or calcium; 3 mM) or sodium chloride (150 mM). The effect of spermine on the sensitization of P. aeruginosa and MRSA to antibiotics was further demonstrated by population analysis and time-killing assays. The results of checkerboard assays with E. coli and S. aureus indicated a strong synergistic effect of spermine in combination with β-lactams and chloramphenicol. The decreased MICs of β-lactams implied that the possible blockage of outer membrane porins by exogenous spermine or spermidine did not play a crucial role in most cases. In contrast, only the MIC of imipenem against P. aeruginosa was increased by exogenous spermine and spermidine, and this resistance effect was abolished in a mutant strain devoid of the outer membrane porin

  9. Comparison of antibiotic resistance, virulence gene profiles, and pathogenicity of methicillin-resistant and methicillin-susceptible Staphylococcus aureus using a Caenorhabditis elegans infection model

    PubMed Central

    Thompson, Terissa; Brown, Paul D

    2014-01-01

    Objectives: This study compared the presence of 35 virulence genes, resistance phenotypes to 11 anti-staphylococcal antibiotics, and pathogenicity in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). Methods: Multiplex PCR analysis was used to differentiate Staphylococcus aureus isolates (n = 102) based on characterization of the Staphylococcal Cassette Chromosome mec (SCCmec). Singleplex and multiplex PCR assays targeting 35 virulence determinants were used to analyze the virulence repertoire of S. aureus. In vitro activities of the antibiotics were determined by the disk-diffusion method. The pathogenicity of representative isolates was assessed using Caenorhabditis elegans survival assays. Significance in virulence distribution and antibiotic resistance phenotypes was assessed using the Chi-squared tests. Kaplan–Meier survival estimates were used to analyze nematode survival and significance of survival rates evaluated using the log-rank test. Results: Except for sei (staphylococcal enterotoxin I) (P  =  0.027), all other virulence genes were not significantly associated with MRSA. Resistance to clindamycin (P  =  0.03), tetracycline (P  =  0.048), trimethoprim/sulfamethoxazole (P  =  0.038), and oxacillin (P  =  0.004) was significantly associated with MRSA. Survival assay showed MSSA having a lower median lifespan of 3 days than MRSA that had a median lifespan of 6 days. The difference in the killing time of MRSA and MSSA was significant (P < 0.001). Conclusion: While antibiotic resistance was significantly associated with MRSA, there was no preferential distribution of the virulence genes. The quicker killing potential of MSSA compared to MRSA suggests that carriage of virulence determinants per se does not determine pathogenicity in S. aureus. Pathogenicity is impacted by other factors, possibly antibiotic resistance. PMID:25319852

  10. HT-SPOTi: A Rapid Drug Susceptibility Test (DST) to Evaluate Antibiotic Resistance Profiles and Novel Chemicals for Anti-Infective Drug Discovery.

    PubMed

    Danquah, Cynthia A; Maitra, Arundhati; Gibbons, Simon; Faull, Jane; Bhakta, Sanjib

    2016-01-01

    Antibiotic resistance is one of the major threats to global health and well-being. The past decade has seen an alarming rise in the evolution and spread of drug-resistant strains of pathogenic microbes. The emergence of extensively drug resistant (XDR) strains of Mycobacterium tuberculosis and antimicrobial resistance among the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter species) as well as fungal pathogens (such as certain species of Candida, Aspergillus, Cryptococcus, and Trichophyton) poses a significant 21st century scientific challenge. With an extremely limited arsenal of efficacious antibiotics, techniques that can (a) identify novel antimicrobials and (b) detect antimicrobial resistance are becoming increasingly important. In this article, we illustrate the HT-SPOTi, an assay that is principally based on the growth of an organism on agar medium containing a range of different concentrations of drugs or inhibitors. The simple methodology makes this assay ideal for evaluating novel antimicrobial compounds as well as profiling an organism's antibiotic resistance profile. PMID:26855282

  11. Antibiotic sensitivity profiles determined with an Escherichia coli gene knockout collection: generating an antibiotic bar code.

    PubMed

    Liu, Anne; Tran, Lillian; Becket, Elinne; Lee, Kim; Chinn, Laney; Park, Eunice; Tran, Katherine; Miller, Jeffrey H

    2010-04-01

    We have defined a sensitivity profile for 22 antibiotics by extending previous work testing the entire KEIO collection of close to 4,000 single-gene knockouts in Escherichia coli for increased susceptibility to 1 of 14 different antibiotics (ciprofloxacin, rifampin [rifampicin], vancomycin, ampicillin, sulfamethoxazole, gentamicin, metronidazole, streptomycin, fusidic acid, tetracycline, chloramphenicol, nitrofurantoin, erythromycin, and triclosan). We screened one or more subinhibitory concentrations of each antibiotic, generating more than 80,000 data points and allowing a reduction of the entire collection to a set of 283 strains that display significantly increased sensitivity to at least one of the antibiotics. We used this reduced set of strains to determine a profile for eight additional antibiotics (spectinomycin, cephradine, aztreonem, colistin, neomycin, enoxacin, tobramycin, and cefoxitin). The profiles for the 22 antibiotics represent a growing catalog of sensitivity fingerprints that can be separated into two components, multidrug-resistant mutants and those mutants that confer relatively specific sensitivity to the antibiotic or type of antibiotic tested. The latter group can be represented by a set of 20 to 60 strains that can be used for the rapid typing of antibiotics by generating a virtual bar code readout of the specific sensitivities. Taken together, these data reveal the complexity of intrinsic resistance and provide additional targets for the design of codrugs (or combinations of drugs) that potentiate existing antibiotics. PMID:20065048

  12. Characterization of Renibacterium salmoninarum with reduced susceptibility to macrolide antibiotics by a standardized antibiotic susceptibility test.

    PubMed

    Rhodes, Linda D; Nguyen, Oanh T; Deinhard, Rebecca K; White, Teresa M; Harrell, Lee W; Roberts, Marilyn C

    2008-08-01

    Three cohorts of juvenile and subadult Chinook salmon Oncorhynchus tshawytscha received multiple treatments with macrolide antibiotics for bacterial kidney disease (BKD) during rearing in a captive broodstock program. A total of 77 mortalities among the cohorts were screened for Renibacterium salmoninarum, the etiologic agent of BKD, by agar culture from kidney, and isolates from 7 fish were suitable for growth testing in the presence of macrolide antibiotics. The minimum inhibitory concentration (MIC) of erythromycin and azithromycin was determined by a modification of the standardized broth assay using defined medium. The American Type Culture Collection (ATCC) type strain 33209 exhibited a MIC of 0.008 microg m(-1) to either erythromycin or azithromycin. Isolates from 3 fish displayed MICs identical to the MICs for the ATCC type strain 33209. In contrast, isolates from 4 fish exhibited higher MICs, ranging between 0.125 and 0.250 microg ml(-1) for erythromycin and between 0.016 and 0.031 microg ml(-1) for azithromycin. Sequence analysis of the mutational hotspots for macrolide resistance in the 23S rDNA gene and the open reading frames of ribosomal proteins L4 and L22 found identical sequences among all isolates, indicating that the phenotype was not due to mutations associated with the drug-binding site of 23S rRNA. These results are the first report of R. salmoninarum with reduced susceptibility to macrolide antibiotics isolated from fish receiving multiple antibiotic treatments. PMID:18814542

  13. Microbial content and antibiotic susceptibility of bacterial isolates from yoghurts.

    PubMed

    Kyriacou, Adamantini; Tsimpidi, Eirini; Kazantzi, Evagelia; Mitsou, Eudokia; Kirtzalidou, Ekaterini; Oikonomou, Yannis; Gazis, George; Kotsou, Maria

    2008-09-01

    A total of 83 dairy products form the Greek market were examined for their bacterial populations and results were compared with the label information. The antibiotic susceptibility of the bacterial isolates was also examined. The status labeling of the yoghurts and the dairy desserts was found insufficient. The 89.8% of the cocci was found susceptible against all the 12 antibiotics examined. Lactobacillus spp. strains exhibited some kind of resistance to one or more antibiotics. The isolates of Lactobacillus delbrueckii showed resistance to one to four antibiotics, the isolates of Lactobacillus acidophilus were resistant to one to three antibiotics, while the Lactobacillus paracasei strains were resistant to four or five antibiotics. Finally, multi-resistant strains (six to nine antibiotics) were found only among the Lactobacillus rhamnosus strains. PMID:18686111

  14. Susceptibility to antibiotics and biochemical properties of Desulfovibrio desulfuricans strains.

    PubMed

    Dzierzewicz, Z; Cwalina, B; Jaworska-Kik, M; Weglarz, L; Wilczok, T

    2001-01-01

    Susceptibility to several antibiotics and biochemical properties of intestinal and soil strains of Desulfovibrio desulfuricans bacteria were investigated using the tests: ATB ANA, Sceptor Anaerobic MIC/ID and API ZYM. It was demonstrated that the D. desulfuricans strains were resistant to penicillin, cefoxitin, clindamycin, metronidazole, erythromycin, rifampicin and teicoplanin. The strains initially susceptible to imipenem became resistant to this drug following 72 h incubation with it. Of 25 analyzed antibiotics there was none that after 72 h action on the bacteria was effective in relation to all of the investigated strains. The differences in susceptibility of D. desulfuricans strains to antibiotics were not associated with the strains' biochemical properties. PMID:12197616

  15. Assessing the antibiotic susceptibility of freshwater Cyanobacteria spp.

    PubMed Central

    Dias, Elsa; Oliveira, Micaela; Jones-Dias, Daniela; Vasconcelos, Vitor; Ferreira, Eugénia; Manageiro, Vera; Caniça, Manuela

    2015-01-01

    Freshwater is a vehicle for the emergence and dissemination of antibiotic resistance. Cyanobacteria are ubiquitous in freshwater, where they are exposed to antibiotics and resistant organisms, but their role on water resistome was never evaluated. Data concerning the effects of antibiotics on cyanobacteria, obtained by distinct methodologies, is often contradictory. This emphasizes the importance of developing procedures to understand the trends of antibiotic susceptibility in cyanobacteria. In this study we aimed to evaluate the susceptibility of four cyanobacterial isolates from different genera (Microcystis aeruginosa, Aphanizomenon gracile, Chrisosporum bergii, Planktothix agradhii), and among them nine isolates from the same specie (M. aeruginosa) to distinct antibiotics (amoxicillin, ceftazidime, ceftriaxone, kanamycine, gentamicine, tetracycline, trimethoprim, nalidixic acid, norfloxacin). We used a method adapted from the bacteria standard broth microdilution. Cyanobacteria were exposed to serial dilution of each antibiotic (0.0015–1.6 mg/L) in Z8 medium (20 ± 1°C; 14/10 h L/D cycle; light intensity 16 ± 4 μEm−2s−1). Cell growth was followed overtime (OD450nm/microscopic examination) and the minimum inhibitory concentrations (MICs) were calculated for each antibiotic/isolate. We found that β-lactams exhibited the lower MICs, aminoglycosides, tetracycline and norfloxacine presented intermediate MICs; none of the isolates were susceptible to trimethoprim and nalidixic acid. The reduced susceptibility of all tested cyanobacteria to some antibiotics suggests that they might be naturally non-susceptible to these compounds, or that they might became non-susceptible due to antibiotic contamination pressure, or to the transfer of genes from resistant bacteria present in the environment. PMID:26322027

  16. Phenotypic characteristics of coagulase-negative staphylococci: typing and antibiotic susceptibility.

    PubMed

    Jarløv, J O

    1999-01-01

    The present thesis deals with various aspects of handling coagulase-negative staphylococci (CoNS) in the local clinical microbiology laboratory. CoNS are normal inhabitants of the skin and mucus membranes and are increasingly being recognised as opportunistic pathogens causing infection in the immunocompromised host, in particular patients with indwelling plastic devices. In particular the finding of CoNS in specimens which should normally be sterile, such as blood cultures, is of interest. The isolation of the same strain of an opportunistic pathogen, such as CoNS, enhance the likelihood of the bacteria causing infection. Multiple antibiotic resistance, in particular methicillin resistance, is frequent among CoNS hospital-strains on a global scale. beta-lactam antibiotics are the most valuable antibiotics for the treatment of infection with susceptible CoNS. A reliable method for the detection of methicillin resistance, and hereby resistance to all beta-lactam antibiotics, is therefore important. A simple identification method, Minibact-S, has been developed. Minibact-S can identify the CoNS species, which are the most frequently occurring in human specimens. Furthermore, Minibact-S can subtype Staphylococcus epidermidis. Another phenotypic typing method, lectin typing, has been developed for typing S. epidermidis. Lectin typing involves the binding of various biotinylated lectins to the surface of whole immobilised cells of CoNS. Lectins are proteins or glycoproteins which bind specifically to various glycans. When the lectins: Wheat Germ Agglutinin (WGA), Soy Bean Agglutinin (SBA), Concanavalin A (ConA), and Lens Culinaris Agglutinin (LCA) were included, typing of S. epidermidis gave a discriminatory power of the same magnitude as found for DNA-plasmid profile analysis. Lectin typing could be used as a supplementary typing method for S. epidermidis in the local clinical microbiology laboratory, since the method is simple, reproducible and does not require

  17. Antibiotic Sensitivity Profiles Determined with an Escherichia coli Gene Knockout Collection: Generating an Antibiotic Bar Code ▿ †

    PubMed Central

    Liu, Anne; Tran, Lillian; Becket, Elinne; Lee, Kim; Chinn, Laney; Park, Eunice; Tran, Katherine; Miller, Jeffrey H.

    2010-01-01

    We have defined a sensitivity profile for 22 antibiotics by extending previous work testing the entire KEIO collection of close to 4,000 single-gene knockouts in Escherichia coli for increased susceptibility to 1 of 14 different antibiotics (ciprofloxacin, rifampin [rifampicin], vancomycin, ampicillin, sulfamethoxazole, gentamicin, metronidazole, streptomycin, fusidic acid, tetracycline, chloramphenicol, nitrofurantoin, erythromycin, and triclosan). We screened one or more subinhibitory concentrations of each antibiotic, generating more than 80,000 data points and allowing a reduction of the entire collection to a set of 283 strains that display significantly increased sensitivity to at least one of the antibiotics. We used this reduced set of strains to determine a profile for eight additional antibiotics (spectinomycin, cephradine, aztreonem, colistin, neomycin, enoxacin, tobramycin, and cefoxitin). The profiles for the 22 antibiotics represent a growing catalog of sensitivity fingerprints that can be separated into two components, multidrug-resistant mutants and those mutants that confer relatively specific sensitivity to the antibiotic or type of antibiotic tested. The latter group can be represented by a set of 20 to 60 strains that can be used for the rapid typing of antibiotics by generating a virtual bar code readout of the specific sensitivities. Taken together, these data reveal the complexity of intrinsic resistance and provide additional targets for the design of codrugs (or combinations of drugs) that potentiate existing antibiotics. PMID:20065048

  18. Antibiotic Susceptibility Profiles of Dairy Leuconostoc, Analysis of the Genetic Basis of Atypical Resistances and Transfer of Genes In Vitro and in a Food Matrix

    PubMed Central

    Delgado, Susana; Alegría, Ángel; Salvetti, Elisa; Felis, Giovanna E.; Mayo, Baltasar; Torriani, Sandra

    2016-01-01

    In spite of a global concern on the transfer of antibiotic resistances (AR) via the food chain, limited information exists on this issue in species of Leuconostoc and Weissella, adjunct cultures used as aroma producers in fermented foods. In this work, the minimum inhibitory concentration was determined for 16 antibiotics in 34 strains of dairy origin, belonging to Leuconostoc mesenteroides (18), Leuconostoc citreum (11), Leuconostoc lactis (2), Weissella hellenica (2), and Leuconostoc carnosum (1). Atypical resistances were found for kanamycin (17 strains), tetracycline and chloramphenicol (two strains each), and erythromycin, clindamycin, virginiamycin, ciprofloxacin, and rifampicin (one strain each). Surprisingly, L. mesenteroides subsp. mesenteroides LbE16, showed resistance to four antibiotics, kanamycin, streptomycin, tetracycline and virginiamycin. PCR analysis identified tet(S) as responsible for tetracycline resistance in LbE16, but no gene was detected in a second tetracycline-resistant strain, L. mesenteroides subsp. cremoris LbT16. In Leuconostoc mesenteroides subsp. dextranicum LbE15, erythromycin and clindamycin resistant, an erm(B) gene was amplified. Hybridization experiments proved erm(B) and tet(S) to be associated to a plasmid of ≈35 kbp and to the chromosome of LbE15 and LbE16, respectively. The complete genome sequence of LbE15 and LbE16 was used to get further insights on the makeup and genetic organization of AR genes. Genome analysis confirmed the presence and location of erm(B) and tet(S), but genes providing tetracycline resistance in LbT16 were again not identified. In the genome of the multi-resistant strain LbE16, genes that might be involved in aminoglycoside (aadE, aphA-3, sat4) and virginiamycin [vat(E)] resistance were further found. The erm(B) gene but not tet(S) was transferred from Leuconostoc to Enterococcus faecalis both under laboratory conditions and in cheese. This study contributes to the characterization of AR in the

  19. Antibiotic Susceptibility Profiles of Dairy Leuconostoc, Analysis of the Genetic Basis of Atypical Resistances and Transfer of Genes In Vitro and in a Food Matrix.

    PubMed

    Flórez, Ana Belén; Campedelli, Ilenia; Delgado, Susana; Alegría, Ángel; Salvetti, Elisa; Felis, Giovanna E; Mayo, Baltasar; Torriani, Sandra

    2016-01-01

    In spite of a global concern on the transfer of antibiotic resistances (AR) via the food chain, limited information exists on this issue in species of Leuconostoc and Weissella, adjunct cultures used as aroma producers in fermented foods. In this work, the minimum inhibitory concentration was determined for 16 antibiotics in 34 strains of dairy origin, belonging to Leuconostoc mesenteroides (18), Leuconostoc citreum (11), Leuconostoc lactis (2), Weissella hellenica (2), and Leuconostoc carnosum (1). Atypical resistances were found for kanamycin (17 strains), tetracycline and chloramphenicol (two strains each), and erythromycin, clindamycin, virginiamycin, ciprofloxacin, and rifampicin (one strain each). Surprisingly, L. mesenteroides subsp. mesenteroides LbE16, showed resistance to four antibiotics, kanamycin, streptomycin, tetracycline and virginiamycin. PCR analysis identified tet(S) as responsible for tetracycline resistance in LbE16, but no gene was detected in a second tetracycline-resistant strain, L. mesenteroides subsp. cremoris LbT16. In Leuconostoc mesenteroides subsp. dextranicum LbE15, erythromycin and clindamycin resistant, an erm(B) gene was amplified. Hybridization experiments proved erm(B) and tet(S) to be associated to a plasmid of ≈35 kbp and to the chromosome of LbE15 and LbE16, respectively. The complete genome sequence of LbE15 and LbE16 was used to get further insights on the makeup and genetic organization of AR genes. Genome analysis confirmed the presence and location of erm(B) and tet(S), but genes providing tetracycline resistance in LbT16 were again not identified. In the genome of the multi-resistant strain LbE16, genes that might be involved in aminoglycoside (aadE, aphA-3, sat4) and virginiamycin [vat(E)] resistance were further found. The erm(B) gene but not tet(S) was transferred from Leuconostoc to Enterococcus faecalis both under laboratory conditions and in cheese. This study contributes to the characterization of AR in the

  20. In Vitro Antibiotic Susceptibility of Neisseria gonorrhoeae in Jakarta, Indonesia

    PubMed Central

    Lesmana, Murad; Lebron, Carlos I.; Taslim, Djufri; Tjaniadi, Periska; Subekti, Decy; Wasfy, Momtaz O.; Campbell, James R.; Oyofo, Buhari A.

    2001-01-01

    Antibiotic susceptibilities were determined for 122 Neisseria gonorrheae isolates obtained from 400 sex workers in Jakarta, Indonesia, and susceptibilities to ciprofloxacin, cefuroxime, cefoxitin, cefotaxime, ceftriaxone, chloramphenicol, and spectinomycin were found. All isolates were resistant to tetracycline. A number of the isolates demonstrated decreased susceptibilities to erythromycin (MIC ≥ 1.0 μg/ml), thiamphenicol (MIC ≥ 1.0 μg/ml), kanamycin (MIC ≥ 16.0 μg/ml), penicillin (MIC ≥ 2.0 μg/ml), gentamicin (MIC ≥ 16.0 μg/ml), and norfloxacin (MIC = 0.5 μg/ml). These data showed that certain antibiotics previously used in the treatment of gonorrhea are no longer effective. PMID:11120999

  1. History and epidemiology of antibiotic susceptibilities of Neisseria gonorrhoeae.

    PubMed

    Shigemura, Katsumi; Fujisawa, Masato

    2015-01-01

    Neisseria gonorrhoeae is a common causative microorganism of male urethritis. The most important problem with this infectious disease is antibiotic resistance. For instance, in the 1980's-1990's, most studies showed almost 100% susceptibility of N. gonorrhoeae to the representative cephalosporins, cefixime and cefpodoxime. By the late 1990s, the reported susceptibility decreased to 93.3-100% and further decreased to 82.9-100% in the early 2000's. However, reported susceptibility was revived to 95.8-100% in the late 2000's to 2010's. The susceptibility of N. gonorrhoeae to penicillins varied in different countries and regions. A 2002 Japanese study showed a resistance ratio of about 30% and while Laos, China and Korea showed 80-100% resistance. Fluoroquinolones have shown a dramatic change in their effect on N. gonorrhoeae. In the early 1990's, 0.3-1.3% of N. gonorrhoeae showed low susceptibility or resistance to ciprofloxacin in the US but this figure jumped to 9.5% by 1999. In Asia, N. gonorrhoeae ciprofloxacin resistance or lower susceptibility was about 80-90% in the early 2000's and this trend continues to the present day. Azithromycin is currently the possible last weapon for N. gonorrhoeae treatment per oral administration. The susceptibility of N. gonorrhoeae to azithromycin was 100% in Indonesia in 2004 and the latest study from Germany showed 6% resistance in strains from 2010-2011. This review summarizes the history and epidemiology of N. gonorrhoeae antibiotic susceptibilities, for which the most frequently used antibiotics vary between countries or regions. PMID:25410409

  2. Antibiotic susceptibilities of Serratia marcescens and Enterobacter liquefaciens.

    PubMed

    Greenup, P; Blazevic, D J

    1971-09-01

    Production of 5'-nucleotides by Serratia marcescens and Enterobacter liquefaciens correlates with deoxyribonuclease production, indicating the close relationship between these two organisms. To determine further relationships, susceptibilities of 279 strains of the tribe Klebsielleae were determined by the high-potency disc method, agar-dilution method, or both, by using 14 antibiotics. Ninety-seven per cent of S. marcescens (201 of 207 strains) and 100% of E. liquefaciens (17 strains) had minimum inhibitory concentration (MIC) of 100 mug/ml or greater with colistin and polymyxin B. With these two antibiotics, 93% of other Enterobacter species (28 strains) had MIC values of less than 1.6 mug/ml, and 100% of Klebsiella (27 strains) had MIC values less than 1.6 mug/ml. Consistent patterns were not noted with the other antibiotics tested, but the results with colistin and polymyxin B provide additional evidence of the close relationship of S. marcescens and E. liquefaciens. PMID:4330312

  3. Evaluation of a Rapid Bauer-Kirby Antibiotic Susceptibility Determination

    PubMed Central

    Liberman, Daniel F.; Robertson, Richard G.

    1975-01-01

    To reduce the incubation time requirement in the Bauer-Kirby antibiotic susceptibility test, comparisons were made of the test results at 18 to 20 h (standard) and 7 to 8 h (rapid) utilizing 100 recent clinical isolates. The zone diameters for 664 disks were monitored by using the standard classification: resistant, intermediate, or susceptible. The susceptibility determination was unchanged in 558 out of 664 instances (84.0%). An analysis of the remaining 106 sets revealed that an initial interpretation of intermediate in zone size, subsequently determined resistant or susceptible, accounted for 49 of the observed differences. The reverse changes, initial resistant or susceptible subsequently classified as intermediate, accounted for 20 of the changes. In five instances the interpretation changed from susceptible to resistant; in two cases the interpretation changed from resistant to susceptible. The remaining 30 determinations were classified as indeterminant due to (i) insufficient growth at the early (7 to 8 h) determination, and to (ii) zones which were so large that they could not be measured accurately. The data indicate that zone sizes when measured to the nearest 0.1 mm can be interpreted with reasonable accuracy and the results can be available 10 to 14 h sooner. PMID:1137377

  4. Sensitivity of antibiotic resistant and antibiotic susceptible Escherichia coli, Enterococcus and Staphylococcus strains against ozone.

    PubMed

    Heß, Stefanie; Gallert, Claudia

    2015-12-01

    Tolerance of antibiotic susceptible and antibiotic resistant Escherichia coli, Enterococcus and Staphylococcus strains from clinical and wastewater samples against ozone was tested to investigate if ozone, a strong oxidant applied for advanced wastewater treatment, will affect the release of antibiotic resistant bacteria into the aquatic environment. For this purpose, the resistance pattern against antibiotics of the mentioned isolates and their survival after exposure to 4 mg/L ozone was determined. Antibiotic resistance (AR) of the isolates was not correlating with higher tolerance against ozone. Except for ampicillin resistant E. coli strains, which showed a trend towards increased resistance, E. coli strains that were also resistant against cotrimoxazol, ciprofloxacin or a combination of the three antibiotics were similarly or less resistant against ozone than antibiotic sensitive strains. Pigment-producing Enterococcus casseliflavus and Staphylococcus aureus seemed to be more resistant against ozone than non-pigmented species of these genera. Furthermore, aggregation or biofilm formation apparently protected bacteria in subsurface layers from inactivation by ozone. The relatively large variance of tolerance against ozone may indicate that resistance to ozone inactivation most probably depends on several factors, where AR, if at all, does not play a major role. PMID:26608763

  5. The importance of growth kinetic analysis in determining bacterial susceptibility against antibiotics and silver nanoparticles

    PubMed Central

    Theophel, Karsten; Schacht, Veronika J.; Schlüter, Michael; Schnell, Sylvia; Stingu, Catalina-Suzana; Schaumann, Reiner; Bunge, Michael

    2014-01-01

    Routine antibiotics susceptibility testing still relies on standardized cultivation-based analyses, including measurement of inhibition zones in conventional agar diffusion tests and endpoint turbidity-based measurements. Here, we demonstrate that common off-line monitoring and endpoint determination after 18–24 h could be insufficient for reliable growth-dependent evaluation of antibiotic susceptibility. Different minimal inhibitory concentrations were obtained in 20- and 48 h microdilution plate tests using an Enterococcus faecium clinical isolate (strain UKI-MB07) as a model organism. Hence, we used an on-line kinetic assay for simultaneous cultivation and time-resolved growth analysis in a 96-well format instead of off-line susceptibility testing. Growth of the Enterococcus test organism was delayed up to 30 h in the presence of 0.25 μg mL-1 of vancomycin and 8 μg mL-1 of fosfomycin, after which pronounced growth was observed. Despite the delayed onset of growth, treatment with fosfomycin, daptomycin, fusidic acid, cefoxitin, or gentamicin resulted in higher maximum growth rates and/or higher final optical density values compared with antibiotic-free controls, indicating that growth stimulation and hormetic effects may occur with extended exposure to sublethal antibiotic concentrations. Whereas neither maximum growth rate nor final cell density correlated with antibiotic concentration, the lag phase duration for some antibiotics was a more meaningful indicator of dose-dependent growth inhibition. Our results also reveal that non-temporal growth profiles are only of limited value for cultivation-based antimicrobial silver nanoparticle susceptibility testing. The exposure to Ag(0) nanoparticles led to plasma membrane damage in a concentration-dependent manner and induced oxidative stress in Enterococcus faecium UKI-MB07, as shown by intracellular ROS accumulation. PMID:25426104

  6. Occurrence and Antibiotic Susceptibility of Listeria Species in Turkey Meats

    PubMed Central

    Ardıç, Mustafa

    2015-01-01

    The aims of this study were to investigate the occurrence of Listeria species in turkey meats and to check the antimicrobial susceptibility of the isolated strains. Hundred and fifteen raw turkey meat samples were randomly collected from the supermarkets, butchers and restaurants. Strain isolation and identification were made according to the ISO11290-1 method. Antimicrobial susceptibility was determined by the standard disc diffusion method. A total of 47 Listeria spp. were isolated from 115 (40.9%) raw turkey meat samples. The isolates were distributed between L. monocytogenes (25.53%), L. innocua (34.04%), L. grayi (31.91%) and L. welshimeri (8.51%). A total of 55.3 % of Listeria spp. isolates were multi-resistant to at least 3 of the antimicrobial agent tested. The level of multi-resistance was higher in L. monocytogenes strains (66.7%) than in L. innocua (62.5%) and L. grayi (53.3%). Listeria spp. isolates were highly resistant to ampicillin, cephalothin, penicillin, meticillin, oxacillin, and trimethoprime-sulfamethoxazole. The isolates particularly L. monocytogenes are increasingly resistant to one or more antibiotics and may represent a potential risk for public health because these antibiotics are common used in treatment of listeriosis. The correct and controlled use of antibiotics in veterinary medicine is important to the emergence of resistant strains. PMID:26761896

  7. Antibiotics in neonatal life increase murine susceptibility to experimental psoriasis

    PubMed Central

    Zanvit, Peter; Konkel, Joanne E.; Jiao, Xue; Kasagi, Shimpei; Zhang, Dunfang; Wu, Ruiqing; Chia, Cheryl; Ajami, Nadim J.; Smith, Daniel P.; Petrosino, Joseph F.; Abbatiello, Brittany; Nakatsukasa, Hiroko; Chen, Qianming; Belkaid, Yasmine; Chen, Zi-Jiang; Chen, WanJun

    2015-01-01

    Psoriasis is an inflammatory skin disease affecting ∼2% of the world's population, but the aetiology remains incompletely understood. Recently, microbiota have been shown to differentially regulate the development of autoimmune diseases, but their influence on psoriasis is incompletely understood. We show here that adult mice treated with antibiotics that target Gram-negative and Gram-positive bacteria develop ameliorated psoriasiform dermatitis induced by imiquimod, with decreased pro-inflammatory IL-17- and IL-22-producing T cells. Surprisingly, mice treated neonatally with these antibiotics develop exacerbated psoriasis induced by imiquimod or recombinant IL-23 injection when challenged as adults, with increased IL-22-producing γδ+ T cells. 16S rRNA gene compositional analysis reveals that neonatal antibiotic-treatment dysregulates gut and skin microbiota in adults, which is associated with increased susceptibility to experimental psoriasis. This link between neonatal antibiotic-mediated imbalance in microbiota and development of experimental psoriasis provides precedence for further investigation of its specific aetiology as it relates to human psoriasis. PMID:26416167

  8. Salmonella on Raw Poultry in Retail Markets in Guatemala: Levels, Antibiotic Susceptibility, and Serovar Distribution.

    PubMed

    Jarquin, Claudia; Alvarez, Danilo; Morales, Oneida; Morales, Ana Judith; López, Beatriz; Donado, Pilar; Valencia, Maria F; Arévalo, Alejandra; Muñoz, Fredy; Walls, Isabel; Doyle, Michael P; Alali, Walid Q

    2015-09-01

    The objective of this study was to determine Salmonella numbers on retail raw chicken carcasses in Guatemala and to phenotypically characterize the isolates (serotyping and antibiotic susceptibility). In total, 300 chicken carcasses were collected from seven departments in Guatemala. Salmonella numbers were determined using the most-probable-number method following the U. S. Department of Agriculture's Food Safety and Inspection Service protocol. In total, 103 isolates were obtained, all of which were tested for antibiotic susceptibility, whereas 46 isolates were serotyped. Overall, Salmonella prevalence and mean number (mean log most probable number per carcass) was 34.3% and 2.3 (95% confidence interval: 2.1 to 2.5), respectively. Significant differences (P < 0.05) in Salmonella prevalence were found by storage condition (refrigerated or ambient temperature), market type (wet markets, supermarkets, and independent poultry stores), chicken production system (integrated or nonintegrated production company), and chicken skin color (white or yellow). Chickens produced by integrated companies had lower Salmonella numbers (P < 0.05) than nonintegrated companies, and white-skin carcasses had lower numbers (P < 0.05) than yellow-skin carcasses. Among 13 different Salmonella serovars identified, Paratyphi B (34.8%) was most prevalent, followed by Heidelberg (16.3%) and Derby (11.6%). Of all the Salmonella isolates, 59.2% were resistant to one to three antibiotics and 13.6% to four or more antibiotics. Among all the serovars obtained, Salmonella Paratyphi B and Heidelberg were the most resistant to the antibiotics tested. Salmonella levels and antibiotic resistant profiles among isolates from raw poultry at the retail market level were high relative to other reports from North and South America. These data can be used by Guatemalan stakeholders to develop risk assessment models and support further research opportunities to control transmission of Salmonella spp. and

  9. Childhood Septicemia in Nepal: Documenting the Bacterial Etiology and Its Susceptibility to Antibiotics

    PubMed Central

    Nepal, Hari Prasad; Neopane, Puja; Rimal, Brihaspati; Mandal, Fuleshwar; Ansari, Safiur Rahman; Chapagain, Moti Lal

    2014-01-01

    Introduction. Children are among the most vulnerable population groups to contract illnesses. The varying microbiological pattern of septicemia warrants the need for an ongoing review of the causative organisms and their antimicrobial susceptibility pattern. Therefore, the objective of this study was to document the bacterial etiology of childhood septicemia and its antibiotic susceptibility profile. Methods. Cross-sectional type of study in 1630 suspected patients was conducted at CMCTH from January 2012 to December 2013. Blood samples were collected aseptically for culture. The organisms grown were identified by standard microbiological methods recommended by American Society for Microbiology (ASM) and subjected to antibiotic susceptibility testing by modified Kirby-Bauer disk diffusion method. Methicillin resistance was confirmed using cefoxitin and oxacillin disks methods. Results. Septicemia was detected in 172 (10.6%) cases. Among Gram-positive organisms, coagulase negative staphylococci (CoNS) were leading pathogen and Acinetobacter spp. were leading pathogen among Gram-negative isolates. Vancomycin, teicoplanin, and clindamycin were the most effective antibiotics against Gram-positive isolates while amikacin was effective against Gram-positive as well as Gram-negative isolates. Methicillin resistance was detected in 44.4% of Staphylococcus aureus. Conclusions. This study has highlighted the burden of bacterial etiology for septicemia among children in a tertiary care center of central Nepal. PMID:25610467

  10. Antibiotic susceptibility in prostate-derived Propionibacterium acnes isolates.

    PubMed

    Olsson, Jan; Davidsson, Sabina; Unemo, Magnus; Mölling, Paula; Andersson, Swen-Olov; Andrén, Ove; Söderquist, Bo; Sellin, Mats; Elgh, Fredrik

    2012-10-01

    The aim of this study was to determine antibiotic susceptibility of Propionibacterium acnes isolates from prostate. Prostate-derived P. acnes isolates (n = 24, Umeå & Örebro, Sweden, 2007-2010) and a panel of control strains (n = 25, Sweden) collected from skin and deep infections were assessed for resistance to penicillin G, piperacillin-tazobactam, imipenem, gentamicin, azithromycin, erythromycin, vancomycin, ciprofloxacin, moxifloxacin, tetracycline, tigecycline, fusidic acid, clindamycin, rifampicin, linezolid, daptomycin, trimethoprim-sulfamethoxazole, and metronidazole. In addition, the isolates were tested for inducible clindamycin resistance. All prostate derived P. acnes isolates displayed wild-type distribution of MIC-values, without evidence of acquired resistance. In the reference panel, 5 of 25 isolates had acquired macrolide resistance with cross-resistance to azithromycin, clindamycin, and erythromycin. In addition, one of these isolates was resistant to tetracycline. PMID:22958285

  11. Impact of space flight on bacterial virulence and antibiotic susceptibility.

    PubMed

    Taylor, Peter William

    2015-01-01

    Manned space flight induces a reduction in immune competence among crew and is likely to cause deleterious changes to the composition of the gastrointestinal, nasal, and respiratory bacterial flora, leading to an increased risk of infection. The space flight environment may also affect the susceptibility of microorganisms within the spacecraft to antibiotics, key components of flown medical kits, and may modify the virulence characteristics of bacteria and other microorganisms that contaminate the fabric of the International Space Station and other flight platforms. This review will consider the impact of true and simulated microgravity and other characteristics of the space flight environment on bacterial cell behavior in relation to the potential for serious infections that may appear during missions to astronomical objects beyond low Earth orbit. PMID:26251622

  12. Impact of space flight on bacterial virulence and antibiotic susceptibility

    PubMed Central

    Taylor, Peter William

    2015-01-01

    Manned space flight induces a reduction in immune competence among crew and is likely to cause deleterious changes to the composition of the gastrointestinal, nasal, and respiratory bacterial flora, leading to an increased risk of infection. The space flight environment may also affect the susceptibility of microorganisms within the spacecraft to antibiotics, key components of flown medical kits, and may modify the virulence characteristics of bacteria and other microorganisms that contaminate the fabric of the International Space Station and other flight platforms. This review will consider the impact of true and simulated microgravity and other characteristics of the space flight environment on bacterial cell behavior in relation to the potential for serious infections that may appear during missions to astronomical objects beyond low Earth orbit. PMID:26251622

  13. Antibiotic susceptibility of Lactobacillus strains isolated from domestic geese.

    PubMed

    Dec, M; Wernicki, A; Puchalski, A; Urban-Chmiel, R

    2015-01-01

    The aim of this study was to determine the antibiotic susceptibility of 93 Lactobacillus strains isolated from domestic geese raised on Polish farms. The minimal inhibitory concentration (MIC) of 13 antimicrobial substances was determined by the broth microdilution method. All strains were sensitive to the cell wall inhibitors ampicillin and amoxicillin (MIC ≤ 8 μg/ml). Resistance to inhibitors of protein synthesis and to fluoroquinolone inhibitors of replication was found in 44.1% and 60.2% of isolates, respectively; 26.9% strains were resistant to neomycin (MIC ≥ 64 μg/ml), 23.6% to tetracycline (MIC ≥ 32 μg/ml), 15% to lincomycin (MIC ≥ 64 μg/ml), 18.3% to doxycycline (MIC ≥ 32 μg/ml), 9.7% to tylosin (MIC ≥ 32 μg/ml), 56% to flumequine (MIC ≥ 256 μg/ml) and 22.6% to enrofloxacin (MIC ≥ 64 μg/ml). Bimodal distribution of MICs indicative of acquired resistance and unimodal distribution of the high MIC values indicative of intrinsic resistance were correlated with Lactobacillus species. Eleven (11.8%) strains displayed multiple resistance for at least three classes of antibiotics. Data derived from this study can be used as a basis for reviewing current microbiological breakpoints for categorisation of susceptible and resistant strains of Lactobacillus genus and help to assess the hazards associated with the occurrence of drug resistance among natural intestinal microflora. PMID:26105622

  14. [Prevalence of multidrug-resistant Proteus spp. strains in clinical specimens and their susceptibility to antibiotics].

    PubMed

    Reśliński, Adrian; Gospodarek, Eugenia; Mikucka, Agnieszka

    2005-01-01

    Proteus sp. are opportunistic microorganisms which cause urinary tract and wounds infections, bacteriaemia and sepsis. The aim of this study was analysis of prevalence of multidrug-resistant Proteus sp. strains in clinical specimens and evaluation of their susceptibility to selected antibiotics. The study was carried out of 1499 Proteus sp. strains were isolated in 2000-2003 from patients of departments and dispensaries of the University Hospital CM in Bydgoszcz UMK in Torun. The strains were identified on the basis of appearance of bacterial colonies on bloody and McConkey's agars, movement ability, indole and urease production and in questionable cases biochemical profile in ID GN or ID E (bio-Mérieux) tests was also included. Antibiotic susceptibility was tested by disk diffusion method. Isolated strains were regarded as multidrug-resistant when they were resistant to three kinds of antibiotics at least. Received Proteus sp. the most frequently belonged to P. mirabilis species (92.3%). Most of these bacteria were isolated from urine from patients of Rehabilitation Clinic. All of multidrug-resistant strains were resistant to penicillins and cephalosporins, 98.9% to co-trimoxazole, 77.7% to quinolones, 63.8% to tetracyclines, 38.5% to aminoglycosides, 19.3% to monobactams and 3.4% to carbapenems. Almost 25% multidrug-resistant Proteus sp. produced ESBL. PMID:16134389

  15. [The comparison of antibiotic susceptibilities of uropathogenic Escherichia coli isolates in transition from CLSI to EUCAST].

    PubMed

    Süzük, Serap; Kaşkatepe, Banu; Avcıküçük, Havva; Aksaray, Sebahat; Başustaoğlu, Ahmet

    2015-10-01

    Determination of treatment protocols for infections according to antimicrobial susceptibility test (AST) results is are important for controlling the problem of antibiotic resistance. Two standards are widely used in the world. One of them is Clinical Laboratory Standards Institute (CLSI) standards used in Turkey for many years and the other is the European Committee on Antimicrobial Susceptibility Testing (EUCAST) standards which is used in European Union member countries and came into use in 2015 in Turkey. Since the EUCAST standards had higher clinical sensitivity limits particularly for gram-negative bacilli compared to CLSI (2009) standards, there will be some changes in antibiotic resistance profiles of Turkey with the use of EUCAST. CLSI has changed zone diameters after 2009 versions and the differences between the two standards were brought to a minimum level. Knowledge of local epidemiological data is important to determine empirical therapy which will be used in urinary tract infections (UTI). The aim of this study was to determine the differences of antibiotic susceptibility zone diameters based on our local epidemiological data among uropathogenic Escherichia coli isolates according to EUCAST 2014 and CLSI 2014 standards. A total of 298 E.coli strains isolated from urine samples as the cause of uncomplicated acute UTI agents, were included in the study. Isolates were identified by conventional methods and with BBL Crystal E/NF ID System (Becton Dickinson, USA). AST was performed with Kirby Bauer disk diffusion method and results were evaluated and interpreted according to the CLSI 2014 and EUCAST 2014 standards. According to the results, susceptibility rates of isolates against amikacin (100%) and trimethoprim-sulfamethoxazole (63.09%) were identical in both standards. However, statistically significant differences were observed between CLSI and EUCAST standards in terms of susceptibilities against gentamicin (91.95% and 84.56%, respectively; p= 0

  16. Antibiotic Susceptibility Testing of the Gram-Negative Bacteria Based on Flow Cytometry

    PubMed Central

    Saint-Ruf, Claude; Crussard, Steve; Franceschi, Christine; Orenga, Sylvain; Ouattara, Jasmine; Ramjeet, Mahendrasingh; Surre, Jérémy; Matic, Ivan

    2016-01-01

    Rapidly treating infections with adequate antibiotics is of major importance. This requires a fast and accurate determination of the antibiotic susceptibility of bacterial pathogens. The most frequently used methods are slow because they are based on the measurement of growth inhibition. Faster methods, such as PCR-based detection of determinants of antibiotic resistance, do not always provide relevant information on susceptibility, particularly that which is not genetically based. Consequently, new methods, such as the detection of changes in bacterial physiology caused by antibiotics using flow cytometry and fluorescent viability markers, are being explored. In this study, we assessed whether Alexa Fluor® 633 Hydrazide (AFH), which targets carbonyl groups, can be used for antibiotic susceptibility testing. Carbonylation of cellular macromolecules, which increases in antibiotic-treated cells, is a particularly appropriate to assess for this purpose because it is irreversible. We tested the susceptibility of clinical isolates of Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa, to antibiotics from the three classes: β-lactams, aminoglycosides, and fluoroquinolones. In addition to AFH, we used TO-PRO®-3, which enters cells with damaged membranes and binds to DNA, and DiBAC4 (3), which enters cells with depolarized membranes. We also monitored antibiotic-induced morphological alterations of bacterial cells by analyzing light scattering signals. Although all tested dyes and light scattering signals allowed for the detection of antibiotic-sensitive cells, AFH proved to be the most suitable for the fast and reliable detection of antibiotic susceptibility. PMID:27507962

  17. Antibiotic Susceptibility Testing of the Gram-Negative Bacteria Based on Flow Cytometry.

    PubMed

    Saint-Ruf, Claude; Crussard, Steve; Franceschi, Christine; Orenga, Sylvain; Ouattara, Jasmine; Ramjeet, Mahendrasingh; Surre, Jérémy; Matic, Ivan

    2016-01-01

    Rapidly treating infections with adequate antibiotics is of major importance. This requires a fast and accurate determination of the antibiotic susceptibility of bacterial pathogens. The most frequently used methods are slow because they are based on the measurement of growth inhibition. Faster methods, such as PCR-based detection of determinants of antibiotic resistance, do not always provide relevant information on susceptibility, particularly that which is not genetically based. Consequently, new methods, such as the detection of changes in bacterial physiology caused by antibiotics using flow cytometry and fluorescent viability markers, are being explored. In this study, we assessed whether Alexa Fluor® 633 Hydrazide (AFH), which targets carbonyl groups, can be used for antibiotic susceptibility testing. Carbonylation of cellular macromolecules, which increases in antibiotic-treated cells, is a particularly appropriate to assess for this purpose because it is irreversible. We tested the susceptibility of clinical isolates of Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa, to antibiotics from the three classes: β-lactams, aminoglycosides, and fluoroquinolones. In addition to AFH, we used TO-PRO®-3, which enters cells with damaged membranes and binds to DNA, and DiBAC4 (3), which enters cells with depolarized membranes. We also monitored antibiotic-induced morphological alterations of bacterial cells by analyzing light scattering signals. Although all tested dyes and light scattering signals allowed for the detection of antibiotic-sensitive cells, AFH proved to be the most suitable for the fast and reliable detection of antibiotic susceptibility. PMID:27507962

  18. Shattering a myth - Whooping cough susceptible to antibiotics.

    PubMed

    Syed, Muhammad Ali; Jamil, Bushra; Bokhari, Habib

    2016-05-01

    Bordetella parapertussis is the causative agent of a milder form of pertussis or whooping cough. Little is reported about the antibiotic resistance patterns and mechanism of drug resistance of Bordetella parapertussis. The objective of this study has been to investigate antimicrobial resistance, distribution of integrons and presence of gene cassettes to quinolones (qnr) and sulfonamides (sul) among B. parapertussis strains' isolated from Pakistan. Thirty-five (35) samples were collected from various hospitals of Pakistan from children (median age 3 years) with pertussis-like symptoms, all were tested and confirmed to be B. Parapertussis. Resistance profile of Ampicillin, Cephalexin, Sulphamethoxazole, Chloramphenicol, Ofloxacin, Nalidixic acid, Gentamycin and Erythromycin were investigated through all samples. Majority of the isolates were found to be resistant to the afore-mentioned antibiotics except erythromycin. All isolates were resistant to quinolones phenotypically, but qnr genes were detected in only 25.7% (9/35) of isolates. On the other hand, 71.4% (25/35) isolates were resistant to sulfonamides phenotypically. From these 71% strains showing phenotypical resistance, 96% (24/25) were found to possess sul genes. Only two isolates were carrying class 1 integrons, which also harbored sul gene and qnr gene cassettes. It can be safely concluded that the phenotypic resistance patterns seemed mostly independent of presence of integrons. However, interestingly both integrons harboring strains were resistant to quinolones and sulfonamides and also possessed qnr and sul genes. PMID:27166543

  19. Antibiotic-induced shifts in the mouse gut microbiome and metabolome increase susceptibility to Clostridium difficile infection

    PubMed Central

    Theriot, Casey M.; Koenigsknecht, Mark J.; Carlson, Paul E.; Hatton, Gabrielle E.; Nelson, Adam M.; Li, Bo; Huffnagle, Gary B.; Li, Jun; Young, Vincent B.

    2014-01-01

    Antibiotics can have significant and long lasting effects on the gastrointestinal tract microbiota, reducing colonization resistance against pathogens including Clostridium difficile. Here we show that antibiotic treatment induces substantial changes in the gut microbial community and in the metabolome of mice susceptible to C. difficile infection. Levels of secondary bile acids, glucose, free fatty acids, and dipeptides decrease, whereas those of primary bile acids and sugar alcohols increase, reflecting the modified metabolic activity of the altered gut microbiome. In vitro and ex vivo analyses demonstrate that C. difficile can exploit specific metabolites that become more abundant in the mouse gut after antibiotics, including primary bile acid taurocholate for germination, and carbon sources mannitol, fructose, sorbitol, raffinose and stachyose for growth. Our results indicate that antibiotic-mediated alteration of the gut microbiome converts the global metabolic profile to one that favors C. difficile germination and growth. PMID:24445449

  20. Antibiotic susceptibility of urinary isolates in nursing home residents consuming cranberry capsules versus placebo

    PubMed Central

    Madden, Gregory R.; Argraves, Stephanie M.; Van Ness, Peter H.; Juthani-Mehta, Manisha

    2015-01-01

    Antimicrobial susceptibility of urinary isolates is compared amongst nursing home participants from a randomized controlled trial of cranberry capsules versus placebo. We hypothesized that cranberry spares non-Escherichia coli Enterobacteriaceae, which tend to be less susceptible to oral antibiotics. Analyses showed no differences in susceptibility or proportions of non-E. coli Enterobacteriaceae. PMID:25695180

  1. Antibiotic susceptibilities, streptococcal pyrogenic exotoxin gene profiles among clinical isolates of group C or G Streptococcus dysgalactiae subsp. equisimilis & of group G S. anginosus group at a tertiary care centre

    PubMed Central

    Behera, Bijayini; Mathur, Purva; Bhardwaj, Nidhi; Jain, Neetu; Misra, M. C.; Kapil, Arti; Singh, Sarman

    2014-01-01

    Background & objectives: Group C and group G streptococci (together GCGS) are often regarded as commensal bacteria and their role in streptococcal disease burden is under-recognized. While reports of recovery of GCGS from normally sterile body sites are increasing, their resistance to macrolides, fluoroquinolone further warrants all invasive β haemolytic streptococci to be identified to the species level and accurately tested for antimicrobial susceptibility. This study was aimed to determine the prevalence, clinical profile, antimicrobial susceptibility and streptococcal pyrogenic exotoxin gene profile (speA, speB, speC, speF, smeZ, speI, speM, speG, speH and ssa) of GCGS obtained over a period of two years at a tertiary care centre from north India. Methods: The clinical samples were processed as per standard microbiological techniques. β-haemolytic streptococci (BHS) were characterized and grouped. Antimicrobial susceptibility of GCGS was performed using disk diffusion method. All GCGS were characterized for the presence of streptococcal pyrogenic exotoxins (spe) and spe genes were amplified by PCR method. Results: GCGS (23 GGS, 2GCS) comprised 16 per cent of β haemolytic streptococci (25/142 βHS, 16%) isolated over the study period. Of the 25 GCGS, 22 (88%) were recovered from pus, two (8%) from respiratory tract, whereas one isolate was recovered from blood of a fatal case of septicaemia. Of the total 23 GGS isolates, 18 (78%) were identified as Streptococcus dysgalactiae subsp equisimilis (SDSE, large-colony phenotype), five (21%) were Streptococcus anginosus group (SAG, small-colony phenotype). The two GCS were identified as SDSE. All GCGS isolates were susceptible to penicillin, vancomycin, and linezolid. Tetracycline resistance was noted in 50 per cent of SDSE isolates. The rates of macrolide and fluoroquinolone resistance in SDSE were low. Twelve of the 20 SDSE isolates were positive for one or more spe genes, with five of the SDSE isolates

  2. Bacterial Cytological Profiling (BCP) as a Rapid and Accurate Antimicrobial Susceptibility Testing Method for Staphylococcus aureus

    PubMed Central

    Quach, D.T.; Sakoulas, G.; Nizet, V.; Pogliano, J.; Pogliano, K.

    2016-01-01

    Successful treatment of bacterial infections requires the timely administration of appropriate antimicrobial therapy. The failure to initiate the correct therapy in a timely fashion results in poor clinical outcomes, longer hospital stays, and higher medical costs. Current approaches to antibiotic susceptibility testing of cultured pathogens have key limitations ranging from long run times to dependence on prior knowledge of genetic mechanisms of resistance. We have developed a rapid antimicrobial susceptibility assay for Staphylococcus aureus based on bacterial cytological profiling (BCP), which uses quantitative fluorescence microscopy to measure antibiotic induced changes in cellular architecture. BCP discriminated between methicillin-susceptible (MSSA) and -resistant (MRSA) clinical isolates of S. aureus (n = 71) within 1–2 h with 100% accuracy. Similarly, BCP correctly distinguished daptomycin susceptible (DS) from daptomycin non-susceptible (DNS) S. aureus strains (n = 20) within 30 min. Among MRSA isolates, BCP further identified two classes of strains that differ in their susceptibility to specific combinations of beta-lactam antibiotics. BCP provides a rapid and flexible alternative to gene-based susceptibility testing methods for S. aureus, and should be readily adaptable to different antibiotics and bacterial species as new mechanisms of resistance or multidrug-resistant pathogens evolve and appear in mainstream clinical practice. PMID:26981574

  3. Bacterial Cytological Profiling (BCP) as a Rapid and Accurate Antimicrobial Susceptibility Testing Method for Staphylococcus aureus.

    PubMed

    Quach, D T; Sakoulas, G; Nizet, V; Pogliano, J; Pogliano, K

    2016-02-01

    Successful treatment of bacterial infections requires the timely administration of appropriate antimicrobial therapy. The failure to initiate the correct therapy in a timely fashion results in poor clinical outcomes, longer hospital stays, and higher medical costs. Current approaches to antibiotic susceptibility testing of cultured pathogens have key limitations ranging from long run times to dependence on prior knowledge of genetic mechanisms of resistance. We have developed a rapid antimicrobial susceptibility assay for Staphylococcus aureus based on bacterial cytological profiling (BCP), which uses quantitative fluorescence microscopy to measure antibiotic induced changes in cellular architecture. BCP discriminated between methicillin-susceptible (MSSA) and -resistant (MRSA) clinical isolates of S. aureus (n = 71) within 1-2 h with 100% accuracy. Similarly, BCP correctly distinguished daptomycin susceptible (DS) from daptomycin non-susceptible (DNS) S. aureus strains (n = 20) within 30 min. Among MRSA isolates, BCP further identified two classes of strains that differ in their susceptibility to specific combinations of beta-lactam antibiotics. BCP provides a rapid and flexible alternative to gene-based susceptibility testing methods for S. aureus, and should be readily adaptable to different antibiotics and bacterial species as new mechanisms of resistance or multidrug-resistant pathogens evolve and appear in mainstream clinical practice. PMID:26981574

  4. Natural antibiotic susceptibility of Escherichia coli, Shigella, E. vulneris, and E. hermannii strains.

    PubMed

    Stock, I; Wiedemann, B

    1999-03-01

    The natural antibiotic susceptibility of 139 Escherichia coli strains (including 18 enterohemorrhagic E. coli), 73 Shigella strains (S. sonnei (n = 37), S. flexneri (n = 29), S. boydii (n = 6), S. dysenteriae (n = 1)), 23 E. vulneris, and 20 E. hermannii strains toward 71 antibiotics was examined. MICs were determined using a microdilution procedure. All examined taxa were naturally sensitive/intermediate toward tetracyclines, aminoglycosides, some penicillins (amoxycillin/clavulanate, ampicillin/sulbactam, piperacillin [with and without tazobactam], mezlocillin, azlocillin), cephalosporins, carbapenems, monobactams, quinolones, trimethoprim, cotrimoxazole, and chloramphenicol and were naturally resistant/intermediate toward benzylpenicillin, oxacillin, macrolides, lincosamides, glycopeptides, rifampicin, and fusidic acid. No differences in natural antibiotic susceptibility were seen between enterohemorrhagic and other E. coli strains. Likewise, with one exception, no significant differences in natural antibiotic susceptibility were seen either among the Shigella subgroups or between Shigella and E. coli. The natural population of S. flexneri was slightly more susceptible to chloramphenicol than the natural populations of other taxa within the Shigella-E. coli complex. E. vulneris and E. hermannii showed susceptibility patterns to many antibiotics similar to Shigella and E. coli, but there were other antibiotics toward which there were significant differences in natural susceptibility. E. vulneris and E. hermannii were less susceptible to nitrofurantoin and slightly more susceptible to several aminoglycosides than E. coli and Shigella. E. hermannii was the only species that was naturally resistant/intermediate to ticarcillin and amoxycillin (DIN standard). The addition of clavulanic acid to the latter resulted in a decrease of seven twofold dilution steps (E. vulneris: four twofold dilution steps, E. coli/Shigella: two twofold dilution steps) of the MICs of the

  5. The Use of Machine Learning Methodologies to Analyse Antibiotic and Biocide Susceptibility in Staphylococcus aureus

    PubMed Central

    Coelho, Joana Rosado; Carriço, João André; Knight, Daniel; Martínez, Jose-Luis; Morrissey, Ian; Oggioni, Marco Rinaldo; Freitas, Ana Teresa

    2013-01-01

    Background The rise of antibiotic resistance in pathogenic bacteria is a significant problem for the treatment of infectious diseases. Resistance is usually selected by the antibiotic itself; however, biocides might also co-select for resistance to antibiotics. Although resistance to biocides is poorly defined, different in vitro studies have shown that mutants presenting low susceptibility to biocides also have reduced susceptibility to antibiotics. However, studies with natural bacterial isolates are more limited and there are no clear conclusions as to whether the use of biocides results in the development of multidrug resistant bacteria. Methods The main goal is to perform an unbiased blind-based evaluation of the relationship between antibiotic and biocide reduced susceptibility in natural isolates of Staphylococcus aureus. One of the largest data sets ever studied comprising 1632 human clinical isolates of S. aureus originated worldwide was analysed. The phenotypic characterization of 13 antibiotics and 4 biocides was performed for all the strains. Complex links between reduced susceptibility to biocides and antibiotics are difficult to elucidate using the standard statistical approaches in phenotypic data. Therefore, machine learning techniques were applied to explore the data. Results In this pioneer study, we demonstrated that reduced susceptibility to two common biocides, chlorhexidine and benzalkonium chloride, which belong to different structural families, is associated to multidrug resistance. We have consistently found that a minimum inhibitory concentration greater than 2 mg/L for both biocides is related to antibiotic non-susceptibility in S. aureus. Conclusions Two important results emerged from our work, one methodological and one other with relevance in the field of antibiotic resistance. We could not conclude on whether the use of antibiotics selects for biocide resistance or vice versa. However, the observation of association between multiple

  6. Antibiotic susceptibility of bacteria isolated from infections in cats and dogs throughout Europe (2002-2009).

    PubMed

    Kroemer, Stéphane; El Garch, Farid; Galland, Delphine; Petit, Jean-Luc; Woehrle, Frédérique; Boulouis, Henri-Jean

    2014-03-01

    A monitoring program of the pre-treatment susceptibility of clinical isolates of bacteria from diseased dogs and cats was active between the years 2002 and 2009. Susceptibility of each isolated strain to a panel of nine antibiotics (amoxicillin/clavulanic acid, ampicillin, penicillin, clindamycin, doxycycline, enrofloxacin, marbofloxacin, trimethoprim and trimethoprim/sulfamethoxazole) was assessed. The Minimum Inhibitory Concentration (MIC) of marbofloxacin was also determined by a standardized microdilution technique following CLSI recommendations. In total, 1857 bacterial strains were collected throughout Europe from cases of otitis, respiratory, urinary and dermatological infections. Although bacterial susceptibility varied for each of the antibiotics within the panel, patterns of susceptibility were similar to those described in the literature for comparable time periods and geographical areas. With a clinical resistance varying from 0 to 14.48% against the isolated strains, marbofloxacin susceptibility was very high and remains an effective antibiotic for the treatment of otitis, urinary, respiratory and dermatological infections in companion animals. PMID:24447508

  7. Susceptibility of antibiotic-resistant and antibiotic-sensitive foodborne pathogens to acid anionic sanitizers.

    PubMed

    Lopes, J A

    1998-10-01

    Acid anionic sanitizers for treatment of fruits and vegetables were prepared using ingredients generally recognized as safe by the U.S. Food and Drug Administration or anionic surfactants and organic acid food additives. They met the regulatory definition as sanitizers by showing bactericidal efficacy of 99.999% in 30 s against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 11229. These sanitizers showed a broad spectrum of microbicidal activity against both gram-positive and gram-negative bacteria. Antibiotic-sensitive and resistant strains of Listeria monocytogenes and Salmonella typhimurium were equally susceptible to these sanitizers. The acid anionic sanitizers showed microbicidal efficacy equal to that of hypochlorite against Aeromonas hydrophila, E. coli O157:H7, L. monocytogenes, Pseudomonas aeruginosa, S. typhimurium, and S. aureus. Unlike most other sanitizers, these agents do not covalently react with organic components of food; unlike cationic agents, they do not leave residues. The acid anionic sanitizers are prepared using stable, biodegradable, and nontoxic ingredients. Rapid microbicidal activity and the ease of storage, transportation, and use make these sanitizers an attractive alternative to hypochlorite for sanitizing fruits and vegetables. PMID:9798163

  8. Mycobacterium kansasii: antibiotic susceptibility and PCR-restriction analysis of clinical isolates.

    PubMed

    da Silva Telles, Maria Alice; Chimara, Erica; Ferrazoli, Lucilaine; Riley, Lee W

    2005-10-01

    Mycobacterium kansasii is the second most common cause of non-tuberculosis mycobacterial diseases in Sao Paulo, Brazil. An important component of the management of infections caused by this organism is antibiotic susceptibility testing. The objective of this study was to determine the drug susceptibility profiles and genotypes of clinical isolates of M. kansasii obtained from patients with or without an infection that met the American Thoracic Society's case definition criteria of M. kansasii disease. One hundred and sixty-nine clinical isolates of M. kansasii collected between 1993 and 1998 in Sao Paulo, Brazil, were tested consecutively. The isolates were genotyped by PCR restriction-enzyme pattern analysis (PRA). Most of the M. kansasii strains were susceptible to isoniazid, streptomycin, rifabutin, rifampicin, clarithromycin, ethionamide, amikacin, clofazimine and cycloserine, and resistant to ethambutol, ciprofloxacin and doxycycline. Of 169 isolates, 167 belonged to the type I PRA genotype and one each belonged to type II and III genotypes. There was no correlation between PRA subtype and M. kansasii disease according to the American Thoracic Society case definition. Clinical trials may be needed to better correlate MIC values with treatment outcomes to identify appropriate parameters for drug-resistance testing of M. kansasii. PMID:16157553

  9. In Vitro Antibiotic Susceptibilities of Yersinia pestis Determined by Broth Microdilution following CLSI Methods

    PubMed Central

    Hershfield, Jeremy; Marchand, Charles; Miller, Lynda; Halasohoris, Stephanie; Purcell, Bret K.; Worsham, Patricia L.

    2015-01-01

    In vitro susceptibilities to 45 antibiotics were determined for 30 genetically and geographically diverse strains of Yersinia pestis by the broth microdilution method at two temperatures, 28°C and 35°C, following Clinical and Laboratory Standards Institute (CLSI) methods. The Y. pestis strains demonstrated susceptibility to aminoglycosides, quinolones, tetracyclines, β-lactams, cephalosporins, and carbapenems. Only a 1-well shift was observed for the majority of antibiotics between the two temperatures. Establishing and comparing antibiotic susceptibilities of a diverse but specific set of Y. pestis strains by standardized methods and establishing population ranges and MIC50 and MIC90 values provide reference information for assessing new antibiotic agents and also provide a baseline for use in monitoring any future emergence of resistance. PMID:25583720

  10. Apparatus and process for determining the susceptibility of microorganisms to antibiotics

    NASA Technical Reports Server (NTRS)

    Gibson, Sandra F. (Inventor); Fadler, Norman L. (Inventor)

    1976-01-01

    A process for determining the susceptibility of microorganisms to antibiotics involves introducing a diluted specimen into discrete quantities of a selective culture medium which favors a specific microorganism in that the microorganism is sustained by the medium and when so sustained will change the optical characteristics of the medium. Only the specific microorganism will alter the optical characteristics. Some of the discrete quantities are blended with known antibiotics, while at least one is not. If the specimen contains the microorganisms favored by the selective medium, the optical characteristics of the discrete quantity of pure selective medium, that is the one without antibiotics, will change. If the antibiotics in any of the other discrete quantities are ineffective against the favored microorganisms, the optical characteristics of those quantities will likewise change. No change in the optical characteristics of a discrete quantity indicates that the favored microorganism is susceptible to the antibiotic in the quantity.

  11. How Porin Heterogeneity and Trade-Offs Affect the Antibiotic Susceptibility of Gram-Negative Bacteria

    PubMed Central

    Ferenci, Thomas; Phan, Katherine

    2015-01-01

    Variations in porin proteins are common in Gram-negative pathogens. Altered or absent porins reduce access of polar antibiotics across the outer membrane and can thus contribute to antibiotic resistance. Reduced permeability has a cost however, in lowering access to nutrients. This trade-off between permeability and nutritional competence is the source of considerable natural variation in porin gate-keeping. Mutational changes in this trade-off are frequently selected, so susceptibility to detergents and antibiotics is polymorphic in environmental isolates as well as pathogens. Understanding the mechanism, costs and heterogeneity of antibiotic exclusion by porins will be crucial in combating Gram negative infections. PMID:26506392

  12. A microfluidic platform for rapid, stress-induced antibiotic susceptibility testing of Staphylococcus aureus

    PubMed Central

    Kalashnikov, Maxim; Lee, Jean C.; Campbell, Jennifer; Sharon, Andre; Sauer-Budge, Alexis F.

    2012-01-01

    The emergence and spread of bacterial resistance to ever increasing classes of antibiotics intensifies the need for fast phenotype-based clinical tests for determining antibiotic susceptibility. Standard susceptibility testing relies on the passive observation of bacterial growth inhibition in the presence of antibiotics. In this paper, we present a novel microfluidic platform for antibiotic susceptibility testing basedon stress-activation of biosynthetic pathways that are the primary targets of antibiotics. We chose Staphylococcus aureus as a model system due to its clinical importance, and we selected bacterial cell wall biosynthesis as the primary target of both stress and antibiotic. Enzymatic and mechanical stresses were used to damage the bacterial cell wall, and a β-lactam antibiotic interfered with the repair process, resulting in rapid cell death of strains that harbor no resistance mechanism. In contrast, resistant bacteria remained viable under the assay conditions. Bacteria, covalently-bound to the bottom of the microfluidic channel, were subjected to mechanical shear stress created by flowing culture media through the microfluidic channel and to enzymatic stress with sub-inhibitory concentrations of the bactericidal agent lysostaphin. Bacterial cell death was monitored via fluorescence using the Sytox Green dead cell stain, and rates of killing were measured for the bacterial samples in the presence and absence of oxacillin. Using model susceptible (Sanger 476) and resistant (MW2) S. aureus strains, a metric was established to separate susceptible and resistant staphylococci based on normalized fluorescence values after 60 minutes of exposure to stress and antibiotic. Because this groundbreaking approach is not based on standard methodology, it circumvents the need for minimum inhibitory concentration (MIC) measurements and long wait times. We demonstrate the successful development of a rapid microfluidic-based and stress-activated antibiotic

  13. Cold Stress Makes Escherichia coli Susceptible to Glycopeptide Antibiotics by Altering Outer Membrane Integrity.

    PubMed

    Stokes, Jonathan M; French, Shawn; Ovchinnikova, Olga G; Bouwman, Catrien; Whitfield, Chris; Brown, Eric D

    2016-02-18

    A poor understanding of the mechanisms by which antibiotics traverse the outer membrane remains a considerable obstacle to the development of novel Gram-negative antibiotics. Herein, we demonstrate that the Gram-negative bacterium Escherichia coli becomes susceptible to the narrow-spectrum antibiotic vancomycin during growth at low temperatures. Heterologous expression of an Enterococcus vanHBX vancomycin resistance cluster in E. coli confirmed that the mechanism of action was through inhibition of peptidoglycan biosynthesis. To understand the nature of vancomycin permeability, we screened for strains of E. coli that displayed resistance to vancomycin at low temperature. Surprisingly, we observed that mutations in outer membrane biosynthesis suppressed vancomycin activity. Subsequent chemical analysis of lipopolysaccharide from vancomycin-sensitive and -resistant strains confirmed that suppression was correlated with truncations in the core oligosaccharide of lipopolysaccharide. These unexpected observations challenge the current understanding of outer membrane permeability, and provide new chemical insights into the susceptibility of E. coli to glycopeptide antibiotics. PMID:26853624

  14. Rapid bacterial antibiotic susceptibility test based on simple surface-enhanced Raman spectroscopic biomarkers

    PubMed Central

    Liu, Chia-Ying; Han, Yin-Yi; Shih, Po-Han; Lian, Wei-Nan; Wang, Huai-Hsien; Lin, Chi-Hung; Hsueh, Po-Ren; Wang, Juen-Kai; Wang, Yuh-Lin

    2016-01-01

    Rapid bacterial antibiotic susceptibility test (AST) and minimum inhibitory concentration (MIC) measurement are important to help reduce the widespread misuse of antibiotics and alleviate the growing drug-resistance problem. We discovered that, when a susceptible strain of Staphylococcus aureus or Escherichia coli is exposed to an antibiotic, the intensity of specific biomarkers in its surface-enhanced Raman scattering (SERS) spectra drops evidently in two hours. The discovery has been exploited for rapid AST and MIC determination of methicillin-susceptible S. aureus and wild-type E. coli as well as clinical isolates. The results obtained by this SERS-AST method were consistent with that by the standard incubation-based method, indicating its high potential to supplement or replace existing time-consuming methods and help mitigate the challenge of drug resistance in clinical microbiology. PMID:26997474

  15. Laser based enhancement of susceptibility of bacteria to antibiotic

    NASA Astrophysics Data System (ADS)

    Reznick, Yana; Banin, Ehud; Lipovsky, Anat; Lubart, Rachel; Zalevsky, Zeev

    2012-03-01

    Our objective is to test the effect of pulsed (Q-switched) and continuous wave (CW) laser light at wavelength of 532nm on the viability of free-living stationary phase bacteria with and without gentamicin (an antibiotic) treatment. Free living stationary phase gram negative bacteria (Pseudomonas aeruginosa strain PAO1) was immersed in Luria Broth (LB) solution and exposed to Q-switched and CW lasers with and without the addition of the antibiotic gentamicin. Cell viability was determined at different time points. Laser treatment alone did not reduce cell viability compared to untreated control and the gentamicin treatment alone only resulted in a 0.5 log reduction in the viable count for P. aeruginosa. The combined laser and gentamicin treatment, however, resulted in a synergistic effect and viability was reduced by 8 log's for P. aeruginosa PAO1.

  16. Fitness cost of antibiotic susceptibility during bacterial infection.

    PubMed

    Roux, Damien; Danilchanka, Olga; Guillard, Thomas; Cattoir, Vincent; Aschard, Hugues; Fu, Yang; Angoulvant, Francois; Messika, Jonathan; Ricard, Jean-Damien; Mekalanos, John J; Lory, Stephen; Pier, Gerald B; Skurnik, David

    2015-07-22

    Advances in high-throughput DNA sequencing allow for a comprehensive analysis of bacterial genes that contribute to virulence in a specific infectious setting. Such information can yield new insights that affect decisions on how to best manage major public health issues such as the threat posed by increasing antimicrobial drug resistance. Much of the focus has been on the consequences of the selective advantage conferred on drug-resistant strains during antibiotic therapy. It is thought that the genetic and phenotypic changes that confer resistance also result in concomitant reductions in in vivo fitness, virulence, and transmission. However, experimental validation of this accepted paradigm is modest. Using a saturated transposon library of Pseudomonas aeruginosa, we identified genes across many functional categories and operons that contributed to maximal in vivo fitness during lung infections in animal models. Genes that bestowed both intrinsic and acquired antibiotic resistance provided a positive in vivo fitness advantage to P. aeruginosa during infection. We confirmed these findings in the pathogenic bacteria Acinetobacter baumannii and Vibrio cholerae using murine and rabbit infection models, respectively. Our results show that efforts to confront the worldwide increase in antibiotic resistance might be exacerbated by fitness advantages that enhance virulence in drug-resistant microbes. PMID:26203082

  17. Prevalence and antibiotic susceptibility of Salmonella isolated from beef animal hides and carcasses.

    PubMed

    Bacon, R T; Sofos, J N; Belk, K E; Hyatt, D R; Smith, G C

    2002-02-01

    This study determined the prevalence of Salmonella on beef animal hides and carcasses and antimicrobial susceptibility profiles against a panel of 13 antibiotics. In each of the eight commercial packing facilities, of which five processed primarily heifers and steers and the remaining three processed primarily cows and bulls, hide and carcass sponge swab samples were obtained immediately before hide removal and before carcass chilling, respectively. Overall, prevalence of Salmonella on external surfaces (hides) of cattle was 15.4% (49 of 319), whereas prevalence after dehiding and other slaughtering/dressing processes, including the application of decontamination treatments, was, as expected, reduced (P < 0.05) to 1.3% (4 of 320) on carcass surfaces. From 53 total Salmonella-positive hide and carcass samples, 526 biochemically confirmed isolates were obtained to determine antimicrobial susceptibility profiles. Of 53 Salmonella-positive samples, individually, 24 (45.3%), 17 (32.1%), 17 (32.1%), 11 (20.8%), 8 (15.1%), 8 (15.1%), 8 (15.1%), 4 (7.5%), and 2 (3.8%) samples yielded at least one isolate resistant to amoxicillin/clavulanic acid, tetracycline, streptomycin, sulfonamides, ampicillin, ampicillin/sulbactam, chloramphenicol, gentamicin, and trimethoprim/sulfamethoxazole, respectively. None of the Salmonella-positive samples yielded an isolate resistant to ceftriaxone, ciprofloxacin, enrofloxacin, or levofloxacin. Although none of the samples yielded an isolate simultaneously resistant to three or four antimicrobials, a total of eight samples yielded at least one isolate resistant to five or more antimicrobials tested. Included among the 18 group B-positive samples were three samples that, individually, yielded at least one Salmonella Typhimurium var. Copenhagen DT104 isolate resistant to at least six antimicrobials tested. Results from this study support current prudent therapeutic and subtherapeutic antimicrobial use recommendations. PMID:11848559

  18. Association between clinical antibiotic resistance and susceptibility of Pseudomonas in the cystic fibrosis lung

    PubMed Central

    Jansen, Gunther; Mahrt, Niels; Tueffers, Leif; Barbosa, Camilo; Harjes, Malte; Adolph, Gernot; Friedrichs, Anette; Krenz-Weinreich, Annegret; Rosenstiel, Philip; Schulenburg, Hinrich

    2016-01-01

    Background and objectives: Cystic fibrosis patients suffer from chronic lung infections that require long-term antibiotic therapy. Pseudomonas readily evolve resistance, rendering antibiotics ineffective. In vitro experiments suggest that resistant bacteria may be treated by exploiting their collateral sensitivity to other antibiotics. Here, we investigate correlations of sensitivity and resistance profiles of Pseudomonas aeruginosa that naturally adapted to antibiotics in the cystic fibrosis lung. Methodology: Resistance profiles for 13 antibiotics were obtained using broth dilution, E-test and VITEK mass spectroscopy. Genetic variants were determined from whole-genome sequences and interrelationships among isolates were analyzed using 13 MLST loci. Result: Our study focused on 45 isolates from 13 patients under documented treatment with antibiotics. Forty percent of these were clinically resistant and 15% multi-drug resistant. Colistin resistance was found once, despite continuous colistin treatment and even though colistin resistance can readily evolve experimentally in the laboratory. Patients typically harbored multiple genetically and phenotypically distinct clones. However, genetically similar clones often had dissimilar resistance profiles. Isolates showed mutations in genes encoding cell wall synthesis, alginate production, efflux pumps and antibiotic modifying enzymes. Cross-resistance was commonly observed within antibiotic classes and between aminoglycosides and β-lactam antibiotics. No evidence was found for consistent phenotypic resistance to one antibiotic and sensitivity to another within one genotype. Conclusions and implications: Evidence supporting potential collateral sensitivity in clinical P. aeruginosa isolates remains equivocal. However, cross-resistance within antibiotic classes is common. Colistin therapy is promising since resistance to it was rare despite its intensive use in the studied patients. PMID:27193199

  19. Antibiotic susceptibilities of bacteria isolated within the oral flora of Florida blacktip sharks: guidance for empiric antibiotic therapy.

    PubMed

    Unger, Nathan R; Ritter, Erich; Borrego, Robert; Goodman, Jay; Osiyemi, Olayemi O

    2014-01-01

    Sharks possess a variety of pathogenic bacteria in their oral cavity that may potentially be transferred into humans during a bite. The aim of the presented study focused on the identification of the bacteria present in the mouths of live blacktip sharks, Carcharhinus limbatus, and the extent that these bacteria possess multi-drug resistance. Swabs were taken from the oral cavity of nineteen live blacktip sharks, which were subsequently released. The average fork length was 146 cm (±11), suggesting the blacktip sharks were mature adults at least 8 years old. All swabs underwent standard microbiological work-up with identification of organisms and reporting of antibiotic susceptibilities using an automated microbiology system. The oral samples revealed an average of 2.72 (±1.4) bacterial isolates per shark. Gram-negative bacteria, making up 61% of all bacterial isolates, were significantly (p<0.001) more common than gram-positive bacteria (39%). The most common organisms were Vibrio spp. (28%), various coagulase-negative Staphylococcus spp. (16%), and Pasteurella spp. (12%). The overall resistance rate was 12% for all antibiotics tested with nearly 43% of bacteria resistant to at least one antibiotic. Multi-drug resistance was seen in 4% of bacteria. No association between shark gender or fork length with bacterial density or antibiotic resistance was observed. Antibiotics with the highest overall susceptibility rates included fluoroquinolones, 3rd generation cephalosporins and sulfamethoxazole/trimethoprim. Recommended empiric antimicrobial therapy for adult blacktip shark bites should encompass either a fluoroquinolone or combination of a 3rd generation cephalosporin plus doxycycline. PMID:25110948

  20. Antibiotic Susceptibilities of Bacteria Isolated within the Oral Flora of Florida Blacktip Sharks: Guidance for Empiric Antibiotic Therapy

    PubMed Central

    Unger, Nathan R.; Ritter, Erich; Borrego, Robert; Goodman, Jay; Osiyemi, Olayemi O.

    2014-01-01

    Sharks possess a variety of pathogenic bacteria in their oral cavity that may potentially be transferred into humans during a bite. The aim of the presented study focused on the identification of the bacteria present in the mouths of live blacktip sharks, Carcharhinus limbatus, and the extent that these bacteria possess multi-drug resistance. Swabs were taken from the oral cavity of nineteen live blacktip sharks, which were subsequently released. The average fork length was 146 cm (±11), suggesting the blacktip sharks were mature adults at least 8 years old. All swabs underwent standard microbiological work-up with identification of organisms and reporting of antibiotic susceptibilities using an automated microbiology system. The oral samples revealed an average of 2.72 (±1.4) bacterial isolates per shark. Gram-negative bacteria, making up 61% of all bacterial isolates, were significantly (p<0.001) more common than gram-positive bacteria (39%). The most common organisms were Vibrio spp. (28%), various coagulase-negative Staphylococcus spp. (16%), and Pasteurella spp. (12%). The overall resistance rate was 12% for all antibiotics tested with nearly 43% of bacteria resistant to at least one antibiotic. Multi-drug resistance was seen in 4% of bacteria. No association between shark gender or fork length with bacterial density or antibiotic resistance was observed. Antibiotics with the highest overall susceptibility rates included fluoroquinolones, 3rd generation cephalosporins and sulfamethoxazole/trimethoprim. Recommended empiric antimicrobial therapy for adult blacktip shark bites should encompass either a fluoroquinolone or combination of a 3rd generation cephalosporin plus doxycycline. PMID:25110948

  1. Changes in antibiotic susceptability of Escherichia coli isolated from steers exposed to antibiotics during the early feeding period.

    PubMed

    Coe, Paul H; Grooms, Daniel L; Metz, Ken; Holland, Robert E

    2008-01-01

    The influence of therapeutic choices on antibiotic resistance of intestinal bacteria may have food safety consequences. Changes in antibiotic susceptibility of Escherichia coli to antibiotics currently approved for prevention and treatment of bovine respiratory disease were evaluated in 260 feedlot steers. Susceptibilities to antimicrobial compounds were compared among three treatment groups at three times between arrival at the feedlot and harvest to assess changes over the course of the feeding period. No significant change was found in the resistance of E. coli to tilmicosin, florfenicol, and enrofloxacin, which were used to prevent and treat respiratory disease in this study. Despite an absence of exposure to ampicillin and ceftiofur, a significant increase in resistance was observed for these two antimicrobial drugs that declined by the end of the feeding period. In this study, use of approved antimicrobials early in the feeding period for the prevention and treatment of bovine respiratory disease had little effect on antimicrobial resistance of E. coli isolated from cattle near the time of slaughter. PMID:19003784

  2. Mechanisms that may account for differential antibiotic susceptibilities among Coxiella burnetii isolates.

    PubMed Central

    Yeaman, M R; Baca, O G

    1991-01-01

    The Nine Mile, S Q217, and Priscilla isolates, representative of the three major genetic groups of Coxiella burnetii, are known to differ in their susceptibilities to antibiotics. Mechanisms potentially responsible for these differences were investigated. Accumulation of antibiotics by infected L929 cells and purified isolates was measured. In addition, C. burnetii plasmid-transformed Escherichia coli HB101 cells were used to study the possibility that different C. burnetii plasmids are responsible for disparate antibiotic susceptibilities of the isolates. L929 cells recently or persistently infected with the Priscilla isolate exhibited a significantly reduced accumulation of [3H]tetracycline as compared with that in L929 cells infected with either the Nine Mile or S Q217 isolates; accumulation of this drug was greater in cells recently infected each isolate. In contrast, L929 cells recently or persistently infected with the different isolates accumulated [3H]norfloxacin to an equivalent extent. [3H]tetracycline accumulation was approximately the same among the purified isolates. However, as measured by both scintillation and spectrofluorometry, norfloxacin accumulation was significantly diminished in the purified Priscilla isolate. pH had no apparent effect upon isolate permeabilities. The presence of C. burnetii QpH1 or QpRS plasmids did not alter the antibiotic susceptibility of E. coli. Collectively, these results indicate that differential susceptibilities to tetracyclines or fluoroquinolones in C. burnetii isolates may be the result of distinct mechanisms involving altered host-cell (tetracyclines) or isolate-specific (fluoroquinolones) permeabilities. PMID:1854176

  3. Changing susceptibility of Pseudomonas aeruginosa isolates from cystic fibrosis patients with the clinical use of newer antibiotics.

    PubMed Central

    Bosso, J A; Allen, J E; Matsen, J M

    1989-01-01

    To detect a change in antibiotic susceptibility patterns in Pseudomonas aeruginosa isolates upon the introduction and clinical use of ciprofloxacin, aztreonam, and ceftazidime, MICs for clinical isolates collected before introduction of the antibiotics, during early clinical use, and later were determined for these and seven other antipseudomonal antibiotics. Concomitant resistance to two or more antibiotics was also studied. Over the three study periods, rates of susceptibility to 9 of the 10 antibiotics decreased. The largest decrease occurred with ceftazidime. Analysis of subsets of isolates from patients treated with ciprofloxacin or aztreonam also showed declining susceptibility to the latter but a stabilization of susceptibility to the former after an initial decline. Concomitant resistance within and among antibiotic classes was common. PMID:2499252

  4. MBT-ASTRA: A suitable tool for fast antibiotic susceptibility testing?

    PubMed

    Sparbier, Katrin; Schubert, Sören; Kostrzewa, Markus

    2016-07-15

    The increasing resistance to antibiotics is an urgent health care problem. Detection of resistant microorganisms is the pre-requisite for initiating an adequate therapy and implementing respective hygiene measures. Depending on the species and the method employed for analysis, the time to result of antibiotic resistance testing ranges between five and 24h. As MALDI-TOF MS has become an established tool for the fast species identification in microbiological laboratories a time gap between the results of species identification and the information about antibiotic susceptibility arises. Here, we present a semi-quantitative MALDI-TOF MS-based approach for the detection of resistance in different species against different antibiotics. PMID:26804565

  5. Antibiotic resistance profiles among mesophilic aerobic bacteria in Nigerian chicken litter and associated antibiotic resistance genes1.

    PubMed

    Olonitola, Olayeni Stephen; Fahrenfeld, Nicole; Pruden, Amy

    2015-05-01

    The effect of global antibiotic use practices in livestock on the emergence of antibiotic resistant pathogens is poorly understood. There is a paucity of data among African nations, which suffer from high rates of antibiotic resistant infections among the human population. Escherichia (29.5%), Staphylococcus (15.8%), and Proteus (15.79%) were the dominant bacterial genera isolated from chicken litter from four different farms in Zaria, Nigeria, all of which contain human pathogenic members. Escherichia isolates were uniformly susceptible to augmentin and cefuroxime, but resistant to sulfamethoxazole (54.5%), ampicillin (22.7%), ciprofloxacin (18.2%), cephalothin (13.6%) and gentamicin (13.6%). Staphylococcus isolates were susceptible to ciprofloxacin, gentamicin, and sulfamethoxazole, but resistant to tetracycline (86.7%), erythromycin (80%), clindamycin (60%), and penicillin (33.3%). Many of the isolates (65.4%) were resistant to multiple antibiotics, with a multiple antibiotic resistance index (MARI) ≥ 0.2. sul1, sul2, and vanA were the most commonly detected antibiotic resistance genes among the isolates. Chicken litter associated with antibiotic use and farming practices in Nigeria could be a public health concern given that the antibiotic resistant patterns among genera containing pathogens indicate the potential for antibiotic treatment failure. However, the MARI values were generally lower than reported for Escherichia coli from intensive poultry operations in industrial nations. PMID:25725076

  6. Escherichia coli adhesion, biofilm development and antibiotic susceptibility on biomedical materials.

    PubMed

    Gomes, L C; Silva, L N; Simões, M; Melo, L F; Mergulhão, F J

    2015-04-01

    The aim of this work was to test materials typically used in the construction of medical devices regarding their influence in the initial adhesion, biofilm development and antibiotic susceptibility of Escherichia coli biofilms. Adhesion and biofilm development was monitored in 12-well microtiter plates containing coupons of different biomedical materials--silicone (SIL), stainless steel (SS) and polyvinyl chloride (PVC)--and glass (GLA) as control. The susceptibility of biofilms to ciprofloxacin and ampicillin was assessed, and the antibiotic effect in cell morphology was observed by scanning electron microscopy. The surface hydrophobicity of the bacterial strain and materials was also evaluated from contact angle measurements. Surface hydrophobicity was related with initial E. coli adhesion and subsequent biofilm development. Hydrophobic materials, such as SIL, SS, and PVC, showed higher bacterial colonization than the hydrophilic GLA. Silicone was the surface with the greatest number of adhered cells and the biofilms formed on this material were also less susceptible to both antibiotics. It was found that different antibiotics induced different levels of elongation on E. coli sessile cells. Results revealed that, by affecting the initial adhesion, the surface properties of a given material can modulate biofilm buildup and interfere with the outcome of antimicrobial therapy. These findings raise the possibility of fine-tuning surface properties as a strategy to reach higher therapeutic efficacy. PMID:25044887

  7. Selective pharmacologic inhibition of a PASTA kinase increases Listeria monocytogenes susceptibility to β-lactam antibiotics.

    PubMed

    Pensinger, Daniel A; Aliota, Matthew T; Schaenzer, Adam J; Boldon, Kyle M; Ansari, Israr-ul H; Vincent, William J B; Knight, Benjamin; Reniere, Michelle L; Striker, Rob; Sauer, John-Demian

    2014-08-01

    While β-lactam antibiotics are a critical part of the antimicrobial arsenal, they are frequently compromised by various resistance mechanisms, including changes in penicillin binding proteins of the bacterial cell wall. Genetic deletion of the penicillin binding protein and serine/threonine kinase-associated protein (PASTA) kinase in methicillin-resistant Staphylococcus aureus (MRSA) has been shown to restore β-lactam susceptibility. However, the mechanism remains unclear, and whether pharmacologic inhibition would have the same effect is unknown. In this study, we found that deletion or pharmacologic inhibition of the PASTA kinase in Listeria monocytogenes by the nonselective kinase inhibitor staurosporine results in enhanced susceptibility to both aminopenicillin and cephalosporin antibiotics. Resistance to vancomycin, another class of cell wall synthesis inhibitors, or antibiotics that inhibit protein synthesis was unaffected by staurosporine treatment. Phosphorylation assays with purified kinases revealed that staurosporine selectively inhibited the PASTA kinase of L. monocytogenes (PrkA). Importantly, staurosporine did not inhibit a L. monocytogenes kinase without a PASTA domain (Lmo0618) or the PASTA kinase from MRSA (Stk1). Finally, inhibition of PrkA with a more selective kinase inhibitor, AZD5438, similarly led to sensitization of L. monocytogenes to β-lactam antibiotics. Overall, these results suggest that pharmacologic targeting of PASTA kinases can increase the efficacy of β-lactam antibiotics. PMID:24867981

  8. Selective Pharmacologic Inhibition of a PASTA Kinase Increases Listeria monocytogenes Susceptibility to β-Lactam Antibiotics

    PubMed Central

    Pensinger, Daniel A.; Aliota, Matthew T.; Schaenzer, Adam J.; Boldon, Kyle M.; Ansari, Israr-ul H.; Vincent, William J. B.; Knight, Benjamin; Reniere, Michelle L.; Striker, Rob

    2014-01-01

    While β-lactam antibiotics are a critical part of the antimicrobial arsenal, they are frequently compromised by various resistance mechanisms, including changes in penicillin binding proteins of the bacterial cell wall. Genetic deletion of the penicillin binding protein and serine/threonine kinase-associated protein (PASTA) kinase in methicillin-resistant Staphylococcus aureus (MRSA) has been shown to restore β-lactam susceptibility. However, the mechanism remains unclear, and whether pharmacologic inhibition would have the same effect is unknown. In this study, we found that deletion or pharmacologic inhibition of the PASTA kinase in Listeria monocytogenes by the nonselective kinase inhibitor staurosporine results in enhanced susceptibility to both aminopenicillin and cephalosporin antibiotics. Resistance to vancomycin, another class of cell wall synthesis inhibitors, or antibiotics that inhibit protein synthesis was unaffected by staurosporine treatment. Phosphorylation assays with purified kinases revealed that staurosporine selectively inhibited the PASTA kinase of L. monocytogenes (PrkA). Importantly, staurosporine did not inhibit a L. monocytogenes kinase without a PASTA domain (Lmo0618) or the PASTA kinase from MRSA (Stk1). Finally, inhibition of PrkA with a more selective kinase inhibitor, AZD5438, similarly led to sensitization of L. monocytogenes to β-lactam antibiotics. Overall, these results suggest that pharmacologic targeting of PASTA kinases can increase the efficacy of β-lactam antibiotics. PMID:24867981

  9. Polyphenolic extract from maple syrup potentiates antibiotic susceptibility and reduces biofilm formation of pathogenic bacteria.

    PubMed

    Maisuria, Vimal B; Hosseinidoust, Zeinab; Tufenkji, Nathalie

    2015-06-01

    Phenolic compounds are believed to be promising candidates as complementary therapeutics. Maple syrup, prepared by concentrating the sap from the North American maple tree, is a rich source of natural and process-derived phenolic compounds. In this work, we report the antimicrobial activity of a phenolic-rich maple syrup extract (PRMSE). PRMSE exhibited antimicrobial activity as well as strong synergistic interaction with selected antibiotics against Gram-negative clinical strains of Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa. Among the phenolic constituents of PRMSE, catechol exhibited strong synergy with antibiotics as well as with other phenolic components of PRMSE against bacterial growth. At sublethal concentrations, PRMSE and catechol efficiently reduced biofilm formation and increased the susceptibility of bacterial biofilms to antibiotics. In an effort to elucidate the mechanism for the observed synergy with antibiotics, PRMSE was found to increase outer membrane permeability of all bacterial strains and effectively inhibit efflux pump activity. Furthermore, transcriptome analysis revealed that PRMSE significantly repressed multiple-drug resistance genes as well as genes associated with motility, adhesion, biofilm formation, and virulence. Overall, this study provides a proof of concept and starting point for investigating the molecular mechanism of the reported increase in bacterial antibiotic susceptibility in the presence of PRMSE. PMID:25819960

  10. Saponins increase susceptibility of vancomycin-resistant enterococci to antibiotic compounds

    PubMed Central

    Heimesaat, Markus M.; Fischer, André; Bereswill, Stefan; Melzig, Matthias F.

    2014-01-01

    The resistance of commensal bacteria to first and second line antibiotics has reached an alarming level in many parts of the world and endangers the effective treatment of infectious diseases. In this study, the influence of the plant-derived natural saponins glycyrrhizic acid, β-aescin, α-hederin, hederacoside C, and primulic acid 1 on the susceptibility of vancomycin-resistant enterococci (VRE) against antibiotics of clinical relevance was investigated in 20 clinical isolates. Furthermore, the antibacterial properties of saponins under study against VRE were determined in vitro. Results reveal that the susceptibility of VRE against gentamicin, teicoplanin, and daptomycin was enhanced in the presence of the saponin glycyrrhizic acid. Most importantly, glycyrrhizic acid (1 mg/ml) diminished the minimal inhibitory concentration (MIC) of gentamicin in gentamicin low-level intrinsic resistant VRE from 2 – >8 mg/l to ≤ 0.125–1 mg/l. The adding of β-aescin, α-hederin, hederacoside C, and primulic acid 1 to the antibiotics under study showed, compared to glycyrrhizic acid, less influence on the antibiotic potency. Only glycyrrhizic acid (1 mg/ml) and α‑hederin (0.2 mg/ml) showed weak antibacterial properties against the clinical isolates. Our study points towards a therapeutic potential of saponins in the coapplication with antibiotics for bacterial infections. PMID:25544893

  11. Saponins increase susceptibility of vancomycin-resistant enterococci to antibiotic compounds.

    PubMed

    Schmidt, Sebastian; Heimesaat, Markus M; Fischer, André; Bereswill, Stefan; Melzig, Matthias F

    2014-12-01

    The resistance of commensal bacteria to first and second line antibiotics has reached an alarming level in many parts of the world and endangers the effective treatment of infectious diseases. In this study, the influence of the plant-derived natural saponins glycyrrhizic acid, β-aescin, α-hederin, hederacoside C, and primulic acid 1 on the susceptibility of vancomycin-resistant enterococci (VRE) against antibiotics of clinical relevance was investigated in 20 clinical isolates. Furthermore, the antibacterial properties of saponins under study against VRE were determined in vitro. Results reveal that the susceptibility of VRE against gentamicin, teicoplanin, and daptomycin was enhanced in the presence of the saponin glycyrrhizic acid. Most importantly, glycyrrhizic acid (1 mg/ml) diminished the minimal inhibitory concentration (MIC) of gentamicin in gentamicin low-level intrinsic resistant VRE from 2 - >8 mg/l to ≤ 0.125-1 mg/l. The adding of β-aescin, α-hederin, hederacoside C, and primulic acid 1 to the antibiotics under study showed, compared to glycyrrhizic acid, less influence on the antibiotic potency. Only glycyrrhizic acid (1 mg/ml) and α‑hederin (0.2 mg/ml) showed weak antibacterial properties against the clinical isolates. Our study points towards a therapeutic potential of saponins in the coapplication with antibiotics for bacterial infections. PMID:25544893

  12. Polyphenolic Extract from Maple Syrup Potentiates Antibiotic Susceptibility and Reduces Biofilm Formation of Pathogenic Bacteria

    PubMed Central

    Maisuria, Vimal B.; Hosseinidoust, Zeinab

    2015-01-01

    Phenolic compounds are believed to be promising candidates as complementary therapeutics. Maple syrup, prepared by concentrating the sap from the North American maple tree, is a rich source of natural and process-derived phenolic compounds. In this work, we report the antimicrobial activity of a phenolic-rich maple syrup extract (PRMSE). PRMSE exhibited antimicrobial activity as well as strong synergistic interaction with selected antibiotics against Gram-negative clinical strains of Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa. Among the phenolic constituents of PRMSE, catechol exhibited strong synergy with antibiotics as well as with other phenolic components of PRMSE against bacterial growth. At sublethal concentrations, PRMSE and catechol efficiently reduced biofilm formation and increased the susceptibility of bacterial biofilms to antibiotics. In an effort to elucidate the mechanism for the observed synergy with antibiotics, PRMSE was found to increase outer membrane permeability of all bacterial strains and effectively inhibit efflux pump activity. Furthermore, transcriptome analysis revealed that PRMSE significantly repressed multiple-drug resistance genes as well as genes associated with motility, adhesion, biofilm formation, and virulence. Overall, this study provides a proof of concept and starting point for investigating the molecular mechanism of the reported increase in bacterial antibiotic susceptibility in the presence of PRMSE. PMID:25819960

  13. Rapid, low-cost fluorescent assay of β-lactamase-derived antibiotic resistance and related antibiotic susceptibility

    NASA Astrophysics Data System (ADS)

    Erdem, S. Sibel; Khan, Shazia; Palanisami, Akilan; Hasan, Tayyaba

    2014-10-01

    Antibiotic resistance (AR) is increasingly prevalent in low and middle income countries (LMICs), but the extent of the problem is poorly understood. This lack of knowledge is a critical deficiency, leaving local health authorities essentially blind to AR outbreaks and crippling their ability to provide effective treatment guidelines. The crux of the problem is the lack of microbiology laboratory capacity available in LMICs. To address this unmet need, we demonstrate a rapid and simple test of β-lactamase resistance (the most common form of AR) that uses a modified β-lactam structure decorated with two fluorophores quenched due to their close proximity. When the β-lactam core is cleaved by β-lactamase, the fluorophores dequench, allowing assay speeds of 20 min to be obtained with a simple, streamlined protocol. Furthermore, by testing in competition with antibiotics, the β-lactamase-associated antibiotic susceptibility can also be extracted. This assay can be easily implemented into standard lab work flows to provide near real-time information of β-lactamase resistance, both for epidemiological purposes as well as individualized patient care.

  14. Rapid, low-cost fluorescent assay of β-lactamase-derived antibiotic resistance and related antibiotic susceptibility

    PubMed Central

    Erdem, S. Sibel; Khan, Shazia; Palanisami, Akilan; Hasan, Tayyaba

    2014-01-01

    Abstract. Antibiotic resistance (AR) is increasingly prevalent in low and middle income countries (LMICs), but the extent of the problem is poorly understood. This lack of knowledge is a critical deficiency, leaving local health authorities essentially blind to AR outbreaks and crippling their ability to provide effective treatment guidelines. The crux of the problem is the lack of microbiology laboratory capacity available in LMICs. To address this unmet need, we demonstrate a rapid and simple test of β-lactamase resistance (the most common form of AR) that uses a modified β-lactam structure decorated with two fluorophores quenched due to their close proximity. When the β-lactam core is cleaved by β-lactamase, the fluorophores dequench, allowing assay speeds of 20 min to be obtained with a simple, streamlined protocol. Furthermore, by testing in competition with antibiotics, the β-lactamase-associated antibiotic susceptibility can also be extracted. This assay can be easily implemented into standard lab work flows to provide near real-time information of β-lactamase resistance, both for epidemiological purposes as well as individualized patient care. PMID:25321396

  15. Effects of osmotic pressure, acid, or cold stresses on antibiotic susceptibility of Listeria monocytogenes.

    PubMed

    Al-Nabulsi, Anas A; Osaili, Tareq M; Shaker, Reyad R; Olaimat, Amin N; Jaradat, Ziad W; Zain Elabedeen, Noor A; Holley, Richard A

    2015-04-01

    Prevalence of antibiotic resistance of Listeria monocytogenes isolated from a variety of foods has increased in many countries. L. monocytogenes has many physiological adaptations that enable survival under a wide range of environmental stresses. The objective of this study was to evaluate effects of osmotic (2, 4, 6, 12% NaC), pH (6, 5.5, 5.0) and cold (4 °C) stresses on susceptibility of three isolates of L. monocytogenes towards different antibiotics. The minimal inhibitory concentrations (MICs) of tested antibiotics against unstressed (control), stressed or post-stressed L. monocytogenes isolates (an ATCC strain and a meat and dairy isolate) were determined using the broth microdilution method. Unstressed cells of L. monocytogenes were sensitive to all tested antibiotics. In general, when L. monocytogenes cells were exposed to salt, cold and pH stresses, their antibiotic resistance increased as salt concentration increased to 6 or 12%, as pH was reduced to pH 5 or as temperature was decreased to 10 °C. Results showed that both meat and dairy isolates were more resistant than the ATCC reference strain. Use of sub-lethal stresses in food preservation systems may stimulate antibiotic resistance responses in L. monocytogenes strains. PMID:25475279

  16. Inhibition of LpxC Increases Antibiotic Susceptibility in Acinetobacter baumannii.

    PubMed

    García-Quintanilla, Meritxell; Caro-Vega, José M; Pulido, Marina R; Moreno-Martínez, Patricia; Pachón, Jerónimo; McConnell, Michael J

    2016-08-01

    LpxC inhibitors have generally shown poor in vitro activity against Acinetobacter baumannii We show that the LpxC inhibitor PF-5081090 inhibits lipid A biosynthesis, as determined by silver staining and measurements of endotoxin levels, and significantly increases cell permeability. The presence of PF-5081090 at 32 mg/liter increased susceptibility to rifampin, vancomycin, azithromycin, imipenem, and amikacin but had no effect on susceptibility to ciprofloxacin and tigecycline. Potentiating existing antibiotics with LpxC inhibitors may represent an alternative treatment strategy for multidrug-resistant A. baumannii. PMID:27270288

  17. Antibiotic Susceptibility Patterns of Pseudomonas Corneal Ulcers in Contact Lens Wearers

    PubMed Central

    Mohammadpour, Mehrdad; Mohajernezhadfard, Zahra; Khodabande, Alireza; Vahedi, Payman

    2011-01-01

    Purpose: To evaluate the resistance or susceptibility of Pseudomonas aeruginosa, the most common pathogen in contact lens keratitis and corneal ulcer, to different antibiotic regimens. Materials and Methods: This cross-sectional study included all patients with recently diagnosed contact lens corneal ulcer whose culture results were positive for P. aeruginosa, from March 2009 to March 2010. The empirical antibiotic therapy was changed to appropriate antibiotics according to the culture results, provided that satisfactory clinical improvement was not achieved with the initial antibiotic regimen. The overall sensitivity or resistance of P. aeruginosa to the most commonly used antibiotics was assessed based on the results of the antibiograms. Results: Fifty-two patients (43 females and 9 males) were included. Forty-five patients (86%) were wearing cosmetic contact lenses, while 7 patients (14%) were using therapeutic contact lenses. Thirty-nine patients (75%) were hospitalized and13 patients (25%) were followed up through an outpatient clinic. Thirty patients (58%) had central ulcers, whereas 22 patients (42%) had peripheral ulcers. Twelve patients (23%) had hypopyon in their first exam. The mean time to diagnose the ulcer after the last time wearing was 2 days (range: 12 hours to 5 days). AMT was required for 10 patients (19%). Based on the antibiograms, PA was shown to be sensitive in 100% of cases to ceftazidime and ciprofloxacin. Amikacin, imipenem, and gentamicin were the second most effective antibiotics. Conclusion: P. aeruginosa was highly sensitive to ceftazidime, ciprofloxacin, and amikacin. All cases were resistant to cefazolin. Resistance to multiple antibiotics might be a significant concern in patients with corneal ulcers. In referral centers dealing with corneal ulcers, the initial antibiotic regimens should be changed from time to time to prevent this phenomenon. PMID:21887079

  18. Short communication: N-Acetylcysteine-mediated modulation of antibiotic susceptibility of bovine mastitis pathogens.

    PubMed

    Yang, F; Liu, L H; Li, X P; Luo, J Y; Zhang, Z; Yan, Z T; Zhang, S D; Li, H S

    2016-06-01

    The aim of this study was to investigate the effects of N-acetylcysteine (NAC) on antibiotic susceptibility of bovine mastitis pathogens including Staphylococcus aureus, Streptococcus dysgalactiae, Escherichia coli, and Streptococcus agalactiae. Minimum inhibitory concentrations (MIC) were tested by the agar-based E-test method. The presence of 10mM NAC reduced the MIC of penicillin and ampicillin but enhanced the MIC of erythromycin and ciprofloxacin for all of the strains. In addition, NAC-mediated modulation of MIC of kanamycin, tetracycline, and vancomycin was diverse, depending on the target bacterial pathogen and antibiotic being used. The results suggest that NAC is an important modulator of antibiotic activity against the major bovine mastitis pathogens. PMID:27016837

  19. Triazole-Linked Glycolipids Enhance the Susceptibility of MRSA to β-Lactam Antibiotics

    PubMed Central

    2015-01-01

    We show here that a series of triazolyl glycolipid derivatives modularly synthesized by a “click” reaction have the ability to increase the susceptibility of a drug-resistant bacterium to β-lactam antibiotics. We determine that the glycolipids can suppress the minimal inhibitory concentration of a number of ineffective β-lactams, upward of 256-fold, for methicillin-resistant Staphylococuss aureus (MRSA). The mechanism of action has been preliminarily probed and discussed. PMID:26191368

  20. Triazole-Linked Glycolipids Enhance the Susceptibility of MRSA to β-Lactam Antibiotics.

    PubMed

    Hu, Xi-Le; Li, Dan; Shao, Lei; Dong, Xiaojing; He, Xiao-Peng; Chen, Guo-Rong; Chen, Daijie

    2015-07-01

    We show here that a series of triazolyl glycolipid derivatives modularly synthesized by a "click" reaction have the ability to increase the susceptibility of a drug-resistant bacterium to β-lactam antibiotics. We determine that the glycolipids can suppress the minimal inhibitory concentration of a number of ineffective β-lactams, upward of 256-fold, for methicillin-resistant Staphylococuss aureus (MRSA). The mechanism of action has been preliminarily probed and discussed. PMID:26191368

  1. Antibiotic susceptibility of respiratory pathogens recently isolated in Italy: focus on cefditoren.

    PubMed

    Tempera, G; Furneri, P M; Carlone, N A; Cocuzza, C; Rigoli, R; Musumeci, R; Pilloni, A P; Prenna, M; Tufano, M A; Tullio, V; Vitali, L A; Nicoletti, G

    2010-06-01

    The aim of this study was to evaluate the in vitro antibiotic susceptibility of respiratory pathogens recently isolated in Italy to commonly used antibiotics including cefditoren. Six clinical microbiological laboratories collected, between January and September 2009, a total of 2,510 respiratory pathogens from subjects with community-acquired respiratory tract infections (CARTI). Ceftditoren, out of all the beta-lactams studied, had the lowest MIC(90 )against 965 strains of Streptococcus pneumoniae examined, followed by cefotaxime and ceftriaxone (2% resistance in penicillin-resistant S. pneumoniae (PRSP)). Against 470 Haemophilus influenzae , independently of their production of beta-lactamases or ampicillin resistance, cefditoren was the oral cephalosporin with the best in vitro activity, comparable to that of the injectable cephalosporins and levofloxacin. Higher MIC(90)s were found for the macrolides (4 - 16 mg/l) and cefaclor (4 - 32 mg/l). As was foreseeable, Streptococcus pyogenes (225 strains) was uniformly sensitive to all the beta-lactam antibiotics, but the elevated MIC(90 )values reduced (<75%) susceptibility of this pathogen to macrolides. Beta-lactamase-negative Moraxella catarrhalis (100 strains) had reduced susceptibility only to the macrolides, while the 250 beta-lactamase-producing strains also had reduced susceptibility to cefuroxime. Levofloxacin showed the lowest MIC(50)/MIC(90 )values in the producing strains, whereas cefditoren, cefotaxime and ceftriaxone in the non-producers. As regards the enterobacteriaceae, cefditoren and levofloxacin had the lowest MIC(90)s against Klebsiella pneumoniae. Cefditoren and the third-generation injectable cephalosporins had the lowest MIC(90)s against Escherichia coli (100% susceptibility) while levofloxacin was less active (86% susceptibility).In conclusion, cefditoren's wide spectrum and high intrinsic activity, as well as its capacity to overcome most of the resistance that has become consolidated in some

  2. Regulatory Mutations Impacting Antibiotic Susceptibility in an Established Staphylococcus aureus Biofilm

    PubMed Central

    Beenken, Karen E.; Lantz, Tamara L.; Meeker, Daniel G.; Lynn, William B.; Mills, Weston B.; Spencer, Horace J.

    2016-01-01

    We previously determined the extent to which mutations of different Staphylococcus aureus regulatory loci impact biofilm formation as assessed under in vitro conditions. Here we extend these studies to determine the extent to which those regulatory loci that had the greatest effect on biofilm formation also impact antibiotic susceptibility. The experiments were done under in vitro and in vivo conditions using two clinical isolates of S. aureus (LAC and UAMS-1) and two functionally diverse antibiotics (daptomycin and ceftaroline). Mutation of the staphylococcal accessory regulator (sarA) or sigB was found to significantly increase susceptibilities to both antibiotics and in both strains in a manner that could not be explained by changes in the MICs. The impact of a mutation in sarA was comparable to that of a mutation in sigB and greater than the impact observed with any other mutant. These results suggest that therapeutic strategies targeting sarA and/or sigB have the greatest potential to facilitate the ability to overcome the intrinsic antibiotic resistance that defines S. aureus biofilm-associated infections. PMID:26824954

  3. Regulatory Mutations Impacting Antibiotic Susceptibility in an Established Staphylococcus aureus Biofilm.

    PubMed

    Atwood, Danielle N; Beenken, Karen E; Lantz, Tamara L; Meeker, Daniel G; Lynn, William B; Mills, Weston B; Spencer, Horace J; Smeltzer, Mark S

    2016-03-01

    We previously determined the extent to which mutations of different Staphylococcus aureus regulatory loci impact biofilm formation as assessed under in vitro conditions. Here we extend these studies to determine the extent to which those regulatory loci that had the greatest effect on biofilm formation also impact antibiotic susceptibility. The experiments were done under in vitro and in vivo conditions using two clinical isolates of S. aureus (LAC and UAMS-1) and two functionally diverse antibiotics (daptomycin and ceftaroline). Mutation of the staphylococcal accessory regulator (sarA) or sigB was found to significantly increase susceptibilities to both antibiotics and in both strains in a manner that could not be explained by changes in the MICs. The impact of a mutation in sarA was comparable to that of a mutation in sigB and greater than the impact observed with any other mutant. These results suggest that therapeutic strategies targeting sarA and/or sigB have the greatest potential to facilitate the ability to overcome the intrinsic antibiotic resistance that defines S. aureus biofilm-associated infections. PMID:26824954

  4. Isolation and Antibiotic Susceptibility of the Microorganisms Isolated from Diabetic Foot Infections in Nemazee Hospital, Southern Iran

    PubMed Central

    Anvarinejad, Mojtaba; Pouladfar, Gholamreza; Japoni, Aziz; Bolandparvaz, Shahram; Satiary, Zeinab; Abbasi, Pejman; Mardaneh, Jalal

    2015-01-01

    Background. Diabetic foot infections (DFIs) are a major public health issue and identification of the microorganisms causing such polymicrobial infections is useful to find out appropriate antibiotic therapy. Meanwhile, many reports have shown antibiotic resistance rising dramatically. In the present study, we sought to determine the prevalence of microorganisms detected on culture in complicated DFIs in hospitalized patients and their antibiotic sensitivity profiles. Methods. A cross-sectional study was conducted for a period of 24 months from 2012 to 2014 in Nemazee Hospital, Shiraz, Iran. The demographic and clinical features of the patients were obtained. Antimicrobial susceptibility testing to different agents was carried out using the disc diffusion method. Results. During this period, 122 aerobic microorganisms were isolated from DFIs. Among Gram-positive and Gram-negative bacteria, Staphylococcus spp. and E. coli were the most frequent organisms isolated, respectively. Of the isolates, 91% were multidrug while 78% of S. aureus isolates were methicillin resistant. 53% of Gram-negative bacteria were positive for extended-spectrum β-lactamase. Conclusion. Given the involvement of different microorganisms and emergence of multidrug resistant strains, clinicians are advised to consider culture before initiation of empirical therapy. PMID:26843987

  5. Antibiotic Susceptibility Pattern of Aerobic and Anaerobic Bacteria Isolated From Surgical Site Infection of Hospitalized Patients

    PubMed Central

    Akhi, Mohammad Taghi; Ghotaslou, Reza; Beheshtirouy, Samad; Asgharzadeh, Mohammad; Pirzadeh, Tahereh; Asghari, Babak; Alizadeh, Naser; Toloue Ostadgavahi, Ali; Sorayaei Somesaraei, Vida; Memar, Mohammad Yousef

    2015-01-01

    Background: Surgical Site Infections (SSIs) are infections of incision or deep tissue at operation sites. These infections prolong hospitalization, delay wound healing, and increase the overall cost and morbidity. Objectives: This study aimed to investigate anaerobic and aerobic bacteria prevalence in surgical site infections and determinate antibiotic susceptibility pattern in these isolates. Materials and Methods: One hundred SSIs specimens were obtained by needle aspiration from purulent material in depth of infected site. These specimens were cultured and incubated in both aerobic and anaerobic condition. For detection of antibiotic susceptibility pattern in aerobic and anaerobic bacteria, we used disk diffusion, agar dilution, and E-test methods. Results: A total of 194 bacterial strains were isolated from 100 samples of surgical sites. Predominant aerobic and facultative anaerobic bacteria isolated from these specimens were the members of Enterobacteriaceae family (66, 34.03%) followed by Pseudomonas aeruginosa (26, 13.4%), Staphylococcus aureus (24, 12.37%), Acinetobacter spp. (18, 9.28%), Enterococcus spp. (16, 8.24%), coagulase negative Staphylococcus spp. (14, 7.22%) and nonhemolytic streptococci (2, 1.03%). Bacteroides fragilis (26, 13.4%), and Clostridium perfringens (2, 1.03%) were isolated as anaerobic bacteria. The most resistant bacteria among anaerobic isolates were B. fragilis. All Gram-positive isolates were susceptible to vancomycin and linezolid while most of Enterobacteriaceae showed sensitivity to imipenem. Conclusions: Most SSIs specimens were polymicrobial and predominant anaerobic isolate was B. fragilis. Isolated aerobic and anaerobic strains showed high level of resistance to antibiotics. PMID:26421133

  6. Characterization of Antibiotic Resistance Profiles of Ocular Enterobacteriaceae Isolates.

    PubMed

    Paul-Satyaseela, Maneesh; Murali, Sowmiya; Thirunavukkarasu, Bharani; Naraharirao, Madhavan Hajib; Jambulingam, Malathi

    2016-03-01

    Emergence of extended-spectrum β-lactamase (ESBL) and fluoroquinolone resistance among ocular Enterobacteriaceae is increasing in higher frequency. Therefore, studies are being carried out to understand their multidrug resistance pattern. A total of 101 Enterobacteriaceae isolates recovered from various ocular diseases in a tertiary eye care center at Chennai, India during the period of January 2011 to June 2014 were studied. Forty one randomly chosen isolates were subjected to antibiotic susceptibility by minimum inhibitory concentration (MIC) and genotypic analysis. Of them, 16 were ESBL producers, one was carbapenemase producer and four were resistant to ertapenem which could be due to porin loss associated with AmpC production, and 17 were resistant to fluoroquinolones. Sixteen isolates harbored ESBL genes in which 14 had more than one gene and none of them were positive for blaNDM-1 gene. QNR genes were detected in 18 isolates. ESBL producers were predominantly isolated from conjunctiva. A high degree of ESBL production and fluoroquinolone resistance is seen among the genus Klebsiella sp. Hence, monitoring the rate of ESBL prevalence plays a vital role in the administration of appropriate intravitreal antibiotics to save the vision and also to reduce the development of drug resistance in ocular pathogens. PMID:27141313

  7. Characterization of Antibiotic Resistance Profiles of Ocular Enterobacteriaceae Isolates

    PubMed Central

    Paul-Satyaseela, Maneesh; Murali, Sowmiya; Thirunavukkarasu, Bharani; Naraharirao, Madhavan Hajib; Jambulingam, Malathi

    2016-01-01

    Emergence of extended-spectrum β-lactamase (ESBL) and fluoroquinolone resistance among ocular Enterobacteriaceae is increasing in higher frequency. Therefore, studies are being carried out to understand their multidrug resistance pattern. A total of 101 Enterobacteriaceae isolates recovered from various ocular diseases in a tertiary eye care center at Chennai, India during the period of January 2011 to June 2014 were studied. Forty one randomly chosen isolates were subjected to antibiotic susceptibility by minimum inhibitory concentration (MIC) and genotypic analysis. Of them, 16 were ESBL producers, one was carbapenemase producer and four were resistant to ertapenem which could be due to porin loss associated with AmpC production, and 17 were resistant to fluoroquinolones. Sixteen isolates harbored ESBL genes in which 14 had more than one gene and none of them were positive for blaNDM-1 gene. QNR genes were detected in 18 isolates. ESBL producers were predominantly isolated from conjunctiva. A high degree of ESBL production and fluoroquinolone resistance is seen among the genus Klebsiella sp. Hence, monitoring the rate of ESBL prevalence plays a vital role in the administration of appropriate intravitreal antibiotics to save the vision and also to reduce the development of drug resistance in ocular pathogens. PMID:27141313

  8. Molecular characterization and antibiotic susceptibility of Vibrio cholerae non-O1.

    PubMed Central

    Dalsgaard, A.; Serichantalergs, O.; Pitarangsi, C.; Echeverria, P.

    1995-01-01

    A collection of 64 clinical and environmental Vibrio cholerae non-O1 strains isolated in Asia and Peru were characterized by molecular methods and antibiotic susceptibility testing. All strains were resistant to at least 1 and 80% were resistant to two or more antibiotics. Several strains showed multiple antibiotic resistance (> or = three antibiotics). Plasmids most often of low molecular weight were found in 21/64 (33%) strains. The presence of plasmids did not correlate with antibiotic resistance or influence ribotype patterns. In colony hybridization studies 63/64 (98%) V. cholerae non-O1 strains were cholera toxin negative, whereas only strains recovered from patients were heat-stable enterotoxin positive. Forty-seven Bgl I ribotypes were observed. No correlation was shown between ribotype and toxin gene status. Ribotype similarity was compared by cluster analysis and two main groups of 13 and 34 ribotypes was found. Ribotyping is apparently a useful epidemiological tool in investigations of V. cholerae non-O1 infections. Images Fig. 1 PMID:7867743

  9. Analysis of antibiotic susceptibility and resistance of leg ulcer bacterial flora in patients hospitalized at Dermatology Department, Poznań University Hospital.

    PubMed

    Zmudzińska, Maria; Czarnecka-Operacz, Magdalena; Silny, Wojciech

    2005-01-01

    Effective treatment of frequently infected, poorly healing wounds such as leg ulcers due to chronic venous insufficiency poses a major clinical problem. Antibiotic resistance in dermatology patients, especially those with non-healing leg ulcers, is a widespread phenomenon. Various antibiotics, mainly broad-spectrum agents, are frequently and sometimes inappropriately prescribed, which often leads to the selection of antibiotic-resistant bacteria strains. The aim of this study was to analyze antibiotic susceptibility and resistance of bacterial isolates cultured from leg ulcers. Wound swabs were obtained from patients admitted to Dermatology Department, Poznań University of Medical Sciences, during the 1998-2002 period. Bacteriologic diagnosis of 175 wound swabs was performed in compliance with compulsory laboratory methods. The analysis yielded 173 positive results, predominated by Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecalis, Proteus mirabilis and Escherichia coli. Bacterial isolates were evaluated for resistance to commonly used antibiotics, taking into consideration the presence of methicillin resistant Staphylococcus aureus strains. Antibiotic resistance profiles were compared between the years 1998 and 2002, with detailed account of clinical characteristics and history of leg ulcers disease. The study pointed to an increasing tendency of antibiotic resistance in the study group of patients. PMID:16146620

  10. Antibiotic Susceptibility Patterns of Mycobacterium tuberculosis Isolates from Guizhou Province of China Against 13 Antituberculosis Drugs.

    PubMed

    Li, Nana; Liao, Xiaoqin; Chen, Ling; Wang, Jianhua; Liu, Mei; Zhang, Hong

    2015-06-01

    A total of 92 Mycobacterium tuberculosis isolates were collected from patients with pulmonary tuberculosis (TB) in the Zunyi region between 2011 and 2012. Collected isolates were used to determine antibiotic susceptibility patterns against 13 anti-TB drugs: 4 first-line and 9 second-line (ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin, para-aminosalicylic acid, amikacin, capreomycin, kanamycin, and prothionamide) drugs. Results showed that among 57 new cases of TB only 66.7% were susceptible to all four first-line anti-TB drugs and 64.9% were susceptible to fluoroquinolones and second-line injectables; 10.5% of new and 22.9% of previously treated cases were multidrug-resistant TB (MDR-TB); and 1.8% of new and 2.9% of previously treated cases were extensively drug-resistant TB (XDR-TB). In addition, 14.3% of MDR-TB cases (2 out of 14) were XDR-TB, which is higher than the average numbers in China (about 8%) and in the world (9.6%). This study confirms that primary transmission of drug-resistant TB, including MDR/XDR-TB, is a real threat to achieving effective control of drug-resistant TB in the Guizhou Province and indicates the necessity to determine antibiotic susceptibility patterns in patients with TB to improve treatment outcomes. PMID:25599413

  11. Antibiotic susceptibility of Acinetobacter species in intensive care unit in Montenegro.

    PubMed

    Mijovic, Gordana; Pejakov, Ljubica; Vujosevic, Danijela

    2016-08-01

    The global increase in multidrug resistance of Acinetobacter has created widespread problems in the treatment of patients in intensive care units (ICUs). The aim of this study was to assess the current level of antimicrobial susceptibility of Acinetobacter species in ICU of Clinical Centre of Montenegro and determine their epidemiology. Antibiotic susceptibility was tested in 70 isolates of Acinetobacter collected from non-repeating samples taken from 40 patients. The first nine isolates were genotyped by repetitive sequence-based PCR (rep-PCR). Tigecycline was found to be the most active antimicrobial agent with 80.6% of susceptibility. All the isolates were multidrug resistant with fully resistance to cefalosporinas, piperacillin and piperacillin/tazobactam. More than half of them (58.5%) were probably extensively resistant. Seven out of nine examined strains were clonally related by rep-PCR. Our results showed extremely high rate of multidrug resistance (MDR) of Acinetobacter isolates and high percentage of its clonally spreading. PMID:25979577

  12. A two-hour antibiotic susceptibility test by ATP-bioluminescence.

    PubMed

    March Rosselló, Gabriel Alberto; García-Loygorri Jordán de Urries, María Cristina; Gutiérrez Rodríguez, María Purificación; Simarro Grande, María; Orduña Domingo, Antonio; Bratos Pérez, Miguel Ángel

    2016-01-01

    The antibiotic susceptibility test (AST) in Clinical Microbiology laboratories is still time-consuming, and most procedures take 24h to yield results. In this study, a rapid antimicrobial susceptibility test using ATP-bioluminescence has been developed. The design of method was performed using five ATCC collection strains of known susceptibility. This procedure was then validated against standard commercial methods on 10 strains of enterococci, 10 staphylococci, 10 non-fermenting gram negative bacilli, and 13 Enterobacteriaceae from patients. The agreement obtained in the sensitivity between the ATP-bioluminescence method and commercial methods (E-test, MicroScan and VITEK2) was 100%. In summary, the preliminary results obtained in this work show that the ATP-bioluminescence method could provide a fast and reliable AST in two hours. PMID:25979598

  13. The erratic antibiotic susceptibility patterns of bacterial pathogens causing urinary tract infections.

    PubMed

    Ahmed, Iftkhar; Sajed, Muhammad; Sultan, Aneesa; Murtaza, Iram; Yousaf, Sohail; Maqsood, Bushra; Vanhara, Petr; Anees, Mariam

    2015-01-01

    Increasing trend of antibiotic resistance and expression of Extended Spectrum Beta Lactamases (ESBLs) are serious threats for public health as they render the treatment ineffective. Present study was designed to elucidate the antibiotic-susceptibility patterns of ESBL and non-ESBL producing E. coli and K. pneumoniae causing urinary tract infections so that the ineffective antibiotics could be removed from the line of treatment. The bacterial isolates obtained from the urine of patients visiting a tertiary health care facility were cultured for strain identification using API20E. Antimicrobial susceptibility and ESBL detection were done by Kirby-bauer diffusion technique. Almost 53.4 % isolates of E. coli and 24.5 % isolates of K. pneumoniae were found to be ESBL producers. The ESBL producing bacteria were found to be more resistant towards various antibiotics. The most effective drugs against E. coli ESBL isolates were imipenem (99.54 %), ampicillin-sulbactam (97.48 %), piperacillin-tazobactam (96.86 %), fosfomycin (94.51 %), amikacin (92.26 %) and nitrofurantoin (90.68 %). The most effective drugs against K. pneumoniae ESBL isolates were imipenem (97.62 %), piperacillin-tazobactam (95.35 %), ampicillin-sulbactam (90.48 %) and amikacin (88.37 %). The antibiotics having the highest resistance, particularly by the ESBL producers were amoxicillin clavulanic acid, sulphamethoxalzole/ trimethoprim, cefuroxime, cefpirome, ceftriaxone and ciprofloxacin. Most of the isolates showed multi drug resistance (MDR). High frequency of ESBL producing E. coli and K. pneumoniae were observed as compared to previous data. Penicillins, cephalosporins and some representatives of fluoroquinolones were least effective against the common UTIs and are recommended to be removed from the line of treatment. PMID:26648826

  14. The erratic antibiotic susceptibility patterns of bacterial pathogens causing urinary tract infections

    PubMed Central

    Ahmed, Iftkhar; Sajed, Muhammad; Sultan, Aneesa; Murtaza, Iram; Yousaf, Sohail; Maqsood, Bushra; Vanhara, Petr; Anees, Mariam

    2015-01-01

    Increasing trend of antibiotic resistance and expression of Extended Spectrum Beta Lactamases (ESBLs) are serious threats for public health as they render the treatment ineffective. Present study was designed to elucidate the antibiotic-susceptibility patterns of ESBL and non-ESBL producing E. coli and K. pneumoniae causing urinary tract infections so that the ineffective antibiotics could be removed from the line of treatment. The bacterial isolates obtained from the urine of patients visiting a tertiary health care facility were cultured for strain identification using API20E. Antimicrobial susceptibility and ESBL detection were done by Kirby-bauer diffusion technique. Almost 53.4 % isolates of E. coli and 24.5 % isolates of K. pneumoniae were found to be ESBL producers. The ESBL producing bacteria were found to be more resistant towards various antibiotics. The most effective drugs against E. coli ESBL isolates were imipenem (99.54 %), ampicillin-sulbactam (97.48 %), piperacillin-tazobactam (96.86 %), fosfomycin (94.51 %), amikacin (92.26 %) and nitrofurantoin (90.68 %). The most effective drugs against K. pneumoniae ESBL isolates were imipenem (97.62 %), piperacillin-tazobactam (95.35 %), ampicillin-sulbactam (90.48 %) and amikacin (88.37 %). The antibiotics having the highest resistance, particularly by the ESBL producers were amoxicillin clavulanic acid, sulphamethoxalzole/ trimethoprim, cefuroxime, cefpirome, ceftriaxone and ciprofloxacin. Most of the isolates showed multi drug resistance (MDR). High frequency of ESBL producing E. coli and K. pneumoniae were observed as compared to previous data. Penicillins, cephalosporins and some representatives of fluoroquinolones were least effective against the common UTIs and are recommended to be removed from the line of treatment. PMID:26648826

  15. Temporal Variabilities in Genetic Patterns and Antibiotic Resistance Profiles of Enterococci Isolated from Human Feces

    PubMed Central

    Nishiyama, Masateru; Shimauchi, Hidetaka; Suzuki, Yoshihiro

    2016-01-01

    Temporal variabilities in the genetic patterns and antibiotic resistance profiles of enterococci were monitored over a 7-month period. Enterococcus faecalis isolates (103 strains) collected from feces showed only one genetic pattern and antibiotic resistance profile within 0 d and 30 d. In contrast, after 60 d and 90 d, the genetic patterns and antibiotic resistance profiles of all E. faecalis isolates (8 strains) clearly differed within 30 d. These results indicate that the genetic patterns and antibiotic resistance profiles of E. faecalis in human feces changed to completely dissimilar patterns between 1 and 2 months. PMID:27265342

  16. Susceptibility to COPD: Differential Proteomic Profiling after Acute Smoking

    PubMed Central

    Franciosi, Lorenza; Postma, Dirkje S.; van den Berge, Maarten; Govorukhina, Natalia; Horvatovich, Peter L.; Fusetti, Fabrizia; Poolman, Bert; Lodewijk, Monique E.; Timens, Wim; Bischoff, Rainer; ten Hacken, Nick H. T.

    2014-01-01

    Cigarette smoking is the main risk factor for COPD (Chronic Obstructive Pulmonary Disease), yet only a subset of smokers develops COPD. Family members of patients with severe early-onset COPD have an increased risk to develop COPD and are therefore defined as “susceptible individuals”. Here we perform unbiased analyses of proteomic profiles to assess how “susceptible individuals” differ from age-matched “non-susceptible individuals” in response to cigarette smoking. Epithelial lining fluid (ELF) was collected at baseline and 24 hours after smoking 3 cigarettes in young individuals susceptible or non-susceptible to develop COPD and older subjects with established COPD. Controls at baseline were older healthy smoking and non-smoking individuals. Five samples per group were pooled and analysed by stable isotope labelling (iTRAQ) in duplicate. Six proteins were selected and validated by ELISA or immunohistochemistry. After smoking, 23 proteins increased or decreased in young susceptible individuals, 7 in young non-susceptible individuals, and 13 in COPD in the first experiment; 23 proteins increased or decreased in young susceptible individuals, 32 in young non-susceptible individuals, and 11 in COPD in the second experiment. SerpinB3 and Uteroglobin decreased after acute smoke exposure in young non-susceptible individuals exclusively, whereas Peroxiredoxin I, S100A9, S100A8, ALDH3A1 (Aldehyde dehydrogenase 3A1) decreased both in young susceptible and non-susceptible individuals, changes being significantly different between groups for Uteroglobin with iTRAQ and for Serpin B3 with iTRAQ and ELISA measures. Peroxiredoxin I, SerpinB3 and ALDH3A1 increased in COPD patients after smoking. We conclude that smoking induces a differential protein response in ELF of susceptible and non-susceptible young individuals, which differs from patients with established COPD. This is the first study applying unbiased proteomic profiling to unravel the underlying mechanisms

  17. Serotype/serogroup-specific antibiotic non-susceptibility of invasive and non-invasive Streptococcus pneumoniae, Switzerland, 2004 to 2014.

    PubMed

    Hauser, Christoph; Kronenberg, Andreas; Allemann, Aurélie; Mühlemann, Kathrin; Hilty, Markus

    2016-05-26

    Concurrent analysis of antibiotic resistance of colonising and invasive Streptococcus pneumoniae gives a more accurate picture than looking at either of them separately. Therefore, we analysed 2,129 non-invasive and 10,996 invasive pneumococcal isolates from Switzerland from 2004 to 2014, which spans the time before and after the introduction of the heptavalent (PCV7) and 13-valent (PCV13) conjugated pneumococcal polysaccharide vaccines. Serotype/serogroup information was linked with all antibiotic resistance profiles. During the study period, the proportion of non-susceptible non-invasive and invasive isolates significantly decreased for penicillin, ceftriaxone, erythromycin and trimethoprim/sulfamethoxazole (TMP-SMX). This was most apparent in non-invasive isolates from study subjects younger than five years (penicillin (p = 0.006), erythromycin (p = 0.01) and TMP-SMX (p = 0.002)). Resistant serotypes/serogroups included in PCV7 and/or PCV13 decreased and were replaced by non-PCV13 serotypes (6C and 15B/C). Serotype/serogroup-specific antibiotic resistance rates were comparable between invasive and non-invasive isolates. Adjusted odds ratios of serotype/serogroup-specific penicillin resistance were significantly higher in the west of Switzerland for serotype 6B (1.8; 95% confidence interval (CI): 1.4-4.8), 9V (3.4; 95% CI: 2.0-5.7), 14 (5.3; 95% CI: 3.8-7.5), 19A (2.2; 95% CI: 1.6-3.1) and 19F (3.1; 95% CI: 2.1-4.6), probably due to variations in the antibiotic consumption. PMID:27254535

  18. Clinical Presentation and Antibiotic Susceptibility of Contact Lens Associated Microbial Keratitis

    PubMed Central

    Hedayati, Hesam; Ghaderpanah, Mahboubeh; Rasoulinejad, Seyed Ahmad; Montazeri, Mohammad

    2015-01-01

    Introduction. In recent years, the number of contact lens wearers has dramatically increased in Iran, particularly in youngsters. The purpose of current study was to assess the clinical presentation and antibiotic susceptibility of contact lens related microbial keratitis in Ahvaz, southwest of Iran. Methodology. A cross-sectional investigation of 26 patients (33 eyes) with contact lens induced corneal ulcers who were admitted to Imam Khomeini Hospital, Ahwaz City, from June 2012 to June 2013 was done. In order to study microbial culture and susceptibility of corneal ulcers, all of them were scraped. Results. Eight samples were reported as sterile. Pseudomonas aeruginosa (80%) in positive cultures was the most widely recognized causative organism isolated. This is followed by Staphylococcus aureus 12% and Enterobacter 8%. The results showed that 84% of the microorganism cases were sensitive to ciprofloxacin, while imipenem, meropenem, and ceftazidime were the second most effective antibiotics (76%). Conclusion. Results of current study show the importance of referring all contact lens wearers with suspected corneal infection to ophthalmologists for more cure. The corneal scraping culture and contact lens solution should be performed to guide antibiotic therapy. PMID:26770828

  19. Helicobacter pylori uptake and efflux: basis for intrinsic susceptibility to antibiotics in vitro.

    PubMed

    Bina, J E; Alm, R A; Uria-Nickelsen, M; Thomas, S R; Trust, T J; Hancock, R E

    2000-02-01

    We previously demonstrated (M. M. Exner, P. Doig, T. J. Trust, and R. E. W. Hancock, Infect. Immun. 63:1567-1572, 1995) that Helicobacter pylori has at least one nonspecific porin, HopE, which has a low abundance in the outer membrane but forms large channels. H. pylori is relatively susceptible to most antimicrobial agents but less susceptible to the polycationic antibiotic polymyxin B. We demonstrate here that H. pylori is able to take up higher basal levels of the hydrophobic fluorescent probe 1-N-phenylnaphthylamine (NPN) than Pseudomonas aeruginosa or Escherichia coli, consistent with its enhanced susceptibility to hydrophobic agents. Addition of polymyxin B led to a further increase in NPN uptake, indicative of a self-promoted uptake pathway, but it required a much higher amount of polymyxin B to yield a 50% increase in NPN uptake in H. pylori (6 to 8 microg/ml) than in P. aeruginosa or E. coli (0.3 to 0.5 microg/ml), suggesting that H. pylori has a less efficient self-promoted uptake pathway. Since intrinsic resistance involves the collaboration of restricted outer membrane permeability and secondary defense mechanisms, such as periplasmic beta-lactamase (which H. pylori lacks) or efflux, we examined the possible role of efflux in antibiotic susceptibility. We had previously identified in H. pylori 11637 the presence of portions of three genes with homology to potential restriction-nodulation-division (RND) efflux systems. It was confirmed that H. pylori contained only these three putative RND efflux systems, named here hefABC, hefDEF, and hefGHI, and that the hefGHI system was expressed only in vivo while the two other RND systems were expressed both in vivo and in vitro. In uptake studies, there was no observable energy-dependent tetracycline, chloramphenicol, or NPN efflux activity in H. pylori. Independent mutagenesis of the three putative RND efflux operons in the chromosome of H. pylori had no effect on the in vitro susceptibility of H. pylori to 19

  20. Antibiotic susceptibility and heterogeneity in technological traits of lactobacilli isolated from Algerian goat's milk.

    PubMed

    Bousmaha-Marroki, Leila; Marroki, Ahmed

    2015-08-01

    The objective of this study was to identify and study the heterogeneity of technological traits of lactobacilli from goat's milk of Algeria and to evaluate in vitro their safety aspect. Using API50 CHL system and 16S rDNA sequencing, 51 % of strains were assigned as Lactobacillus plantarum, 34 % as L. pentosus, 7 % as L. rhamnosus and 8 % as L. fermentum. A large variability was noted for the acidifying capacity in skim milk after 6, 12 and 24 h of incubation. All strains expressed aminopeptidase activity against alanine-ρ-NA and leucine-ρ-NA at different levels. All strains were resistant to vancomycin and most of strains showed more susceptibility to β-lactam antibiotic. High susceptibility toward the inhibitors of protein synthesis was also observed. Minimum inhibitory concentrations data obtained revealed that isolates were susceptible to penicillin and chloramphenicol, and resistant to gentamicin and vancomycin. Minimum inhibitory concentrations distribution of other antibiotics showed variability. The analysis of graphical representation of principal component analysis of technological properties of L. plantarum and L. pentosus strains showed diversity among the isolates. Finally, eight L. plantarum (LAM1, LAM3, LAM21, LAM25, LAM35, LF15, LAM34, and LAM35), four L. pentosus (LAM38, LAM39, LF9 and LF16) and two L. rhamnosus (LF3 and LF10) strains, could be good candidates as adjunct culture in dairy product in Algeria. PMID:26243893

  1. Identification and antibiotic susceptibility pattern of coagulase-negative staphylococci in various clinical specimens

    PubMed Central

    2013-01-01

    Objective: Antibiotic resistance is a global problem and is more prevalent in developing countries. Coagulase-negative staphylococci (CoNS) are recognized as important pathogen for nosocomial infections. This study was carried out to identify CoNS in various clinical specimens and to determine its antimicrobial susceptibility pattern. Methods: A total of 2989 specimens of blood, pus and wound swab were collected from wards, casualty, ICU and OPD, out of these, staphylococci were isolated in 1000 specimens, of which 381 were identified as CoNS. Culture, gram stain, catalase, coagulase test and antimicrobial susceptibility pattern were done according to clinical manual of microbiology. A total of fourteen antibiotics were used in this study. Susceptibility testing was done by Kirby Bauer disc diffusion technique. Results: Antimicrobial resistance of CoNS were Oxacillin (70.3%), Amoxicillin (74.8%), Amoxicillin+clavulanate (32.8%), Ciprofloxacin (35.2%), Ofloxacin (33.6%), Ceftriaxone (30.4%), Erythromycin (58.3%), Clindamycin (16.3%), Daptomycin (42.5%), Kanamycin (52.2%), Fusidic acid (41.7%), Doxycycline (24.7%), Vancomycin (2.6%) and Linezolid (0.8%). Maximum Oxacillin resistance was between 80 to 90 percent in a group of patients having age of 45 to 65 years and those suffering from cancer or admitted in ICU. Conclusion: The study concluded that CoNS showed significant level of resistance against most of the widely used therapeutic agents. PMID:24550966

  2. Identification of clinical isolates of nondiphtherial Corynebacterium species and their antibiotic susceptibility patterns.

    PubMed

    Williams, D Y; Selepak, S T; Gill, V J

    1993-07-01

    Starting in 1982, our laboratory has performed species identification of coryneform bacteria isolated from blood cultures, intravenous (i.v.) catheter tips and sites, urines with high colony counts, and other potentially significant cultures, using predefined criteria. Of 283 isolates identified, Corynebacterium jeikeium was the most common (47%), followed by CDC group G2 (12%) and C. minutissimum (8%). Blood cultures and i.v. catheter-related sources were the most frequent sources (58% of total). Certain species or groups, like CDC group G2, were most frequently isolated from blood or i.v. catheter sites. CDC group G2 showed a progression to greater multiple antibiotic resistance during this 9-year period. Occasional multiresistant strains of other species were also encountered. By in vitro testing, we note vancomycin remains the most active agent against corynebacterialike organisms, and is the most reliable antibiotic to use while awaiting susceptibility testing results. PMID:8359002

  3. In vitro antibiotic susceptibility of field isolates of Mycoplasma synoviae in Argentina.

    PubMed

    Cerdá, R O; Giacoboni, G I; Xavier, J A; Sansalone, P L; Landoni, M F

    2002-01-01

    Minimum inhibitory concentrations (MICs) were determined in vitro for 7 antibiotics (aivlosin, enrofloxacine, tylosin, tiamulin, kitasamycin, chlortetracycline, and oxytetracycline) against eight recent local Argentinean isolates and two standard strains of Mycoplasma synoviae. Aivlosin (3-acetyl-4"-isovaleryl tylosin tartrate), tylosin, and tiamulin showed the lowest MICs with MIC90s of 0.006, 0.012, and 0.05 microg/ml, respectively. Except one strain that showed resistant values to chlortetracycline (> or = 12.5 microg/ml), all the analyzed strains were susceptible in different degrees to all the antibiotics tested. In this study, the improved activity of the tylosin-derived drug, aivlosin, was confirmed because it showed, in most strains, MIC values half those for tylosin. PMID:11922338

  4. Antibiotic Susceptibility Evaluation of Group A Streptococcus Isolated from Children with Pharyngitis: A Study from Iran

    PubMed Central

    2015-01-01

    Background The aim of this study was to evaluate the antibiotic susceptibility of Group A streptococcus (GAS) to antibiotics usually used in Iran for treatment of GAS pharyngitis in children. Materials and Methods From 2011 to 2013, children 3-15 years of age with acute tonsillopharyngitis who attended Mofid Children's Hospital clinics and emergency ward and did not meet the exclusion criteria were enrolled in a prospective study in a sequential manner. The isolates strains from throat culture were identified as GAS by colony morphology, gram staining, beta hemolysis on blood agar, sensitivity to bacitracin, a positive pyrrolidonyl aminopeptidase (PYR) test result, and the presence of Lancefield A antigen determined by agglutination test. Antimicrobial susceptibility was identified by both disk diffusion and broth dilution methods. Results From 200 children enrolled in this study, 59 (30%) cases were culture positive for GAS. All isolates were sensitive to penicillin G. The prevalence of erythromycin, azithromycin, and clarithromycin resistance by broth dilution method was 33.9%, 57.6%, and 33.9%, respectively. Surprisingly, 8.4% of GAS strains were resistant to rifampin. In this study, 13.5% and 32.2% of the strains were resistant to clindamycin and ofloxacin, respectively. Conclusion The high rate of resistance of GAS to some antibiotics in this study should warn physicians, especially in Iran, to use antibiotics restrictedly and logically to prevent the rising of resistance rates in future. It also seems that continuous local surveillance is necessary to achieve the best therapeutic option for GAS treatment. PMID:26788405

  5. Molecular Epidemiological and Antibiotic Susceptibility Characterization of Brucella Isolates from Humans in Sicily, Italy▿

    PubMed Central

    Marianelli, Cinzia; Graziani, Caterina; Santangelo, Carmela; Xibilia, Maria Teresa; Imbriani, Alida; Amato, Rosa; Neri, Domenico; Cuccia, Mario; Rinnone, Sebastiano; Di Marco, Vincenzo; Ciuchini, Franco

    2007-01-01

    Brucellosis is a serious problem in Sicily. Brucella melitensis was identified as the species most frequently isolated in humans in Italy. No data, however, are available about the molecular epidemiological characterization of Brucella isolates from humans. We have conducted this study to molecularly characterize clinical isolates of Brucella spp. and to evaluate their antimicrobial susceptibilities. Twenty Brucella isolates were studied. Differential growth characteristics and DNA polymorphisms such as the restriction patterns of the PCR-amplified omp2a and omp2b genes, rpoB nucleotide sequencing, and multiple-locus variable-number tandem repeat analysis of 16 loci (MLVA-16) were used to characterize the strains. In vitro antibiotic susceptibility was determined by the E-test method on two different agar media, and the results were compared. All isolates were identified as B. melitensis biovar 3. rpoB nucleotide sequence analysis allowed the identification of two different genotypes of B. melitensis biovar 3. On the other hand, the MLVA-16 typing assay recognized 17 distinct genotypes. All isolates were sensitive to all tested antibiotics (rifampin, doxycycline, ciprofloxacin, ceftriaxone, and trimethoprim-sulfamethoxazole), and the Mueller-Hinton agar plate is recommended for antibiotic susceptibility testing by the E-test method. Our findings identify B. melitensis biovar 3 as the etiological agent isolated in Sicily and encourage the use of both molecular methods, and in particular of the MLVA-16 assay, in epidemiological trace-back analysis. This study represents the first epidemiological data from molecular typing of Brucella strains circulating in Italy and, in particular, in eastern Sicily. PMID:17634297

  6. Virulence, Speciation and Antibiotic Susceptibility of Ocular Coagualase Negative Staphylococci (CoNS)

    PubMed Central

    Priya, Ravindran; Mythili, Arumugam; Singh, Yendremban Randhir Babu; Sreekumar, Haridas; Manikandan, Palanisamy; Panneerselvam, Kanesan

    2014-01-01

    Background: Coagulase negative Staphylococci (CoNS) are common inhabitants of human skin and mucous membranes. With the emergence of these organisms as prominent pathogens in patients with ocular infections, investigation has intensified in an effort to identify important virulence factors and to inform new approaches to treatment and prevention. Aim: To isolate CoNS from ocular specimens; to study the possible virulence factors; speciation of coagulase negative staphylococci (CoNS) which were isolated from ocular complications; antibiotic susceptibility testing of ocular CoNS. Materials and Methods: The specimens were collected from the target patients who attended the Microbiology Laboratory of a tertiary care eye hospital in Coimbatore, Tamilnadu state, India. The isolates were subjected to tube and slide coagulase tests for the identification of CoNS. All the isolates were subjected to screening for lipase and protease activities. Screening for other virulence factors viz., slime production on Congo red agar medium and haemagglutination assay with use of 96-well microtitre plates. These isolates were identified upto species level by performing biochemical tests such as phosphatase test, arginine test, maltose and trehalose fermentation tests and novobiocin sensitivity test. The isolates were subjected to antibiotic susceptibility studies, based on the revised standards of Clinical and Laboratory Standards Institutes (CLSI). Results: During the one year of study, among the total 260 individuals who were screened, 100 isolates of CoNS were obtained. Lipolytic activity was seen in all the isolates, whereas 38 isolates showed a positive result for protease. A total of 63 isolates showed slime production. Of 100 isolates, 30 isolates were analyzed for haemagglutination, where 4 isolates showed the capacity to agglutinate the erythrocytes. The results of the biochemical analysis revealed that of the 100 isolates of CoNS, 43% were Staphylococcus epidermidis. The other

  7. In Vitro Susceptibility of Pythium insidiosum Isolates to Aminoglycoside Antibiotics and Tigecycline

    PubMed Central

    Mahl, Deise Luiza; de Jesus, Francielli Pantella Kunz; Loreto, Érico Silva; Zanette, Régis Adriel; Ferreiro, Laerte; Pilotto, Maiara Ben; Alves, Sydney Hartz

    2012-01-01

    This study evaluated the in vitro activity of aminoglycoside antibiotics and tigecycline against Pythium insidiosum. The susceptibility tests were carried out using the broth microdilution method in accordance with the CLSI document M38-A2. MIC values for gentamicin, neomycin, paromomycin, and streptomycin ranged from 32 to 64 mg/liter, and the minimal fungicidal concentration (MFC) ranged from 32 to 128 mg/liter, which are incompatible with safe concentrations of these drugs in plasma in vivo. Tigecycline showed the lowest MIC (0.25 to 2 mg/liter) and MFC (1 to 8 mg/liter) range values. The in vitro susceptibility observed to tigecycline makes this drug a good option in future tests in vitro and in vivo for the management of pythiosis. PMID:22508303

  8. In vitro susceptibility of Pythium insidiosum isolates to aminoglycoside antibiotics and tigecycline.

    PubMed

    Mahl, Deise Luiza; de Jesus, Francielli Pantella Kunz; Loreto, Érico Silva; Zanette, Régis Adriel; Ferreiro, Laerte; Pilotto, Maiara Ben; Alves, Sydney Hartz; Santurio, Janio Morais

    2012-07-01

    This study evaluated the in vitro activity of aminoglycoside antibiotics and tigecycline against Pythium insidiosum. The susceptibility tests were carried out using the broth microdilution method in accordance with the CLSI document M38-A2. MIC values for gentamicin, neomycin, paromomycin, and streptomycin ranged from 32 to 64 mg/liter, and the minimal fungicidal concentration (MFC) ranged from 32 to 128 mg/liter, which are incompatible with safe concentrations of these drugs in plasma in vivo. Tigecycline showed the lowest MIC (0.25 to 2 mg/liter) and MFC (1 to 8 mg/liter) range values. The in vitro susceptibility observed to tigecycline makes this drug a good option in future tests in vitro and in vivo for the management of pythiosis. PMID:22508303

  9. Impact of Acinetobacter baumannii Superoxide Dismutase on Motility, Virulence, Oxidative Stress Resistance and Susceptibility to Antibiotics

    PubMed Central

    Heider, Christine; Skiebe, Evelyn; Wilharm, Gottfried

    2014-01-01

    Acinetobacter baumannii is a Gram-negative bacterium appearing as an opportunistic pathogen in hospital settings. Superoxide dismutase (SOD) contributes to virulence in several pathogenic bacteria by detoxifying reactive oxygen species released in the course of host defense reactions. However, the biological role of SODs in A. baumannii has not yet been elucidated. Here, we inactivated in A. baumannii ATCC 17978 gene A1S_2343, encoding a putative SOD of the Fe-Mn type by transposon insertion, resulting in mutant ATCC 17978 sod2343::Km. The mutation was also introduced in two naturally competent A. baumannii isolates by transformation with chromosomal DNA derived from mutant ATCC 17978 sod2343::Km. We demonstrate that inactivation of sod2343 leads to significant motility defects in all three A. baumannii strains. The mutant strains were more susceptible to oxidative stress compared to their parental strains. Susceptibility to colistin and tetracycline was increased in all mutant strains while susceptibility of the mutants to gentamicin, levofloxacin and imipenem was strain-dependent. In the Galleria mellonella infection model the mutant strains were significantly attenuated. In conclusion, sod2343 plays an important role in motility, resistance to oxidative stress, susceptibility to antibiotics and virulence in A. baumannii. PMID:25000585

  10. Development of an Antibiotic Spectrum Score Based on Veterans Affairs Culture and Susceptibility Data for the Purpose of Measuring Antibiotic De-Escalation: A Modified Delphi Approach

    PubMed Central

    Madaras-Kelly, Karl; Jones, Makoto; Remington, Richard; Hill, Nicole; Huttner, Benedikt; Samore, Matthew

    2016-01-01

    OBJECTIVE Development of a numerical score to measure the microbial spectrum of antibiotic regimens (spectrum score) and method to identify antibiotic de-escalation events based on application of the score. DESIGN Web-based modified Delphi method. PARTICIPANTS Physician and pharmacist antimicrobial stewards practicing in the United States recruited through infectious diseases–focused listservs. METHODS Three Delphi rounds investigated: organisms and antibiotics to include in the spectrum score, operationalization of rules for the score, and de-escalation measurement. A 4-point ordinal scale was used to score antibiotic susceptibility for organism-antibiotic domain pairs. Antibiotic regimen scores, which represented combined activity of antibiotics in a regimen across all organism domains, were used to compare antibiotic spectrum administered early (day 2) and later (day 4) in therapy. Changes in spectrum score were calculated and compared with Delphi participants’ judgments on de-escalation with 20 antibiotic regimen vignettes and with non-Delphi steward judgments on de-escalation of 300 pneumonia regimen vignettes. Method sensitivity and specificity to predict expert de-escalation status were calculated. RESULTS Twenty-four participants completed all Delphi rounds. Expert support for concepts utilized in metric development was identified. For vignettes presented in the Delphi, the sign of change in score correctly classified de-escalation in all vignettes except those involving substitution of oral antibiotics. The sensitivity and specificity of the method to identify de-escalation events as judged by non-Delphi stewards were 86.3% and 96.0%, respectively. CONCLUSIONS Identification of de-escalation events based on an algorithm that measures microbial spectrum of antibiotic regimens generally agreed with steward judgments of de-escalation status. PMID:25111918

  11. Diversity and antibiotic susceptibility of autochthonous dairy enterococci isolates: are they safe candidates for autochthonous starter cultures?

    PubMed Central

    Terzić-Vidojević, Amarela; Veljović, Katarina; Begović, Jelena; Filipić, Brankica; Popović, Dušanka; Tolinački, Maja; Miljković, Marija; Kojić, Milan; Golić, Nataša

    2015-01-01

    Enterococci represent the most controversial group of dairy bacteria. They are found to be the main constituent of many traditional Mediterranean dairy products and contribute to their characteristic taste and flavor. On the other hand, during the last 50 years antibiotic-resistant enterococci have emerged as leading causes of nosocomial infections worldwide. The aim of this study was to determine the diversity, technological properties, antibiotic susceptibility and virulence traits of 636 enterococci previously isolated from 55 artisan dairy products from 12 locations in the Western Balkan countries (WBC) of Serbia, Croatia and Bosnia and Herzegovina. All strains were identified both by microbiological and molecular methods. The predominant species was Enterococcus durans, followed by Enterococcus faecalis and Enterococcus faecium. Over 44% of the isolates were resistant to ciprofloxacin and erythromycin, while 26.2% of the isolates were multi-resistant to three or more antibiotics belonging to different families. 185 isolates (29.1%) were susceptible to all 13 of the antibiotics tested. The antibiotic-susceptible isolates were further tested for possible virulence genes and the production of biogenic amines. Finally, five enterococci isolates were found to be antibiotic susceptible with good technological characteristics and without virulence traits or the ability to produce biogenic amines, making them possible candidates for biotechnological application as starter cultures in the dairy industry. PMID:26441888

  12. Antimicrobial Susceptibility of Enterococcal Species Isolated from Antibiotic-Treated Dogs and Cats

    PubMed Central

    KATAOKA, Yasushi; UMINO, Yurie; OCHI, Hiroki; HARADA, Kazuki; SAWADA, Takuo

    2014-01-01

    ABSTRACT In this study, we examined the antimicrobial susceptibility of the enterococci isolated from dogs and cats in Japan during 2011–2012. Fecal samples were collected from 84 dogs and 16 cats that underwent antibiotic treatment. Enterococci were detected in 70 of 84 dogs (83.3%) and 7 of 16 cats (43.8%). The most prevalent Enterococcus species was Enterococcus faecalis (64.9%); Enterococccus faecium and Enterococcus durans were also isolated from 14 of 77 (18.2%) and 5 of 77 (6.5%) of these animals, respectively. The most active resistance was observed for erythromycin (44.2%) and oxytetracycline (44.2%), and there was considerable resistance to lincomycin (41.6%), gentamicin (31.2%) and kanamycin (31.2%). Compared with the results of a similar study conducted in 2006 and 2007, enterococci susceptibility to enrofloxacin and ampicillin had significantly increased. Enterococcus gallinarum harboring vanC1 and Enterococcus casseliflavus harboring vanC2/3 were isolated from 4 of 77 enterococcal isolates. However, no enterococcal isolates were resistant to vancomycin. Multidrug resistance was found for as few as two and as many as nine antimicrobials regardless of the class. These results demonstrate that dogs and cats treated with antibiotics are commonly colonized with antimicrobial-resistant enterococci. PMID:24976587

  13. Antibiotic susceptibility of sulfamethoxazole-trimethoprim resistant Stenotrophomonas maltophilia strains isolated at a tertiary care centre in Hungary.

    PubMed

    Juhász, Emese; Pongrácz, Júlia; Iván, Miklós; Kristóf, Katalin

    2015-09-01

    Sulfamethoxazole-trimethoprim (SXT) is the drug-of-choice in Stenotrophomonas maltophilia caused infections. There has been an increase in resistance to SXT of S. maltophilia over recent years. In this study 30 S. maltophilia clinical isolates resistant to SXT were investigated. Antibiotic susceptibilities for ciprofloxacin, moxifloxacin, levofloxacin, doxycycline, tigecycline, ceftazidime, colistin and chloramphenicol were determined by broth microdilution method. None of the strains were susceptible to ciprofloxacin, tigecycline, ceftazidime or colistin. Only 37% of the isolates were susceptible to levofloxacin or moxifloxacin. Two isolates resistant to all tested antibiotic agents and two others susceptible only to doxycycline were further investigated: susceptibility for combinations of antibiotics was analyzed by checkerboard technique. According to the fractional inhibitory concentration indices calculated, moxifloxacin plus ceftazidime combination was found to be synergistic in each case. Genetic testing revealed the predominance of sul1 gene. Our study concluded that the range of effective antibiotic agents is even more limited in infections caused by SXT-resistant S. maltophilia. In these cases, in vitro synergistic antibiotic combinations could be potential therapeutic options. PMID:26551572

  14. Population genetics and antibiotic susceptibility of invasive Haemophilus influenzae in Manitoba, Canada, from 2000 to 2006.

    PubMed

    Sill, Michelle L; Law, Dennis K S; Zhou, Jianwei; Skinner, Stuart; Wylie, John; Tsang, Raymond S W

    2007-11-01

    One hundred and twenty-two isolates of Haemophilus influenzae causing invasive disease were collected in Manitoba, Canada, from 2000 to 2006 and examined for serotype, biotype, sequence type (ST) by multilocus sequence typing and antibiotic susceptibility. Nonserotypeable (NST) isolates accounted for over half of the isolates collected (69 isolates, 56.6%). There were 36 serotype a, five serotype b, two serotype c, one serotype d, four serotype e and five serotype f isolates collected. The 69 NST isolates were found to be very diverse, with isolates representing six biotypes and 45 STs. The serotypeable isolates were more clonal, with each of the serotypes showing little diversity in their biotypes and STs. Of the 122 isolates, 17% were resistant to ampicillin due to beta-lactamase production, 10.7% were resistant to trimethoprim-sulfamethoxazole, 1.6% were resistant to clarithromycin, 2.5% were resistant to amoxicillin-clavulanic acid and none was resistant to ciprofloxacin or moxifloxacin. Antibiotic resistance was more common in the NST strains, with 37.7% showing resistance to at least one antibiotic compared to 15% in the serotypeable strains. The results of this study suggest a shift in the epidemiology of invasive H. influenzae infections in the post-Hib vaccine era, and surveillance should include all serotypeable and NST isolates. PMID:17922774

  15. Human Granulocyte Macrophage Colony-Stimulating Factor Enhances Antibiotic Susceptibility of Pseudomonas aeruginosa Persister Cells.

    PubMed

    Choudhary, Geetika S; Yao, Xiangyu; Wang, Jing; Peng, Bo; Bader, Rebecca A; Ren, Dacheng

    2015-01-01

    Bacterial persister cells are highly tolerant to antibiotics and cause chronic infections. However, little is known about the interaction between host immune systems with this subpopulation of metabolically inactive cells, and direct effects of host immune factors (in the absence of immune cells) on persister cells have not been studied. Here we report that human granulocyte macrophage-colony stimulating factor (GM-CSF) can sensitize the persister cells of Pseudomonas aeruginosa PAO1 and PDO300 to multiple antibiotics including ciprofloxacin, tobramycin, tetracycline, and gentamicin. GM-CSF also sensitized the biofilm cells of P. aeruginosa PAO1 and PDO300 to tobramycin in the presence of biofilm matrix degrading enzymes. The DNA microarray and qPCR results indicated that GM-CSF induced the genes for flagellar motility and pyocin production in the persister cells, but not the normal cells of P. aeruginosa PAO1. Consistently, the supernatants from GM-CSF treated P. aeruginosa PAO1 persister cell suspensions were found cidal to the pyocin sensitive strain P. aeruginosa PAK. Collectively, these findings suggest that host immune factors and bacterial persisters may directly interact, leading to enhanced susceptibility of persister cells to antibiotics. PMID:26616387

  16. Human Granulocyte Macrophage Colony-Stimulating Factor Enhances Antibiotic Susceptibility of Pseudomonas aeruginosa Persister Cells

    PubMed Central

    Choudhary, Geetika S.; Yao, Xiangyu; Wang, Jing; Peng, Bo; Bader, Rebecca A.; Ren, Dacheng

    2015-01-01

    Bacterial persister cells are highly tolerant to antibiotics and cause chronic infections. However, little is known about the interaction between host immune systems with this subpopulation of metabolically inactive cells, and direct effects of host immune factors (in the absence of immune cells) on persister cells have not been studied. Here we report that human granulocyte macrophage-colony stimulating factor (GM-CSF) can sensitize the persister cells of Pseudomonas aeruginosa PAO1 and PDO300 to multiple antibiotics including ciprofloxacin, tobramycin, tetracycline, and gentamicin. GM-CSF also sensitized the biofilm cells of P. aeruginosa PAO1 and PDO300 to tobramycin in the presence of biofilm matrix degrading enzymes. The DNA microarray and qPCR results indicated that GM-CSF induced the genes for flagellar motility and pyocin production in the persister cells, but not the normal cells of P. aeruginosa PAO1. Consistently, the supernatants from GM-CSF treated P. aeruginosa PAO1 persister cell suspensions were found cidal to the pyocin sensitive strain P. aeruginosa PAK. Collectively, these findings suggest that host immune factors and bacterial persisters may directly interact, leading to enhanced susceptibility of persister cells to antibiotics. PMID:26616387

  17. Effects of refrigerating preinoculated Vitek cards on microbial physiology and antibiotic susceptibility

    NASA Technical Reports Server (NTRS)

    Skweres, Joyce A.; Bassinger, Virginia J.; Mishra, S. K.; Pierson, Duane L.

    1992-01-01

    Reference cultures of 16 microorganisms obtained from the American Type Culture Collection and four clinical isolates were used in standardized solutions to inoculate 60 cards for each test strain. A set of three ID and three susceptibility cards was processed in the Vitek AutoMicrobic System (AMS) immediately after inoculation. The remaining cards were refrigerated at 4 C, and sets of six cards were removed and processed periodically for up to 17 days. The preinoculated AMS cards were evaluated for microorganism identification, percent probability of correct identification, length of time required for final result, individual substrate reactions, and antibiotic minimal inhibitory/concentration (MIC) values. Results indicate that 11 of the 20 microbes tested withstood refrigerated storage up to 17 days without detectable changes in delineating characteristics. MIC results appear variable, but certain antibiotics proved to be more stable than others. The results of these exploratory studies will be used to plan a microgravity experiment designed to study the effect of microgravity on microbial physiology and antibiotic sensitivity.

  18. Antepartum Antibiotic Treatment Increases Offspring Susceptibility to Experimental Colitis: A Role of the Gut Microbiota

    PubMed Central

    Munyaka, Peris Mumbi; Eissa, N.; Bernstein, Charles Noah; Khafipour, Ehsan; Ghia, Jean-Eric

    2015-01-01

    Background and aims Postnatal maturation of the immune system is largely driven by exposure to microbes, and thus the nature of intestinal colonization may be associated with development of childhood diseases that may persist into adulthood. We investigated whether antepartum antibiotic (ATB) therapy can increase offspring susceptibility to experimental colitis through alteration of the gut microbiota. Methods Pregnant C57Bl/6 mice were treated with cefazolin at 160 mg/kg body weight or with saline starting six days before due date. At 7 weeks, fecal samples were collected from male offspring after which they received 4% dextran sulfate sodium (DSS) in drinking water for 5 days. Disease activity index, histology, colonic IL-6, IL-1β and serum C-reactive protein (CRP) were determined. The V3-V4 region of colonic and fecal bacterial 16S rRNA was sequenced. Alpha-, beta-diversity and differences at the phylum and genus levels were determined, while functional pathways of classified bacteria were predicted. Results ATB influenced fecal bacterial composition and hence bacterial functional pathways before induction of colitis. After induction of colitis, ATB increased onset of clinical disease, histologic score, and colonic IL-6. In addition, ATB decreased fecal microbial richness, changed fecal and colon microbial composition, which was accompanied by a modification of microbial functional pathways. Also, several taxa were associated with ATB at lower taxonomical levels. Conclusions The results support the hypothesis that antepartum antibiotics modulate offspring intestinal bacterial colonization and increase susceptibility to develop colonic inflammation in a murine model of colitis, and may guide future interventions to restore physiologic intestinal colonization in offspring born by antibiotic-exposed mothers. PMID:26605545

  19. Relationship between antibiotic- and disinfectant-resistance profiles in bacteria harvested from tap water.

    PubMed

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

    2016-06-01

    Chlorination is commonly used to control levels of bacteria in drinking water; however, viable bacteria may remain due to chlorine resistance. What is concerning is that surviving bacteria, due to co-selection factors, may also have increased resistance to common antibiotics. This would pose a public health risk as it could link resistant bacteria in the natural environment to human population. Here, we investigated the relationship between chlorine- and antibiotic-resistances by harvesting 148 surviving bacteria from chlorinated drinking-water systems and compared their susceptibilities against chlorine disinfectants and antibiotics. Twenty-two genera were isolated, including members of Paenibacillus, Burkholderia, Escherichia, Sphingomonas and Dermacoccus species. Weak (but significant) correlations were found between chlorine-tolerance and minimum inhibitory concentrations against the antibiotics tetracycline, sulfamethoxazole and amoxicillin, but not against ciprofloxacin; this suggest that chlorine-tolerant bacteria are more likely to also be antibiotic resistant. Further, antibiotic-resistant bacteria survived longer than antibiotic-sensitive organisms when exposed to free chlorine in a contact-time assay; however, there were little differences in susceptibility when exposed to monochloramine. Irrespective of antibiotic-resistance, spore-forming bacteria had higher tolerance against disinfection compounds. The presence of chlorine-resistant bacteria surviving in drinking-water systems may carry additional risk of antibiotic resistance. PMID:26966812

  20. Antibiotic resistance profiles and virulence markers of Pseudomonas aeruginosa strains isolated from composts.

    PubMed

    Kaszab, Edit; Szoboszlay, Sándor; Dobolyi, Csaba; Háhn, Judit; Pék, Nikoletta; Kriszt, Balázs

    2011-01-01

    The aim of our work was to determine the presence of Pseudomonas aeruginosa in compost raw materials, immature and mature compost, and compost-treated soil. Twenty-five strains of P. aeruginosa were isolated from a raw material (plant straw), immature and mature compost and compost-treated soil samples. The strains were identified using the PCR method for the detection of species specific variable regions of 16S rDNA. Strains were examined for the presence of five different virulence-related gene sequences (exoA, exoU, exoT, exoS and exoY) and their antibiotic resistance profiles were determined. Based on our results, species P. aeruginosa can reach significant numbers (up to 10(6) MPN/g sample) during composting and 92.0% of the isolated strains carrying at least two gene sequences encoding toxic proteins. Various types of drug resistance were detected among compost originating strains, mainly against third generation Cephalosporins and Carbapenems. Six isolates were able to resist two different classes of antibiotics (third generation Cephalosporins and Carbapenems, wide spectrum Penicillins or Aminoglycosides, respectively). Based on our results, composts can be a source of P. aeruginosa and might be a concern to individuals susceptible to this opportunistic pathogen. PMID:20817443

  1. Antibiotic Susceptibility of Staphylococci Isolates from Patients with Chronic Conjunctivitis: Including Associated Factors and Clinical Evaluation

    PubMed Central

    Núñez, María Ximena

    2013-01-01

    Abstract Purpose To determine species of staphylococci in chronic conjunctivitis, their antibiotic susceptibility pattern, patient treatments, clinical course, and clinical conditions. Methods In this prospective study, 243 conjunctival cultures were taken from 191 patients with chronic conjunctivitis, we obtained staphylococci susceptibility patterns with E-test, and they were analyzed in coagulase-positive and negative. The minimum inhibitory concentration for 90% of isolates (MIC90) was determined for Staphylococcus aureus and Staphylococcus epidermidis. Additionally, clinical follow-up and associated factors of all patients were analyzed depending on methicillin resistance (MR) or susceptibility (MS) bacterial state. Results One hundred and eight (44%) cultures were positive; 81 positive cultures were Gram-positive of which, 77 were staphylococci, 29 coagulase-positive with S. aureus as the most prevalent, 89% MS, and 11% MR. And 48 were coagulase-negative with S. epidermidis as the most isolated with 36% of MS and 64% of MR. Poor susceptibility was found in the staphylococcus coagulase-negative/MR group. Moxifloxacin and vancomycin show the best in vitro activity for all isolates. The MIC90 of moxifloxacin and vancomycin were 0.064/1.5, 0.64/3.0, and 1/3.0 for S. aureus-MS, S. epidermidis-MS, and S. epidermidis-MR, respectively. The most frequently associated factors found in patients with positive culture for staphylococcus were exposure to the health care system 23 (29.87%) of 77 patients and dry eye 23 (29.87%) of 77 patients. Both with a proportion of 3 in 10. Conclusion Coagulase-negative staphylococci were the most frequently isolated from the conjunctiva with 58.33% of MR; even though multiresistance was detected, their susceptibility to a fourth-generation fluoroquinolone, commonly used, such as moxifloxacin, was preserved. PMID:23944906

  2. Phenotypic Profiling of Antibiotic Response Signatures in Escherichia coli Using Raman Spectroscopy

    PubMed Central

    Athamneh, A. I. M.; Alajlouni, R. A.; Wallace, R. S.; Seleem, M. N.

    2014-01-01

    Identifying the mechanism of action of new potential antibiotics is a necessary but time-consuming and costly process. Phenotypic profiling has been utilized effectively to facilitate the discovery of the mechanism of action and molecular targets of uncharacterized drugs. In this research, Raman spectroscopy was used to profile the phenotypic response of Escherichia coli to applied antibiotics. The use of Raman spectroscopy is advantageous because it is noninvasive, label free, and prone to automation, and its results can be obtained in real time. In this research, E. coli cultures were subjected to three times the MICs of 15 different antibiotics (representing five functional antibiotic classes) with known mechanisms of action for 30 min before being analyzed by Raman spectroscopy (using a 532-nm excitation wavelength). The resulting Raman spectra contained sufficient biochemical information to distinguish between profiles induced by individual antibiotics belonging to the same class. The collected spectral data were used to build a discriminant analysis model that identified the effects of unknown antibiotic compounds on the phenotype of E. coli cultures. Chemometric analysis showed the ability of Raman spectroscopy to predict the functional class of an unknown antibiotic and to identify individual antibiotics that elicit similar phenotypic responses. Results of this research demonstrate the power of Raman spectroscopy as a cellular phenotypic profiling methodology and its potential impact on antibiotic drug development research. PMID:24295982

  3. Prevalence and Antibiotic Susceptibility of Mycoplasma hominis and Ureaplasma urealyticum in Pregnant Women.

    PubMed

    Lee, Min Young; Kim, Myeong Hee; Lee, Woo In; Kang, So Young; Jeon, You La

    2016-09-01

    Mycoplasma hominis (M. hominis) and Ureaplasma urealyticum (U. urealyticum) are important opportunistic pathogens that cause urogenital infections and complicate pregnancy. The aim of this study was to investigate the prevalence, effects on pregnancy outcomes, and antimicrobial susceptibilities of M. hominis and U. urealyticum. We tested vaginal swabs obtained from 1035 pregnant women for the presence of genital mycoplasmas between June 2009 and May 2014. The laboratory and clinical aspects of genital mycoplasmas infection were reviewed retrospectively, and the identification and antimicrobial susceptibility of genital mycoplasmas were determined using the Mycoplasma IST-2 kit. A total of 571 instances of M. hominis and/or U. urealyticum were detected. Of them, M. hominis was detected in two specimens, whereas U. urealyticum was detected in 472 specimens. The remaining 97 specimens were positive for both M. hominis and U. urealyticum. Preterm deliveries were frequently observed in cases of mixed infection of M. hominis and U. urealyticum, and instances of preterm premature rupture of membrane were often found in cases of U. urealyticum. The rates of non-susceptible isolates to erythromycin, empirical agents for pregnant women, showed increasing trends. In conclusion, the prevalence of M. hominis and/or U. urealyticum infections in pregnant women is high, and the resistance rate of antimicrobial agents tends to increase. Therefore, to maintain a safe pregnancy, it is important to identify the isolates and use appropriate empirical antibiotics immediately. PMID:27401661

  4. Phenotype, genotype, and antibiotic susceptibility of Swedish and Thai oral isolates of Staphylococcus aureus

    PubMed Central

    Blomqvist, Susanne; Leonhardt, Åsa; Arirachakaran, Pratanporn; Carlen, Anette; Dahlén, Gunnar

    2015-01-01

    Objective The present study investigated phenotypes, virulence genotypes, and antibiotic susceptibility of oral Staphylococcus aureus strains in order to get more information on whether oral infections with this bacterium are associated with certain subtypes or related to an over-growth of the S. aureus variants normally found in the oral cavity of healthy carriers. Materials and methods A total number of 157 S. aureus strains were investigated. Sixty-two strains were isolated from Swedish adults with oral infections, 25 strains were from saliva of healthy Swedish dental students, and 45 strains were from tongue scrapings of HIV-positive subjects in Thailand, and 25 Thai strains from non-HIV controls. The isolates were tested for coagulase, nitrate, arginine, and hemolysin, and for the presence of the virulence genes: hlg, clfA, can, sdrC, sdrD, sdrE, map/eap (adhesins) and sea, seb, sec, tst, eta, etb, pvl (toxins). MIC90 and MIC50 were determined by E-test against penicillin V, oxacillin, amoxicillin, clindamycin, vancomycin, fusidic acid, and cefoxitin. Results While the hemolytic phenotype was significantly (p<0.001) more common among the Thai strains compared to Swedish strains, the virulence genes were found in a similar frequency in the S. aureus strains isolated from all four subject groups. The Panton-Valentine leukocidin (PVL) genotype was found in 73–100% of the strains. More than 10% of the strains from Swedish oral infections and from Thai HIV-positives showed low antibiotic susceptibility, most commonly for clindamycin. Only three methicillin-resistant S. aureus (MRSA) strains were identified, two from oral infections and one from a Thai HIV patient. Conclusions S. aureus is occasionally occurring in the oral cavity in both health and disease in Sweden and Thailand. It is therefore most likely that S. aureus in opportunistic oral infections originate from the oral microbiota. S. aureus should be considered in case of oral infections and complaints

  5. First national survey of antibiotic susceptibility of the Bacteroides fragilis group: emerging resistance to carbapenems in Argentina.

    PubMed

    Fernández-Canigia, Liliana; Litterio, Mirta; Legaria, María C; Castello, Liliana; Predari, Silvia C; Di Martino, Ana; Rossetti, Adelaida; Rollet, Raquel; Carloni, Graciela; Bianchini, Hebe; Cejas, Daniela; Radice, Marcela; Gutkind, Gabriel

    2012-03-01

    The antibiotic susceptibility rates of 363 clinical Bacteroides fragilis group isolates collected from 17 centers in Argentina during the period from 2006 to 2009 were as follows: piperacillin-tazobactam, 99%; ampicillin-sulbactam, 92%; cefoxitin, 72%; tigecycline, 100%; moxifloxacin, 91%; and clindamycin, 52%. No metronidazole resistance was detected in these isolates during this time period. Resistance to imipenem, doripenem, and ertapenem was observed in 1.1%, 1.6%, and 2.3% of B. fragilis group strains, respectively. B. fragilis species showed a resistance profile of 1.5% to imipenem, 1.9% to doripenem, and 2.4% to ertapenem. This is the first report of carbapenem resistance in Argentina. The cfiA gene was present in 8 out of 23 isolates, all of them belonging to the B. fragilis species and displaying reduced susceptibility or resistance to carbapenems (MICs ≥ 4 μg/ml). Three out of eight cfiA-positive isolates were fully resistant to carbapenems, while 5 out of 8 isolates showed low-level resistance (MICs, 4 to 8 μg/ml). The inhibition by EDTA was a good predictor of the presence of metallo-β-lactamases in the fully resistant B. fragilis strains, but discrepant results were observed for low-level resistant isolates. B. fragilis was more susceptible to antimicrobial agents than other Bacteroides species. Bacteroides vulgatus species was the most resistant to ampicillin-sulbactam and piperacillin-tazobactam, and B. thetaiotaomicron/ovatus strains showed the highest level of resistance to carbapenems, with an unknown resistance mechanism. B. vulgatus and the uncommon non-Bacteroides fragilis species were the most resistant to moxifloxacin, showing an overall resistance rate of 15.1%. PMID:22232282

  6. Antibiotic resistance profiles and quorum sensing-dependent virulence factors in clinical isolates of pseudomonas aeruginosa.

    PubMed

    Wang, Huafu; Tu, Faping; Gui, Zhihong; Lu, Xianghong; Chu, Weihua

    2013-06-01

    Pseudomonas aeruginosa produces multiple virulence factors that have been associated with quorum sensing. The aim of this study was to evaluate the prevalence of drug resistant profiles and quorum sensing related virulence factors. Pseudomonas aeruginosa were collected from different patients hospitalized in China, the isolates were tested for their susceptibility to different common antimicrobial drugs and detected QS-related virulence factors. We identified 170 isolates displaying impaired phenotypic activity, approximately 80 % of the isolates were found to exhibit the QS-dependent phenotypes, among them, 12 isolates were defective in AHLs production, and therefore considered QS-deficient strains. Resistance was most often observed to Cefazolin (81.2 %), followed by trimethoprim-sulfamethoxazole (73.5 %), ceftriaxone (62.4 %) and Cefotaxime, Levofloxacin, Ciprofloxacin (58.8 %), and to a lesser extent Meropenem (20.0 %), Cefepime (18.8 %), and Cefoperazone/sulbactam (2.4 %) The QS-deficient isolates that were negative for virulence factor production were generally less susceptible to the antimicrobials. The results showed a high incidences of antibiotic resistance and virulence properties in P. aeruginosa, and indicate that the clinical use of QS-inhibitory drugs that appear superior to conventional antimicrobials by not exerting any selective pressure on resistant strains. PMID:24426103

  7. Comparison of agar dilution and antibiotic gradient strip test with broth microdilution for susceptibility testing of swine Brachyspira species.

    PubMed

    Mirajkar, Nandita S; Gebhart, Connie J

    2016-03-01

    Production-limiting diseases in swine caused by Brachyspira are characterized by mucohemorrhagic diarrhea (B. hyodysenteriae and "B. hampsonii") or mild colitis (B. pilosicoli), while B. murdochii is often isolated from healthy pigs. Emergence of novel pathogenic Brachyspira species and strains with reduced susceptibility to commonly used antimicrobials has reinforced the need for standardized susceptibility testing. Two methods are currently used for Brachyspira susceptibility testing: agar dilution (AD) and broth microdilution (BMD). However, these tests have primarily been used for B. hyodysenteriae and rarely for B. pilosicoli. Information on the use of commercial susceptibility testing products such as antibiotic gradient strips is lacking. Our main objective was to validate and compare the susceptibility results, measured as the minimum inhibitory concentration (MIC), of 6 antimicrobials for 4 Brachyspira species (B. hyodysenteriae, "B. hampsonii", B. pilosicoli, and B. murdochii) by BMD and AD (tiamulin, valnemulin, lincomycin, tylosin, and carbadox) or antibiotic gradient strip (doxycycline) methods. In general, the results of a high percentage of all 4 Brachyspira species differed by ±1 log2 dilution or less by BMD and AD for tiamulin, valnemulin, lincomycin, and tylosin, and by BMD and antibiotic gradient strip for doxycycline. The carbadox MICs obtained by BMD were 1-5 doubling dilutions different than those obtained by AD. BMD for Brachyspira was quicker to perform with less ambiguous interpretation of results when compared with AD and antibiotic gradient strip methods, and the results confirm the utility of BMD in routine diagnostics. PMID:26965233

  8. [Susceptibility to antibiotics and biochemical activity of strains of Acinetobacter sp. isolated from various sources].

    PubMed

    Gospodarek, E

    1993-01-01

    The study was performed on 576 Acinetobacter strains isolated from clinical material, objects from hospital, environment, soil, water and from animals. Applying API 20NE system identification was following: A. baumanii (61.1%), A. junii (19.4%), A. haemolyticus (4.3%), A. lwoffii (3.3%), A. johnsonii (0.52%) and not belonging to above genus strains (11.3%). Over 47% strains of Acinetobacter were isolated from clinical material as the only bacteria (mainly from samples received from intensive care units and surgical and urological wards). Out of 23 antibiotics and antimicrobials used for investigation of 535 strains of Acinetobacter, most active were imipenem (99%) of susceptible strains, ofloxacin and ciprofloxacin (95%) and netilmicin (88%). Multiple resistant strains were isolated more frequently from hospital environment than from other sources--these were mostly A. baumanii and A. junii. PMID:8189806

  9. Virulence factors and antibiotic susceptibility in enterococci isolated from oral mucosal and deep infections

    PubMed Central

    Dahlén, Gunnar; Blomqvist, Susanne; Almståhl, Annica; Carlén, Anette

    2012-01-01

    Objective This study evaluates the presence of virulence factors and antibiotic susceptibility among enterococcal isolates from oral mucosal and deep infections. Methods Forty-three enterococcal strains from oral mucosal lesions and 18 from deep infections were isolated from 830 samples that were sent during 2 years to Oral Microbiology, University of Gothenburg, for analysis. The 61 strains were identified by 16S rDNA, and characterized by the presence of the virulence genes efa A (endocarditis gene), gel E (gelatinase gene), ace (collagen binding antigen gene), asa (aggregation substance gene), cyl A (cytolysin activator gene) and esp (surface adhesin gene), tested for the production of bacteriocins and presence of plasmids. MIC determination was performed using the E-test method against the most commonly used antibiotics in dentistry, for example, penicillin V, amoxicillin and clindamycin. Vancomycin was included in order to detect vancomycin-resistant enterococci (VRE) strains. Results Sixty strains were identified as Enterococcus faecalis and one as Enterococcus faecium. All the virulence genes were detected in more than 93.3% (efa A and esp) of the E. faecalis strains, while the presence of phenotypic characteristics was much lower (gelatinase 10% and hemolysin 16.7%). Forty-six strains produced bacteriocins and one to six plasmids were detected in half of the isolates. Conclusions Enterococcal strains from oral infections had a high virulence capacity, showed bacteriocin production and had numerous plasmids. They were generally susceptible to ampicillins but were resistant to clindamycin, commonly used in dentistry, and no VRE-strain was found. PMID:22368771

  10. Burn Wound Infections and Antibiotic Susceptibility Patterns at Pakistan Institute of Medical Sciences, Islamabad, Pakistan

    PubMed Central

    Saaiq, Muhammad; Ahmad, Shehzad; Zaib, Muhammad Salman

    2015-01-01

    BACKGROND Burn wound infections carry considerable mortality and morbidity amongst burn injury victims who have been successfully rescued through the initial resuscitation. This study assessed the prevalent microrganisms causing burn wound infections among hospitalized patients; their susceptibility pattern to commonly used antibiotics; and the frequency of infections with respect to the duration of the burn wounds. METHODS This study was carried out at Burn Care Centre, Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan over a period of two years (i.e. from June 2010 to May 2012). The study included all wound-culture-positive patients of either gender and all ages, who had sustained deep burns and underwent definitive management with wound excisions and skin auto-grafting. Patients with negative cultures of the wounds were excluded. Tissue specimens for culture and sensitivity were collected from burn wounds using standard collection techniques and analyzed at microbiological laboratory. RESULTS Out of a total of 95 positive microbial growths, 36 were Pseudomonas aeruginosa (35.29%) as the most frequent isolate found, followed by 21 Klebsiella pneumoniae (20.58%), 19 Staphylococcus aureaus (18.62%), 10 Proteus (9.80%), 7 E. coli (6.86%), 7 Acinetobacter (6.86%), and 4 Candida (3.92%). A variable antibiotic susceptibility pattern was observed among the grown microbes. Positive cultures were significantly more frequent among patients with over two weeks duration of burn wounds. CONCLUSION P. aeruginosa, K. pneumoniae and S. aureus constituted the most common bacterial microbes of burn wounds in our in-patients cases. Positive cultures were more frequent among patients with over two weeks duration of burn wounds. Early excision and skin grafting of deep burns and adherence to infection control measures can help to effectively reduce the burden of these infections. PMID:25606471

  11. Susceptibility of Clostridium perfringens strains from broiler chickens to antibiotics and anticoccidials.

    PubMed

    Martel, A; Devriese, L A; Cauwerts, K; De Gussem, K; Decostere, A; Haesebrouck, F

    2004-02-01

    Clostridium perfringens strains isolated in 2002 from the intestines of broiler chickens from 31 different farms located in Belgium were tested for susceptibility to 12 antibiotics used for therapy, growth promotion or prevention of coccidiosis. All strains were uniformly sensitive to the ionophore antibiotics monensin, lasalocid, salinomycin, maduramycin and narasin. All were sensitive to avilamycin, tylosin and amoxicillin, while flavomycin (bambermycin) showed low or no activity. Chlortetracycline and oxytetracycline were active at very low concentrations, but low-level acquired resistance was detected in 66% of the strains investigated. Fifty percent of these strains carried the tetP(B) resistance gene, while the tet(Q) gene was detected in only one strain. One strain with high-level resistance against tetracyclines carried the tet(M) gene. Sixty-three percent of the strains showed low-level resistance to lincomycin. The lnu(A) and lnu(B) genes were each only found in one strain. Compared with a similar investigation carried out in 1980, an increase was seen in resistance percentages with lincomycin (63% against 49%) and a slight decrease with tetracycline (66% against 74%). PMID:14681061

  12. Antibiotic Susceptibility of Biofilm Cells and Molecular Characterisation of Staphylococcus hominis Isolates from Blood

    PubMed Central

    Mendoza-Olazarán, Soraya; Morfín-Otero, Rayo; Villarreal-Treviño, Licet; Rodríguez-Noriega, Eduardo; Llaca-Díaz, Jorge; Camacho-Ortiz, Adrián; González, Gloria M.; Casillas-Vega, Néstor; Garza-González, Elvira

    2015-01-01

    Objectives We aimed to characterise the staphylococcal cassette chromosome mec (SCCmec) type, genetic relatedness, biofilm formation and composition, icaADBC genes detection, icaD expression, and antibiotic susceptibility of planktonic and biofilm cells of Staphylococcus hominis isolates from blood. Methods The study included 67 S. hominis blood isolates. Methicillin resistance was evaluated with the cefoxitin disk test. mecA gene and SCCmec were detected by multiplex PCR. Genetic relatedness was determined by pulsed-field gel electrophoresis. Biofilm formation and composition were evaluated by staining with crystal violet and by detachment assay, respectively; and the biofilm index (BI) was determined. Detection and expression of icaADBC genes were performed by multiplex PCR and real-time PCR, respectively. Antibiotic susceptibilities of planktonic cells (minimum inhibitory concentration, MIC) and biofilm cells (minimum biofilm eradication concentration, MBEC) were determined by the broth dilution method. Results Eighty-five percent (57/67) of isolates were methicillin resistant and mecA positive. Of the mecA-positive isolates, 66.7% (38/57) carried a new putative SCCmec type. Four clones were detected, with two to five isolates each. Among all isolates, 91% (61/67) were categorised as strong biofilm producers. Biofilm biomass composition was heterogeneous (polysaccharides, proteins and DNA). All isolates presented the icaD gene, and 6.66% (1/15) isolates expressed icaD. This isolate presented the five genes of ica operon. Higher BI and MBEC values than the MIC values were observed for amikacin, vancomycin, linezolid, oxacillin, ciprofloxacin, and chloramphenicol. Conclusions S. hominis isolates were highly resistant to methicillin and other antimicrobials. Most of the detected SCCmec types were different than those described for S. aureus. Isolates indicated low clonality. The results indicate that S. hominis is a strong biofilm producer with an extracellular

  13. Antibiotic resistance and plasmid profiling of Vibrio spp. in tropical waters of Peninsular Malaysia.

    PubMed

    You, K G; Bong, C W; Lee, C W

    2016-03-01

    Vibrio species isolated from four different sampling stations in the west coast of Peninsular Malaysia were screened for their antimicrobial resistance and plasmid profiles. A total of 138 isolates belonging to 15 different species were identified. Vibrio campbellii, V. parahaemolyticus, V. harveyi, and V. tubiashii were found to predominance species at all stations. High incidence of erythromycin, ampicillin, and mecillinam resistance was observed among the Vibrio isolates. In contrast, resistance against aztreonam, cefepime, streptomycin, sulfamethoxazole, and sulfonamides was low. All the Vibrio isolates in this study were found to be susceptible to imipenem, norfloxacin, ofloxacin, chloramphenicol, trimethoprim/sulfamethoxazole, and oxytetracycline. Ninety-five percent of the Vibrio isolates were resistant to one or more different classes of antibiotic, and 20 different resistance antibiograms were identified. Thirty-two distinct plasmid profiles with molecular weight ranging from 2.2 to 24.8 kb were detected among the resistance isolates. This study showed that multidrug-resistant Vibrio spp. were common in the aquatic environments of west coast of Peninsular Malaysia. PMID:26884358

  14. Antibiotic susceptibility patterns of Crossiella equi and Amycolatopsis species causing nocardioform placentitis in horses.

    PubMed

    Erol, Erdal; Williams, Neil M; Sells, Stephen F; Kennedy, Laura; Locke, Stephen J; Donahue, James M; Carter, Craig N

    2012-11-01

    Nocardioform actinomycetes are significant causes of placentitis and abortions in horses. In the current study, antimicrobial susceptibility patterns of 38 Amycolatopsis spp. and 22 Crossiella equi isolates, the most common nocardioform actinomycetes causing placentitis in horses, were evaluated. Antimicrobial susceptibilities of these isolates were tested by broth microdilution method in a commercial system, which was designed for Nocardia spp., fast-growing Mycobacterium spp., and other aerobic actinomycetes. The minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC(90)) of the following antibiotics tested for Amycolatopsis spp. were: 4 µg/ml for linezolid, trimethophrim-sulfametaxazole (TMP-SMX), and ciprofloxacin; 8 µg/ml for ceftriaxone, doxycycline, and minocycline; 16 µg/ml for amoxicillin-clavulanic acid, clarithromycin, and imipenem; >16 µg/ml for tobramycin; 32 µg/ml for amikacin and cefepime; and 128 µg/ml for cefoxitin. The MIC(90) levels for C. equi were 0.25 µg/ml for doxycycline; ≤1 µg/ml for minocycline; 2 µg/ml for linezolid and TMP-SMX; 4 µg/ml for ciprofloxacin; 8 µg/ml for amoxicillin-clavulanic acid, ceftriaxone, and imipenem; 16 µg/ml for clarithromycin; >16 µg/ml for tobramycin; 32 µg/ml for cefepime; >64 µg/ml for amikacin; and 128 µg/ml for cefoxitin. PMID:23051830

  15. Effect of various antibiotics on modulation of intestinal microbiota and bile acid profile in mice

    SciTech Connect

    Zhang, Youcai; Limaye, Pallavi B.; Renaud, Helen J.; Klaassen, Curtis D.

    2014-06-01

    Antibiotic treatments have been used to modulate intestinal bacteria and investigate the role of intestinal bacteria on bile acid (BA) homeostasis. However, knowledge on which intestinal bacteria and bile acids are modified by antibiotics is limited. In the present study, mice were administered various antibiotics, 47 of the most abundant bacterial species in intestine, as well as individual BAs in plasma, liver, and intestine were quantified. Compared to the two antibiotic combinations (vancomycin + imipenem and cephalothin + neomycin), the three single antibiotics (metronidazole, ciprofloxacin and aztreonam) have less effect on intestinal bacterial profiles, and thus on host BA profiles and mRNA expression of genes that are important for BA homeostasis. The two antibiotic combinations decreased the ratio of Firmicutes to Bacteroidetes in intestine, as well as most secondary BAs in serum, liver and intestine. Additionally, the two antibiotic combinations significantly increased mRNA of the hepatic BA uptake transporters (Ntcp and Oatp1b2) and canalicular BA efflux transporters (Bsep and Mrp2), but decreased mRNA of the hepatic BA synthetic enzyme Cyp8b1, suggesting an elevated enterohepatic circulation of BAs. Interestingly, the two antibiotic combinations tended to have opposite effect on the mRNAs of most intestinal genes, which tended to be inhibited by vancomycin + imipenem but stimulated by cephalothin + neomycin. To conclude, the present study clearly shows that various antibiotics have distinct effects on modulating intestinal bacteria and host BA metabolism. - Highlights: • Various antibiotics have different effects on intestinal bacteria. • Antibiotics alter bile acid composition in mouse liver and intestine. • Antibiotics influence genes involved in bile acid homeostasis. • Clostridia appear to be important for secondary bile acid formation.

  16. Vancomycin resistant enterococci in urine cultures: Antibiotic susceptibility trends over a decade at a tertiary hospital in the United Kingdom

    PubMed Central

    Toner, Liam; Papa, Nathan; Aliyu, Sani H.; Dev, Harveer; Al-Hayek, Samih

    2016-01-01

    Purpose Enterococci are a common cause of urinary tract infection and vancomycin-resistant strains are more difficult to treat. The purpose of this surveillance program was to assess the prevalence of and determine the risk factors for vancomycin resistance in adults among urinary isolates of Enterococcus sp. and to detail the antibiotic susceptibility profile, which can be used to guide empirical treatment. Materials and Methods From 2005 to 2014 we retrospectively reviewed 5,528 positive Enterococcus sp. urine cultures recorded in a computerized laboratory results database at a tertiary teaching hospital in Cambridge, United Kingdom. Results Of these cultures, 542 (9.8%) were vancomycin resistant. No longitudinal trend was observed in the proportion of vancomycin-resistant strains over the course of the study. We observed emerging resistance to nitrofurantoin with rates climbing from near zero to 40%. Ampicillin resistance fluctuated between 50% and 90%. Low resistance was observed for linezolid and quinupristin/dalfopristin. Female sex and inpatient status were identified as risk factors for vancomycin resistance. Conclusions The incidence of vancomycin resistance among urinary isolates was stable over the last decade. Although resistance to nitrofurantoin has increased, it still serves as an appropriate first choice in uncomplicated urinary tract infection caused by vancomycin-resistant Enterococcus sp. PMID:26981595

  17. Antibiotics

    MedlinePlus

    ... or not using them properly, can add to antibiotic resistance. This happens when bacteria change and become able ... survive and re-infect you. Do not save antibiotics for later or use someone else's prescription. Centers for Disease Control and Prevention

  18. Isolation and antibiotic susceptibility of Shigella species from stool samples among hospitalized children in Abadan, Iran

    PubMed Central

    Jomezadeh, Nabi; Babamoradi, Shahram; Kalantar, Enayatollah; Javaherizadeh, Hazhir

    2014-01-01

    Aim: The aim of this study was to determine the incidence of Shigella species and their antimicrobial susceptibility patterns in hospitalized children with Shigellosis in Abadan, Iran. Background: Shigellosis is caused by different species of Shigella and one of the most common causes of diarrhea in children. This disease is endemic in many developing countries including Iran. Patients and methods: This prospective cross sectional study was conducted in a teaching hospital in Abadan, Iran during June 2011 to May 2013. Stool specimens were collected from pediatric age group. All isolates were confirmed as Shigella species by biochemical and serologic tests. Antibiotic sensitivity pattern of these isolates was studied by disk diffusion Method. Results: Among all 705 stool samples, 36 (5.1%) yielded Shigella. Of cases, 392 (55.6%) were girl and 313 (44.4%) were boy. The most common Shigella isolates were S. flexneri (n=19, 52.7%) followed by S. sonnei (n=11, 30.5%), S. boydii (n=4, 11.1%) and S. dysenteriae 2(5.5%). Of the Shigella isolates, 47.2% showed resistance to two or more antimicrobial agents. Resistance pattern against various antimicrobials were as follows: trimethoprim-sulphamethoxazole (80.5%), ampicillin (63.8%), tetracycline (58.3%), chloramphenicol (33.3%), nalidixic acid (27.7%), and cefixime (16.6%). There was no resistance against ciprofloxacin and ceftriaxone. Conclusion: The most common isolates were S. flexneri followed by S. Sonnei. There was no antibiotic resistance against ciprofloxacin and ceftriaxone. TMP-SMZ showed highest resistance pattern. PMID:25289136

  19. Evaluation of Antibiotic Susceptibilities of Three Rickettsial Species Including Rickettsia felis by a Quantitative PCR DNA Assay

    PubMed Central

    Rolain, Jean-Marc; Stuhl, Laetitia; Maurin, Max; Raoult, Didier

    2002-01-01

    Rickettsiae grow only intracellularly, and the antibiotic susceptibilities of these bacteria have been assessed by either plaque, dye uptake, or immunofluorescence assays, which are time-consuming. We used a quantitative PCR (with the LightCycler instrument) to assess the levels of inhibition of Rickettisa felis, R. conorii, and R. typhi DNA synthesis in the presence of various antibiotics. We established the kinetics of rickettsial DNA during growth and showed that R. conorii grows more quickly than R. typhi in cell culture, with maximum replication occurring after 5 and 7 days, respectively. The MICs of the antibiotics tested for R. conorii and R. typhi by the quantitative PCR assay were similar to those previously obtained by plaque and dye uptake assays. We found that R. felis is susceptible to doxycycline, rifampin, thiamphenicol, and fluoroquinolones but not to gentamicin, erythromycin, amoxicillin, or trimethoprim-sulfamethoxazole. The resistance of this new species to erythromycin is consistent with its current taxonomic position within the spotted fever group. We believe that quantitative PCR could be used in the future to simplify and shorten antibiotic susceptibility assays of other rickettsiae and other strict intracellular pathogens. PMID:12183224

  20. Effect of NaCl on heat resistance, antibiotic susceptibility, and Caco-2 cell invasion of Salmonella.

    PubMed

    Yoon, Hyunjoo; Park, Beom-Young; Oh, Mi-Hwa; Choi, Kyoung-Hee; Yoon, Yohan

    2013-01-01

    This study evaluated the effects of NaCl on heat resistance, antibiotic susceptibility, and Caco-2 cell invasion of Salmonella. Salmonella typhimurium NCCP10812 and Salmonella enteritidis NCCP12243 were exposed to 0, 2, and 4% NaCl and to sequential increase of NaCl concentrations from 0 to 4% NaCl for 24 h at 35°C. The strains were then investigated for heat resistance (60°C), antibiotic susceptibility to eight antibiotics, and Caco-2 cell invasion efficiency. S. typhimurium NCCP10812 showed increased thermal resistance (P < 0.05) after exposure to single NaCl concentrations. A sequential increase of NaCl concentration decreased (P < 0.05) the antibiotic sensitivities of S. typhimurium NCCP10812 to chloramphenicol, gentamicin, and oxytetracycline. NaCl exposure also increased (P < 0.05) Caco-2 cell invasion efficiency of S. enteritidis NCCP12243. These results indicate that NaCl in food may cause increased thermal resistance, cell invasion efficiency, and antibiotic resistance of Salmonella. PMID:23936782

  1. Antibiotic resistant bacterial profiles of anaerobic swine lagoon effluent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although land application of swine manure lagoon effluent is a common and effective method of disposal, the presence of antibiotic-resistant bacteria, both pathogenic and commensal can complicate already understood issues associated with its safe disposal. To better understand this, more data is ne...

  2. Antibiotic Resistant Bacterial Profiles of Anaerobic Swine Lagoon Effluent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although land application of swine manure lagoon effluent is a common and effective method of disposal, the presence of antibiotic-resistant bacteria, both pathogenic and commensal can complicate already understood issues associated with its safe disposal. The aim of this study was to assess antibi...

  3. Multicentric study in five African countries of antibiotic susceptibility for three main pathogens: Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa.

    PubMed

    Zerouali, Khalid; Ramdani-Bouguessa, Nadjia; Boye, Cheikh; Hammami, Adnane

    2016-08-01

    Antibiotic resistance is a growing clinical and epidemiological problem. We report on the antibiotic susceptibility of three pathogens isolated from patients in Algeria, Egypt, Morocco, Senegal, and Tunisia during 2010-2011. In total, 218 Streptococcus pneumoniae, 428 Staphylococcus aureus, and 414 Pseudomonas aeruginosa strains were collected. S. pneumoniae resistance was noted against penicillin (30.2%), erythromycin (27.4%), cefpodoxime (19.1%), amoxicillin (12.0%), cefotaxime (7.4%), and levofloxacin (3.2%). All the strains were teicoplanin susceptible. Staphylococcus aureus methicillin resistance differed between countries, from 5.0% in Senegal to 62.7% in Egypt. Levofloxacin resistance was low in all countries, and the highest rate (in Egypt) was still only 13.6% for intermediate and resistant strains combined. Most strains were susceptible to fosfomycin (99.3%) and pristinamycin (94.2%). P. aeruginosa resistance was found against levofloxacin (30.4%), ciprofloxacin (29.9%), tobramycin (19.7%), ceftazidime (19.2%), and imipenem (17.9%), but not colistin. Antibiotic susceptibility varied widely between countries, with resistance typically most prevalent in Egypt. PMID:25363146

  4. Rapid evaluation of the antibiotic susceptibility of fuel ethanol contaminant biofilms.

    PubMed

    Rich, Joseph O; Leathers, Timothy D; Nunnally, Melinda S; Bischoff, Kenneth M

    2011-01-01

    Bacterial contaminants from commercial fuel ethanol production facilities were previously shown to form biofilms as mixed cultures under laboratory conditions. In this study, a rapid assay was developed to simultaneously compare isolates for their ability to form biofilms as pure cultures. A total of 10 strains were isolated from a dry-grind fuel ethanol plant that routinely doses with virginiamycin. These were identified by sequence analysis as six strains of Lactobacillus fermentum, two strains of L. johnsonii, and one strain each of L. mucosae and L. amylovorus. Isolates exhibited a range of susceptibility to virginiamycin in a planktonic assay, with MIC's (minimum inhibitory concentration) of ≤0.5-16 μg/ml. Even though all strains were isolated from a mixed culture biofilm, they varied greatly in their ability to form biofilms as pure cultures. Surprisingly, growth as biofilms did not appear to provide resistance to virginiamycin, even if biofilms were grown for 144 h prior to antibiotic challenge. PMID:20855199

  5. Antibiotic susceptibility, antibacterial activity and characterisation of Enterococcus faecium strains isolated from breast milk

    PubMed Central

    Kıvanç, Sertaç Argun; Kıvanç, Merih; Yiğit, Tülay

    2016-01-01

    Enterococci, which have useful biotechnological applications, produce bacteriocins, including those that exert anti-Listerial activity. The present study aimed to determine the antibiotic susceptibility patterns and antimicrobial activity of Enterococcus faecium strains isolated from human breast milk. The strains were identified using carbohydrate fermentation tests and ribotyping. Subsequently, the antibacterial activity of the isolates was investigated, and the quantities of lactic acid and hydrogen peroxide produced, and the proteolytic activity of E. faecium, were determined. In addition, biofilm formation by E. faecium strains was assessed. E. faecium strains exhibited antimicrobial activity against food-borne and clinical bacterial isolates. Furthermore, following 24 h incubation, the tested strains exhibited resistance to a pH range of 2.0–9.5 and tolerance of bile acid, lysozyme activity and phenol. Supernatants of the E. faecium TM13, TM15, TM17 and TM18 strains were shown to be effective against Listeria monocytogenes, and were also resistant to heat. Further studies are required in order to determine whether certain strains of E. faecium may be used for the development of novel antibacterial agents. PMID:27602088

  6. Antibiotic Susceptibility and Sequence Type Distribution of Ureaplasma Species Isolated from Genital Samples in Switzerland

    PubMed Central

    Schneider, Sarah C.; Tinguely, Regula; Droz, Sara; Hilty, Markus; Donà, Valentina; Bodmer, Thomas

    2015-01-01

    Antibiotic resistance in Ureaplasma urealyticum/Ureaplasma parvum and Mycoplasma hominis is an issue of increasing importance. However, data regarding the susceptibility and, more importantly, the clonality of these organisms are limited. We analyzed 140 genital samples obtained in Bern, Switzerland, in 2014. Identification and antimicrobial susceptibility tests were performed by using the Mycoplasma IST 2 kit and sequencing of 16S rRNA genes. MICs for ciprofloxacin and azithromycin were obtained in broth microdilution assays. Clonality was analyzed with PCR-based subtyping and multilocus sequence typing (MLST), whereas quinolone resistance and macrolide resistance were studied by sequencing gyrA, gyrB, parC, and parE genes, as well as 23S rRNA genes and genes encoding L4/L22 ribosomal proteins. A total of 103 samples were confirmed as positive for U. urealyticum/U. parvum, whereas 21 were positive for both U. urealyticum/U. parvum and M. hominis. According to the IST 2 kit, the rates of nonsusceptibility were highest for ciprofloxacin (19.4%) and ofloxacin (9.7%), whereas low rates were observed for clarithromycin (4.9%), erythromycin (1.9%), and azithromycin (1%). However, inconsistent results between microdilution and IST 2 kit assays were recorded. Various sequence types (STs) observed previously in China (ST1, ST2, ST4, ST9, ST22, and ST47), as well as eight novel lineages, were detected. Only some quinolone-resistant isolates had amino acid substitutions in ParC (Ser83Leu in U. parvum of serovar 6) and ParE (Val417Thr in U. parvum of serovar 1 and the novel Thr417Val substitution in U. urealyticum). Isolates with mutations in 23S rRNA or substitutions in L4/L22 were not detected. This is the first study analyzing the susceptibility of U. urealyticum/U. parvum isolates in Switzerland and the clonality outside China. Resistance rates were low compared to those in other countries. We hypothesize that some hyperepidemic STs spread worldwide via sexual intercourse

  7. Prediction of antibiotic resistance by gene expression profiles

    PubMed Central

    Suzuki, Shingo; Horinouchi, Takaaki; Furusawa, Chikara

    2014-01-01

    Although many mutations contributing to antibiotic resistance have been identified, the relationship between the mutations and the related phenotypic changes responsible for the resistance has yet to be fully elucidated. To better characterize phenotype–genotype mapping for drug resistance, here we analyse phenotypic and genotypic changes of antibiotic-resistant Escherichia coli strains obtained by laboratory evolution. We demonstrate that the resistances can be quantitatively predicted by the expression changes of a small number of genes. Several candidate mutations contributing to the resistances are identified, while phenotype–genotype mapping is suggested to be complex and includes various mutations that cause similar phenotypic changes. The integration of transcriptome and genome data enables us to extract essential phenotypic changes for drug resistances. PMID:25517437

  8. Comparative Genomics of Environmental and Clinical Stenotrophomonas maltophilia Strains with Different Antibiotic Resistance Profiles.

    PubMed

    Youenou, Benjamin; Favre-Bonté, Sabine; Bodilis, Josselin; Brothier, Elisabeth; Dubost, Audrey; Muller, Daniel; Nazaret, Sylvie

    2015-09-01

    Stenotrophomonas maltophilia, a ubiquitous Gram-negative γ-proteobacterium, has emerged as an important opportunistic pathogen responsible for nosocomial infections. A major characteristic of clinical isolates is their high intrinsic or acquired antibiotic resistance level. The aim of this study was to decipher the genetic determinism of antibiotic resistance among strains from different origins (i.e., natural environment and clinical origin) showing various antibiotic resistance profiles. To this purpose, we selected three strains isolated from soil collected in France or Burkina Faso that showed contrasting antibiotic resistance profiles. After whole-genome sequencing, the phylogenetic relationships of these 3 strains and 11 strains with available genome sequences were determined. Results showed that a strain's phylogeny did not match their origin or antibiotic resistance profiles. Numerous antibiotic resistance coding genes and efflux pump operons were revealed by the genome analysis, with 57% of the identified genes not previously described. No major variation in the antibiotic resistance gene content was observed between strains irrespective of their origin and antibiotic resistance profiles. Although environmental strains generally carry as many multidrug resistant (MDR) efflux pumps as clinical strains, the absence of resistance-nodulation-division (RND) pumps (i.e., SmeABC) previously described to be specific to S. maltophilia was revealed in two environmental strains (BurA1 and PierC1). Furthermore the genome analysis of the environmental MDR strain BurA1 showed the absence of SmeABC but the presence of another putative MDR RND efflux pump, named EbyCAB on a genomic island probably acquired through horizontal gene transfer. PMID:26276674

  9. Comparative Genomics of Environmental and Clinical Stenotrophomonas maltophilia Strains with Different Antibiotic Resistance Profiles

    PubMed Central

    Youenou, Benjamin; Favre-Bonté, Sabine; Bodilis, Josselin; Brothier, Elisabeth; Dubost, Audrey; Muller, Daniel; Nazaret, Sylvie

    2015-01-01

    Stenotrophomonas maltophilia, a ubiquitous Gram-negative γ-proteobacterium, has emerged as an important opportunistic pathogen responsible for nosocomial infections. A major characteristic of clinical isolates is their high intrinsic or acquired antibiotic resistance level. The aim of this study was to decipher the genetic determinism of antibiotic resistance among strains from different origins (i.e., natural environment and clinical origin) showing various antibiotic resistance profiles. To this purpose, we selected three strains isolated from soil collected in France or Burkina Faso that showed contrasting antibiotic resistance profiles. After whole-genome sequencing, the phylogenetic relationships of these 3 strains and 11 strains with available genome sequences were determined. Results showed that a strain’s phylogeny did not match their origin or antibiotic resistance profiles. Numerous antibiotic resistance coding genes and efflux pump operons were revealed by the genome analysis, with 57% of the identified genes not previously described. No major variation in the antibiotic resistance gene content was observed between strains irrespective of their origin and antibiotic resistance profiles. Although environmental strains generally carry as many multidrug resistant (MDR) efflux pumps as clinical strains, the absence of resistance–nodulation–division (RND) pumps (i.e., SmeABC) previously described to be specific to S. maltophilia was revealed in two environmental strains (BurA1 and PierC1). Furthermore the genome analysis of the environmental MDR strain BurA1 showed the absence of SmeABC but the presence of another putative MDR RND efflux pump, named EbyCAB on a genomic island probably acquired through horizontal gene transfer. PMID:26276674

  10. Biocide and antibiotic susceptibility of Salmonella isolates obtained before and after cleaning at six Danish pig slaughterhouses.

    PubMed

    Gantzhorn, Mette Rørbæk; Pedersen, Karl; Olsen, John Elmerdahl; Thomsen, Line Elnif

    2014-07-01

    Salmonella sp. continues to be one of the most important foodborne pathogens. Control measures in terms of cleaning and disinfection on food production plants are very important for limiting the risk of contaminated food products to reach the consumer. In the last decade concern has arisen that bacteria exposed to disinfectants can develop resistance toward disinfectants and can have a higher risk of developing antibiotic resistance. The objectives of this study were to examine the prevalence of biocide resistant Salmonella sp. in Danish pig slaughterhouses, to evaluate if there was a correlation between susceptibilities to biocides and antibiotics, and to examine if cleaning and disinfection select isolates with changed susceptibility toward biocides or antibiotics. Salmonella sp. was isolated from the environment in Danish pig slaughterhouses before and after cleaning and disinfection. The susceptibility toward three different biocides, triclosan and two commercial disinfection products: Desinfect Maxi, a quaternary ammonium compound, and Incimaxx DES, an acetic compound, was determined. We found no resistance toward the biocides tested, but we did find that isolates obtained after cleaning had higher minimum inhibitory concentration (MIC) values toward one of the disinfectants (Incimaxx DES) compared to isolates obtained before cleaning and disinfection. This could indicate selection of strains that are more tolerant, due to the cleaning and disinfection. Furthermore, we found that there was a weak statistical correlation between MICs toward the biocides and some antibiotics, but no difference in log(MIC)s toward antibiotics between isolates obtained before and after cleaning, nor did we find any difference in the number of resistances of isolates obtained before and after cleaning and disinfection. PMID:24819413

  11. Isolation of Environmental Bacteria from Surface and Drinking Water in Mafikeng, South Africa, and Characterization Using Their Antibiotic Resistance Profiles

    PubMed Central

    Mulamattathil, Suma George; Mbewe, Moses; Ateba, Collins Njie

    2014-01-01

    The aim of this study was to isolate and identify environmental bacteria from various raw water sources as well as the drinking water distributions system in Mafikeng, South Africa, and to determine their antibiotic resistance profiles. Water samples from five different sites (raw and drinking water) were analysed for the presence of faecal indicator bacteria as well as Aeromonas and Pseudomonas species. Faecal and total coliforms were detected in summer in the treated water samples from the Modimola dam and in the mixed water samples, with Pseudomonas spp. being the most prevalent organism. The most prevalent multiple antibiotic resistance phenotype observed was KF-AP-C-E-OT-K-TM-A. All organisms tested were resistant to erythromycin, trimethoprim, and amoxicillin. All isolates were susceptible to ciprofloxacin and faecal coliforms and Pseudomonas spp. to neomycin and streptomycin. Cluster analysis based on inhibition zone diameter data suggests that the isolates had similar chemical exposure histories. Isolates were identified using gyrB, toxA, ecfX, aerA, and hylH gene fragments and gyrB, ecfX, and hylH fragments were amplified. These results demonstrate that (i) the drinking water from Mafikeng contains various bacterial species and at times faecal and total coliforms. (ii) The various bacteria are resistant to various classes of antibiotics. PMID:25105027

  12. A prospective study on evaluation of pathogenesis, biofilm formation, antibiotic susceptibility of microbial community in urinary catheter

    NASA Astrophysics Data System (ADS)

    Younis, Khansa Mohammed; Usup, Gires; Ahmad, Asmat

    2015-09-01

    This study is aimed to isolate, detect biofilm formation ability and antibiotic susceptibility of urinary catheter adherent microorganisms from elderly hospitalized patient at the Universiti Kebangsaan Malaysia Medical Center. Microorganisms were isolated from three samples of urinary catheters (UC) surface; one of the acute vascular rejection patient (UCB) and two from benign prostate hyperplasia patients (UCC and UCD). A total of 100 isolates was isolated with 35 from UCB, 38 (UCC) and 28 (UCD). Ninety six were identified as Gram-negative bacilli, one Gram-positive bacilli and three yeasts. Results of biofilm forming on sterile foley catheter showed that all the isolates can form biofilm at different degrees; strong biofilm forming: 32% from the 35 isolates (UCB), 25% out of 38 isolates (UCC), 26% out of 28 isolates (UCD). As for moderate biofilm forming; 3% from UCB, 10% from UCC and 2% from UCD. Weak biofilm forming in UCC (3%). The antibiotic susceptibility for (UCB) isolates showed highly resistant to ampicillin, novobiocin and penicillin 100 (%), kanamycin (97%), tetracycline (94%), chloramphenicol (91%), streptomycin (77%) and showed low level of resistance to gentamycin (17%), while all the isolates from (UCC-D) showed high resistant towards ampicillin and penicillin, novobiocin (94%), tetracycline (61%), streptomycin (53%), gentamycin (50%) and low level of resistance to kanamycin (48%), chloramphenicol (47%). The findings indicate that these isolates can spread within the community on urinary catheters surface and produce strong biofilm, therefore, monitoring antibiotic susceptibility of bacteria isolated in the aggregation is recommended.

  13. Changes in antibiotic usage and susceptibility in nosocomial Enterobacteriaceae and Pseudomonas isolates following the introduction of ertapenem to hospital formulary.

    PubMed

    Graber, C J; Hutchings, C; Dong, F; Lee, W; Chung, J K; Tran, T

    2012-01-01

    There is concern that widespread usage of ertapenem may promote cross-resistance to other carbapenems. To analyse the impact that adding ertapenem to our hospital formulary had on usage of other broad-spectrum agents and on susceptibilities of nosocomial Enterobacteriaceae and Pseudomonas isolates, we performed interrupted time-series analyses to determine the change in linear trend in antibiotic usage and change in mean proportion and linear trend of susceptibility pre- (March 2004-June 2005) and post- (July 2005-December 2008) ertapenem introduction. Usage of piperacillin-tazobactam (P=0·0013) and ampicillin-sulbactam (P=0·035) declined post-ertapenem introduction. For Enterobacteriaceae, the mean proportion susceptible to ciprofloxacin (P=0·016) and piperacillin-tazobactam (P=0·038) increased, while the linear trend in susceptibility significantly increased for cefepime (P=0·012) but declined for ceftriaxone (P=0·0032). For Pseudomonas, the mean proportion susceptible to cefepime (P=0·011) and piperacillin-tazobactam (P=0·028) increased, as did the linear trend in susceptibility to ciprofloxacin (P=0·028). Notably, no significant changes in carbapenem susceptibility were observed. PMID:21303590

  14. Genetic risk profiles for cancer susceptibility and therapy response.

    PubMed

    Bartsch, Helmut; Dally, Heike; Popanda, Odilia; Risch, Angela; Schmezer, Peter

    2007-01-01

    Cells in the body are permanently attacked by DNA-reactive species, both from intracellular and environmental sources. Inherited and acquired deficiencies in host defense mechanisms against DNA damage (metabolic and DNA repair enzymes) can modify cancer susceptibility as well as therapy response. Genetic profiles should help to identify high-risk individuals who subsequently can be enrolled in preventive measures or treated by tailored therapy regimens. Some of our attempts to define such risk profiles are presented. Cancer susceptibility: Single nucleotide polymorphisms (SNPs) in metabolic and repair genes were investigated in a hospital-based lung cancer case-control study. When evaluating the risk associated with different genotypes for N-acetyltransferases (Wikman et al. 2001) and glutathione-S-transferases (Risch et al. 2001), it is mandatory to distinguish between the three major histological subtypes of lung tumors. A promoter polymorphism of the myeloperoxidase gene MPO was shown to decrease lung cancer susceptibility mainly in small cell lung cancer (SCLC) (Dally et al. 2002). The CYP3A4*1B allele was also linked to an increased SCLC risk and in smoking women increased the risk of lung cancer eightfold (Dally et al. 2003b). Polymorphisms in DNA repair genes were shown to modulate lung cancer risk in smokers, and reduced DNA repair capacity elevated the disease risk (Rajaee-Behbahani et al. 2001). Investigations of several DNA repair gene variants revealed that lung cancer risk was only moderately affected by a single variant but was enhanced up to approximately threefold by specific risk allele combinations (Popanda et al. 2004). Therapy response: Inter-individual differences in therapy response are consistently observed with cancer chemotherapeutic agents. Initial results from ongoing studies showed that certain polymorphisms in drug transporter genes (ABCB1) differentially affect response outcome in histological subgroups of lung cancer. Stronger

  15. Screening of antibiotic susceptibility to β-lactam-induced elongation of Gram-negative bacteria based on dielectrophoresis.

    PubMed

    Chung, Cheng-Che; Cheng, I-Fang; Chen, Hung-Mo; Kan, Heng-Chuan; Yang, Wen-Horng; Chang, Hsien-Chang

    2012-04-01

    We demonstrate a rapid antibiotic susceptibility test (AST) based on the changes in dielectrophoretic (DEP) behaviors related to the β-lactam-induced elongation of Gram-negative bacteria (GNB) on a quadruple electrode array (QEA). The minimum inhibitory concentration (MIC) can be determined within 2 h by observing the changes in the positive-DEP frequency (pdf) and cell length of GNB under the cefazolin (CEZ) treatment. Escherichia coli and Klebsiella pneumoniae and the CEZ are used as the sample bacteria and antibiotic respectively. The bacteria became filamentous due to the inhibition of cell wall synthesis and cell division and cell lysis occurred for the higher antibiotic dose. According to the results, the pdfs of wild type bacteria decrease to hundreds of kHz and the cell length is more than 10 μm when the bacterial growth is inhibited by the CEZ treatment. In addition, the growth of wild type bacteria and drug resistant bacteria differ significantly. There is an obvious decrease in the number of wild type bacteria but not in the number of drug resistant bacteria. Thus, the drug resistance of GNB to β-lactam antibiotics can be rapidly assessed. Furthermore, the MIC determined using dielectrophoresis-based AST (d-AST) was consistent with the results of the broth dilution method. Utilizing this approach could reduce the time needed for bacteria growth from days to hours, help physicians to administer appropriate antibiotic dosages, and reduce the possibility of the occurrence of multidrug resistant (MDR) bacteria. PMID:22404714

  16. [Susceptibility rate to tigecycline and antibiotic-resistance among Klebsiella pneumoniae strains isolated in Intensive Care Unit].

    PubMed

    Buccoliero, Giovanni; Morelli, Elisabetta; Romanelli, Chiara; Lonero, Gaetano; Pisconti, Salvatore; Resta, Francesco

    2012-01-01

    Antibiotic resistance in Klebsiella pneumoniae strains is an increasing problem in a lot of hospitals. It is a public health emergency because it relates with high mortality rate among patients in Intensive Care Unit (ICU). From 1/1/2009 to 31/08/2010, in ICU of SS Annunziata Hospital of Taranto, 140 isolated Klebsiella pneumoniae strains were detected. The strain identification and antimicrobial susceptibility testing were performed using a Vitek2 automated system. These isolate showed a low level of susceptibility to levofloxacin (3.4%), ciprofloxacin (6.2%), ceftazidime (2.8%) and piperacillin/tazobactam (8%). We reported also that the 10% and 13.9% of them were susceptible to meropenem and imipenem. An anti-Klebsiella pneumoniae activity in vitro to tigecycline was present in 64.6% of isolates while almost all strains (56/58) tested to colistin were susceptible. In order to our data of worryng high multiclass drug resistance including tygecicline, it needs to apply appropriate measures of surveillance and antibiotic prescription to avoid rapid spread of these mutiresistant strains in other areas. PMID:22825382

  17. Molecular typing and differences in biofilm formation and antibiotic susceptibilities among Prototheca strains isolated in Italy and Brazil.

    PubMed

    Morandi, S; Cremonesi, P; Capra, E; Silvetti, T; Decimo, M; Bianchini, V; Alves, A C; Vargas, A C; Costa, G M; Ribeiro, M G; Brasca, M

    2016-08-01

    Bovine mastitis caused by Prototheca is a serious and complex problem that accounts for high economic losses in the dairy industry. The main objective of this study was to identify and characterize at genetic level different Prototheca strains and provide the most complete data about protothecal antibiotic resistance. The study involves 46 isolates from Italian (13 strains) and Brazilian (33 strains) mastitic milk. These strains were identified by multiplex PCR and single strand conformation polymorphism analysis and characterized by randomly amplified polymorphic DNA (RAPD)-PCR. Moreover, biofilm production and antibiotic susceptibility were evaluated. Forty-two strains resulted as Prototheca zopfii genotype 2, whereas 4 isolates could belong to a potential new Prototheca species. The RAPD-PCR, performed with 3 primers (M13, OPA-4, and OPA-18), showed a notable heterogeneity among isolates and grouped the strains according to the species and geographical origin. Biofilm production was species-dependent and P. zopfii genotype 2 strains were classified as strong biofilm producers. In vitro antibiotic susceptibility tests indicated that Prototheca strains were susceptible to antibacterial drugs belonging to aminoglycosides group; the highest activity against Prototheca strains was observed in the case of colistin sulfate, gentamicin, and netilmicin (100% of susceptible strains). It is interesting to note that all the Italian P. zopfii genotype 2 strains showed lower minimum inhibitory concentration values than the Brazilian ones. Nisin showed more efficacy than lysozyme and potassium sorbate, inhibiting 31% of the strains. Results obtained in this study confirmed that RAPD-PCR is a rapid, inexpensive, and highly discriminating tool for Prototheca strains characterization and could give a good scientific contribution for better understanding the protothecal mastitis in dairy herd. PMID:27236754

  18. Characterization of Pre-Antibiotic Era Klebsiella pneumoniae Isolates with Respect to Antibiotic/Disinfectant Susceptibility and Virulence in Galleria mellonella

    PubMed Central

    Baker, Kate S.; Benthall, Gabriel; McGregor, Hannah; McCowen, James W. I.; Deheer-Graham, Ana; Sutton, J. Mark

    2015-01-01

    The EGD Murray collection consists of approximately 500 clinical bacterial isolates, mainly Enterobacteriaceae, isolated from around the world between 1917 and 1949. A number of these “Murray” isolates have subsequently been identified as Klebsiella pneumoniae. Antimicrobial susceptibility testing of these isolates showed that over 30% were resistant to penicillins due to the presence of diverse blaSHV β-lactamase genes. Analysis of susceptibility to skin antiseptics and triclosan showed that while the Murray isolates displayed a range of MIC/minimal bactericidal concentration (MBC) values, the mean MIC value was lower than that for more modern K. pneumoniae isolates tested. All Murray isolates contained the cation efflux gene cepA, which is involved in disinfectant resistance, but those that were more susceptible to chlorhexidine were found to have a 9- or 18-bp insertion in this gene. Susceptibility to other disinfectants, e.g., H2O2, in the Murray isolates was comparable to that in modern K. pneumoniae isolates. The Murray isolates were also less virulent in Galleria and had a different complement of putative virulence factors than the modern isolates, with the exception of an isolate related to the modern lineage CC23. More of the modern isolates (41% compared to 8%) are classified as good/very good biofilm formers, but there was overlap in the two populations. This study demonstrated that a significant proportion of the Murray Klebsiella isolates were resistant to penicillins before their routine use. This collection of pre-antibiotic era isolates may provide significant insights into adaptation in K. pneumoniae in relation to biocide susceptibility. PMID:25896708

  19. Characterization of pre-antibiotic era Klebsiella pneumoniae isolates with respect to antibiotic/disinfectant susceptibility and virulence in Galleria mellonella.

    PubMed

    Wand, Matthew E; Baker, Kate S; Benthall, Gabriel; McGregor, Hannah; McCowen, James W I; Deheer-Graham, Ana; Sutton, J Mark

    2015-07-01

    The EGD Murray collection consists of approximately 500 clinical bacterial isolates, mainly Enterobacteriaceae, isolated from around the world between 1917 and 1949. A number of these "Murray" isolates have subsequently been identified as Klebsiella pneumoniae. Antimicrobial susceptibility testing of these isolates showed that over 30% were resistant to penicillins due to the presence of diverse blaSHV β-lactamase genes. Analysis of susceptibility to skin antiseptics and triclosan showed that while the Murray isolates displayed a range of MIC/minimal bactericidal concentration (MBC) values, the mean MIC value was lower than that for more modern K. pneumoniae isolates tested. All Murray isolates contained the cation efflux gene cepA, which is involved in disinfectant resistance, but those that were more susceptible to chlorhexidine were found to have a 9- or 18-bp insertion in this gene. Susceptibility to other disinfectants, e.g., H2O2, in the Murray isolates was comparable to that in modern K. pneumoniae isolates. The Murray isolates were also less virulent in Galleria and had a different complement of putative virulence factors than the modern isolates, with the exception of an isolate related to the modern lineage CC23. More of the modern isolates (41% compared to 8%) are classified as good/very good biofilm formers, but there was overlap in the two populations. This study demonstrated that a significant proportion of the Murray Klebsiella isolates were resistant to penicillins before their routine use. This collection of pre-antibiotic era isolates may provide significant insights into adaptation in K. pneumoniae in relation to biocide susceptibility. PMID:25896708

  20. Mutations in the Primary Sigma Factor σA and Termination Factor Rho That Reduce Susceptibility to Cell Wall Antibiotics

    PubMed Central

    Lee, Yong Heon

    2014-01-01

    Combinations of glycopeptides and β-lactams exert synergistic antibacterial activity, but the evolutionary mechanisms driving resistance to both antibiotics remain largely unexplored. By repeated subculturing with increasing vancomycin (VAN) and cefuroxime (CEF) concentrations, we isolated an evolved strain of the model bacterium Bacillus subtilis with reduced susceptibility to both antibiotics. Whole-genome sequencing revealed point mutations in genes encoding the major σ factor of RNA polymerase (sigA), a cell shape-determining protein (mreB), and the ρ termination factor (rho). Genetic-reconstruction experiments demonstrated that the G-to-C substitution at position 336 encoded by sigA (sigAG336C), in the domain that recognizes the −35 promoter region, is sufficient to reduce susceptibility to VAN and works cooperatively with the rhoG56C substitution to increase CEF resistance. Transcriptome analyses revealed that the sigAG336C substitution has wide-ranging effects, including elevated expression of the general stress σ factor (σB) regulon, which is required for CEF resistance, and decreased expression of the glpTQ genes, which leads to fosfomycin (FOS) resistance. Our findings suggest that mutations in the core transcriptional machinery may facilitate the evolution of resistance to multiple cell wall antibiotics. PMID:25112476

  1. Typhoid Fever in Young Children in Bangladesh: Clinical Findings, Antibiotic Susceptibility Pattern and Immune Responses

    PubMed Central

    Khanam, Farhana; Sayeed, Md. Abu; Choudhury, Feroza Kaneez; Sheikh, Alaullah; Ahmed, Dilruba; Goswami, Doli; Hossain, Md. Lokman; Brooks, Abdullah; Calderwood, Stephen B.; Charles, Richelle C.; Cravioto, Alejandro; Ryan, Edward T.; Qadri, Firdausi

    2015-01-01

    Background Children bear a large burden of typhoid fever caused by Salmonella enterica serotype Typhi (S. Typhi) in endemic areas. However, immune responses and clinical findings in children are not well defined. Here, we describe clinical and immunological characteristics of young children with S. Typhi bacteremia, and antimicrobial susceptibility patterns of isolated strains. Methods As a marker of recent infection, we have previously characterized antibody-in-lymphocyte secretion (TPTest) during acute typhoid fever in adults. We similarly assessed membrane preparation (MP) IgA responses in young children at clinical presentation, and then 7-10 days and 21-28 days later. We also assessed plasma IgA, IgG and IgM responses and T cell proliferation responses to MP at these time points. We compared responses in young children (1-5 years) with those seen in older children (6-17 years), adults (18-59 years), and age-matched healthy controls. Principal Findings We found that, compared to age-matched controls patients in all age cohorts had significantly more MP-IgA responses in lymphocyte secretion at clinical presentation, and the values fell in all groups by late convalescence. Similarly, plasma IgA responses in patients were elevated at presentation compared to controls, with acute and convalescent IgA and IgG responses being highest in adults. T cell proliferative responses increased in all age cohorts by late convalescence. Clinical characteristics were similar in all age cohorts, although younger children were more likely to present with loss of appetite, less likely to complain of headache compared to older cohorts, and adults were more likely to have ingested antibiotics. Multi-drug resistant strains were present in approximately 15% of each age cohort, and 97% strains had resistance to nalidixic acid. Conclusions This study demonstrates that S. Typhi bacteremia is associated with comparable clinical courses, immunologic responses in various age cohorts

  2. Stability of frozen stock solutions of beta-lactam antibiotics, cephalosporins, tetracyclines and quinolones used in antibiotic residue screening and antibiotic susceptibility testing.

    PubMed

    Okerman, Lieve; Van Hende, Johan; De Zutter, Lieven

    2007-03-14

    The stability of frozen stock solutions of antibiotics belonging to three different families was evaluated using an agar diffusion test, with Bacillus subtilis as a test strain. Diameters of inhibition zones were measured at monthly intervals during 6 months, and the decline in active substance was calculated. Penicillin and amoxicillin lost nearly half of their potency, the cephalosporins ceftiofur and cefapirin one quarter, but ampicillin was more stable. The quinolones flumequine, enrofloxacin and marbofloxacin were relatively stable; the loss of activity was less than 10% after 6 months of preservation at -20 degrees C. This was also the case for doxycycline and chlortetracycline, while oxytetracycline and tetracycline lost about 25% of their potency. When used in microbiology, i.e. for residue testing or for determination of minimum inhibitory concentrations, a diminution of activity less than 25% will not be noticed. For these applications, the four tetracyclines and three quinolones tested can be kept for 6 months at -20 degrees C, while the beta-lactam antibiotics should be discarded after 3 months. Standard stock solutions of beta-lactam antibiotics and cephalosporins should preferably be used the same day when they are intended for quantitative residue analysis. PMID:17386725

  3. Correlation of penicillinase production with phage type and susceptibility to antibiotics and heavy metals in Staphylococcus aureus.

    PubMed

    Rosdahl, V T; Rosendal, K

    1983-11-01

    One hundred and thirty-nine bacteraemia strains of Staphylococcus aureus, representing different combinations of phage type and susceptibility to antibiotics and to cadmium (Cd), arsenate (As) and mercury (Hg), were investigated for penicillinase production. The determination of enzyme activity in induced and uninduced conditions was performed by iodometric titration. The amount of penicillinase produced could be correlated with phage pattern. Epidemically occurring strains of the 94,96 and the 83A complexes produced the largest amount of penicillinase, whereas strains of the 52,52A,80,81 complex were weaker producers. Group-II and group-III strains produced the smallest amount. Susceptibility to antibiotics and to Cd, As and Hg could not be correlated with enzyme activity, but strains resistant to penicillin plus tetracyclines and strains resistant only to Cd did produce less enzyme than strains with other resistance patterns. The percentage mean values than strains with other resistance patterns. The percentage mean values of extracellularity of the enzyme was highest amongst strains of the 94,96 complex and of type 95. Four strains had constitutive production, one being macro-constitutive and three micro-constitutive. All four strains represented rare combinations of the above properties but were susceptible to fusidic acid. The importance of penicillinase production by epidemically occurring strains is discussed. PMID:6227749

  4. Antibiotic susceptibility of members of the Lactobacillus acidophilus group using broth microdilution and molecular identification of their resistance determinants.

    PubMed

    Mayrhofer, Sigrid; van Hoek, Angela H A M; Mair, Christiane; Huys, Geert; Aarts, Henk J M; Kneifel, Wolfgang; Domig, Konrad J

    2010-11-15

    The range of antibiotic susceptibility to 13 antibiotics in 101 strains of the Lactobacillus acidophilus group was examined using the lactic acid bacteria susceptibility test medium (LSM) and broth microdilution. Additionally, microarray analysis and PCR were applied to identify resistance genes responsible for the displayed resistant phenotypes in a selection of strains. In general, narrow as well as broad unimodal and bimodal MIC distributions were observed for the Lactobacillus acidophilus group and the tested antimicrobial agents. Atypically resistant strains could be determined by visual inspection of the obtained MIC ranges for ampicillin, chloramphenicol, clindamycin, erythromycin, quinupristin/dalfopristin, streptomycin and tetracycline. For most of these atypically resistant strains underlying resistance determinants were found. To our knowledge erm(A) was detected in lactobacilli for the first time within this study. Data derived from this study can be used as a basis for reviewing present microbiological breakpoints for categorization of susceptible and resistant strains within the Lactobacillus acidophilus group to assess the safety of microorganisms intended for use in food and feed applications. PMID:20888656

  5. Incidence and antibiotic susceptibility of Mycoplasma hominis and Ureaplasma urealyticum isolated in Brescia, Italy, over 7 years.

    PubMed

    De Francesco, Maria Antonia; Caracciolo, Sonia; Bonfanti, Carlo; Manca, Nino

    2013-08-01

    The prevalence and antimicrobial susceptibility of Ureaplasma urealyticum and Mycoplasma hominis collected during 2004-2011 were determined. A total of 9956 individuals was analyzed. Identification was performed by use of the mycoplasma IST-2 kit. Antimicrobial susceptibility against doxycycline, josamycin, ofloxacin, erythromycin, tetracycline, ciprofloxacin, azithromycin, clarithromycin, and pristinamycin was also tested by use of this commercial kit. Our results show a prevalence of 1856 positive patients for genital mycoplasmas (18.6 %). Among positive cultures, 89 and 1.1 % of isolates were Ureaplasma urealyticum and Mycoplasma hominis, respectively. For 9.8 % of isolates both urogenital mycoplasmas were grown. Doxycycline was the most active tetracycline for mycoplasma infections, and this is still the drug of first choice. Among macrolides, josamycin and clarithromycin are the most active agents against ureaplasmas; josamycin is also active against mycoplasmas and is an alternative to tetracyclines and erythromycin for mixed infections, especially for pregnant women and neonates. Fluoroquinolones had low efficacy against urogenital mycoplasmas. For Ureaplasma urealyticum, cross-resistance was found between erythromycin and macrolides (except josamycin) (40-80 %) and between erythromycin and ciprofloxacin (79 %). Antibiotic resistance over the test period did not vary significantly. Because of geographical differences among antibiotic resistance, local in-vitro susceptibility testing is recommended to avoid failure of therapy. PMID:23192735

  6. Microarray-based long oligonucleotides probe designed for Brucella Spp. detection and identification of antibiotic susceptibility pattern

    PubMed Central

    Khazaei, Zahra; Najafi, Ali; Piranfar, Vahhab; Mirnejad, Reza

    2016-01-01

    Brucella spp. is a common zoonotic infection referred to as Brucellosis, and it is a serious public health problem around the world. There are currently six classical species (pathogenic species in both animals and humans) within the genus Brucella. The ability and practicality facilitated by a microarray experiment help us to recognize Brucella spp. and its antibiotic resistant gene. Rapid phenotypic determination of antibiotic resistance is not possible by disk diffusion methods. Thus, evaluating antibiotics pattern and Brucella detection appear necessary technique by molecular methods in brucellosis. So, the aim of this study was to design a microarray long oligonucleotides probe and primer for the complete diagnosis of Brucella spp. and obtaining genetic profiles for antibiotic resistance in bacteria at the same time. In this study, we designed 16 antibiotic-resistant gene solid-phase primers with similar melting temperatures of 60 °C and 16 long oligonucleotide probes. These primers and probes can identify tetracycline-, chloramphenicol-, and aminoglycoside-resistant genes, respectively. The design of microarray probes is a versatile process that be done in a wide range of selections. Since the long oligo microarray probes are the best choices for specific diagnosis and definite treatment, this group of probes was designed in the present survey. PMID:27280008

  7. Microarray-based long oligonucleotides probe designed for Brucella Spp. detection and identification of antibiotic susceptibility pattern.

    PubMed

    Khazaei, Zahra; Najafi, Ali; Piranfar, Vahhab; Mirnejad, Reza

    2016-04-01

    Brucella spp. is a common zoonotic infection referred to as Brucellosis, and it is a serious public health problem around the world. There are currently six classical species (pathogenic species in both animals and humans) within the genus Brucella. The ability and practicality facilitated by a microarray experiment help us to recognize Brucella spp. and its antibiotic resistant gene. Rapid phenotypic determination of antibiotic resistance is not possible by disk diffusion methods. Thus, evaluating antibiotics pattern and Brucella detection appear necessary technique by molecular methods in brucellosis. So, the aim of this study was to design a microarray long oligonucleotides probe and primer for the complete diagnosis of Brucella spp. and obtaining genetic profiles for antibiotic resistance in bacteria at the same time. In this study, we designed 16 antibiotic-resistant gene solid-phase primers with similar melting temperatures of 60 °C and 16 long oligonucleotide probes. These primers and probes can identify tetracycline-, chloramphenicol-, and aminoglycoside-resistant genes, respectively. The design of microarray probes is a versatile process that be done in a wide range of selections. Since the long oligo microarray probes are the best choices for specific diagnosis and definite treatment, this group of probes was designed in the present survey. PMID:27280008

  8. Antibiotics.

    PubMed

    Hariprasad, Seenu M; Mieler, William F

    2016-01-01

    The Endophthalmitis Vitrectomy Study (EVS) provided ophthalmologists with evidence-based management strategies to deal with endophthalmitis for the first time. However, since the completion of the EVS, numerous unresolved issues remain. The use of oral antibiotics has important implications for the ophthalmologist, particularly in the prophylaxis and/or management of postoperative, posttraumatic, or bleb-associated bacterial endophthalmitis. One can reasonably conclude that significant intraocular penetration of an antibiotic after oral administration may be a property unique to the newer-generation fluoroquinolones. Prophylactic use of mupirocin nasal ointment resulted in significant reduction of conjunctival flora with or without preoperative topical 5% povidone-iodine preparation. Ocular fungal infections have traditionally been very difficult to treat due to limited therapeutic options both systemically and intravitreally. Because of its broad spectrum of coverage, low MIC90 levels for the organisms of concern, good tolerability, and excellent bioavailability, voriconazole through various routes of administration may be useful to the ophthalmologist in the primary treatment of or as an adjunct to the current management of ocular fungal infections. PMID:26501865

  9. Metabolic Profiling for Detection of Staphylococcus aureus Infection and Antibiotic Resistance

    PubMed Central

    Näsström, Elin; Kouremenos, Konstantinos; Sundén-Cullberg, Jonas; Guo, YongZhi; Moritz, Thomas; Wolf-Watz, Hans; Johansson, Anders; Fallman, Maria

    2013-01-01

    Due to slow diagnostics, physicians must optimize antibiotic therapies based on clinical evaluation of patients without specific information on causative bacteria. We have investigated metabolomic analysis of blood for the detection of acute bacterial infection and early differentiation between ineffective and effective antibiotic treatment. A vital and timely therapeutic difficulty was thereby addressed: the ability to rapidly detect treatment failures because of antibiotic-resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) were used in vitro and for infecting mice, while natural MSSA infection was studied in humans. Samples of bacterial growth media, the blood of infected mice and of humans were analyzed with combined Gas Chromatography/Mass Spectrometry. Multivariate data analysis was used to reveal the metabolic profiles of infection and the responses to different antibiotic treatments. In vitro experiments resulted in the detection of 256 putative metabolites and mice infection experiments resulted in the detection of 474 putative metabolites. Importantly, ineffective and effective antibiotic treatments were differentiated already two hours after treatment start in both experimental systems. That is, the ineffective treatment of MRSA using cloxacillin and untreated controls produced one metabolic profile while all effective treatment combinations using cloxacillin or vancomycin for MSSA or MRSA produced another profile. For further evaluation of the concept, blood samples of humans admitted to intensive care with severe sepsis were analyzed. One hundred thirty-three putative metabolites differentiated severe MSSA sepsis (n = 6) from severe Escherichia coli sepsis (n = 10) and identified treatment responses over time. Combined analysis of human, in vitro, and mice samples identified 25 metabolites indicative of effective treatment of S. aureus sepsis. Taken together, this study provides a

  10. Antibiotic susceptibility and molecular epidemiology of Acinetobacter calcoaceticus–baumannii complex strains isolated from a referral hospital in northern Vietnam

    PubMed Central

    Van, Trang Dinh; Dinh, Quynh-Dao; Vu, Phu Dinh; Nguyen, Trung Vu; Pham, Ca Van; Dao, Trinh Tuyet; Phung, Cam Dac; Hoang, Ha Thu Thi; Tang, Nga Thi; Do, Nga Thuy; Nguyen, Kinh Van; Wertheim, Heiman

    2014-01-01

    Acinetobacter calcoaceticus–baumannii complex is a common cause of hospital-acquired infections (HAIs) globally, remarkable for its high rate of antibiotic resistance, including to carbapenems. There are few data on the resistance of A. baumannii in Vietnam, which are essential for developing evidence-based treatment guidelines for HAIs. Antibiotic susceptibility testing was conducted by VITEK®2, and pulsed-field gel electrophoresis (PFGE) was performed on 66 clinical A. baumannii complex isolates recovered during 2009 at the National Hospital of Tropical Diseases (NHTD), a referral hospital in Hanoi, Vietnam. Basic demographic and clinical data were collected and analysed using descriptive statistics. Most isolates came from lower respiratory tract specimens (59; 89.4%) from intensive care unit (ICU) patients [64/65 (98.5%) with available data] who had been admitted to NHTD for ≥2 days [42/46 (91.3%) with available data]. More than 90% of the isolates were resistant to the tested β-lactamase/β-lactamase inhibitors, cephalosporins, carbapenems, fluoroquinolones and trimethoprim/sulfamethoxazole. Moreover, 25.4% (16/63) were resistant to all tested β-lactams, quinolones and aminoglycosides. All isolates remained sensitive to colistin and 58.7% were susceptible to tigecycline. Of the 66 isolates, 49 could be classified into eight PFGE types (A–H). Every PFGE type, except D, had cluster(s) of three or more isolates with a temporal relationship. In conclusion, these data suggest a significant rise in A. baumannii antibiotic resistance in Vietnam. Clustering within PFGE types supports cross-transmission of A. baumannii within the ICU at NHTD. Increased research and resources in optimising treatment, infection control and antibiotic stewardship are needed. PMID:25540720

  11. Impact of microbiology cascade reporting on antibiotic de-escalation in cefazolin-susceptible Gram-negative bacteremia.

    PubMed

    Johnson, L S; Patel, D; King, E A; Maslow, J N

    2016-07-01

    Cascade reporting (CR) involves reporting the susceptibilities of broad-spectrum agents only when the organism is resistant to more narrow-spectrum agents. The purpose of this study is to evaluate the impact of CR on antibiotic de-escalation practices and to characterize the impact of CR on clinical outcomes. CR rules were implemented in the microbiology laboratory at Atlantic Health System (AHS) in June 2013. A retrospective chart review was conducted at two community teaching hospitals in adult patients who had a blood culture positive for a Gram-negative organism susceptible to cefazolin and who were empirically treated with broad-spectrum beta-lactam (BSBL) antibiotics. De-escalation practices were compared in the pre-CR (July 2012-December 2012) and post-CR (July 2013-December 2013) periods. The primary endpoint was the percentage of patients whose BSBL agent was de-escalated to agents listed on the post-CR antibiotic susceptibility report within 48 h of the final report. Secondary endpoints include the difference in pre-CR and post-CR periods in terms of hospital length of stay, in-hospital mortality, 30-day readmission, Clostridium difficile infections, and re-initiation of a BSBL agent within 7 days. A total of 73 patients were included; 31 in the pre-CR and 42 in the post-CR period. Patients had similar baseline characteristics. Therapy was de-escalated in 48 % of pre-CR vs 71 % of post-CR patients (p = 0.043). No significant differences were observed in secondary endpoints between patients in the pre-CR and post-CR periods. CR resulted in significant improvements in de-escalation practices without affecting safety outcomes. PMID:27130036

  12. Antibiotic susceptibility and molecular mechanisms of macrolide resistance in streptococci isolated from adult cystic fibrosis patients.

    PubMed

    Thornton, Christina S; Grinwis, Margot E; Sibley, Christopher D; Parkins, Michael D; Rabin, Harvey R; Surette, Michael G

    2015-11-01

    The cystic fibrosis (CF) airways are colonized by polymicrobial communities with high bacterial load and are influenced by frequent antibiotic exposures. This community includes diverse streptococci, some of which have been directly or indirectly associated with pulmonary exacerbations. As many streptococci are naturally competent, horizontal transfer of antibiotic-resistant determinants coupled with frequent and/or chronic antibiotic exposure may contribute to high resistance rates. In this study, we assessed antibiotic resistance in 413 streptococcal isolates from adult CF patients against nine antibiotics relevant in CF treatment. We observed very low rates of cephalosporin resistance [cefepime and ceftriaxone ( < 2%)], and higher rates of resistance to tetracycline (∼34%) and sulfamethoxazole/trimethoprim (∼45%). The highest rate of antibiotic resistance was to the macrolides [azithromycin (56.4%) and erythromycin (51.6%)]. We also investigated the molecular mechanisms of macrolide resistance and found that only half of our macrolide-resistant streptococci isolates contained the mef (efflux pump) or erm (methylation of 23S ribosomal target site) genes. The majority of isolates were, however, found to have point mutations at position 2058 or 2059 of the 23S ribosomal subunit - a molecular mechanism of resistance not commonly reported in the non-pyogenic and non-pneumococcal streptococci, and unique in comparison with previous studies. The high rates of resistance observed here may result in poor outcomes where specific streptococci are contributing to CF airway disease and serve as a reservoir of resistance genes within the CF airway microbiome. PMID:26408040

  13. Pathogenic bacteria profile and antimicrobial susceptibility patterns of ear infection at Bahir Dar Regional Health Research Laboratory Center, Ethiopia.

    PubMed

    Hailu, Derese; Mekonnen, Daniel; Derbie, Awoke; Mulu, Wondemagegn; Abera, Bayeh

    2016-01-01

    Ear infection linked with frequent antibiotic prescription, hearing impairment, severe disability and death is a public health threat in developing countries. However, there is scarcity of documented data in the study area. Therefore, this study aimed at determining bacterial etiologic agents and their antimicrobial susceptibility patterns among patients of all age groups referred to Bahir Dar Regional Health Research Laboratory Center. Retrospective data recorded on culture and antimicrobial susceptibility profile were retrieved for analysis. Pus swabs from discharging ears collected and processed for aerobic bacteria culture and susceptibility testing. Of the total 368 pus swab samples processed, 296 (80.4 %) were culture positive. Of which, 289 (97.6 %) were bacteria and 7 (2.4 %) were yeast cells. The proportion of ear infection was higher in males (92.7 %) than females (65 %) (P = 0.014). The frequency of ear infection below 21 years of age was 65.2 %. The predominant isolate was Pseudomonas aeruginosa (29.7 %) followed by Staphylococcus aureus (26.3 %) and Proteus spp. (21.9 %). High level of antimicrobial resistance rates were observed for amoxicillin/clavulanic acid, ampicillin and penicillin whereas ciprofloxacin, ceftriaxone, chloramphenicol, cotrimoxazole, gentamicin and amikacin were found effective against the isolated bacteria. Aerobic bacterial otitis media linked with high levels of resistance against amoxicillin/clavulanic acid and ampicillin is major health problem in the study area. Moreover, considerable level of oxacillin resistant S. aureus suggests the diffusion of methicillin resistant S. aureus in the community. Therefore, treatment of otitis media in the study area needs to be guided by antibiotic susceptibility testing of isolates. PMID:27119070

  14. Susceptibility of avian pathogenic Escherichia coli from laying hens in Belgium to antibiotics and disinfectants and integron prevalence.

    PubMed

    Oosterik, Leon H; Peeters, Laura; Mutuku, Irene; Goddeeris, Bruno M; Butaye, Patrick

    2014-06-01

    Avian pathogenic Escherichia coli (APEC) causes huge annual losses in the poultry industry worldwide. Multiresistance against antibiotics of APEC strains is increasingly seen in broilers, although much is still unknown about strains from laying hens where use of antibiotics is limited. Disinfection can reduce the infection burden. However, little is known about the presence of resistance against these products. Ninety-seven APEC strains were isolated from Belgian laying hens. The resistance to different classes of antibiotics was determined as well as the minimum inhibitory concentrations (MIC; agar and broth dilution) and minimum bactericidal concentrations (MBC) of five disinfectants most often used in the poultry industry (formaldehyde, glutaraldehyde, glyoxal, hydrogen peroxide, and a quaternary ammonium compound). The presence of integrons was determined by PCR Resistance to ampicillin (35.1%), nalidixic acid (38.1%), sulfonamides (SULFA, 41.2%), and tetracycline (TET, 53.6%) was high but resistance to other tested antibiotics was low. Nevertheless, two extended spectrum beta-lactamase producers were found. The MIC of the disinfectants for the APEC strains showed a Gaussian distribution, indicating that there was no acquired resistance. MBCs were similar to MICs via the broth dilution method, showing the bactericidal effect of the disinfectants. Twenty-one strains (21.6%) were found positive for class 1 integrons and a positive association between integron presence and resistance to trimethoprim, SULFA, and TET was found. No association could be found between integron presence and phylogenetic group affiliation. Susceptibility of APEC strains from laying hens to antibiotics is, in general, very high. Phenotypic resistance to commonly used disinfectants could not be found, indicating that the current use of disinfectants in the laying hen industry did not select for resistance. PMID:25055632

  15. Virulence Factors and Antibiotic Susceptibility of Staphylococcus aureus Isolates in Ready-to-Eat Foods: Detection of S. aureus Contamination and a High Prevalence of Virulence Genes

    PubMed Central

    Puah, Suat Moi; Chua, Kek Heng; Tan, Jin Ai Mary Anne

    2016-01-01

    Staphylococcus aureus is one of the leading causes of food poisoning. Its pathogenicity results from the possession of virulence genes that produce different toxins which result in self-limiting to severe illness often requiring hospitalization. In this study of 200 sushi and sashimi samples, S. aureus contamination was confirmed in 26% of the food samples. The S. aureus isolates were further characterized for virulence genes and antibiotic susceptibility. A high incidence of virulence genes was identified in 96.2% of the isolates and 20 different virulence gene profiles were confirmed. DNA amplification showed that 30.8% (16/52) of the S. aureus carried at least one SE gene which causes staphylococcal food poisoning. The most common enterotoxin gene was seg (11.5%) and the egc cluster was detected in 5.8% of the isolates. A combination of hla and hld was the most prevalent coexistence virulence genes and accounted for 59.6% of all isolates. Antibiotic resistance studies showed tetracycline resistance to be the most common at 28.8% while multi-drug resistance was found to be low at 3.8%. In conclusion, the high rate of S. aureus in the sampled sushi and sashimi indicates the need for food safety guidelines. PMID:26861367

  16. Virulence Factors and Antibiotic Susceptibility of Staphylococcus aureus Isolates in Ready-to-Eat Foods: Detection of S. aureus Contamination and a High Prevalence of Virulence Genes.

    PubMed

    Puah, Suat Moi; Chua, Kek Heng; Tan, Jin Ai Mary Anne

    2016-02-01

    Staphylococcus aureus is one of the leading causes of food poisoning. Its pathogenicity results from the possession of virulence genes that produce different toxins which result in self-limiting to severe illness often requiring hospitalization. In this study of 200 sushi and sashimi samples, S. aureus contamination was confirmed in 26% of the food samples. The S. aureus isolates were further characterized for virulence genes and antibiotic susceptibility. A high incidence of virulence genes was identified in 96.2% of the isolates and 20 different virulence gene profiles were confirmed. DNA amplification showed that 30.8% (16/52) of the S. aureus carried at least one SE gene which causes staphylococcal food poisoning. The most common enterotoxin gene was seg (11.5%) and the egc cluster was detected in 5.8% of the isolates. A combination of hla and hld was the most prevalent coexistence virulence genes and accounted for 59.6% of all isolates. Antibiotic resistance studies showed tetracycline resistance to be the most common at 28.8% while multi-drug resistance was found to be low at 3.8%. In conclusion, the high rate of S. aureus in the sampled sushi and sashimi indicates the need for food safety guidelines. PMID:26861367

  17. Prevalence and antibiotic susceptibility of coagulase-negative Staphylococcus species from bovine subclinical mastitis in dairy herds in the central region of Argentina.

    PubMed

    Raspanti, Claudia G; Bonetto, Cesar C; Vissio, Claudina; Pellegrino, Matías S; Reinoso, Elina B; Dieser, Silvana A; Bogni, Cristina I; Larriestra, Alejandro J; Odierno, Liliana M

    2016-01-01

    Coagulase-negative staphylococci (CNS) are a common cause of bovine subclinical mastitis (SCM). The prevalence of CNS species causing SCM identified by genotyping varies among countries. Overall, the antimicrobial resistance in this group of organisms is increasing worldwide; however, little information exists about a CNS species resistant to antibiotics. The aim of the present study was to genotypically characterize CNS at species level and to determine the prevalence and antibiotic resistance profiles of CNS species isolated from bovine SCM in 51 dairy herds located in the central region of the province of Cordoba, Argentina. In this study, we identified 219 CNS isolates at species level by PCR-restriction fragment length polymorphism of the groEL gene. Staphylococcus chromogenes (46.6%) and Staphylococcus haemolyticus (32%) were the most prevalent species. A minimum of three different CNS species were present in 41.2% of the herds. S. chromogenes was isolated from most of the herds (86.3%), whereas S. haemolyticus was isolated from 66.7% of them. The broth microdilution method was used to test in vitro antimicrobial susceptibility. Resistance to a single compound or two related compounds was expressed in 43.8% of the isolates. S. chromogenes and S. haemolyticus showed a very high proportion of isolates resistant to penicillin. Resistance to two or more non-related antimicrobials was found in 30.6% of all CNS. S. haemolyticus exhibited a higher frequency of resistance to two or more non-related antimicrobials than S. chromogenes. PMID:26935912

  18. Increased susceptibility to beta-lactam antibiotics and decreased porin content caused by envB mutations of Salmonella typhimurium.

    PubMed Central

    Oppezzo, O J; Avanzati, B; Antón, D N

    1991-01-01

    Isogenic derivatives carrying envB6, envB9, or envB+ alleles were obtained from a strain of Salmonella typhimurium that was partially resistant to mecillinam, a beta-lactam antibiotic specific for penicillin-binding protein 2 (PBP 2). Testing of the isogenic strains with several antibacterial agents demonstrated that envB mutations either increased resistance (mecillinam) or did not affect the response (imipemen) to beta-lactams that act primarily on PBP 2, while susceptibilities to beta-lactams that act on PBP 1B, PBP 3, or both were increased. Furthermore, the susceptibilities of envB strains to hydrophobic compounds such as rifampin, novobiocin, or chloramphenicol were not modified, even though their susceptibilities to deoxycholate and crystal violet were enhanced. Outer cell membranes of envB mutants presented a 50% reduction in protein content compared with that of the isogenic envB+ strains, and OmpF and OmpD porins were particularly affected by the reduction. No alteration in the amount or pattern of periplasmic proteins was noticed, and lipopolysaccharides from envB mutants appeared to be normal by sodium dodecyl sulfate-urea-polyacrylamide gel electrophoresis. By using derivatives that produced a plasmid-encoded beta-lactamase, it was demonstrated that envB cells are slightly less permeable to cephalothin than envB+ bacteria are. It is concluded that the high susceptibility of envB mutants to beta-lactams is due to the increased effectiveness of the antibiotics on PBP 1B, PBP 3, or both. Images PMID:1656857

  19. Agar disk elution method for susceptibility testing of Mycobacterium marinum and Mycobacterium fortuitum complex to sulfonamides and antibiotics.

    PubMed Central

    Stone, M S; Wallace, R J; Swenson, J M; Thornsberry, C; Christensen, L A

    1983-01-01

    An agar disk elution method using round well plates, supplemented Mueller-Hinton agar, and commercial drug disks is described for susceptibility testing of Mycobacterium marinum and the rapidly growing mycobacteria to antibiotics and sulfonamides. By this method, 14 of 14 strains of M. marinum were susceptible to rifampin, doxycycline, minocycline, and trimethoprim-sulfamethoxazole. Identical results were obtained with Middlebrook 7H10 agar and drugs prepared from standard powders. With 58 isolates of Mycobacterium fortuitum and Mycobacterium chelonei, this method had a 92% correlation with broth minimal inhibitory concentration determinations for cefoxitin and greater than 98% for doxycycline, kanamycin, amikacin, and the sulfonamides. Sixty-nine percent of isolates of M. chelonei susceptible to amikacin on supplemented Mueller-Hinton agar were resistant on 7H10 agar, and 15 of 16 M. chelonei isolates susceptible to erythromycin in broth were resistant by disk elution when an endpoint of no growth was used with either agar. The agar disk elution method offers a practical method for testing of most antibacterial agents against these mycobacterial species. Images PMID:6651277

  20. Microbiological Surveillance of Peritoneal Dialysis Associated Peritonitis: Antimicrobial Susceptibility Profiles of a Referral Center in GERMANY over 32 Years

    PubMed Central

    Kitterer, Daniel; Latus, Joerg; Pöhlmann, Christoph; Alscher, M. Dominik; Kimmel, Martin

    2015-01-01

    Objectives Peritonitis is one of the most important causes of treatment failure in peritoneal dialysis (PD) patients. This study describes changes in characteristics of causative organisms in PD-related peritonitis and antimicrobial susceptibility. Methods In this single center study we analyzed retrospective 487 susceptibility profiles of the peritoneal fluid cultures of 351 adult patients with peritonitis from 1979 to 2014 (divided into three time periods, P1-P3). Results Staphylococcus aureus decreased from P1 compared to P2 and P3 (P<0.05 and P<0.01, respectively). Methicillin-resistant S. aureus (MRSA) occurred only in P3. Methicillin-resistant Staphylococcus epidermidis (MRSE) increased in P3 over P1 and P2 (P <0.0001, respectively). In P2 and P3, vancomycin resistant enterococci were detected. The percentage of gram-negative organisms remained unchanged. Third generation cephalosporin resistant gram-negative rods (3GCR-GN) were found exclusively in P3. Cefazolin-susceptible gram-positive organisms decreased over the three decades (93% in P1, 75% in P2 and 58% in P3, P<0.01, P<0.05 and P<0.0001, respectively). Vancomycin susceptibility decreased and gentamicin susceptibility in gram-negatives was 94% in P1, 82% in P2 and 90% in P3. Ceftazidim susceptibility was 84% in P2 and 93% in P3. Conclusions Peritonitis caused by MSSA decreased, but peritonitis caused by MRSE increased. MRSA peritonitis is still rare. Peritonitis caused by 3GCR-GN is increasing. An initial antibiotic treatment protocol should be adopted for PD patients to provide continuous surveillance. PMID:26405797

  1. Clinically Relevant Growth Conditions Alter Acinetobacter baumannii Antibiotic Susceptibility and Promote Identification of Novel Antibacterial Agents

    PubMed Central

    Colquhoun, Jennifer M.; Wozniak, Rachel A. F.; Dunman, Paul M.

    2015-01-01

    Biological processes that govern bacterial proliferation and survival in the host-environment(s) are likely to be vastly different from those that are required for viability in nutrient-rich laboratory media. Consequently, growth-based antimicrobial screens performed in conditions modeling aspects of bacterial disease states have the potential to identify new classes of antimicrobials that would be missed by screens performed in conventional laboratory media. Accordingly, we performed screens of the Selleck library of 853 FDA approved drugs for agents that exhibit antimicrobial activity toward the Gram-negative bacterial pathogen Acinetobacter baumannii during growth in human serum, lung surfactant, and/or the organism in the biofilm state and compared those results to that of conventional laboratory medium. Results revealed that a total of 90 compounds representing 73 antibiotics and 17 agents that were developed for alternative therapeutic indications displayed antimicrobial properties toward the test strain in at least one screening condition. Of the active library antibiotics only four agents, rifampin, rifaximin, ciprofloxacin and tetracycline, exhibited antimicrobial activity toward the organism during all screening conditions, whereas the remainder were inactive in ≥ 1 condition; 56 antibiotics were inactive during serum growth, 25 and 38 were inactive toward lung surfactant grown and biofilm-associated cells, respectively, suggesting that subsets of antibiotics may outperform others in differing infection settings. Moreover, 9 antibiotics that are predominantly used for the treatment Gram-positive pathogens and 10 non-antibiotics lacked detectable antimicrobial activity toward A. baumannii grown in conventional medium but were active during ≥ 1 alternative growth condition(s). Such agents may represent promising anti-Acinetobacter agents that would have likely been overlooked by antimicrobial whole cell screening assays performed in traditional

  2. Use of Alignment-Free Phylogenetics for Rapid Genome Sequence-Based Typing of Helicobacter pylori Virulence Markers and Antibiotic Susceptibility

    PubMed Central

    Kusters, Johannes G.

    2015-01-01

    Whole-genome sequencing is becoming a leading technology in the typing and epidemiology of microbial pathogens, but the increase in genomic information necessitates significant investment in bioinformatic resources and expertise, and currently used methodologies struggle with genetically heterogeneous bacteria such as the human gastric pathogen Helicobacter pylori. Here we demonstrate that the alignment-free analysis method feature frequency profiling (FFP) can be used to rapidly construct phylogenetic trees of draft bacterial genome sequences on a standard desktop computer and that coupling with in silico genotyping methods gives useful information for comparative and clinical genomic and molecular epidemiology applications. FFP-based phylogenetic trees of seven gastric Helicobacter species matched those obtained by analysis of 16S rRNA genes and ribosomal proteins, and FFP- and core genome single nucleotide polymorphism-based analysis of 63 H. pylori genomes again showed comparable phylogenetic clustering, consistent with genomotypes assigned by using multilocus sequence typing (MLST). Analysis of 377 H. pylori genomes highlighted the conservation of genomotypes and linkage with phylogeographic characteristics and predicted the presence of an incomplete or nonfunctional cag pathogenicity island in 18/276 genomes. In silico analysis of antibiotic susceptibility markers suggests that most H. pylori hspAmerind and hspEAsia isolates are predicted to carry the T2812C mutation potentially conferring low-level clarithromycin resistance, while levels of metronidazole resistance were similar in all multilocus sequence types. In conclusion, the use of FFP phylogenetic clustering and in silico genotyping allows determination of genome evolution and phylogeographic clustering and can contribute to clinical microbiology by genomotyping for outbreak management and the prediction of pathogenic potential and antibiotic susceptibility. PMID:26135867

  3. Antimicrobial Susceptibility Profiles of Staphylococcus aureus Isolates Recovered from Humans, Environmental Surfaces, and Companion Animals in Households of Children with Community-Onset Methicillin-Resistant S. aureus Infections

    PubMed Central

    Morelli, John J.; Hogan, Patrick G.; Sullivan, Melanie L.; Muenks, Carol E.; Wang, Jeffrey W.; Thompson, Ryley M.; Burnham, Carey-Ann D.

    2015-01-01

    Our objective was to determine the antibiotic susceptibility profiles of Staphylococcus aureus isolates recovered from 110 households of children with community-onset methicillin-resistant S. aureus (MRSA) infections. Cultures were obtained from household members, household objects, and dogs and cats, yielding 1,633 S. aureus isolates. The S. aureus isolates were heterogeneous, although more than half were methicillin resistant. The highest proportion of MRSA was found in bathrooms. The majority of isolates were susceptible to antibiotics prescribed in outpatient settings. PMID:26248385

  4. Mycobacterium arupense flexor tenosynovitis: case report and review of antimicrobial susceptibility profiles for 40 clinical isolates.

    PubMed

    Beam, Elena; Vasoo, Shawn; Simner, Patricia J; Rizzo, Marco; Mason, Erin L; Walker, Randall C; Deml, Sharon M; Brown-Elliott, Barbara A; Wallace, Richard J; Wengenack, Nancy L; Sia, Irene G

    2014-07-01

    We describe a case of chronic tenosynovitis in the hand of a 58-year-old cattle farmer. Surgical biopsy specimens grew Mycobacterium arupense. The patient responded to surgery and antimicrobial therapy based on in vitro susceptibility testing. The antimicrobial susceptibility profiles of the isolate from this patient and 39 additional clinical isolates are presented. PMID:24789193

  5. Microbial profiles at baseline and not the use of antibiotics determine the clinical outcome of the treatment of chronic periodontitis

    PubMed Central

    Bizzarro, S.; Laine, M. L.; Buijs, M. J.; Brandt, B. W.; Crielaard, W.; Loos, B. G.; Zaura, E.

    2016-01-01

    Antibiotics are often used in the treatment of chronic periodontitis, which is a major cause of tooth loss. However, evidence in favour of a microbial indication for the prescription of antibiotics is lacking, which may increase the risk of the possible indiscriminate use of antibiotics, and consequent, microbial resistance. Here, using an open-ended technique, we report the changes in the subgingival microbiome up to one year post-treatment of patients treated with basic periodontal therapy with or without antibiotics. Antibiotics resulted in a greater influence on the microbiome 3 months after therapy, but this difference disappeared at 6 months. Greater microbial diversity, specific taxa and certain microbial co-occurrences at baseline and not the use of antibiotics predicted better clinical treatment outcomes. Our results demonstrate the predictive value of specific subgingival bacterial profiles for the decision to prescribe antibiotics in the treatment of periodontitis, but they also indicate the need for alternative therapies based on ecological approaches. PMID:26830979

  6. Susceptibility of Multidrug-Resistant Gram-Negative Urine Isolates to Oral Antibiotics.

    PubMed

    Hirsch, Elizabeth B; Zucchi, Paola C; Chen, Alice; Raux, Brian R; Kirby, James E; McCoy, Christopher; Eliopoulos, George M

    2016-05-01

    Increasing resistance among Gram-negative uropathogens limits treatment options, and susceptibility data for multidrug-resistant isolates are limited. We assessed the activity of five oral agents against 91 multidrug-resistant Gram-negative urine isolates that were collected from emergency department/hospitalized patients. Fosfomycin and nitrofurantoin were most active (>75% susceptibility). Susceptibilities to sulfamethoxazole-trimethoprim, ciprofloxacin, and ampicillin were ≤40%; empirical use of these agents likely provides inadequate coverage in areas with a high prevalence of multidrug-resistant uropathogens. PMID:26883704

  7. Prevalence, Molecular Characterization, and Antibiotic Susceptibility of Vibrio parahaemolyticus from Ready-to-Eat Foods in China.

    PubMed

    Xie, Tengfei; Xu, Xiaoke; Wu, Qingping; Zhang, Jumei; Cheng, Jianheng

    2016-01-01

    Vibrio parahaemolyticus is the leading cause of foodborne outbreaks, particularly outbreaks associated with consumption of fish and shellfish, and represents a major threat to human health worldwide. This bacterium harbors two main virulence factors: the thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH). Additionally, various serotypes have been identified. The extensive use of antibiotics is a contributing factor to the increasing incidence of antimicrobial-resistant V. parahaemolyticus. In the current study, we aimed to determine the incidence and features of V. parahaemolyticus in ready-to-eat (RTE) foods in China. We found 39 V. parahaemolyticus strains on Chinese RTE foods through investigation of 511 RTE foods samples from 24 cities in China. All isolates were analyzed for the presence of tdh and trh gene by PCR, serotyping was performed using multiplex PCR, antibiotic susceptibility analysis was carried out using the disk diffusion method, and molecular typing was performed using enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR) typing and multilocus sequence typing (MLST). The results showed that none of the isolates were positive for tdh and trh. Most of the isolates (33.3%) were serotype O2. Antimicrobial susceptibility results indicated that most strains were resistant to streptomycin (89.7%), cefazolin (51.3%), and ampicillin (51.3%). The isolates were grouped into five clusters by ERIC-PCR and four clusters by MLST. We updated 10 novel loci and 33 sequence types (STs) in the MLST database. Thus, our findings demonstrated the presence of V. parahaemolyticus in Chinese RTE foods, provided insights into the dissemination of antibiotic-resistant strains, and improved our knowledge of methods of microbiological risk assessment in RTE foods. PMID:27148231

  8. Prevalence, Molecular Characterization, and Antibiotic Susceptibility of Vibrio parahaemolyticus from Ready-to-Eat Foods in China

    PubMed Central

    Xie, Tengfei; Xu, Xiaoke; Wu, Qingping; Zhang, Jumei; Cheng, Jianheng

    2016-01-01

    Vibrio parahaemolyticus is the leading cause of foodborne outbreaks, particularly outbreaks associated with consumption of fish and shellfish, and represents a major threat to human health worldwide. This bacterium harbors two main virulence factors: the thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH). Additionally, various serotypes have been identified. The extensive use of antibiotics is a contributing factor to the increasing incidence of antimicrobial-resistant V. parahaemolyticus. In the current study, we aimed to determine the incidence and features of V. parahaemolyticus in ready-to-eat (RTE) foods in China. We found 39 V. parahaemolyticus strains on Chinese RTE foods through investigation of 511 RTE foods samples from 24 cities in China. All isolates were analyzed for the presence of tdh and trh gene by PCR, serotyping was performed using multiplex PCR, antibiotic susceptibility analysis was carried out using the disk diffusion method, and molecular typing was performed using enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR) typing and multilocus sequence typing (MLST). The results showed that none of the isolates were positive for tdh and trh. Most of the isolates (33.3%) were serotype O2. Antimicrobial susceptibility results indicated that most strains were resistant to streptomycin (89.7%), cefazolin (51.3%), and ampicillin (51.3%). The isolates were grouped into five clusters by ERIC-PCR and four clusters by MLST. We updated 10 novel loci and 33 sequence types (STs) in the MLST database. Thus, our findings demonstrated the presence of V. parahaemolyticus in Chinese RTE foods, provided insights into the dissemination of antibiotic-resistant strains, and improved our knowledge of methods of microbiological risk assessment in RTE foods. PMID:27148231

  9. Differences in the Molecular Epidemiology and Antibiotic Susceptibility of Clostridium difficile Isolates in Pediatric and Adult Patients.

    PubMed

    Kociolek, Larry K; Gerding, Dale N; Osmolski, James R; Patel, Sameer J; Snydman, David R; McDermott, Laura A; Hecht, David W

    2016-08-01

    The rising incidence of Clostridium difficile infections (CDIs) in adults is partly related to the global spread of fluoroquinolone-resistant strains, namely, BI/NAP1/027. Although CDIs are also increasingly diagnosed in children, BI/NAP1/027 is relatively uncommon in children. Little is known about the antibiotic susceptibility of pediatric CDI isolates. C. difficile was cultured from tcdB-positive stools collected from children diagnosed with CDI between December 2012 and December 2013 at an academic children's hospital. CDI isolates were grouped by restriction endonuclease analysis (REA). MICs were measured by agar dilution method for 7 antibiotics. Susceptibility breakpoints were based on guidelines from CLSI and/or the European Committee on Antimicrobial Susceptibility Testing (EUCAST). MICs and REA groupings of C. difficile isolates from 74 adult patients (29 isolates underwent REA) from a temporally and geographically similar adult cohort were compared to those of pediatric isolates. Among 122 pediatric and 74 adult isolates, respectively, the rates of resistance were as follows: metronidazole, 0% and 0%; vancomycin, 0% and 8% (P = 0.003); rifaximin, 1.6% and 6.7% (P = 0.11); clindamycin, 18.9% and 25.3% (P = 0.29); and moxifloxacin, 2.5% and 36% (P = <0.0001). Only 1 of 122 (0.8%) BI/NAP1/027 isolates was identified among the children, compared to 9 of 29 (31%) isolates identified among the adults (P = <0.0001). The 3 moxifloxacin-resistant pediatric isolates were of REA groups BI and CF and a nonspecific group. The 2 rifaximin-resistant pediatric isolates were of REA groups DH and Y. The 21 clindamycin-resistant pediatric isolates were distributed among 9 REA groups (groups A, CF, DH, G, L, M, and Y and 2 unique nonspecific REA groups). These data suggest that a diverse array of relatively antibiotic-susceptible C. difficile strains predominate in a cohort of children with CDI compared to adults. PMID:27270275

  10. Antimicrobial edible apple films inactivate antibiotic resistant and susceptible Campylobacter jejuni strains on chicken breast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Campylobacter jejuni is the leading cause of bacterial diarrheal illness worldwide. Many strains are now becoming multi-drug resistant. To help overcome this problem, apple-based edible films containing carvacrol and cinnamaldehyde were evaluated for their effectiveness against antibiotic resistant...

  11. Prevalence, serotype, virulence characteristics, clonality and antibiotic susceptibility of pathogenic Yersinia enterocolitica from swine feces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Swine are the only known animal reservoir of Yersinia enterocolitica (YE), a human pathogen. Since YE is a fecal organism of swine, the primary goal of this study was to evaluate the prevalence, serotype, virulence plasmid (pYV)-associated characteristics, clonality, and antibiotic su...

  12. Susceptibility of Listeria monocytogenes, L. innocua, and L. welshimeri Isolated from Various Sources to Antibiotics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Listeriosis is a leading cause of death from foodborne illnesses in the United States. Emergence of antimicrobial resistant strains of Listeria monocytogenes could cause major public health concerns. Few studies have examined antimicrobial susceptibility of L. monocytogenes isolated fr...

  13. Identification and antimicrobial susceptibility of enterococci isolated from dogs and cats subjected to differing antibiotic pressures.

    PubMed

    Kataoka, Yasushi; Ito, Chieko; Kawashima, Aya; Ishii, Miki; Yamashiro, Satoko; Harada, Kazuki; Ochi, Hiroki; Sawada, Takuo

    2013-01-01

    The purpose of the present study was to determine the prevalence of antibiotic-resistant enterococci in dogs and cats subjected to differing antibiotic pressures, and the prevalence of vancomycin resistance genes in isolates from these animals. Enterococci were isolated from fecal samples of 65 healthy dogs and 29 healthy cats brought to animal hospitals, from rectal swabs of 73 puppies and 15 kittens from five breeders and two pet shops, and from fecal samples of 20 dogs and 9 cats that were treated with antibiotics in Nippon Veterinary and Life Science University Animal Medical Center. The rates of resistance to ampicillin among isolates from the kitten-puppy group and healthy dog-cat group were 6.8 and 4.3%, respectively. In contrast, the rates of resistance to ampicillin in enterococci from the treatment group under antibiotic pressure were 37.5%. There was a significant difference between the antibiotic-treated group and the untreated group (P<0.01). Similarly, in the treatment group, the rate of resistance to enrofloxacin was extremely high (75.0%). In comparison, in the healthy group and kitten-puppy group, the rates of resistance to enrofloxacin were 23.4 and 12.1%, respectively. Among these groups, a significant difference was also observed in the apparent resistance rates (P<0.01). Vancomycin-resistant enterococci (VRE) harboring vanA or vanB were not detected in any groups. Therefore, contamination of VRE in dogs and cats is still considered to be minimal in Japan. PMID:23358495

  14. Antibiotic Susceptibilities of Enterococcus Species Isolated from Hospital and Domestic Wastewater Effluents in Alice, Eastern Cape Province of South Africa

    PubMed Central

    Iweriebor, Benson Chuks; Gaqavu, Sisipho; Obi, Larry Chikwelu; Nwodo, Uchechukwu U.; Okoh, Anthony I.

    2015-01-01

    Background: Antimicrobial resistance in microorganisms are on the increase worldwide and are responsible for substantial cases of therapeutic failures. Resistance of species of Enterococcus to antibiotics is linked to their ability to acquire and disseminate antimicrobial resistance determinants in nature, and wastewater treatment plants (WWTPs) are considered to be one of the main reservoirs of such antibiotic resistant bacteria. We therefore determined the antimicrobial resistance and virulence profiles of some common Enterococcus spp that are known to be associated with human infections that were recovered from hospital wastewater and final effluent of the receiving wastewater treatment plant in Alice, Eastern Cape. Methods: Wastewater samples were simultaneously collected from two sites (Victoria hospital and final effluents of a municipal WWTP) in Alice at about one to two weeks interval during the months of July and August 2014. Samples were screened for the isolation of enterococci using standard microbiological methods. The isolates were profiled molecularly after targeted generic identification and speciation for the presence of virulence and antibiotic resistance genes. Results: Out of 66 presumptive isolates, 62 were confirmed to belong to the Enterococcus genusof which 30 were identified to be E. faecalis and 15 E. durans. The remaining isolates were not identified by the primers used in the screening procedure. Out of the six virulence genes that were targeted only three of them; ace, efaA, and gelE were detected. There was a very high phenotypic multiple resistance among the isolates and these were confirmed by genetic analyses. Conclusions: Analyses of the results obtained indicated that hospital wastewater may be one of the sources of antibiotic resistant bacteria to the receiving WWTP. Also, findings revealed that the final effluent discharged into the environment was contaminated with multi-resistant enterococci species thus posing a health hazard

  15. Differences in the antimicrobial susceptibility profiles of Moraxella bovis, M. bovoculi and M. ovis

    PubMed Central

    Maboni, Grazieli; Gressler, Leticia T.; Espindola, Julia P.; Schwab, Marcelo; Tasca, Caiane; Potter, Luciana; de Vargas, Agueda Castagna

    2015-01-01

    The aim of this study was to determine the differences in the antimicrobial susceptibility profiles of Moraxella bovis, M. bovoculi and M. ovis. Thirty-two strains of Moraxella spp. isolated from cattle and sheep with infectious keratoconjunctivitis were tested via broth microdilution method to determine their susceptibility to ampicillin, cefoperazone, ceftiofur, cloxacillin, enrofloxacin, florfenicol, gentamicin, neomycin, oxytetracycline and penicillin. The results demonstrated that Moraxella spp. strains could be considered sensitive for most of the antimicrobials tested in this study, but differences between the antimicrobial susceptibility profiles of these three Moraxella species were found. M. bovis might differ from other species due to the higher MIC and MBC values it presented. PMID:26273272

  16. Virulence determinants, antimicrobial susceptibility, and molecular profiles of Erysipelothrix rhusiopathiae strains isolated from China

    PubMed Central

    Ding, Yi; Zhu, Dongmei; Zhang, Jianmin; Yang, Longsheng; Wang, Xiangru; Chen, Huanchun; Tan, Chen

    2015-01-01

    The aim of this study was to understand the epidemiology, serotype, antibiotic sensitivity, and clonal structure of Erysipelothrix rhusiopathiae strains in China. Forty-eight strains were collected from seven provinces during the period from 2012 to 2013. Pulse-field electrophoresis identified 32 different patterns which were classified into clonal groups A–D. Most pulsed-field gel electrophoresis (PFGE) patterns were observed in clonal complex A and B, suggesting high diversity of genetic characterization in these two predominant clonal complexes. Antibiotic sensitivity test shows that all the stains were susceptible to ampicillin, erythromycin, and cefotaxime, and resistant to kanamycin, cefazolin, sulfadiazine, and amikacin. Erythromycin and ampicillin are recommended as first-line antibiotics for treatment of E. rhusiopathiae in China. The high variation in PFGE pattern among the main clonal groups shows that the E. rhusiopathiae in China may originate from different lineages and sources instead of from expansion of a single clonal lineage across different regions. PMID:26975059

  17. Technological characterisation, antibiotic susceptibility and antimicrobial activity of wild-type Leuconostoc strains isolated from North Italian traditional cheeses.

    PubMed

    Morandi, Stefano; Cremonesi, Paola; Silvetti, Tiziana; Brasca, Milena

    2013-11-01

    Genotypic and technological properties, antibiotic susceptibility and antimicrobial activity of 35 Leuconostoc strains, isolated from different Italian raw milk cheeses, were investigated. RAPD-PCR was used to study genetic variability and to distinguish closely related strains. The results showed a high degree of heterogeneity among isolates. All the strains had weak acidifying activity and showed low proteolytic and lipolytic activities. Reduction activity, was generally low. All the Leuconostoc were susceptible to ampicillin, mupirocin, erythromycin, quinupristin/dalfopristin and tetracycline. Many strains were classified as resistant to oxacillin, ciprofloxacin and nitrofurantonin, while all isolates were found resistant to vancomycin. PCR-based detection did not identify any of the common genetic determinants for vancomycin (vanA, vanB, vanC1, vanC2, vanC3, vanD, vanE, vanG) or erythromycin (ermB and ermC). Tetracycline resistance genes were detected in 25 tetracycline susceptible strains, the most frequent one being tetM. One strain, belonging to Ln. pseudomesenteroides species, was positive for the presence of the int gene of the Tn916/Tn1545 trasposon family. This is the first time the conjugative transposon Tn916 has been detected inside the Leuconostoc species. All strains showed antimicrobial activity against Enterococcus faecalis and Ent. faecium. The presence of genes encoding amino-acid decarboxylases (hdc and tdc) was not detected. Some strains are interesting in view of their use in cheese production as starter and non starter cultures. PMID:24067095

  18. Prospective study of catalase-positive coryneform organisms in clinical specimens: identification, clinical relevance, and antibiotic susceptibility.

    PubMed

    Lagrou, K; Verhaegen, J; Janssens, M; Wauters, G; Verbist, L

    1998-01-01

    During a 6-month period, all clinical isolates of catalase-positive coryneform organisms, which were isolated during the routine processing of clinical specimens, were characterized in the laboratory of the 1800-bed University Hospital of Leuven. The distribution of the species in the corynebacteria was: Corynebacterium amycolatum 70 (53%), Corynebacterium jeikeium 16 (12%), Corynebacterium striatum 11 (8%), Corynebacterium afermentans 10 (7%), Corynebacterium minutissimum 9 (6%), CDC coryneform group G 4 (3%), Corynebacterium urealyticum 4 (3%), Corynebacterium glucuronolyticum 1 (0.7%), and Corynebacterium xerosis 1 (0.7%). Of the 150 isolates, 37 (25%) were considered to be infection related and the remaining 113 (75%) were of questionable clinical significance. Susceptibility of the corynebacteria to 12 antibiotics active against Gram-positive organisms was evaluated. C. amycolatum, C. jeikeium, and C. urealyticum were multiresistant, but all isolates were susceptible to teicoplanin and vancomycin. Most of the C. amycolatum strains, and all strains of C. jeikeium and C. striatum, were susceptible to the vibrocidal compound O/129. PMID:9488824

  19. In vitro susceptibility of Pythium insidiosum to macrolides and tetracycline antibiotics.

    PubMed

    Loreto, Erico Silva; Mario, Débora Alves Nunes; Denardi, Laura Bedin; Alves, Sydney Hartz; Santurio, Janio Morais

    2011-07-01

    We describe the in vitro activity of macrolides and tetracycline antibiotics against Pythium insidiosum. The MICs were determined according to CLSI procedures (visual MIC) and by a colorimetric method [3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT)]. The lowest geometric mean (GM) MIC (MICs in μg/ml) (0.39 and 0.7 by visual reading and colorimetric method, respectively) and MIC ranges (0.125 to 2.0) were obtained for minocycline, while the highest MICs were shown for erythromycin (GM of 7.58 and 12.25 by visual reading and colorimetric method, respectively, and MIC ranged from 2 to 32). This significant in vitro activity makes these classes of antibiotics good candidates for experimental treatment of pythiosis. PMID:21537028

  20. In Vitro Susceptibility of Pythium insidiosum to Macrolides and Tetracycline Antibiotics

    PubMed Central

    Loreto, Érico Silva; Mario, Débora Alves Nunes; Denardi, Laura Bedin; Alves, Sydney Hartz; Santurio, Janio Morais

    2011-01-01

    We describe the in vitro activity of macrolides and tetracycline antibiotics against Pythium insidiosum. The MICs were determined according to CLSI procedures (visual MIC) and by a colorimetric method [3-(4,5-dimethyl-2-thiazyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT)]. The lowest geometric mean (GM) MIC (MICs in μg/ml) (0.39 and 0.7 by visual reading and colorimetric method, respectively) and MIC ranges (0.125 to 2.0) were obtained for minocycline, while the highest MICs were shown for erythromycin (GM of 7.58 and 12.25 by visual reading and colorimetric method, respectively, and MIC ranged from 2 to 32). This significant in vitro activity makes these classes of antibiotics good candidates for experimental treatment of pythiosis. PMID:21537028

  1. Direct laser light enhancement of susceptibility of bacteria to gentamicin antibiotic

    NASA Astrophysics Data System (ADS)

    Reznick, Yana; Banin, Ehud; Lipovsky, Anat; Lubart, Rachel; Zalevsky, Zeev

    2011-11-01

    ObjectivesTo test the effect of pulsed (Q-switched) and continuous wave (CW) laser light at wavelength of 532 nm on the viability of free-living stationary phase bacteria with and without gentamicin (an antibiotic) treatment. MethodsFree living stationary phase gram negative bacteria ( Pseudomonas aeruginosa strain PAO1) was immersed in Luria Broth (LB) solution and exposed to Q-switched and CW lasers with and without the addition of the antibiotic gentamicin. Cell viability was determined at different time points. ResultsLaser treatment alone did not reduce cell viability compared to untreated control and the gentamicin treatment alone only resulted in a 0.5 log reduction in the viable count for P. aeruginosa. The combined laser and gentamicin treatment, however, resulted in a synergistic effect and viability was reduced by 8 logs for P. aeruginosa PAO1. ConclusionsCombination of laser light with gentamicin shows an improved efficacy against P. aeruginosa.

  2. Incidence and antibiotic susceptibility of genital mycoplasmas in sexually active individuals in Hungary.

    PubMed

    Pónyai, K; Mihalik, N; Ostorházi, E; Farkas, B; Párducz, L; Marschalkó, M; Kárpáti, S; Rozgonyi, F

    2013-11-01

    The aim of this study was to examine the incidence and antibiotic sensitivity of Ureaplasma urealyticum and Mycoplasma hominis strains cultured from the genital discharges of sexually active individuals who attended our STD outpatient service. Samples were taken with universal swab (Biolab®, Budapest, Hungary) into the Urea-Myco DUO kit (Bio-Rad®, Budapest, Hungary) and incubated in ambient air for 48 h at 37 °C. The determination of antibiotic sensitivity was performed in U9 and arginin broth using the SIR Mycoplasma kit (Bio-Rad®, Budapest, Hungary) under the same conditions. Between 01.05.2008 and 31.12.2011, 373/4,466 (8.35 %) genito-urethral samples with U. urealyticum and 41/4,466 (0.91 %) genito-urethral samples with M. hominis infection were diagnosed in sexually active individuals in the National STD Center, Semmelweis University. U. urealyticum was isolated in 12.54 % in the cervix and 4.1 % in the male urethra, while M. hominis was isolated in 1.33 % in the cervix and 0.51 % in the male urethra. The affected age group was between 21 and 60 years old. U. urealyticum strains were sensitive to tetracycline (95.9 %), doxycycline (97.32 %), and azithromycin (85.79 %), and resistant to erythromycin (81.23 %), clindamycin (75.06 %), and ofloxacin (25.2 %). Cross-resistance occurred in 38.71 % of patients to erythromycin and clindamycin. M. hominis strains were sensitive to clindamycin, ofloxacin, and doxycycline in more than 95 %, to tetracycline in 82.92 %, and no cross-resistance was detected among the antibiotics. Our study confirms that the continuously changing antibiotic resistance of ureaplasmas and mycoplasmas should be followed at least in a few centers in every country, so as to determine the best local therapy options for sexually transmitted infection (STI) patients. PMID:23686458

  3. Digital Quantification of DNA Replication and Chromosome Segregation Enables Determination of Antimicrobial Susceptibility after only 15 Minutes of Antibiotic Exposure.

    PubMed

    Schoepp, Nathan G; Khorosheva, Eugenia M; Schlappi, Travis S; Curtis, Matthew S; Humphries, Romney M; Hindler, Janet A; Ismagilov, Rustem F

    2016-08-01

    Rapid antimicrobial susceptibility testing (AST) would decrease misuse and overuse of antibiotics. The "holy grail" of AST is a phenotype-based test that can be performed within a doctor visit. Such a test requires the ability to determine a pathogen's susceptibility after only a short antibiotic exposure. Herein, digital PCR (dPCR) was employed to test whether measuring DNA replication of the target pathogen through digital single-molecule counting would shorten the required time of antibiotic exposure. Partitioning bacterial chromosomal DNA into many small volumes during dPCR enabled AST results after short exposure times by 1) precise quantification and 2) a measurement of how antibiotics affect the states of macromolecular assembly of bacterial chromosomes. This digital AST (dAST) determined susceptibility of clinical isolates from urinary tract infections (UTIs) after 15 min of exposure for all four antibiotic classes relevant to UTIs. This work lays the foundation to develop a rapid, point-of-care AST and strengthen global antibiotic stewardship. PMID:27357747

  4. Metagenomic profiles of antibiotic resistance genes in paddy soils from South China.

    PubMed

    Xiao, Ke-Qing; Li, Bing; Ma, Liping; Bao, Peng; Zhou, Xue; Zhang, Tong; Zhu, Yong-Guan

    2016-03-01

    Overuse and arbitrary discarding of antibiotics have expanded antibiotic resistance reservoirs, from gut, waste water and activated sludge, to soil, freshwater and even the ocean. Based on the structured Antibiotic Resistance Genes Database and next generation sequencing, metagenomic analysis was used for the first time to detect and quantify antibiotic resistance genes (ARGs) in paddy soils from South China. A total of 16 types of ARGs were identified, corresponding to 110 ARG subtypes. The abundances and distribution pattern of ARGs in paddy soil were distinctively different from those in activated sludge and pristine deep ocean sediment, but close to those of sediment from human-impacted estuaries. Multidrug resistance genes were the most dominant type (38-47.5%) in all samples, and the ARGs detected encompassed the three major resistance mechanisms, among which extrusion by efflux pumps was predominant. Redundancy analysis (RDA) showed that pH was significantly correlated with the distribution of ARG subtypes (P < 0.05). Our results provided a broad spectrum profile of ARGs in paddy soil, indicating that ARGs are widespread in paddy soils of South China. PMID:26850156

  5. Tetracycline-resistant L-forms isolated from an antibiotic-susceptible strain of Listeria monocytogenes.

    PubMed Central

    Schmitt-Slomska, J; Marmouset, M C; Louis, C; Bally, R; Starka, G; Madoff, S

    1982-01-01

    A tetracycline-susceptible strain of Listeria monocytogenes type 4b was converted to stable L-forms by penicillin. L-form variants resistant to tetracycline were then selected from a predominantly tetracycline-susceptible L-form population on plates containing penicillin and increasing concentrations of tetracycline. The origin of tetracycline-resistant L-forms from the parent Listeria strain was confirmed biochemically, by immunofluorescence, and by polyacrylamide gel electrophoresis. Scanning and transmission electron microscopy confirmed the typical L-form structure and the complete lack of cell wall in both L-form strains. The level of [3H]tetracycline uptake was lower in tetracycline-resistant than in susceptible cells. Images PMID:6817706

  6. Characterization and antibiotic susceptibility of Streptococcus agalactiae isolates causing urinary tract infections.

    PubMed

    Piccinelli, Giorgio; Biscaro, Valeria; Gargiulo, Franco; Caruso, Arnaldo; De Francesco, Maria Antonia

    2015-08-01

    Streptococcus agalactiae (GBS) has been implicated in urinary tract infections but the microbiological characteristics and antimicrobial susceptibility of these strains are poorly investigated. In this study, 87 isolates recovered from urine samples of patients who had attended the Spedali Civili of Brescia (Italy) and had single organism GBS cultured were submitted to antimicrobial susceptibility testing, molecular characterization of macrolide and levofloxacin resistance, PCR-based capsular typing and analysis of surface protein genes. By automated broth microdilution method, all isolates were susceptible to penicillin, cefuroxime, cefaclor, and ceftriaxone; 80%, 19.5% and 3.4% of isolates were non-susceptible to tetracycline, erythromycin, and levofloxacin, respectively. Macrolide resistance determinants were iMLS(B) (n=1), cMLS(B) (n=10) and M (n=5), associated with ermTR, ermB and mefA/E. Levofloxacin resistance was linked to mutations in gyrA and parC genes. Predominant capsular types were III, Ia, V, Ib and IX. Type III was associated with tetracycline resistance, while type Ib was associated with levofloxacin resistance. Different capsular type-surface protein gene combinations (serotype V-alp2, 3; serotype III-rib; serotype Ia-epsilon) were detected. A variety of capsular types are involved in significant bacteriuria. The emergence of multidrug resistant GBS may become a significant public health concern and highlights the importance of careful surveillance to prevent the emergence of these virulent GBS. PMID:26144658

  7. Role of porins in the antibiotic susceptibility of Pseudomonas aeruginosa: construction of mutants with deletions in the multiple porin genes.

    PubMed

    Yoneyama, H; Yamano, Y; Nakae, T

    1995-08-01

    We inserted deletions in the chromosomal genes of Pseudomonas aeruginosa coded for the outer membrane porins, proteins C, D2, or E1, and all possible combinations of these proteins by the gene replacement technique and selecting for imipenem-resistance. Determination of the minimum inhibitory concentrations of beta-lactams, fluoroquinolones, chloramphenicol and gentamicin in these mutants revealed that most mutants showed equal susceptibility to the porin-sufficient strain. The only exception was that imipenem and meropenem showed increased minimum inhibitory concentrations in all of the mutants lacking protein D2. These results firmly established that the P. aeruginosa porins identified so far form the pores do not accommodate the passage of most antipseudomonal antibiotics, with the exception of carbapenems. PMID:7639767

  8. Prevalence, virulence and antibiotic susceptibility of Salmonella spp. strains, isolated from beef in Greater Tunis (Tunisia).

    PubMed

    Oueslati, Walid; Rjeibi, Mohamed Ridha; Mhadhbi, Moez; Jbeli, Mounir; Zrelli, Samia; Ettriqui, Abdelfettah

    2016-09-01

    The aim of this work was to investigate the presence of Salmonella spp. in 300 beef meat samples collected from cattle carcasses of different categories (young bulls, culled heifers and culled cows). The detection of Salmonella spp. was performed by the alternative VIDAS Easy Salmonella technique and confirmed by PCR using Salmonella specific primers. Salmonella serotypes were determined by slide agglutination tests. The resistance to 12 antibiotics was determined by the diffusion method on Mueller-Hinton agar antibiotic discs. The overall contamination rate of beef by Salmonella spp. was 5.7% (17/300). This rate varied from naught (0/100) in bulls' meat to 14% (14/100) in culled cows' meat (p<0.001). The prevalence of Salmonella spp. was higher in summer and in cattle with digestive disorders: chronic gastroenteritis (6/17), traumatic peritonitis (3/17) and intestinal obstruction (2/17) (p<0.0001). Of the 17 Salmonella isolates, 6 serotypes were identified, namely Salmonella Montevideo (8/17), Salmonella Anatum (3/17), Salmonella Minnesota (2/17), Salmonella Amsterdam (2/17), Salmonella Kentucky (1/17) and Salmonella Brandenburg (1/17) (p<0.05). Unlike other serotypes, S. Montevideo was present during the whole year except winter. Almost all of the strains (16/17) were resistant to at least one of the 12 tested antibiotics. Multidrug-resistance concerned 14/17 of the strains, including Amoxicillin (13/17), Tetracycline (12/17), Streptomycin (10/17) and Nalidixic acid (6/17). All the strains were sensitive to the association (Amoxicillin+Clavulanic acid), Cefoxitin and Ceftazidime. In addition, our study showed that all Salmonella strains (17) were positive for invasion gene invA and negative for the virulence gene spvC. Only one isolate (S. Kentucky) harbored the h-li virulence gene. PMID:27183540

  9. Identification and Determination of Antibiotic Susceptibilities of Brucella Strains Isolated from Patients in Van, Turkey by Conventional and Molecular Methods

    PubMed Central

    Parlak, Mehmet; Güdücüoğlu, Hüseyin; Bayram, Yasemin; Çıkman, Aytekin; Aypak, Cenk; Kılıç, Selçuk; Berktaş, Mustafa

    2013-01-01

    Purpose: Brucellosis is a worldwide zoonotic disease and still constitutes a major public health problem. In this study, we aimed to identify biovars of Brucella strains isolated from clinical specimens taken from brucellosis patients from the Eastern Anatolia region as well determine the susceptibility of these isolates to tigecycline and azithromycin, drugs that may serve as alternatives to the conventional drugs used in the therapy. Materials and methods: Seventy-five Brucella spp. isolates were included in the study. All strains were identified by both conventional and molecular methods. Brucella Multiplex PCR kit (FC-Biotech, Code: 0301, Turkey) and B. melitensis biovar typing PCR kit (FC-Biotech, Code: 0302, Turkey) were used for molecular typing. Antimicrobial susceptibilities of all strains were determined by E-tests. Results: By conventional biotyping, 73 strains were identified as B. melitensis biovar 3 and two strains as B. abortus biovar 3. Molecular typing results were compatible with conventional methods. The MIC50 and MIC90 values of doxycycline were 0.047 and 0.094; tigecycline 0.094 and 0.125; trimethoprim/sulfamethoxazole 0.064 and 0.19; ciprofloxacin 0.19 for both; streptomycin 0.75 and 1; rifampin 1 and 2 and azithromycin 4 and 8. According to the MIC values, doxycycline was found to be the most effective antibiotic, followed by tigecycline, trimethoprim-sulfamethoxazole and ciprofloxacin. Conclusion: Currently recommended antibiotics for the treatment of brucellosis such as doxycycline, rifampin, streptomycin, trimethoprim-sulfamethoxazole and ciprofloxacin were found to be still effective. While our results showed that tigecycline can be used an alternative agent in the treatment of brucellosis, azithromycin has not been confirmed as an appropriate agent for the treatment. PMID:23983603

  10. Multicenter Study of Antibiotic Resistance Profile of H. pylori and Distribution of CYP2C19 Gene Polymorphism in Rural Population of Chongqing, China

    PubMed Central

    Han, Ran; Lu, Hong; Jiang, Ming-Wan; Tan, Ke-Wen; Peng, Zhong; Hu, Jia-Li; Fang, Dian-Chun; Lan, Chun-Hui; Wu, Xiao-Ling

    2016-01-01

    This study was to investigate the antibiotic resistance profile of H. pylori and the distribution of CYP2C19 gene polymorphism in rural population of Chongqing, China. 214 and 111 strains of H. pylori were isolated from rural and urban patients, respectively. 99.53%, 20.09%, and 23.36% of the isolates in rural patients were found to be resistant to metronidazole, clarithromycin, and levofloxacin, while the resistant rate in urban patients was 82.88%, 19.82%, and 24.32%. The multiple antibiotic resistance percentage significantly increased from 28.26% (below 45 years) to 41.80% (above 45 years) in rural patients. Up to 44.39%, 45.79%, and 9.81% of rural patients from whom H. pylori was isolated were found to be extensive metabolizers, intermediate metabolizers, and poor metabolizers. No correlation was observed between antibiotic resistance profile of H. pylori and genetic polymorphism of CYP2C19 among rural population. There was a high prevalence of H. pylori strains resistant to metronidazole, clarithromycin, and levofloxacin in rural patients in Chongqing, China. The choice of therapy in this area should be based on local susceptibility patterns. Amoxicillin, gentamicin, and furazolidone are recommended as the first-line empiric regimen. PMID:27247569

  11. Antibiotic susceptibility patterns and prevalence of group B Streptococcus isolated from pregnant women in Misiones, Argentina

    PubMed Central

    Quiroga, M.; Pegels, E.; Oviedo, P.; Pereyra, E.; Vergara, M.

    2008-01-01

    This study was performed to determine the susceptibility patterns and the colonization rate of Group B Streptococcus (GBS) in a population of pregnant women. From January 2004 to December 2006, vaginal-rectal swabs were obtained from 1105 women attending Dr. Ramón Madariaga Hospital, in Posadas, Misiones, Argentina. The carriage rate of GBS among pregnant women was 7.6%. A total of 62 GBS strains were randomly selected for in vitro susceptibility testing to penicillin G, ampicillin, tetracycline, levofloxacin, gatifloxacin, ciprofloxacin, quinupristin-dalfopristin, linezolid, vancomycin, rifampicin, trimethoprim- sulfametoxazol, nitrofurantoin, gentamicin, clindamycin and erythromycin, and determination of resistance phenotypes. No resistance to penicillin, ampicillin, quinupristin-dalfopristin, linezolid, and vancomycin was found. Of the isolates examined 96.8%, 98.3%, 46.8%, and 29.0% were susceptible to rifampicin, nitrofurantoin, trimethoprim-sulfametoxazol and tetracycline, respectively. Rank order of susceptibility for the quinolones was: gatifloxacin (98.4%) > levofloxacin (93.5%) > ciprofloxacin (64.5%). The rate of resistance to erythromycin (9.7%) was higher than that of other reports from Argentina. High-level resistance to gentamicin was not detected in any of the isolates. Based on our finding of 50% of GBS isolates with MIC to gentamicin equal o lower than 8 μg/ml, a concentration used in one of the selective media recommended for GBS isolation, we suggested, at least in our population, the use of nalidixic acid and colistin in selective media with the aim to improve the sensitivity of screening cultures for GBS carriage in women. PMID:24031210

  12. Case of Mycobacterium marinum infection with unusual patterns of susceptibility to commonly used antibiotics.

    PubMed

    Parrish, Nicole; Luethke, Ronald; Dionne, Kim; Carroll, Karen; Riedel, Stefan

    2011-05-01

    Mycobacterium marinum, found commonly in salt water and freshwater, is the causative agent of disease in many species of fish and occasionally in humans. MICs to most antimicrobial agents are relatively low. Susceptibility testing is not routinely performed, and single-drug therapy is used for the treatment of most infections. Here, we report an infection caused by a drug-resistant M. marinum strain in an otherwise healthy patient. PMID:21430095

  13. [Investigation of the serotype distribution, biofilm production and antibiotic susceptibilities of group B streptococci isolated from urinary samples].

    PubMed

    Baba, Sevinç; Aydın, Mustafa Derya

    2016-07-01

    Streptococcus agalactiae (Group B streptococcus, GBS), a member of normal flora of human gastrointestinal and genitourinary systems, is a leading cause of sepsis, meningitis, and pneumonia particularly in newborn. GBS can also cause severe infections in pregnant women and adults with underlying disease, as well as mild diseases, such as urinary tract infections (UTIs). GBS strains exhibit 10 different serotypes, and the identification of serotype distribution is important epidemiologically. The role of biofilm production is one of the virulence factors that has been discussed in the pathogenesis of GBS infections. Although resistance to penicillin and ampicillin has not been documented in GBS, different rates of resistance has been reported for the alternative antibiotics to penicillin. The aim of this study was to investigate the serotype distribution, the ability of biofilm formation and the antibiotic susceptibilities of S.agalactiae strains isolated from urine cultures. A total of 60 strains were included in the study, 40 of them were isolated from patients (38 female 2 male; mean age: 36.7 years) with urinary tract complaints whose cultures yielded single type of colonies in the number of ≥ 50.000 cfu/ml, whereas 20 of them were isolated from patients (19 female 1 male; mean age: 37.2 years) without urinary tract complaints whose cultures yielded mixed colonies in the number of ≤ 20.000 cfu/ml. Chromogenic media were used for the isolation and the isolates were identified by conventional methods. The isolates were then serotyped by latex agglutination method and their antibiotic susceptibilities were determined by disk diffusion method recommended by CLSI documents. Biofilm formation of the strains were investigated by microplate and Congo red agar (CRA) methods. In our study, the most frequently detected serotypes were V (n= 18; 30%) and II (n= 14; 23.3%), followed by serotype Ia (n= 10; 16.7%), III (n= 9; 15%), Ib (n= 3; 5%), VI (n= 1; 1.7%) and VII (n

  14. Etiology and antibiotic susceptibility of bacterial pathogens responsible for community-acquired urinary tract infections in Poland.

    PubMed

    Stefaniuk, E; Suchocka, U; Bosacka, K; Hryniewicz, W

    2016-08-01

    Urinary tract infections (UTIs) are some of the most common infections in both community and hospital settings infections. With their high rate of incidence, recurrence, complications, diverse etiologic agents, as well as growing antibiotic resistance, UTIs have proven to be a serious challenge for medical professionals. The aim of this study was to obtain data on the susceptibility patterns of pathogens responsible for UTIs in Poland to currently used antibiotics. A total of 396 bacterial isolates were collected between March and May 2013 from 41 centers in all regions of Poland. The majority of isolates were from adult patients (96.2 %); 144 (37.8 %) patients were diagnosed with uncomplicated UTI, while the remaining 237 (62.2 %) had a complicated infection. The most prevalent pathogen was Escherichia coli (71.4 %), followed by Klebsiella spp. (10.8 %) and the Proteae group (7.6 %). Escherichia coli was responsible for 80.6 % of cases of uncomplicated and 65.8 % of complicated infections. Only 65.8 % of E. coli isolates were susceptible to ciprofloxacin (uncomplicated 75.9 %, complicated 58.3 %), 64.0 % to nitrofurantoin (67.2 %, 62.8 %), 65.1 % to trimethoprim/sulfamethoxazole (68.1 %, 62.8 %), and 66.4 % to fosfomycin (77.6 %, 62.2 %). Among E. coli isolates from all UTIs, only 43.4 % were susceptible to ampicillin, with 47.4 % from uncomplicated compared with 40.4 % from complicated infections; 88.2 % to amoxicillin/clavulanic acid (91.4 % vs. 85.9 % complicated); 90.1 % to cefuroxime (93.1 %, 87.8 %); and 94.1 % to cefotaxime (98.2 %, 91.0 %). Thirty-five strains (10.4 %) were capable of producing extended-spectrum β-lactamases (ESBLs). This study demonstrates an increase in multidrug-resistant strains, especially among the leading pathogens associated with UTIs, including E. coli, Klebsiella spp., and Proteus spp. PMID:27189078

  15. [Distribution of emm genotypes and antibiotic susceptibility of Streptococcus pyogenes strains: analogy with the vaccine in development].

    PubMed

    Arslan, Uğur; Oryaşın, Erman; Eskin, Zeynep; Türk Dağı, Hatice; Fındık, Duygu; Tuncer, Inci; Bozdoğan, Bülent

    2013-04-01

    Streptococcus pyogenes is the most common bacterial pathogen causing pharyngotonsillitis, and also can lead to diseases such as otitis media, impetigo, necrotizing fasciitis, bacteremia, sepsis and toxic shock-like syndrome. M protein encoded by emm gene is an important virulence factor of S.pyogenes and it is used for genotyping in epidemiological studies. The aims of this study were to determine the M protein types of group A streptococci (GAS) by using emm gene sequence analysis method, to compare the M types in terms of analogy with the vaccine in development and to determine the antibiotic susceptibilities of the isolates. A total of 35 GAS strains isolated from various clinical specimens in our laboratory were included in the study. Strains growing in blood culture were considered as invasive, strains growing in throat and abscess cultures were considered as non-invasive. The isolates have been identified by conventional methods and 16S rRNA sequence analysis at species level. emm genotyping of strains identified as S.pyogenes, was performed by PCR method as proposed by the CDC. Amplicons were obtained and sequenced in 23 out of 35 isolates. The results were compared with CDC emm sequence database. Antibiotic susceptibility of the isolates was performed by agar dilution method and evaluated as recommended by CLSI. Twenty-three out of 35 isolates could be typed and 15 different emm genotypes were detected. The most common emm types were emm1 (22%), emm89 (13%), emm18 (9%) and emm19 (9%). The detection rate of other emm types (emm5, 12, 14, 17, 26, 29, 37, 74, 78, 92, 99) was 47%. Types emm1, 12, 19, 74, 89 and 99 were observed in strains isolated from blood cultures. It was detected that nine of the 15 (60%) emm types are within the contents of 26 valent vaccine (emm 1, 5, 12, 14, 18, 19, 29, 89, 92). It was also observed that 17 (74%) of the 23 cases were infected by vaccine types and the four emm types (emm1, 12, 19, 89) identified in blood samples were

  16. In vitro antibiotic susceptibility of Dutch Mycoplasma synoviae field isolates originating from joint lesions and the respiratory tract of commercial poultry.

    PubMed

    Landman, W J M; Mevius, D J; Veldman, K T; Feberwee, A

    2008-08-01

    The in vitro susceptibility of 17 Dutch Mycoplasma synoviae isolates from commercial poultry to enrofloxacin, difloxacin, doxycycline, tylosin and tilmicosin was examined. Three isolates originated from joint lesions and 14 were from the respiratory tract. The type strain M. synoviae WVU 1853 was included as a control strain. Antibiotic susceptibility was tested quantitatively using the broth microdilution test. Based on initial and final minimum inhibitory concentration values, all tested isolates were susceptible to doxycycline, tylosin and tilmicosin. Two isolates from the respiratory tract were resistant to enrofloxacin and showed intermediate resistance to difloxacin. PMID:18622859

  17. Antimicrobial susceptibility profiles of Helicobacter pylori isolated from patients in North India.

    PubMed

    Gehlot, Valentina; Mahant, Shweta; Mukhopadhyay, Asish Kumar; Das, Kunal; De, Ronita; Kar, Premashis; Das, Rajashree

    2016-06-01

    Helicobacter pylori-related gastroduodenal diseases are very common in India. Antibiotic resistance to commonly used antibiotics against H. pylori is increasing very rapidly. The aim of this study was to determine the antimicrobial susceptibility patterns of H. pylori strains from India against commonly used antibiotics in H. pylori treatment. Helicobacter pylori were cultured from 68 patients suffering from various gastroduodenal diseases in North India. Minimum inhibitory concentrations (MICs) to different antibiotics were determined by agar dilution. The clinical diagnosis of the 68 patients who were H. pylori culture-positive were gastro-oesophageal reflux disease (GERD) (n=23), non-erosive reflux disease (NERD) (n=22), non-ulcer dyspepsia (NUD) (n=13), antral gastritis (n=3), duodenal ulcer (n=2) and others (n=5). Of the 68 H. pylori isolates, 20 (29.4%) showed no resistance. The prevalence of drug resistance was 70.6%, including resistance to metronidazole (48.5%), furazolidone (22.1%), amoxicillin (17.6%), tetracycline (16.2%) and clarithromycin (11.8%). Dual and multiple drug resistance were found in 26.5% and 8.8% of cases, respectively. In conclusion, more than two-thirds of the isolated H. pylori strains showed resistance to at least one of the antibiotics for H. pylori treatment. Metronidazole resistance was most prevalent amongst the isolates tested. Emergence of dual and multidrug resistance is of great concern and there is an urgent need for regular antibiotic resistance surveillance studies. Amoxicillin- and clarithromycin-based anti-H. pylori regimens commonly prescribed for triple therapy in India show least resistance and hence are appropriate for anti-H. pylori management in India. PMID:27436467

  18. COMPARISON BETWEEN AUTOMATED SYSTEM AND PCR-BASED METHOD FOR IDENTIFICATION AND ANTIMICROBIAL SUSCEPTIBILITY PROFILE OF CLINICAL Enterococcus spp

    PubMed Central

    Furlaneto-Maia, Luciana; Rocha, Kátia Real; Siqueira, Vera Lúcia Dias; Furlaneto, Márcia Cristina

    2014-01-01

    Enterococci are increasingly responsible for nosocomial infections worldwide. This study was undertaken to compare the identification and susceptibility profile using an automated MicrosScan system, PCR-based assay and disk diffusion assay of Enterococcus spp. We evaluated 30 clinical isolates of Enterococcus spp. Isolates were identified by MicrosScan system and PCR-based assay. The detection of antibiotic resistance genes (vancomycin, gentamicin, tetracycline and erythromycin) was also determined by PCR. Antimicrobial susceptibilities to vancomycin (30 µg), gentamicin (120 µg), tetracycline (30 µg) and erythromycin (15 µg) were tested by the automated system and disk diffusion method, and were interpreted according to the criteria recommended in CLSI guidelines. Concerning Enterococcus identification the general agreement between data obtained by the PCR method and by the automatic system was 90.0% (27/30). For all isolates of E. faecium and E. faecalis we observed 100% agreement. Resistance frequencies were higher in E. faecium than E. faecalis. The resistance rates obtained were higher for erythromycin (86.7%), vancomycin (80.0%), tetracycline (43.35) and gentamicin (33.3%). The correlation between disk diffusion and automation revealed an agreement for the majority of the antibiotics with category agreement rates of > 80%. The PCR-based assay, the van(A) gene was detected in 100% of vancomycin resistant enterococci. This assay is simple to conduct and reliable in the identification of clinically relevant enterococci. The data obtained reinforced the need for an improvement of the automated system to identify some enterococci. PMID:24626409

  19. Bacterial contamination, bacterial profile and antimicrobial susceptibility pattern of isolates from stethoscopes at Jimma University Specialized Hospital

    PubMed Central

    2013-01-01

    Introduction Hospital acquired infections are recognized as critical public health problems. Infections are frequently caused by organisms residing in healthcare environment, including contaminated medical equipment like Stethoscopes. Objective To determine bacterial contamination, bacterial profile and anti-microbial susceptibility pattern of the isolates from stethoscopes at Jimma University Specialized Hospital. Methodology Cross-sectional study conducted from May to September 2011 at Jimma University Specialized Hospital. One hundred seventy-six stethoscopes owned by Health Care Workers (HCWs) and Medical students were randomly selected and studied. Self-administered structured questionnaire was used to collect socio-demographic data. Specimen was collected using moisten sterile cotton swab and 1 ml normal saline was used to transport the specimen, all laboratory investigations were done following standard microbiological techniques, at Microbiology Laboratory, Jimma University. SPSS windows version 16 used for data analysis and P <0.05 was considered statistically significant. Result: A total, of 151 (85.8%) stethoscopes were contaminated. A total of 256 bacterial strains and a mean of 1.44×104 CFUs/diaphragm of stethoscopes was isolated. Of the 256 isolates, 133 (52%) were potential pathogens like S. aureus, Klebsiella spp., Citrobacter spp., Salmonella spp., Proteus spp., Enterobacter spp., P. aeruginosa and E. coli. All strains were resistant to multiple classes of antibiotics (two to eight classes of antibiotics). Disinfection practice was poor. Disinfection practice was found to be associated with bacterial contamination of stethoscopes (P < 0.05). High contamination rate 100 (90.9%) was observed among stethoscopes that had never been disinfected; while the least contamination 29 (72.2%) was found on those disinfected a week or less before the survey. Conclusion Bacterial contamination of the stethoscope was significant. The isolates were potential

  20. Resistance profile for pathogens causing urinary tract infection in a pediatric population, and antibiotic treatment response at a University Hospital, 2010-2011

    PubMed Central

    Vélez Echeverri, Catalina; Serrano, Ana Katherina; Ochoa-García, Carolina; Rojas Rosas, Luisa; María Bedoya, Ana; Suárez, Margarita; Hincapié, Catalina; Henao, Adriana; Ortiz, Diana; Vanegas, Juan José; Zuleta, John Jairo; Espinal, David

    2014-01-01

    Introduction: Urinary tract infection (UTI) is one of the most common bacterial infections in childhood and causes acute and chronic morbidity and long-term hypertension and chronic kidney disease. Objectives: To describe the demographic characteristics, infectious agents, patterns of antibiotic resistance, etiologic agent and profile of susceptibility and response to empirical treatment of UTI in a pediatric population. Methods: This is a descriptive, retrospective study. Results: Included in the study were 144 patients, 1:2.06 male to female ratio. The most common symptom was fever (79.9%) and 31.3% had a history of previous UTI. 72.0% of the patients had positive urine leukocyte count (>5 per field), urine gram was positive in 85.0% of samples and gram negative bacilli accounted for 77.8% for the total pathogens isolated. The most frequent uropathogens isolated were Escherichia coli and Klebsiella pneumoniae. Our E.coli isolates had a susceptibility rate higher than 90% to most of the antibiotics used, but a resistance rate of 42.6% to TMP SMX and 45.5% to ampicillin sulbactam. 6.3% of E. coli was extended-spectrum beta-lactamases producer strains. The most frequent empirical antibiotic used was amikacin, which was used in 66.0% of the patients. 17 of 90 patients who underwent voiding cistouretrography (VCUG) had vesicoureteral reflux. Conclusion: This study revealed that E. coli was the most frequent pathogen of community acquired UTI. We found that E. coli and other uropathogens had a high resistance rate against TMP SMX and ampicillin sulbactam. In order to ensure a successful empirical treatment, protocols should be based on local epidemiology and susceptibility rates. PMID:24970958

  1. Coagulase-negative staphylococci from non-mastitic bovine mammary gland: characterization of Staphylococcus chromogenes and Staphylococcus haemolyticus by antibiotic susceptibility testing and pulsed-field gel electrophoresis.

    PubMed

    Pate, Mateja; Zdovc, Irena; Avberšek, Jana; Ocepek, Matjaž; Pengov, Andrej; Podpečan, Ožbalt

    2012-05-01

    During routine microbiological examination of milk samples from dairy cows without clinical signs of mastitis, quarter milk samples of 231 dairy cows from 12 herds were investigated for the presence of coagulase-negative staphylococci (CNS). The isolates were identified on the basis of colony morphology, Gram staining, catalase and coagulase test and the commercial kit, API Staph. CNS was detected in 29% (67/231) of the cows. A total of seven CNS species were identified with the most prevalent being Staphylococcus (Staph.) chromogenes (30%) and Staph. haemolyticus (28·8%), followed by Staph. simulans (11·2%), Staph. xylosus (11·2%), Staph. epidermidis (7·5%), Staph. hyicus (6·3%) and Staph. sciuri (5%). The predominant species, Staph. chromogenes and Staph. haemolyticus, were further characterized by antibiotic susceptibility testing using the agar disc diffusion method (Kirby-Bauer) and by pulsed-field gel electrophoresis (PFGE). Considerable resistance to ampicillin and penicillin was observed in both species. Isolates with identical or highly similar PFGE profiles were detected at the herd level despite a marked heterogeneity seen for both species. On the basis of somatic cell count, absence of clinical signs of inflammation and heterogeneity of genotypes, we assume that CNS isolated in this study could not be considered as important causative agents of the bovine mammary gland inflammation. PMID:22067091

  2. Differences between macrolide-resistant and -susceptible Streptococcus pyogenes: importance of clonal properties in addition to antibiotic consumption.

    PubMed

    Silva-Costa, C; Friães, A; Ramirez, M; Melo-Cristino, J

    2012-11-01

    A steady decline in macrolide resistance among Streptococcus pyogenes (group A streptococci [GAS]) in Portugal was reported during 1999 to 2006. This was accompanied by alterations in the prevalence of macrolide resistance phenotypes and in the clonal composition of the population. In order to test whether changes in the macrolide-resistant population reflected the same changing patterns of the overall population, we characterized both macrolide-susceptible and -resistant GAS associated with a diagnosis of tonsillo-pharyngitis recovered in the period from 2000 to 2005 in Portugal. Pulsed-field gel electrophoresis (PFGE) profiling was the best predictor of emm type and the only typing method that could discriminate clones associated with macrolide resistance and susceptibility within each emm type. Six PFGE clusters were significantly associated with macrolide susceptibility: T3-emm3-ST406, T4-emm4-ST39, T1-emm1-ST28, T6-emm6-ST382, B3264-emm89-ST101/ST408, and T2-emm2-ST55. Four PFGE clusters were associated with macrolide resistance: T4-emm4-ST39, T28-emm28-ST52, T12-emm22-ST46, and T1-emm1-ST28. We found no evidence for frequent ongoing horizontal transfer of macrolide resistance determinants. The diversity of the macrolide-resistant population was lower than that of susceptible isolates. The differences found between the two populations suggest that the macrolide-resistant population of GAS has its own dynamics, independent of the behavior of the susceptible population. PMID:22908153

  3. Effects of scopolamine on autonomic profiles underlying motion sickness susceptibility

    NASA Technical Reports Server (NTRS)

    Uijtdehaage, Sebastian H. J.; Stern, Robert M.; Koch, Kenneth L.

    1993-01-01

    The purpose of this study was to examine the effects of scopolamine on the physiological patterns occurring prior to and during motion sickness stimulation. In addition, the use of physiological profiles in the prediction of motion sickness was evaluated. Sixty subjects ingested either 0.6 mg scopolamine, 2.5 mg methoscopolamine, or a placebo. Heart rate (HR), respiratory sinus arrhythmia (an index of vagal tone), and electrogastrograms were measured prior to and during the exposure to a rotating optokinetic drum. Compared to the other groups, the scopolamine group reported fewer motion sickness symptoms, and displayed lower HR, higher vagal tone, enhanced normal gastric myoelectric activity, and depressed gastric dysrhythmias before and during motion sickness induction. Distinct physiological profiles prior to drum rotation could reliably differentiate individuals who would develop gastric discomfort from those who would not. Symptom-free subjects were characterized by high levels of vagal tone and low HR across conditions, and by maintaining normal (3 cpm) electrogastrographic activity during drum rotation. It was concluded that scopolamine offered motion sickness protection by initiating a pattern of increased vagal tone and gastric myoelectric stability.

  4. Metagenomic Profiling of Microbial Composition and Antibiotic Resistance Determinants in Puget Sound

    PubMed Central

    Port, Jesse A.; Wallace, James C.; Griffith, William C.; Faustman, Elaine M.

    2012-01-01

    Human-health relevant impacts on marine ecosystems are increasing on both spatial and temporal scales. Traditional indicators for environmental health monitoring and microbial risk assessment have relied primarily on single species analyses and have provided only limited spatial and temporal information. More high-throughput, broad-scale approaches to evaluate these impacts are therefore needed to provide a platform for informing public health. This study uses shotgun metagenomics to survey the taxonomic composition and antibiotic resistance determinant content of surface water bacterial communities in the Puget Sound estuary. Metagenomic DNA was collected at six sites in Puget Sound in addition to one wastewater treatment plant (WWTP) that discharges into the Sound and pyrosequenced. A total of ∼550 Mbp (1.4 million reads) were obtained, 22 Mbp of which could be assembled into contigs. While the taxonomic and resistance determinant profiles across the open Sound samples were similar, unique signatures were identified when comparing these profiles across the open Sound, a nearshore marina and WWTP effluent. The open Sound was dominated by α-Proteobacteria (in particular Rhodobacterales sp.), γ-Proteobacteria and Bacteroidetes while the marina and effluent had increased abundances of Actinobacteria, β-Proteobacteria and Firmicutes. There was a significant increase in the antibiotic resistance gene signal from the open Sound to marina to WWTP effluent, suggestive of a potential link to human impacts. Mobile genetic elements associated with environmental and pathogenic bacteria were also differentially abundant across the samples. This study is the first comparative metagenomic survey of Puget Sound and provides baseline data for further assessments of community composition and antibiotic resistance determinants in the environment using next generation sequencing technologies. In addition, these genomic signals of potential human impact can be used to guide

  5. Detecting bacteria and Determining Their Susceptibility to Antibiotics by Stochastic Confinement in Nanoliter Droplets using Plug-Based Microfluidics

    SciTech Connect

    Boedicker, J.; Li, L; Kline, T; Ismagilov, R

    2008-01-01

    This article describes plug-based microfluidic technology that enables rapid detection and drug susceptibility screening of bacteria in samples, including complex biological matrices, without pre-incubation. Unlike conventional bacterial culture and detection methods, which rely on incubation of a sample to increase the concentration of bacteria to detectable levels, this method confines individual bacteria into droplets nanoliters in volume. When single cells are confined into plugs of small volume such that the loading is less than one bacterium per plug, the detection time is proportional to plug volume. Confinement increases cell density and allows released molecules to accumulate around the cell, eliminating the pre-incubation step and reducing the time required to detect the bacteria. We refer to this approach as stochastic confinement. Using the microfluidic hybrid method, this technology was used to determine the antibiogram - or chart of antibiotic sensitivity - of methicillin-resistant Staphylococcus aureus (MRSA) to many antibiotics in a single experiment and to measure the minimal inhibitory concentration (MIC) of the drug cefoxitin (CFX) against this strain. In addition, this technology was used to distinguish between sensitive and resistant strains of S. aureus in samples of human blood plasma. High-throughput microfluidic techniques combined with single-cell measurements also enable multiple tests to be performed simultaneously on a single sample containing bacteria. This technology may provide a method of rapid and effective patient-specific treatment of bacterial infections and could be extended to a variety of applications that require multiple functional tests of bacterial samples on reduced timescales.

  6. Antimicrobial susceptibility profiling and genomic diversity of Acinetobacter baumannii isolates: A study in western Iran

    PubMed Central

    Mohajeri, Parviz; Farahani, Abbas; Feizabadi, Mohammad Mehdi; Ketabi, Hosnieh; Abiri, Ramin; Najafi, Farid

    2013-01-01

    Background and Objective Acinetobacter baumannii is an aerobic non-motile Gram-negative bacterial pathogen that is resistant to most antibiotics. Carbapenems are the most common antibiotics for the treatment of infections caused by this pathogen. Mechanisms of antibiotic-resistance in A. baumannii are mainly mediated by efflux pumps-lactamases. The aim of this study was to determine antibiotic susceptibility, the possibility of existence of OXAs genes and fingerprinting by Pulsed-Field Gel Electrophoresis (PFGE) among clinical isolates of Acinetobacter collected from Kermanshah hospitals. Materials and Methods One hundred and four isolates were collected from patients attending Imam Reza, Taleghani and Imam Khomeini hospitals of Kermanshah (Iran). Isolates were identified by biochemical tests and API 20NE kit. The susceptibility to different antibiotics was assessed with Kirby-Bauer disk diffusion method. PCR was performed for detection of bla OXA-23, bla OXA-24, bla OXA-51 and bla OXA-58 beta-lactamase genes. Clonal relatedness was estimated by PFGE (with the restriction enzyme Apa I) and DNA patterns were analyzed by Gel compare II 6.5 software. Results All isolates showed high-level of resistance to imipenem, meropenem as well as to other antimicrobial agents, while no resistance to polymyxin B, colistin, tigecylcine and minocycline was observed. The bla OXA-23like and bla OXA-24 like were found among 77.9% and 19.2% of the isolates, respectively. All isolates were positive for bla OXA-51, but none produced any amplicon for bla OXA-58. PFGE genotype analysis suggested the existence of eight clones among the 104 strains [A (n = 35), B (n = 29), C (n = 19), D (n = 10), E (n = 4), F (n = 3), G (n = 3), H (n = 1)]. Clone A was the dominant clone in hospital settings particularly infection wards so that the isolates in this group, compared to the other clones, showed higher levels of resistance to antibiotics. Conclusion The bla OXA-51-like and bla OXA-23like were

  7. Global Gene Expression Profiles of Resistant and Susceptible Genotypes of Glycine tomentella During Phakopsora pachyrhizi Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean rust, caused by Phakopsora pachyrhizi, is a destructive foliar disease that occurs in many soybean-producing countries. Towards the goal of identifying genes controlling resistance to soybean rust, transcriptome profiling was conducted in resistant and susceptible Glycine tomentella genotype...

  8. Molecular Epidemiology and Antibiotic Susceptibility of Vibrio cholerae Associated with a Large Cholera Outbreak in Ghana in 2014

    PubMed Central

    Eibach, Daniel; Herrera-León, Silvia; Gil, Horacio; Hogan, Benedikt; Ehlkes, Lutz; Adjabeng, Michael; Kreuels, Benno; Nagel, Michael; Opare, David; Fobil, Julius N; May, Jürgen

    2016-01-01

    Background Ghana is affected by regular cholera epidemics and an annual average of 3,066 cases since 2000. In 2014, Ghana experienced one of its largest cholera outbreaks within a decade with more than 20,000 notified infections. In order to attribute this rise in cases to a newly emerging strain or to multiple simultaneous outbreaks involving multi-clonal strains, outbreak isolates were characterized, subtyped and compared to previous epidemics in 2011 and 2012. Methodology/Principal Findings Serotypes, biotypes, antibiotic susceptibilities were determined for 92 Vibrio cholerae isolates collected in 2011, 2012 and 2014 from Southern Ghana. For a subgroup of 45 isolates pulsed-field gel electrophoresis, multilocus sequence typing and multilocus-variable tandem repeat analysis (MLVA) were performed. Eighty-nine isolates (97%) were identified as ctxB (classical type) positive V. cholerae O1 biotype El Tor and three (3%) isolates were cholera toxin negative non-O1/non-O139 V. cholerae. Among the selected isolates only sulfamethoxazole/trimethoprim resistance was detectable in 2011, while 95% of all 2014 isolates showed resistance towards sulfamethoxazole/trimethoprim, ampicillin and reduced susceptibility to ciprofloxacin. MLVA achieved the highest subtype discrimination, revealing 22 genotypes with one major outbreak cluster in each of the three outbreak years. Apart from those clusters genetically distant genotypes circulate during each annual epidemic. Conclusions/Significance This analysis suggests different endemic reservoirs of V. cholerae in Ghana with distinct annual outbreak clusters accompanied by the occurrence of genetically distant genotypes. Preventive measures for cholera transmission should focus on aquatic reservoirs. Rapidly emerging multidrug resistance must be monitored closely. PMID:27232338

  9. Investigation into the potential of sub-lethal photodynamic antimicrobial chemotherapy (PACT) to reduce susceptibility of meticillin-resistant Staphylococcus aureus (MRSA) to antibiotics

    NASA Astrophysics Data System (ADS)

    Cassidy, C. M.; Donnelly, R. F.; Tunney, M. M.

    2009-06-01

    In PACT, a combination of a sensitising drug and visible light cause the selective destruction of microbial cells via singlet oxygen production. As singlet oxygen is a non-specific oxidizing agent and is only present during illumination, development of resistance to this treatment is thought to be unlikely. However, in response to oxidative stress, bacteria can up-regulate oxidative stress genes and associated antibiotic resistance genes. The up-regulation of these genes and potential transfer of genetic material may result in a resistant bacterial population. This study determined whether treatment of clinically isolated meticillin resistant Staphylococcus aureus (MRSA) strains with sub-lethal doses of methylene blue (MB) and meso-tetra (N-methyl-4-pyridyl) porphine tetra tosylate (TMP)-PACT resulted in reduced susceptibility to antibiotics and previously lethal PACT. Exposure of strains to sub-lethal doses of photosensitizer in combination with light had no effect on susceptibility to previously lethal photosensitization. Furthermore, exposure to sub-lethal concentrations of both photosensitizers caused no significant changes in the minimum inhibitory concentration (MIC) for each strain tested. Any differences in susceptibility were not significant as they did not cross breakpoints between resistant and susceptible for any organism or antibiotic tested. Therefore, PACT remains an attractive alternative option for treatment of MRSA infections.

  10. [Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (2006)].

    PubMed

    Goto, Hajime; Takeda, Hideki; Kawai, Shin; Suwabe, Akira; Watanabe, Suguru; Okazaki, Mitsuhiro; Ashino, Yugo; Shimada, Kaoru; Aoki, Nobuki; Sato, Tetsuo; Honma, Yasuo; Mori, Takeshi; Kudo, Kouichiro; Sugiyama, Haruhito; Kondo, Shigemi; Tanaka, Tsukasa; Kido, Kenji; Yoshimura, Kunihiko; Oguri, Toyoko; Yamamoto, Makoto; Nakamori, Yoshitaka; Inoue, Hiroshi; Yamauchi, Kohei; Sumitomo, Midori; Endo, Shigeatsu; Nakadate, Toshihide; Oka, Mikio; Kobashi, Yoshihiro; Saita, Naoki; Yanagihara, Katsunori; Kondou, Akira; Matsuda, Junichi; Nakano, Michiko; Kohno, Shigeru; Oikawa, Satoru

    2013-12-01

    From October 2006 to September 2007, we collected the specimen from 356 patients with lower respiratory tract infections in 14 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and patients' characteristics. Of 414 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in infection, 407 strains were examined. The isolated bacteria were: Staphylococcus aureus 64, Streptococcus pneumoniae 96, Haemophilus influenzae 87, Pseudomonas aeruginosa (non-mucoid) 52, P. aeruginosa (mucoid) 11, Klebsiella pneumoniae 20, and Moraxella catarrhalis 44. Of 64 S. aureus strains, those with 2 microg/ml or less of MIC of oxacillin (methicillin-susceptible S. aureus: MSSA) and those with 4 microg/ml or more of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) were 27 (42.2%) and 37 (57.8%) strains, respectively. Against MSSA, imipenem had the most potent antibacterial activity and inhibited the growth of all strains at 0.063 microg/ml or less. Against MRSA, vancomycin and linezolid showed the most potent activity and inhibited the growth of all the strains at 1 microg/ml. Carbapenems showed the most potent activities against S. pneumoniae and in particular, panipenem inhibited the growth of all the strains at 0.063 microg/ml or less. Imipenem and faropenem also had a preferable activity and inhibited the growth of all the strains at 0.125 and 0.5 microg/ml, respectively. In contrast, there were high-resistant strains (MIC: over 128 microg/ml) for erythromycin (45.8%) and clindamycin (20.8%). Against H. influenzae, levofloxacin showed the most potent activity and its MIC90 was 0.063 microg/ml or less. Meropenem showed the most potent activity against P. aeruginosa (mucoid) and its MIC90 was 0.5 microg/ml. Against P. aeruginosa (non-mucoid), tobramycin had the most potent activity and its MIC90 was 2 microg/ml. Against K. pneumoniae, cefozopran was the most potent activity

  11. [Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (2005)].

    PubMed

    Goto, Hajime; Takeda, Hideki; Kawai, Shin; Watanabe, Suguru; Okazaki, Mitsuhiro; Shimada, Kaoru; Nakano, Kunio; Yokouchi, Hiroshi; Mori, Takeshi; Igari, Jun; Oguri, Toyoko; Yamamoto, Makoto; Kudo, Kolichiro; Kobayashi, Nobuyuki; Tanaka, Tsukasa; Yoshimura, Kunihiko; Kawabata, Masaaki; Nakamori, Yoshitaka; Sumitomo, Midori; Inoue, Hiroshi; Nakadate, Toshihide; Suwabe, Akira; Ashino, Yugo; Aoki, Nobuki; Honma, Yasuo; Suzuki, Yasutoshi; Karasawa, Yasuo; Oka, Mikio; Kobashi, Yoshihiro; Kohno, Shigeru; Hirakata, Yoichi; Kondou, Akira; Matsuda, Junichi; Nakano, Michiko; Oikawa, Satoru

    2008-08-01

    From October 2005 to September 2006, we collected the specimen from 366 patients with lower respiratory tract infections in 12 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and patients' characteristics. Of 411 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in infection, 406 strains were examined. The isolated bacteria were: Staphylococcus aureus 70, Streptococcus pneumoniae 85, Haemophilus influenzae 78, Pseudomonas aeruginosa (non-mucoid) 46, P. aeruginosa (mucoid) 14, Klebsiella pneumoniae 21, and Moraxella subgenus Branhamella catarrhalis 40. Of 70 S. aureus strains, those with 2 microg/ml or less of MIC of oxacillin (methicillin-susceptible S. aureus: MSSA) and those with 4 microg/ml or more of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) were 38 (54.3%) and 32 (45.7%) strains, respectively. Against MSSA, imipenem had the most potent antibacterial activity and inhibited the growth of 37 strains (97.4%) at 0.063 microg/ml or less. Against MRSA, arbekacin and vancomycin showed the most potent activity and inhibited the growth of all the strains at 1 microg/ml. Carbapenems showed the most potent activities against S. pneumoniae and in particular, panipenem inhibited the growth of all the strains at 0.063 microg/ml or less. Faropenem also had a preferable activity and inhibited the growth of all the strains at 0.25 microg/ml. In contrast, there were high-resistant strains (MIC: over 128 microg/ml) for erythromycin (38.1%) and clindamycin (22.6%). Against H. influenzae, levofloxacin showed the most potent activity and its MIC90 was 0.063 microg/ml or less. Meropenem showed the most potent activity against P. aeruginosa (mucoid) and its MIC90 was 0.5 microg/ml. Against P. aeruginosa (non-mucoid), arbekacin had the most potent activity and its MIC90 was 8 microg/ml. Against K. pneumoniae, cefozopran was the most potent activity and

  12. Prevalence, molecular characterization, and antibiotic susceptibility of Cronobacter spp. in Chinese ready-to-eat foods.

    PubMed

    Xu, Xiaoke; Li, Chengsi; Wu, Qingping; Zhang, Jumei; Huang, Jiahui; Yang, Guangzhu

    2015-07-01

    Cronobacter spp. are foodborne pathogens that cause rare but life-threatening diseases in neonates and infants; they can also cause disease in adults. Cronobacter spp. contamination of ready-to-eat (RTE) foods has been reported previously. However, to date, the prevalence and contamination levels of these bacteria in RTE foods in China have not yet been determined. Therefore, the aim of this study was to investigate the prevalence of Cronobacter spp. in RTE foods marketed in China. Two-hundred and eighty RTE food samples were collected from different producers and retailers and analyzed using quantitative methods. The isolates obtained were identified to the species level based on fusA sequences, and were subtyped using a PCR-based serotyping technique. Selected isolates were further characterized by multilocus sequence typing (MLST) and antimicrobial sensitivity determination. Of 280 samples tested, 52 (18.6%) were positive for Cronobacter spp. The contamination levels were less than 110 MPN/g for 78.8% (41/52) of the samples. The results of the O-antigen serotyping for 111 isolates showed that Cronobacter sakazakii serogroup O2 (28 isolates) was the most prevalent serotype. MLST analyses produced 41 sequence types (STs), including 20 novel STs. ST8 was the most prevalent ST (9 isolates) followed by ST4 (5 isolates). Antimicrobial sensitivity testing showed that 84.5% and 46.5% of the isolates were resistant to penicillin G and cephalothin, respectively; in contrast, all of the tested isolates were susceptible to cefotaxime, ciprofloxacin, tetracycline, and nalidixic acid. To the best of our knowledge, this is the first report on Cronobacter spp. prevalence in RTE foods in China, and the findings of our study nonetheless suggested that Cronobacter spp. contamination of Chinese RTE foods poses a potential risk for the consumer. Thus, the study highlights the significance of developing more effective control strategies during the manufacturing process. PMID:25828706

  13. Polymorphic Variation in Susceptibility and Metabolism of Triclosan-Resistant Mutants of Escherichia coli and Klebsiella pneumoniae Clinical Strains Obtained after Exposure to Biocides and Antibiotics

    PubMed Central

    Curiao, Tânia; Marchi, Emmanuela; Viti, Carlo; Oggioni, Marco R.; Baquero, Fernando; Martinez, José Luis

    2015-01-01

    Exposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selected Escherichia coli and Klebsiella pneumoniae mutants. E. coli and K. pneumoniae mutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of the fabI gene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRIr) and triclosan-hypersusceptible (TRIhs) mutants of E. coli and K. pneumoniae were obtained after selection with biocides and/or antibiotics. E. coli TRIr mutants, including those with mutations in the fabI gene or in the expression of acrB, acrF, and marA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRIr mutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRIr mutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRIr mutants had fitness costs, particularly marA-overexpressing (E. coli) or ramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRIr mutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive traits. PMID

  14. Differential Effects of Penicillin Binding Protein Deletion on the Susceptibility of Enterococcus faecium to Cationic Peptide Antibiotics

    PubMed Central

    Kumaraswamy, Monika; Nonejuie, Poochit; Werth, Brian J.; Rybak, Micahel J.; Pogliano, Joseph; Rice, Louis B.; Nizet, Victor

    2015-01-01

    Beta-lactam antibiotics sensitize Enterococcus faecium to killing by endogenous antimicrobial peptides (AMPs) of the innate immune system and daptomycin through mechanisms yet to be elucidated. It has been speculated that beta-lactam inactivation of select E. faecium penicillin binding proteins (PBPs) may play a pivotal role in this sensitization process. To characterize the specific PBP inactivation that may be responsible for these phenotypes, we utilized a previously characterized set of E. faecium PBP knockout mutants to determine the effects of such mutations on the activity of daptomycin and the AMP human cathelicidin (LL-37). Enhanced susceptibility to daptomycin was dependent more on a cumulative effect of multiple PBP deletions than on inactivation of any single specific PBP. Selective knockout of PBPZ rendered E. faecium more vulnerable to killing by both recombinant LL-37 and human neutrophils, which produce the antimicrobial peptide in high quantities. Pharmacotherapy targeting multiple PBPs may be used as adjunctive therapy with daptomycin to treat difficult E. faecium infections. PMID:26195528

  15. Gene expression profiling of Naïve sheep genetically resistant and susceptible to gastrointestinal nematodes

    PubMed Central

    Keane, Orla M; Zadissa, Amonida; Wilson, Theresa; Hyndman, Dianne L; Greer, Gordon J; Baird, David B; McCulloch, Alan F; Crawford, Allan M; McEwan, John C

    2006-01-01

    Background Gastrointestinal nematodes constitute a major cause of morbidity and mortality in grazing ruminants. Individual animals or breeds, however, are known to differ in their resistance to infection. Gene expression profiling allows us to examine large numbers of transcripts simultaneously in order to identify those transcripts that contribute to an animal's susceptibility or resistance. Results With the goal of identifying genes with a differential pattern of expression between sheep genetically resistant and susceptible to gastrointestinal nematodes, a 20,000 spot ovine cDNA microarray was constructed. This array was used to interrogate the expression of 9,238 known genes in duodenum tissue of four resistant and four susceptible female lambs. Naïve animals were used in order to look at genes that were differentially expressed in the absence of infection with gastrointestinal nematodes. Forty one unique known genes were identified that were differentially expressed between the resistant and susceptible animals. Northern blotting of a selection of the genes confirmed differential expression. The differentially expressed genes had a variety of functions, although many genes relating to the stress response and response to stimulus were more highly expressed in the susceptible animals. Conclusion We have constructed the first reported ovine microarray and used this array to examine gene expression in lambs genetically resistant and susceptible to gastrointestinal nematode infection. This study indicates that susceptible animals appear to be generating a hyper-sensitive immune response to non-nematode challenges. The gastrointestinal tract of susceptible animals is therefore under stress and compromised even in the absence of gastrointestinal nematodes. These factors may contribute to the genetic susceptibility of these animals. PMID:16515715

  16. Characterisation of Phenotypic and Genotypic Antibiotic Resistance Profile of Enterococci from Cheeses in Turkey.

    PubMed

    Kürekci, Cemil; Önen, Sevda Pehlivanlar; Yipel, Mustafa; Aslantaş, Özkan; Gündoğdu, Aycan

    2016-01-01

    The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3')-IIIa, ant(6)-Ia and aac(6')-Ieaph(2")-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey. PMID:27433106

  17. Characterisation of Phenotypic and Genotypic Antibiotic Resistance Profile of Enterococci from Cheeses in Turkey

    PubMed Central

    Yipel, Mustafa; Aslantaş, Özkan; Gündoğdu, Aycan

    2016-01-01

    The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3’)-IIIa, ant(6)-Ia and aac(6’)-Ieaph(2”)-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey. PMID:27433106

  18. Bacterial fitness shapes the population dynamics of antibiotic-resistant and -susceptible bacteria in a model of combined antibiotic and anti-virulence treatment

    PubMed Central

    Ternent, Lucy; Dyson, Rosemary J.; Krachler, Anne-Marie; Jabbari, Sara

    2015-01-01

    Bacterial resistance to antibiotic treatment is a huge concern: introduction of any new antibiotic is shortly followed by the emergence of resistant bacterial isolates in the clinic. This issue is compounded by a severe lack of new antibiotics reaching the market. The significant rise in clinical resistance to antibiotics is especially problematic in nosocomial infections, where already vulnerable patients may fail to respond to treatment, causing even greater health concern. A recent focus has been on the development of anti-virulence drugs as a second line of defence in the treatment of antibiotic-resistant infections. This treatment, which weakens bacteria by reducing their virulence rather than killing them, should allow infections to be cleared through the body׳s natural defence mechanisms. In this way there should be little to no selective pressure exerted on the organism and, as such, a predominantly resistant population should be less likely to emerge. However, before the likelihood of resistance to these novel drugs emerging can be predicted, we must first establish whether such drugs can actually be effective. Many believe that anti-virulence drugs would not be powerful enough to clear existing infections, restricting their potential application to prophylaxis. We have developed a mathematical model that provides a theoretical framework to reveal the circumstances under which anti-virulence drugs may or may not be successful. We demonstrate that by harnessing and combining the advantages of antibiotics with those provided by anti-virulence drugs, given infection-specific parameters, it is possible to identify treatment strategies that would efficiently clear bacterial infections, while preventing the emergence of antibiotic-resistant subpopulations. Our findings strongly support the continuation of research into anti-virulence drugs and demonstrate that their applicability may reach beyond infection prevention. PMID:25701634

  19. PCR-based identification of methicillin-resistant Staphylococcus aureus strains and their antibiotic resistance profiles

    PubMed Central

    Pournajaf, Abazar; Ardebili, Abdollah; Goudarzi, Leyla; Khodabandeh, Mahmoud; Narimani, Tahmineh; Abbaszadeh, Hassan

    2014-01-01

    Objective To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates. Results Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay. Conclusions This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic. PMID:25183100

  20. Antibiotic susceptibility rates of invasive pneumococci before and after the introduction of pneumococcal conjugate vaccination in Germany.

    PubMed

    Imöhl, Matthias; Reinert, Ralf René; van der Linden, Mark

    2015-10-01

    .4%, resistant 0.3%), 8.5% for tetracycline (intermediate 0.6%, resistant 7.9%) and 11.0% for trimethoprim-sulfamethoxazole (SXT) (intermediate 5.7%, resistant 5.3%). In summary, childhood pneumococcal conjugate vaccination has had a strong effect on the pneumococcal population in Germany, both among vaccinated children as well as among non-vaccinated children and adults. Serotypes included in the pneumococcal conjugate vaccines have strongly diminished, while some non-vaccine serotypes have gained importance, particularly with respect to antibiotic resistance. However, concerning antibiotic non-susceptibility the most outstanding change over the years is the decline in macrolide resistance, especially among children. PMID:26324014

  1. Identification of Tuberculosis Susceptibility Genes with Human Macrophage Gene Expression Profiles

    PubMed Central

    Chau, Tran Thi Hong; Thorsson, Vesteinn; Simmons, Cameron P.; Quyen, Nguyen Than Ha; Thwaites, Guy E.; Thi Ngoc Lan, Nguyen; Hibberd, Martin; Teo, Yik Y.; Seielstad, Mark; Aderem, Alan; Farrar, Jeremy J.; Hawn, Thomas R.

    2008-01-01

    Although host genetics influences susceptibility to tuberculosis (TB), few genes determining disease outcome have been identified. We hypothesized that macrophages from individuals with different clinical manifestations of Mycobacterium tuberculosis (Mtb) infection would have distinct gene expression profiles and that polymorphisms in these genes may also be associated with susceptibility to TB. We measured gene expression levels of >38,500 genes from ex vivo Mtb-stimulated macrophages in 12 subjects with 3 clinical phenotypes: latent, pulmonary, and meningeal TB (n = 4 per group). After identifying differentially expressed genes, we confirmed these results in 34 additional subjects by real-time PCR. We also used a case-control study design to examine whether polymorphisms in differentially regulated genes were associated with susceptibility to these different clinical forms of TB. We compared gene expression profiles in Mtb-stimulated and unstimulated macrophages and identified 1,608 and 199 genes that were differentially expressed by >2- and >5-fold, respectively. In an independent sample set of 34 individuals and a subset of highly regulated genes, 90% of the microarray results were confirmed by RT-PCR, including expression levels of CCL1, which distinguished the 3 clinical groups. Furthermore, 6 single nucleotide polymorphisms (SNPs) in CCL1 were found to be associated with TB in a case-control genetic association study with 273 TB cases and 188 controls. To our knowledge, this is the first identification of CCL1 as a gene involved in host susceptibility to TB and the first study to combine microarray and DNA polymorphism studies to identify genes associated with TB susceptibility. These results suggest that genome-wide studies can provide an unbiased method to identify critical macrophage response genes that are associated with different clinical outcomes and that variation in innate immune response genes regulate susceptibility to TB. PMID:19057661

  2. PREVALENCE, BIOCHEMICAL CHARACTERISTICS, AND ANTIBIOTIC SUSCEPTIBILITY OF AEROMONADS, VIBRIOS, AND PLESIOMONADS ISOLATED FROM DIFFERENT SOURCES AT A ZOO.

    PubMed

    Kim, Kyoo-Tae; Lee, Seung-Hun; Kwak, Dongmi

    2015-06-01

    Aeromonas spp., Vibrio parahaemolyticus , and Plesiomonas shigelloides are commonly implicated in foodborne and waterborne diarrheal illnesses of humans and other animals. The present study assessed the prevalence, biochemical characteristics, and antibiotic susceptibility of Aeromonas spp., V. parahaemolyticus , and P. shigelloides by analyzing samples from 729 sources at a zoo, including animal feces (n=607), watering facilities (n=104), and pond water samples (n=18). Of the 729 samples collected, 40 (5.5%) contained one of these four species of bacteria: A. hydrophila (n=16; 2.2%), A. sobria (n=12; 1.6%), V. parahaemolyticus (n=10; 1.4%), and P. shigelloides (n=2; 0.3%). The 16 isolates of A. hydrophila came from three fecal samples, eight watering facilities, and five pond water samples. The 12 isolates of A. sobria came from four fecal samples, three watering facilities, and five pond water samples. The 10 isolates of V. parahaemolyticus came from one fecal sample and nine watering facilities. The two isolates of P. shigelloides came from one watering facility and one pond water sample. Of the 40 isolates, 16 (40.0%), 21 (52.5%), and three (7.5%) originated from mammals, birds, and reptiles, respectively. All isolates tested positive for NO3, tryptophan, p-nitrophenyl-β-D-galactopyranoside, glucose assimilation, N-acetyl-glucosamine, maltose, gluconate, malate, and oxidase. Aeromonas spp. and V. parahaemolyticus exhibited similar biochemical characteristics, whereas P. shigelloides exhibited distinct fermentation characteristics. All the isolated strains exhibited hemolytic activity; variable results of DNase, protease, and Congo red uptake tests; and resistance to ampicillin, bacitracin, novobiocin, penicillin, and vancomycin. All the strains were sensitive to amikacin, chloramphenicol, colistin, gentamicin, kanamycin, norfloxacin, and trimethoprim-sulfadimethoxazole. Because of the high proportion of asymptomatic carriers of these potentially pathogenic

  3. Standardization of Operator-Dependent Variables Affecting Precision and Accuracy of the Disk Diffusion Method for Antibiotic Susceptibility Testing.

    PubMed

    Hombach, Michael; Maurer, Florian P; Pfiffner, Tamara; Böttger, Erik C; Furrer, Reinhard

    2015-12-01

    Parameters like zone reading, inoculum density, and plate streaking influence the precision and accuracy of disk diffusion antibiotic susceptibility testing (AST). While improved reading precision has been demonstrated using automated imaging systems, standardization of the inoculum and of plate streaking have not been systematically investigated yet. This study analyzed whether photometrically controlled inoculum preparation and/or automated inoculation could further improve the standardization of disk diffusion. Suspensions of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 of 0.5 McFarland standard were prepared by 10 operators using both visual comparison to turbidity standards and a Densichek photometer (bioMérieux), and the resulting CFU counts were determined. Furthermore, eight experienced operators each inoculated 10 Mueller-Hinton agar plates using a single 0.5 McFarland standard bacterial suspension of E. coli ATCC 25922 using regular cotton swabs, dry flocked swabs (Copan, Brescia, Italy), or an automated streaking device (BD-Kiestra, Drachten, Netherlands). The mean CFU counts obtained from 0.5 McFarland standard E. coli ATCC 25922 suspensions were significantly different for suspensions prepared by eye and by Densichek (P < 0.001). Preparation by eye resulted in counts that were closer to the CLSI/EUCAST target of 10(8) CFU/ml than those resulting from Densichek preparation. No significant differences in the standard deviations of the CFU counts were observed. The interoperator differences in standard deviations when dry flocked swabs were used decreased significantly compared to the differences when regular cotton swabs were used, whereas the mean of the standard deviations of all operators together was not significantly altered. In contrast, automated streaking significantly reduced both interoperator differences, i.e., the individual standard deviations, compared to the standard deviations for the manual method, and the mean of

  4. Antifungal susceptibility profiles of 1698 yeast reference strains revealing potential emerging human pathogens.

    PubMed

    Desnos-Ollivier, Marie; Robert, Vincent; Raoux-Barbot, Dorothée; Groenewald, Marizeth; Dromer, Françoise

    2012-01-01

    New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites) were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes). Interestingly, geometric mean minimum inhibitory concentrations (MICs) of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001). Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically "resistant" to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens. PMID:22396754

  5. Shift in antibiotic resistance gene profiles associated with nanosilver during wastewater treatment.

    PubMed

    Ma, Yanjun; Metch, Jacob W; Yang, Ying; Pruden, Amy; Zhang, Tong

    2016-03-01

    This study investigated the response of antibiotic resistance genes (ARGs) to nanosilver (Ag) in lab-scale nitrifying sequencing batch reactors (SBRs), compared to Ag(+)-dosed and undosed controls. Quantitative polymerase chain reaction (q-PCR) targeting sul1, tet(O), ermB and the class I integron gene intI1 and corresponding RNA expression did not indicate measureable effects of nanoAg or Ag(+) on abundance or expression of these genes. However, high-throughput sequencing based metagenomic analysis provided a much broader profile of gene responses and revealed a greater abundance of aminoglycoside resistance genes (mainly strA) in reactors dosed with nanoAg. In contrast, bacitracin and macrolide-lincosamide-streptogramin (MLS) resistance genes were more abundant in the SBRs dosed with Ag(+). The distinct ARG profiles associated with nanoAg and Ag(+) were correlated with the taxonomic composition of the microbial communities. This study indicates that nanoAg may interact with bacteria differently from Ag(+) during biological wastewater treatment. Therefore, it cannot necessarily be assumed that nanosilver behaves identically as Ag(+) when conducting a risk assessment for release into the environment. PMID:26850160

  6. The Quorum Sensing Inhibitor Hamamelitannin Increases Antibiotic Susceptibility of Staphylococcus aureus Biofilms by Affecting Peptidoglycan Biosynthesis and eDNA Release

    PubMed Central

    Brackman, Gilles; Breyne, Koen; De Rycke, Riet; Vermote, Arno; Van Nieuwerburgh, Filip; Meyer, Evelyne; Van Calenbergh, Serge; Coenye, Tom

    2016-01-01

    Treatment of Staphylococcus aureus infections has become increasingly challenging due to the rapid emergence and dissemination of methicillin-resistant strains. In addition, S. aureus reside within biofilms at the site of infection. Few novel antibacterial agents have been developed in recent years and their bacteriostatic or bactericidal activity results in selective pressure, inevitably inducing antimicrobial resistance. Consequently, innovative antimicrobials with other modes of action are urgently needed. One alternative approach is targeting the bacterial quorum sensing (QS) system. Hamamelitannin (2′,5-di-O-galloyl-d-hamamelose; HAM) was previously suggested to block QS through the TraP QS system and was shown to increase S. aureus biofilm susceptibility towards vancomycin (VAN) although mechanistic insights are still lacking. In the present study we provide evidence that HAM specifically affects S. aureus biofilm susceptibility through the TraP receptor by affecting cell wall synthesis and extracellular DNA release of S. aureus. We further provide evidence that HAM can increase the susceptibility of S. aureus biofilms towards different classes of antibiotics in vitro. Finally, we show that HAM increases the susceptibility of S. aureus to antibiotic treatment in in vivo Caenorhabditis elegans and mouse mammary gland infection models. PMID:26828772

  7. Effects of moxifloxacin exposure on the conjunctival flora and antibiotic resistance profile following repeated intravitreal injections

    PubMed Central

    Ataş, Mustafa; Başkan, Burhan; Özköse, Ayşe; Mutlu Sarıgüzel, Fatma; Demircan, Süleyman; Pangal, Emine

    2014-01-01

    AIM To evaluate the effects of moxifloxacin exposure on the conjunctival flora and antibiotic resistance profile following repeated intravitreal injections. METHODS Seventy-two eyes of 36 patients [36 eyes in control group, 36 eyes in intravitreal injection (IVI) group] were enrolled in the study. All the eyes had at least one IVI and had diabetic macular edema (DME) or age-related macular degeneration (ARMD). Moxifloxacin was prescribed to all the patients four times a day for five days following injection. Conjunctival cultures were obtained from the lower fornix via standardized technique with every possible effort made to minimize contamination from the lids, lashes, or skin. Before the application of any ophthalmic medication, conjunctival cultures were obtained from both eyes using sterile cotton culture. An automated microbiology system was used to identify the growing bacteria and determine antibiotic sensitivity. RESULTS The bacterial cultures were isolated from 72 eyes of 36 patients, sixteen of whom patients (44.4%) were male and twenty (55.6%) were female. Average age was 68.4±9.0 (range 50-86). The average number of injections before taking cultures was 3.1+1.0. Forty-eight (66.7%) of 72 eyes had at least one significant organism. There was no bacterial growth in 8 (20.5%) of IVI eyes and in 16 (44.4%) of control eyes (P=0.03). Of the bacteria isolated from culture, 53.8% of coagulase negative staphylococci (CoNS) in IVI eyes and 47.2% CoNS in control eyes. This difference between IVI eyes and control eyes about bacteria isolated from culture was not statistically significant (P=0.2). Eleven of 25 bacteria (44.0%) isolated from IVI eyes and 11 (57.9%) of 19 bacteria isolated from control eyes were resistant to oxacillin. The difference in frequency of moxifloxacine resistance between two groups was not statistically significant (12.0% in IVI eyes and 21.1% in control eyes) (P=0.44). There were no cases of resistance to vancomycin, teicoplanin and

  8. [Characterization and determination of antibiotic resistance profiles of a single clone Acinetobacter baumannii strains isolated from blood cultures].

    PubMed

    Karagöz, Alper; Baran, Irmak; Aksu, Neriman; Acar, Sümeyra; Durmaz, Rıza

    2014-10-01

    Acinetobacter baumannii which is a significant cause of nosocomial infections, increases the rate of morbidity and mortality in health care settings especially in intensive care units (ICUs). The aim of this study was to determine the antibiotic resistance profiles of A.baumannii strains isolated from blood cultures of inpatients from different ICUs, wards and hospital environment and evaluate their clonal relationships and epidemiologic features. A total of 54 A.baumannii strains (47 from the blood cultures and 7 from the hospital environment), identified between 01 January 2012-28 December 2012 at the Clinical Microbiology Laboratory of Ankara Numune Training and Research Hospital, Turkey, were included in the study. Identification of A.baumannii isolates and their antimicrobial [sulbactam-ampicillin (SAM), piperacillin (PIP), piperacillin-tazobactam (TZP), ceftazidime (CFZ), cefoperazone-sulbactam (SCF), cefepime (CEF), imipenem (IMP), meropenem (MER), amikacin (AMK), gentamicin (GEN), netilmicin (NT), ciprofloxacin (CIP), levofloxacin (LVF), tetracycline (TET), tigecycline (TG), colistin (COL), trimethoprim-sulfamethoxazole (SXT)] susceptibility testing were performed by Vitek 2 (bioMérieux, France) system. The clonal relationship between the A.baumannii isolates was analysed by pulsed-field gel electrophoresis (PFGE). In our study colistin, tigecycline and netilmicin were found to be the most effective agents against A.baumannii isolates. All of the clinical isolates (n= 47) were found susceptible to COL, however all were resistant to SAM, PIP, TZP, CEF, IPM, CFZ, MER and CIP. While 1.85%, 14.8%, 14.8%, 16.6%, 59.2% and 22.2% of the isolates were susceptible to SCF, AMK, NT, GEN, TG and SXT, respectively; 1.85%, 1.85%, 9.2%, 16.6%, 38.8% and 27.7% of the isolates were intermediate to SCF, TET, AMK, NT, LVF and TG, respectively. Similarly, all of the environmental A.baumannii isolates (n= 7) were resistant to SAM, PIP, TZP, CFZ, CEF, IPM, MER and CIP, and all

  9. Polymorphic variation in susceptibility and metabolism of triclosan-resistant mutants of Escherichia coli and Klebsiella pneumoniae clinical strains obtained after exposure to biocides and antibiotics.

    PubMed

    Curiao, Tânia; Marchi, Emmanuela; Viti, Carlo; Oggioni, Marco R; Baquero, Fernando; Martinez, José Luis; Coque, Teresa M

    2015-01-01

    Exposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selected Escherichia coli and Klebsiella pneumoniae mutants. E. coli and K. pneumoniae mutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of the fabI gene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRI(r)) and triclosan-hypersusceptible (TRI(hs)) mutants of E. coli and K. pneumoniae were obtained after selection with biocides and/or antibiotics. E. coli TRI(r) mutants, including those with mutations in the fabI gene or in the expression of acrB, acrF, and marA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRI(r) mutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRI(r) mutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRI(r) mutants had fitness costs, particularly marA-overexpressing (E. coli) or ramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRI(r) mutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive

  10. Association of multiple-antibiotic-resistance profiles with point and nonpoint sources of Escherichia coli in Apalachicola Bay.

    PubMed

    Parveen, S; Murphree, R L; Edmiston, L; Kaspar, C W; Portier, K M; Tamplin, M L

    1997-07-01

    A total of 765 Escherichia coli isolates from point and nonpoint sources were collected from the Apalachicola National Estuarine Research Reserve, and their multiple-antibiotic-resistance (MAR) profiles were determined with 10 antibiotics. E. coli isolates from point sources showed significantly greater resistance (P < 0.05) to antibiotics and higher MAR indices than isolates from nonpoint sources. Specifically, 65 different resistance patterns were observed among point source isolates, compared to 32 among nonpoint source isolates. Examples of this contrast in MAR profiles included percentages of isolates with resistance to chlortetracycline-sulfathiazole of 33.7% and to chlortetracycline-penicillin G-sulfathiazole of 14.5% for point source isolates versus 15.4 and 1.7%, respectively, for nonpoint source isolates. MAR profile homology, based on coefficient similarity, showed that isolates from point sources were markedly more diverse than isolates from nonpoint sources. Seven clusters were observed among point source isolates, with a coefficient value of approximately 1.8. In contrast, only four clusters were observed among nonpoint source isolates. Covariance matrices of data displayed six very distinct foci representing nonpoint source E. coli isolates. Importantly, E. coli isolates obtained directly from human and animal feces also clustered among point and nonpoint sources, respectively. We conclude that E. coli MAR profiles were associated with point and nonpoint sources of pollution within Apalachicola Bay and that this method may be useful in facilitating management of other estuaries. PMID:9212410

  11. Antibiotic Susceptibility of Staphylococcus aureus in Atopic Dermatitis: Current Prevalence of Methicillin-Resistant Staphylococcus aureus in Korea and Treatment Strategies

    PubMed Central

    Jung, Mi-Young; Chung, Jong-Youn; Lee, Hae-Young; Park, Jiho; Lee, Dong-Youn

    2015-01-01

    Background Staphylococcus aureus is a well-known microbe that colonizes or infects the skin in atopic dermatitis (AD). The prevalence of methicillin-resistant S. aureus (MRSA) in AD has recently been increasing. Objective This study aimed to determine the antimicrobial susceptibility patterns in AD skin lesions and evaluate the prevalence of MRSA in Korea. We also recommend proper first-line topical antibiotics for Korean patients with AD. Methods We studied S. aureus-positive skin swabs (n=583) from the lesional skin of infants, children, and adults who presented to our outpatient clinic with AD from July 2009 to April 2012. Results S. aureus exhibited high susceptibility against most antimicrobial agents. However, it exhibited less susceptibility to benzylpenicillin, erythromycin, clindamycin, and fusidic acid. The prevalence of MRSA was 12.9% among 583 S. aureus isolates, and the susceptibility to oxacillin was significantly lower in infants in both acute and chronic AD lesions. Conclusion S. aureus from AD has a high prevalence of MRSA and multidrug resistance, especially in infants. In addition, the rate of fusidic acid resistance is high among all age groups, and mupirocin resistance increases with age group regardless of lesional status. This is the first study comparing the antimicrobial susceptibility rates of S. aureus isolates from AD cases with respect to age and lesion status in Korea. PMID:26273155

  12. Use of plasmid profiles in epidemiologic surveillance of disease outbreaks and in tracing the transmission of antibiotic resistance.

    PubMed Central

    Mayer, L W

    1988-01-01

    Plasmids are circular deoxyribonucleic acid molecules that exist in bacteria, usually independent of the chromosome. The study of plasmids is important to medical microbiology because plasmids can encode genes for antibiotic resistance or virulence factors. Plasmids can also serve as markers of various bacterial strains when a typing system referred to as plasmid profiling, or plasmid fingerprinting is used. In these methods partially purified plasma deoxyribonucleic acid species are separated according to molecular size by agarose gel electrophoresis. In a second procedure, plasmid deoxyribonucleic acid which has been cleaved by restriction endonucleases can be separated by agarose gel electrophoresis and the resulting pattern of fragments can be used to verify the identity of bacterial isolates. Because many species of bacteria contain plasmids, plasmid profile typing has been used to investigate outbreaks of many bacterial diseases and to trace inter- and intra-species spread of antibiotic resistance. Images PMID:2852997

  13. Triclosan Can Select for an AdeIJK-Overexpressing Mutant of Acinetobacter baumannii ATCC 17978 That Displays Reduced Susceptibility to Multiple Antibiotics

    PubMed Central

    Fernando, Dinesh M.; Xu, Wayne; Loewen, Peter C.; Zhanel, George G.

    2014-01-01

    In order to determine if triclosan can select for mutants of Acinetobacter baumannii ATCC 17978 that display reduced susceptibilities to antibiotics, we isolated a triclosan-resistant mutant, A. baumannii AB042, by serial passaging of A. baumannii ATCC 17978 in growth medium supplemented with triclosan. The antimicrobial susceptibility of AB042 was analyzed by the 2-fold serial dilution method. Expression of five different resistance-nodulation-division (RND) pump-encoding genes (adeB, adeG, adeJ, A1S_2818, and A1S_3217), two outer membrane porin-encoding genes (carO and oprD), and the MATE family pump-encoding gene abeM was analyzed using quantitative reverse transcriptase (qRT) PCR. A. baumannii AB042 exhibited elevated resistance to multiple antibiotics, including piperacillin-tazobactam, doxycycline, moxifloxacin, ceftriaxone, cefepime, meropenem, doripenem, ertapenem, ciprofloxacin, aztreonam, tigecycline, and trimethoprim-sulfamethoxazole, in addition to triclosan. Genome sequencing of A. baumannii AB042 revealed a 116G→V mutation in fabI, the gene encoding the target enzyme for triclosan. Expression analysis of efflux pumps showed overexpression of the AdeIJK pump, and sequencing of adeN, the gene that encodes the repressor of the adeIJK operon, revealed a 73-bp deletion which would cause a premature termination of translation, resulting in an inactive truncated AdeN protein. This work shows that triclosan can select for mutants of A. baumannii that display reduced susceptibilities to multiple antibiotics from chemically distinct classes in addition to triclosan resistance. This multidrug resistance can be explained by the overexpression of the AdeIJK efflux pump. PMID:25136007

  14. Gene expression profiling in the thiamethoxam resistant and susceptible B-biotype sweetpotato whitefly, Bemisia tabaci.

    PubMed

    Xie, Wen; Yang, Xin; Wang, Shao-Ii; Wu, Qing-jun; Yang, Ni-na; Li, Ru-mei; Jiao, Xiao-guo; Pan, Hui-peng; Liu, Bai-ming; Feng, Yun-tao; Xu, Bao-yun; Zhou, Xu-guo; Zhang, You-jun

    2012-01-01

    Thiamethoxam has been used as a major insecticide to control the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Due to its excessive use, a high level of resistance to thiamethoxam has developed worldwide over the past several years. To better understand the molecular mechanisms underlying this resistance in B. tabaci, gene profiles between the thiamethoxam-resistant and thiamethoxam-susceptible strains were investigated using the suppression subtractive hybridization (SSH) library approach. A total of 72 and 52 upand down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These expressed sequence tags (ESTs) belong to several functional categories based on their gene ontology annotation. Some categories such as cell communication, response to abiotic stimulus, lipid particle, and nuclear envelope were identified only in the forward library of thiamethoxam-resistant strains. In contrast, categories such as behavior, cell proliferation, nutrient reservoir activity, sequence-specific DNA binding transcription factor activity, and signal transducer activity were identified solely in the reverse library. To study the validity of the SSH method, 16 differentially expressed genes from both forward and reverse SSH libraries were selected randomly for further analyses using quantitative realtime PCR (qRT-PCR). The qRT-PCR results were fairly consistent with the SSH results; however, only 50% of the genes showed significantly different expression profiles between the thiamethoxam-resistant and thiamethoxam-susceptible whiteflies. Among these genes, a putative NAD-dependent methanol dehydrogenase was substantially over-expressed in the thiamethoxamresistant adults compared to their susceptible counterparts. The distributed profiles show that it was highly expressed during the egg stage, and was most abundant in the abdomen of adult females. PMID:22957505

  15. Gene Expression Profiling in the Thiamethoxam Resistant and Susceptible B-biotype Sweetpotato Whitefly, Bemisia tabaci

    PubMed Central

    Xie, Wen; Yang, Xin; Wang, Shao-Ii; Wu, Qing-jun; Yang, Ni-na; Li, Ru-mei; Jiao, Xiaoguo; Pan, Hui-peng; Liu, Bai-ming; Feng, Yun-tao; Xu, Bao-yun; Zhou, Xu-guo; Zhang, You-jun

    2012-01-01

    Thiamethoxam has been used as a major insecticide to control the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Due to its excessive use, a high level of resistance to thiamethoxam has developed worldwide over the past several years. To better understand the molecular mechanisms underlying this resistance in B. tabaci, gene profiles between the thiamethoxam-resistant and thiamethoxam-susceptible strains were investigated using the suppression subtractive hybridization (SSH) library approach. A total of 72 and 52 upand down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These expressed sequence tags (ESTs) belong to several functional categories based on their gene ontology annotation. Some categories such as cell communication, response to abiotic stimulus, lipid particle, and nuclear envelope were identified only in the forward library of thiamethoxam-resistant strains. In contrast, categories such as behavior, cell proliferation, nutrient reservoir activity, sequence-specific DNA binding transcription factor activity, and signal transducer activity were identified solely in the reverse library. To study the validity of the SSH method, 16 differentially expressed genes from both forward and reverse SSH libraries were selected randomly for further analyses using quantitative realtime PCR (qRT-PCR). The qRT-PCR results were fairly consistent with the SSH results; however, only 50% of the genes showed significantly different expression profiles between the thiamethoxam-resistant and thiamethoxam-susceptible whiteflies. Among these genes, a putative NAD-dependent methanol dehydrogenase was substantially over-expressed in the thiamethoxamresistant adults compared to their susceptible counterparts. The distributed profiles show that it was highly expressed during the egg stage, and was most abundant in the abdomen of adult females. PMID:22957505

  16. Rapid film-based determination of antibiotic susceptibilities of Mycobacterium tuberculosis strains by using a luciferase reporter phage and the Bronx Box.

    PubMed

    Riska, P F; Su, Y; Bardarov, S; Freundlich, L; Sarkis, G; Hatfull, G; Carrière, C; Kumar, V; Chan, J; Jacobs, W R

    1999-04-01

    Detecting antibiotic resistance in Mycobacterium tuberculosis is becoming increasingly important with the global recognition of drug-resistant strains and their adverse impact on clinical outcomes. Current methods of susceptibility testing are either time-consuming or costly; rapid, reliable, simple, and inexpensive methods would be highly desirable, especially in the developing world where most tuberculosis is found. The luciferase reporter phage is a unique reagent well-suited for this purpose: upon infection with viable mycobacteria, it produces quantifiable light which is not observed in mycobacterial cells treated with active antimicrobials. In this report, we describe a modification of our original assay, which allows detection of the emitted light with a Polaroid film box designated the Bronx Box. The technique has been applied to 25 M. tuberculosis reference and clinical strains, and criteria are presented which allow rapid and simple discrimination among strains susceptible or resistant to isoniazid and rifampin, the major antituberculosis agents. PMID:10074539

  17. Antimicrobial susceptibility of Bacillus anthracis strains from Hungary.

    PubMed

    Kreizinger, Zsuzsa; Sulyok, Kinga Mária; Makrai, László; Rónai, Zsuzsanna; Fodor, László; Jánosi, Szilárd; Gyuranecz, Miklós

    2016-06-01

    The susceptibility of 29 Bacillus anthracis strains, collected in Hungary between 1933 and 2014, was tested to 10 antibiotics with commercially available minimum inhibitory concentration (MIC) test strips. All strains were susceptible to amoxicillin, ciprofloxacin, clindamycin, doxycycline, gentamicin, penicillin, rifampicin, and vancomycin. Intermediate susceptibility to erythromycin and cefotaxime was detected in 17.2% (5/29) and 58.6% (17/29) of the strains, respectively. Correlations were not observed between the isolation date, location, host species, genotype, and antibiotic susceptibility profile of strains. PMID:27342086

  18. Comparison of susceptibility and transcription profile of the new antifungal hassallidin A with caspofungin

    SciTech Connect

    Neuhof, Torsten . E-mail: t.neuhof@gmx.de; Seibold, Michael; Thewes, Sascha; Laue, Michael; Han, Chang-Ok; Hube, Bernhard; Doehren, Hans von

    2006-10-20

    This is First report on the antifungal effects of the new glycolipopeptide hassallidin A. Due to related molecular structure moieties between hassallidin A and the established antifungal drug caspofungin we assumed parallels in the effects on cell viability. Therefore we compared hassallidin A with caspofungin by antifungal susceptibility testing and by analysing the genome-wide transcriptional profile of Candida albicans. Furthermore, we examined modifications in ultracellular structure due to hassallidin A treatment by electron microscopy. Hassallidin A was found to be fungicidal against all tested Candida species and Cryptococcus neoformans isolates. MICs ranged from 4 to 8 {mu}g/ml, independently from the species. Electron microscopy revealed noticeable ultrastructural changes in C. albicans cells exposed to hassallidin A. Comparing the transcriptional profile of C. albicans cells treated with hassallidin A to that of cells exposed to caspofungin, only 20 genes were found to be similarly up- or down-regulated in both assays, while 227 genes were up- or down-regulated induced by hassallidin A specifically. Genes up-regulated in cells exposed to hassallidin A included metabolic and mitotic genes, while genes involved in DNA repair, vesicle docking, and membrane fusion were down-regulated. In summary, our data suggest that, although hassallidin A and caspofungin have similar structures, however, the effects on susceptibility and transcriptional response to yeasts seem to be different.

  19. First description of Candida nivariensis in Brazil: antifungal susceptibility profile and potential virulence attributes.

    PubMed

    Figueiredo-Carvalho, Maria Helena Galdino; Ramos, Livia de Souza; Barbedo, Leonardo Silva; Chaves, Alessandra Leal da Silva; Muramoto, Ilda Akemi; Santos, André Luis Souza dos; Almeida-Paes, Rodrigo; Zancopé-Oliveira, Rosely Maria

    2016-01-01

    This study evaluated the antifungal susceptibility profile and the production of potential virulence attributes in a clinical strain of Candida nivariensis for the first time in Brazil, as identified by sequencing the internal transcribed spacer (ITS)1-5.8S-ITS2 region and D1/D2 domains of the 28S of the rDNA. For comparative purposes, tests were also performed with reference strains. All strains presented low planktonic minimal inhibitory concentrations (PMICs) to amphotericin B (AMB), caspofungin (CAS), and voriconazole. However, our strain showed elevated planktonic MICs to posaconazole (POS) and itraconazole, in addition to fluconazole resistance. Adherence to inert surfaces was conducted onto glass and polystyrene. The biofilm formation and antifungal susceptibility on biofilm-growing cells were evaluated by crystal violet staining and a XTT reduction assay. All fungal strains were able to bind both tested surfaces and form biofilm, with a binding preference to polystyrene (p < 0.001). AMB promoted significant reductions (≈50%) in biofilm production by our C. nivariensis strain using both methodologies. This reduction was also observed for CAS and POS, but only in the XTT assay. All strains were excellent protease producers and moderate phytase producers, but lipases were not detected. This study reinforces the pathogenic potential of C. nivariensis and its possible resistance profile to the azolic drugs generally used for candidiasis management. PMID:26814644

  20. First description of Candida nivariensis in Brazil: antifungal susceptibility profile and potential virulence attributes

    PubMed Central

    Figueiredo-Carvalho, Maria Helena Galdino; Ramos, Livia de Souza; Barbedo, Leonardo Silva; Chaves, Alessandra Leal da Silva; Muramoto, Ilda Akemi; dos Santos, André Luis Souza; Almeida-Paes, Rodrigo; Zancopé-Oliveira, Rosely Maria

    2016-01-01

    This study evaluated the antifungal susceptibility profile and the production of potential virulence attributes in a clinical strain of Candida nivariensis for the first time in Brazil, as identified by sequencing the internal transcribed spacer (ITS)1-5.8S-ITS2 region and D1/D2 domains of the 28S of the rDNA. For comparative purposes, tests were also performed with reference strains. All strains presented low planktonic minimal inhibitory concentrations (PMICs) to amphotericin B (AMB), caspofungin (CAS), and voriconazole. However, our strain showed elevated planktonic MICs to posaconazole (POS) and itraconazole, in addition to fluconazole resistance. Adherence to inert surfaces was conducted onto glass and polystyrene. The biofilm formation and antifungal susceptibility on biofilm-growing cells were evaluated by crystal violet staining and a XTT reduction assay. All fungal strains were able to bind both tested surfaces and form biofilm, with a binding preference to polystyrene (p < 0.001). AMB promoted significant reductions (≈50%) in biofilm production by our C. nivariensis strain using both methodologies. This reduction was also observed for CAS and POS, but only in the XTT assay. All strains were excellent protease producers and moderate phytase producers, but lipases were not detected. This study reinforces the pathogenic potential of C. nivariensis and its possible resistance profile to the azolic drugs generally used for candidiasis management. PMID:26814644

  1. Phenotypic, antimicrobial susceptibility profile and virulence factors of Klebsiella pneumoniae isolated from buffalo and cow mastitic milk

    PubMed Central

    Osman, Kamelia M; Hassan, Hany M; Orabi, Ahmed; Abdelhafez, Ahmed S T

    2014-01-01

    Studies on the prevalence and virulence genes of Klebsiella mastitis pathogens in a buffalo population are undocumented. Also, the association of rmpA kfu, uge, magA, Aerobactin, K1 and K2 virulent factors with K. pneumoniae buffalo, and cow mastitis is unreported. The virulence of K. pneumoniae was evaluated through both phenotypic and molecular assays. In vivo virulence was assessed by the Vero cell cytotoxicity, suckling mouse assay and mice lethality test. Antimicrobial susceptibility was tested by disk diffusion method. The 45 K. pneumoniae isolates from buffalo (n = 10/232) and cow (n = 35/293) milk were isolated (45/525; 8.6%) and screened via PCR for seven virulence genes encoding uridine diphosphate galactose 4 epimerase encoding gene responsible for capsule and smooth lipopolysaccharide synthesis (uge), siderophores (kfu and aerobactin), protectines or invasins (rmpA and magA), and the capsule and hypermucoviscosity (K1 and K2). The most common virulence genes were rmpA, kfu, uge, and magA (77.8% each). Aerobactin and K1 genes were found at medium rates of 66.7% each and K2 (55.6%). The Vero cell cytotoxicity and LD (50) in mice were found in 100% of isolates. A multidrug resistance pattern was observed for 40% of the antimicrobials. The distribution of virulence profiles indicate a role of rmpA, kfu, uge, magA, Aerobactin, and K1 and K2 in pathogenicity of K. pneumoniae in udder infections and invasiveness, and constitutes a threat for vulnerable animals, even more if they are in combination with antibiotic resistance. PMID:24915048

  2. Evaluation of the PREVI® Isola automated seeder system compared to reference manual inoculation for antibiotic susceptibility testing by the disk diffusion method.

    PubMed

    Le Page, S; van Belkum, A; Fulchiron, C; Huguet, R; Raoult, D; Rolain, J-M

    2015-09-01

    The disk diffusion (DD) method remains the most popular manual technique for antibiotic susceptibility testing (AST) in clinical microbiology laboratories. This is because of its simplicity, reproducibility, and limited cost compared to (automated) microdilution systems, which are usually less sensitive at detecting certain important mechanisms of resistance. Here, we evaluate the PREVI® Isola automated seeder system using a new protocol for spreading bacterial suspensions (eight deposits of calibrated inocula of bacteria, followed by two rounds of rotation) in comparison with manual DD reference testing on a large series of clinical and reference strains. The average time required for seeding one agar plate for DD with this new protocol was 51 s per plate, i.e., 70 agar plates/h. Reproducibility and repeatability was assessed on three reference and three randomly chosen clinical strains, as usually requested by the European Committee on Antimicrobial Susceptibility Testing (EUCAST), and was excellent compared to the manual method. The standard deviations of zones of growth inhibition showed no statistical discrimination. The correlation between the two methods, assessed using 294 clinical isolates and a panel of six antibiotics (n = 3,528 zones of growth inhibition measured), was excellent, with a correlation coefficient of 0.977. The new PREVI® Isola protocol adapted for DD had a sensitivity of 99 % and a specificity of 100 % compared to the manual technique for interpreting DD as recommended by the EUCAST. PMID:26092031

  3. Antibiotic susceptibility pattern and identification of extended spectrum β-lactamases (ESBLs) in clinical isolates of Klebsiella pneumoniae from Shiraz, Iran

    PubMed Central

    Mansury, Davood; Motamedifar, Mohammad; Sarvari, Jamal; Shirazi, Babak; Khaledi, Azad

    2016-01-01

    Background and Objectives: Klebsiella pneumoniae, one of the important causes of nosocomial infections, is the most common extended spectrum β-lactamases (ESBLs) producing organism. ESBLs are defined as the enzymes capable of hydrolyzing oxyimino-cephalosporins, monobactams and carbapenems. The aims of this study were to identify ESBL-producing K. pneumoniae isolates and detect their antibiotic susceptibility pattern. Materials and Methods: This cross-sectional study was conducted from December 2012 to May 2013 in teaching hospitals in Shiraz. Clinical specimens from the urine, sputum, wound, blood, throat, and body fluids were isolated and identified as K. pneumoniae. Antibacterial susceptibility testing was performed for 14 antibiotics using disk diffusion method according to CLSI guidelines. Isolates showing resistant to at least one of the β-lactam antibiotics were then evaluated for production of β-lactamase enzymes using E-test ESBL and combined disk Method. Also, MICs for ceftazidime and imipenem were determined using E-test. The presence of the blaSHV, blaTEM, blaPER and blaCTX-M genes was assessed by PCR. Results: Of 144 K. pneumoniae isolates from different specimens, 38 (26.3 %) was identified as ESBL producer by phenotypic confirmatory test. All ESBL producing isolates were susceptible to imipenem and meropenem and resistant to aztreonam. The highest rate of resistance belonged to amoxicillin (100%), cefotaxime (50%) and gentamicin (42.3%) and the lowest rates were seen for meropenem (11.8%), imipenem and amikacin (both 15.9%). Sixty-two isolates had MICs≥ 4 μg/mL for ceftazidime, of which 38 were positive for ESBLs in phenotypic confirmatory tests (PCT). The prevalence of blaSHV, blaCTX-M, and blaTEM genes among these isolates were 22.2%, 19% and 16%. blaPER was not detected in the studied isolates. Conclusions: Due to the relatively high prevalence of ESBLs-producing K. pneumoniae isolates in the studied population, it seems that screening of

  4. Multiple Genetic Analysis System-Based Antibiotic Susceptibility Testing in Helicobacter pylori and High Eradication Rate With Phenotypic Resistance-Guided Quadruple Therapy.

    PubMed

    Dong, Fangyuan; Ji, Danian; Huang, Renxiang; Zhang, Fan; Huang, Yiqin; Xiang, Ping; Kong, Mimi; Nan, Li; Zeng, Xianping; Wu, Yong; Bao, Zhijun

    2015-11-01

    Antibiotics resistance in Helicobacter pylori (H. pylori) is the major factor for eradication failure. Molecular tests including fluorescence in situ hybridization, PCR-restriction fragment length polymorphism, and dual priming oligonucleotide-PCR (DPO-PCR) play critical roles in the detection of antibiotic susceptibility; however, limited knowledge is known about application of multiple genetic analysis system (MGAS) in the area of H. pylori identification and antibiotics resistance detection.The aim of this study is to determine the antibiotics resistance using different molecular tests and evaluate the treatment outcomes of E-test-based genotypic resistance.A total of 297 patients with dyspepsia complaint were recruited for gastroscopies. Ninety patients with H. pylori culture positive were randomly divided into 2 groups (test group and control group). E-test, general PCR, and MGAS assay were performed in test group. Patients in control group were treated with empirical therapy (rabeprazole + bismuth potassium citrate + amoxicillin [AMX] + clarithromycin [CLR]), whereas patients in test group received quadruple therapy based on E-test results twice daily for 14 consecutive days. The eradication effect of H. pylori was confirmed by C-urea breath test after at least 4 weeks when treatment was finished.Rapid urease test showed 46.5% (128/297) patients with H. pylori infection, whereas 30.3% (90/297) patients were H. pylori culture positive. E-test showed that H. pylori primary resistance rate to CLR, AMX, metronidazole, tetracycline, and levofloxacin (LVX) was 40.0% (18/45), 4.4% (2/45), 53.3% (24/45), 0% (0/45), and 55.6% (25/45), respectively. In addition, there are many multidrug resistant (MDR) phenotypes, and the MDR strains have higher minimum inhibitory concentration than their single-drug resistant counterparts. Considering E-test as the reference test, the sensitivities of general PCR and MGAS in detecting CLR resistance were 83.3% (15/18) and 94.4% (17

  5. In vitro susceptibility of e.faecalis and c.albicans isolates from apical periodontitis to common antimicrobial agents, antibiotics and antifungal medicaments

    PubMed Central

    Yoldas, Oguz; Yilmaz, Sehnaz; Akcimen, Beril; Seydaoglu, Gulsah; Kipalev, Arzu; Koksal, Fatih

    2012-01-01

    The aim of this study was to evaluate in vitro antimicrobial activity of 4 antibiotic agents (for E.faecalis) and 4 antifungal agents (for C.albicans) by agar dilution method. Additionally, modified strip diffusion method was used for detection of in vitro antimicrobial activities of 5% NaOCl, 2.5% NaOCl, 17% EDTA and 2% CHX and agar diffusion method for detection of in vitro susceptibilities of three intracanal medicaments for 18 E.faecalis and 18 C.albicans isolates from primary and secondary root canal infection. Isolates were recovered from 231 endodontic samples of patients, with the need of root canal treatment and retreatment. All tested E.faecalis isolates showed resistance to antibiotics. For irrigation solutions, 2% CHX was more effective in eliminating E.faecalis but 5% NaOCl showed larger inhibition zone than 2.5% NaOCl, 17% EDTA and 2% CHX. For intracanal medication, Ca(OH)2-CHX worked efficiently in killing E.faecalis isolates compared to Ca(OH)2-Steril saline solution, Ca(OH)2-Glycerin. For C.albicans, 18 isolates were susceptible to amphotericin B, nistatin, fluconazole but showed resistance to ketoconazole. 5% NaOCl was more effective in eliminating and produced larger inhibition zone compared to 2.5% NaOCl, 17% EDTA and 2% CHX. Ca(OH)2-Glycerin intracanal medication was better in eliminating C.albicans isolates and produced larger inhibition zone compared to other Ca(OH)2 medicaments. Key words:E.faecalis, C.albicans, antimicrobial, antibiotic, antifungal. PMID:24558517

  6. Antibiotic Susceptibility Patterns and Molecular Epidemiology of Metallo-β-Lactamase Producing Pseudomonas Aeruginosa Strains Isolated From Burn Patients

    PubMed Central

    Japoni, Aziz; Anvarinejad, Mojtaba; Farshad, Shohreh; Giammanco, Giovanni M; Rafaatpour, Noroddin; Alipour, Ebrahim

    2014-01-01

    Background: Failure in the treatment of burn patients infected with Pseudomonas aeruginosa could happen as a result of the acquisition of antibiotic resistance, including carbapenems. Objectives: The aim of the present study was to investigate the phenotypic and genotypic characteristics of the Pseudomonas aeruginosa strains, isolated from burn patients. Patients and Methods: During a 12 month period, in this cross-sectional study, two hundred seventy strains of Pseudomonas aeruginosa were isolated from the burn patients in Ghotbeddin Burn Hospital, Shiraz, Iran. Screening for the carbapenem resistance in the isolates was carried out by the E test method. Sensitivity patterns of metallo-β-lactamase (MβLs) producing strains of pseudomonas to eleven antibiotics were determined by the mentioned method. The epidemiological associations of these strains were determined by Pulsed-field gel electrophoresis (PFGE). Results: Of the 270 strains, 60 (22.2%) were resistant to imipenem and meropenem, classified as MβLs producing. MβLs producing strains of pseudomonas were completely resistant to five tested antibiotics while their sensitivities to the three most effective antibiotics including ceftazidime, amikacin and ciprofloxacin were 23.4%, 6.7 % and 1.7%, respectively. In PFGE, 37 patterns from the genome of Pseudomonas aeruginosa were observed. Majority of the strains (43; 71.6%) exhibited more than 80% similarity, based on the drawn dendrogram. Conclusions: According to the results, none of the tested antibiotics is safe to prescribe. As PFGE revealed, a limited number of Pseudomonas aeruginosa types are predominant in the hospitals which infect the burn patients. PMID:25031843

  7. Crystal structures of penicillin-binding protein 2 from penicillin-susceptible and -resistant strains of Neisseria gonorrhoeae reveal an unexpectedly subtle mechanism for antibiotic resistance.

    PubMed

    Powell, Ailsa J; Tomberg, Joshua; Deacon, Ashley M; Nicholas, Robert A; Davies, Christopher

    2009-01-01

    Penicillin-binding protein 2 (PBP2) from N. gonorrhoeae is the major molecular target for beta-lactam antibiotics used to treat gonococcal infections. PBP2 from penicillin-resistant strains of N. gonorrhoeae harbors an aspartate insertion after position 345 (Asp-345a) and 4-8 additional mutations, but how these alter the architecture of the protein is unknown. We have determined the crystal structure of PBP2 derived from the penicillin-susceptible strain FA19, which shows that the likely effect of Asp-345a is to alter a hydrogen-bonding network involving Asp-346 and the SXN triad at the active site. We have also solved the crystal structure of PBP2 derived from the penicillin-resistant strain FA6140 that contains four mutations near the C terminus of the protein. Although these mutations lower the second order rate of acylation for penicillin by 5-fold relative to wild type, comparison of the two structures shows only minor structural differences, with the positions of the conserved residues in the active site essentially the same in both. Kinetic analyses indicate that two mutations, P551S and F504L, are mainly responsible for the decrease in acylation rate. Melting curves show that the four mutations lower the thermal stability of the enzyme. Overall, these data suggest that the molecular mechanism underlying antibiotic resistance contributed by the four mutations is subtle and involves a small but measurable disordering of residues in the active site region that either restricts the binding of antibiotic or impedes conformational changes that are required for acylation by beta-lactam antibiotics. PMID:18986991

  8. Crystal Structures of Penicillin-Binding Protein 2 From Penicillin-Susceptible And -Resistant Strains of Neisseria Gonorrhoeae Reveal An Unexpectedly Subtle Mechanism for Antibiotic Resistance

    SciTech Connect

    Powell, A.J.; Tomberg, J.; Deacon, A.M.; Nicholas, R.A.; Davies, C.

    2009-05-21

    Penicillin-binding protein 2 (PBP2) from N. gonorrhoeae is the major molecular target for {beta}-lactam antibiotics used to treat gonococcal infections. PBP2 from penicillin-resistant strains of N. gonorrhoeae harbors an aspartate insertion after position 345 (Asp-345a) and 4-8 additional mutations, but how these alter the architecture of the protein is unknown. We have determined the crystal structure of PBP2 derived from the penicillin-susceptible strain FA19, which shows that the likely effect of Asp-345a is to alter a hydrogen-bonding network involving Asp-346 and the SXN triad at the active site. We have also solved the crystal structure of PBP2 derived from the penicillin-resistant strain FA6140 that contains four mutations near the C terminus of the protein. Although these mutations lower the second order rate of acylation for penicillin by 5-fold relative to wild type, comparison of the two structures shows only minor structural differences, with the positions of the conserved residues in the active site essentially the same in both. Kinetic analyses indicate that two mutations, P551S and F504L, are mainly responsible for the decrease in acylation rate. Melting curves show that the four mutations lower the thermal stability of the enzyme. Overall, these data suggest that the molecular mechanism underlying antibiotic resistance contributed by the four mutations is subtle and involves a small but measurable disordering of residues in the active site region that either restricts the binding of antibiotic or impedes conformational changes that are required for acylation by {beta}-lactam antibiotics.

  9. Antimicrobial activity, antibiotic susceptibility and virulence factors of Lactic Acid Bacteria of aquatic origin intended for use as probiotics in aquaculture

    PubMed Central

    2013-01-01

    Background The microorganisms intended for use as probiotics in aquaculture should exert antimicrobial activity and be regarded as safe not only for the aquatic hosts but also for their surrounding environments and humans. The objective of this work was to investigate the antimicrobial/bacteriocin activity against fish pathogens, the antibiotic susceptibility, and the prevalence of virulence factors and detrimental enzymatic activities in 99 Lactic Acid Bacteria (LAB) (59 enterococci and 40 non-enterococci) isolated from aquatic animals regarded as human food. Results These LAB displayed a broad antimicrobial/bacteriocin activity against the main Gram-positive and Gram-negative fish pathogens. However, particular safety concerns based on antibiotic resistance and virulence factors were identified in the genus Enterococcus (86%) (Enterococcus faecalis, 100%; E. faecium, 79%). Antibiotic resistance was also found in the genera Weissella (60%), Pediococcus (44%), Lactobacillus (33%), but not in leuconostocs and lactococci. Antibiotic resistance genes were found in 7.5% of the non-enterococci, including the genera Pediococcus (12.5%) and Weissella (6.7%). One strain of both Pediococcus pentosaceus and Weissella cibaria carried the erythromycin resistance gene mef(A/E), and another two P. pentosaceus strains harboured lnu(A) conferring resistance to lincosamides. Gelatinase activity was found in E. faecalis and E. faecium (71 and 11%, respectively), while a low number of E. faecalis (5%) and none E. faecium exerted hemolytic activity. None enterococci and non-enterococci showed bile deconjugation and mucin degradation abilities, or other detrimental enzymatic activities. Conclusions To our knowledge, this is the first description of mef(A/E) in the genera Pediococcus and Weissella, and lnu(A) in the genus Pediococcus. The in vitro subtractive screening presented in this work constitutes a valuable strategy for the large-scale preliminary selection of putatively safe LAB

  10. Genotyping as a tool for antibiotic resistance surveillance of Neisseria gonorrhoeae in New Caledonia: evidence of a novel genotype associated with reduced penicillin susceptibility.

    PubMed

    Vernel-Pauillac, Frédérique; Nandi, Sobhan; Nicholas, Robert A; Goarant, Cyrille

    2008-09-01

    Antibiotic resistance in Neisseria gonorrhoeae continues to be a major concern in public health. Resistance of N. gonorrhoeae bacteria to penicillin G is widespread in most developed countries, which has necessitated a change to newer drugs for treatment of gonococcal infections. Recent reports indicate that resistance to these newer drugs is increasing, highlighting the need for accurate therapeutic recommendations. In some countries or communities, however, N. gonorrhoeae isolates are still susceptible to penicillin, so the use of this antibiotic for single-dose treatments of medically under-resourced patients is beneficial. In order to evaluate the adequacy and sustainability of this treatment approach, we explored the presence and prevalence of chromosomally mediated resistance determinants in N. gonorrhoeae isolates collected from 2005 to 2007 in New Caledonia. We developed two new real-time PCR assays targeting the penB and mtrR determinants, to be used together with a previously described duplex assay targeting the penA and ponA determinants. The results of this study provided evidence that neither the most-common mtrR determinants nor the most-resistance-associated penB alleles are currently circulating in New Caledonia, suggesting that penicillin should still be considered a valuable treatment strategy. Additionally, using our genotyping assay, we observed an unexpected penB genotype at a relatively high frequency that was associated with a decreased susceptibility to penicillin (average MIC, 0.15 mug/ml). Sequencing revealed that this genotype corresponded to an A102S mutation in the penB gene. The molecular tools developed in this study can be used successfully for prospective epidemiological monitoring and surveillance of penicillin susceptibility. PMID:18591264

  11. Profiles of epigenetic histone post-translational modifications at type 1 diabetes susceptible genes.

    PubMed

    Miao, Feng; Chen, Zhuo; Zhang, Lingxiao; Liu, Zheng; Wu, Xiwei; Yuan, Yate-Ching; Natarajan, Rama

    2012-05-11

    Both genetic and environmental factors are implicated in type 1 diabetes (T1D). Because environmental factors can trigger epigenetic changes, we hypothesized that variations in histone post-translational modifications (PTMs) at the promoter/enhancer regions of T1D susceptible genes may be associated with T1D. We therefore evaluated histone PTM variations at known T1D susceptible genes in blood cells from T1D patients versus healthy nondiabetic controls, and explored their connections to T1D. We used the chromatin immunoprecipitation-linked to microarray approach to profile key histone PTMs, including H3-lysine 4 trimethylation (H3K4me3), H3K27me3, H3K9me3, H3K9 acetylation (H3K9Ac), and H4K16Ac at genes within the T1D susceptible loci in lymphocytes, and H3K4me3, H3K9me2, H3K9Ac, and H4K16Ac at the insulin-dependent diabetes mellitus 1 region in monocytes of T1D patients and healthy controls separately. We screened for potential variations in histone PTMs using computational methods to compare datasets from T1D and controls. Interestingly, we observed marked variations in H3K9Ac levels at the upstream regions of HLA-DRB1 and HLA-DQB1 within the insulin-dependent diabetes mellitus 1 locus in T1D monocytes relative to controls. Additional experiments with THP-1 monocytes demonstrated increased expression of HLA-DRB1 and HLA-DQB1 in response to interferon-γ and TNF-α treatment that were accompanied by changes in H3K9Ac at the same promoter regions as that seen in the patient monocytes. These results suggest that the H3K9Ac status of HLA-DRB1 and HLA-DQB1, two genes highly associated with T1D, may be relevant to their regulation and transcriptional response toward external stimuli. Thus, the promoter/enhancer architecture and chromatin status of key susceptible loci could be important determinants in their functional association to T1D susceptibility. PMID:22431725

  12. Differences in Rhodococcus equi Infections Based on Immune Status and Antibiotic Susceptibility of Clinical Isolates in a Case Series of 12 Patients and Cases in the Literature

    PubMed Central

    Suzuki, Yasuhiro; Ribes, Julie A.; Thornton, Alice

    2016-01-01

    Rhodococcus equi is an unusual zoonotic pathogen that can cause life-threatening diseases in susceptible hosts. Twelve patients with R. equi infection in Kentucky were compared to 137 cases reported in the literature. Although lungs were the primary sites of infection in immunocompromised patients, extrapulmonary involvement only was more common in immunocompetent patients (P < 0.0001). Mortality in R. equi-infected HIV patients was lower in the HAART era (8%) than in pre-HAART era (56%) (P < 0.0001), suggesting that HAART improves prognosis in these patients. Most (85–100%) of clinical isolates were susceptible to vancomycin, clarithromycin, rifampin, aminoglycosides, ciprofloxacin, and imipenem. Interestingly, there was a marked difference in susceptibility of the isolates to cotrimoxazole between Europe (35/76) and the US (15/15) (P < 0.0001). Empiric treatment of R. equi infection should include a combination of two antibiotics, preferably selected from vancomycin, imipenem, clarithromycin/azithromycin, ciprofloxacin, rifampin, or cotrimoxazole. Local antibiograms should be checked prior to using cotrimoxazole due to developing resistance.

  13. Iron-Chelating Activity of Tetracyclines and Its Impact on the Susceptibility of Actinobacillus actinomycetemcomitans to These Antibiotics

    PubMed Central

    Grenier, Daniel; Huot, Marie-Pierre; Mayrand, Denis

    2000-01-01

    Three tetracyclines (tetracycline, doxycycline, and minocycline) were found to possess iron-chelating activity in a colorimetric siderophore assay. Determination of MICs indicated that the activity of doxycycline against the periodontopathogen Actinobacillus actinomycetemcomitans was only slightly influenced by the presence of an excess of iron that likely saturates the antibiotic. On the other hand, the MICs of doxycycline and minocycline were significantly lower for A. actinomycetemcomitans cultivated under iron-poor conditions than under iron-rich conditions. PMID:10681353

  14. A comparison of antimicrobial susceptibility profile of urinary pathogens for the years, 1999 and 2003.

    PubMed

    Orrett, F A; Davis, G K

    2006-03-01

    Urinary tract infection is a common condition worldwide; responsible for significant morbidity in both hospitalized and community patients. The laboratory records, for microbial isolates of infected urine and their susceptibility profiles for the years 1999 and 2003 were retrospectively reviewed and compared. In 2003, there was a significant decline in recovery ofCitrobacter spp compared to 1999. Conversely, the proportion of K pneumoniae, E coli and Enterococci increased dramatically in 2003, in both practices. For Proteus vulgaris and Proteus mirabilis, rates of isolation were increased in 2003, in hospital practice and community practice, respectively. Significant changes in antimicrobial susceptibility were also evident. A greater proportion of isolates from both practices were resistant to ampicillin, amoxicillin-clavulanic acid, cefuroxime, ceftazidime and cotrimoxazole in 2003 when compared to 1999. With respect to E coli, there were significant increases in prevalence of resistance to cefuroxime and amoxicillin-clavulanic acid. The overall resistance rate for norfloxacin remained relatively low and was unchanged for E coli. Continued surveillance of uropathogen resistance trends is important and this information should be communicated to clinicians. The feasibility of using the fluoroquinolones as a first line of therapy in urinary tract infection should be considered. PMID:16921702

  15. Variability of antibiotic susceptibility and toxin production of Staphylococcus aureus strains isolated from skin, soft tissue, and bone related infections

    PubMed Central

    2013-01-01

    Background Staphylococcus aureus is an opportunistic commensal bacterium that mostly colonizes the skin and soft tissues. The pathogenicity of S. aureus is due to both its ability to resist antibiotics, and the production of toxins. Here, we characterize a group of genes responsible for toxin production and antibiotic resistance of S. aureus strains isolated from skin, soft tissue, and bone related infections. Results A total of 136 S. aureus strains were collected from five different types of infection: furuncles, pyomyositis, abscesses, Buruli ulcers, and osteomyelitis, from hospital admissions and out-patients in Benin. All strains were resistant to benzyl penicillin, while 25% were resistant to methicillin, and all showed sensitivity to vancomycin. Panton-Valentine leukocidin (PVL) was the most commonly produced virulence factor (70%), followed by staphylococcal enterotoxin B (44%). Exfoliative toxin B was produced by 1.3% of the strains, and was only found in isolates from Buruli ulcers. The tsst-1, sec, and seh genes were rarely detected (≤1%). Conclusions This study provides new insight into the prevalence of toxin and antibiotic resistance genes in S. aureus strains responsible for skin, soft tissue, and bone infections. Our results showed that PVL was strongly associated with pyomyositis and osteomyelitis, and that there is a high prevalence of PVL-MRSA skin infections in Benin. PMID:23924370

  16. Oncocin Onc72 is efficacious against antibiotic-susceptible Klebsiella pneumoniae ATCC 43816 in a murine thigh infection model.

    PubMed

    Knappe, Daniel; Adermann, Knut; Hoffmann, Ralf

    2015-11-01

    Oncocins and apidaecins are short proline-rich antimicrobial peptides (PrAMPs) representing novel antibiotic drug lead compounds that kill bacteria after internalization and inhibition of intracellular targets (e.g. 70S ribosome and DnaK). Oncocin Onc72 is highly active against Gram-negative bacteria in vitro and in vivo protecting mice in systemic infection models with Escherichia coli and KPC-producing Klebsiella pneumoniae. Here we studied its efficacy in a murine thigh infection model using meropenem as antibiotic comparator that had a 44-fold higher molar in vitro activity than Onc72. Male CD1 mice were rendered neutropenic using cyclophosphamide for four days before intramuscular infection with K. pneumoniae ATCC 43816. After 75 min oncocin Onc72 or the antibiotic comparator meropenem were administered subcutaneously with 100 mg (43 µmol) and 25 mg (65 µmol) per kg of body weight, respectively, six times every 75 min. Onc72 and meropenem administered subcutaneously reduced the thigh tissue burden of K. pneumoniae ATCC 43816 in neutropenic mice significantly by 4.14 and 4.65 a log10 cfu/g, respectively. The bacterial counts were ∼0.5 and ∼1 log10 below the pre-treatment burden, respectively, indicating bactericidal effects for both compounds. Thus, Onc72 was as efficacious as meropenem in vivo despite its much lower in vitro activity determined according to CLSI standard antimicrobial activity tests. PMID:25968331

  17. [Seven kinds of new SCCmec type in Methicillin-resistant Staphyloccus aureus and their susceptibility to the antibiotics].

    PubMed

    Ouyang, Fan-xian; Bu, Ping-feng; Huang, Hui-qin; Bao, Shi-xiang

    2007-04-01

    In order to explore the resistance and the staphylococcal chromosome cassette mec (SCCmec) types of Methicillin-resistant S. aureus (MRSA) in the area of Haikou, 686 strains of MRSA had been distinguished from 1174 strains of S. aureus using PBP2a testing. The resistance to the seven deputies of seven kinds antibiotics which in common use in clinic, including Oxacillin, Vancomycin, Doxycyclin, Amikacin, Erythromycin, Chloramphenicol, Ciprofloxacin, and SCCmec type of 58 strains had been tested using the K-B Agar diffuse, E-test and multiplex PCR strategy, and seven kinds of new SCCmec types were found in 17 strains. Their specialties of structure are: type-new3 possess four loci of A, F, H, M; New4 possess three loci of F, H, M; New5 possess three loci of D, B, M; New6 possess three loci of A, B, M; New7 possess four loci of H, E, C, M; New8 possess two loci of A, M; New9 possess three loci of A, C, M. All of them are different from the types reported. The strains carrying new SCC mec types are different from that carrying old SCC mec types in the epidemical distribution and resistance to the antibiotics: they were mostly isolated from the out-patients and have high level and wider range of resistance to antibiotics and deserve to pay more attention. PMID:17552220

  18. Effect of chlorination on antibiotic resistance profiles of sewage-related bacteria.

    PubMed Central

    Murray, G E; Tobin, R S; Junkins, B; Kushner, D J

    1984-01-01

    A total of 1,900 lactose-fermenting bacteria were isolated from raw sewage influent and chlorinated sewage effluent from a sewage treatment plant, as well as from chlorinated and neutralized dilute sewage, before and after a 24-h regrowth period in the laboratory. Of these isolates, 84% were resistant to one or more antibiotics. Chlorination of influent resulted in an increase in the proportion of bacteria resistant to ampicillin and cephalothin, the increase being most marked after regrowth occurred following chlorination. Of the other nine antibiotics tested, chlorination resulted in an increased proportion of bacteria resistant to some, but a decrease in the proportion resistant to the remainder. Multiple resistance was found for up to nine antibiotics, especially in regrowth populations. Identification of about 5% of the isolates showed that the highest proportion of Escherichia coli fell in untreated sewage. Some rare and potentially pathogenic species were isolated from chlorinated and regrowth samples, including Yersinia enterocolitica, Yersinia pestis, Pasteurella multocida, and Hafnia alvei. Our results indicate that chlorination, while initially lowering the total number of bacteria in sewage, may substantially increase the proportions of antibiotic-resistant, potentially pathogenic organisms. PMID:6476832

  19. Metagenomic Profiling of Antibiotic Resistance Genes and Mobile Genetic Elements in a Tannery Wastewater Treatment Plant

    PubMed Central

    Wang, Zhu; Zhang, Xu-Xiang; Huang, Kailong; Miao, Yu; Shi, Peng; Liu, Bo; Long, Chao; Li, Aimin

    2013-01-01

    Antibiotics are often used to prevent sickness and improve production in animal agriculture, and the residues in animal bodies may enter tannery wastewater during leather production. This study aimed to use Illumina high-throughput sequencing to investigate the occurrence, diversity and abundance of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in aerobic and anaerobic sludge of a full-scale tannery wastewater treatment plant (WWTP). Metagenomic analysis showed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria dominated in the WWTP, but the relative abundance of archaea in anaerobic sludge was higher than in aerobic sludge. Sequencing reads from aerobic and anaerobic sludge revealed differences in the abundance of functional genes between both microbial communities. Genes coding for antibiotic resistance were identified in both communities. BLAST analysis against Antibiotic Resistance Genes Database (ARDB) further revealed that aerobic and anaerobic sludge contained various ARGs with high abundance, among which sulfonamide resistance gene sul1 had the highest abundance, occupying over 20% of the total ARGs reads. Tetracycline resistance genes (tet) were highly rich in the anaerobic sludge, among which tet33 had the highest abundance, but was absent in aerobic sludge. Over 70 types of insertion sequences were detected in each sludge sample, and class 1 integrase genes were prevalent in the WWTP. The results highlighted prevalence of ARGs and MGEs in tannery WWTPs, which may deserve more public health concerns. PMID:24098424

  20. Epidemiology and antimicrobial susceptibility profiles of pathogens causing urinary tract infections in the Asia-Pacific region: Results from the Study for Monitoring Antimicrobial Resistance Trends (SMART), 2010-2013.

    PubMed

    Jean, Shio-Shin; Coombs, Geoffrey; Ling, Thomas; Balaji, V; Rodrigues, Camilla; Mikamo, Hiroshige; Kim, Min-Ja; Rajasekaram, Datin Ganeswrie; Mendoza, Myrna; Tan, Thean Yen; Kiratisin, Pattarachai; Ni, Yuxing; Weinman, Barry; Xu, Yingchun; Hsueh, Po-Ren

    2016-04-01

    A total of 9599 isolates of Gram-negative bacteria (GNB) causing urinary tract infections (UTIs) were collected from 60 centres in 13 countries in the Asia-Pacific region from 2010-2013. These isolates comprised Enterobacteriaceae species (mainly Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Klebsiella oxytoca, Enterobacter cloacae and Morganella morganii) and non-fermentative GNB species (predominantly Pseudomonas aeruginosa and Acinetobacter baumannii). In vitro susceptibilities were determined by the agar dilution method and susceptibility profiles were determined using the minimum inhibitory concentration (MIC) interpretive breakpoints recommended by the Clinical and Laboratory Standards Institute in 2015. Production of extended-spectrum β-lactamases (ESBLs) amongst E. coli, K. pneumoniae, P. mirabilis and K. oxytoca isolates was determined by the double-disk synergy test. China, Vietnam, India, Thailand and the Philippines had the highest rates of GNB species producing ESBLs and the highest rates of cephalosporin resistance. ESBL production and hospital-acquired infection (isolates obtained ≥48h after admission) significantly compromised the susceptibility of isolates of E. coli and K. pneumoniae to ciprofloxacin, levofloxacin and most β-lactams, with the exception of imipenem and ertapenem. However, >87% of ESBL-producing E. coli strains were susceptible to amikacin and piperacillin/tazobactam, indicating that these antibiotics might be appropriate alternatives for treating UTIs due to ESBL-producing E. coli. Fluoroquinolones were shown to be inappropriate as empirical therapy for UTIs. Antibiotic resistance is a serious problem in the Asia-Pacific region. Therefore, continuous monitoring of evolutionary trends in the susceptibility profiles of GNB causing UTIs in Asia is crucial. PMID:27005459

  1. Case Series of Imported Enteric Fever at a Referral Center in Tokyo, Japan: Antibiotic Susceptibility and Risk Factors for Relapse.

    PubMed

    Matono, Takashi; Kato, Yasuyuki; Morita, Masatomo; Izumiya, Hidemasa; Yamamoto, Kei; Kutsuna, Satoshi; Takeshita, Nozomi; Hayakawa, Kayoko; Mezaki, Kazuhisa; Kawamura, Maho; Konishi, Noriko; Mizuno, Yasutaka; Kanagawa, Shuzo; Ohmagari, Norio

    2016-07-01

    Owing to the increase in Salmonella strains with decreased fluoroquinolone susceptibility in the endemic areas, we have been treating enteric fever with intravenous ceftriaxone empirically since 2007. In this study, we reevaluated our treatment protocol. This retrospective cohort study was conducted at a single institute in Tokyo, Japan, between January 2006 and December 2013. Enteric fever was defined as isolation of Salmonella Typhi or Salmonella Paratyphi A, B, and C from the blood and/or stool of patients with fever. Of the 35 patients with imported enteric fever, 28 (80%) had returned from south Asia. Ciprofloxacin-susceptible strains were detected in only 12% of the cases. The isolates showed excellent susceptibility to ampicillin (91%), chloramphenicol (94%), ceftriaxone (97%), and azithromycin (97%). One case of Salmonella Paratyphi B was excluded, and of the remaining 34 patients, 56% were treated with ceftriaxone alone, 26% with ceftriaxone then fluoroquinolone, and 9% with levofloxacin alone. The overall relapse rate was 6.1%; however, among those receiving ceftriaxone monotherapy, the relapse rate was 11% (N = 2). The relapse group was characterized by longer times to treatment initiation (P = 0.035) and defervescence (> 7 days) after treatment initiation (P = 0.022). In such cases, we recommend that ceftriaxone treatment be continued for > 4 days after defervescence or be changed to fluoroquinolone if the strains are found to be susceptible to prevent relapse. Furthermore, ampicillin and chloramphenicol, which are no longer prescribed, may be reconsidered as treatment options in Asia. PMID:27162265

  2. [Evaluation of antibiotic susceptibilities and VISA-VRSA rates among MRSA strains isolated from hospitalized patients in intensive care units of hospitals in seven provinces of Turkey].

    PubMed

    Cesur, Salih; Irmak, Hasan; Simşek, Hüsniye; Cöplü, Nilay; Kılıç, Hasan; Arslan, Uğur; Bayramoğlu, Gülçin; Baysan, Betil Ozhak; Gülay, Zeynep; Hoşoğlu, Salih; Berktaş, Mustafa; Gencer, Serap; Demiröz, Ali Pekcan; Esen, Berrin; Karabiber, Nihal; Aydın, Faruk; Yalçın, Ata Nevzat

    2012-07-01

    The aim of this study was to determine whether vancomycin resistant Staphylococcus aureus (VRSA) and vancomycin intermediate susceptible S.aureus (VISA) strains were present among methicillin-resistant S.aureus (MRSA) strains isolated from patients hospitalised at intensive care units (ICU) of hospitals located at different regions of Turkey and to determine the minimum inhibitory concentration (MIC) values of teicoplanin, linezolid, tigecycline, quinupristin-dalfopristin and daptomycin, which are alternative drugs for the treatment of MRSA infections. A total of 260 MRSA clinical strains (isolated from 113 lower respiratory tract, 90 blood, 24 wound, 17 catheter, 13 nasal swabs, two urine and one CSF sample) were collected from nine health-care centers in eight provinces [Ankara (n= 52), Konya (n= 49), Antalya (n= 40), Istanbul (n= 7), Izmir (37), Diyarbakir (n= 15), Van (n= 12), Trabzon (n= 48)] selected as representatives of the seven different geographical regions of Turkey. Methicillin resistance was determined by cefoxitin disk diffusion in the hospitals where the strains were isolated and confirmed by oxacillin salt agar screening at the Refik Saydam National Public Health Agency. Screening for VISA and VRSA was conducted using the agar screening test and E-test. Susceptibility of the MRSA strains to other antibiotics was also determined by E-test method. None of the 260 MRSA strains were determined to be VRSA or VISA. All were susceptible to teicoplanin and linezolid, and susceptibility rates to daptomycin, tigecycline and quinupristin-dalfopristin were 99.6%, 96.9%, and 95%, respectively. Absence of VISA and VRSA among the MRSA strains surveyed currently seemed hopeful, however, continuous surveillance is necessary. In order to prevent the development of VISA and VRSA strains the use of linezolid, tigecycline, quinupristin-dalfopristin and daptomycin should be encouraged as alternative agents of treatment of MRSA infections. PMID:22951647

  3. Target Product Profile of a Molecular Drug-Susceptibility Test for Use in Microscopy Centers

    PubMed Central

    Denkinger, Claudia M.; Dolinger, David; Schito, Marco; Wells, William; Cobelens, Frank; Pai, Madhukar; Zignol, Matteo; Cirillo, Daniela Maria; Alland, David; Casenghi, Martina; Gallarda, Jim; Boehme, Catharina C.; Perkins, Mark D.

    2015-01-01

    Background. Current phenotypic testing for drug resistance in patients with tuberculosis is inadequate primarily with respect to turnaround time. Molecular tests hold the promise of an improved time to diagnosis. Methods. A target product profile for a molecular drug-susceptibility test (DST) was developed on the basis of a collaborative effort that included opinions gathered from researchers, clinicians, policy makers, and test developers on optimal clinical and operational characteristics in settings of intended use. In addition, the current diagnostic ecosystem and the diagnostic development landscape were mapped. Results. Molecular DSTs for detecting tuberculosis in microscopy centers should ideally evaluate for resistance to rifampin, fluoroquinolones, isoniazid, and pyrazinamide and enable the selection of the most appropriate treatment regimen. Performance characteristics of DSTs need to be optimized, but compromises can be made that depend on the trade-off between a false-positive result and a false-negative result. The operational requirements of a test will vary depending on the site of implementation. However, the most-important considerations pertain to quality control, maintenance and calibration, and the ability to export data. Conclusion. This target product profile defines the needs as perceived by the tuberculosis stakeholder community and attempts to provide a means of communication with test developers to ensure that fit-for-purpose DSTs are being developed. PMID:25765105

  4. [Non-fermentative gram-negative bacilli: their distribution to clinical materials and antibiotic susceptibility (author's transl)].

    PubMed

    Akalin, H E; Baykal, M

    1980-01-01

    A total of 7898 non-fermentative Gram-negative bacilli were isolated from various clinical materials. Pseudomonas (7526) was the most common among them. Alcaligenes faecalis (273), Acinetobacter sp. (93) and Flavobacterium (6) were the other non-fermentative Gram-negative bacilli. Most of them were found in urine and pus cultures, however they were also isolated from sputum, blood, and cerebrospinal fluid. Gentamicin was the most effective antibiotic in vitro. Fifty four per cent of Pseudomonas, 100% of Acinetobacter, and 70% of Alcaligenes faecalis were inhibited by tobramycin. PMID:7453583

  5. Incidence, microbiological profile of nosocomial infections, and their antibiotic resistance patterns in a high volume Cardiac Surgical Intensive Care Unit

    PubMed Central

    Sahu, Manoj Kumar; Siddharth, Bharat; Choudhury, Arin; Vishnubhatla, Sreenivas; Singh, Sarvesh Pal; Menon, Ramesh; Kapoor, Poonam Malhotra; Talwar, Sachin; Choudhary, Shiv; Airan, Balram

    2016-01-01

    Background: Nosocomial infections (NIs) in the postoperative period not only increase morbidity and mortality, but also impose a significant economic burden on the health care infrastructure. This retrospective study was undertaken to (a) evaluate the incidence, characteristics, risk factors and outcomes of NIs and (b) identify common microorganisms responsible for infection and their antibiotic resistance profile in our Cardiac Surgical Intensive Care Unit (CSICU). Patients and Methods: After ethics committee approval, the CSICU records of all patients who underwent cardiovascular surgery between January 2013 and December 2014 were reviewed retrospectively. The incidence of NI, distribution of NI sites, types of microorganisms and their antibiotic resistance, length of CSICU stay, and patient-outcome were determined. Results: Three hundred and nineteen of 6864 patients (4.6%) developed NI after cardiac surgery. Lower respiratory tract infections (LRTIs) accounted for most of the infections (44.2%) followed by surgical-site infection (SSI, 11.6%), bloodstream infection (BSI, 7.5%), urinary tract infection (UTI, 6.9%) and infections from combined sources (29.8%). Acinetobacter, Klebsiella, Escherichia coli, and Staphylococcus were the most frequent pathogens isolated in patients with LRTI, BSI, UTI, and SSI, respectively. The Gram-negative bacteria isolated from different sources were found to be highly resistant to commonly used antibiotics. Conclusion: The incidence of NI and sepsis-related mortality, in our CSICU, was 4.6% and 1.9%, respectively. Lower respiratory tract was the most common site of infection and Gram-negative bacilli, the most common pathogens after cardiac surgery. Antibiotic resistance was maximum with Acinetobacter spp. PMID:27052070

  6. Antibiotic resistance in Staphylococcus aureus strains isolated from cows with mastitis in eastern Poland and analysis of susceptibility of resistant strains to alternative nonantibiotic agents: lysostaphin, nisin and polymyxin B.

    PubMed

    Szweda, Piotr; Schielmann, Marta; Frankowska, Aneta; Kot, Barbara; Zalewska, Magdalena

    2014-03-01

    The aim of this study was to analyze the resistance of Staphylococcus aureus isolates from bovine mastitis in the eastern part of Poland to a set of 20 antibiotics and three alternative agents: lysostaphin, nisin and polymyxin B. Eighty-six out of 123 examined isolates were susceptible to all 20 tested antibiotics (70%). The highest percentage of resistance was observed in the case of β-lactam antibiotics: amoxicillin (n=22, 17.9%), ampicillin (n=28, 22.8%), penicillin (n=29, 23.6%) and streptomycin (n=13; 10.6%). Twenty-five of the penicillin-resistant strains were found to carry the blaZ gene coding for β-lactamases. Two strains were found to be mecA positive and a few strains were classified as multidrug resistant (MDR), one of them was simultaneously resistant to six antibiotics. All strains, resistant to at least one antibiotic (n=37) and two control strains, were susceptible to lysostaphin with MIC values of 0.008-0.5 µg/ml (susceptibility breakpoint 32 µg/ml). Twenty-one (54%) isolates were susceptible to nisin. The MIC value of this agent for 17 (44%) strains was 51.2 µg/ml and was not much higher than the susceptibility breakpoint value (32 µg/ml). Polymyxin B was able to inhibit the growth of the strains only at a high concentration (32-128 µg/ml). The presented results confirmed the observed worldwide problem of spreading antibiotic resistance among staphylococci isolated from bovine mastitis; on the other hand, we have indicated a high level of bactericidal activity of nisin and especially lysostaphin. PMID:24212507

  7. Antibiotic Resistance in Staphylococcus aureus Strains Isolated from Cows with Mastitis in Eastern Poland and Analysis of Susceptibility of Resistant Strains to Alternative Nonantibiotic Agents: Lysostaphin, Nisin and Polymyxin B

    PubMed Central

    SZWEDA, Piotr; SCHIELMANN, Marta; FRANKOWSKA, Aneta; KOT, Barbara; ZALEWSKA, Magdalena

    2013-01-01

    ABSTRACT The aim of this study was to analyze the resistance of Staphylococcus aureus isolates from bovine mastitis in the eastern part of Poland to a set of 20 antibiotics and three alternative agents: lysostaphin, nisin and polymyxin B. Eighty-six out of 123 examined isolates were susceptible to all 20 tested antibiotics (70%). The highest percentage of resistance was observed in the case of β-lactam antibiotics: amoxicillin (n=22, 17.9%), ampicillin (n=28, 22.8%), penicillin (n=29, 23.6%) and streptomycin (n=13; 10.6%). Twenty-five of the penicillin-resistant strains were found to carry the blaZ gene coding for β-lactamases. Two strains were found to be mecA positive and a few strains were classified as multidrug resistant (MDR), one of them was simultaneously resistant to six antibiotics. All strains, resistant to at least one antibiotic (n=37) and two control strains, were susceptible to lysostaphin with MIC values of 0.008–0.5 µg/ml (susceptibility breakpoint 32 µg/ml). Twenty-one (54%) isolates were susceptible to nisin. The MIC value of this agent for 17 (44%) strains was 51.2 µg/ml and was not much higher than the susceptibility breakpoint value (32 µg/ml). Polymyxin B was able to inhibit the growth of the strains only at a high concentration (32–128 µg/ml). The presented results confirmed the observed worldwide problem of spreading antibiotic resistance among staphylococci isolated from bovine mastitis; on the other hand, we have indicated a high level of bactericidal activity of nisin and especially lysostaphin. PMID:24212507

  8. Preliminary results of a new antibiotic susceptibility test against biofilm installation in device-associated infections: the Antibiofilmogram®.

    PubMed

    Tasse, Jason; Croisier, Delphine; Badel-Berchoux, Stéphanie; Chavanet, Pascal; Bernardi, Thierry; Provot, Christian; Laurent, Frédéric

    2016-08-01

    Biofilms are complex communities of microorganisms embedded in an extracellular matrix and adherent to a surface. The development was described as a four-stage process leading to the formation of a mature biofilm which was resistant to immune system and antibiotic actions. In bone and joint infections (BJIs), the formation of biofilms is a leading cause of treatment failure. Here we study the capacity of 11 antibiotics commonly used in the treatment of BJIs to inhibit the biofilm formation on 29 clinical Staphylococcus aureus isolates by a new test called Antibiofilmogram(®) The minimal inhibitory concentration (MIC) and biofilm MIC (bMIC) were determined in vitro and showed similar values for clindamycin, fusidic acid, linezolid and rifampin. Reversely, daptomycin, fosfomycin, gentamicin and ofloxacin showed a bMIC distribution different from MIC with bMIC above breakpoint. Finally, cloxacillin, teicoplanin and vancomycin revealed an intermediate bMIC distribution with a strain-dependent pattern. A murine in vivo model of catheter-associated S. aureus infection was made and showed a significant reduction, but not total prevention, of catheter colonization with cloxacillin at bMIC, and no or limited reduction with cloxacillin at MIC. Antibiofilmogram(®) could be of great interest after surgical operations on contaminated prostheses and after bacteremia in order to prevent the colonization of the device. PMID:27316688

  9. Molecular identification, antifungal susceptibility profile, and biofilm formation of clinical and environmental Rhodotorula species isolates.

    PubMed

    Nunes, Jorge Meneses; Bizerra, Fernando César; Ferreira, Renata Carmona E; Colombo, Arnaldo Lopes

    2013-01-01

    Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC(50)/MIC(90), 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula

  10. Molecular Identification, Antifungal Susceptibility Profile, and Biofilm Formation of Clinical and Environmental Rhodotorula Species Isolates

    PubMed Central

    Nunes, Jorge Meneses; Bizerra, Fernando César; Ferreira, Renata Carmona e

    2013-01-01

    Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC50/MIC90, 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula species

  11. Antibiotic resistance profiles of Pseudomonas aeruginosa isolated from various Greek aquatic environments.

    PubMed

    Olga, Pappa; Apostolos, Vantarakis; Alexis, Galanis; George, Vantarakis; Athena, Mavridou

    2016-05-01

    A large number of antibiotic-resistantP. aeruginosaisolates are continuously discharged into natural water basins mainly through sewage. However, the environmental reservoirs of antibiotic resistance factors are poorly understood. In this study, the antibiotic resistance patterns of 245 isolates from various aquatic sites in Greece were analysed. Twenty-three isolates with resistance patterns cefotaxime-aztreonam-ceftazidime, cefotaxime-aztreonam-meropenem, cefotaxime-ceftazidime-meropenem, cefotaxime-ceftazidime-aztreonam-meropenem and cefotaxime-ceftazidime-cefepime-aztreonam-meropenem were screened phenotypically for the presence of extended spectrum β-lactamases (ESBLs), while 77 isolates with various resistant phenotypes were screened for the presence of class 1 and class 2 integrase genes. The aztreonam-resistant isolates and ESBL producers were the main resistant phenotypes in all habitats tested. In 13/77 isolates class 1 integron was detected, while all tested isolates were negative for the presence of the class 2 integrase gene. CTX-M group 9 β-lactamase was present in a small number of isolates (three isolates) highlighting the emergence of ESBL genes in aquatic environments. As a conclusion, it seems that Greek water bodies could serve as a potential reservoir of resistantP. aeruginosaisolates posing threats to human and animal health. PMID:26917780

  12. [Monitoring and antibiotic resistance profile of tracheal aspirate microbiota in ICU children with severe craniocerebral trauma].

    PubMed

    Lazareva, A V; Katosova, L K; Kryzhanovskaya, O A; Ponomarenko, O A; Karaseva, O V; Gorelik, A L; Mayanskiy, N A

    2014-01-01

    Nosocomial infections and their rational antibiotic treatment represent a major challenge for the healthcare nowadays. In this context, gramnegative bacteria including Pseudomonas aeruginosa, Acinetobacter baumanii and Enterobacteriaceae spp. are etiologically important and characterized by a significant level of antibiotic resistance. To examine dynamics of the respiratory tract colonization by hospital flora, tracheal aspirates obtained at three time points from 69 children with severe craniocerebral trauma during their stay in ICU were analysed. Colonization was observed on the 4th day of the ICU stay with predomination of K. pneumoniae (45%) and A. baumanii (27-37%). P. aeruginosa was detected after the 8th day of the ICU stay with the isolation rate of 33%. Substantial proportions of P. aeruginosa (61%), A. baumanii (78%) and K. pneumoniae (25%) were resistant to carbapenems. In 65 carbapemen resistant isolates, the presence of carbapenemases was examined using PCRs. OXA-48 carbapenemase was detected in 11 out of 14 (78%) K. pneumoniae isolates. Among the A. baumanii isolates, 30/31 (97%) carried OXA-40 and 1/31 (3%) had OXA-23 carbapenemases. None of the examined A. baumanii and K. pneumoniae isolates produced metallo-betalactamases (MBL). In contrast, all 20 carbapenem resistant P. aeruginosa isolates produced a MBL, and in 12 out of 20 (60%) of theme VIM-2 was detected. Thus, gramnegative nosocomial microflora rapidly colonizes ICU patients and has a high level of resistance to antibiotics, including carbapenems. PMID:25975102

  13. Etiologic Agents of Bacterial Sepsis and Their Antibiotic Susceptibility Patterns among Patients Living with Human Immunodeficiency Virus at Gondar University Teaching Hospital, Northwest Ethiopia

    PubMed Central

    Alebachew, Gelila; Teka, Brhanu; Endris, Mengistu; Shiferaw, Yitayal; Tessema, Belay

    2016-01-01

    Background. Bacterial sepsis is a major cause of illness in human immunodeficiency virus infected patients. There is scarce evidence about sepsis among HIV patients in Ethiopia. This study aimed to determine the etiologic agents of bacterial sepsis and their antibiotic susceptibility patterns among HIV infected patients. Methods. A cross-sectional study was carried out from March 1 to May 2, 2013. One hundred patients infected with HIV and suspected of having sepsis were included. Sociodemographic data were collected by interview and blood sample was aseptically collected from study participants. All blood cultures were incubated aerobically at 35°C and inspected daily for 7 days. The positive blood cultures were identified following the standard procedures and antimicrobial susceptibility testing was performed using disk diffusion technique. Data was entered by Epi-info version 3.5.1 and analysis was done using SPSS version 20. Results. Of the study participants, 31 (31%) confirmed bacterial sepsis. The major isolates were 13 (13%) Staphylococcus aureus, 8 (8%) coagulates negative staphylococci, and 3 (3%) viridans streptococci. Majority of the isolates, 25 (80.6%), were multidrug resistant to two or more antimicrobial agents. Conclusions. Bacterial sepsis was a major cause of admission for HIV infected patients predominated by Staphylococcus aureus and coagulase negative staphylococci species and most of the isolates were multidrug resistant. PMID:27314025

  14. Restoration of susceptibility of intracellular methicillin-resistant Staphylococcus aureus to beta-lactams: comparison of strains, cells, and antibiotics.

    PubMed

    Lemaire, Sandrine; Olivier, Aurélie; Van Bambeke, Françoise; Tulkens, Paul M; Appelbaum, Peter C; Glupczynski, Youri

    2008-08-01

    Staphylococcus aureus invades eukaryotic cells. When methicillin-resistant S. aureus (MRSA) ATCC 33591 is phagocytized by human THP-1 macrophages, complete restoration of susceptibility to cloxacillin and meropenem is shown and the strain becomes indistinguishable from MSSA ATCC 25923 due to the acid pH prevailing in phagolysosomes (S. Lemaire et al., Antimicrob. Agents Chemother. 51:1627-1632, 2007). We examined whether this observation can be extended to (i) strains of current clinical and epidemiological interest (three hospital-acquired MRSA [HA-MRSA] strains, two community-acquired MRSA [CA-MRSA] strains, two HA-MRSA strains with the vancomycin-intermediate phenotype, one HA-MRSA strain with the vancomycin-resistant phenotype, and one animal [porcine] MRSA strain), (ii) activated THP-1 cells and nonprofessional phagocytes (keratinocytes, Calu-3 bronchial epithelial cells), and (iii) other beta-lactams (imipenem, oxacillin, cefuroxime, cefepime). All strains showed (i) a marked reduction in MICs in broth at pH 5.5 compared with the MIC at pH 7.4 and (ii) sigmoidal dose-response curves with cloxacillin (0.01x to 100x MIC, 24 h of incubation) after phagocytosis by THP-1 macrophages that were indistinguishable from each other and from the dose-response curve for methicillin-susceptible S. aureus (MSSA) ATCC 25923 (relative potency [50% effect], 6.09x MIC [95% confidence interval {CI}, 4.50 to 8.25]; relative efficacy [change in bacterial counts over the original inoculum for an infinitely large cloxacillin concentration, or maximal effect], -0.69 log CFU [95% CI, -0.79 to -0.58]). Similar dose-response curves for cloxacillin were also observed with MSSA ATCC 25923 and MRSA ATCC 33591 after phagocytosis by activated THP-1 macrophages, keratinocytes, and Calu-3 cells. By contrast, there was a lower level of restoration of susceptibility of MRSA ATCC 33591 to cefuroxime and cefepime after phagocytosis by THP-1 macrophages, even when the data were normalized for

  15. Antibiotic susceptibility of 33 Prevotella strains isolated from Romanian patients with abscesses in head and neck spaces.

    PubMed

    Bancescu, Gabriela; Didilescu, Andreea; Bancescu, Adrian; Bari, Maria

    2015-10-01

    The purpose of this study was to investigate the susceptibility of a series of 33 Prevotella strains isolated from patients with abscesses in the head and neck spaces, presented to one Romanian hospital. The Etest was applied to determine the value of the minimum inhibitory concentrations for: penicillin G, ampicillin, amoxicillin-clavulanate, metronidazole and clindamycin. In addition, the beta-lactamase activity was detected by the chromogenic cephalosporin disc method. The results indicated that 11 isolates were resistant to both penicillin G and ampicillin due to the beta-lactamase production. All the 33 Prevotella strains were susceptible to the other 3 antimicrobial agents tested, except for only one penicillin G - ampicillin resistant isolate of Prevotella buccae (MIC > 32 and MIC = 12 mg/L, respectively), which showed high resistance to clindamycin (MIC > 256 mg/L) too. Our data underline the necessity for antimicrobial testing including monitoring of beta-lactamase production in cases of oro-maxillo-facial mixed anaerobic infections where antimicrobial treatment is required in addition to the surgical drainage. The results of the study indicated that amoxicillin-clavulanate, like metronidazole, was fully active against the tested Prevotella strains. However, local and multicentre surveys on drug resistance among the clinically significant anaerobic isolates should be carried out periodically. PMID:25463968

  16. [In vitro antifungal susceptibility profile of Scopulariopsis brevicaulis isolated from onychomycosis].

    PubMed

    Carrillo-Muñoz, Alfonso Javier; Tur-Tur, Cristina; Cárdenes, Délia; Rojas, Florencia; Giusiano, Gustavo

    2015-08-01

    We studied the in vitro antifungal activity profile of amorolfine (AMR), bifonazole (BFZ), clotrimazole (CLZ), econazole (ECZ), fluconazole (FNZ), itraconazole (ITZ), ketoconazole (KTZ), miconazole (MNZ), oxiconazole (OXZ), tioconazole (TCZ) and terbinafine (TRB) against 26 clinical isolates of Scopulariopsis brevicaulis from patients with onychomycosis by means of an standardized microdilution method. Although this opportunistic filamentous fungi was reported as resistant to several broad-spectrum antifungals agents, obtained data shows a better fungistatic in vitro activity of AMR, OXZ and TRB (0.08, 0.3, and 0.35 mg/L, respectively) in comparison to that of CLZ (0.47 mg/L), ECZ (1.48 mg/L), MNZ (1.56 mg/L, BFZ (2.8 mg/L), TCZ (3.33 mg/L), KTZ (3.73 mg/L). FNZ (178.47 mg/L) and ITZ (4.7 mg/L) showed a reduced in vitro antifungal activity against S. brevicaulis. Obtained MICs show the low in vitro antifungal susceptibility of S. brevicaulis to topical drugs for onychomycosis management, with exceptions (AMR, OZX and TRB). PMID:26200030

  17. Erwinia amylovora modifies phenolic profiles of susceptible and resistant apple through its type III secretion system.

    PubMed

    Pontais, Isabelle; Treutter, Dieter; Paulin, Jean-Pierre; Brisset, Marie-Noëlle

    2008-03-01

    Fire blight is a disease affecting Maloideae caused by the necrogenic bacterium Erwinia amylovora, which requires the type III protein secretion system (TTSS) for pathogenicity. Profiles of methanol-extractable leaf phenolics of two apple (Malus x domestica) genotypes with contrasting susceptibility to this disease were analyzed by HPLC after infection. Some qualitative differences were recorded between the constitutive compositions of the two genotypes but in both of them dihydrochalcones accounted for more than 90% of total phenolics. Principal component analysis separated leaves inoculated with a virulent wild-type strain from those inoculated with a non-pathogenic TTSS-defective mutant or with water. The changes in levels of the various groups of phenolics in response to the virulent bacterium were similar between the two genotypes, with a significant decrease of dihydrochalcones and a significant increase of hydroxycinnamate derivatives. Differences between genotypes were, however, recorded in amplitude and kinetic of variation in these groups. Occurrence of oxidation and polymerization reactions is proposed, based on the browning process of infected tissues, but whether some by-products act in defense as toxic compounds remain to be tested. Among direct antibacterial constitutive compounds present in apple leaves, the dihydrochalcone phloretin only was found at levels close to lethal concentrations in both genotypes. However, E. amylovora exhibited the ability to stabilize this compound at sublethal levels even in the resistant apple, rejecting the hypothesis of its involvement in the resistance of this genotype. PMID:18275458

  18. Predose and Postdose Blood Gene Expression Profiles Identify the Individuals Susceptible to Acetaminophen-Induced Liver Injury in Rats

    PubMed Central

    Lu, Xiaoyan; Hu, Bin; Zheng, Jie; Ji, Cai; Fan, Xiaohui; Gao, Yue

    2015-01-01

    The extent of drug-induced liver injury (DILI) can vary greatly between different individuals. Thus, it is crucial to identify susceptible population to DILI. The aim of this study was to determine whether transcriptomics analysis of predose and postdose rat blood would allow prediction of susceptible individuals to DILI using the widely applied analgesic acetaminophen (APAP) as a model drug. Based on ranking in alanine aminotransferase levels, five most susceptible and five most resistant rats were identified as two sub-groups after APAP treatment. Predose and postdose gene expression profiles of blood samples from these rats were determined by microarray analysis. The expression of 158 genes innately differed in the susceptible rats from the resistant rats in predose data. In order to identify more reliable biomarkers related to drug responses for detecting individuals susceptibility to APAP-induced liver injury (AILI), the changes of these genes' expression posterior to APAP treatment were detected. Through the further screening method based on the trends of gene expression between the two sub-groups before and after drug treatment, 10 genes were identified as potential predose biomarkers to distinguish between the susceptible and resistant rats. Among them, four genes, Incenp, Rpgrip1, Sbf1, and Mmp12, were found to be reproducibly in real-time PCR with an independent set of animals. They were all innately higher expressed in resistant rats to AILI, which are closely related to cell proliferation and tissue repair functions. It indicated that rats with higher ability of cell proliferation and tissue repair prior to drug treatment might be more resistant to AILI. In this study, we demonstrated that combination of predose and postdose gene expression profiles in blood might identify the drug related inter-individual variation in DILI, which is a novel and important methodology for identifying susceptible population to DILI. PMID:26512990

  19. Contamination profiles and mass loadings of macrolide antibiotics and illicit drugs from a small urban wastewater treatment plant.

    PubMed

    Loganathan, Bommanna; Phillips, Malia; Mowery, Holly; Jones-Lepp, Tammy L

    2009-03-01

    Information is limited regarding sources, distribution, environmental behavior, and fate of prescribed and illicit drugs. Wastewater treatment plant (WWTP) effluents can be one of the sources of pharmaceutical and personal care products (PPCP) into streams, rivers and lakes. The objective of this study was to determine the contamination profiles and mass loadings of urobilin (a chemical marker of human waste), macrolide antibiotics (azithromycin, clarithromycin, roxithromycin), and two drugs of abuse (methamphetamine and ecstasy), from a small (<19 mega liters day(-1), equivalent to <5 million gallons per day) wastewater treatment plant in southwestern Kentucky. The concentrations of azithromycin, clarithromycin, methamphetamine and ecstasy in wastewater samples varied widely, ranging from non-detects to 300 ng L(-1). Among the macrolide antibiotics analyzed, azithromycin was consistently detected in influent and effluent samples. In general, influent samples contained relatively higher concentrations of the analytes than the effluents. Based on the daily flow rates and an average concentration of 17.5 ng L(-1) in the effluent, the estimated discharge of azithromycin was 200 mg day(-1) (range 63-400 mg day(-1)). Removal efficiency of the detected analytes from this WWTP were in the following order: urobilin>methamphetamine>azithromycin with percentages of removal of 99.9%, 54.5% and 47%, respectively, indicating that the azithromycin and methamphetamine are relatively more recalcitrant than others and have potential for entering receiving waters. PMID:19121838

  20. Antibiotics conspicuously affect community profiles and richness, but not the density of bacterial cells associated with mucosa in the large and small intestines of mice.

    PubMed

    Puhl, Nathan J; Uwiera, Richard R E; Yanke, L Jay; Selinger, L Brent; Inglis, G Douglas

    2012-02-01

    The influence of three antibiotics (bacitracin, enrofloxacin, and neomycin sulfate) on the mucosa-associated enteric microbiota and the intestines of mice was examined. Antibiotics caused conspicuous enlargement of ceca and an increase in overall length of the intestine. However, there were no pathologic changes associated with increased cecal size or length of the intestine. Conspicuous reductions in the richness of mucosa-associated bacteria and changes to community profiles within the small (duodenum, proximal jejunum, middle jejunum, distal jejunum, and ileum) and large (cecum, ascending colon, and descending colon) intestine occurred in mice administered antibiotics. Communities in antibiotic-treated mice were dominated by a limited number of Clostridium-like (i.e. clostridial cluster XIVa) and Bacteroides species. The richness of mucosa-associated communities within the small and large intestine increased during the 14-day recovery period. However, community profiles within the large intestine did not return to baseline (i.e. relative to the control). Although antibiotic administration greatly reduced bacterial richness, densities of mucosa-associated bacteria were not reduced correspondingly. These data showed that the antibiotics, bacitracin, enrofloxacin, and neomycin sulfate, administered for 21 days to mice did not sterilize the intestine, but did impart a tremendous and prolonged impact on mucosa-associated bacterial communities throughout the small and large intestine. PMID:22185696

  1. A Ferritin Mutant of Mycobacterium tuberculosis Is Highly Susceptible to Killing by Antibiotics and Is Unable To Establish a Chronic Infection in Mice

    PubMed Central

    Pandey, Ruchi

    2012-01-01

    Iron is an essential, elusive, and potentially toxic nutrient for most pathogens, including Mycobacterium tuberculosis. Due to the poor solubility of ferric iron under aerobic conditions, free iron is not found in the host. M. tuberculosis requires specialized iron acquisition systems to replicate and cause disease. It also depends on a strict control of iron metabolism and intracellular iron levels to prevent iron-mediated toxicity. Under conditions of iron sufficiency, M. tuberculosis represses iron acquisition and induces iron storage, suggesting an important role for iron storage proteins in iron homeostasis. M. tuberculosis synthesizes two iron storage proteins, a ferritin (BfrB) and a bacterioferritin (BfrA). The individual contributions of these proteins to the adaptive response of M. tuberculosis to changes in iron availability are not clear. By generating individual knockout strains of bfrA and bfrB, the contribution of each one of these proteins to the maintenance of iron homeostasis was determined. The effect of altered iron homeostasis, resulting from impaired iron storage, on the resistance of M. tuberculosis to in vitro and in vivo stresses was examined. The results show that ferritin is required to maintain iron homeostasis, whereas bacterioferritin seems to be dispensable for this function. M. tuberculosis lacking ferritin suffers from iron-mediated toxicity, is unable to persist in mice, and, most importantly, is highly susceptible to killing by antibiotics, showing that endogenous oxidative stress can enhance the antibiotic killing of this important pathogen. These results are relevant for the design of new therapeutic strategies against M. tuberculosis. PMID:22802345

  2. Prevalence and antibiotic susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA) among primary school children and prisoners in Jimma Town, Southwest Ethiopia

    PubMed Central

    2013-01-01

    Background Staphylococcus aureus infections are increasingly reported from both health institutions and communities around the world. In particular, infections due to methicillin-resistant Staphylococcus aureus (MRSA) strains have been detected worldwide. If MRSA becomes the most common form of S. aureus in a community, it makes the treatment of common infections much more difficult. But, report on the current status of community acquired MRSA in the study area is scanty. Methods Community-based cross sectional study was conducted to evaluate the current prevalence and antibiotic susceptibility pattern of MRSA among primary school children and prisoners in Jimma town. MRSA was detected using Cefoxitin (30μg) disc; and epidemiologic risk factors were assessed using pre-designed questionnaires distributed to the children’s parents and prisoners. A total of 354 nasal swabs were collected from primary school children and prisoners from December 2010 to March 2011 following standards microbiological methods. Results A total of 169 S. aureus isolates were recovered. The overall prevalence of MRSA among the study population was 23.08 % (39/169). Specifically, the prevalence of MRSA among primary school children and prisoners were 18.8% (27/144) and 48% (12/25), respectively. The isolated S. aureus and MRSA displayed multiple drug resistance (MDR) to 2 to 10 antibiotics. The most frequent MDR was Amp/Bac/Ery/Pen/Fox (resistance to Ampicillin, Bacitracin, Erythromycin, Penicillin, and Cefoxitin). Conclusion The present study revealed that MRSA could be prevalent in the healthy community, transmitted from hospital to the community. The high distribution of MRSA could be favored by potential risk factors. Thus, for comprehensive evaluation of the current prevalence of MRSA and design control measures, consideration need to be given to the healthy community besides data coming from health institutions. PMID:23731679

  3. Integrated analysis of three bacterial conjunctivitis trials of besifloxacin ophthalmic suspension, 0.6%: etiology of bacterial conjunctivitis and antibacterial susceptibility profile

    PubMed Central

    Haas, Wolfgang; Gearinger, Lynne S; Usner, Dale W; DeCory, Heleen H; Morris, Timothy W

    2011-01-01

    Background The purpose of this paper is to report on the bacterial species isolated from patients with bacterial conjunctivitis participating in three clinical trials of besifloxacin ophthalmic suspension, 0.6%, and their in vitro antibacterial susceptibility profiles. Methods Microbial data from three clinical studies, conducted at multiple clinical sites in the US and Asia were integrated. Species were identified at a central laboratory, and minimum inhibitory concentrations were determined for various antibiotics, including β-lactams, fluoroquinolones, and macrolides. Results A total of 1324 bacterial pathogens representing more than 70 species were isolated. The most common species were Haemophilus influenzae (26.0%), Streptococcus pneumoniae (22.8%), Staphylococcus aureus (14.4%), and Staphylococcus epidermidis (8.4%). H. influenzae was most frequently isolated among patients aged 1–18 years, while S. aureus was most prevalent among those >65 years. Drug resistance was prevalent: Of H. influenzae isolates, 25.3% were β-lactamase positive and 27.2% of S. pneumoniae isolates were penicillin-intermediate/ resistant; of S. aureus isolates, 13.7% were methicillin-resistant (MRSA), and of these, 65.4% were ciprofloxacin-resistant, while 45.9% of S. epidermidis isolates were methicillin-resistant (MRSE), and, of these, 47.1% were ciprofloxacin-resistant. Besifloxacin was more potent than comparator fluoroquinolones overall, and particularly against Gram-positive bacteria. Against ciprofloxacin-resistant MRSA and MRSE, besifloxacin was four-fold to ≥ 128-fold more potent than other fluoroquinolones. Conclusions While the pathogen distribution in bacterial conjunctivitis has not changed, drug resistance is increasing. Patient age and local antibiotic resistance trends should be considered in the treatment of this ocular infection. Besifloxacin showed broad-spectrum in vitro activity and was particularly potent against multidrug-resistant staphylococcal isolates

  4. High-throughput profiling of antibiotic resistance genes in drinking water treatment plants and distribution systems.

    PubMed

    Xu, Like; Ouyang, Weiying; Qian, Yanyun; Su, Chao; Su, Jianqiang; Chen, Hong

    2016-06-01

    Antibiotic resistance genes (ARGs) are present in surface water and often cannot be completely eliminated by drinking water treatment plants (DWTPs). Improper elimination of the ARG-harboring microorganisms contaminates the water supply and would lead to animal and human disease. Therefore, it is of utmost importance to determine the most effective ways by which DWTPs can eliminate ARGs. Here, we tested water samples from two DWTPs and distribution systems and detected the presence of 285 ARGs, 8 transposases, and intI-1 by utilizing high-throughput qPCR. The prevalence of ARGs differed in the two DWTPs, one of which employed conventional water treatments while the other had advanced treatment processes. The relative abundance of ARGs increased significantly after the treatment with biological activated carbon (BAC), raising the number of detected ARGs from 76 to 150. Furthermore, the final chlorination step enhanced the relative abundance of ARGs in the finished water generated from both DWTPs. The total enrichment of ARGs varied from 6.4-to 109.2-fold in tap water compared to finished water, among which beta-lactam resistance genes displayed the highest enrichment. Six transposase genes were detected in tap water samples, with the transposase gene TnpA-04 showing the greatest enrichment (up to 124.9-fold). We observed significant positive correlations between ARGs and mobile genetic elements (MGEs) during the distribution systems, indicating that transposases and intI-1 may contribute to antibiotic resistance in drinking water. To our knowledge, this is the first study to investigate the diversity and abundance of ARGs in drinking water treatment systems utilizing high-throughput qPCR techniques in China. PMID:26890482

  5. Microscale insights into pneumococcal antibiotic mutant selection windows

    PubMed Central

    Sorg, Robin A.; Veening, Jan-Willem

    2015-01-01

    The human pathogen Streptococcus pneumoniae shows alarming rates of antibiotic resistance emergence. The basic requirements for de novo resistance emergence are poorly understood in the pneumococcus. Here we systematically analyse the impact of antibiotics on S. pneumoniae at concentrations that inhibit wild type cells, that is, within the mutant selection window. We identify discrete growth-inhibition profiles for bacteriostatic and bactericidal compounds, providing a predictive framework for distinction between the two classifications. Cells treated with bacteriostatic agents show continued gene expression activity, and real-time mutation assays link this activity to the development of genotypic resistance. Time-lapse microscopy reveals that antibiotic-susceptible pneumococci display remarkable growth and death bistability patterns in response to many antibiotics. We furthermore capture the rise of subpopulations with decreased susceptibility towards cell wall synthesis inhibitors (heteroresisters). We show that this phenomenon is epigenetically inherited, and that heteroresistance potentiates the accumulation of genotypic resistance. PMID:26514094

  6. Microscale insights into pneumococcal antibiotic mutant selection windows.

    PubMed

    Sorg, Robin A; Veening, Jan-Willem

    2015-01-01

    The human pathogen Streptococcus pneumoniae shows alarming rates of antibiotic resistance emergence. The basic requirements for de novo resistance emergence are poorly understood in the pneumococcus. Here we systematically analyse the impact of antibiotics on S. pneumoniae at concentrations that inhibit wild type cells, that is, within the mutant selection window. We identify discrete growth-inhibition profiles for bacteriostatic and bactericidal compounds, providing a predictive framework for distinction between the two classifications. Cells treated with bacteriostatic agents show continued gene expression activity, and real-time mutation assays link this activity to the development of genotypic resistance. Time-lapse microscopy reveals that antibiotic-susceptible pneumococci display remarkable growth and death bistability patterns in response to many antibiotics. We furthermore capture the rise of subpopulations with decreased susceptibility towards cell wall synthesis inhibitors (heteroresisters). We show that this phenomenon is epigenetically inherited, and that heteroresistance potentiates the accumulation of genotypic resistance. PMID:26514094

  7. Effects of Subinhibitory Concentrations of Antibiotics on Colonization Factor Expression by Moxifloxacin-Susceptible and Moxifloxacin-Resistant Clostridium difficile Strains▿

    PubMed Central

    Denève, Cécile; Bouttier, Sylvie; Dupuy, Bruno; Barbut, Frédéric; Collignon, Anne; Janoir, Claire

    2009-01-01

    Recent outbreaks of Clostridium difficile infection have been related to the emergence of the NAP1/027 epidemic strain. This strain demonstrates increased virulence and resistance to the C-8-methoxyfluoroquinolones gatifloxacin and moxifloxacin. These antibiotics have been implicated as major C. difficile infection-inducing agents. We investigated by real-time reverse transcription-PCR the impact of subinhibitory concentrations of ampicillin, clindamycin, ofloxacin, and moxifloxacin on the expression of genes encoding three colonization factors, the protease Cwp84, the high-molecular-weight S-layer protein, and the fibronectin-binding protein Fbp68. We have previously shown in six non-NAP1/027 moxifloxacin-susceptible strains that the presence of ampicillin or clindamycin induced an upregulation of these genes, whereas the presence of fluoroquinolones did not. The objective of this study was to analyze the expression of these genes under the same conditions in four NAP1/027 strains, one moxifloxacin susceptible and three moxifloxacin resistant. Two in vitro-selected moxifloxacin-resistant mutants were also analyzed. Moxifloxacin resistance was associated with the Thr82→Ile substitution in GyrA in all but one of the moxifloxacin-resistant strains. The expression of cwp84 and slpA was strongly increased after culture with ampicillin or clindamycin in NAP1/027 strains. Interestingly, after culture with fluoroquinolones, the expression of cwp84 and slpA was only increased in four moxifloxacin-resistant strains, including the NAP1/027 strains and one of the in vitro-selected mutants. The overexpression of cwp84 was correlated with increased production of the protease Cwp84. The historical NAP1/027 moxifloxacin-susceptible strain and its mutant appear to be differently regulated by fluoroquinolones. Overall, fluoroquinolones appear to favor the expression of some colonization factor-encoding genes in resistant C. difficile strains. The fluoroquinolone resistance of the

  8. [Investigation of antibiotic resistance patterns and reduced vancomycin susceptibilities of methicillin-resistant Staphylococcus aureus isolates: a multi-center study].

    PubMed

    Çıkman, Aytekin; Aydın, Merve; Gülhan, Barış; Parlak, Mehmet; Gültepe, Bilge; Kalaycı, Yıldız; Bayındır Bilmen, Fulya; Solmaz, Sinem; Özekinci, Tuncer

    2015-04-01

    The aims of this study were to determine the minimum inhibitory concentration (MIC) values of vancomycin, teicoplanin, daptomycin, quinupristin/dalfopristin, linezolid, tigecycline, chloramphenicol, rifampicin, ofloxacin and tetracycline and to investigate the reduced vancomycin susceptibility among methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in hospitals located in different geographical regions of Turkey. A total of 100 MRSA strains isolated from patients (of which 50% were from intensive care units) hospitalized in seven centers in Turkey [Istanbul (n= 15), Ankara (n= 15), Izmir (n= 15), Adana (n= 15), Diyarbakir (n=15), Erzincan (n= 15), Van (n= 10)], between August 2013 - August 2014, were included in the study. Fourty-three strains were isolated from blood, whereas 21 were from lower respiratory tract, 17 from wounds, eight from catheters, six from urine, four from nasal swab and one from cerebrospinal fluid samples. Methicillin resistance of the isolates was determined by using cefoxitin (30 µg) disk with standard disk diffusion method, while the MIC values of other antibiotics were determined with E-test in accordance with the recommendations of Clinical and Laboratory Standards Institute (CLSI). MIC results obtained for quinupristin-dalfopristin (Q/D) were evaluated according to the CLSI criteria used for methicillin-susceptible S.aureus and for tigecycline according to the criteria recommended by the Food and Drug Administration for MRSA. Primarily, agar screening method (ASM) was used for determination of vancomycin-intermediate S.aureus (VISA) and heterogeneous VISA (hVISA) strains. Brain heart infusion agar containing 6 µg/ml vancomycin was used in ASM, and the strains with suspicion of VISA/hVISA were screened by standard E-test and macro E-test methods. All MRSA strains were susceptible to vancomycin, teicoplanin, daptomycin, Q/D and linezolid by E-test method; and their rates of susceptibility for tigecycline

  9. Circuit-wide Transcriptional Profiling Reveals Brain Region-Specific Gene Networks Regulating Depression Susceptibility.

    PubMed

    Bagot, Rosemary C; Cates, Hannah M; Purushothaman, Immanuel; Lorsch, Zachary S; Walker, Deena M; Wang, Junshi; Huang, Xiaojie; Schlüter, Oliver M; Maze, Ian; Peña, Catherine J; Heller, Elizabeth A; Issler, Orna; Wang, Minghui; Song, Won-Min; Stein, Jason L; Liu, Xiaochuan; Doyle, Marie A; Scobie, Kimberly N; Sun, Hao Sheng; Neve, Rachael L; Geschwind, Daniel; Dong, Yan; Shen, Li; Zhang, Bin; Nestler, Eric J

    2016-06-01

    Depression is a complex, heterogeneous disorder and a leading contributor to the global burden of disease. Most previous research has focused on individual brain regions and genes contributing to depression. However, emerging evidence in humans and animal models suggests that dysregulated circuit function and gene expression across multiple brain regions drive depressive phenotypes. Here, we performed RNA sequencing on four brain regions from control animals and those susceptible or resilient to chronic social defeat stress at multiple time points. We employed an integrative network biology approach to identify transcriptional networks and key driver genes that regulate susceptibility to depressive-like symptoms. Further, we validated in vivo several key drivers and their associated transcriptional networks that regulate depression susceptibility and confirmed their functional significance at the levels of gene transcription, synaptic regulation, and behavior. Our study reveals novel transcriptional networks that control stress susceptibility and offers fundamentally new leads for antidepressant drug discovery. PMID:27181059

  10. Candida palmioleophila: characterization of a previously overlooked pathogen and its unique susceptibility profile in comparison with five related species.

    PubMed

    Jensen, Rasmus H; Arendrup, Maiken C

    2011-02-01

    Candida palmioleophila has previously been misidentified as C. famata or C. guilliermondii. We have investigated traditional and modern identification methods for the identification of this and related species. Forty-one clinical isolates previously identified as C. famata or C. guilliermondii and 8 reference strains were included. Color development on CHROMagar, growth temperature ranges, micromorphologies, carbon assimilation (ID32C), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) profiles, and susceptibility profiles (mica- and anidulafungin and itra-, vori-, posa-, and fluconazole MICs were determined by EUCAST method EDef 7.1, and caspofungin MICs were determined by Etest) were determined, and results were compared to those of molecular identification (ITS1 and ITS2 sequencing). The following five different species were identified among the clinical isolates by sequencing, but no C. famata isolates were found: C. guilliermondii (22 isolates), C. palmioleophila (8 isolates), C. fermentati (6 isolates), C. lusitaniae (3 isolates), and C. intermedia (2 isolates). C. palmioleophila developed a distinct scintillating color of turquoise to rose, grew at 40°C, and failed to produce pseudohyphae within 14 days. The ID32C profile for 7/9 C. palmioleophila isolates was 5367352315, and all were unable to hydrolyze esculin (Esc). The six related species were well discriminated by MALDI-TOF MS. The susceptibility pattern for C. palmioleophila was unique, as the echinocandin MICs were low (range, 0.008 to 0.125 μg/ml) and fluconazole MICs were high (range, 8 to >16 μg/ml). Correct identification of C. palmioleophila is important due to its unique susceptibility profile. Identification is possible yet laborious with conventional techniques, whereas MALDI-TOF MS easily separated the related species. PMID:21147953

  11. Bacterial profile and antimicrobial susceptibility patterns of otitis media in Ayder Teaching and Referral Hospital, Mekelle University, Northern Ethiopia.

    PubMed

    Wasihun, Araya Gebereyesus; Zemene, Yilikal

    2015-01-01

    Middle Ear infection is a common problem for both children and adults particularly in resource limited countries. Nevertheless, in Ethiopia and particularly in the study area, there is scarcity of recent data that indicate the magnitude of the problem. Thus this study aimed to identify bacterial isolates and determine their drug susceptibility patterns from patients who had ear infection. Cross sectional study was carried out on patients with ear infection and who visited the Ear, Nose and Throat clinic of Ayder referral and teaching hospital from November 2014 to June 2015. Middle ear discharges were collected and processed for bacterial culture and antimicrobial susceptibility testing using standard bacteriological techniques. Clinical and demographic data were collected using standard questionnaire. Data were entered and analyzed using SPSS version 20 software and p value of < 0.05 was considered statistically significant. Of the total of 162 patients with ear discharges, 68.5 % were from rural areas, 71 % with chronic infection, 54.9 % referred cases and 67.3 % of them had decreased hearing status. Pathogens were isolated from 157 (98.2 %) of the patients with a total of 216 isolates. Staphylococcus aureus 46 (28.4 %), Proteus mirabilis 39 (24.1 %), Pseudomonas aeruginosa 27 (16.7 %), Klebsiella spp. and Haemophilus influenzae 18 (11.1 % each) were the dominant bacteria. Out of the individuals with ear infection, single and mixed bacterial infection was seen among 185 (90.7 %) and 59 (39.5 %) respectively. Age group of 0-5 years (p = 0.02), chronic patients (p = 0.042) and referred cases (p = 0.045) showed high bacterial isolates. High resistance was seen to most antibiotics. Ciprofloxacin, Gentamicin Norfloxacin and Erythromycin were effective against isolated bacteria. The overall multi drug resistance rate of bacteria in this study was 74.5 %. Prevalence of bacteria associated with otitis media and multidrug resistance was very high in

  12. Nosocomial candidiasis in Rio de Janeiro State: Distribution and fluconazole susceptibility profile.

    PubMed

    Neufeld, Paulo Murillo; Melhem, Marcia de Souza Carvalho; Szeszs, Maria Walderez; Ribeiro, Marcos Dornelas; Amorim, Efigênia de Lourdes Teixeira; da Silva, Manuela; Lazéra, Marcia dos Santos

    2015-06-01

    One hundred and forty-one Candida species isolated from clinical specimens of hospitalized patients in Rio de Janeiro, Brazil, during 2002 to 2007, were analized in order to evaluate the distribution and susceptibility of these species to fluconazole. Candida albicans was the most frequent species (45.4%), followed by C. parapsilosis sensu lato (28.4%), C. tropicalis (14.2%), C. guilliermondii (6.4%), C. famata (2.8%), C. glabrata (1.4%), C. krusei (0.7%) and C. lambica (0.7%). The sources of fungal isolates were blood (47.5%), respiratory tract (17.7%), urinary tract (16.3%), skin and mucous membrane (7.1%), catheter (5.6%), feces (2.1%) and mitral valve tissue (0.7%). The susceptibility test was performed using the methodology of disk-diffusion in agar as recommended in the M44-A2 Document of the Clinical and Laboratory Standards Institute (CLSI). The majority of the clinical isolates (97.2%) was susceptible (S) to fluconazole, although three isolates (2.1%) were susceptible-dose dependent (S-DD) and one of them (0.7%) was resistant (R). The S-DD isolates were C. albicans, C. parapsilosis sensu lato and C. tropicalis. One isolate of C. krusei was resistant to fluconazole. This work documents the high susceptibility to fluconazole by Candida species isolated in Rio de Janeiro, Brazil. PMID:26273262

  13. Comparative analysis of virulence determinants, antibiotic susceptibility patterns and serogrouping of atypical enteropathogenic Escherichia coli versus typical enteropathogenic E. coli in India.

    PubMed

    Malvi, Supriya; Appannanavar, Suma; Mohan, Balvinder; Kaur, Harsimran; Gautam, Neha; Bharti, Bhavneet; Kumar, Yashwant; Taneja, Neelam

    2015-10-01

    The epidemiology of enteropathogenic Escherichia coli (EPEC) and the significance of isolation of atypical EPEC (aEPEC) in childhood diarrhoea have not been well studied in an Indian context. A comparative study was undertaken to investigate virulence determinants, antibiotic susceptibility patterns and serogrouping of typical EPEC (tEPEC) versus aEPEC causing diarrhoea in children. A total of 400 prospective and 500 retrospective E. coli isolates were included. PCR was performed for eae, bfpA, efa, nleB, nleE, cdt, ehxA and paa genes. The Clinical and Laboratory Standards Institute's disc diffusion test was used to determine the antimicrobial susceptibility. Phenotypic screening of extended spectrum β-lactamases (ESBLs), AmpC and Klebsiella pneumoniae carbapenemase (KPC) production, and molecular detection of bla(NDM-1), bla(VIM), bla(CTX-M-15), bla(IMP) and bla(KPC) were performed. aEPEC (57.6 %) were more common as compared with tEPEC (42.3 %). The occurrence of virulence genes was observed to be three times higher in aEPEC as compared with tEPEC, efa1 (14.7 % of aEPEC, 4 % of tEPEC) being the most common. Most of the isolates did not belong to the classical EPEC O-serogroups. The highest resistance was observed against amoxicillin (93.22 %) followed by quinolones (83 %), cephalosporins (37.28 %), cotrimoxazole (35.59 %) and carbapenems (30.5 %). Overall equal numbers of aEPEC (41.17 %) and tEPEC (40 %) were observed to be multidrug-resistant. Fifteen EPEC strains demonstrated presence of ESBLs, five produced AmpC and four each produced metallo-β-lactamases and KPC-type carbapenemases; eight, seven and one isolate(s) each were positive for bla(VIM), bla(CTX-M-15) and bla(NDM-1), respectively. Here, to the best of our knowledge, we report for the first time on carbapenem resistance and the presence of bla(NDM-1) and bla(CTX-M-15) in EPEC isolates from India. PMID:26233663

  14. Methicillin Resistant Staphylococcus aureus among HIV Infected Pediatric Patients in Northwest Ethiopia: Carriage Rates and Antibiotic Co-Resistance Profiles

    PubMed Central

    Lemma, Martha Tibebu; Zenebe, Yohannes; Tulu, Begna; Mekonnen, Daniel; Mekonnen, Zewdie

    2015-01-01

    Background MRSA infections are becoming more prevalent throughout the HIV community. MRSA infections are a challenge to both physicians and patients due to limited choice of therapeutic options and increased cost of care. Objectives This study was aimed to determine the prevalence of colonization and co-resistance patterns of MRSA species among HIV positive pediatric patients in the Amhara National Regional State, Northwest Ethiopia. Methods Culture swabs were collected from the anterior nares, the skin and the perineum of 400 participants. In vitro antimicrobial susceptibility testing was done on Muller Hinton Agar by the Kirby-Bauer disk diffusion method, using 30 μg cefoxitin (OXOID, ENGLAND) according to the recommendations of the Clinical and Laboratory Standards Institute. Methicillin sensitivity/resistance was tested using cefoxitin. Data was analyzed by descriptive statistics and logistic regression model using Epi Info 7. Results S. aureus was detected in 206 participants (51.5%). The prevalence of MRSA colonization in this study was 16.8%. Colonization by S. aureus was associated with male gender (OR = 0.5869; 95% CI: 0.3812–0.9036; p-value = 0.0155), history of antibiotic use over the previous 3 months (OR = 2.3126; 95% CI: 1.0707–4.9948; p-value = 0.0329) and having CD4 T-cell counts of more than 350 x 106 cells / L (OR = 0.5739; 95% CI = 0.3343–0.9851; p-value = 0.0440). Colonization by MRSA was not associated with any one of the variables. Concomitant resistance of the MRSA to clindamycin, chloramphenicol, co-trimoxazole, ceftriaxone, erythromycin and tetracycline was 7.6%, 6%, 5.25%, 20.9%, 23.9% and 72.1%, respectively. Conclusion High rates of colonization by pathogenic MRSA strains is observed among HIV positive pediatric patients in the Amhara National Regional state. PMID:26421927

  15. In vitro bioactivity, cytocompatibility, and antibiotic release profile of gentamicin sulfate-loaded borate bioactive glass/chitosan composites.

    PubMed

    Cui, Xu; Gu, Yifei; Li, Le; Wang, Hui; Xie, Zhongping; Luo, Shihua; Zhou, Nai; Huang, Wenhai; Rahaman, Mohamed N

    2013-10-01

    Borate bioactive glass-based composites have been attracting interest recently as an osteoconductive carrier material for local antibiotic delivery. In the present study, composites composed of borate bioactive glass particles bonded with a chitosan matrix were prepared and evaluated in vitro as a carrier for gentamicin sulfate. The bioactivity, degradation, drug release profile, and compressive strength of the composite carrier system were studied as a function of immersion time in phosphate-buffered saline at 37 °C. The cytocompatibility of the gentamicin sulfate-loaded composite carrier was evaluated using assays of cell proliferation and alkaline phosphatase activity of osteogenic MC3T3-E1 cells. Sustained release of gentamicin sulfate occurred over ~28 days in PBS, while the bioactive glass converted continuously to hydroxyapatite. The compressive strength of the composite loaded with gentamicin sulfate decreased from the as-fabricated value of 24 ± 3 MPa to ~8 MPa after immersion for 14 days in PBS. Extracts of the soluble ionic products of the borate glass/chitosan composites enhanced the proliferation and alkaline phosphatase activity of MC3T3-E1 cells. These results indicate that the gentamicin sulfate-loaded composite composed of chitosan-bonded borate bioactive glass particles could be useful clinically as an osteoconductive carrier material for treating bone infection. PMID:23820937

  16. Strategies to Minimize Antibiotic Resistance

    PubMed Central

    Lee, Chang-Ro; Cho, Ill Hwan; Jeong, Byeong Chul; Lee, Sang Hee

    2013-01-01

    Antibiotic resistance can be reduced by using antibiotics prudently based on guidelines of antimicrobial stewardship programs (ASPs) and various data such as pharmacokinetic (PK) and pharmacodynamic (PD) properties of antibiotics, diagnostic testing, antimicrobial susceptibility testing (AST), clinical response, and effects on the microbiota, as well as by new antibiotic developments. The controlled use of antibiotics in food animals is another cornerstone among efforts to reduce antibiotic resistance. All major resistance-control strategies recommend education for patients, children (e.g., through schools and day care), the public, and relevant healthcare professionals (e.g., primary-care physicians, pharmacists, and medical students) regarding unique features of bacterial infections and antibiotics, prudent antibiotic prescribing as a positive construct, and personal hygiene (e.g., handwashing). The problem of antibiotic resistance can be minimized only by concerted efforts of all members of society for ensuring the continued efficiency of antibiotics. PMID:24036486

  17. Metabolic Profiling of Xylem Sap from Pierce’s Disease Resistant and Susceptible Grapevines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pierce’s Disease (PD) of grapevines is caused by a gram-negative, xylem-limited bacterium Xylella fastidiosa (Xf). All Vitis vinifera-based cultivars are highly susceptible to Xf infection. However, some grape species from the southern United States such as V. arizonica, V. Shuttleworthii, and Musca...

  18. Effects of residual antibiotics in groundwater on Salmonella typhimurium: changes in antibiotic resistance, in vivo and in vitro pathogenicity.

    PubMed

    Haznedaroglu, Berat Z; Yates, Marylynn V; Maduro, Morris F; Walker, Sharon L

    2012-01-01

    An outbreak-causing strain of Salmonella enterica serovar Typhimurium was exposed to groundwater with residual antibiotics for up to four weeks. Representative concentrations (0.05, 1, and 100 μg L(-1)) of amoxicillin, tetracycline, and a mixture of several other antibiotics (1 μg L(-1) each) were spiked into artificially prepared groundwater (AGW). Antibiotic susceptibility analysis and the virulence response of stressed Salmonella were determined on a weekly basis by using human epithelial cells (HEp2) and soil nematodes (C. elegans). Results have shown that Salmonella typhimurium remains viable for long periods of exposure to antibiotic-supplemented groundwater; however, they failed to cultivate as an indication of a viable but nonculturable state. Prolonged antibiotics exposure did not induce any changes in the antibiotic susceptibility profile of the S. typhimurium strain used in this study. S. typhimurium exposed to 0.05 and 1 μg L(-1) amoxicillin, and 1 μg L(-1) tetracycline showed hyper-virulent profiles in both in vitro and in vivo virulence assays with the HEp2 cells and C. elegans respectively, most evident following 2nd and 3rd weeks of exposure. PMID:22051852

  19. In Vitro Susceptibility Profiles of Eight Antifungal Drugs against Clinical and Environmental Strains of Phaeoacremonium

    PubMed Central

    Badali, Hamid; Khodavaisy, Sadegh; Fakhim, Hamed; de Hoog, G. Sybren; Chowdhary, Anuradha

    2015-01-01

    In vitro susceptibilities of a worldwide collection of molecularly identified Phaeoacremonium strains (n = 43) belonging to seven species and originating from human and environmental sources were determined for eight antifungal drugs. Voriconazole had the lowest geometric mean MIC (0.35 μg/ml), followed by posaconazole (0.37 μg/ml), amphotericin B (0.4 μg/ml), and isavuconazole (1.16 μg/ml). Caspofungin, anidulafungin, fluconazole, and itraconazole had no activity. PMID:26369976

  20. Keratitis due to Fusarium langsethiae: clinical profile, molecular identification, and susceptibility to antifungals.

    PubMed

    Vasantha Ruban, Vasanthakumar; Geraldine, Pitchairaj; Kaliamurthy, Jayaraman; Jesudasan, Christadoss Arul Nelson; Thomas, Philip Aloysius

    2015-06-01

    We report a case of keratitis due to Fusarium langsethiae in a 56-year-old man. The patient presented with pain and tearing of 10 days duration in the right eye, which had sustained a paddy stalk injury. On examination, a hypopyon corneal ulcer was noted in the right eye. Multiple scrapings were obtained from the affected part of the cornea. A lactophenol cotton blue wet mount and a Gram-stained smear of scrapings were made. Scrapings were also inoculated on various culture media, including Sabouraud dextrose agar (SDA). A fungal etiology was sought by conventional microbiological techniques and polymerase chain reaction. In vitro susceptibility testing was performed by an agar dilution method. Direct microscopy of corneal scrapings revealed septate hyphae, leading to initiation of intensive topical therapy with natamycin (5 %). However, the keratitis progressed, necessitating therapeutic penetrating keratoplasty. White, powdery-like colonies, with abundant aerial mycelium, were recovered on SDA from corneal scrape material. Based on macroscopic and microscopic morphological features, the isolated fungus was initially identified as a Fusarium species. Sequence analysis of the 28S rRNA region of the fungal genome led to a specific identification of F. langsethiae. Antifungal susceptibility testing results suggested that the strain isolated was susceptible to voriconazole, ketoconazole, and itraconazole. To our knowledge, this is the first reported case of keratitis due to F. langsethiae; attention is drawn to the unique characteristics of the fungal isolate, difficulties in identification and non-responsiveness to medical therapy. PMID:25645251

  1. In Vitro Antifungal Susceptibility Profiles of Candida albicans Complex Isolated from Patients with Respiratory Infections.

    PubMed

    Sharifynia, Somayeh; Badali, Hamid; Sharifi Sorkherizi, Mina; Shidfar, Mohammad Reza; Hadian, Atefe; Shahrokhi, Shadi; Ghandchi, Ghazale; Rezaie, Sassan

    2016-06-01

    Candidiasis, the main opportunistic fungal infection has been increased over the past decades. This study aimed to characterize C.albicans species complex (C.albicans, C.dubliniensis, and C.africana) isolated from patients with respiratory infections by molecular tools and in vitro antifungal susceptibilities by using broth microdilution method according to CLSI M27-A3 guidelines. Totally, 121 respiratory samples were collected from patients with respiratory infections. Of these, 83 strains were germ tube positive and green colonies on chromogenic media, so initially identified as C.albicans species complex and subsequently were classified as C.albicans (89.15%), C.dubliniensis (9.63%), and C.africana (1.2%) based on PCR-RFLP and amplification of hwp1 gene. Minimum inhibitory concentration (MICs) results showed that all tested isolates of C.albicans complex were highly susceptible to triazole drugs. However, caspofungin had highest activity against C.albicans, C.dubliniensis, and C.africana. Our findings indicated the variety of antifungal resistance of Candida strains in different areas. These results may increase the knowledge about the local distribution of the mentioned strains as well as their antifungal susceptibility pattern which play an important role in appropriate therapy. PMID:27306344

  2. Antibiotic Resistance

    MedlinePlus

    ... lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able ... resistant to several common antibiotics. To help prevent antibiotic resistance Don't use antibiotics for viruses like colds ...

  3. Bacteriological Profile and Antimicrobial Susceptibility Pattern of Blood Culture Isolates among Septicemia Suspected Children in Selected Hospitals Addis Ababa, Ethiopia

    PubMed Central

    Negussie, Adugna; Mulugeta, Gebru; Bedru, Ahmed; Ali, Ibrahim; Shimeles, Damte; Lema, Tsehaynesh; Aseffa, Abraham

    2015-01-01

    Background Blood stream infections are major cause of morbidity and mortality in children in developing countries. The emerging of causative agents and resistance to various antimicrobial agents are increased from time to time. The main aim of this study was to determine the bacterial agents and antimicrobial susceptibility patterns among children suspected of having septicemia. Methods A cross sectional study involved about 201 pediatric patients (≤ 12 years) was conducted from October 2011 to February 2012 at pediatric units of TikurAnbessa Specialized Hospital and Yekatit 12 Hospital. Standard procedure was followed for blood sample collection, isolate identifications and antimicrobial susceptibility testing. Results Among 201 study subjects 110 (54.7%) were males. Majority 147 (73.1%) of them were neonates (≤ 28 days). The mean length of hospital stay before sampling was 4.29 days. Out of the 201 tested blood samples, blood cultures were positive in 56 (27.9%).Gram negative and Gram positive bacteria constituted 29(51.8%) and 26(46.4%), respectively. The most frequent pathogen found was Staphylococcus aureus 13 (23.2%), followed by Serratia marcescens 12(21.4%), CoNS 11(19.6%), klebsiella spp 9(16%) and Salmonella spp 3(5.4%). Majority of bacterial isolates showed high resistance to Ampicillin, Penicillin, Co-trimoxazole, Gentamicin and Tetracycline which commonly used in the study area. Conclusion Majority of the isolates were multidrug resistant. These higher percentages of multi-drug resistant emerged isolates urge us to take infection prevention measures and to conduct other large studies for appropriate empiric antibiotic choice. PMID:26997847

  4. Comparative antigen-induced gene expression profiles unveil novel aspects of susceptibility/resistance to adjuvant arthritis in rats.

    PubMed

    Yu, Hua; Lu, Changwan; Tan, Ming T; Moudgil, Kamal D

    2013-12-01

    Lewis (LEW) and Wistar Kyoto (WKY) rats of the same major histocompatibility complex (MHC) haplotype (RT.1(l)) display differential susceptibility to adjuvant-induced arthritis (AIA). LEW are susceptible while WKY are resistant to AIA. To gain insights into the mechanistic basis of these disparate outcomes, we compared the gene expression profiles of the draining lymph node cells (LNC) of these two rat strains early (day 7) following a potentially arthritogenic challenge. LNC were tested both ex vivo and after restimulation with the disease-related antigen, mycobacterial heat-shock protein 65. Biotin-labeled fragment cRNA was generated from RNA of LNC and then hybridized with an oligonucleotide-based DNA microarray chip. The differentially expressed genes (DEG) were compared by limiting the false discovery rate to <5% and fold change ≥2.0, and their association with quantitative trait loci (QTL) was analyzed. This analysis revealed overall a more active immune response in WKY than LEW rats. Important differences were observed in the association of DEG with QTL in LEW vs. WKY rats. Both the number of upregulated DEG associated with rat arthritis-QTL and their level of expression were relatively higher in LEW when compared to WKY rat; however, the number of downregulated DEG-associated with rat arthritis-QTL as well as AIA-QTL were found to be higher in WKY than in LEW rats. In conclusion, distinct gene expression profiles define arthritis-susceptible versus resistant phenotype of MHC-compatible inbred rats. These results would advance our understanding of the pathogenesis of autoimmune arthritis and might also offer potential novel targets for therapeutic purposes. PMID:23911410

  5. Antimicrobial susceptibility profiles of Salmonella enterica serotypes recovered from pens of commercial feedlot cattle using different types of composite samples.

    PubMed

    Alam, Mohammad Jahangir; Renter, David; Taylor, Ethel; Mina, Diana; Moxley, Rodney; Smith, David

    2009-04-01

    Salmonella enterica in cattle production systems may be associated with important human and animal disease issues. However, tremendous diversity exists among Salmonella recovered, and more information is needed about strains of greatest potential health concern, particularly those that are multidrug resistant (MDR). By characterizing Salmonella isolates from commercial feedlot pens, this study aimed to evaluate the strain diversity and prevalence of MDR Salmonella from different types of composite pen samples. Antimicrobial susceptibility profiles, serotype, and presence or absence of the integron-encoded intI1 gene were determined for 530 Salmonella isolates recovered using composite rope (n = 335), feces (n = 59), and water (n = 136) samples from 21 pens in 3 feedlots. The study investigated only pens with available isolates from multiple sample types. Most isolates (83.0%) of the 19 Salmonella serotypes identified were susceptible or intermediately susceptible to all the antimicrobials evaluated. Resistance to sulfisoxazole (14.9%), streptomycin (3.8%), and tetracycline (3.6%) were the most common. None of the isolates tested positive for a class 1 integron, and only 2.5% were resistant to multiple antimicrobials. All the MDR isolates, namely, serotypes Uganda (n = 9), Typhimurium (n = 2), and Give (n = 2), were resistant to at least five antimicrobials. Most MDR isolates (n = 11) were from two pens during 1 week within one feedlot. Overall, many Salmonella isolates collected within a pen were similar in terms of serotype and antimicrobial susceptibility regardless of sample type. However, MDR Salmonella and rare serotypes were not recovered frequently enough to suggest a general strategy for appropriate composite sampling of feedlot cattle populations for Salmonella detection and monitoring. PMID:19219500

  6. Serotypes and Antibiotic Susceptibility of Streptococcus pneumoniae Isolates from Invasive Pneumococcal Disease and Asymptomatic Carriage in a Pre-vaccination Period, in Algeria

    PubMed Central

    Ziane, Hanifa; Manageiro, Vera; Ferreira, Eugénia; Moura, Inês B.; Bektache, Soumia; Tazir, Mohamed; Caniça, Manuela

    2016-01-01

    In Algeria, few data is available concerning the distribution of pneumococcal serotypes and respective antibiotic resistance for the current pre-vaccination period, which is a public health concern. We identified the most frequent Streptococcus pneumoniae serogroup/types implicated in invasive pneumococcal disease (IPD; n = 80) and carriage (n = 138) in Algerian children younger than 5 years old. Serogroup/types of 78 IPD isolates were identified by capsular typing using a sequential multiplex PCR. Overall, serotypes 14, 19F, 6B, 23F, 18C, 1, 5, 7F, 19A, and 3 (55% of PCV7 serotypes, 71.3% of PCV10, and 90% of PCV13) were identified. Additionally, 7.5% of the non-vaccine serotypes 6C, 9N/L, 20, 24F, 35B, and 35F, were observed. In the case of S. pneumoniae asymptomatic children carriers, the most common serogroup/types were 6B, 14, 19F, 23F, 4, 9V/A, 1, 19A, 6A, and 3 (42.7% of PCV7 serotypes, 44.2% of PCV10, and 58% of PCV13). For 6.1% of the cases co-colonization was detected. Serotypes 14, 1, 5, and 19A were more implicated in IPD (p < 0.01), whereas serotype 6A was exclusively isolated from carriers (p < 0.01). Deaths associated with IPD were related to serotypes 19A, 14, 18C, and one non-typeable isolate. Among IPD related to vaccine serotypes, the rates of penicillin non-susceptible isolates were higher in no meningitis cases (80%) than in meningitis (66.7%), with serotypes 14, 19A, 19F, and 23F presenting the highest MIC levels (>2μg/ml). Resistance to cefotaxime was higher in isolates from meningitis (40.5%); however, resistance to erythromycin and co-trimoxazole (>40%) was more pronounced in no-meningeal forms. Overall, our results showed that PCV13 conjugate vaccine would cover up to 90% of the circulating isolates associated with IPD in Algeria, highlighting the importance of monitoring the frequency of S. pneumoniae serogroups/types during pre- and post-vaccination periods. PMID:27379023

  7. Serotypes and Antibiotic Susceptibility of Streptococcus pneumoniae Isolates from Invasive Pneumococcal Disease and Asymptomatic Carriage in a Pre-vaccination Period, in Algeria.

    PubMed

    Ziane, Hanifa; Manageiro, Vera; Ferreira, Eugénia; Moura, Inês B; Bektache, Soumia; Tazir, Mohamed; Caniça, Manuela

    2016-01-01

    In Algeria, few data is available concerning the distribution of pneumococcal serotypes and respective antibiotic resistance for the current pre-vaccination period, which is a public health concern. We identified the most frequent Streptococcus pneumoniae serogroup/types implicated in invasive pneumococcal disease (IPD; n = 80) and carriage (n = 138) in Algerian children younger than 5 years old. Serogroup/types of 78 IPD isolates were identified by capsular typing using a sequential multiplex PCR. Overall, serotypes 14, 19F, 6B, 23F, 18C, 1, 5, 7F, 19A, and 3 (55% of PCV7 serotypes, 71.3% of PCV10, and 90% of PCV13) were identified. Additionally, 7.5% of the non-vaccine serotypes 6C, 9N/L, 20, 24F, 35B, and 35F, were observed. In the case of S. pneumoniae asymptomatic children carriers, the most common serogroup/types were 6B, 14, 19F, 23F, 4, 9V/A, 1, 19A, 6A, and 3 (42.7% of PCV7 serotypes, 44.2% of PCV10, and 58% of PCV13). For 6.1% of the cases co-colonization was detected. Serotypes 14, 1, 5, and 19A were more implicated in IPD (p < 0.01), whereas serotype 6A was exclusively isolated from carriers (p < 0.01). Deaths associated with IPD were related to serotypes 19A, 14, 18C, and one non-typeable isolate. Among IPD related to vaccine serotypes, the rates of penicillin non-susceptible isolates were higher in no meningitis cases (80%) than in meningitis (66.7%), with serotypes 14, 19A, 19F, and 23F presenting the highest MIC levels (>2μg/ml). Resistance to cefotaxime was higher in isolates from meningitis (40.5%); however, resistance to erythromycin and co-trimoxazole (>40%) was more pronounced in no-meningeal forms. Overall, our results showed that PCV13 conjugate vaccine would cover up to 90% of the circulating isolates associated with IPD in Algeria, highlighting the importance of monitoring the frequency of S. pneumoniae serogroups/types during pre- and post-vaccination periods. PMID:27379023

  8. MOLECULAR CHARACTERIZATION OF VIRULENCE AND ANTIMICROBIAL SUSCEPTIBILITY PROFILES OF UROPATHOGENIC ESCHERICHIA COLI FROM PATIENTS IN A TERTIARY HOSPITAL, SOUTHERN THAILAND.

    PubMed

    Themphachanal, Monchanok; Kongpheng, Suttiporn; Rattanachuay, Pattamarat; Khianngam, Saowapar; Singkhamanan, Kamonnut; Sukhumungoon, Pharanai

    2015-11-01

    Among uropathogens, uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infection (UTI) worldwide, but clinical aspects due to this bacterial species is not fully understood in southern Thailand. Two hundred fifty-four UPEC isolates from patients admitted to Maharaj Nakhon Si Thammarat Hospital, southern Thailand were examined for crucial virulence genes, showing that 33.5% contained at least one of the virulence, genes tested. Genes encoding P fimbria, cytotoxic necrotizing factor-1 and α-hemolysin constituted the majority (15.8%) carried by UPEC isolates. Phylogenetic group classification revealed that 57.5% of UPEC belonged to group D. Antimicrobial susceptibility tests showed that 70.5% and 65.1% of the isolates were resistant to ciprofloxacin and norfloxacin, respectively. Moreover, 50.0% of UPEC were capable of producing extended spectrum beta-lactamases. These findings should be of benefit for more appropriate treatment of UTI patients in this region of Thailand. Keywords: uropathogenic Escherichia coli, antibiotics resistance, cnfl, hlyA, pap, Thailand PMID:26867360

  9. Diversity and antimicrobial susceptibility profiling of staphylococci isolated from bovine mastitis cases and close human contacts.

    PubMed

    Schmidt, T; Kock, M M; Ehlers, M M

    2015-09-01

    The objectives of this study were to examine the diversity of Staphylococcus spp. recovered from bovine intramammary infections and humans working in close contact with the animals and to evaluate the susceptibility of the staphylococcal isolates to different antimicrobials. A total of 3,387 milk samples and 79 human nasal swabs were collected from 13 sampling sites in the KwaZulu-Natal province of South Africa. In total, 146 Staph. aureus isolates and 102 coagulase-negative staphylococci (CNS) were recovered from clinical and subclinical milk samples. Staphylococcusaureus was isolated from 12 (15.2%) of the human nasal swabs and 95 representative CNS were recovered for further characterization. The CNS were identified using multiplex-PCR assays, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and tuf gene sequencing. Seven Staphylococcus spp. were identified among the CNS of bovine origin, with Staph.chromogenes (78.4%) predominating. The predominant CNS species recovered from the human nasal swabs was Staph.epidermidis (80%) followed by Staph.chromogenes (6.3%). The antimicrobial susceptibility of all staphylococcal isolates was evaluated using disk diffusion and was supplemented by screening for specific antimicrobial resistance genes. Ninety-eight (67.1%) Staph.aureus isolates of bovine origin were pansusceptible; 39 (26.7%) isolates were resistant to a single class, and 7 (4.8%) isolates were resistant to 2 classes of antimicrobials. Two Staph. aureus (1.4%) isolates were multidrug-resistant. Resistance to penicillin was common, with 28.8% of the bovine and 75% of the human Staph. aureus isolates exhibiting resistance. A similar observation was made with the CNS, where 37.3% of the bovine and 89.5% of the human isolates were resistant to penicillin. Multidrug-resistance was common among the human CNS, with 39% of the isolates exhibiting resistance to 3 or more classes of antimicrobials. The antimicrobial

  10. Panton-Valentine leukocidin and some exotoxins of Staphylococcus aureus and antimicrobial susceptibility profiles of staphylococci isolated from milks of small ruminants.

    PubMed

    Ünal, Nilgün; Askar, Şinasi; Macun, Hasan Ceyhun; Sakarya, Fatma; Altun, Belgin; Yıldırım, Murat

    2012-03-01

    The aims of this study were to determine the existence of pvl gene, some toxin genes, and mecA gene in Staphylococcus aureus strains isolated from sheep milk and to examine antimicrobial resistance profiles in staphylococci from sheep and goats' milk. The milk samples were collected from 13 different small ruminant farms in Kirikkale province from February to August 2009. A total of 1,604 half-udder milk samples from 857 ewes and 66 half-udder milk samples from 33 goats were collected. Staphylococcus spp. were isolated and identified from the samples. Toxin genes and mecA gene among S. aureus strains were determined by PCR. Antimicrobial susceptibility of staphylococci was examined by the disk diffusion method on Mueller-Hinton agar, and interpreted according to the Clinical Laboratory Standards Institute (CLSI) guidelines. The prevalence of subclinical intramammary infection in both ewes and goats was 5.2%. The most prevalent subclinical mastitis agents were coagulase-negative staphylococci and S. aureus with prevalences 2.8% (n:46) and 1.3% (n = 21), respectively. The prevalence of resistances in isolated Staphylococcus spp. to penicilin G, tetracycline, erythromycin, gentamicin, and enrofloxacin were found as 26.9% (18), 7.5% (5), 6.0% (4), 3.0% (2), and 1.5% (1), respectively. Only 3 of the 21 S. aureus ewe isolates (13.4%) were shown to harbor enterotoxin genes being either seh, sej or sec. However, fourteen (66.6%) of the 21 S. aureus isolates had pvl gene while none of the isolates harbored mecA gene. In conclusion, Staphylococci were shown to be the most prevalent bacteria isolated from subclinical mastitis of ewes and goats and these isolates were susceptible to most of the antibiotics. In addition, S. aureus strains isolated from ewes were harboring few staphylococcal enterotoxin genes. However, Panton-Valentine leukocidin produced by S. aureus could be an important virulence factor and contribute to subclinical mastitis pathogenicity. PMID:21800213

  11. Differential expression profiling of miRNAs between Marek’s disease resistant and susceptible chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mounting evidence indicates microRNAs (miRNAs) play important roles in various biological processes including all aspects of cancer biology. The aim of this study was to profile and to assess the differences of miRNAs between the treatment groups of two lines of White Leghorns with or without viral ...

  12. Susceptibility profile of Aedes aegypti from Santiago Island, Cabo Verde, to insecticides.

    PubMed

    Rocha, Hélio Daniel Ribeiro; Paiva, Marcelo Henrique Santos; Silva, Norma Machado; de Araújo, Ana Paula; Camacho, Denise dos Reis da Rosa de Azevedo; Moura, Aires Januário Fernandes da; Gómez, Lara Ferrero; Ayres, Constância Flávia Junqueira; Santos, Maria Alice Varjal de Melo

    2015-12-01

    In 2009, Cabo Verde diagnosed the first dengue cases, with 21,137 cases reported and Aedes aegypti was identified as the vector. Since the outbreak, chemical insecticides and source reduction were used to control the mosquito population. This study aimed to assess the susceptibility of A. aegypti populations from Santiago, Cabo Verde to insecticides and identify the mechanisms of resistance. Samples of A. aegypti eggs were obtained at two different time periods (2012 and 2014), using ovitraps in different locations in Santiago Island to establish the parental population. F1 larvae were exposed to different concentrations of insecticides (Bacillus thuringiensis var israelensis (Bti), diflubenzuron and temephos) to estimate the lethal concentrations (LC90) and calculate the respective rate of resistance (RR90). Semi-field tests using temephos-ABATE(®) were performed to evaluate the persistence of the product. Bottle tests using female mosquitoes were carried out to determine the susceptibility to the adulticides malathion, cypermethrin and deltamethrin. Biochemical and molecular tests were performed to investigate the presence of metabolic resistance mechanisms, associated with the enzymes glutathione S-transferases (GSTs), esterases and mixed-function oxidases (MFO) and to detect mutations or alterations in the sodium channel and acetylcholinesterase genes. A. aegypti mosquitoes from Santiago exhibited resistance to deltamethrin, cypermethrin (mortality<80%) and temephos (RR90=4.4) but susceptibility to malathion (mortality≥98%), Bti and diflubenzuron. The low level of resistance to temephos did not affect the effectiveness of Abate(®). The enzymatic analysis conducted in 2012 revealed slight changes in the activities of GST (25%), MFO (18%), α-esterase (19%) and β-esterase (17%), but no significant changes in 2014. Target site resistance mutations were not detected. Our results suggest that the A. aegypti population from Santiago is resistant to two major

  13. Comparisons of protein profiles of beech bark disease resistant and susceptible American beech (Fagus grandifolia)

    PubMed Central

    2013-01-01

    Background Beech bark disease is an insect-fungus complex that damages and often kills American beech trees and has major ecological and economic impacts on forests of the northeastern United States and southeastern Canadian forests. The disease begins when exotic beech scale insects feed on the bark of trees, and is followed by infection of damaged bark tissues by one of the Neonectria species of fungi. Proteomic analysis was conducted of beech bark proteins from diseased trees and healthy trees in areas heavily infested with beech bark disease. All of the diseased trees had signs of Neonectria infection such as cankers or fruiting bodies. In previous tests reported elsewhere, all of the diseased trees were demonstrated to be susceptible to the scale insect and all of the healthy trees were demonstrated to be resistant to the scale insect. Sixteen trees were sampled from eight geographically isolated stands, the sample consisting of 10 healthy (scale-resistant) and 6 diseased/infested (scale-susceptible) trees. Results Proteins were extracted from each tree and analysed in triplicate by isoelectric focusing followed by denaturing gel electrophoresis. Gels were stained and protein spots identified and intensity quantified, then a statistical model was fit to identify significant differences between trees. A subset of BBD differential proteins were analysed by mass spectrometry and matched to known protein sequences for identification. Identified proteins had homology to stress, insect, and pathogen related proteins in other plant systems. Protein spots significantly different in diseased and healthy trees having no stand or disease-by-stand interaction effects were identified. Conclusions Further study of these proteins should help to understand processes critical to resistance to beech bark disease and to develop biomarkers for use in tree breeding programs and for the selection of resistant trees prior to or in early stages of BBD development in stands. Early

  14. Antimicrobial Susceptibility Profiles of Human Campylobacter jejuni Isolates and Association with Phylogenetic Lineages

    PubMed Central

    Cha, Wonhee; Mosci, Rebekah; Wengert, Samantha L.; Singh, Pallavi; Newton, Duane W.; Salimnia, Hossein; Lephart, Paul; Khalife, Walid; Mansfield, Linda S.; Rudrik, James T.; Manning, Shannon D.

    2016-01-01

    Campylobacter jejuni is a zoonotic pathogen and the most common bacterial cause of human gastroenteritis worldwide. With the increase of antibiotic resistance to fluoroquinolones and macrolides, the drugs of choice for treatment, C. jejuni was recently classified as a serious antimicrobial resistant threat. Here, we characterized 94 C. jejuni isolates collected from patients at four Michigan hospitals in 2011 and 2012 to determine the frequency of resistance and association with phylogenetic lineages. The prevalence of resistance to fluoroquinolones (19.1%) and macrolides (2.1%) in this subset of C. jejuni isolates from Michigan was similar to national reports. High frequencies of fluoroquinolone-resistant C. jejuni isolates, however, were recovered from patients with a history of foreign travel. A high proportion of these resistant isolates were classified as multilocus sequence type (ST)-464, a fluoroquinolone-resistant lineage that recently emerged in Europe. A significantly higher prevalence of tetracycline-resistant C. jejuni was also found in Michigan and resistant isolates were more likely to represent ST-982, which has been previously recovered from ruminants and the environment in the U.S. Notably, patients with tetracycline-resistant C. jejuni infections were more likely to have contact with cattle. These outcomes prompt the need to monitor the dissemination and diversification of imported fluoroquinolone-resistant C. jejuni strains and to investigate the molecular epidemiology of C. jejuni recovered from cattle and farm environments to guide mitigation strategies. PMID:27199922

  15. Diversity of Bipolaris species in clinical samples in the United States and their antifungal susceptibility profiles.

    PubMed

    da Cunha, K C; Sutton, D A; Fothergill, A W; Cano, J; Gené, J; Madrid, H; De Hoog, S; Crous, P W; Guarro, J

    2012-12-01

    A set of 104 isolates from human clinical samples from the United States, morphologically compatible with Bipolaris, were morphologically and molecularly identified through the sequence analysis of the internal transcribed space (ITS) region of the nuclear ribosomal DNA (rDNA). The predominant species was Bipolaris spicifera (67.3%), followed by B. hawaiiensis (18.2%), B. cynodontis (8.6%), B. micropus (2.9%), B. australiensis (2%), and B. setariae (1%). Bipolaris cynodontis, B. micropus, and B. setariae represent new records from clinical samples. The most common anatomical sites where isolates were recovered were the nasal region (30.7%), skin (19.2%), lungs (14.4%), and eyes (12.5%). The antifungal susceptibilities of 5 species of Bipolaris to 9 drugs are provided. With the exception of fluconazole and flucytosine, the antifungals tested showed good activity. PMID:23052310

  16. Diversity of Bipolaris Species in Clinical Samples in the United States and Their Antifungal Susceptibility Profiles

    PubMed Central

    da Cunha, K. C.; Sutton, D. A.; Fothergill, A. W.; Cano, J.; Madrid, H.; De Hoog, S.; Crous, P. W.; Guarro, J.

    2012-01-01

    A set of 104 isolates from human clinical samples from the United States, morphologically compatible with Bipolaris, were morphologically and molecularly identified through the sequence analysis of the internal transcribed space (ITS) region of the nuclear ribosomal DNA (rDNA). The predominant species was Bipolaris spicifera (67.3%), followed by B. hawaiiensis (18.2%), B. cynodontis (8.6%), B. micropus (2.9%), B. australiensis (2%), and B. setariae (1%). Bipolaris cynodontis, B. micropus, and B. setariae represent new records from clinical samples. The most common anatomical sites where isolates were recovered were the nasal region (30.7%), skin (19.2%), lungs (14.4%), and eyes (12.5%). The antifungal susceptibilities of 5 species of Bipolaris to 9 drugs are provided. With the exception of fluconazole and flucytosine, the antifungals tested showed good activity. PMID:23052310

  17. Distributed lags time series analysis versus linear correlation analysis (Pearson's r) in identifying the relationship between antipseudomonal antibiotic consumption and the susceptibility of Pseudomonas aeruginosa isolates in a single Intensive Care Unit of a tertiary hospital.

    PubMed

    Erdeljić, Viktorija; Francetić, Igor; Bošnjak, Zrinka; Budimir, Ana; Kalenić, Smilja; Bielen, Luka; Makar-Aušperger, Ksenija; Likić, Robert

    2011-05-01

    The relationship between antibiotic consumption and selection of resistant strains has been studied mainly by employing conventional statistical methods. A time delay in effect must be anticipated and this has rarely been taken into account in previous studies. Therefore, distributed lags time series analysis and simple linear correlation were compared in their ability to evaluate this relationship. Data on monthly antibiotic consumption for ciprofloxacin, piperacillin/tazobactam, carbapenems and cefepime as well as Pseudomonas aeruginosa susceptibility were retrospectively collected for the period April 2006 to July 2007. Using distributed lags analysis, a significant temporal relationship was identified between ciprofloxacin, meropenem and cefepime consumption and the resistance rates of P. aeruginosa isolates to these antibiotics. This effect was lagged for ciprofloxacin and cefepime [1 month (R=0.827, P=0.039) and 2 months (R=0.962, P=0.001), respectively] and was simultaneous for meropenem (lag 0, R=0.876, P=0.002). Furthermore, a significant concomitant effect of meropenem consumption on the appearance of multidrug-resistant P. aeruginosa strains (resistant to three or more representatives of classes of antibiotics) was identified (lag 0, R=0.992, P<0.001). This effect was not delayed and it was therefore identified both by distributed lags analysis and the Pearson's correlation coefficient. Correlation coefficient analysis was not able to identify relationships between antibiotic consumption and bacterial resistance when the effect was delayed. These results indicate that the use of diverse statistical methods can yield significantly different results, thus leading to the introduction of possibly inappropriate infection control measures. PMID:21277747

  18. Evaluation of bacteriological profile and antibiotic sensitivity patterns in children with urinary tract infection: A prospective study from a tertiary care center

    PubMed Central

    Badhan, Ranjana; Singh, Dig Vijay; Badhan, Lashkari R.; Kaur, Anureet

    2016-01-01

    Introduction: Development of regional surveillance programs is necessary for the development of community-acquired urinary tract infection (UTI) guidelines, especially for sub-urban and rural areas where empirical treatment is the mainstay in the absence of proper diagnostic modalities. Our aim was to evaluate the bacteriological profile and antibiotic sensitivity patterns in children with UTI prospectively from a tertiary care center. Methods: A total of 800 children up to 18 years of age with suspected UTI attending our center were included. For all suspected cases urine microscopy, gram staining, and culture were done. Antibiotic sensitivity was performed on selected antimicrobials using disk diffusion method following Clinical Laboratory Standards Institute guidelines. Results: Majority of pathogens were isolated from female (54.2%) patients. Pre-teens (52.1%) and teens (27.1%) were most commonly affected age group. The most common presentation in culture-proven UTI was fever with urinary symptoms (33.3%). In a group of 192 patients 26.7% had proven UTI. Escherichia coli (42.3%) was the most common aetiological agent, followed by Enterococcus fecalis (13.5%), Klebsiella spp. (11.5%) and Staphylococcus aureus (11.5%). Most active antibiotics against Gram-negative isolates were nitrofurantoin, cefotaxime, and amikacin. Gram-positive isolates were sensitive to nitrofurantoin, cotrimoxazole, and novobiocin. Conclusion: E. coli was the commonest isolate. The organisms grown in significant numbers were E. fecalis, Klebsiella spp. and S. aureus, causing UTI in 0–18 years of age group. Gram-negative isolates were sensitive to nitrofurantoin, amikacin, and cefotaxime. Gram-positive isolates were sensitive to nitrofurantoin, cotrimoxazole, and novobiocin. Prospective, regional studies are ensured periodically to explain bacteriological profile and antibiotic sensitivity patterns to be applicable for children with UTI over that geographic area. PMID:26941495

  19. Can carbapenem-resistant enterobacteriaceae susceptibility results obtained from surveillance cultures predict the susceptibility of a clinical carbapenem-resistant enterobacteriaceae?

    PubMed

    Perez, Leandro Reus Rodrigues; Rodrigues, Diógenes; Dias, Cícero

    2016-08-01

    We evaluated the susceptibility profile of a colonizing carbapenem-resistant enterobacteriaceae to predict its susceptibility when recovered from a clinical specimen. An overall agreement of 88.7% (517 out of 583; 95% confidence interval, 85.8%-91.0%) was observed for the combinations of 11 antibiotics with 53 pairs of Klebsiella pneumoniae carbapenemase-producing K pneumoniae (the only carbapenem-resistant enterobacteriaceae detected). Very major errors were observed mainly for aminoglycoside agents and colistin, limiting the predictability of the susceptibility profile for these clinical isolates. PMID:27021509

  20. Correlation between biofilm production, antibiotic susceptibility and exopolysaccharide composition in Burkholderia pseudomallei bpsI, ppk, and rpoS mutant strains.

    PubMed

    Mongkolrob, Rungrawee; Taweechaisupapong, Suwimol; Tungpradabkul, Sumalee

    2015-11-01

    Burkholderia pseudomallei is the cause of melioidosis, a fatal tropical infectious disease, which has been reported to have a high rate of recurrence, even when an intensive dose of antibiotics is used. Biofilm formation is believed to be one of the possible causes of relapse because of its ability to increase drug resistance. EPS in biofilms have been reported to be related to the limitation of antibiotic penetration in B. pseudomallei. However, the mechanisms by which biofilms restrict the diffusion of antibiotics remain unclear. The present study presents a correlation between exopolysaccharide production in biofilm matrix and antibiotic resistance in B. pseudomallei using bpsI, ppk, and rpoS mutant strains. CLSM revealed a reduction in exopolysaccharide production and disabled micro-colony formation in B. pseudomallei mutants, which paralleled the antibiotic resistance. Different ratios of carbohydrate contents in the exopolysaccharides of the mutants were detected, although they have the same components, including glucose, galactose, mannose, and rhamnose, with the exception being that no detectable rhamnose peak was observed in the bpsI mutant. These results indicate that the correlation between these phenomena in the B. pseudomallei biofilm at least results from the exopolysaccharide, which may be under the regulation of bpsI, ppk, or rpoS genes. PMID:26486518

  1. Susceptibility profile and epidemiological cut-off values of Cryptococcus neoformans species complex from Argentina.

    PubMed

    Córdoba, Susana; Isla, Maria G; Szusz, Wanda; Vivot, Walter; Altamirano, Rodrigo; Davel, Graciela

    2016-06-01

    Epidemiological cut-off values (ECVs) based on minimal inhibitory concentration (MIC) distribution have been recently proposed for some antifungal drug/Cryptococcus neoformans combinations. However, these ECVs vary according to the species studied, being serotypes and the geographical origin of strains, variables to be considered. The aims were to define the wild-type (WT) population of the C. neoformans species complex (C. neoformans) isolated from patients living in Argentina, and to propose ECVs for six antifungal drugs. A total of 707 unique C. neoformans isolates obtained from HIV patients suffering cryptococcal meningitis were studied. The MIC of amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole and posaconazole was determined according to the EDef 7.2 (EUCAST) reference document. The MIC distribution, MIC50 , MIC90 and ECV for each of these drugs were calculated. The highest ECV, which included ≥95% of the WT population modelled, was observed for flucytosine and fluconazole (32 μg ml(-1) each). For amphotericin B, itraconazole, voriconazole and posaconazole, the ECVs were: 0.5, 0.5, 0.5 and 0.06 μg ml(-1) respectively. The ECVs determined in this study may aid in identifying the C. neoformans strains circulating in Argentina with decreased susceptibility to the antifungal drugs tested. PMID:26865081

  2. Whole metagenome profiling reveals skin microbiome-dependent susceptibility to atopic dermatitis flare.

    PubMed

    Chng, Kern Rei; Tay, Angeline Su Ling; Li, Chenhao; Ng, Amanda Hui Qi; Wang, Jingjing; Suri, Bani Kaur; Matta, Sri Anusha; McGovern, Naomi; Janela, Baptiste; Wong, Xuan Fei Colin C; Sio, Yang Yie; Au, Bijin Veonice; Wilm, Andreas; De Sessions, Paola Florez; Lim, Thiam Chye; Tang, Mark Boon Yang; Ginhoux, Florent; Connolly, John E; Lane, E Birgitte; Chew, Fook Tim; Common, John E A; Nagarajan, Niranjan

    2016-01-01

    Whole metagenome analysis has the potential to reveal functional triggers of skin diseases, but issues of cost, robustness and sampling efficacy have limited its application. Here, we have established an alternative, clinically practical and robust metagenomic analysis protocol and applied it to 80 skin microbiome samples epidemiologically stratified for atopic dermatitis (AD). We have identified distinct non-flare, baseline skin microbiome signatures enriched for Streptococcus and Gemella but depleted for Dermacoccus in AD-prone versus normal healthy skin. Bacterial challenge assays using keratinocytes and monocyte-derived dendritic cells established distinct IL-1-mediated, innate and Th1-mediated adaptive immune responses with Staphylococcus aureus and Staphylococcus epidermidis. Bacterial differences were complemented by perturbations in the eukaryotic community and functional shifts in the microbiome-wide gene repertoire, which could exacerbate a dry and alkaline phenotype primed for pathogen growth and inflammation in AD-susceptible skin. These findings provide insights into how the skin microbial community, skin surface microenvironment and immune system cross-modulate each other, escalating the destructive feedback cycle between them that leads to AD flare. PMID:27562258

  3. Transcriptome profiling of resistant and susceptible Cavendish banana roots following inoculation with Fusarium oxysporum f. sp. cubense tropical race 4

    PubMed Central

    2012-01-01

    Background Fusarium wilt, caused by the fungal pathogen Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), is considered the most lethal disease of Cavendish bananas in the world. The disease can be managed in the field by planting resistant Cavendish plants generated by somaclonal variation. However, little information is available on the genetic basis of plant resistance to Foc TR4. To a better understand the defense response of resistant banana plants to the Fusarium wilt pathogen, the transcriptome profiles in roots of resistant and susceptible Cavendish banana challenged with Foc TR4 were compared. Results RNA-seq analysis generated more than 103 million 90-bp clean pair end (PE) reads, which were assembled into 88,161 unigenes (mean size = 554 bp). Based on sequence similarity searches, 61,706 (69.99%) genes were identified, among which 21,273 and 50,410 unigenes were assigned to gene ontology (GO) categories and clusters of orthologous groups (COG), respectively. Searches in the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG) mapped 33,243 (37.71%) unigenes to 119 KEGG pathways. A total of 5,008 genes were assigned to plant-pathogen interactions, including disease defense and signal transduction. Digital gene expression (DGE) analysis revealed large differences in the transcriptome profiles of the Foc TR4-resistant somaclonal variant and its susceptible wild-type. Expression patterns of genes involved in pathogen-associated molecular pattern (PAMP) recognition, activation of effector-triggered immunity (ETI), ion influx, and biosynthesis of hormones as well as pathogenesis-related (PR) genes, transcription factors, signaling/regulatory genes, cell wall modification genes and genes with other functions were analyzed and compared. The results indicated that basal defense mechanisms are involved in the recognition of PAMPs, and that high levels of defense-related transcripts may contribute to Foc TR4 resistance in banana

  4. Differential Gene Expression Profile in the Rat Caudal Vestibular Nucleus is Associated with Individual Differences in Motion Sickness Susceptibility

    PubMed Central

    Zhou, Wei; Tang, Yi-Fan; Pan, Lei-Lei; Cai, Yi-Ling

    2015-01-01

    Objective To identify differentially expressed genes associated with motion sickness (MS) susceptibility in the rat caudal vestibular nucleus. Methods We identified MS susceptible (MSS) and insusceptible (inMSS) rats by quantifying rotation-induced MS symptoms: defecation and spontaneous locomotion activity. Microarray analysis was used to screen differentially expressed genes in the caudal vestibular nucleus (CVN) after rotation. Plasma stress hormones were identified by radioimmunoassay. Candidate genes were selected by bioinformatics analysis and the microarray results were verified by real-time quantitative-PCR (RT-qPCR) methods. By using Elvax implantation, receptor antagonists or recombinant adenovirus targeting the candidate genes were applied to the CVN to evaluate their contribution to MS susceptibility variability. Validity of gene expression manipulation was verified by RT-qPCR and western blot analysis. Results A total of 304 transcripts were differentially expressed in the MSS group compared with the inMSS group. RT-qPCR analysis verified the expression pattern of candidate genes, including nicotinic cholinergic receptor (nAchR) α3 subunit, 5-hydroxytryptamine receptor 4 (5-HT4R), tachykinin neurokinin-1 (NK1R), γ-aminobutyric acid A receptor (GABAAR) α6 subunit, olfactory receptor 81 (Olr81) and homology 2 domain-containing transforming protein 1 (Shc1). In MSS animals, the nAchR antagonist mecamylamine significantly alleviated rotation-induced MS symptoms and the plasma β-endorphin response. The NK1R antagonist CP99994 and Olr81 knock-down were effective for the defecation response, while the 5-HT4R antagonist RS39604 and Shc1 over-expression showed no therapeutic effect. In inMSS animals, rotation-induced changes in spontaneous locomotion activity and the plasma β-endorphin level occurred in the presence of the GABAAR antagonist gabazine. Conclusion Our findings suggested that the variability of the CVN gene expression profile after motion

  5. Immunological profile of resistance and susceptibility in naturally infected dogs by Leishmania infantum.

    PubMed

    de Almeida Leal, Gleisiane Gomes; Roatt, Bruno Mendes; de Oliveira Aguiar-Soares, Rodrigo Dian; Carneiro, Cláudia Martins; Giunchetti, Rodolfo Cordeiro; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; Francisco, Amanda Fortes; Cardoso, Jamille Mirelle; Mathias, Fernando Augusto Siqueira; Correa-Oliveira, Rodrigo; Carneiro, Mariângela; Coura-Vital, Wendel; Reis, Alexandre Barbosa

    2014-10-15

    Visceral leishmaniasis has a great impact on public health, and dogs are considered the main domestic reservoir of Leishmania infantum, the causal parasite. In this study, 159 animals naturally infected by L. infantum from an endemic area of Brazil were evaluated through an analysis of cellular responses, using flow cytometry, and of the hematological parameters. The results confirmed that disease progression is associated with anemia and reductions in eosinophils, monocytes and lymphocytes. The investigation of the immune response, based on the immunophenotypic profile of peripheral blood, showed declines in the absolute numbers of T lymphocytes CD5(+) and their subsets (CD4(+) and CD8(+)) and a drop of B lymphocytes in asymptomatic seropositive (AD-II) and symptomatic seropositive (SD) dogs. Neutrophils, when stimulated with soluble antigen of L. infantum, showed higher synthesis of interferon (IFN)-γ(+) in AD-II and SD groups, with decreased production of interleukin (IL)-4(+) in asymptomatic seronegative dogs positive for L. infantum infection based on polymerase chain reaction testing (AD-I group). In the AD-II and SD groups, subpopulations of stimulated lymphocytes (CD4(+) and CD8(+)) also exhibited greater synthesis of IFN-γ(+) and IL-4(+) in culture. These results suggest that the animals of the AD-II and SD groups exhibited a mixed immune response (Type 1 and 2) and the AD-I group presenting an immune profile very similar to normal control animals. PMID:25234767

  6. Antibiotic Resistance, Virulence Gene, and Molecular Profiles of Shiga Toxin-Producing Escherichia coli Isolates from Diverse Sources in Calcutta, India

    PubMed Central

    Khan, Asis; Das, S. C.; Ramamurthy, T.; Sikdar, A.; Khanam, J.; Yamasaki, S.; Takeda, Y.; Nair, G. Balakrish

    2002-01-01

    Antibiotic resistance, virulence gene, and molecular profiles of Shiga toxin-producing Escherichia coli (STEC) non-O157 strains isolated from human stool samples, cow stool samples, and beef samples over a period of 2 years in Calcutta, India, were determined. Resistance to one or more antibiotics was observed in 49.2% of the STEC strains, with some of the strains exhibiting multidrug resistance. The dominant combinations of virulence genes present in the strains studied were stx1 and stx2 (44.5% of strains) and stx1, stx2, and hlyA (enterohemorrhagic E. coli hemolysin gene) (19% of strains). Only 6.4% of the STEC strains harbored eae. The diversity of STEC strains from various sources was assessed by random amplification of polymorphic DNA (RAPD). STEC strains that gave identical or nearly similar DNA fingerprints in RAPD-PCR and had similar virulence genotypes were further characterized by pulsed-field gel electrophoresis (PFGE). Identical RAPD and PFGE profiles were observed in four sets of strains, with each set comprising two strains. There was no match in the RAPD and PFGE profiles between strains of STEC isolated from cows and those isolated from humans. It appears that the clones present in bovine sources are not transmitted to humans in the Calcutta setting although these strains showed evolutionary relatedness. Maybe for this reason, STEC has still not become a major problem in India. PMID:12037056

  7. In Vitro Activity of Polymyxin B in Combination with Various Antibiotics against Extensively Drug-Resistant Enterobacter cloacae with Decreased Susceptibility to Polymyxin B.

    PubMed

    Cai, Yiying; Lim, Tze-Peng; Teo, Jocelyn; Sasikala, Suranthran; Lee, Winnie; Hong, Yanjun; Chan, Eric Chun Yong; Tan, Thean Yen; Tan, Thuan-Tong; Koh, Tse Hsien; Hsu, Li Yang; Kwa, Andrea L

    2016-09-01

    Against extensively drug-resistant (XDR) Enterobacter cloacae, combination antibiotic therapy may be the only option. We investigated the activity of various antibiotics in combination with polymyxin B using time-kill studies (TKS). TKS were conducted with four nonclonal XDR E. cloacae isolates with 5 log10 CFU/ml bacteria against maximum, clinically achievable concentrations of polymyxin B alone and in two-drug combinations with 10 different antibiotics. A hollow-fiber infection model (HFIM) simulating clinically relevant polymyxin B and tigecycline dosing regimens was conducted for two isolates over 240 h. Emergence of resistance was quantified using antibiotic-containing (3× MIC) media. Biofitness and stability of resistant phenotypes were determined. All XDR E. cloacae isolates were resistant to all antibiotics except for polymyxin B (polymyxin B MIC, 1 to 4 mg/liter). All isolates harbored metallo-β-lactamases (two with NDM-1, two with IMP-1). In single TKS, all antibiotics alone demonstrated regrowth at 24 h, except amikacin against two strains and polymyxin B and meropenem against one strain each. In combination TKS, only polymyxin B plus tigecycline was bactericidal against all four XDR E. cloacae isolates at 24 h. In HFIM, tigecycline and polymyxin B alone did not exhibit any killing activity. Bactericidal kill was observed at 24 h for both isolates for polymyxin B plus tigecycline; killing was sustained for one isolate but regrowth was observed for the second. Phenotypically stable resistant mutants with reduced in vitro growth rates were observed. Polymyxin B plus tigecycline is a promising combination against XDR E. cloacae However, prolonged and indiscriminate use can result in resistance emergence. PMID:27324776

  8. Antibiotic Resistance

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Antibiotic Resistance Share Tweet Linkedin Pin it More sharing options ... these products really help. To Learn More about Antibiotic Resistance Get Smart About Antibiotics (Video) Fact Sheets and ...

  9. Aquaculture changes the profile of antibiotic resistance and mobile genetic element associated genes in Baltic Sea sediments.

    PubMed

    Muziasari, Windi I; Pärnänen, Katariina; Johnson, Timothy A; Lyra, Christina; Karkman, Antti; Stedtfeld, Robert D; Tamminen, Manu; Tiedje, James M; Virta, Marko

    2016-04-01

    Antibiotics are commonly used in aquaculture and they can change the environmental resistome by increasing antibiotic resistance genes (ARGs). Sediment samples were collected from two fish farms located in the Northern Baltic Sea, Finland, and from a site outside the farms (control). The sediment resistome was assessed by using a highly parallel qPCR array containing 295 primer sets to detect ARGs, mobile genetic elements and the 16S rRNA gene. The fish farm resistomes were enriched in transposon and integron associated genes and in ARGs encoding resistance to antibiotics which had been used to treat fish at the farms. Aminoglycoside resistance genes were also enriched in the farm sediments despite the farms not having used aminoglycosides. In contrast, the total relative abundance values of ARGs were higher in the control sediment resistome and they were mainly genes encoding efflux pumps followed by beta-lactam resistance genes, which are found intrinsically in many bacteria. This suggests that there is a natural Baltic sediment resistome. The resistome associated with fish farms can be from native ARGs enriched by antibiotic use at the farms and/or from ARGs and mobile elements that have been introduced by fish farming. PMID:26976842

  10. High diversity of bacterial pathogens and antibiotic resistance in salmonid fish farm pond water as determined by molecular identification employing 16S rDNA PCR, gene sequencing and total antibiotic susceptibility techniques.

    PubMed

    Moore, John E; Huang, Junhua; Yu, Pengbo; Ma, Chaofeng; Moore, Peter Ja; Millar, Beverley C; Goldsmith, Colin E; Xu, Jiru

    2014-10-01

    The aim of this study was to examine the microbiological and related parameters (antibiotic resistance and pathogen identification) of water at two salmonid fish farms in Northern Ireland. Total Bacterial Counts at the Movanagher Fish Farm was 1730 colony forming units (cfu)/ml water (log10 3.24cfu/ml) and 3260cfu/ml (log10 3.51cfu/ml) at the Bushmills Salmon Station. Examination of resulting organisms revealed 10 morphological phenotypes, which were subsequently sequenced to determine their identification. All these organisms were Gram-negative and no Gram-positive organisms were isolated from any water sample. From these phenotypes, eight different genera were identified including Acinetobacter, Aeromonas, Chryseobacterium, Erwinia, Flavobacterium, Pseudomonas and Rheinheimera. One unnamed novel taxon was identified from water at the Movanagher Fish Farm, belonging to the genus Acinetobacter and has been tentatively named Acinetobacter movanagherensis. No other novel taxa were observed. All but one of these environmental organisms (Erwinia) are potential pathogens of fish disease. Total antibiotic resistance was observed to varying degrees in water specimens. The most resistant populations were observed in water taken from the Bushmills Salmon Station inlet, followed by water from the Movanagher Fish Farm. No resistance was observed against tetracycline and there was only one occurrence of resistance against ciprofloxacin. Overall, this study indicates that potential fish pathogens made up the majority of environmental organisms identified, even in the absence of recorded fish disease. There was also relatively high levels of total antibiotic resistance in the bacterial water populations examined, where tetracycline was the only antibiotic with zero resistance. These data indicate that the threat of bacterial disease is relatively close due to the indigenous colonization of farm water and that husbandry standards should be maintained at a high standard to avert

  11. Phenotypic and molecular antibiotic resistance profile of Enterococcus faecalis and Enterococcus faecium isolated from different traditional fermented foods.

    PubMed

    Sánchez Valenzuela, Antonio; Lavilla Lerma, Leyre; Benomar, Nabil; Gálvez, Antonio; Pérez Pulido, Rubén; Abriouel, Hikmate

    2013-02-01

    A collection of 55 enterococci (41 Enterococcus faecium and 14 E. faecalis strains) isolated from various traditional fermented foodstuffs of both animal and vegetable origins, and water was evaluated for resistance against 15 antibiotics. Lower incidence of resistance was observed with gentamicin, ampicillin, penicillin and teicoplanin. However, a high incidence of antibiotic resistance was detected for rifampicin (12 out of 14 of isolates), ciprofloxacin (9/14), and quinupristin/dalfopristin (8/14) in E. faecalis strains. Enterococcus faecium isolates were resistant to rifampicin (25/41), ciprofloxacin (23/41), erythromycin (18/41), levofloxacin (16/41), and nitrofurantoin (15/41). One Enterococcus faecalis and two E. faecium strains were resistant to vancomycin (MIC>16 μg/mL). Among 55 isolates, 27 (19 E. faecium and eight E. faecalis) were resistant to at least three antibiotics. High level of multidrug resistance to clinically important antibiotics was detected in E. faecalis strains (57% of E. faecalis versus 46% of E. faecium), which showed resistance to six to seven antibiotics, especially those isolated from foods of animal origin. So, it is necessary to re-evaluate the use of therapeutic antibiotics in stock farms at both regional and international levels due to the high number of multiple resistant (MR) bacteria. Fifty-six MR E. faecalis and E. faecium strains selected from this and previous studies (Valenzuela et al., 2008, 2010) were screened by polymerase chain reaction for antibiotic resistance genes, revealing the presence of tet(L), tet(M), ermB, cat, efrA, efrB, mphA, or msrA/B genes. The ABC Multidrug Efflux Pump EfrAB was detected in 96% of E. faecalis strains and also in 13% of E. faecium strains; this is the first report describing EfrAB in this enterococcal species. The efflux pump-associated msrA/B gene was detected in 66.66% of E. faecium strains, but not in E. faecalis strains. PMID:23259502

  12. In vitro antimicrobial susceptibility of Mycoplasma bovis isolated in Israel from local and imported cattle.

    PubMed

    Gerchman, Irena; Levisohn, Sharon; Mikula, Inna; Lysnyansky, Inna

    2009-06-12

    Monitoring of susceptibility to antibiotics in field isolates of pathogenic bovine mycoplasmas is important for appropriate choice of treatment. Our study compared in vitro susceptibility profiles of Mycoplasma bovis clinical strains, isolated during 2005-2007 from Israeli and imported calves. Minimal inhibitory concentration (MIC) values were determined for macrolides by the microbroth dilution test, for aminoglycosides by commercial Etest, and for fluoroquinolones and tetracyclines by both methods. Notably, although correlation between the methods was generally good, it was not possible to determine the MIC endpoint for enrofloxacin-resistant strains (MIC > or =2.5 microg/ml in the microtest) by Etest. Comparison of antibiotic susceptibility profiles between local and imported M. bovis strains revealed that local strains were significantly more resistant to macrolides than most isolates from imported animals, with MIC(50) of 128 microg/ml vs. 2 microg/ml for tilmicosin and 8 microg/ml vs. 1 microg/ml for tylosin, respectively. However, local strains were more susceptible than most imported strains to fluoroquinolones and spectinomycin. Difference in susceptibility to tetracycline, doxycycline and oxytetracycline between local and imported strains was expressed in MIC(90) values for imported strains in the susceptible range compared to intermediate susceptibility for local strains. The marked difference in susceptibility profiles of M. bovis strains isolated from different geographical regions seen in this study emphasizes the necessity for performing of the antimicrobial susceptibility testing periodically and on a regional basis. PMID:19250777

  13. Shifts in the Antibiotic Susceptibility, Serogroups, and Clonal Complexes of Neisseria meningitidis in Shanghai, China: A Time Trend Analysis of the Pre-Quinolone and Quinolone Eras

    PubMed Central

    Wang, Ye; Zou, Ying; Wang, Gangyi; Zhang, Xi; Xu, Xiaogang; Zhao, Miao; Hu, Fupin; Qu, Di; Chen, Min; Wang, Minggui

    2015-01-01

    Background Fluoroquinolones have been used broadly since the end of the 1980s and have been recommended for Neisseria meningitidis prophylaxis since 2005 in China. The aim of this study was to determine whether and how N. meningitidis antimicrobial susceptibility, serogroup prevalence, and clonal complex (CC) prevalence shifted in association with the introduction and expanding use of quinolones in Shanghai, a region with a traditionally high incidence of invasive disease due to N. meningitidis. Methods and Findings A total of 374 N. meningitidis isolates collected by the Shanghai Municipal Center for Disease Control and Prevention between 1965 and 2013 were studied. Shifts in the serogroups and CCs were observed, from predominantly serogroup A CC5 (84%) in 1965–1973 to serogroup A CC1 (58%) in 1974–1985, then to serogroup C or B CC4821 (62%) in 2005–2013. The rates of ciprofloxacin nonsusceptibility in N. meningitidis disease isolates increased from 0% in 1965–1985 to 84% (31/37) in 2005–2013 (p < 0.001). Among the ciprofloxacin-nonsusceptible isolates, 87% (27/31) were assigned to either CC4821 (n = 20) or CC5 (n = 7). The two predominant ciprofloxacin-resistant clones were designated ChinaCC4821-R1-C/B and ChinaCC5-R14-A. The ChinaCC4821-R1-C/B clone acquired ciprofloxacin resistance by a point mutation, and was present in 52% (16/31) of the ciprofloxacin-nonsusceptible disease isolates. The ChinaCC5-R14-A clone acquired ciprofloxacin resistance by horizontal gene transfer, and was found in 23% (7/31) of the ciprofloxacin-nonsusceptible disease isolates. The ciprofloxacin nonsusceptibility rate was 47% (7/15) among isolates from asymptomatic carriers, and nonsusceptibility was associated with diverse multi-locus sequence typing profiles and pulsed-field gel electrophoresis patterns. As detected after 2005, ciprofloxacin-nonsusceptible strains were shared between some of the patients and their close contacts. A limitation of this study is that isolates

  14. Efficacy of ultraviolet C light at sublethal dose in combination with antistaphylococcal antibiotics to disinfect catheter biofilms of methicillin-susceptible and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis in vitro

    PubMed Central

    El-Azizi, Mohamed; Khardori, Nancy

    2016-01-01

    Background Biofilm formation inside inserted medical devices leads to their failure and acts as a source of refractory infections. The ultraviolet C (UVC) light is a potential therapy that can be used against the biofilm of bacterial pathogens. Objective We evaluated the efficacy of sublethal dose of UVC light with anti-staphylococcal antibiotics against biofilms made from 30 isolates of methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus and S. epidermidis on vascular catheters. Materials and methods A novel biofilm device was used to assess the combined approach. The biofilms on the catheters were irradiated with the UVC light at 254 nm and irradiance of 6.4 mW followed by treatment with vancomycin or quinupristin/dalfopristin at twice their minimum bactericidal concentrations or with linezolid at 64 µg/mL for 24 hours. The catheters were cut into segments and sonicated, and the number of the sessile cells was determined colorimetrically using XTT viable cells assay. The effect of UVC radiation followed by treatment with an antistaphylococcal antibiotic on the viability of the bacteria in the biofilm was visualized using LIVE/DEAD BacLight bacterial viability stain and confocal laser scanning microscopy. Results Exposure of the bacterial biofilms to the UVC light or each of the antibiotics alone was ineffective in killing the bacteria. Treatment of the biofilms with the antibiotics following their exposure to UVC light significantly (P<0.001) reduced the number of viable cells within the biofilms but did not completely eradicate them. Conclusion To our knowledge, this combinatorial approach has not been investigated before. The combined approach can be used as a therapeutic modality for managing biofilm-associated infections by preventing the establishment of biofilms and/or disrupting the formed biofilms on the inserted medical devices with the goal of increasing their usefulness and preventing infectious complications. Further

  15. Socioeconomic Differences in the Risk Profiles of Susceptibility and Ever Use of Tobacco Among Indian Urban Youth: A Latent Class Approach

    PubMed Central

    2014-01-01

    Purpose: To empirically determine the socioeconomic differences in risk profiles of susceptibility and ever use of tobacco among adolescents in India and to investigate the association between the risk profiles and the psychosocial factors for tobacco use. Methods: Students in 16 private (higher socioeconomic status [SES]; n = 4,489) and 16 government (lower SES; n = 7,153) schools in two large cities in India were surveyed about their tobacco use and related psychosocial factors in 2004. Latent class analysis was used to identify homogenous, mutually exclusive typologies existing within the data. Results: Overall, 3 and 4 latent classes of susceptibility and ever use of tobacco best described students in higher- and lower- SES schools, respectively. Profiles with various combinations of susceptibility and ever use of tobacco were differentially related to psychosocial factors, with lower- SES students being more vulnerable to increased levels of tobacco use than higher- SES students. Conclusions: Acknowledging the multiple dimensions of tobacco use behaviors and identifying constellations of risk behaviors will enable more accurate understanding of etiological processes and will provide information for refining and targeting preventive interventions. Additionally, identifying the socioeconomic differences in susceptibility and ever use risk profiles and their psychosocial correlates will enable policy makers to address these inequities through improved allocation of resources. PMID:24271966

  16. Antibiotic Resistance

    MedlinePlus

    Antibiotics are medicines that fight bacterial infections. Used properly, they can save lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able to resist the effects of an antibiotic. Using antibiotics can lead to resistance. ...

  17. In vitro susceptibility of Escherichia coli strains isolated from urine samples obtained in mainland China to fosfomycin trometamol and other antibiotics: a 9-year surveillance study (2004–2012)

    PubMed Central

    2014-01-01

    Background As a result of extensive use of fluroquinlones and cephalosporins, urinary tract pathogens producing extended-spectrum beta-lactamase (ESBL) pose a considerable clinical challenge in the treatment of UTIs. In the present study we retrospectively assessed the susceptibility of E. coli strains to fosfomycin trometamol and other antibiotics commonly used for the treatment of such infections. Methods A total of 908 nonreplicate clinical E. coli urinary isolates were collected from 20 Chinese hospitals over four consecutive 1-year periods between October 2004 and June 2012. Susceptibility to antimicrobial agents fosfomycin trometamol, piperacillin-tazobactam, cefuroxime, cefotaxime, cefepime, imipenem, amikacin, levofloxacin, and nitrofurantoin was determined using the agar dilution method. A reference strain E. coli (ATCC 25922) was used as a positive control. Results were analyzed using Chi-square test or Fisher’s exact tests. Results Fosfomycin trometamol, piperacillin-tazobactam, amikacin, and imipenem were consistently the most active agents against most of the isolates. There was a decline in susceptibility to cefuroxime, cefotaxime, and cefepime between 2004 and 2010. We showed that 528 of the 908 E. coli isolates (58.1%) produced ESBLs. The ESBL-positive rates increased from 41.7% in 2004−2005 to 60.9% in 2011−2012. ESBL-producing E. coli isolates showed significantly higher resistance rates to levofloxacin than the ESBL-negative isolates. Fosfomycin trometamol, piperacillin-tazobactam, amikacin, and imipenem had good activity against both levofloxacin-susceptible and levofloxacin- nonsusceptible isolates (sensitivity rate > 90%). However susceptibility of levofloxacin-resistant isolates to cefuroxime, cefotaxime, cefepime, amikacin, and nitrofurantoin was significantly lower than that of levofloxacin-susceptible isolates. Conclusions Owing to the increase in the bacterial resistance across the world, the European Urology Association has

  18. Conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans: influence of growth conditions and antifungal susceptibility profiles.

    PubMed

    Mello, Thaís Pereira de; Aor, Ana Carolina; Oliveira, Simone Santiago Carvalho de; Branquinha, Marta Helena; Santos, André Luis Souza Dos

    2016-06-27

    In the present study, we have investigated some growth conditions capable of inducing the conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans. Germination in Sabouraud medium (pH 7.0, 37ºC, 5% CO2) showed to be a typically time-dependent event, reaching ~75% in S. minutisporum and > 90% in S. apiospermum, S. aurantiacum and L. prolificans after 4 h. Similar germination rate was observed when conidia were incubated under different media and pHs. Contrarily, temperature and CO2 tension modulated the germination. The isotropic conidial growth (swelling) and germ tube-like projection were evidenced by microscopy and cytometry. Morphometric parameters augmented in a time-dependent fashion, evidencing changes in size and granularity of fungal cells compared with dormant 0 h conidia. In parallel, a clear increase in the mitochondrial activity was measured during the transformation of conidia-into-germinated conidia. Susceptibility profiles to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin varied regarding each morphotype and each fungal species. Overall, the minimal inhibitory concentrations for hyphae were higher than conidia and germinated conidia, except for caspofungin. Collectively, our study add new data about the conidia-into-hyphae transformation in Scedosporium and Lomentospora species, which is a relevant biological process of these molds directly connected to their antifungal resistance and pathogenicity mechanisms. PMID:27355215

  19. Conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans: influence of growth conditions and antifungal susceptibility profiles

    PubMed Central

    de Mello, Thaís Pereira; Aor, Ana Carolina; de Oliveira, Simone Santiago Carvalho; Branquinha, Marta Helena; dos Santos, André Luis Souza

    2016-01-01

    In the present study, we have investigated some growth conditions capable of inducing the conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans. Germination in Sabouraud medium (pH 7.0, 37ºC, 5% CO2) showed to be a typically time-dependent event, reaching ~75% in S. minutisporum and > 90% in S. apiospermum, S. aurantiacum and L. prolificans after 4 h. Similar germination rate was observed when conidia were incubated under different media and pHs. Contrarily, temperature and CO2 tension modulated the germination. The isotropic conidial growth (swelling) and germ tube-like projection were evidenced by microscopy and cytometry. Morphometric parameters augmented in a time-dependent fashion, evidencing changes in size and granularity of fungal cells compared with dormant 0 h conidia. In parallel, a clear increase in the mitochondrial activity was measured during the transformation of conidia-into-germinated conidia. Susceptibility profiles to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin varied regarding each morphotype and each fungal species. Overall, the minimal inhibitory concentrations for hyphae were higher than conidia and germinated conidia, except for caspofungin. Collectively, our study add new data about the conidia-into-hyphae transformation in Scedosporium and Lomentospora species, which is a relevant biological process of these molds directly connected to their antifungal resistance and pathogenicity mechanisms. PMID:27355215

  20. Detection of Salmonella spp. with the BACTEC 9240 Automated Blood Culture System in 2008 - 2014 in Southern Iran (Shiraz): Biogrouping, MIC, and Antimicrobial Susceptibility Profiles of Isolates

    PubMed Central

    Anvarinejad, Mojtaba; Pouladfar, Gholam Reza; Pourabbas, Bahman; Amin Shahidi, Maneli; Rafaatpour, Noroddin; Dehyadegari, Mohammad Ali; Abbasi, Pejman; Mardaneh, Jalal

    2016-01-01

    Background Human salmonellosis continues to be a major international problem, in terms of both morbidity and economic losses. The antibiotic resistance of Salmonella is an increasing public health emergency, since infections from resistant bacteria are more difficult and costly to treat. Objectives The aims of the present study were to investigate the isolation of Salmonella spp. with the BACTEC automated system from blood samples during 2008 - 2014 in southern Iran (Shiraz). Detection of subspecies, biogrouping, and antimicrobial susceptibility testing by the disc diffusion and agar dilution methods were performed. Patients and Methods A total of 19 Salmonella spp. were consecutively isolated using BACTEC from blood samples of patients between 2008 and 2014 in Shiraz, Iran. The isolates were identified as Salmonella, based on biochemical tests embedded in the API-20E system. In order to characterize the biogroups and subspecies, biochemical testing was performed. Susceptibility testing (disc diffusion and agar dilution) and extended-spectrum β-lactamase (ESBL) detection were performed according to the clinical and laboratory standards institute (CLSI) guidelines. Results Of the total 19 Salmonella spp. isolates recovered by the BACTEC automated system, all belonged to the Salmonella enterica subsp. houtenae. Five isolates (26.5%) were resistant to azithromycin. Six (31.5%) isolates with the disc diffusion method and five (26.3%) with the agar dilution method displayed resistance to nalidixic acid (minimum inhibitory concentration [MIC] > 32 μg/mL). All nalidixic acid-resistant isolates were also ciprofloxacin-sensitive. All isolates were ESBL-negative. Twenty-one percent of isolates were found to be resistant to chloramphenicol (MIC ≥ 32 μg/mL), and 16% were resistant to ampicillin (MIC ≥ 32 μg/mL). Conclusions The results indicate that multidrug-resistant (MDR) strains of Salmonella are increasing in number, and fewer antibiotics may be useful for

  1. In vitro effect of antibiotics on biofilm formation by Bacteroides fragilis group strains isolated from intestinal microbiota of dogs and their antimicrobial susceptibility.

    PubMed

    Silva, Janice Oliveira; Martins Reis, Ana Catarina; Quesada-Gómez, Carlos; Pinheiro, Adriana Queiroz; Freire, Rosemary Souza; Oriá, Reinaldo Barreto; de Carvalho, Cibele Barreto Mano

    2014-08-01

    The Bacteroides fragilis group strains colonize the intestinal tract of dogs as commensal bacteria. Nevertheless, they can be opportunistic pathogens responsible for significant morbidity and mortality rates in dogs, like in oral infections, abscesses and wound infections. The purpose of this study was to evaluate antimicrobial susceptibility in B. fragilis strains isolated from dogs intestinal microbiota and to evaluate the effect of subinhibitory concentrations of some antimicrobials on biofilm formation. A total of 30 B. fragilis group strains were tested for susceptibility to ten antimicrobial agents by broth microdilution method. Thirteen B. fragilis strains were tested for biofilm formation and the biofilm producer strains were chosen to evaluate the effect of subinhibitory concentrations of six antimicrobials on biofilm formation. The isolates were susceptible to amoxicillin-clavulanic acid, metronidazole, imipenem and chloramphenicol. Tetracycline and clindamycin were active against 50% and 33% of the strains, respectively. When biofilm-forming strains were grown in the presence of sub-MICs of imipenem and metronidazole, the inhibition of biofilm formation was observed. In contrast, enrofloxacin at ½ MIC caused a significant increase in biofilm formation in two of four strains examined. In conclusion, the B. fragilis group strains isolated were susceptible to most of the antimicrobials tested and the sub-MIC concentrations of imipenem, metronidazole and clindamycin were able to inhibit the biofilm formation. PMID:24799339

  2. [Proposals of the working group "Antibiotic resistance" for the configuration of microtitre plates to be used in routine antimicrobial susceptibility testing of bacterial pathogens from infections of large food-producing animals and mastitis cases].

    PubMed

    Luhofer, Gabriele; Böttner, Alexander; Hafez, H Mohamed; Kaske, Martin; Kehrenberg, Corinna; Kietzmann, Manfred; Klarmann, Dieter; Klein, Günter; Krabisch, Peter; Kühn, Tilman; Richter, Angelika; Sigge, Claudia; Traeder, Wolfgang; Waldmann, Karl-Heinz; Wallmann, Jürgen; Werckenthin, Christiane; Schwarz, Stefan

    2004-01-01

    Two layouts for microtitre plates, which should serve for in-vitro susceptibility testing in routine diagnostics, have been set up by the working group "Antibiotic resistance" of the German Society for Veterinary Medicine. One of these layouts was designed for the testing of bacteria from cases of mastitis and the other for bacteria from infections in large food-producing animals. The choice of the antimicrobial agents and their concentrations to be included in these layouts were based on (1) the bacteria frequently associated with the respective diseases/animals, (2) the antimicrobial agents licensed for therapeutic use in these diseases/animals, (3) the currently available breakpoints, and (4) cross-resistances between the antimicrobial agerts so far known to occur in the respective bacteria. PMID:15298050

  3. SUSCEPTIBILITY TO ANTIBIOTICS IN URINARY TRACT INFECTIONS IN A SECONDARY CARE SETTING FROM 2005-2006 AND 2010-2011, IN SÃO PAULO, BRAZIL: DATA FROM 11,943 URINE CULTURES

    PubMed Central

    Miranda, Érique José Peixoto De; Oliveira, Gerson Sobrinho Salvador De; Roque, Felício Lopes; Santos, Sílvia Regina Dos; Olmos, Rodrigo Diaz; Lotufo, Paulo Andrade

    2014-01-01

    Introduction: Urinary tract infection (UTI) has a high incidence and recurrence, therefore, treatment is empirical in the majority of cases. Objectives: The aim of this study was to analyze the urine cultures performed at a secondary hospital, during two periods, 2005-2006 and 2010-2011, and to estimate the microbial resistance. Patients and methods: We analyzed 11,943 aerobic urine cultures according to basic demographic data and susceptibility to antibiotics in accordance with the Clinical and Laboratory Standards Institute (CLSI) for Vitek 1 and 2. Results: Most of our cohort consisted of young adult females that were seen at the Emergency Department. E. coli was the most frequent (70.2%) among the 75 species isolated. Resistance of all isolates was ≥ 20% for trimethoprim/sulfamethoxazole (TMP/SMX), norfloxacin, nitrofurantoin, cefazolin and nalidixic acid. Although E. coli was more susceptible (resistance ≥ 20% for TMP/SMX and nalidixic acid) among all of the isolates, when classified by the number and percentage of antibiotic resistance. Global resistance to fluoroquinolones was approximately 12%. Risk factors for E. coli were female gender and an age less than 65 years. Men and patients older than 65 years of age, presented more resistant isolates. Extended spectrum beta-lactamases (ESBL) were identified in 173 out of 5,722 Gram-negative isolates (3.0%) between 2010 and 2011. Conclusion: E. coli was the most frequent microbe isolated in the urine cultures analyzed in this study. There was a significant evolution of bacterial resistance between the two periods studied. In particular, the rise of bacterial resistance to fluoroquinolones was concerning. PMID:25076433

  4. Real-time video imaging as a new and rapid tool for antibiotic susceptibility testing by the disc diffusion method: a paradigm for evaluating resistance to imipenem and identifying extended-spectrum β-lactamases.

    PubMed

    Le Page, Stéphanie; Raoult, Didier; Rolain, Jean-Marc

    2015-01-01

    The disc diffusion method has long been considered the standard technique for antibiotic susceptibility testing (AST) in clinical microbiology laboratories because of its simplicity, reproducibility and low cost compared with commercial automated microdilution systems that are usually more rapid but less sensitive for detecting important mechanisms of resistance. Here we measured reading zone diameters around antibiotics in a series of 25 well-characterised Gram-negative bacteria by the disc diffusion technique in real-time using an Advencis Bio-System instrument consisting of a real-time high-resolution video imager in a dedicated incubator. The susceptibility of wild-type Gram-negative bacteria to imipenem, determined by reading the diameter of inhibition, was detectable as early as 3.5h (mean time 3.7 ± 0.45 h), whereas carbapenemase-producing Gram-negative bacteria could be correctly categorised as early as 3h (mean time 4.2 ± 0.8 h) of incubation. Similarly, the characteristic champagne cork aspect of extended-spectrum β-lactamase (ESBL) could be detected by the system as early as 3.5 h. Moreover, we present here for the first time video movies of the appearance of the diameter of inhibition by disc diffusion in real-time. This preliminary study using a new and innovative technology provides for a renewed interest for microbiologists who wish to continue to use the disc diffusion method as a reference method for AST. New video imaging technology presents a proof of concept that could improve the real-time management of patients with AST within a very rapid turnaround time and can provide a large financial saving for hospitals. PMID:25455851

  5. Microbial Contaminants of Cord Blood Units Identified by 16S rRNA Sequencing and by API Test System, and Antibiotic Sensitivity Profiling.

    PubMed

    França, Luís; Simões, Catarina; Taborda, Marco; Diogo, Catarina; da Costa, Milton S

    2015-01-01

    Over a period of ten months a total of 5618 cord blood units (CBU) were screened for microbial contamination under routine conditions. The antibiotic resistance profile for all isolates was also examined using ATB strips. The detection rate for culture positive units was 7.5%, corresponding to 422 samples.16S rRNA sequence analysis and identification with API test system were used to identify the culturable aerobic, microaerophilic and anaerobic bacteria from CBUs. From these samples we recovered 485 isolates (84 operational taxonomic units, OTUs) assigned to the classes Bacteroidia, Actinobacteria, Clostridia, Bacilli, Betaproteobacteria and primarily to the Gammaproteobacteria. Sixty-nine OTUs, corresponding to 447 isolates, showed 16S rRNA sequence similarities above 99.0% with known cultured bacteria. However, 14 OTUs had 16S rRNA sequence similarities between 95 and 99% in support of genus level identification and one OTU with 16S rRNA sequence similarity of 90.3% supporting a family level identification only. The phenotypic identification formed 29 OTUs that could be identified to the species level and 9 OTUs that could be identified to the genus level by API test system. We failed to obtain identification for 14 OTUs, while 32 OTUs comprised organisms producing mixed identifications. Forty-two OTUs covered species not included in the API system databases. The API test system Rapid ID 32 Strep and Rapid ID 32 E showed the highest proportion of identifications to the species level, the lowest ratio of unidentified results and the highest agreement to the results of 16S rRNA assignments. Isolates affiliated to the Bacilli and Bacteroidia showed the highest antibiotic multi-resistance indices and microorganisms of the Clostridia displayed the most antibiotic sensitive phenotypes. PMID:26512991

  6. Microbial Contaminants of Cord Blood Units Identified by 16S rRNA Sequencing and by API Test System, and Antibiotic Sensitivity Profiling

    PubMed Central

    França, Luís; Simões, Catarina; Taborda, Marco; Diogo, Catarina; da Costa, Milton S.

    2015-01-01

    Over a period of ten months a total of 5618 cord blood units (CBU) were screened for microbial contamination under routine conditions. The antibiotic resistance profile for all isolates was also examined using ATB strips. The detection rate for culture positive units was 7.5%, corresponding to 422 samples.16S rRNA sequence analysis and identification with API test system were used to identify the culturable aerobic, microaerophilic and anaerobic bacteria from CBUs. From these samples we recovered 485 isolates (84 operational taxonomic units, OTUs) assigned to the classes Bacteroidia, Actinobacteria, Clostridia, Bacilli, Betaproteobacteria and primarily to the Gammaproteobacteria. Sixty-nine OTUs, corresponding to 447 isolates, showed 16S rRNA sequence similarities above 99.0% with known cultured bacteria. However, 14 OTUs had 16S rRNA sequence similarities between 95 and 99% in support of genus level identification and one OTU with 16S rRNA sequence similarity of 90.3% supporting a family level identification only. The phenotypic identification formed 29 OTUs that could be identified to the species level and 9 OTUs that could be identified to the genus level by API test system. We failed to obtain identification for 14 OTUs, while 32 OTUs comprised organisms producing mixed identifications. Forty-two OTUs covered species not included in the API system databases. The API test system Rapid ID 32 Strep and Rapid ID 32 E showed the highest proportion of identifications to the species level, the lowest ratio of unidentified results and the highest agreement to the results of 16S rRNA assignments. Isolates affiliated to the Bacilli and Bacteroidia showed the highest antibiotic multi-resistance indices and microorganisms of the Clostridia displayed the most antibiotic sensitive phenotypes. PMID:26512991

  7. An outbreak of scrub typhus in military personnel despite protocols for antibiotic prophylaxis: doxycycline resistance excluded by a quantitative PCR-based susceptibility assay.

    PubMed

    Harris, Patrick N A; Oltvolgyi, Csongor; Islam, Aminul; Hussain-Yusuf, Hazizul; Loewenthal, Mark R; Vincent, Gemma; Stenos, John; Graves, Stephen

    2016-06-01

    Scrub typhus is caused by the obligate intracellular bacterium Orientia tsutsugamushi and is endemic to many countries in the Asia-Pacific region, including tropical Australia. We describe a recent large outbreak amongst military personnel in north Queensland. A total of 45 clinical cases were identified (36% of all potentially exposed individuals). This occurred despite existing military protocols stipulating the provision of doxycycline prophylaxis. Doxycycline resistance in O. tsutsugamushi has been described in South-East Asia, but not Australia. In one case, O. tsutsugamushi was cultured from eschar tissue and blood. Using quantitative real-time PCR to determine susceptibility to doxycycline for the outbreak strain, a minimum inhibitory concentration (MIC) of ≤0.04 μg/mL was found, indicating susceptibility to this agent. It seems most probable that failure to adhere to adequate prophylaxis over the duration of the military exercise accounted for the large number of cases encountered rather than doxycycline resistance. PMID:27005452

  8. A study of Salmonella in pigs from birth to carcass: serotypes, genotypes, antibiotic resistance and virulence profiles.

    PubMed

    Bolton, Declan J; Ivory, Claire; McDowell, David

    2013-01-01

    A study was undertaken to investigate Salmonella in pigs at each step from birth to carcass. Environmental and/or pig samples were taken at birth, farrowing, 1st weaning, 2nd weaning, finishing, transport, lairage, bleeding and chilling of carcasses and tested for Salmonella. All isolates were characterised in terms of serotype, phage type (where relevant) and subtyping with pulsed field gel electrophosesis (PFGE). Isolates were tested for antibiotic resistance, resistance (intI1, bla(CIT), bla(Tem), bla(PSE-1), bla(OXA-1), floR, catA1, aadA1, aadA2, tetA, tetB, tetG, sul1and aphA1) and virulence (invA, rck, spvC and pefA) genes. PCR was also performed to test for the presence of the left junction, thdF-S001 and the right junction, S004-int2 or S004-yidY of Salmonella genomic island 1 (SGI1). Overall 4.3%, 27.5% and 5% of environmental, throat/rectal and carcass samples were Salmonella positive, respectively. S. Typhimurium DT193 was detected during production, while S. Typhimurium DT17 and U311 were present in lairage at the abattoir, where strain characterisation suggested cross contamination of the live animals occurred. The carcasses were also cross contaminated with S. Brandenburg during processing. PFGE grouped the isolates by serotype and/or phage type. The DT193 isolates displayed the ACSSuTTmMn/Gm resistance phenotype and carried the invA, spvC, rck, bla-tem, aadA2, tetA, strA virulence/antibiotic resistance markers; U311 showed an ASSuTMn resistance pattern and carried invA and tetB; DT17 was sensitive to all antibiotics tested but invA, spv and rck positive while S. Brandenburg displayed neither resistance nor virulence gene carriage. None of the isolates possessed class 1 integrons and all isolates were negative for the left and right junctions of SGI1. It was concluded that control activities should target improved biosecurity at farm level and better sanitation in lairage. This study also provides further evidence that multiple drug resistance may be

  9. Antibiotic Agents

    MedlinePlus

    ... Work Contact Us ABOUT THE ISSUE What is Antibiotic Resistance? General Background Science of Resistance Glossary References POLICY ... for Adaptation Genetics and Drug Resistance Reservoirs of Antibiotic Resistance Project (ROAR) INTERNATIONAL CHAPTERS APUA Chapter Network Africa ...

  10. Antibiotic Safety

    MedlinePlus

    ... specific to women Antibiotics can lead to vaginal yeast infections. This happens because antibiotics kill the normal bacteria in the vagina and this causes yeast to grow rapidly. Symptoms of a yeast infection ...

  11. Evaluation of Genome-Wide Expression Profiles of Blood and Sputum Neutrophils in Cystic Fibrosis Patients Before and After Antibiotic Therapy

    PubMed Central

    Conese, Massimo; Castellani, Stefano; Lepore, Silvia; Palumbo, Orazio; Manca, Antonio; Santostasi, Teresa; Polizzi, Angela Maria; Copetti, Massimiliano; Di Gioia, Sante; Casavola, Valeria; Guerra, Lorenzo; Diana, Anna; Montemurro, Pasqualina; Mariggiò, Maria Addolorata; Gallo, Crescenzio; Maffione, Angela Bruna; Carella, Massimo

    2014-01-01

    In seeking more specific biomarkers of the cystic fibrosis (CF) lung inflammatory disease that would be sensitive to antibiotic therapy, we sought to evaluate the gene expression profiles of neutrophils in CF patients before treatment in comparison with non-CF healthy individuals and after antibiotic treatment. Genes involved in neutrophil-mediated inflammation, i.e. chemotaxis, respiratory burst, apoptosis, and granule exocytosis, were the targets of this study. Microarray analysis was carried out in blood and airway neutrophils from CF patients and in control subjects. A fold change (log) threshold of 1.4 and a cut-off of p<0.05 were utilized to identify significant genes. Community networks and principal component analysis were used to distinguish the groups of controls, pre- and post-therapy patients. Control subjects and CF patients before therapy were readily separated, whereas a clear distinction between patients before and after antibiotic therapy was not possible. Blood neutrophils before therapy presented 269 genes down-regulated and 56 up-regulated as compared with control subjects. Comparison between the same patients before and after therapy showed instead 44 genes down-regulated and 72 up-regulated. Three genes appeared to be sensitive to therapy and returned to “healthy” condition: phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1), hydrogen voltage-gated channel 1 (HVCN1), and β-arrestin 1 (ARRB1). The up-regulation of these genes after therapy were confirmed by real time PCR. In airway neutrophils, 1029 genes were differentially expressed post- vs pre-therapy. Of these, 30 genes were up-regulated and 75 down-regulated following antibiotic treatment. However, biological plausibility determined that only down-regulated genes belonged to the gene classes studied for blood neutrophils. Finally, it was observed that commonly expressed genes showed a greater variability in airway neutrophils than that found in blood neutrophils, both before

  12. Linking microbial community structure and function to characterize antibiotic resistant bacteria and antibiotic resistant genes from cattle feces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is widespread interest in monitoring the development of antibiotic resistant bacteria and antibiotic resistance genes in agriculturally impacted environments, however little is known about the relationships between bacterial community structure, and antibiotic resistance gene profiles. Cattl...

  13. Identification and Antifungal Susceptibility Profile of Candida guilliermondii and Candida fermentati from a Multicenter Study in China.

    PubMed

    Cheng, Jing-Wei; Yu, Shu-Ying; Xiao, Meng; Wang, He; Kudinha, Timothy; Kong, Fanrong; Xu, Ying-Chun

    2016-08-01

    With molecular sequencing as a gold standard, the Vitek MS, Bruker Biotyper MS, and Vitek-2 Compact systems correctly identified 92.7%, 97.0%, and 15.2% of 164 Candida guillermondii isolates, respectively, and none of 8 C. fermentati isolates. All of the isolates showed high susceptibility to echinocandins, but some C. guilliermondii isolates showed low azole susceptibility. PMID:27252461

  14. Evaluation of polymyxin susceptibility profile among KPC-producing Klebsiella pneumoniae using Etest and MicroScan WalkAway automated system.

    PubMed

    Perez, Leandro Reus Rodrigues

    2015-11-01

    Determination of polymyxin susceptibility profile is important to monitor resistance rates and for implementing control measures for polymyxin-resistant carbapenem-resistant Enterobacteriaceae. Some laboratorial methods have been used to determine the polymyxin susceptibility profile. However, the performance of MicroScan WalkAway has been poorly reported for KPC-producing Klebsiella pneumoniae, so far. To evaluate two different methods, Etest and the MicroScan automated system, in determining minimal inhibitory concentration (MIC) of polymyxin among KPC-producing K. pneumoniae isolated from patients in two care units (ICUs) of a tertiary hospital in Porto Alegre, Southern Brazil. A total of 101 KPC-Kb isolates were obtained from rectal swabs and clinical specimens (urine, blood, and endotracheal aspirate). Colistin and polymyxin B MICs were determined using MicroScan WalkAway automated system and Etest, respectively. Discrepant results were resolved by broth microdilution (BMD). MicroScan showed 88.1% of sensitivity for predicting polymyxin B resistance in KPC-producing K. pneumoniae compared to the results obtained by Etest. All discrepant results were tested by BMD and these were concordant with results obtained by Etest. The MicroScan automated system does not seem to be very efficient for the screening of polymyxin-resistant isolates once an inappropriate sensitivity is achieved. The results presented here show the need for confirmation of the susceptibility profile by use of a dilution method (Etest or BMD). PMID:26361367

  15. A Rapid Molecular Test for Determining Yersinia pestis Susceptibility to Ciprofloxacin by the Quantification of Differentially Expressed Marker Genes

    PubMed Central

    Steinberger-Levy, Ida; Shifman, Ohad; Zvi, Anat; Ariel, Naomi; Beth-Din, Adi; Israeli, Ofir; Gur, David; Aftalion, Moshe; Maoz, Sharon; Ber, Raphael

    2016-01-01

    Standard antimicrobial susceptibility tests used to determine bacterial susceptibility to antibiotics are growth dependent and time consuming. The long incubation time required for standard tests may render susceptibility results irrelevant, particularly for patients infected with lethal bacteria that are slow growing on agar but progress rapidly in vivo, such as Yersinia pestis. Here, we present an alternative approach for the rapid determination of antimicrobial susceptibility, based on the quantification of the changes in the expression levels of specific marker genes following exposure to growth-inhibiting concentrations of the antibiotic, using Y. pestis and ciprofloxacin as a model. The marker genes were identified by transcriptomic DNA microarray analysis of the virulent Y. pestis Kimberley53 strain after exposure to specific concentrations of ciprofloxacin for various time periods. We identified several marker genes that were induced following exposure to growth-inhibitory concentrations of ciprofloxacin, and we confirmed the marker expression profiles at additional ciprofloxacin concentrations using quantitative RT-PCR. Eleven candidate marker transcripts were identified, of which four mRNA markers were selected for a rapid quantitative RT-PCR susceptibility test that correctly determined the Minimal Inhibitory Concentration (MIC) values and the categories of susceptibility of several Y. pestis strains and isolates harboring various ciprofloxacin MIC values. The novel molecular susceptibility test requires just 2 h of antibiotic exposure in a 7-h overall test time, in contrast to the 24 h of antibiotic exposure required for a standard microdilution test. PMID:27242774

  16. A Rapid Molecular Test for Determining Yersinia pestis Susceptibility to Ciprofloxacin by the Quantification of Differentially Expressed Marker Genes.

    PubMed

    Steinberger-Levy, Ida; Shifman, Ohad; Zvi, Anat; Ariel, Naomi; Beth-Din, Adi; Israeli, Ofir; Gur, David; Aftalion, Moshe; Maoz, Sharon; Ber, Raphael

    2016-01-01

    Standard antimicrobial susceptibility tests used to determine bacterial susceptibility to antibiotics are growth dependent and time consuming. The long incubation time required for standard tests may render susceptibility results irrelevant, particularly for patients infected with lethal bacteria that are slow growing on agar but progress rapidly in vivo, such as Yersinia pestis. Here, we present an alternative approach for the rapid determination of antimicrobial susceptibility, based on the quantification of the changes in the expression levels of specific marker genes following exposure to growth-inhibiting concentrations of the antibiotic, using Y. pestis and ciprofloxacin as a model. The marker genes were identified by transcriptomic DNA microarray analysis of the virulent Y. pestis Kimberley53 strain after exposure to specific concentrations of ciprofloxacin for various time periods. We identified several marker genes that were induced following exposure to growth-inhibitory concentrations of ciprofloxacin, and we confirmed the marker expression profiles at additional ciprofloxacin concentrations using quantitative RT-PCR. Eleven candidate marker transcripts were identified, of which four mRNA markers were selected for a rapid quantitative RT-PCR susceptibility test that correctly determined the Minimal Inhibitory Concentration (MIC) values and the categories of susceptibility of several Y. pestis strains and isolates harboring various ciprofloxacin MIC values. The novel molecular susceptibility test requires just 2 h of antibiotic exposure in a 7-h overall test time, in contrast to the 24 h of antibiotic exposure required for a standard microdilution test. PMID:27242774

  17. Virulence potential and antibiotic susceptibility pattern of motile aeromonads associated with freshwater ornamental fish culture systems: a possible threat to public health

    PubMed Central

    Sreedharan, Krishnan; Philip, Rosamma; Singh, Isaac Sarojani Bright

    2012-01-01

    Aeromonas spp. are ubiquitous aquatic organisms, associated with multitude of diseases in several species of animals, including fishes and humans. In the present study, water samples from two ornamental fish culture systems were analyzed for the presence of Aeromonas. Nutrient agar was used for Aeromonas isolation, and colonies (60 No) were identified through biochemical characterization. Seven clusters could be generated based on phenotypic characters, analyzed by the programme NTSYSpc, Version 2.02i, and identified as: Aeromonas caviae (33.3%), A. jandaei (38.3%) and A. veronii biovar sobria (28.3%). The strains isolated produced highly active hydrolytic enzymes, haemolytic activity and slime formation in varying proportions. The isolates were also tested for the enterotoxin genes (act, alt and ast), haemolytic toxins (hlyA and aerA), involved in type 3 secretion system (TTSS: ascV, aexT, aopP, aopO, ascF-ascG, and aopH), and glycerophospholipid-cholesterol acyltransferase (gcat). All isolates were found to be associated with at least one virulent gene. Moreover, they were resistant to frequently used antibiotics for human infections. The study demonstrates the pathogenic potential of Aeromonas, associated with ornamental fish culture systems suggesting the emerging threat to public health. PMID:24031887

  18. Virulence potential and antibiotic susceptibility pattern of motile aeromonads associated with freshwater ornamental fish culture systems: a possible threat to public health.

    PubMed

    Sreedharan, Krishnan; Philip, Rosamma; Singh, Isaac Sarojani Bright

    2012-04-01

    Aeromonas spp. are ubiquitous aquatic organisms, associated with multitude of diseases in several species of animals, including fishes and humans. In the present study, water samples from two ornamental fish culture systems were analyzed for the presence of Aeromonas. Nutrient agar was used for Aeromonas isolation, and colonies (60 No) were identified through biochemical characterization. Seven clusters could be generated based on phenotypic characters, analyzed by the programme NTSYSpc, Version 2.02i, and identified as: Aeromonas caviae (33.3%), A. jandaei (38.3%) and A. veronii biovar sobria (28.3%). The strains isolated produced highly active hydrolytic enzymes, haemolytic activity and slime formation in varying proportions. The isolates were also tested for the enterotoxin genes (act, alt and ast), haemolytic toxins (hlyA and aerA), involved in type 3 secretion system (TTSS: ascV, aexT, aopP, aopO, ascF-ascG, and aopH), and glycerophospholipid-cholesterol acyltransferase (gcat). All isolates were found to be associated with at least one virulent gene. Moreover, they were resistant to frequently used antibiotics for human infections. The study demonstrates the pathogenic potential of Aeromonas, associated with ornamental fish culture systems suggesting the emerging threat to public health. PMID:24031887

  19. Antibiotic susceptibility pattern in urinary isolates of gram negative bacilli with special reference to AmpC β-lactamase in a tertiary care hospital

    PubMed Central

    Patel, Mitesh H.; Trivedi, Grishma R.; Patel, Sachin M.; Vegad, Mahendra M.

    2010-01-01

    Introduction: Resistance to higher antimicrobial agent is commonly seen in gram negative bacilli. This issue is a challenging problem to the medical practitioners in addition to it is financial impact on the health care system. Objectives: To document the prevalence of multi drug resistant gram negative bacilli isolated from urine of patients attending the Urology Department of Tertiary care Hospital of western India in year 2008. Results: Out of total 328 isolates, 118 (35.98%) E.coli, 72 (21.95 %) Klebsiella, 64 (19.51%) Pseudomonas aeruginosa, 30 (9.15%) Acinetobacter, 18 (5.49%) Proteus vulgaris, 18 (5.49%) Proteus mirabilis, 6 (1.83%) Providencia rettgerii, 2 (0.61%) Citrobacter freundii. Out of these isolates, 228 (69.51%) were β-lactamase positive, while 100 (30.51%) were β-lactamase negative. Out of 228 β-lactamase positive, 104 (45.61%) were AmpC β-lactamase positive. Conclusions: Stringent protocol such as Antibiotic policy and Hospital infection control program are mandatory to curb these microbes in a tertiary care hospital. PMID:20842250

  20. Prevalence, serovars, phage types, and antibiotic susceptibilities of Salmonella strains isolated from animals in the United Arab Emirates from 1996 to 2009.

    PubMed

    Münch, Sebastian; Braun, Peggy; Wernery, Ulrich; Kinne, Jörg; Pees, Michael; Flieger, Antje; Tietze, Erhard; Rabsch, Wolfgang

    2012-10-01

    The aim of this study was to give some insights into the prevalence, serovars, phage types, and antibiotic resistances of Salmonella from animal origin in the United Arab Emirates. Data on diagnostic samples from animals (n = 20,871) examined for Salmonella between 1996 and 2009 were extracted from the databases of the Central Veterinary Research Laboratory in Dubai and from typed strains (n = 1052) from the Robert Koch Institute, Wernigerode Branch in Germany and analyzed for general and animal-specific trends. Salmonella was isolated from 1,928 (9 %) of the 20,871 samples examined. Among the 1,052 typed strains, most were from camels (n = 232), falcons (n = 166), bustards (n = 101), antelopes (n = 66), and horses (n = 63). The predominant serovars were Salmonella Typhimurium (25 %), Salmonella Kentucky (8 %), followed by Salmonella Frintrop (7 %), and Salmonella Hindmarsh (5 %). When analyzed by animal species, the most frequent serovars in camels were Salmonella Frintrop (28 %) and Salmonella Hindmarsh (21 %), in falcons Salmonella Typhimurium (32 %), in bustards Salmonella Kentucky (19 %), in antelopes Salmonella Typhimurium (9 %), and in horses Salmonella Typhimurium (17 %) and S. Kentucky (16 %). Resistance of all typed Salmonella strains (n = 1052) was most often seen to tetracycline (23 %), streptomycin (22 %), nalidixic acid (18 %), and ampicillin (15 %). These data show trends in the epidemiology of Salmonella in different animal species which can be used as a base for future prevention, control, and therapy strategies. PMID:22476789

  1. Antibiotic resistance of Vibrio parahaemolyticus and Vibrio vulnificus in various countries: A review.

    PubMed

    Elmahdi, Sara; DaSilva, Ligia V; Parveen, Salina

    2016-08-01

    Vibrio parahaemolyticus and Vibrio vulnificus are the leading causes of seafood associated infections and mortality in the United States. The main syndromes caused by these pathogens are gastroenteritis, wound infections, and septicemia. This article reviewed the antibiotic resistance profile of V. parahaemolyticus and V. vulnificus in the United States and other countries including Italy, Brazil, Philippines, Malaysia, Thailand, China, India, Iran, South Africa and Australia. The awareness of antimicrobial resistance of these two pathogens is not as well documented as other foodborne bacterial pathogens. Vibrio spp. are usually susceptible to most antimicrobials of veterinary and human significance. However, many studies reported that V. vulnificus and V. parahaemolyticus showed multiple-antibiotic resistance due to misuse of antibiotics to control infections in aquaculture production. In addition, both environmental and clinical isolates showed similar antibiotic resistance profiles. Most frequently observed antibiotic resistance profiles involved ampicillin, penicillin and tetracycline regardless of the countries. The presence of multiple-antibiotic resistant bacteria in seafood and aquatic environments is a major concern in fish and shellfish farming and human health. PMID:27052711

  2. Results of a pilot antibiotic resistance survey of Albanian poultry farms.

    PubMed

    Alcaine, S D; Molla, L; Nugen, S R; Kruse, H

    2016-03-01

    Global dissemination of antibiotic-resistant bacteria in food animals is a major public health concern. Whilst many countries have implemented prudent antibiotic use policies and surveillance systems both in clinical and veterinary settings, there are no such systems in place in Albania and little is known about the levels of antibiotic-resistant bacteria in food animals within the country. A total of 172 poultry samples were taken from six Albanian farms over a 3-month period and were tested for the presence of Enterobacteriaceae. In total, 91 bacterial isolates were obtained and were characterised by species (Escherichia coli, Salmonella spp. or other Enterobacteriaceae) and by susceptibility to 11 antibiotics. Resistance rates of E. coli and Salmonella isolates were, respectively: amoxicillin (86%, 64%); chloramphenicol (77%, 82%); ciprofloxacin (93%, 73%); cefotaxime (14%, 0%); gentamicin (12%, 0%); kanamycin (30%, 18%); nalidixic acid (91%, 73%); streptomycin (70%, 55%); sulphonamides (91%, 73%); tetracycline (95%, 73%); and trimethoprim (79%, 64%). Multidrug resistance to at least four antibiotics was observed in 95% of E. coli isolates and 82% of Salmonella. In conclusion, these data indicate that: (i) Salmonella and E. coli isolates from Albanian poultry farms exhibit high to extremely high levels of antibiotic resistance; (ii) Salmonella and E. coli isolates exhibit resistance to multiple antibiotics; and (iii) multidrug resistance profiles among Enterobacteriaceae are geographically widespread. Implementation of prudent antibiotic use policies in food animals and related surveillance will be necessary to reduce the emergence, spread and establishment of highly resistant strains across poultry farms in Albania. PMID:27436396

  3. Secondary metabolite profiles and antifungal drug susceptibility of Aspergillus fumigatus and closely related species, Aspergillus lentulus, Aspergillus udagawae, and Aspergillus viridinutans.

    PubMed

    Tamiya, Hiroyuki; Ochiai, Eri; Kikuchi, Kazuyo; Yahiro, Maki; Toyotome, Takahito; Watanabe, Akira; Yaguchi, Takashi; Kamei, Katsuhiko

    2015-05-01

    The incidence of Aspergillus infection has been increasing in the past few years. Also, new Aspergillus fumigatus-related species, namely Aspergillus lentulus, Aspergillus udagawae, and Aspergillus viridinutans, were shown to infect humans. These fungi exhibit marked morphological similarities to A. fumigatus, albeit with different clinical courses and antifungal drug susceptibilities. The present study used liquid chromatography/time-of-flight mass spectrometry to identify the secondary metabolites secreted as virulence factors by these Aspergillus species and compared their antifungal susceptibility. The metabolite profiles varied widely among A. fumigatus, A. lentulus, A. udagawae, and A. viridinutans, producing 27, 13, 8, and 11 substances, respectively. Among the mycotoxins, fumifungin, fumiquinazoline A/B and D, fumitremorgin B, gliotoxin, sphingofungins, pseurotins, and verruculogen were only found in A. fumigatus, whereas auranthine was only found in A. lentulus. The amount of gliotoxin, one of the most abundant mycotoxins in A. fumigatus, was negligible in these related species. In addition, they had decreased susceptibility to antifungal agents such as itraconazole and voriconazole, even though metabolites that were shared in the isolates showing higher minimum inhibitory concentrations than epidemiological cutoff values were not detected. These strikingly different secondary metabolite profiles may lead to the development of more discriminative identification protocols for such closely related Aspergillus species as well as improved treatment outcomes. PMID:25737146

  4. The drug susceptibility profile and inducible resistance to macrolides of Mycobacterium abscessus and Mycobacterium massiliense in Korea.

    PubMed

    Kim, Song Yee; Kim, Chang-Ki; Bae, Il Kwon; Jeong, Seok Hoon; Yim, Jae-Joon; Jung, Ji Ye; Park, Moo Suk; Kim, Young Sam; Kim, Se Kyu; Chang, Joon; Kang, Young Ae

    2015-02-01

    We conducted drug susceptibility testing (DST) against various antimicrobial agents, including new candidate drugs, and investigated the relationship between inducible resistance (IR) to macrolides and erm(41) gene in Mycobacterium abscessus complex. Sixty-two isolates of M. abscessus complex from 2 tertiary care hospitals in South Korea were tested against 10 antimicrobial agents. Thirty-five isolates were M. abscessus, and 27 were Mycobacterium massiliense. Amikacin, moxifloxacin, linezolid, clofazimine, and tigecycline were active against most isolates and cefoxitin and ciprofloxacin against moderate number of isolates. M. massiliense remained susceptible to macrolides; in contrast, M. abscessus became highly resistant on day 14 after incubation. DST pattern did not differ between clarithromycin and azithromycin. IR to clarithromycin was correlated with erm(41) genotype in M. abscessus. Variations in susceptibility to antimicrobial agents within species and the difference in DST patterns between M. abscessus and M. massiliense suggest that DST and identification of M. abscessus complex are significant before treatment. PMID:25467784

  5. Disinfectant and Antimicrobial Susceptibility Profiles of the Big Six Non-O157 Shiga Toxin-Producing Escherichia coli Strains from Food Animals and Humans.

    PubMed

    Beier, Ross C; Franz, Eelco; Bono, James L; Mandrell, Robert E; Fratamico, Pina M; Callaway, Todd R; Andrews, Kathleen; Poole, Toni L; Crippen, Tawni L; Sheffield, Cynthia L; Anderson, Robin C; Nisbet, David J

    2016-08-01

    The disinfectant and antimicrobial susceptibility profiles of 138 non-O157 Shiga toxin-producing Escherichia coli strains (STECs) from food animals and humans were determined. Antimicrobial resistance (AMR) was moderate (39.1% of strains) in response to 15 antimicrobial agents. Animal strains had a lower AMR prevalence (35.6%) than did human strains (43.9%) but a higher prevalence of the resistance profile GEN-KAN-TET. A decreasing prevalence of AMR was found among animal strains from serogroups O45 > O145 > O121 > O111 > O26 > O103 and among human strains from serogroups O145 > O103 > O26 > O111 > O121 > O45. One animal strain from serogroups O121 and O145 and one human strain from serogroup O26 had extensive drug resistance. A high prevalence of AMR in animal O45 and O121 strains and no resistance or a low prevalence of resistance in human strains from these serogroups suggests a source other than food animals for human exposure to these strains. Among the 24 disinfectants evaluated, all strains were susceptible to triclosan. Animal strains had a higher prevalence of resistance to chlorhexidine than did human strains. Both animal and human strains had a similar low prevalence of low-level benzalkonium chloride resistance, and animal and human strains had similar susceptibility profiles for most other disinfectants. Benzyldimethylammonium chlorides and C10AC were the primary active components in disinfectants DC&R and P-128, respectively, against non-O157 STECs. A disinfectant FS512 MIC ≥ 8 μg/ml was more prevalent among animal O121 strains (61.5%) than among human O121 strains (25%), which may also suggest a source of human exposure to STEC O121 other than food animals. Bacterial inhibition was not dependent solely on pH but was correlated with the presence of dissociated organic acid species and some undissociated acids. PMID:27497123

  6. Prevalence and Antibiotic Resistance Profiles of Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolated from Healthy Broilers in Shandong Province, China.

    PubMed

    Li, Song; Zhao, Miaomiao; Liu, Junhe; Zhou, Yufa; Miao, Zengmin

    2016-07-01

    Food-producing animals carrying extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) have posed a potential threat to human and animal health. However, information regarding ESBL-EC in the intensive broiler breeding areas of Shandong Province, People's Republic of China, is very limited. The goal of our study was to investigate the prevalence and drug resistance characteristics of ESBL-EC in healthy broilers from Shandong Province. A total of 142 ESBL-EC isolates were collected from four prefectures in Shandong Province from October 2014 to February 2015. ESBL-EC isolates were frequently detected (142 of 160 samples, 88.8%) in healthy broilers. Antibiotic susceptibility testing showed that all 142 ESBL-EC isolates were resistant to ampicillin, piperacillin, and cefazolin but were sensitive to imipenem and meropenem. All ESBL-EC isolates carried one or more of the bla genes, in which blaCTX-M, blaTEM-1, and blaSHV-5 genes were identified in 142, 106, and 5 isolates, respectively. The blaCTX-M gene includes blaCTX-M-15 (56), blaCTX-M-65 (42), blaCTX-M-55 (36), blaCTX-M-14 (21), blaCTX-M-79 (1), blaCTX-M-3 (1), blaCTX-M-123 (1), and blaCTX-M-132 (1). In addition, 17 ESBL-EC isolates cocarried the genes of the CTX-M-1 and CTX-M-9 groups. Our findings indicate that healthy broiler flocks in Shandong Province in China are an important reservoir for ESBL-EC, with blaCTX-M and blaTEM-1 being the prevalent resistance genes identified. PMID:27357036

  7. Volatile profiles of young leaves of Rutaceae spp. varying in susceptibility to the Asian citrus psyllid,(Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant volatiles were identified from six species in the family Rutaceae. These species had varying degrees of susceptibility to the Asian citrus psyllid as determined by direct counts of life stages. Using a push system involving charcoal-filtered humidified air, volatiles were adsorbed on SuperQ pa...

  8. Curing bacteria of antibiotic resistance: reverse antibiotics, a novel class of antibiotics in nature.

    PubMed

    Hiramatsu, Keiichi; Igarashi, Masayuki; Morimoto, Yuh; Baba, Tadashi; Umekita, Maya; Akamatsu, Yuzuru

    2012-06-01

    By screening cultures of soil bacteria, we re-discovered an old antibiotic (nybomycin) as an antibiotic with a novel feature. Nybomycin is active against quinolone-resistant Staphylococcus aureus strains with mutated gyrA genes but not against those with intact gyrA genes against which quinolone antibiotics are effective. Nybomycin-resistant mutant strains were generated from a quinolone-resistant, nybomycin-susceptible, vancomycin-intermediate S. aureus (VISA) strain Mu 50. The mutants, occurring at an extremely low rate (<1 × 10(-11)/generation), were found to have their gyrA genes back-mutated and to have lost quinolone resistance. Here we describe nybomycin as the first member of a novel class of antibiotics designated 'reverse antibiotics'. PMID:22534508

  9. Antibiotics in Animal Products

    NASA Astrophysics Data System (ADS)

    Falcão, Amílcar C.

    The administration of antibiotics to animals to prevent or treat diseases led us to be concerned about the impact of these antibiotics on human health. In fact, animal products could be a potential vehicle to transfer drugs to humans. Using appropri ated mathematical and statistical models, one can predict the kinetic profile of drugs and their metabolites and, consequently, develop preventive procedures regarding drug transmission (i.e., determination of appropriate withdrawal periods). Nevertheless, in the present chapter the mathematical and statistical concepts for data interpretation are strictly given to allow understanding of some basic pharma-cokinetic principles and to illustrate the determination of withdrawal periods

  10. In vitro cytokine profile revealed differences from dorsal and ventral skin susceptibility to pathogen-probiotic interaction in gilthead seabream.

    PubMed

    Cordero, Héctor; Mauro, Manuela; Cuesta, Alberto; Cammarata, Matteo; Esteban, María Ángeles

    2016-09-01

    Skin is the first barrier of defense on fish, which is crucial to protection against different stressors, including pathogens. Skin samples obtained from dorsal and ventral part of Sparus aurata specimens were incubated with Photobacterium damselae subsp. piscicida (a pathogen for this fish species), with Shewanella putrefaciens Pdp11 (a probiotic bacteria isolated from healthy gilthead seabream skin) or with both bacteria. The gene expression profile of nine cytokines (il1b, tnfa, il6, il7, il8, il15, il18, il10 and tgfb) was studied by qPCR in all the skin samples. The present findings revealed different patterns of cytokine profile in dorsal and ventral skin of gilthead seabream, which could be related to the influence and susceptibility to a possible infection. PMID:27422755

  11. Plasmid Mediated Antibiotic Resistance in Isolated Bacteria From Burned Patients

    PubMed Central

    Beige, Fahimeh; Baseri Salehi, Majid; Bahador, Nima; Mobasherzadeh, Sina

    2014-01-01

    Background: Nowadays, the treatment of burned patients is difficult because of the high frequency of infection with antibiotic resistance bacteria. Objectives: This study was conducted to evaluate the level of antibiotic resistance in Gram-negative bacteria and its relation with the existence of plasmid. Materials and Methods: The samples were collected from two hundred twenty hospitalized burned patients in Isfahan burn hospital during a three-month period (March 2012 to June 2012). The samples were isolated and the Gram-negative bacteria were identified using phenotypic method and API 20E System. Antibiotic susceptibility and plasmid profile were determined by standard Agar disc diffusion and plasmid spin column extraction methods. Results: Totally 117 Gram-negative bacteria were isolated, the most common were Pseudomonas aerugionsa (37.6%), P. fluorescens (25.6%), Acinetobacter baumanii (20/5%) and Klebsiella pneumoniae (7.6%), respectively. The isolates showed high frequency of antibiotic resistance against ceftazidime and co-amoxiclave (100%) and low frequency of antibiotic resistance against amikacin with (70%).The results indicated that 60% of the isolates harboured plasmid. On the other hand, the patients infected with A. baumanii and P. aeruginosa were cured (with 60% frequency) whereas, those infected with P. fluorescens were not cured. Hence, probably antibiotic resistance markers of A. baumanii and P. aeruginosa are plasmid mediated; however, P. fluorescens is chromosomally mediated. Conclusions: Based on our findings, P. aerugionsa is a major causative agent of wound infections and amikacin could be considered as a more effective antibiotic for treatment of the burned patients. PMID:25789121

  12. Transcriptional Profiles of Host-Pathogen Responses to Necrotic Enteritis and Differential Regulation of Immune Genes in Two Inbreed Chicken Lines Showing Disparate Disease Susceptibility

    PubMed Central

    Kim, Duk Kyung; Lillehoj, Hyun S.; Jang, Seung I.; Lee, Sung Hyen; Hong, Yeong Ho; Cheng, Hans H.

    2014-01-01

    Necrotic enteritis (NE) is an important intestinal infectious disease of commercial poultry flocks caused by Clostridium perfringens. Using an experimental model of NE involving co-infection with C. perfringens and Eimeria maxima, transcriptome profiling and functional genomics approaches were applied to identify the genetic mechanisms that might regulate the host response to this disease. Microarray hybridization identified 1,049 transcripts whose levels were altered (601 increased, 448 decreased) in intestinal lymphocytes from C. perfringens/E. maxima co-infected Ross chickens compared with uninfected controls. Five biological functions, all related to host immunity and inflammation, and 11 pathways were identified from this dataset. To further elucidate the role of host genetics in NE susceptibility, two inbred chicken lines, ADOL line 6 and line 7 which share an identical B2 major histocompatibility complex haplotype but differ in their susceptibility to virus infection, were compared for clinical symptoms and the expression levels of a panel of immune-related genes during experimental NE. Line 6 chickens were more susceptible to development of experimental NE compared with line 7, as revealed by decreased body weight gain and increased E. maxima oocyst shedding. Of 21 immune-related genes examined, 15 were increased in C. perfringens/E. maxima co-infected line 6 vs. line 7 chickens. These results suggest that immune pathways are activated in response to experimental NE infection and that genetic determinants outside of the chicken B complex influence resistance to this disease. PMID:25504150

  13. Antimicrobial susceptibility profile of Pseudomonas spp. isolated from a swine slaughterhouse in Dourados, Mato Grosso do Sul State, Brazil.

    PubMed

    de Oliveira, Kelly M P; dos S Júlio, Péricles D; Grisolia, Alexéia B

    2013-01-01

    The present work sought to detect the presence of Pseudomonas spp. at different stages of an effluent treatment plant using the Australian system of stabilization ponds, and to determine the susceptibility of those isolates to different antimicrobials. Thirty-four isolates of Pseudomonas spp. derived from effluent treatment station water samples were collected near the transfer ducts between the ponds in November/2008 and december/2009. Among the Pseudomonas spp. isolates, 47.05 % showed susceptibility to all antimicrobials tested, 20.58 % were resistant to cefepime, and 24 % showed intermediate resistance to streptomycin. No Pseudomonas spp. isolates were found in the final pond, or in post-treatment effluents. The Pseudomonas spp. isolates did not exhibit multiresistance to the antimicrobials tested. PMID:23560791

  14. Mining metagenomic datasets for antibiotic resistance genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibiotics are medicines that are used to kill, slow down, or prevent the growth of susceptible bacteria. They became widely used in the mid 20th century for controlling disease in humans, animals, and plants, and for a variety of industrial purposes. Antibiotic resistance is a broad term. There ...

  15. Predictive Studies Suggest that the Risk for the Selection of Antibiotic Resistance by Biocides Is Likely Low in Stenotrophomonas maltophilia

    PubMed Central

    Sánchez, María Blanca; Decorosi, Francesca; Viti, Carlo; Oggioni, Marco Rinaldo; Martínez, José Luis; Hernández, Alvaro

    2015-01-01

    Biocides are used without restriction for several purposes. As a consequence, large amounts of biocides are released without any control in the environment, a situation that can challenge the microbial population dynamics, including selection of antibiotic resistant bacteria. Previous work has shown that triclosan selects Stenotrophomonas maltophilia antibiotic resistant mutants overexpressing the efflux pump SmeDEF and induces expression of this pump triggering transient low-level resistance. In the present work we analyze if two other common biocides, benzalkonium chloride and hexachlorophene, trigger antibiotic resistance in S. maltophilia. Bioinformatic and biochemical methods showed that benzalkonium chloride and hexachlorophene bind the repressor of smeDEF, SmeT. Only benzalkonium chloride triggers expression of smeD and its effect in transient antibiotic resistance is minor. None of the hexachlorophene-selected mutants was antibiotic resistant. Two benzalkonium chloride resistant mutants presented reduced susceptibility to antibiotics and were impaired in growth. Metabolic profiling showed they were more proficient than their parental strain in the use of some dipeptides. We can then conclude that although bioinformatic predictions and biochemical studies suggest that both hexachlorophene and benzalkonium chloride should induce smeDEF expression leading to transient S. maltophilia resistance to antibiotics, phenotypic assays showed this not to be true. The facts that hexachlorophene resistant mutants are not antibiotic resistant and that the benzalkonium chloride resistant mutants presenting altered susceptibility to antibiotics were impaired in growth suggests that the risk for the selection (and fixation) of S. maltophilia antibiotic resistant mutants by these biocides is likely low, at least in the absence of constant selection pressure. PMID:26201074

  16. Predictive Studies Suggest that the Risk for the Selection of Antibiotic Resistance by Biocides Is Likely Low in Stenotrophomonas maltophilia.

    PubMed

    Sánchez, María Blanca; Decorosi, Francesca; Viti, Carlo; Oggioni, Marco Rinaldo; Martínez, José Luis; Hernández, Alvaro

    2015-01-01

    Biocides are used without restriction for several purposes. As a consequence, large amounts of biocides are released without any control in the environment, a situation that can challenge the microbial population dynamics, including selection of antibiotic resistant bacteria. Previous work has shown that triclosan selects Stenotrophomonas maltophilia antibiotic resistant mutants overexpressing the efflux pump SmeDEF and induces expression of this pump triggering transient low-level resistance. In the present work we analyze if two other common biocides, benzalkonium chloride and hexachlorophene, trigger antibiotic resistance in S. maltophilia. Bioinformatic and biochemical methods showed that benzalkonium chloride and hexachlorophene bind the repressor of smeDEF, SmeT. Only benzalkonium chloride triggers expression of smeD and its effect in transient antibiotic resistance is minor. None of the hexachlorophene-selected mutants was antibiotic resistant. Two benzalkonium chloride resistant mutants presented reduced susceptibility to antibiotics and were impaired in growth. Metabolic profiling showed they were more proficient than their parental strain in the use of some dipeptides. We can then conclude that although bioinformatic predictions and biochemical studies suggest that both hexachlorophene and benzalkonium chloride should induce smeDEF expression leading to transient S. maltophilia resistance to antibiotics, phenotypic assays showed this not to be true. The facts that hexachlorophene resistant mutants are not antibiotic resistant and that the benzalkonium chloride resistant mutants presenting altered susceptibility to antibiotics were impaired in growth suggests that the risk for the selection (and fixation) of S. maltophilia antibiotic resistant mutants by these biocides is likely low, at least in the absence of constant selection pressure. PMID:26201074

  17. Prevalence, bacterial causes, and antimicrobial susceptibility profile of mastitis isolates from cows in large-scale dairy farms of Northern Ethiopia.

    PubMed

    Haftu, Rgbe; Taddele, Habtamu; Gugsa, Getachew; Kalayou, Shewit

    2012-10-01

    The study was undertaken to determine the prevalence of bovine mastitis, isolate mastitis causing bacteria, assess the association of some risk factors, and determine the antibiotic resistance pattern of bacterial isolates in cows in large-scale dairy farms of Northern Ethiopia. A total of 305 lactating and nonlactating cows were included in the present study. The overall prevalence of clinical and subclinical mastitis was 3.6 and 33.8 %, respectively. The quarter level prevalence was 15.4 %; from which, 11.9 and 1.1 % were subclinical form and blind teat, respectively, while the remaining 2.4 % were of clinical form. Staphylococcus aureus accounted for 36 % of the isolates followed by Escherichia coli (27.3 %). Risk factors including age (p < 0.001), parity (p < 0.001), and lactation stage (p = 0.02) showed significant association with the occurrence of mastitis. Higher prevalence was observed in both groups of older cows (i.e., 6-9 years (odds ratio (OR) = 4.65, 95 % confidence interval (CI) = 2.74-7.89) and >9 years (OR = 3.63, 95 % CI = 1.42-9.25)), cows with four to seven calves (OR = 3.39, 95 % CI = 2.06-5.60), and cows in late lactation stage (OR = 3.79, 95 % CI = 1.64-8.75). In multivariable logistic regression analysis, age (p = 0.005) and lactation stage (p = 0.027) showed statistically significant association with the occurrence of mastitis. The antimicrobial susceptibility pattern showed high susceptibility of S. aureus to nalidixic acid (82.4 %) followed by chloramphenicol (58.8 %); however, these species were resistant to the rest of the antimicrobials tested. Highest resistance was observed against clindamycin and ampicillin. Coliform bacteria (E. coli and Klebsiella pneumoniae) showed resistance to most of the antimicrobials used. Detailed investigation is needed to identify the interplay of managemental and environmental risk factors to design appropriate control measures. PMID:22476790

  18. Differences in the Gene Expression Profiles of Haemocytes from Schistosome-Susceptible and -Resistant Biomphalaria glabrata Exposed to Schistosoma mansoni Excretory-Secretory Products

    PubMed Central

    Davies, Angela J.; Kirk, Ruth S.; Emery, Aidan M.; Rollinson, David; Jones, Catherine S.; Noble, Leslie R.; Walker, Anthony J.

    2014-01-01

    During its life cycle, the helminth parasite Schistosoma mansoni uses the freshwater snail Biomphalaria glabrata as an intermediate host to reproduce asexually generating cercariae for infection of the human definitive host. Following invasion of the snail, the parasite develops from a miracidium to a mother sporocyst and releases excretory-secretory products (ESPs) that likely influence the outcome of host infection. To better understand molecular interactions between these ESPs and the host snail defence system, we determined gene expression profiles of haemocytes from S. mansoni-resistant or -susceptible strains of B. glabrata exposed in vitro to S. mansoni ESPs (20 μg/ml) for 1 h, using a 5K B. glabrata cDNA microarray. Ninety-eight genes were found differentially expressed between haemocytes from the two snail strains, 57 resistant specific and 41 susceptible specific, 60 of which had no known homologue in GenBank. Known differentially expressed resistant-snail genes included the nuclear factor kappa B subunit Relish, elongation factor 1α, 40S ribosomal protein S9, and matrilin; known susceptible-snail specific genes included cathepsins D and L, and theromacin. Comparative analysis with other gene expression studies revealed 38 of the 98 identified genes to be uniquely differentially expressed in haemocytes in the presence of ESPs, thus identifying for the first time schistosome ESPs as important molecules that influence global snail host-defence cell gene expression profiles. Such immunomodulation may benefit the schistosome, enabling its survival and successful development in the snail host. PMID:24663063

  19. [Antibiotic pharmacoeconomics].

    PubMed

    Jahnz-Rózyk, Karina

    2008-11-01

    Today more than ever, doctors in the ambulatory care and hospitals must effectively manage the use of antibiotics to control costs and preserve their usefulness. To achieve this goal, antibiotic management must evolve from simplistic antibiotic cost containment to more complex, appropriate use program that are founded on clinical outcomes-based pharmacoeconomic analyses. The successful application of pharmacoeconomic principles to antimicrobial therapy requires maximizing therapeutic effectiveness while minimizing costs, with the primary on pharmacokinetic considerations. This article reviews the various pharmacoeconomic factors that affect antibiotic costs in relation to patients and institutions. Cost-effectiveness studies of macrolides in pulmonary infections are presented in this study to illustrate the utility of these analyses. PMID:19177784

  20. Antibiotics Quiz

    MedlinePlus

    ... Viruses b) Bacteria c) Viruses and Bacteria 2. Bacteria are germs that cause colds and flu. a) ... The Flu c) Cold d) Strep Throat 4. Bacteria that cause infections can become resistant to antibiotics. ...

  1. Resistance-Resistant Antibiotics

    PubMed Central

    Oldfield, Eric; Feng, Xinxin

    2014-01-01

    New antibiotics are needed because as drug resistance is increasing, the introduction of new antibiotics is decreasing. Here, we discuss six possible approaches to develop ‘resistance-resistant’ antibiotics. First, multi-target inhibitors in which a single compound inhibits more than one target may be easier to develop than conventional combination therapies with two new drugs. Second, inhibiting multiple targets in the same metabolic pathway is expected to be an effective strategy due to synergy. Third, discovering multiple-target inhibitors should be possible by using sequential virtual screening. Fourth, re-purposing existing drugs can lead to combinations of multi-target therapeutics. Fifth, targets need not be proteins. Sixth, inhibiting virulence factor formation and boosting innate immunity may also lead to decreased susceptibility to resistance. Although it is not possible to eliminate resistance, the approaches reviewed here offer several possibilities for reducing the effects of mutations and in some cases suggest that sensitivity to existing antibiotics may be restored, in otherwise drug resistant organisms. PMID:25458541

  2. Transcriptome Profiling of Huanglongbing (HLB) Tolerant and Susceptible Citrus Plants Reveals the Role of Basal Resistance in HLB Tolerance

    PubMed Central

    Wang, Yunsheng; Zhou, Lijuan; Yu, Xiaoyue; Stover, Ed; Luo, Feng; Duan, Yongping

    2016-01-01

    Huanglongbing (HLB) is currently the most destructive disease of citrus worldwide. Although there is no immune cultivar, field tolerance to HLB within citrus and citrus relatives has been observed at the USDA Picos farm at Ft. Pierce, Florida, where plants have been exposed to a very high level of HLB pressure since 2006. In this study, we used RNA-Seq to evaluate expression differences between two closely related cultivars after HLB infection: HLB-tolerant “Jackson” grapefruit-like-hybrid trees and HLB susceptible “Marsh” grapefruit trees. A total of 686 genes were differentially expressed (DE) between the two cultivars. Among them, 247 genes were up-expressed and 439 were down-expressed in tolerant citrus trees. We also identified a total of 619 genes with significant differential expression of alternative splicing isoforms between HLB tolerant and HLB susceptible citrus trees. We analyzed the functional categories of DE genes using two methods, and revealed that multiple pathways have been suppressed or activated in the HLB tolerant citrus trees, which lead to the activation of the basal resistance or immunity of citrus plants. We have experimentally verified the expressions of 14 up-expressed genes and 19 down-expressed genes on HLB-tolerant “Jackson” trees and HLB-susceptible “Marsh” trees using real time PCR. The results showed that the expression of most genes were in agreement with the RNA-Seq results. This study provided new insights into HLB-tolerance and useful guidance for breeding HLB-tolerant citrus in the future. PMID:27446161

  3. Pulmonary vascular pressure profiles in broilers selected for susceptibility to pulmonary hypertension syndrome: age and sex comparisons.

    PubMed

    Wideman, R F; Eanes, M L; Hamal, K R; Anthony, N B

    2010-09-01

    Broilers that are susceptible to pulmonary hypertension syndrome (PHS, ascites) have an elevated pulmonary arterial pressure (PAP) when compared with PHS-resistant broilers. Two distinctly different syndromes, pulmonary arterial hypertension and pulmonary venous hypertension (PVH), both are associated with increases in PAP. Pulmonary arterial hypertension occurs when the right ventricle must elevate the PAP to overcome increased resistance to flow through restrictive pulmonary arterioles upstream from the pulmonary capillaries. In contrast, PVH is commonly caused by increased downstream (postcapillary) resistance. The sites of resistance to pulmonary blood flow are deduced by making contemporaneous measurements of the PAP and the wedge pressure (WP) and calculating the transpulmonary pressure gradient (TPG) (TPG = PAP - WP). We obtained PAP and WP values from 8-, 12-, 16-, 20-, and 24-wk-old anesthetized male and female broilers from a PHS-susceptible line. Pressures were recorded as a catheter was advanced through a wing vein to the pulmonary artery and onward until the WP was obtained. In addition to sex and age comparisons of vascular pressure gradients, the data also were pooled to obtain 3 cohorts for broilers having the lowest PAP values (n = 52; range: 12 to 22.9 mmHg), intermediate PAP values (n = 63; range: 23 to 32.9 mmHg), and highest PAP values (n = 62; range: 33 to 62 mmHg) independent of age or sex. Within each of the age, sex, and PAP cohort comparisons, broilers with elevated PAP consistently exhibited the hemodynamic characteristics of pulmonary arterial hypertension (elevated PAP and TPG combined with a normal WP) and not PVH (elevated PAP and WP combined with a normal or reduced TPG). Susceptibility to PHS can be attributed primarily to pulmonary arterial hypertension associated with increased precapillary (arteriole) resistance. PMID:20709965

  4. Pulmonary Vascular Pressure Profiles in Broilers Selected for Susceptibility to Pulmonary Hypertension Syndrome: Age and Gender Comparisons

    PubMed Central

    Wideman, R. F.; Eanes, M. L.; Hamal, K. R.; Anthony, N. B.

    2011-01-01

    Broilers that are susceptible to pulmonary hypertension syndrome (PHS, ascites) have an elevated pulmonary arterial pressure (PAP) when compared with PHS-resistant broilers. Two distinctly different syndromes, pulmonary arterial hypertension (PAH) and pulmonary venous hypertension (PVH), both are associated with increases in PAP. Pulmonary arterial hypertension occurs when the right ventricle must elevate the PAP to overcome increased resistance to flow through restrictive pulmonary arterioles upstream from the pulmonary capillaries. In contrast, PVH is commonly caused by increased downstream (post-capillary) resistance. The sites of resistance to pulmonary blood flow are deduced by making contemporaneous measurements of the PAP and the wedge pressure (WP), and calculating the trans-pulmonary pressure gradient (TPG = PAP-WP). We obtained PAP and WP values from 8, 12, 16, 20 and 24 wk old anesthetized male and female broilers from a PHS-susceptible line. Pressures were recorded as a catheter was advanced through a wing vein to the pulmonary artery and onward until the WP was obtained. In addition to gender and age comparisons of vascular pressure gradients, the data also were pooled to obtain three cohorts for broilers having the lowest PAP values (n = 52; range: 12 to 22.9 mmHg), intermediate PAP values (n = 63; range: 23 to 32.9 mmHg), and highest PAP values (n = 62; range: 33 to 62 mmHg) independent of age or gender. Within each of the age, gender and PAP cohort comparisons, broilers with elevated PAP consistently exhibited the hemodynamic characteristics of PAH (elevated PAP and TPG combined with a normal WP) and not PVH (elevated PAP and WP combined with a normal or reduced TPG). Susceptibility to PHS can be attributed primarily to pulmonary arterial hypertension associated with increased pre-capillary (arteriole) resistance. PMID:20709965

  5. Prevalence of Veterinary Antibiotics and Antibiotic-Resistant Escherichia coli in the Surface Water of a Livestock Production Region in Northern China

    PubMed Central

    Zhang, Xuelian; Li, Yanxia; Liu, Bei; Wang, Jing; Feng, Chenghong; Gao, Min; Wang, Lina

    2014-01-01

    This study investigated the occurrence of 12 veterinary antibiotics (VAs) and the susceptibility of Escherichia coli (E. coli) in a rural water system that was affected by livestock production in northern China. Each of the surveyed sites was determined with at least eight antibiotics with maximum concentration of up to 450 ng L−1. The use of VAs in livestock farming probably was a primary source of antibiotics in the rivers. Increasing total antibiotics were measured from up- to mid- and downstream in the two tributaries. Eighty-eight percent of the 218 E. coli isolates that were derived from the study area exhibited, in total, 48 resistance profiles against the eight examined drugs. Significant correlations were found among the resistance rates of sulfamethoxazole-trimethoprim, chloromycetin and ampicillin as well as between tetracycline and chlortetracycline, suggesting a possible cross-selection for resistance among these drugs. The E. coli resistance frequency also increased from up- to midstream in the three rivers. E. coli isolates from different water systems showed varying drug numbers of resistance. No clear relationship was observed in the antibiotic resistance frequency with corresponding antibiotic concentration, indicating that the antibiotic resistance for E. coli in the aquatic environment might be affected by factors besides antibiotics. High numbers of resistant E. coli were also isolated from the conserved reservoir. These results suggest that rural surface water may become a large pool of VAs and resistant bacteria. This study contributes to current information on VAs and resistant bacteria contamination in aquatic environments particularly in areas under intensive agriculture. Moreover, this study indicates an urgent need to monitor the use of VAs in animal production, and to control the release of animal-originated antibiotics into the environment. PMID:25372873

  6. Hybrid wound dressings with controlled release of antibiotics: Structure-release profile effects and in vivo study in a guinea pig burn model.

    PubMed

    Zilberman, Meital; Egozi, Dana; Shemesh, Maoz; Keren, Aviad; Mazor, Eytan; Baranes-Zeevi, Maya; Goldstein, Nyra; Berdicevsky, Israela; Gilhar, Amos; Ullmann, Yehuda

    2015-08-01

    Over the last decades, wound dressings have evolved from a crude traditional gauze dressing to tissue-engineered scaffolds. Many types of wound dressing formats are commercially available or have been investigated. We developed and studied hybrid bilayer wound dressings which combine a drug-loaded porous poly(dl-lactic-co-glycolic acid) top layer with a spongy collagen sublayer. Such a structure is very promising because it combines the advantageous properties of both layers. The antibiotic drug gentamicin was incorporated into the top layer for preventing and/or defeating infections. In this study, we examined the effect of the top layer's structure on the gentamicin release profile and on the resulting in vivo wound healing. The latter was tested on a guinea pig burn model, compared to the neutral non-adherent dressing material Melolin® (Smith & Nephew) and Aquacel® Ag (ConvaTec). The release kinetics of gentamicin from the various studied formulations exhibited burst release values between 8% and 38%, followed by a drug elution rate that decreased with time and lasted for at least 7 weeks. The hybrid dressing, with relatively slow gentamicin release, enabled the highest degree of wound healing (28%), which is at least double that obtained by the other dressing formats (8-12%). It resulted in the lowest degree of wound contraction and a relatively low amount of inflammatory cells compared to the controls. This dressing was found to be superior to hybrid wound dressings with fast gentamicin release and to the neat hybrid dressing without drug release. Since this dressing exhibited promising results and does not require frequent bandage changes, it offers a potentially valuable concept for treating large infected burns. PMID:25922303

  7. Clinico-microbiological study and antibiotic resistance profile of mecA and ESBL gene prevalence in patients with diabetic foot infections

    PubMed Central

    CHAUDHRY, WAQAS NASIR; BADAR, RABIA; JAMAL, MUHSIN; JEONG, JASON; ZAFAR, JAMAL; ANDLEEB, SAADIA

    2016-01-01

    Diabetic foot infections (DFIs) constitute a major complication of diabetes mellitus. DFIs contribute to the development of gangrene and non-traumatic lower extremity amputations with a lifetime risk of up to 25%. The aim of the present study was to identify the presence of neuropathy and determine the ulcer grade, microbial profile and phenotypic and genotypic prevalence of the methicillin-resistance gene mecA and extended spectrum β-lactamase (ESBL)-encoding genes in bacterial isolates of DFI in patients registered at the Pakistan Institute of Medical Sciences (Islamabad, Pakistan). The results indicated that 46/50 patients (92%), exhibited sensory neuropathy. The most common isolate was Staphylococcus aureus (25%), followed by Pseudomonas aeruginosa (P. aeruginosa; 18.18%), Escherichia coli (16.16%), Streptococcus species (spp.) (15.15%), Proteus spp. (15.15%), Enterococcus spp. (9%) and Klebsiella pneumoniae (K. pneumoniae; 3%). The prevalence of the mecA gene was found to be 88% phenotypically and 84% genotypically. K. pneumoniae was shown to have the highest percentage of ESBL producers with a prevalence of 66.7% by double disk synergy test, and 100% by the cefotaxime + clavulanic acid/ceftazidime + clavulanic acid combination disk test. P. aeruginosa and K. pneumoniae had the highest (100%) proportion of metallo β-lactamase producers as identified by the EDTA combination disk test. The overall prevalence of β-lactamase (bla)-CTX-M, bla-CTX-M-15, bla-TEM, bla-OXA and bla-SHV genes was found to be 76.9, 76.9, 75.0, 57.7 and 84.6%, respectively, in gram-negative DFI isolates. The prevalence of mecA and ESBL-related genes was found to be alarmingly high in DFIs, since these genes are a major cause of antibiotic treatment failure. PMID:26998033

  8. The host effects of Gambusia affinis with an antibiotic-disrupted microbiome.

    PubMed

    Carlson, Jeanette M; Hyde, Embriette R; Petrosino, Joseph F; Manage, Ananda B W; Primm, Todd P

    2015-12-01

    While serving as critical tools against bacterial infections, antimicrobial therapies can also result in serious side effects, such as antibiotic-associated entercolitis. Recent studies utilizing next generation sequencing to generate community 16S gene profiles have shown that antibiotics can strongly alter community composition and deplete diversity. However, how these community changes in the microbiota are related to the host side effects is still unclear. We have used the freshwater Western mosquitofish (Gambusia affinis) as a tractable vertebrate model system to study host effects following exposure to a broad spectrum antibiotic, rifampicin. After 3days of exposure, the bacterial communities of the mucosal skin and gut microbiomes lost diversity and shifted composition. Compared to unexposed controls, treated fish were more susceptible to a specific pathogen, Edwardsiella ictaluri, yet displayed no survival differences when subjected to a polymicrobial water challenge of soil or feces. Treated fish were more susceptible to osmotic stress from NaCl, but not to the toxin nitrate. Treated fish failed to gain weight as well as controls over one month when fed a matched diet. Because of small sample sizes, pathogen susceptibility and weight gain differences were not statistically significant. This study provides supporting evidence in an experimental laboratory system that an antibiotic can have significant and persistent negative host effects, and provides for future study into the mechanisms of these effects. PMID:26475244

  9. Resistance-induced antibiotic substitution.

    PubMed

    Howard, David H

    2004-06-01

    In many cases, physicians prescribe antibiotics without knowing whether an individual patient is infected with a susceptible or resistant pathogen. As the proportion of resistant organisms in a community increases, physicians substitute away from older-inexpensive drugs to newer, more expensive agents as first line therapy. This paper explores the implications of resistance-induced antibiotic substitution for epidemiological models to predict future resistance levels, efforts to measure the health care costs associated with resistance, and policies to improve physicians' antibiotic prescribing decisions. The extent of resistance-induced substitution in outpatient settings is documented using a data set consisting of observations on initial physician office visits for otitis media in the US controlling for new product introductions and price increases, per prescription antibiotic spending increased by 22% between 1980 and 1996, corresponding to a steep increase in resistance levels over the same period. PMID:15185388

  10. Indications of Coupled Carbon and Iron Cycling at a Hydrocarbon-Contaminated Site from Time-Lapse Magnetic Susceptibility (MS) Profiles

    NASA Astrophysics Data System (ADS)

    Lund, A.; Slater, L. D.; Atekwana, E. A.; Rossbach, S.; Ntarlagiannis, D.; Bekins, B. A.

    2015-12-01

    Magnetic susceptibility (MS) data acquired at hydrocarbon contaminated sites have documented enhanced MS within the smear zone (zone of water table fluctuation at hydrocarbon contaminated location) coincident with the free phase (mobile or free liquids moving down through the unsaturated zone independent of the direction of flow of the groundwater or surface water) hydrocarbon plume These studies suggest that magnetic susceptibility can be used as a tool to: (1) infer regions of hydrocarbon contamination, and (2) investigate intrinsic bioremediation by iron reducing bacteria. We performed a campaign of time-lapse MS monitoring at the National Crude Oil Spill Fate and Natural Attenuation Research Site (Bemidji, MN) between July 2011 and August 2015. This highly instrumented site has multiple boreholes installed through the free phase, dissolved phase and uncontaminated portions of the aquifer impacted by an oil spill resulting from a pipeline rupture in 1979. Magnetic susceptibility (MS) data acquired in 2011 showed that MS values in the smear zone are higher than in the dissolved phase plume and background, leading to the hypothesis that MS measurements could be used to monitor the long-term progress of biodegradation at the site. However, repeated MS data acquired in 2014 and 2015 showed strong changes in the character of the MS signal in the smear zone with multiple free phase contamination locations showing a strong suppression of the signal relative to that observed in 2011. Other locations in the dissolved phase of the plume show evidence for vertical migration of the zone of enhanced MS, possibly due to changes in the redox profiles driven by hydrology. Such changes in the MS signal are hypothesized to result from either variations in Fe(II)/Fe(III) ratios in the magnetite or changes in the magnetite concentration associated with coupled carbon and iron biogeochemistry. This work is generating a unique time-lapse geophysical dataset providing information on

  11. Bacterial profile of urinary tract infection and antimicrobial susceptibility pattern among pregnant women attending at Antenatal Clinic in Dil Chora Referral Hospital, Dire Dawa, Eastern Ethiopia

    PubMed Central

    Derese, Behailu; Kedir, Haji; Teklemariam, Zelalem; Weldegebreal, Fitsum; Balakrishnan, Senthilkumar

    2016-01-01

    Purpose The aim of this study was to determine the bacterial profile of urinary tract infection (UTI) and antimicrobial susceptibility pattern among pregnant women attending at antenatal clinic in Dil Chora Referral Hospital, Dire Dawa, Eastern Ethiopia. Patients and methods An institutional-based cross-sectional study was conducted from February 18, 2015 to March 25, 2015. Clean-catch midstream urine specimens were collected from 186 pregnant women using sterile containers. Then, culture and antimicrobial susceptibility tests were performed by standard disk diffusion method. Patient information was obtained using pretested structured questionnaire. Data were entered and cleaned using EpiData Version 3 and then exported to Statistical Package for Social Science (Version 16) for further analysis. Results The prevalence of significant bacteriuria was 14%. Gram-negative bacteria were more prevalent (73%). Escherichia coli (34.6%), coagulase-negative staphylococci (19.2%), Pseudomonas aeruginosa (15.4%), and Klebsiella spp. (11.5%) were common bacterial isolates, where most of them were resistant against ampicillin, amoxicillin, tetracycline, trimethoprim–sulfamethoxazole, and chloramphenicol. Multidrug resistance (resistance in ≥2 drugs) was seen in 100% of the isolated bacteria. A majority of the bacterial isolates were sensitive to ciprofloxacin, ceftriaxone, erythromycin, and gentamicin. Conclusion This study found a number of bacterial isolates with very high resistance to the commonly prescribed drugs from pregnant women with and without symptoms of UTI. Therefore, the early routine detection of causative agents of UTI and determining their drug susceptibility pattern are important for pregnant women to avoid complications in mother and fetus. Ciprofloxacin, ceftriaxone, gentamicin, and erythromycin can be used with great care for the empirical treatment of UTI. PMID:26937197

  12. In utero exposure of rats to high-fat diets perturbs gene expression profiles and cancer susceptibility of prepubertal mammary glands.

    PubMed

    Govindarajah, Vinothini; Leung, Yuet-Kin; Ying, Jun; Gear, Robin; Bornschein, Robert L; Medvedovic, Mario; Ho, Shuk-Mei

    2016-03-01

    Human studies suggest that high-fat diets (HFDs) increase the risk of breast cancer. The 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary carcinogenesis rat model is commonly used to evaluate the effects of lifestyle factors such as HFD on mammary tumor risk. Past studies focused primarily on the effects of continuous maternal exposure on the risk of offspring at the end of puberty (PND50). We assessed the effects of prenatal HFD exposure on cancer susceptibility in prepubertal mammary glands and identified key gene networks associated with such disruption. During pregnancy, dams were fed AIN-93G-based diets with isocaloric high olive oil, butterfat or safflower oil. The control group received AIN-93G. Female offspring were treated with DMBA on PND21. However, a significant increase in tumor volume and a trend of shortened tumor latency were observed in rats with HFD exposure against the controls (P=.048 and P=.067, respectively). Large-volume tumors harbored carcinoma in situ. Transcriptome profiling identified 43 differentially expressed genes in the mammary glands of the HFBUTTER group as compared with control. Rapid hormone signaling was the most dysregulated pathway. The diet also induced aberrant expression of Dnmt3a, Mbd1 and Mbd3, consistent with potential epigenetic disruption. Collectively, these findings provide the first evidence supporting susceptibility of prepubertal mammary glands to DMBA-induced tumorigenesis that can be modulated by dietary fat that involves aberrant gene expression and likely epigenetic dysregulation. PMID:26895667

  13. Antibiotic resistance: from Darwin to Lederberg to Keynes.

    PubMed

    Amábile-Cuevas, Carlos F

    2013-04-01

    The emergence and spread of antibiotic-resistant bacteria reflects both, a gradual, completely Darwinian evolution, which mostly yields slight decreases in antibiotic susceptibility, along with phenotypes that are not precisely characterized as "resistance"; and sudden changes, from full susceptibility to full resistance, which are driven by a vast array of horizontal gene transfer mechanisms. Antibiotics select for more than just antibiotic resistance (i.e., increased virulence and enhanced gene exchange abilities); and many non-antibiotic agents or conditions select for or maintain antibiotic resistance traits as a result of a complex network of underlying and often overlapping mechanisms. Thus, the development of new antibiotics and thoughtful, integrated anti-infective strategies is needed to address the immediate and long-term threat of antibiotic resistance. Since the biology of resistance is complex, these new drugs and strategies will not come from free-market forces, or from "incentives" for pharmaceutical companies. PMID:23046150

  14. Antibiotic-Resistant Bacteria Are Major Threats of Otitis Media in Wollo Area, Northeastern Ethiopia: A Ten-Year Retrospective Analysis

    PubMed Central

    Argaw-Denboba, Ayele; Abejew, Asrat Agalu; Mekonnen, Alemayehu Gashaw

    2016-01-01

    Antibiotic resistance is an increasingly serious threat to human health that needs an urgent action. The aim of this study was to determine the prevalence and antibiotic susceptibility profiles of bacteria isolated from patient ear discharges suspected of otitis media. A retrospective analysis was performed using culture and antibiotic susceptibility test results of 1225 patients who visited Dessie Regional Health Research Laboratory from 2001 to 2011. Results showed a strong association (P < 0.001) between age and the risk of acquiring middle ear infection. The predominant bacterial isolates were Proteus spp. (28.8%), Staphylococcus aureus (23.7%), and Pseudomonas spp. (17.2%). Most of the isolated bacteria showed high resistance to ampicillin (88.5%), ceftriaxone (84.5%), amoxicillin (81.9%), and tetracycline (74.5%). About 72.5% of Proteus spp. and 62.2% of Pseudomonas spp. have developed resistance to one and more antibiotics used to treat them. This retrospective study also revealed the overall antibiotic resistance rate of bacterial isolates was increased nearly twofold (P = 0.001) over the last decade. Relatively, ciprofloxacin and gentamicin were the most effective antibiotics against all the isolates. In conclusion, antibiotic-resistant bacteria are alarmingly increasing in Wollo area, northeastern Ethiopia, and becoming a major public health problem in the management of patients with middle ear infection. PMID:26904125

  15. Transcriptome Profiling of Human Ulcerative Colitis Mucosa Reveals Altered Expression of Pathways Enriched in Genetic Susceptibility Loci

    PubMed Central

    Li, Jin; Zhu, Junfei; Gu, Mengnan; Baldassano, Robert N.; Grant, Struan F. A.; Hakonarson, Hakon

    2014-01-01

    Human colonic mucosa altered by inflammation due to ulcerative colitis (UC) displays a drastically altered pattern of gene expression compared with healthy tissue. We aimed to understand the underlying molecular pathways influencing these differences by analyzing three publically-available, independently-generated microarray datasets of gene expression from endoscopic biopsies of the colon. Gene set enrichment analysis (GSEA) revealed that all three datasets share 87 gene sets upregulated in UC lesions and 8 gene sets downregulated (false discovery rate <0.05). The upregulated pathways were dominated by gene sets involved in immune function and signaling, as well as the control of mitosis. We applied pathway analysis to genotype data derived from genome-wide association studies (GWAS) of UC, consisting of 5,584 cases and 11,587 controls assembled from eight European-ancestry cohorts. The upregulated pathways derived from the gene expression data showed a highly significant overlap with pathways derived from the genotype data (33 of 56 gene sets, hypergeometric P = 1.49×10–19). This study supports the hypothesis that heritable variation in gene expression as measured by GWAS signals can influence key pathways in the development of disease, and that comparison of genetic susceptibility loci with gene expression signatures can differentiate key drivers of inflammation from secondary effects on gene expression of the inflammatory process. PMID:24788701

  16. Probiotics and Antibiotic-Associated Diarrhea and Clostridium difficile Infection

    NASA Astrophysics Data System (ADS)

    Surawicz, Christina M.

    Diarrhea is a common side effect of antibiotics. Antibiotics can cause diarrhea in 5-25% of individuals who take them but its occurrence is unpredictable. Diarrhea due to antibiotics is called antibiotic-associated diarrhea (AAD). Diarrhea may be mild and resolve when antibiotics are discontinued, or it may be more severe. The most severe form of AAD is caused by overgrowth of Clostridium difficile which can cause severe diarrhea, colitis, pseudomembranous colitis, or even fatal toxic megacolon. Rates of diarrhea vary with the specific antibiotic as well as with the individual susceptibility.

  17. Long-term evaluation of the antimicrobial susceptibility and microbial profile of subgingival biofilms in individuals with aggressive periodontitis

    PubMed Central

    Lourenço, Talita Gomes Baêta; Heller, Débora; do Souto, Renata Martins; Silva-Senem, Mayra Xavier e; Varela, Victor Macedo; Torres, Maria Cynesia Barros; Feres-Filho, Eduardo Jorge; Colombo, Ana Paula Vieira

    2015-01-01

    This study evaluates the antimicrobial susceptibility and composition of subgingival biofilms in generalized aggressive periodontitis (GAP) patients treated using mechanical/antimicrobial therapies, including chlorhexidine (CHX), amoxicillin (AMX) and metronidazole (MET). GAP patients allocated to the placebo (C, n = 15) or test group (T, n = 16) received full-mouth disinfection with CHX, scaling and root planning, and systemic AMX (500 mg)/MET (250 mg) or placebos. Subgingival plaque samples were obtained at baseline, 3, 6, 9 and 12 months post-therapy from 3–4 periodontal pockets, and the samples were pooled and cultivated under anaerobic conditions. The minimum inhibitory concentrations (MICs) of AMX, MET and CHX were assessed using the microdilution method. Bacterial species present in the cultivated biofilm were identified by checkerboard DNA-DNA hybridization. At baseline, no differences in the MICs between groups were observed for the 3 antimicrobials. In the T group, significant increases in the MICs of CHX (p < 0.05) and AMX (p < 0.01) were detected during the first 3 months; however, the MIC of MET decreased at 12 months (p < 0.05). For several species, the MICs significantly changed over time in both groups, i.e., Streptococci MICs tended to increase, while for several periodontal pathogens, the MICs diminished. A transitory increase in the MIC of the subgingival biofilm to AMX and CHX was observed in GAP patients treated using enhanced mechanical therapy with topical CHX and systemic AMX/MET. Both protocols presented limited effects on the cultivable subgingival microbiota. PMID:26273264

  18. Long-term evaluation of the antimicrobial susceptibility and microbial profile of subgingival biofilms in individuals with aggressive periodontitis.

    PubMed

    Lourenço, Talita Gomes Baêta; Heller, Débora; do Souto, Renata Martins; Silva-Senem, Mayra Xavier E; Varela, Victor Macedo; Torres, Maria Cynesia Barros; Feres-Filho, Eduardo Jorge; Colombo, Ana Paula Vieira

    2015-06-01

    This study evaluates the antimicrobial susceptibility and composition of subgingival biofilms in generalized aggressive periodontitis (GAP) patients treated using mechanical/antimicrobial therapies, including chlorhexidine (CHX), amoxicillin (AMX) and metronidazole (MET). GAP patients allocated to the placebo (C, n = 15) or test group (T, n = 16) received full-mouth disinfection with CHX, scaling and root planning, and systemic AMX (500 mg)/MET (250 mg) or placebos. Subgingival plaque samples were obtained at baseline, 3, 6, 9 and 12 months post-therapy from 3-4 periodontal pockets, and the samples were pooled and cultivated under anaerobic conditions. The minimum inhibitory concentrations (MICs) of AMX, MET and CHX were assessed using the microdilution method. Bacterial species present in the cultivated biofilm were identified by checkerboard DNA-DNA hybridization. At baseline, no differences in the MICs between groups were observed for the 3 antimicrobials. In the T group, significant increases in the MICs of CHX (p < 0.05) and AMX (p < 0.01) were detected during the first 3 months; however, the MIC of MET decreased at 12 months (p < 0.05). For several species, the MICs significantly changed over time in both groups, i.e., Streptococci MICs tended to increase, while for several periodontal pathogens, the MICs diminished. A transitory increase in the MIC of the subgingival biofilm to AMX and CHX was observed in GAP patients treated using enhanced mechanical therapy with topical CHX and systemic AMX/MET. Both protocols presented limited effects on the cultivable subgingival microbiota. PMID:26273264

  19. Surveillance of antibiotic resistance

    PubMed Central

    Johnson, Alan P.

    2015-01-01

    Surveillance involves the collection and analysis of data for the detection and monitoring of threats to public health. Surveillance should also inform as to the epidemiology of the threat and its burden in the population. A further key component of surveillance is the timely feedback of data to stakeholders with a view to generating action aimed at reducing or preventing the public health threat being monitored. Surveillance of antibiotic resistance involves the collection of antibiotic susceptibility test results undertaken by microbiology laboratories on bacteria isolated from clinical samples sent for investigation. Correlation of these data with demographic and clinical data for the patient populations from whom the pathogens were isolated gives insight into the underlying epidemiology and facilitates the formulation of rational interventions aimed at reducing the burden of resistance. This article describes a range of surveillance activities that have been undertaken in the UK over a number of years, together with current interventions being implemented. These activities are not only of national importance but form part of the international response to the global threat posed by antibiotic resistance. PMID:25918439

  20. Aging Increases Susceptibility to High Fat Diet-Induced Metabolic Syndrome in C57BL/6 Mice: Improvement in Glycemic and Lipid Profile after Antioxidant Therapy

    PubMed Central

    Nunes-Souza, Valéria; César-Gomes, Cheila Juliana; Da Fonseca, Lucas José Sá; Guedes, Glaucevane Da Silva; Smaniotto, Salete; Rabelo, Luíza Antas

    2016-01-01

    Nonalcoholic fatty liver disease (NAFLD) has been considered a novel component of the metabolic syndrome (MetS), with the oxidative stress participating in its progression. This study aimed to evaluate the metabolic profile in young and old mice with MetS, and the effects of apocynin and tempol on glycemic and lipid parameters. Young and old C57BL/6 mice with high fat diet- (HFD-) induced MetS received apocynin and tempol 50 mg·kg−1/day in their drinking water for 10 weeks. After HFD, the young group showed elevated fasting glucose, worsened lipid profile in plasma, steatosis, and hepatic lipid peroxidation. Nevertheless, the old group presented significant increase in fasting insulin levels, insulin resistance, plasma and hepatic lipid peroxidation, and pronounced steatosis. The hepatic superoxide dismutase and catalase activity did not differ between the groups. Tempol and apocynin seemed to prevent hepatic lipid deposition in both groups. Furthermore, apocynin improved glucose tolerance and insulin sensitivity in old mice. In summary, old mice are more susceptible to HFD-induced metabolic changes than their young counterparts. Also, the antioxidant therapy improved insulin sensitivity and glucose tolerance, and in addition, apocynin se