PATHOGENICITY OF BIOFILM BACTERIA

EPA Science Inventory

There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

The prevalence and distribution of indicators of fecal contamination in the sand from beaches of Oran coast

NASA Astrophysics Data System (ADS)

Messaoui, N.; Matallah-Boutiba, A.; Boutiba, Z.

2017-02-01

The microbiological quality of water at public bathing beaches is regularly monitored using fecal indicator bacteria (FIB) as a surrogate for the presence of human sewage and pathogens. The common feature of all these routine screening procedures is that the primary analysis is for indicator organisms rather than the pathogens that might cause concern. Indicator organisms are bacteria such as non-specific coliforms, Escherichia coli and Pseudomonas aeruginosa that are very commonly found in the human or animal gut and which, if detected, may suggest the presence of sewage. Indicator organisms are used because even when a person is infected with more pathogenic bacteria, they will still be excreting many millions times more indicator organisms than pathogens. It is therefore reasonable to surmise that if indicator organism levels are low, then pathogen levels will be very much lower or absent. Judgments as to suitability of water for use are based on very extensive precedents and relate to the probability of any sample population of bacteria being able to be infective at a reasonable statistical level of confidence. Exposure to FIB and associated pathogens may also occur through contact with contaminated beach sand, but no standards limiting levels of microbes in sand or required monitoring program has been established. As a result, the factors affecting FIB and pathogen survival/persistence in sand remain largely unstudied. A possible contamination of the sand by bacterial communities could be a source of transmission of certain pathogenic bacteria. The goal of this study was to look for a presence of certain bacteria that could be a source of illness to swimmers and compare the different levels of contamination between beach sand and sea water in four sites along the Western Oranian coast. First analysis were made during the dry season and rainy season from December 2010 to June 2012 to estimate fecal coliforms, Pseudomonas spp and total germs levels. E.coli and Enterococcus.ssp levels were estimated from September 2012 to June 2015. Highest levels of bacterial flora were detected in dry sand beach in impacted locations for almost all the period of studies. PCR or molecular biology techniques can be used in order to show the presence of pathogenic strains of E. coli like E.coli O157:H7.

[Clinical analysis for patients with continuous ambulatory peritoneal dialysis associated peritonitis].

PubMed

Liu, Jian; Huang, Xun; Liu, Yao; Xu, Hui; Gong, Rui'e; Li, Chunhui

2016-12-28

To analyze the clinical characteristics of continuous ambulatory peritoneal dialysis (CAPD) associated peritonitis in the tertiary hospitals and to discuss the preventive and therapeutic strategy.
 Methods: The clinical characteristics, pathogens, resistance and outcomes of 126 CAPD associated peritonitis in 104 patients from Jan, 2013 to June, 2016, were retrospectively analyzed.
 Results: Among the patients, the incidence rates of abdominal pain, fever, diarrhea and emesis were 104 (82.54%), 56 (44.44%), 49 (38.89%), and 31 (23.60%), respectively. Among them, 88 patients suffered peritonitis once, other 16 patients suffered multiple peritonitis or recurrent peritonitis for 38 times. Among the 38 times, the numbers for recurrent, repeated or catheter-associated peritonitis were 2, 2, or 3, respectively. Peritoneal fluids from 103 cases were cultured, and 64 cases were positive in bacteria, with a rate of 62.14%. A total of 70 strains of bacteria were separated, including 42 strains of gram-positive bacteria, 21 strains of gram-negative bacteria, and 7 strains of fungus. The most common gram-positive pathogens were Staphylococcus epidermidis, Enterococcus faecalis and Staphylococcus haemolyticus, while Escherichia coli, Klebsiella pneumoniae and Klebsiella pneumoniae were the most common gram-negative bacteria. Candida albicans was the major fungal pathogens. Gram-positive cocci showed resistance to gentamycin, levofloxacin, moxifloxacin, vancomycin and linezolid, with a rate at 20.00%, 36.11%, 5%, 0%, and 0%, respectively. The gram-negative bacilli were resistent to cefoperazone/sulbactam, gentamycin, cephazolin, and ceftazidime, with a rate at 6.25%, 10.53%, 64.29%, and 15.38%, respectively. There were no imipenem, amikacin, piperacillin/tazobactam-resistant strains were found.
 Conclusion: The most common pathogen causing CAPD associated peritonitis is gram-positive bacteria. It is crucial to take the anti-infection therapy for CAPD associated peritonitis early. The positive rates for bacterial culture need to be enhanced through improvement of methods. At the same time, doctors could improve the outcome of CAPD associated peritonitis by adjusting the medication according to the drug sensitivity results.

EXPLORATORY OCCURRENCE OF HETEROTROPHIC BACTERIA IN POTABLE WATER

EPA Science Inventory

Heterotrophic bacteria (HPC) are common to community distribution systems conveying treated drinking water to consumers. There are known opportunistic pathogens among these organisms, for example some Legionella and some Aeromonas strains; and there may be others of which we are ...

Interrelationships of food safety and plant pathology: the life cycle of human pathogens on plants.

PubMed

Barak, Jeri D; Schroeder, Brenda K

2012-01-01

Bacterial food-borne pathogens use plants as vectors between animal hosts, all the while following the life cycle script of plant-associated bacteria. Similar to phytobacteria, Salmonella, pathogenic Escherichia coli, and cross-domain pathogens have a foothold in agricultural production areas. The commonality of environmental contamination translates to contact with plants. Because of the chronic absence of kill steps against human pathogens for fresh produce, arrival on plants leads to persistence and the risk of human illness. Significant research progress is revealing mechanisms used by human pathogens to colonize plants and important biological interactions between and among bacteria in planta. These findings articulate the difficulty of eliminating or reducing the pathogen from plants. The plant itself may be an untapped key to clean produce. This review highlights the life of human pathogens outside an animal host, focusing on the role of plants, and illustrates areas that are ripe for future investigation.

Insect symbiotic bacteria harbour viral pathogens for transovarial transmission.

PubMed

Jia, Dongsheng; Mao, Qianzhuo; Chen, Yong; Liu, Yuyan; Chen, Qian; Wu, Wei; Zhang, Xiaofeng; Chen, Hongyan; Li, Yi; Wei, Taiyun

2017-03-06

Many insects, including mosquitoes, planthoppers, aphids and leafhoppers, are the hosts of bacterial symbionts and the vectors for transmitting viral pathogens 1-3 . In general, symbiotic bacteria can indirectly affect viral transmission by enhancing immunity and resistance to viruses in insects 3-5 . Whether symbiotic bacteria can directly interact with the virus and mediate its transmission has been unknown. Here, we show that an insect symbiotic bacterium directly harbours a viral pathogen and mediates its transovarial transmission to offspring. We observe rice dwarf virus (a plant reovirus) binding to the envelopes of the bacterium Sulcia, a common obligate symbiont of leafhoppers 6-8 , allowing the virus to exploit the ancient oocyte entry path of Sulcia in rice leafhopper vectors. Such virus-bacterium binding is mediated by the specific interaction of the viral capsid protein and the Sulcia outer membrane protein. Treatment with antibiotics or antibodies against Sulcia outer membrane protein interferes with this interaction and strongly prevents viral transmission to insect offspring. This newly discovered virus-bacterium interaction represents the first evidence that a viral pathogen can directly exploit a symbiotic bacterium for its transmission. We believe that such a model of virus-bacterium communication is a common phenomenon in nature.

Characterization of Bacteria in Nigerian Yogurt as Promising Alternative to Antibiotics in Gastrointestinal Infections.

PubMed

Ayeni, Anthony Opeyemi; Ruppitsch, Werner; Ayeni, Funmilola Abidemi

2018-03-14

Gastrointestinal infections are endemic in Nigeria and several factors contribute to their continual survival, including bacterial resistance to commonly used antibiotics. Nigerian yogurts do not include probiotics, and limited information is available about the antimicrobial properties of the fermenters in the yogurt against gastrointestinal pathogens. Therefore, the antimicrobial potentials of bacteria in Nigeria-produced yogurts against intestinal pathogens were investigated in this study. Viable counts of lactic acid bacteria (LAB) in 15 brands of yogurt were enumerated and the bacteria identified by partial sequencing of 16S rRNA gene. Susceptibility of the gastrointestinal pathogens (Salmonella, Shigella and E. coli ) to antibiotics by disc diffusion method, to viable LAB by the agar overlay method, and to the cell-free culture supernatant (CFCS) of the LAB were investigated. Co-culture analysis of LAB and pathogens were also done. Viable counts of 1.5 × 10 11 cfu/ml were observed in some yogurt samples. Two genera were identified: Lactobacillus (70.7%) and Acetobacter (29.3%). The Lactobacillus species reduced multidrug-resistant gastrointestinal pathogens by 4 to 5 log while the zones of inhibition ranged between 11 and 23. The Lactobacillus and Acetobacter strains examined displayed good activities against the multidrug-resistant tested pathogens. This is the first report of antimicrobial activities of acetic acid bacteria isolated from yogurt in Nigeria.

Change Is Good: Variations in Common Biological Mechanisms in the Epsilonproteobacterial Genera Campylobacter and Helicobacter

PubMed Central

Gilbreath, Jeremy J.; Cody, William L.; Merrell, D. Scott; Hendrixson, David R.

2011-01-01

Summary: Microbial evolution and subsequent species diversification enable bacterial organisms to perform common biological processes by a variety of means. The epsilonproteobacteria are a diverse class of prokaryotes that thrive in diverse habitats. Many of these environmental niches are labeled as extreme, whereas other niches include various sites within human, animal, and insect hosts. Some epsilonproteobacteria, such as Campylobacter jejuni and Helicobacter pylori, are common pathogens of humans that inhabit specific regions of the gastrointestinal tract. As such, the biological processes of pathogenic Campylobacter and Helicobacter spp. are often modeled after those of common enteric pathogens such as Salmonella spp. and Escherichia coli. While many exquisite biological mechanisms involving biochemical processes, genetic regulatory pathways, and pathogenesis of disease have been elucidated from studies of Salmonella spp. and E. coli, these paradigms often do not apply to the same processes in the epsilonproteobacteria. Instead, these bacteria often display extensive variation in common biological mechanisms relative to those of other prototypical bacteria. In this review, five biological processes of commonly studied model bacterial species are compared to those of the epsilonproteobacteria C. jejuni and H. pylori. Distinct differences in the processes of flagellar biosynthesis, DNA uptake and recombination, iron homeostasis, interaction with epithelial cells, and protein glycosylation are highlighted. Collectively, these studies support a broader view of the vast repertoire of biological mechanisms employed by bacteria and suggest that future studies of the epsilonproteobacteria will continue to provide novel and interesting information regarding prokaryotic cellular biology. PMID:21372321

Change is good: variations in common biological mechanisms in the epsilonproteobacterial genera Campylobacter and Helicobacter.

PubMed

Gilbreath, Jeremy J; Cody, William L; Merrell, D Scott; Hendrixson, David R

2011-03-01

Microbial evolution and subsequent species diversification enable bacterial organisms to perform common biological processes by a variety of means. The epsilonproteobacteria are a diverse class of prokaryotes that thrive in diverse habitats. Many of these environmental niches are labeled as extreme, whereas other niches include various sites within human, animal, and insect hosts. Some epsilonproteobacteria, such as Campylobacter jejuni and Helicobacter pylori, are common pathogens of humans that inhabit specific regions of the gastrointestinal tract. As such, the biological processes of pathogenic Campylobacter and Helicobacter spp. are often modeled after those of common enteric pathogens such as Salmonella spp. and Escherichia coli. While many exquisite biological mechanisms involving biochemical processes, genetic regulatory pathways, and pathogenesis of disease have been elucidated from studies of Salmonella spp. and E. coli, these paradigms often do not apply to the same processes in the epsilonproteobacteria. Instead, these bacteria often display extensive variation in common biological mechanisms relative to those of other prototypical bacteria. In this review, five biological processes of commonly studied model bacterial species are compared to those of the epsilonproteobacteria C. jejuni and H. pylori. Distinct differences in the processes of flagellar biosynthesis, DNA uptake and recombination, iron homeostasis, interaction with epithelial cells, and protein glycosylation are highlighted. Collectively, these studies support a broader view of the vast repertoire of biological mechanisms employed by bacteria and suggest that future studies of the epsilonproteobacteria will continue to provide novel and interesting information regarding prokaryotic cellular biology.

A novel, multiplex, real-time PCR-based approach for the detection of the commonly occurring pathogenic fungi and bacteria.

PubMed

Horváth, Ádám; Pető, Zoltán; Urbán, Edit; Vágvölgyi, Csaba; Somogyvári, Ferenc

2013-12-23

Polymerase chain reaction (PCR)-based techniques are widely used to identify fungal and bacterial infections. There have been numerous reports of different, new, real-time PCR-based pathogen identification methods although the clinical practicability of such techniques is not yet fully clarified.The present study focuses on a novel, multiplex, real-time PCR-based pathogen identification system developed for rapid differentiation of the commonly occurring bacterial and fungal causative pathogens of bloodstream infections. A multiplex, real-time PCR approach is introduced for the detection and differentiation of fungi, Gram-positive (G+) and Gram-negative (G-) bacteria. The Gram classification is performed with the specific fluorescence resonance energy transfer (FRET) probes recommended for LightCycler capillary real-time PCR. The novelty of our system is the use of a non-specific SYBR Green dye instead of labelled anchor probes or primers, to excite the acceptor dyes on the FRET probes. In conjunction with this, the use of an intercalating dye allows the detection of fungal amplicons.With the novel pathogen detection system, fungi, G + and G- bacteria in the same reaction tube can be differentiated within an hour after the DNA preparation via the melting temperatures of the amplicons and probes in the same tube. This modified FRET technique is specific and more rapid than the gold-standard culture-based methods. The fact that fungi, G + and G- bacteria were successfully identified in the same tube within an hour after the DNA preparation permits rapid and early evidence-based management of bloodstream infections in clinical practice.

Bacterial pathogens of the bovine respiratory disease complex.

PubMed

Griffin, Dee; Chengappa, M M; Kuszak, Jennifer; McVey, D Scott

2010-07-01

Pneumonia caused by the bacterial pathogens discussed in this article is the most significant cause of morbidity and mortality of the BRDC. Most of these infectious bacteria are not capable of inducing significant disease without the presence of other predisposing environmental factors, physiologic stressors, or concurrent infections. Mannheimia haemolytica is the most common and serious of these bacterial agents and is therefore also the most highly characterized. There are other important bacterial pathogens of BRD, such as Pasteurella multocida, Histophulus somni, and Mycoplasma bovis. Mixed infections with these organisms do occur. These pathogens have unique and common virulence factors but the resulting pneumonic lesions may be similar. Although the amount and quality of research associated with BRD has increased, vaccination and therapeutic practices are not fully successful. A greater understanding of the virulence mechanisms of the infecting bacteria and pathogenesis of pneumonia, as well as the characteristics of the organisms that allow tissue persistence, may lead to improved management, therapeutics, and vaccines. Copyright 2010 Elsevier Inc. All rights reserved.

Potential Role of Diploscapter sp. Strain LKC25, a Bacterivorous Nematode from Soil, as a Vector of Food-Borne Pathogenic Bacteria to Preharvest Fruits and Vegetables

PubMed Central

Gibbs, Daunte S.; Anderson, Gary L.; Beuchat, Larry R.; Carta, Lynn K.; Williams, Phillip L.

2005-01-01

Diploscapter, a thermotolerant, free-living soil bacterial-feeding nematode commonly found in compost, sewage, and agricultural soil in the United States, was studied to determine its potential role as a vehicle of Salmonella enterica serotype Poona, enterohemorrhagic Escherichia coli O157:H7, and Listeria monocytogenes in contaminating preharvest fruits and vegetables. The ability of Diploscapter sp. strain LKC25 to survive on agar media, in cow manure, and in composted turkey manure and to be attracted to, ingest, and disperse food-borne pathogens inoculated into soil or a mixture of soil and composted turkey manure was investigated. Diploscapter sp. strain LKC25 survived and reproduced in lawns of S. enterica serotype Poona, E. coli O157:H7, and L. monocytogenes on agar media and in cow manure and composted turkey manure. Attraction of Diploscapter sp. strain LKC25 to colonies of pathogenic bacteria on tryptic soy agar within 10, 20, 30, and 60 min and 24 h was determined. At least 85% of the worms initially placed 0.5 to 1 cm away from bacterial colonies migrated to the colonies within 1 h. Within 24 h, ≥90% of the worms were embedded in colonies. The potential of Diploscapter sp. strain LKC25 to shed pathogenic bacteria after exposure to bacteria inoculated into soil or a mixture of soil and composted turkey manure was investigated. Results indicate that Diploscapter sp. strain LKC25 can shed pathogenic bacteria after exposure to pathogens in these milieus. They also demonstrate its potential to serve as a vector of food-borne pathogenic bacteria in soil, with or without amendment with compost, to the surface of preharvest fruits and vegetables in contact with soil. PMID:15870330

Genus Distribution of Bacteria and Fungi Associated with Keratitis in a Large Eye Center Located in Southern China.

PubMed

Lin, Lixia; Lan, Weizhong; Lou, Bingsheng; Ke, Hongmin; Yang, Yuanzhe; Lin, Xiaofeng; Liang, Lingyi

2017-04-01

To investigate the genus distribution of bacteria and fungi associated with keratitis in a large eye center located in Southern China and to compare the results with existing data from other areas in China. All results of corneal microbiological examinations from 2009 to 2013 of patients who had been clinically diagnosed with bacterial or fungal keratitis were obtained chronologically and anonymously from the microbiology database at Zhongshan Ophthalmic Center. Smear/culture data were reviewed and analyzed. Antibiotic resistance of the harvested bacteria was also evaluated. Of 2973 samples, the microbial detection rate was 46.05%; in which 759 eyes (25.5%) were positive for bacteria, 796 eyes (26.8%) were positive for fungi, and 186 eyes (6.3%) were co-infected with both fungi and bacteria. The most common type of bacteria isolated was Staphylococcus epidermidis (31.9%), followed by Pseudomonas aeruginosa (12.4%). The most common type of fungus was Fusarium species (29.3%), followed by Aspergillus species (24.1%). For the bacteria harvested, mean antibiotic resistance was chloromycetin (34.6%), cephalosporins (20.0%), fluoroquinolones (18.6%), and aminoglycosides (10.5%). The genus distribution of organisms detected in keratitis cases in the largest eye center located in Southern China differs from those in other areas in China. In Southern China during the time period studied, S. epidermidis and Fusarium sp. were the most common pathogens of infectious keratitis. Monitoring the changing trend of pathogens as well as antibiotic resistance are warranted.

Antibiotic resistance increases with local temperature

NASA Astrophysics Data System (ADS)

MacFadden, Derek R.; McGough, Sarah F.; Fisman, David; Santillana, Mauricio; Brownstein, John S.

2018-06-01

Bacteria that cause infections in humans can develop or acquire resistance to antibiotics commonly used against them1,2. Antimicrobial resistance (in bacteria and other microbes) causes significant morbidity worldwide, and some estimates indicate the attributable mortality could reach up to 10 million by 20502-4. Antibiotic resistance in bacteria is believed to develop largely under the selective pressure of antibiotic use; however, other factors may contribute to population level increases in antibiotic resistance1,2. We explored the role of climate (temperature) and additional factors on the distribution of antibiotic resistance across the United States, and here we show that increasing local temperature as well as population density are associated with increasing antibiotic resistance (percent resistant) in common pathogens. We found that an increase in temperature of 10 °C across regions was associated with an increases in antibiotic resistance of 4.2%, 2.2%, and 2.7% for the common pathogens Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. The associations between temperature and antibiotic resistance in this ecological study are consistent across most classes of antibiotics and pathogens and may be strengthening over time. These findings suggest that current forecasts of the burden of antibiotic resistance could be significant underestimates in the face of a growing population and climate change4.

[Analysis of pathogenic bacteria and drug resistance in neonatal purulent meningitis].

PubMed

Zhu, Minli; Hu, Qianhong; Mai, Jingyun; Lin, Zhenlang

2015-01-01

To study the clinical characteristics, pathogenic bacteria, and antibiotics resistance of neonatal purulent meningitis in order to provide the guide for early diagnosis and appropriate treatment. A retrospective review was performed and a total of 112 cases of neonatal purulent meningitis (male 64, female 58) were identified in the neonatal intensive care unit of Yuying Children's Hospital of Wenzhou Medical University seen from January 1, 2004 to December 31, 2013. The clinical information including pathogenic bacterial distribution, drug sensitivity, head imageology and therapeutic outcome were analyzed. Numeration data were shown in ratio and chi square test was applied for group comparison. Among 112 cases, 46 were admitted from 2004 to 2008 and 66 from 2009 to 2013, 23 patients were preterm and 89 were term, 20 were early onset (occurring within 3 days of life) and 92 were late onset meningitis (occurring after 3 days of life). In 62 (55.4%) cases the pathogens were Gram-positive bacteria and in 50 (44.6%) were Gram-negative bacteria. The five most frequently isolated pathogens were Escherichia coli (32 cases, 28.6%), coagulase-negative staphylococcus (CNS, 20 cases, 17.9%), Streptococcus (18 cases, 16.1%, Streptococcus agalactiae 15 cases), Enterococci (13 cases, 11.6%), Staphylococcus aureus (9 cases, 8.0%). Comparison of pathogenic bacterial distribution between 2004-2008 and 2009-2013 showed that Gram-positive bacteria accounted for more than 50% in both period. Escherichia coli was the most common bacterium, followed by Streptococcus in last five years which was higher than the first five years (22.7% (15/66) vs. 6.5% (3/46), χ(2) = 5.278, P < 0.05). Klebsiella pneumoniae was more common isolate in preterm infants than in term infants (13.0% (3/23) vs. 1.1% (1/89), χ(2) = 7.540, P < 0.05). Streptococcus (most were Streptococcus agalactiae) was the most common bacteria in early onset meningitis and higher than those in late onset meningitis (35.0% (7/20) vs. 12.0% (11/92), χ(2) = 4.872, P < 0.05). Drug sensitivity tests showed that all the Gram-positive bacterial isolates were sensitive to linezolid. Staphylococci were resistant to penicillin, and most of them were resistant to erythromycin, oxacillin and cefazolin; 77.8%of CNS isolates were methicillin-resistant staphylococcus. No Streptococcus and Enterococcus faecalis was resistant to penicillin. None of enterococci was resistant to vancomycin. Among the Gram-negative bacterial isolates, more than 40% of Escherichia coli were resistant to commonly used cephalosporins such as cefuroxime, cefotaxime and ceftazidime, and all of them were sensitive to amikacin, cefoperazone sulbactam and imipenem. Isolates of Klebsiella pneumoniae were all resistant to ampicillin, cefuroxime, cefotaxime and ceftazidime, but none of them was resistant to piperacillin tazobactam and imipenem. Of the 112 patients, 69 were cured, 23 improved, 9 uncured and 11 died. There were 47 cases (42.0%) with poor prognosis, they had abnormal head imageology, severe complications and some cases died, 13 of 18 (72.2%) patients with meningitis caused by Streptococcus died. Escherichia coli, CNS and Streptococcus are the predominant pathogens responsible for neonatal purulent meningitis over the past ten years. There were increasing numbers of cases with Streptococcus meningitis which are more common in early onset meningitis with adverse outcome, therefore careful attention should be paid in clinic. Linezolid should be used as a new choice in intractable neonatal purulent meningitis cases caused by gram positive bacteria.

Detection of viruses and atypical bacteria associated with acute respiratory infection of children in Hubei, China.

PubMed

Wu, Zegang; Li, Yan; Gu, Jian; Zheng, Hongyun; Tong, Yongqing; Wu, Qing

2014-02-01

Acute respiratory infection is the major cause of disease and death in children, particularly in developing countries. However, the spectrum of pathogenic viruses and atypical bacteria that exist in many of these countries remains incompletely characterized. The aim of this study was to examine the spectrum of pathogenic viruses and atypical bacteria associated with acute respiratory infection in children under the age of 16. A total of 10 435 serum sera specimens were collected from hospitalized children presenting with acute respiratory infection symptoms. Indirect immunofluorescence assays were performed to detect immunoglobulin M antibodies against nine common pathogens: mycoplasma pneumonia, influenza virus B, respiratory syncytial virus, parainfluenza virus, adenovirus, influenza virus A, legionella pneumophila, coxiella burnetii and chamydophila pneumonia. Of the 10 435 specimens examined, 7046 tested positive for at least one pathogen. Among all of the tested pathogens, mycoplasma pneumonia had the highest detection rate (56.9%). Influenza virus A and influenza virus B epidemics occurred during both winter and summer. The detection rate of respiratory syncytial virus and adenovirus was higher in spring. Cases of mixed infection were more complex: 4136 specimens (39.6%) tested positive for ≥2 pathogens. There were statistically significant difference in detection rates of mycoplasma pneumonia, influenza virus B, respiratory syncytial virus, parainfluenza virus, adenovirus, influenza virus A, legionella pneumophila and chamydophila pneumonia among different age groups (P < 0.05). The most common pathogens causing acute respiratory infection among children in Hubei of China were mycoplasma pneumonia, influenza virus B and respiratory syncytial virus. The detection rates for each pathogen displayed specific seasonal and age group variations. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

Anaerobic Bacteria in Clinical Specimens - Frequent, But a Neglected Lot: A Five Year Experience at a Tertiary Care Hospital.

PubMed

Shenoy, Padmaja Ananth; Vishwanath, Shashidhar; Gawda, Ashwini; Shetty, Seema; Anegundi, Renuka; Varma, Muralidhar; Mukhopadhyay, Chiranjay; Chawla, Kiran

2017-07-01

Anaerobic bacteria which constitute a significant proportion of the normal microbiota also cause variety of infections involving various anatomic sites. Considering the tedious culture techniques with longer turnaround time, anaerobic cultures are usually neglected by clinicians and microbiologists. To study the frequency of isolation of different anaerobic bacteria from various clinical specimens. A retrospective study to analyse the frequency of isolation of different anaerobic bacteria, was conducted over a period of five years from 2011 to 2015 including various clinical specimens submitted to anaerobic division of Microbiology laboratory. Anaerobic bacteria were isolated and identified following standard bacteriological techniques. Pathogenic anaerobes (n=336) were isolated from 278 (12.48%) of overall 2227 specimens processed with an average yield of 1.2 isolates. Anaerobes were isolated as polymicrobial flora with or without aerobic bacterial pathogens in 159 (57.2%) patients. Anaerobic Gram-negative bacilli (140, 41.7%) were the predominant isolates. B. fragilis group (67, 19.9%) were the most commonly isolated anaerobic pathogens. Anaerobes were predominantly isolated from deep seated abscess (23.9%). Pathogenic anaerobes were isolated from various infection sites. Unless culture and susceptibility tests are performed as a routine, true magnitude of antimicrobial resistance among anaerobic pathogens will not be known. Knowledge of the distribution of these organisms may assist in the selection of appropriate empirical therapy for anaerobic infections.

Lipoteichoic Acid (LTA) and Lipopolysaccharides (LPS) from Periodontal Pathogenic Bacteria Facilitate Oncogenic Herpesvirus Infection within Primary Oral Cells

PubMed Central

Dai, Lu; DeFee, Michael R.; Cao, Yueyu; Wen, Jiling; Wen, Xiaofei; Noverr, Mairi C.; Qin, Zhiqiang

2014-01-01

Kaposi’s sarcoma (KS) remains the most common tumor arising in patients with HIV/AIDS, and involvement of the oral cavity represents one of the most common clinical manifestations of this tumor. HIV infection incurs an increased risk for periodontal diseases and oral carriage of a variety of bacteria. Whether interactions involving pathogenic bacteria and oncogenic viruses in the local environment facilitate replication or maintenance of these viruses in the oral cavity remains unknown. In the current study, our data indicate that pretreatment of primary human oral fibroblasts with two prototypical pathogen-associated molecular patterns (PAMPs) produced by oral pathogenic bacteria–lipoteichoic acid (LTA) and lipopolysaccharide (LPS), increase KSHV entry and subsequent viral latent gene expression during de novo infection. Further experiments demonstrate that the underlying mechanisms induced by LTA and/or LPS include upregulation of cellular receptor, increasing production of reactive oxygen species (ROS), and activating intracellular signaling pathways such as MAPK and NF-κB, and all of which are closely associated with KSHV entry or gene expression within oral cells. Based on these findings, we hope to provide the framework of developing novel targeted approaches for treatment and prevention of oral KSHV infection and KS development in high-risk HIV-positive patients. PMID:24971655

Pathogenicity of facultative and obligate anaerobic bacteria in monoculture and combined with either Prevotella intermedia or Prevotella nigrescens.

PubMed

Siqueira, J F; Magalhães, F A; Lima, K C; de Uzeda, M

1998-12-01

The pathogenicity of obligate and facultative anaerobic bacteria commonly found in endodontic infections was tested using a mouse model. The capacity of inducing abscesses was evaluated seven days after subcutaneous injection of the bacteria in pure culture and in combinations with either Prevotella intermedia or Prevotella nigrescens. Nine of the fifteen bacterial strains tested were pathogenic in pure culture. No statistically significant differences were detected between these strains in pure culture and in mixtures with either P. intermedia or P. nigrescens. Synergism between the bacterial strains was only apparent when associating Porphyromonas endodontalis with P. intermedia or P. nigrescens. Histopathological examination of tissue sections from induced abscesses revealed an acute inflammatory reaction, dominated by polymorphonuclear leukocytes. Sections from the control group using sterile medium showed no evidence of inflammatory reaction.

Perception of pathogenic or beneficial bacteria and their evasion of host immunity: pattern recognition receptors in the frontline

PubMed Central

Trdá, Lucie; Boutrot, Freddy; Claverie, Justine; Brulé, Daphnée; Dorey, Stephan; Poinssot, Benoit

2015-01-01

Plants are continuously monitoring the presence of microorganisms to establish an adapted response. Plants commonly use pattern recognition receptors (PRRs) to perceive microbe- or pathogen-associated molecular patterns (MAMPs/PAMPs) which are microorganism molecular signatures. Located at the plant plasma membrane, the PRRs are generally receptor-like kinases (RLKs) or receptor-like proteins (RLPs). MAMP detection will lead to the establishment of a plant defense program called MAMP-triggered immunity (MTI). In this review, we overview the RLKs and RLPs that assure early recognition and control of pathogenic or beneficial bacteria. We also highlight the crucial function of PRRs during plant-microbe interactions, with a special emphasis on the receptors of the bacterial flagellin and peptidoglycan. In addition, we discuss the multiple strategies used by bacteria to evade PRR-mediated recognition. PMID:25904927

Antibacterial activities of metabolites from Platanus occidentalis (American sycamore) against fish pathogenic bacteria

USDA-ARS?s Scientific Manuscript database

One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentall...

Sediment and Fecal Indicator Bacteria Loading in a Mixed Land Use Watershed: Contributions from Suspended and Bed Load Transport

EPA Science Inventory

Water quality studies that quantify sediment and fecal bacteria loading commonly focus on suspended contaminants transported during high flows. Fecal contaminants in bed sediments are typically ignored and need to be considered because of their potential to increase pathogen load...

Surface enhanced raman spectroscopy technique in rapid detection of live and dead salmonella cells

USDA-ARS?s Scientific Manuscript database

Many research proved that Surface Enhanced Raman Spectroscopy (SERS) can detect pathogens rapidly and accurately. In this study, a silver metal substrate was used for the selected common food pathogen Salmonella typhimurium bacteria. Nano silver rods were deposited on a thin titanium coating over t...

Notable Aspects of Glycan-Protein Interactions

PubMed Central

Cohen, Miriam

2015-01-01

This mini review highlights several interesting aspects of glycan-mediated interactions that are common between cells, bacteria, and viruses. Glycans are ubiquitously found on all living cells, and in the extracellular milieu of multicellular organisms. They are known to mediate initial binding and recognition events of both immune cells and pathogens with their target cells or tissues. The host target tissues are hidden under a layer of secreted glycosylated decoy targets. In addition, pathogens can utilize and display host glycans to prevent identification as foreign by the host’s immune system (molecular mimicry). Both the host and pathogens continually evolve. The host evolves to prevent infection and the pathogens evolve to evade host defenses. Many pathogens express both glycan-binding proteins and glycosidases. Interestingly, these proteins are often located at the tip of elongated protrusions in bacteria, or in the leading edge of the cell. Glycan-protein interactions have low affinity and, as a result, multivalent interactions are often required to achieve biologically relevant binding. These enable dynamic forms of adhesion mechanisms, reviewed here, and include rolling (cells), stick and roll (bacteria) or surfacing (viruses). PMID:26340640

The blow fly, Chrysomya megacephala, and the house fly, Musca domestica, as mechanical vectors of pathogenic bacteria in Northeast Thailand.

PubMed

Chaiwong, T; Srivoramas, T; Sueabsamran, P; Sukontason, K; Sanford, M R; Sukontason, K L

2014-06-01

The Oriental latrine fly, Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) and the house fly, Musca domestica L., (Diptera: Muscidae) are synanthropic flies which are adapted to live in close association with human habitations, thereby making them likely mechanical vectors of several pathogens to humans. There were two main aims of this study. The first aim was to determine the prevalence of these two fly species from five types of human habitations including: fresh-food markets, garbage piles, restaurants, school cafeterias and paddy fields, in the Muang Ubon Ratchathani and Warinchamrap districts of Ubon Ratchathani province of Northeast Thailand. Flies collection were conducted monthly from September 2010-October 2011 using a reconstructable funnel trap, containing 1 day-tainted beef offal as bait. A total of 7 750 flies (6 401 C. megacephala and 1 349 M.domestica) were collected. The second aim was to examine the potential of these flies to carry pathogenic bacteria. Bacteria were isolated from 994 individual flies collected using a sweep net (555 C. megacephala and 439 M. domestica). A total of 15 bacterial genera were isolated from the external surfaces, comprising ten genera of gram-negative bacteria and five gram-positive bacteria. The most common bacteria isolated from both species were coagulase-negative staphylococci, followed by Streptococcus group D non-enterococci. Human pathogenic enteric bacteria isolated were Salmonella sp., Shigella sp., Escherichia coli O157:H7, Salmonella typhi, Bacillus sp., and Enterococcus sp., of which S. typhi is the first report of isolation from these fly species. Other human pathogens included Staphylococcus aureus and Pseudomonas aeruginosa. Not only were the number of C. megacephala positive for bacteria significantly higher than for M. domestica, but they were also carrying ~11-12 times greater bacterial load than M. domestica. These data suggest that both fly species should be considered potential mechanical vectors of bacterial pathogens associated with human habitations year-round in this region of Northeast Thailand.

Antimicrobial resistance among aerobic biofilm producing bacteria isolated from chronic wounds in the tertiary care hospitals of Peshawar, Pakistan.

PubMed

Rahim, K; Qasim, M; Rahman, H; Khan, T A; Ahmad, I; Khan, N; Ullah, A; Basit, A; Saleha, S

2016-08-01

Chronic wound infections impose major medical and economic costs on health-care systems, cause significant morbidity, mortality and prolonged hospitalisation. The presence of biofilm producing bacteria in these wounds is considered as an important virulence factor that leads to chronic implications including ulceration. The undertaken study aimed to isolate and identify the biofilm aerobic bacterial pathogens from patients with chronic wound infections, and determine their antibiotics resistance profiles Method: During this study, swab specimens were collected from patients with chronic wounds at teaching hospitals of Peshawar, Pakistan between May 2013 and June 2014. The isolated aerobic bacterial pathogens were identified on the basis of standard cultural characteristics and biochemical tests. Antibiotics resistance profiles of biofilm producing bacteria against selected antibiotics were then determined. Among the chronic wound infections, diabetic foot ulcers were most common 37 (37%), followed by surgical ulcers 27 (27%). Chronic wounds were common in male patients older than 40 years. Among the total 163 isolated bacterial pathogens the most prevalent bacterial species were Pseudomonas aeruginosa 44 (27%), Klebsiella pneumoniae 26 (16%), Staphylococcus species 22 (14%) and Streptococcus spp. 21 (13%). The isolation rate of bacterial pathogens was high among patients with diabetic foot ulcers 83 (50.9%). Among bacterial isolates, 108 (66.2%) were observed as biofilm producers while 55 (33.8%) did not form biofilm in our model. The investigated biofilm producing bacterial isolates showed comparatively high resistance against tested antibiotics compared to non-biofilm producing bacterial isolates. The most effective antibiotics were amikacine and cefepime against all isolates. Increased multidrug resistance in biofilm producing bacteria associated with chronic wounds was observed in this study. Judicious use of antibiotics is needed to control the wound associated biofilm associated pathogens.

Differential Microbial Diversity in Drosophila melanogaster: Are Fruit Flies Potential Vectors of Opportunistic Pathogens?

PubMed Central

Maldonado-Morales, Génesis; Bayman, Paul

2017-01-01

Drosophila melanogaster has become a model system to study interactions between innate immunity and microbial pathogens, yet many aspects regarding its microbial community and interactions with pathogens remain unclear. In this study wild D. melanogaster were collected from tropical fruits in Puerto Rico to test how the microbiota is distributed and to compare the culturable diversity of fungi and bacteria. Additionally, we investigated whether flies are potential vectors of human and plant pathogens. Eighteen species of fungi and twelve species of bacteria were isolated from wild flies. The most abundant microorganisms identified were the yeast Candida inconspicua and the bacterium Klebsiella sp. The yeast Issatchenkia hanoiensis was significantly more common internally than externally in flies. Species richness was higher in fungi than in bacteria, but diversity was lower in fungi than in bacteria. The microbial composition of flies was similar internally and externally. We identified a variety of opportunistic human and plant pathogens in flies such as Alcaligenes faecalis, Aspergillus flavus, A. fumigatus, A. niger, Fusarium equiseti/oxysporum, Geotrichum candidum, Klebsiella oxytoca, Microbacterium oxydans, and Stenotrophomonas maltophilia. Despite its utility as a model system, D. melanogaster can be a vector of microorganisms that represent a potential risk to plant and public health. PMID:29234354

Radiation resistances and decontamination of common pathogenic bacteria contaminated in white scar oyster ( Crassostrea belcheri) in Thailand

NASA Astrophysics Data System (ADS)

Thupila, Nunticha; Ratana-arporn, Pattama; Wilaipun, Pongtep

2011-07-01

In Thailand, white scar oyster ( Crassostrea belcheri) was ranked for premium quality, being most expensive and of high demand. This oyster is often eaten raw, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. As limited alternative methods are available to sterilize the oyster while preserving the raw characteristic, irradiation may be considered as an effective method for decontamination. In this study, the radiation resistance of pathogenic bacteria commonly contaminating the oyster and the optimum irradiation doses for sterilization of the most radiation resistant bacteria were investigated. The radiation decimal reduction doses ( D10) of Salmonella Weltevreden DMST 33380, Vibrio parahaemolyticus ATCC 17802 and Vibrio vulnificus DMST 5852 were determined in broth culture and inoculated oyster homogenate. The D10 values of S. Weltevreden, V. parahaemolyticus and V. vulnificus in broth culture were 0.154, 0.132 and 0.059 kGy, while those of inoculated oyster homogenate were 0.330, 0.159 and 0.140 kGy, respectively. It was found that among the pathogens tested, S. Weltevreden was proved to be the most resistant species. An irradiation dose of 1.5 kGy reduced the counts of 10 5 CFU/g S. Weltevreden inoculated in oyster meat to an undetectable level. The present study indicated that a low-dose irradiation can improve the microbial quality of oyster and further reduce the risks from the food-borne pathogens without adversely affecting the sensory attributes.

Children with asthma by school age display aberrant immune responses to pathogenic airway bacteria as infants.

PubMed

Larsen, Jeppe Madura; Brix, Susanne; Thysen, Anna Hammerich; Birch, Sune; Rasmussen, Morten Arendt; Bisgaard, Hans

2014-04-01

Asthma is a highly prevalent chronic lung disease that commonly originates in early childhood. Colonization of neonatal airways with the pathogenic bacterial strains Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae is associated with increased risk of later childhood asthma. We hypothesized that children with asthma have an abnormal immune response to pathogenic bacteria in infancy. We aimed to assess the bacterial immune response in asymptomatic infants and the association with later development of asthma by age 7 years. The Copenhagen Prospective Studies on Asthma in Childhood birth cohort was followed prospectively, and asthma was diagnosed at age 7 years. The immune response to H influenzae, M catarrhalis, and S pneumoniae was analyzed in 292 infants using PBMCs isolated and stored since the age of 6 months. The immune response was assessed based on the pattern of cytokines produced and T-cell activation. The immune response to pathogenic bacteria was different in infants with asthma by 7 years of age (P = .0007). In particular, prospective asthmatic subjects had aberrant production of IL-5 (P = .008), IL-13 (P = .057), IL-17 (P = .001), and IL-10 (P = .028), whereas there were no differences in T-cell activation or peripheral T-cell composition. Children with asthma by school age exhibited an aberrant immune response to pathogenic bacteria in infancy. We propose that an abnormal immune response to pathogenic bacteria colonizing the airways in early life might lead to chronic airway inflammation and childhood asthma. Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Poly (Acetyl, Arginyl) Glucosamine as a Biofilm-reducing Water Line Treatment

USDA-ARS?s Scientific Manuscript database

Bacteria can attach and form biofilms on a surface hindering removal by common disinfectants. Some bacteria are better than others at forming this biofilm but once it is formed many pathogens can reside in the matrix. Salmonella spp. have been shown to have some biofilm forming capabilities but will...

Effect of sample preparation on the discrimination of bacterial isolates cultured in liquid nutrient media using laser induced breakdown spectroscopy

USDA-ARS?s Scientific Manuscript database

Laser induced breakdown spectroscopy (LIBS) is used as the basis for discrimination between 2 genera of gram-negative bacteria and 2 genera of gram-positive bacteria representing pathogenic threats commonly found in poultry processing rinse waters. Because LIBS-based discrimination relies primarily ...

Antimicrobial active herbal compounds against Acinetobacter baumannii and other pathogens.

PubMed

Tiwari, Vishvanath; Roy, Ranita; Tiwari, Monalisa

2015-01-01

Bacterial pathogens cause a number of lethal diseases. Opportunistic bacterial pathogens grouped into ESKAPE pathogens that are linked to the high degree of morbidity, mortality and increased costs as described by Infectious Disease Society of America. Acinetobacter baumannii is one of the ESKAPE pathogens which cause respiratory infection, pneumonia and urinary tract infections. The prevalence of this pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source and resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. The high level of acquired and intrinsic carbapenem resistance mechanisms acquired by these bacteria makes their eradication difficult. The pharmaceutical industry has no solution to this problem. Hence, it is an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In order to do this, here we have made an effort to review the active compounds of plants that have potent antibacterial activity against many bacteria including carbapenem resistant strain of A. baumannii. We have also briefly highlighted the separation and identification methods used for these active compounds. This review will help researchers involved in the screening of herbal active compounds that might act as a replacement for carbapenem.

Anaerobic Bacteria in Clinical Specimens – Frequent, But a Neglected Lot: A Five Year Experience at a Tertiary Care Hospital

PubMed Central

Shenoy, Padmaja Ananth; Gawda, Ashwini; Shetty, Seema; Anegundi, Renuka; Varma, Muralidhar; Mukhopadhyay, Chiranjay; Chawla, Kiran

2017-01-01

Introduction Anaerobic bacteria which constitute a significant proportion of the normal microbiota also cause variety of infections involving various anatomic sites. Considering the tedious culture techniques with longer turnaround time, anaerobic cultures are usually neglected by clinicians and microbiologists. Aim To study the frequency of isolation of different anaerobic bacteria from various clinical specimens. Materials and Methods A retrospective study to analyse the frequency of isolation of different anaerobic bacteria, was conducted over a period of five years from 2011 to 2015 including various clinical specimens submitted to anaerobic division of Microbiology laboratory. Anaerobic bacteria were isolated and identified following standard bacteriological techniques. Results Pathogenic anaerobes (n=336) were isolated from 278 (12.48%) of overall 2227 specimens processed with an average yield of 1.2 isolates. Anaerobes were isolated as polymicrobial flora with or without aerobic bacterial pathogens in 159 (57.2%) patients. Anaerobic Gram-negative bacilli (140, 41.7%) were the predominant isolates. B. fragilis group (67, 19.9%) were the most commonly isolated anaerobic pathogens. Anaerobes were predominantly isolated from deep seated abscess (23.9%). Conclusion Pathogenic anaerobes were isolated from various infection sites. Unless culture and susceptibility tests are performed as a routine, true magnitude of antimicrobial resistance among anaerobic pathogens will not be known. Knowledge of the distribution of these organisms may assist in the selection of appropriate empirical therapy for anaerobic infections. PMID:28892897

Vector-Borne Bacterial Plant Pathogens: Interactions with Hemipteran Insects and Plants

PubMed Central

Perilla-Henao, Laura M.; Casteel, Clare L.

2016-01-01

Hemipteran insects are devastating pests of crops due to their wide host range, rapid reproduction, and ability to transmit numerous plant-infecting pathogens as vectors. While the field of plant–virus–vector interactions has flourished in recent years, plant–bacteria–vector interactions remain poorly understood. Leafhoppers and psyllids are by far the most important vectors of bacterial pathogens, yet there are still significant gaps in our understanding of their feeding behavior, salivary secretions, and plant responses as compared to important viral vectors, such as whiteflies and aphids. Even with an incomplete understanding of plant–bacteria–vector interactions, some common themes have emerged: (1) all known vector-borne bacteria share the ability to propagate in the plant and insect host; (2) particular hemipteran families appear to be incapable of transmitting vector-borne bacteria; (3) all known vector-borne bacteria have highly reduced genomes and coding capacity, resulting in host-dependence; and (4) vector-borne bacteria encode proteins that are essential for colonization of specific hosts, though only a few types of proteins have been investigated. Here, we review the current knowledge on important vector-borne bacterial pathogens, including Xylella fastidiosa, Spiroplasma spp., Liberibacter spp., and ‘Candidatus Phytoplasma spp.’. We then highlight recent approaches used in the study of vector-borne bacteria. Finally, we discuss the application of this knowledge for control and future directions that will need to be addressed in the field of vector–plant–bacteria interactions. PMID:27555855

Transmission of the gut microbiota: spreading of health

PubMed Central

Browne, Hilary P.; Neville, B. Anne; Forster, Samuel C.; Lawley, Trevor D.

2018-01-01

Transmission of commensal intestinal bacteria between humans could promote health by establishing, maintaining and replenishing microbial diversity in the microbiota of an individual. Unlike pathogens, the routes of transmission for commensal bacteria remain unappreciated and poorly understood, despite the likely commonalities between both. Consequently, broad infection control measures that are designed to prevent pathogen transmission and infection, such as oversanitation and the overuse of antibiotics, may inadvertently affect human health by altering normal commensal transmission. In this Review, we discuss the mechanisms and factors that influence host-to-host transmission of the intestinal microbiota and examine how a better understanding of these processes will identify new approaches to nurture and restore transmission routes that are used by beneficial bacteria. PMID:28603278

Mechanisms of Toll-like receptor 4 endocytosis reveal a common immune-evasion strategy used by pathogenic and commensal bacteria

PubMed Central

Tan, Yunhao; Zanoni, Ivan; Cullen, Thomas W.; Goodman, Andrew L.; Kagan, Jonathan C.

2015-01-01

Microbe-induced receptor trafficking has emerged as an essential means to promote innate immune signal transduction. Upon detection of bacterial lipopolysaccharides (LPS), CD14 induces an inflammatory endocytosis pathway that delivers Toll-like Receptor 4 (TLR4) to endosomes. Although several regulators of CD14-dependent TLR4 endocytosis have been identified, the cargo selection mechanism during this process remains unknown. We reveal that, in contrast to classic cytosolic interactions that promoted the endocytosis of transmembrane receptors, TLR4 was selected as cargo for inflammatory endocytosis entirely through extracellular interactions. Mechanistically, the extracellular protein MD-2 bound to and dimerized TLR4 in order to promote this endocytic event. Our analysis of LPS variants from human pathogens and gut commensals revealed a common mechanism by which bacteria prevent inflammatory endocytosis. We suggest that evasion of CD14-dependent endocytosis is an attribute that transcends the concept of pathogenesis, and may be a fundamental feature of bacteria that inhabit eukaryotic hosts. PMID:26546281

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

PubMed

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

2013-07-01

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

Genome sequence of the thermotolerant foodborne pathogen Salmonella enterica serovar Senftenberg ATCC 43845 and phylogenetic analysis of Loci encoding increased protein quality control mechanisms

USDA-ARS?s Scientific Manuscript database

Salmonella enterica subsp. enterica bacteria are important foodborne pathogens with major economic impact. Some isolates exhibit increased heat tolerance, a concern for food safety. Analysis of a finished-quality genome sequence of an isolate commonly used in heat resistance studies, S. enterica sub...

Are seed and cone pathogens causing significant losses in Pacific Northwest seed orchards?

Treesearch

E.E. Nelson; W.G. Thies; C.Y. Li

1986-01-01

Cones systematically collected in 1983 from eight Douglas-fir seed orchards in western Washington and Oregon yielded large numbers of common molds. Fungi isolated from apparently healthy, developing cones were similar to those from necrotic cones. Necrosis in cones aborted in early stages of development was apparently not associated with pathogenic fungi or bacteria....

Electrochemical recognition and quantification of cytochrome c expression in Bacillus subtilis and aerobe/anaerobe Escherichia coli using N,N,N′,N′-tetramethyl-para-phenylene-diamine (TMPD)† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc03498a

PubMed Central

Kuss, S.; Tanner, E. E. L.; Ordovas-Montanes, M.

2017-01-01

The colorimetric identification of pathogenic and non-pathogenic bacteria in cell culture is commonly performed using the redox mediator N,N,N′,N′-tetramethyl-para-phenylene-diamine (TMPD) in the so-called oxidase test, which indicates the presence of bacterial cytochrome c oxidases. The presented study demonstrates the ability of electrochemistry to employ TMPD to detect bacteria and quantify the activity of bacterial cytochrome c oxidases. Cyclic voltammetry studies and chronoamperometry measurements performed on the model organism Bacillus subtilis result in a turnover number, calculated for single bacteria. Furthermore, trace amounts of cytochrome c oxidases were revealed in aerobically cultured Escherichia coli, which to our knowledge no other technique is currently able to quantify in molecular biology. The reported technique could be applied to a variety of pathogenic bacteria and has the potential to be employed in future biosensing technology. PMID:29568431

Significance of bacteria associated with invertebrates in drinking water distribution networks.

PubMed

Wolmarans, E; du Preez, H H; de Wet, C M E; Venter, S N

2005-01-01

The implication of invertebrates found in drinking water distribution networks to public health is of concern to water utilities. Previous studies have shown that the bacteria associated with the invertebrates could be potentially pathogenic to humans. This study investigated the level and identity of bacteria commonly associated with invertebrates collected from the drinking water treatment systems as well as from the main pipelines leaving the treatment works. On all sampling occasions bacteria were isolated from the invertebrate samples collected. The highest bacterial counts were observed for the samples taken before filtration as was expected. There were, however, indications that optimal removal of invertebrates from water did not always occur. During the investigation, 116 colonies were sampled for further identification. The isolates represent several bacterial genera and species that are pathogenic or opportunistic pathogens of humans. Diarrhoea, meningitis, septicaemia and skin infections are among the diseases associated with these organisms. The estimated number of bacteria that could be associated with a single invertebrate (as based on average invertebrate numbers) could range from 10 to 4000 bacteria per organism. It can, therefore, be concluded that bacteria associated with invertebrates might under the worst case scenario pose a potential health risk to water users. In the light of the above findings it is clear that invertebrates in drinking water should be controlled at levels as low as technically and economically feasible.

Detection and identification of intestinal pathogenic bacteria by hybridization to oligonucleotide microarrays

PubMed Central

Jin, Lian-Qun; Li, Jun-Wen; Wang, Sheng-Qi; Chao, Fu-Huan; Wang, Xin-Wei; Yuan, Zheng-Quan

2005-01-01

AIM: To detect the common intestinal pathogenic bacteria quickly and accurately. METHODS: A rapid (<3 h) experimental procedure was set up based upon the gene chip technology. Target genes were amplified and hybridized by oligonucleotide microarrays. RESULTS: One hundred and seventy strains of bacteria in pure culture belonging to 11 genera were successfully discriminated under comparatively same conditions, and a series of specific hybridization maps corresponding to each kind of bacteria were obtained. When this method was applied to 26 divided cultures, 25 (96.2%) were identified. CONCLUSION: Salmonella sp., Escherichia coli, Shigella sp., Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Proteus sp., Bacillus cereus, Vibrio cholerae, Enterococcus faecalis, Yersinia enterocolitica, and Campylobacter jejuni can be detected and identified by our microarrays. The accuracy, range, and discrimination power of this assay can be continually improved by adding further oligonucleotides to the arrays without any significant increase of complexity or cost. PMID:16437687

Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection

PubMed Central

Sistrunk, Jeticia R.; Nickerson, Kourtney P.; Chanin, Rachael B.; Rasko, David A.

2016-01-01

SUMMARY Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to this in vivo signal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens. PMID:27464994

Campylobacteriosis, Salmonellosis, Yersiniosis, and Listeriosis as Zoonotic Foodborne Diseases: A Review

PubMed Central

Chlebicz, Agnieszka; Śliżewska, Katarzyna

2018-01-01

Zoonoses are diseases transmitted from animals to humans, posing a great threat to the health and life of people all over the world. According to WHO estimations, 600 million cases of diseases caused by contaminated food were noted in 2010, including almost 350 million caused by pathogenic bacteria. Campylobacter, Salmonella, as well as Yersinia enterocolitica and Listeria monocytogenes may dwell in livestock (poultry, cattle, and swine) but are also found in wild animals, pets, fish, and rodents. Animals, often being asymptomatic carriers of pathogens, excrete them with faeces, thus delivering them to the environment. Therefore, pathogens may invade new individuals, as well as reside on vegetables and fruits. Pathogenic bacteria also penetrate food production areas and may remain there in the form of a biofilm covering the surfaces of machines and equipment. A common occurrence of microbes in food products, as well as their improper or careless processing, leads to common poisonings. Symptoms of foodborne infections may be mild, sometimes flu-like, but they also may be accompanied by severe complications, some even fatal. The aim of the paper is to summarize and provide information on campylobacteriosis, salmonellosis, yersiniosis, and listeriosis and the aetiological factors of those diseases, along with the general characteristics of pathogens, virulence factors, and reservoirs. PMID:29701663

Identification of Escherichia coli and Trueperella pyogenes isolated from the uterus of dairy cows using routine bacteriological testing and Fourier transform infrared spectroscopy.

PubMed

Jaureguiberry, María; Madoz, Laura Vanina; Giuliodori, Mauricio Javier; Wagener, Karen; Prunner, Isabella; Grunert, Tom; Ehling-Schulz, Monika; Drillich, Marc; de la Sota, Rodolfo Luzbel

2016-11-28

Uterine disorders are common postpartum diseases in dairy cows. In practice, uterine treatment is often based on systemic or locally applied antimicrobials with no previous identification of pathogens. Accurate on-farm diagnostics are not available, and routine testing is time-consuming and cost intensive. An accurate method that could simplify the identification of uterine pathogenic bacteria and improve pathogen-specific treatments could be an important advance to practitioners. The objective of the present study was to evaluate whether a database built with uterine bacteria from European dairy cows could be used to identify bacteria from Argentinean cows by Fourier transformed infrared (FTIR) spectroscopy. Uterine samples from 64 multiparous dairy cows with different types of vaginal discharge (VD) were collected between 5 and 60 days postpartum, analyzed by routine bacteriological testing methods and then re-evaluated by FTIR spectroscopy (n = 27). FTIR spectroscopy identified Escherichia coli in 12 out of 14 samples and Trueperella pyogenes in 8 out of 10 samples. The agreement between the two methods was good with a Kappa coefficient of 0.73. In addition, the likelihood for bacterial growth of common uterine pathogens such as E. coli and T. pyogenes tended to increase with VD score. The odds for a positive result to E. coli or T. pyogenes was 1.88 times higher in cows with fetid VD than in herdmates with clear normal VD. We conclude that the presence of E. coli and T. pyogenes in uterine samples from Argentinean dairy cows can be detected with FTIR with the use of a database built with uterine bacteria from European dairy cows. Future studies are needed to determine if FTIR can be used as an alternative to routine bacteriological testing methods.

Brucella melitensis and Mycobacterium tuberculosis depict overlapping gene expression patterns induced in infected THP-1 macrophages.

PubMed

Masoudian, M; Derakhshandeh, A; Ghahramani Seno, M M

2015-01-01

Pathogens infecting mammalian cells have developed various strategies to suppress and evade their hosts' defensive mechanisms. In this line, the intracellular bacteria that are able to survive and propagate within their host cells must have developed strategies to avert their host's killing attitude. Studying the interface of host-pathogen confrontation can provide valuable information for defining therapeutic approaches. Brucellosis, caused by the Brucella strains, is a zoonotic bacterial disease that affects thousands of humans and animals around the world inflicting discomfort and huge economic losses. Similar to many other intracellular dwelling bacteria, infections caused by Brucella are difficult to treat, and hence any attempt at identifying new and common therapeutic targets would prove beneficial for the purpose of curing infections caused by the intracellular bacteria. In THP-1 macrophage infected with Brucella melitensis we studied the expression levels of four host's genes, i.e. EMP2, ST8SIA4, HCP5 and FRMD5 known to be involved in pathogenesis of Mycobacterium tuberculosis. Our data showed that at this molecular level, except for FRMD5 that was downregulated, the other three genes were upregulated by B. melitensis. Brucella melitensis and M. tuberculosis go through similar intracellular processes and interestingly two of the investigated genes, i.e. EMP2 and ST4SIA8 were upregulated in THP-1 cell infected with B. melitensis similar to that reported for THP-1 cells infected with M. tuberculosis. At the host-pathogen interaction interface, this study depicts overlapping changes for different bacteria with common survival strategies; a fact that implies designing therapeutic approaches based on common targets may be possible.

Colonization of plants by human pathogenic bacteria in the course of organic vegetable production.

PubMed

Hofmann, Andreas; Fischer, Doreen; Hartmann, Anton; Schmid, Michael

2014-01-01

In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identify possible factors like bacterial species or serovariation, plant species or organic fertilizer types used, influencing the success of plant colonization by human pathogenic bacteria. Spinach and corn salad were chosen as model plants and were inoculated with different concentrations of Salmonella enterica sv. Weltevreden, Listeria monocytogenes sv. 4b and EGD-E sv. 1/2a either directly (axenic system) or via agricultural soil amended with spiked organic fertilizers (soil system). In addition to PCR- and culture-based detection methods, fluorescence in situ hybridization (FISH) was applied in order to localize bacteria on or in plant tissues. Our results demonstrate that shoots were colonized by the pathogenic bacteria at inoculation doses as low as 4 × 10 CFU/ml in the axenic system or 4 × 10(5) CFU/g in the soil system. In addition, plant species dependent effects were observed. Spinach was colonized more often and at lower inoculation doses compared to corn salad. Differential colonization sites on roots, depending on the plant species could be detected using FISH-CLSM analysis. Furthermore, the transfer of pathogenic bacteria to plants via organic fertilizers was observed more often and at lower initial inoculation doses when fertilization was performed with inoculated slurry compared to inoculated manure. Finally, it could be shown that by introducing a simple washing step, the bacterial contamination was reduced in most cases or even was removed completely in some cases.

Colonization of plants by human pathogenic bacteria in the course of organic vegetable production

PubMed Central

Hofmann, Andreas; Fischer, Doreen; Hartmann, Anton; Schmid, Michael

2014-01-01

In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identify possible factors like bacterial species or serovariation, plant species or organic fertilizer types used, influencing the success of plant colonization by human pathogenic bacteria. Spinach and corn salad were chosen as model plants and were inoculated with different concentrations of Salmonella enterica sv. Weltevreden, Listeria monocytogenes sv. 4b and EGD-E sv. 1/2a either directly (axenic system) or via agricultural soil amended with spiked organic fertilizers (soil system). In addition to PCR- and culture-based detection methods, fluorescence in situ hybridization (FISH) was applied in order to localize bacteria on or in plant tissues. Our results demonstrate that shoots were colonized by the pathogenic bacteria at inoculation doses as low as 4 × 10 CFU/ml in the axenic system or 4 × 105 CFU/g in the soil system. In addition, plant species dependent effects were observed. Spinach was colonized more often and at lower inoculation doses compared to corn salad. Differential colonization sites on roots, depending on the plant species could be detected using FISH-CLSM analysis. Furthermore, the transfer of pathogenic bacteria to plants via organic fertilizers was observed more often and at lower initial inoculation doses when fertilization was performed with inoculated slurry compared to inoculated manure. Finally, it could be shown that by introducing a simple washing step, the bacterial contamination was reduced in most cases or even was removed completely in some cases. PMID:24829562

Effects of tillage and poultry manure application rates on Salmonella and fecal indicator bacteria concentrations in tiles draining Des Moines Lobe soils

USDA-ARS?s Scientific Manuscript database

Application of poultry manure (PM) to cropland as fertilizer is a common practice in artificially drained regions of the Upper Midwest. To assess the potential for PM to contribute pathogenic bacteria to downstream waters, information is needed on the impacts of manure management and tillage practi...

Study of the microbial ecology of wild and aquacultured Tunisian fresh fish.

PubMed

Boulares, Mouna; Mejri, Lobna; Hassouna, Mnasser

2011-10-01

Eighty samples of fresh fish were collected in Tunisia and analyzed for microbial load. Quality and hygienic safety of the meat and intestines of wild and aquacultured fresh fish were determined. The mesophilic aerobic plate count and populations of psychrotrophic lactic acid bacteria (LAB) and other psychrotrophic bacteria ranged from 5.67 to 7.29, 4.51 to 6, and 5.07 to 6.21 log CFU/g, respectively. For all microbiological determinations, bacterial counts were lower in meat than in the intestines of fresh fish. For all samples lower microbial populations were found in most of the wild fish than in the aquacultured fish. No isolates of the pathogenic genera Salmonella and Listeria were detected in any sample. Among the 160 strains of biopreservative psychrotrophic LAB and the 150 strains of spoilage psychrotrophic gram-negative bacteria identified by biochemical and molecular methods, Lactobacillus (six species) and Pseudomonas (six species) predominated. Lactococcus, Leuconostoc, Carnobacterium (C. piscicola and C. divergens), Aeromonas, and Photobacterium were the most common genera, and Lactococcus lactis, Lactobacillus plantarum, Pseudomonas fluorescens, and Aeromonas hydrophila were the most common species. These findings indicate that the microbiological quality of fresh fish in Tunisia can be preserved by controlling pathogenic and psychrotrophic bacteria.

Rice Bran Amendment Suppresses Potato Common Scab by Increasing Antagonistic Bacterial Community Levels in the Rhizosphere.

PubMed

Tomihama, Tsuyoshi; Nishi, Yatsuka; Mori, Kiyofumi; Shirao, Tsukasa; Iida, Toshiya; Uzuhashi, Shihomi; Ohkuma, Moriya; Ikeda, Seishi

2016-07-01

Potato common scab (PCS), caused by pathogenic Streptomyces spp., is a serious disease in potato production worldwide. Cultural practices, such as optimizing the soil pH and irrigation, are recommended but it is often difficult to establish stable disease reductions using these methods. Traditionally, local farmers in southwest Japan have amended soils with rice bran (RB) to suppress PCS. However, the scientific mechanism underlying disease suppression by RB has not been elucidated. The present study showed that RB amendment reduced PCS by repressing the pathogenic Streptomyces population in young tubers. Amplicon sequencing analyses of 16S ribosomal RNA genes from the rhizosphere microbiome revealed that RB amendment dramatically changed bacterial composition and led to an increase in the relative abundance of gram-positive bacteria such as Streptomyces spp., and this was negatively correlated with PCS disease severity. Most actinomycete isolates derived from the RB-amended soil showed antagonistic activity against pathogenic Streptomyces scabiei and S. turgidiscabies on R2A medium. Some of the Streptomyces isolates suppressed PCS when they were inoculated onto potato plants in a field experiment. These results suggest that RB amendment increases the levels of antagonistic bacteria against PCS pathogens in the potato rhizosphere.

Elucidation of Bacterial Pneumonia-Causing Pathogens in Patients with Respiratory Viral Infection

PubMed Central

Jung, Hwa Sik; Kang, Byung Ju; Ra, Seung Won; Seo, Kwang Won; Jegal, Yangjin; Jun, Jae-Bum; Jung, Jiwon; Jeong, Joseph; Jeon, Hee-Jeong; Ahn, Jae-Sung

2017-01-01

Background Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Methods Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. Results A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. Conclusion The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia. PMID:28905531

Altered virulence potential of Salmonella Enteritidis cultured in different foods: A cumulative effect of differential gene expression and immunomodulation.

PubMed

Jaiswal, Sangeeta; Sahoo, Prakash Kumar; Ryan, Daniel; Das, Jugal Kishore; Chakraborty, Eesha; Mohakud, Nirmal Kumar; Suar, Mrutyunjay

2016-08-02

Salmonella enterica serovars Enteritidis (S. Enteritidis) is one of the most common causes of food borne illness. Bacterial growth environment plays an important role in regulating gene expression thereby affecting the virulence profile of the bacteria. Different foods present diverse growth conditions which may affect the pathogenic potential of the bacteria. In the present study, the effect of food environments on the pathogenic potential of S. Enteritidis has been evaluated. S. Enteritidis was grown in different foods e.g. egg white, peanut butter and milk, and virulent phenotypes were compared to those grown in Luria Bertani broth. In-vivo experiments in C57BL/6 mice revealed S. Enteritidis grown in egg white did not induce significant (p<0.001) production of proinflammatory cytokines in mice and were unable to cause colitis despite efficient colonization in cecum, mesenteric lymph node, spleen and liver. Further studies revealed that bacteria grown in LB activated MAP Kinase and NFκB pathways efficiently, while those grown in egg white poorly activated the above pathways which can account for the decreased production of proinflammatory cytokines. qRT PCR analysis revealed SPI-1 effectors were downregulated in bacteria grown in egg white. Interestingly, bacteria grown in egg white showed reversal of phenotype upon change in growth media to LB. Additionally, bacteria grown in milk and peanut butter showed different degrees of virulence in mice as compared to those grown in LB media. Thus, the present study demonstrates that, S. Enteritidis grown in egg white colonizes systemic sites without causing colitis in a mouse model, while bacteria grown in milk and peanut butter show different pathogenicity profiles suggesting that food environments significantly affect the pathogenicity of S. Enteritidis. Copyright © 2016 Elsevier B.V. All rights reserved.

In vitro growth characteristics of five candidate aquaculture probiotics and two fish pathogens grown in fish intestinal mucus.

PubMed

Vine, Niall G; Leukes, Winston D; Kaiser, Horst

2004-02-09

The selection of probiotics for aquaculture is usually based on their antagonism towards pathogens. However, other criteria such as growth, attachment to intestinal mucus and production of beneficial compounds should also be considered. We suggest a protocol for the isolation and selection of potential probiotic bacteria based on their in vitro growth characteristics and propose a ranking index (RI) to screen potential aquaculture probionts. We suggest that the lag period and doubling time are the most important criteria for the comparison of growth curves, hence the RI is based on the doubling time (t(d)) and lag period (lambda) obtained from the growth profile of each bacterium. Bacteria were isolated from the gut of the common clownfish, Amphiprion percula, and screened for antagonistic activity towards seven aquatic pathogens. All five candidate probiotics showed antagonism to various aquatic pathogens. When grown in intestinal fish mucus no probiotic had a RI higher than the two tested pathogens (Aeromonas hydrophila and Vibrio alginolyticus). However, candidate probiont AP1 had a faster specific growth rate (micro) (0.05) than the pathogens (0.049 and 0.047 respectively), while AP5 grown in marine broth had a shorter lag period than the pathogens. Strategies to increase probiotic concentration include the inoculation of high concentrations and the preconditioning of these bacteria to reduce the lag period. It should be tested whether or not such strategies will allow the probiotic bacteria to dominate initially and thereby gain a competitive advantage. This could become an important aspect under in vivo conditions where both attachment and nutrient supply differ from that found in in vitro studies.

Urinary tract infection: recent insight into the evolutionary arms race between uropathogenic Escherichia coli and our immune system.

PubMed

Schwab, Sebastian; Jobin, Katarzyna; Kurts, Christian

2017-12-01

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide. Humans evolved various immune-dependent and independent defense mechanisms, while pathogens evolved multiple virulence factors to fight back. This article summarizes recent findings regarding the arms race between hosts and pathogens in UTIs. It was recently reported that macrophage subsets regulate neutrophil-mediated defense in primary UTIs but seem to subvert adaptive immunity upon re-infection. Moreover, some bacterial strains can survive inside macrophages, leading to recurrent infections. Inflammasome activation results in infected host cell death and pathogen release, facilitating the removal of intracellular bacteria. As a counteraction, some bacteria evolved mechanisms to disrupt inflammasome activation. Mucosal-associated invariant T cells are further effectors that can lyse infected epithelial cells and release intracellular bacteria. Once released, the bacteria are phagocytosed by neutrophils. However, some bacteria can inhibit neutrophil migration and deprive neutrophils of nutrients. Furthermore, the complement system, considered generally bactericidal, is exploited by the bacteria for cellular invasion. Another weapon against UTI is antimicrobial peptides, e.g. ribonuclease 7, but its production is inhibited by certain bacterial strains. Thus the arms race in UTI is ongoing, and knowing the enemy's methods can help in developing new drugs to win the race. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Recovery Estimation of Dried Foodborne Pathogens Is Directly Related to Rehydration Kinetics

PubMed Central

Lang, Emilie; Zoz, Fiona; Iaconelli, Cyril; Guyot, Stéphane; Alvarez-Martin, Pablo; Beney, Laurent; Perrier-Cornet, Jean-Marie; Gervais, Patrick

2016-01-01

Drying is a common process which is used to preserve food products and technological microorganisms, but which is deleterious for the cells. The aim of this study is to differentiate the effects of drying alone from the effects of the successive and necessary rehydration. Rehydration of dried bacteria is a critical step already studied in starter culture but not for different kinetics and not for pathogens. In the present study, the influence of rehydration kinetics was investigated for three foodborne pathogens involved in neonatal diseases caused by the consumption of rehydrated milk powder: Salmonella enterica subsp. enterica serovar Typhimurium, Salmonella enterica subsp. enterica serovar Senftenberg and Cronobacter sakazakii. Bacteria were dried in controlled relative humidity atmospheres and then rehydrated using different methods. Our results showed that the survival of the three pathogens was strongly related to rehydration kinetics. Consequently, rehydration is an important step to consider during food safety assessment or during studies of dried foodborne pathogens. Also, it has to be considered with more attention in consumers’ homes during the preparation of food, like powdered infant formula, to avoid pathogens recovery. PMID:27494169

The Interplay between Entamoeba and Enteropathogenic Bacteria Modulates Epithelial Cell Damage

PubMed Central

Galván-Moroyoqui, José Manuel; Domínguez-Robles, M. del Carmen; Franco, Elizabeth; Meza, Isaura

2008-01-01

Background Mixed intestinal infections with Entamoeba histolytica, Entamoeba dispar and bacteria with exacerbated manifestations of disease are common in regions where amoebiasis is endemic. However, amoeba–bacteria interactions remain largely unexamined. Methodology Trophozoites of E. histolytica and E. dispar were co-cultured with enteropathogenic bacteria strains Escherichia coli (EPEC), Shigella dysenteriae and a commensal Escherichia coli. Amoebae that phagocytosed bacteria were tested for a cytopathic effect on epithelial cell monolayers. Cysteine proteinase activity, adhesion and cell surface concentration of Gal/GalNAc lectin were analyzed in amoebae showing increased virulence. Structural and functional changes and induction of IL-8 expression were determined in epithelial cells before and after exposure to bacteria. Chemotaxis of amoebae and neutrophils to human IL-8 and conditioned culture media from epithelial cells exposed to bacteria was quantified. Principal Findings E. histolytica digested phagocytosed bacteria, although S. dysenteriae retained 70% viability after ingestion. Phagocytosis of pathogenic bacteria augmented the cytopathic effect of E. histolytica and increased expression of Gal/GalNAc lectin on the amoebic surface and increased cysteine proteinase activity. E. dispar remained avirulent. Adhesion of amoebae and damage to cells exposed to bacteria were increased. Additional increases were observed if amoebae had phagocytosed bacteria. Co-culture of epithelial cells with enteropathogenic bacteria disrupted monolayer permeability and induced expression of IL-8. Media from these co-cultures and human recombinant IL-8 were similarly chemotactic for neutrophils and E. histolytica. Conclusions Epithelial monolayers exposed to enteropathogenic bacteria become more susceptible to E. histolytica damage. At the same time, phagocytosis of pathogenic bacteria by amoebae further increased epithelial cell damage. Significance The in vitro system presented here provides evidence that the Entamoeba/enteropathogenic bacteria interplay modulates epithelial cell responses to the pathogens. In mixed intestinal infections, where such interactions are possible, they could influence the outcome of disease. The results offer insights to continue research on this phenomenon. PMID:18648517

Pathogenic bacteria carried by companion animals and their susceptibility to antibacterial agents.

PubMed

Buma, Ryoko; Maeda, Takuya; Kamei, Masaharu; Kourai, Hiroki

2006-03-01

Results of the investigation showed that there was a difference in the bacteria isolated from dogs, cats and their living environment. The number and species isolated from the hair and front paw samples from dogs kept outdoors and from cats were greater and more varied than those from the samples from dogs kept indoors. Staphylococcus, Micrococcus and Bacillus were frequently detected from skin surfaces. On the other hand, Escherichia, Pseudomonas, Proteus and others were detected on each sampling area on dogs kept outdoors and on cats. About 60% of the bacteria commonly causes infectious diseases and carries a risk of food poisoning. Moreover, Pasteurella multocida, which causes pasteurellasis, a kind of zoonosis, was isolated from dogs and cats. These pathogenic bacteria were transmitted from animals to humans by direct contact. This result suggests that direct contact with dogs and cats and contact with aerosols can possibly transmit infectious diseases. Most of the isolates (75.9%, 60/79) were resistant to antibacterial agents. We then investigated the effect of household detergents and pet care deodorant sprays containing antibacterial agents on isolates from dogs and cats. They were effective in preventing the transmission of pathogens from dogs and cats to humans.

[The method and result analyses of pathogenic bacteria culture on chronic periprosthetic joint infection after total knee arthroplasty and total hip arthroplasty].

PubMed

Ji, Baochao; Xu, Enjie; Cao, Li; Yang, Desheng; Xu, Boyong; Guo, Wentao; Aili, Rehei

2015-02-01

To analyze the results of pathogenic bacteria culture on chronic periprosthetic joint infection after total knee arthroplasty (TKA) and total hip arthroplasty (THA). The medical data of 23 patients with chronic periprosthetic joint infection after TKA or THA from September 2010 to March 2014 were reviewed. Fifteen cases of TKA and 8 cases of THA were included in this study. There were 12 male and 11 female patients with the mean age of 62 years (range from 32 to 79 years), and among them 9 patients with sinus. All patients discontinued antibiotic therapy for a minimum of 2 weeks before arthrocentesis, taking pathogenic bacteria culture and antimicrobial susceptibility test by using synovial fluid taken preoperatively and intraoperatively of revision. Common pathogenic bacteria culture and pathological biopsy were taken on tissues intraoperatively of revision. Culture-negative specimens were prolonged the period of incubation for 2 weeks. The overall culture-positive rate of all 23 patients for 1 week before revision was 30.4% (7/23), and the positive rate of culture-negative samples which prolonged for 2 weeks was 39.1% (9/23). The overall culture-positive rate of patients for 1 week intraoperatively of revision was 60.9% (14/23), and the positive rate of culture-negative samples which prolonged for 2 weeks was 82.6% (19/23). The incubation results of 7 cases (30.4%) preoperatively conformed to that of intraoperation. The culture-positive rate of pathogenic bacteria culture can be increased evidently by discontinuing antimicrobial therapy for a minimum of 2 weeks prior to the definite diagnosis.

Causative Pathogens of Febrile Neutropaenia in Children Treated for Acute Lymphoblastic Leukaemia.

PubMed

Lam, Joyce Cm; Chai, Jie Yang; Wong, Yi Ling; Tan, Natalie Wh; Ha, Christina Tt; Chan, Mei Yoke; Tan, Ah Moy

2015-11-01

Treatment of acute lymphoblastic leukaemia (ALL) using intensive chemotherapy has resulted in high cure rates but also substantial morbidity. Infective complications represent a significant proportion of treatment-related toxicity. The objective of this study was to describe the microbiological aetiology and clinical outcome of episodes of chemotherapy-induced febrile neutropaenia in a cohort of children treated for ALL at our institution. Patients with ALL were treated with either the HKSGALL93 or the Malaysia-Singapore (Ma-Spore) 2003 chemotherapy protocols. The records of 197 patients who completed the intensive phase of treatment, defined as the period of treatment from induction, central nervous system (CNS)-directed therapy to reinduction from June 2000 to January 2010 were retrospectively reviewed. There were a total of 587 episodes of febrile neutropaenia in 197 patients, translating to an overall rate of 2.98 episodes per patient. A causative pathogen was isolated in 22.7% of episodes. An equal proportion of Gram-positive bacteria (36.4%) and Gram-negative bacteria (36.4%) were most frequently isolated followed by viral pathogens (17.4%), fungal pathogens (8.4%) and other bacteria (1.2%). Fungal organisms accounted for a higher proportion of clinically severe episodes of febrile neutropaenia requiring admission to the high-dependency or intensive care unit (23.1%). The overall mortality rate from all episodes was 1.5%. Febrile neutropaenia continues to be of concern in ALL patients undergoing intensive chemotherapy. The majority of episodes will not have an identifiable causative organism. Gram-positive bacteria and Gram-negative bacteria were the most common causative pathogens identified. With appropriate antimicrobial therapy and supportive management, the overall risk of mortality from febrile neutropaenia is extremely low.

RETRACTED ARTICLE: Quorum-sensing of bacteria and its application

NASA Astrophysics Data System (ADS)

Jiang, Guoliang; Su, Mingxia

2009-12-01

Quorum sensing, or auto induction, as a cell density dependent signaling mechanism in many microorganisms, is triggered via auto inducers which passively diffuse across the bacterial envelope and therefore intracellulaly accumulate only at higher bacterial densities to regulate specialized processes such as genetic competence, bioluminescence, virulence and sporulation. N-acyl homoserine lactones are the most common type of signal molecules. Aquaculture is one of the fastest-growing food-producing industries, but disease outbreaks caused by pathogenic bacteria are a significant constraint on the development of the sector worldwide. Many of these pathogens have been found to be controlled by their quorum sensing systems. As there is relevance between the pathogenic bacteria's virulence factor expression and their auto inducers, quorum quenching is a new effective anti-infective strategy to control infections caused by bacterial pathogens in aquaculture. The techniques used to do this mainly include the following: (1) the inhibition of signal molecule biosynthesis, (2) blocking signal transduction, and (3) chemical inactivation and biodegradation of signal molecules. To provide a basis for finding alternative means of controlling aquatic diseases by quorum quenching instead of treatment by antibiotics and disinfectants, we will discuss the examination, purification and identification of auto inducers in this paper.

Development of a single-tube loop-mediated isothermal amplification assay for detection of four pathogens of bacterial meningitis.

PubMed

Huy, Nguyen Tien; Hang, Le Thi Thuy; Boamah, Daniel; Lan, Nguyen Thi Phuong; Van Thanh, Phan; Watanabe, Kiwao; Huong, Vu Thi Thu; Kikuchi, Mihoko; Ariyoshi, Koya; Morita, Kouichi; Hirayama, Kenji

2012-12-01

Several loop-mediated isothermal amplification (LAMP) assays have been developed to detect common causative pathogens of bacterial meningitis (BM). However, no LAMP assay is reported to detect Streptococcus agalactiae and Streptococcus suis, which are also among common pathogens of BM. Moreover, it is laborious and expensive by performing multiple reactions for each sample to detect bacterial pathogen. Thus, we aimed to design and develop a single-tube LAMP assay capable of detecting multiple bacterial species, based on the nucleotide sequences of the 16S rRNA genes of the bacteria. The nucleotide sequences of the 16S rRNA genes of main pathogens involved in BM were aligned to identify conserved regions, which were further used to design broad range specific LAMP assay primers. We successfully designed a set of broad range specific LAMP assay primers for simultaneous detection of four species including Staphylococcus aureus, Streptococcus pneumoniae, S. suis and S. agalactiae. The broad range LAMP assay was highly specific without cross-reactivity with other bacteria including Haemophilus influenzae, Neisseria meningitidis and Escherichia coli. The sensitivity of our LAMP assay was 100-1000 times higher compared with the conventional PCR assay. The bacterial species could be identified after digestion of the LAMP products with restriction endonuclease DdeI and HaeIII. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Antimicrobial susceptibility of foodborne pathogens in organic or natural production systems: an overview.

PubMed

Jacob, Megan E; Fox, James Trent; Reinstein, Shelby L; Nagaraja, T G

2008-12-01

Organic and natural food production systems are increasing in popularity, at least partially because consumers perceive that these niche markets provide healthier and safer food products. One major difference between these niche markets and conventional production systems is the use of antimicrobials. Because antimicrobial agents exert selective pressures for antimicrobial resistance, relating antimicrobial susceptibility of foodborne bacteria to niche market production systems is of interest. Other differences between production systems might also influence the susceptibility of foodborne pathogens. The objective of this review is to compare the impact of food animal production systems on the antimicrobial susceptibility of common foodborne bacterial pathogens. Studies comparing the susceptibility of such pathogens were diverse in terms of geographic location, procedures, species of bacteria, and antimicrobials evaluated; thus, it was difficult to draw conclusions. The literature is highly variable in terms of production type and practices and susceptibility associations, although few studies have compared truly organic and conventional practices. When statistical associations were found between production type and minimum inhibitory concentrations or percentage of isolates resistant for a particular pathogen, the isolates from conventionally reared animals/products were more commonly resistant than the comparison group (organic, antibiotic free, etc.). Therefore, further studies are needed to better assess public health consequences of antimicrobial resistance and food animal production systems, specifically organic or natural versus conventional.

Bacterial genome engineering and synthetic biology: combating pathogens.

PubMed

Krishnamurthy, Malathy; Moore, Richard T; Rajamani, Sathish; Panchal, Rekha G

2016-11-04

The emergence and prevalence of multidrug resistant (MDR) pathogenic bacteria poses a serious threat to human and animal health globally. Nosocomial infections and common ailments such as pneumonia, wound, urinary tract, and bloodstream infections are becoming more challenging to treat due to the rapid spread of MDR pathogenic bacteria. According to recent reports by the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC), there is an unprecedented increase in the occurrence of MDR infections worldwide. The rise in these infections has generated an economic strain worldwide, prompting the WHO to endorse a global action plan to improve awareness and understanding of antimicrobial resistance. This health crisis necessitates an immediate action to target the underlying mechanisms of drug resistance in bacteria. The advent of new bacterial genome engineering and synthetic biology (SB) tools is providing promising diagnostic and treatment plans to monitor and treat widespread recalcitrant bacterial infections. Key advances in genetic engineering approaches can successfully aid in targeting and editing pathogenic bacterial genomes for understanding and mitigating drug resistance mechanisms. In this review, we discuss the application of specific genome engineering and SB methods such as recombineering, clustered regularly interspaced short palindromic repeats (CRISPR), and bacterial cell-cell signaling mechanisms for pathogen targeting. The utility of these tools in developing antibacterial strategies such as novel antibiotic production, phage therapy, diagnostics and vaccine production to name a few, are also highlighted. The prevalent use of antibiotics and the spread of MDR bacteria raise the prospect of a post-antibiotic era, which underscores the need for developing novel therapeutics to target MDR pathogens. The development of enabling SB technologies offers promising solutions to deliver safe and effective antibacterial therapies.

Elucidation of Bacterial Pneumonia-Causing Pathogens in Patients with Respiratory Viral Infection.

PubMed

Jung, Hwa Sik; Kang, Byung Ju; Ra, Seung Won; Seo, Kwang Won; Jegal, Yangjin; Jun, Jae Bum; Jung, Jiwon; Jeong, Joseph; Jeon, Hee Jeong; Ahn, Jae Sung; Lee, Taehoon; Ahn, Jong Joon

2017-10-01

Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia. Copyright©2017. The Korean Academy of Tuberculosis and Respiratory Diseases

An Introduction to the Avian Gut Microbiota and the Effects of Yeast-Based Prebiotic-Type Compounds as Potential Feed Additives

PubMed Central

Roto, Stephanie M.; Rubinelli, Peter M.; Ricke, Steven C.

2015-01-01

The poultry industry has been searching for a replacement for antibiotic growth promoters in poultry feed as public concerns over the use of antibiotics and the appearance of antibiotic resistance has become more intense. An ideal replacement would be feed amendments that could eliminate pathogens and disease while retaining economic value via improvements on body weight and feed conversion ratios. Establishing a healthy gut microbiota can have a positive impact on growth and development of both body weight and the immune system of poultry while reducing pathogen invasion and disease. The addition of prebiotics to poultry feed represents one such recognized way to establish a healthy gut microbiota. Prebiotics are feed additives, mainly in the form of specific types of carbohydrates that are indigestible to the host while serving as substrates to select beneficial bacteria and altering the gut microbiota. Beneficial bacteria in the ceca easily ferment commonly studied prebiotics, producing short-chain fatty acids, while pathogenic bacteria and the host are unable to digest their molecular bonds. Prebiotic-like substances are less commonly studied, but show promise in their effects on the prevention of pathogen colonization, improvements on the immune system, and host growth. Inclusion of yeast and yeast derivatives as probiotic and prebiotic-like substances, respectively, in animal feed has demonstrated positive associations with growth performance and modification of gut morphology. This review will aim to link together how such prebiotics and prebiotic-like substances function to influence the native and beneficial microorganisms that result in a diverse and well-developed gut microbiota. PMID:26664957

Characterization and pathogenicity assessment of gut-associated microbes of muga silkworm Antheraea assamensis Helfer (Lepidoptera: Saturniidae).

PubMed

Haloi, Kishor; Kalita, Moni Kankana; Nath, Ramesh; Devi, Dipali

2016-07-01

Antheraea assamensis Helfer (muga silkworm) is an economically important endemic insect species of North Eastern Region of India. The silkworm is often susceptible to infection by pathogenic bacteria, leads to a disease commonly known as flacherie which causes 40% loss per annum to the silk industry. In this study, we have reported isolation, characterization and pathogenicity assessment of gut-associated bacteria of healthy and diseased muga silkworms. Thirty five bacterial isolates were screened from the gut of healthy and diseased silkworms by morphological observation and biochemical tests. 11 and 5 strains from healthy and diseased silkworm respectively were identified by 16S rRNA gene sequencing and analyzed. Pseudomonas aeruginosa (DRK1), Ornithinibacillus bavariensis (DRK2), Achromobacter xylosoxidans (KH3) and Staphylococcus aureus (FLG1) strains were commonly found in healthy as well as diseased larvae whereas, Bacillus thuringiensis (MK1) was found only in diseased larvae. Survivability analysis was performed with the identified strains by injection and oral administration (10(4)CFU/ml). The immune response of the silkworm against the pathogen was also studied by phenoloxidase and lysozyme enzyme activity assay, total and differential hemocyte count and phagocytic activity of hemocytes. It was observed that S. aureus, P. aeruginosa and B. thuringiensis significantly reduced the survivability of silkworm (p<0.001) hence found highly pathogenic. The lethal concentrations (LC50) values of the pathogenic strains were calculated at different time intervals (24, 48, 72 and 96h) within the range from 1.38×10(2) to 3.63×10(7)CFU/ml. The pathogenic groups demonstrated inhibition of phenoloxidase activity and decreased in total hemocyte count after 48h of infection. However, the lysozyme activity increased significantly in the pathogenic groups compared to the control (p<0.05). Granulocytes and plasmatocytes showed phagocytosis whereas; other types of cells did not show any phagocytic activity. Increasing granulocytes and plasmatocytes counts corroborates the results of phagocytic activity. The present study might be helpful in understanding the disease prognosis and colonization of bacteria causing the disease in muga silkworm. Copyright © 2016 Elsevier Inc. All rights reserved.

Gardnerella vaginalis and anaerobic bacteria in genital disease.

PubMed Central

Tabaqchali, S; Wilks, M; Thin, R N

1983-01-01

In a study of Gardnerella vaginalis and anaerobic bacteria in non-specific vaginitis (NSV) and other genital disease 89 patients attending a genital medicine clinic had vaginal samples examined for conventional pathogens and for quantitative analysis of G vaginalis and aerobic and anaerobic bacterial flora. The overall incidence of G vaginalis was 20%; G vaginalis (mean concentration 7.0 log10/g of secretion) occurred predominantly in patients with NSV (57%) but also in sexual contacts of non-specific urethritis (NSU) (37.5%) and in patients with other conditions (11.8%). G vaginalis is therefore a relatively common isolate in patients with vaginal discharge. The concentration of aerobic and anaerobic bacteria ranged from 4.9-11.0 log10/g of secretion with an anaerobe-to-aerobe ratio of 10:1. Anaerobic bacteria, particularly anaerobic Gram-positive cocci (mean concentrations 7.7 log10/g), were present in patients with NSV and in association with G vaginalis, but they also occurred in other clinical groups and with other pathogens, particularly Trichomonas vaginalis. Anaerobic bacteria may therefore play an important role in the pathogenesis of vaginal infections. PMID:6600955

Photodynamic antimicrobial chemotherapy using zinc phthalocyanine derivative for bacterial skin infection

NASA Astrophysics Data System (ADS)

Chen, Zhuo; Zhang, Yaxin; Li, Linsen; Zhou, Shanyong; Chen, Jincan; Hu, Ping; Huang, Mingdong

2014-09-01

Folliculitis, furunculosis and acne vulgaris are very common skin disorders of the hair follicles and are associated with large grease-producing (sebaceous) glands. Although the detailed mechanisms involved these skin disorders are not fully understood, it is believed that the bacteria Propionibacterium acnes and Staphylococcus aureus are the key pathogenic factors involved. Conventional treatments targeting the pathogenic factors include a variety of topical and oral medications such as antibiotics. The wide use of antibiotics leads to bacterial resistance, and hence there is a need for new alternatives in above bacterial skin treatment. Photodynamic antimicrobial chemotherapy (PACT) is based on an initial photosensitization of the infected area, followed by irradiation with visible light, producing singlet oxygen which is cytotoxic to bacteria. Herein we reported a zinc phthalocyanine derivative, pentalysine β-carbonylphthalocyanine zinc (ZnPc-(Lys)5) and its PACT effect for the bacteria involved in these skin infections. Our results demonstrated strong bactericidal effects of this photosensitizer on both strains of the bacteria, suggesting ZnPc-(Lys)5 as a promising antimicrobial photosensitizer for the treatment of infectious diseases caused by these bacteria.

Study on antibacterial effect of medlar and hawthorn compound extract in vitro.

PubMed

Niu, Yang; Nan, Yi; Yuan, Ling; Wang, Rong

2013-01-01

This paper evaluated the antibacterial effect of medlar and hawthorn compound extract in vitro. Water extract method and ethanol extraction method was adopted to prepare the compound extracts, and disc diffusion method and improved test tube doubling dilution method were used to conduct the antibacterial test on the two common pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumonia, in vitro. The results showed that medlar and hawthorn compound extract was moderately sensitive to Staphylococcus aureus, while its inhibiting effect on Klebsiella pneumoniae was particularly significant, moreover, the antibacterial effect of ethanol extract was better than water extract. Medlar and hawthorn compounds had good antibacterial effect on the two pathogenic bacteria.

Comparative Bacterial Proteomics: Analysis of the Core Genome Concept

PubMed Central

Callister, Stephen J.; McCue, Lee Ann; Turse, Joshua E.; Monroe, Matthew E.; Auberry, Kenneth J.; Smith, Richard D.; Adkins, Joshua N.; Lipton, Mary S.

2008-01-01

While comparative bacterial genomic studies commonly predict a set of genes indicative of common ancestry, experimental validation of the existence of this core genome requires extensive measurement and is typically not undertaken. Enabled by an extensive proteome database developed over six years, we have experimentally verified the expression of proteins predicted from genomic ortholog comparisons among 17 environmental and pathogenic bacteria. More exclusive relationships were observed among the expressed protein content of phenotypically related bacteria, which is indicative of the specific lifestyles associated with these organisms. Although genomic studies can establish relative orthologous relationships among a set of bacteria and propose a set of ancestral genes, our proteomics study establishes expressed lifestyle differences among conserved genes and proposes a set of expressed ancestral traits. PMID:18253490

[Molecular characterization of pathogenic bacteria of the respiratory tract in peruvian patients with cystic fibrosis].

PubMed

Aquino, Ruth; Gonzáles, Emely; Samaniego, Sol; Rivera, Juan; Cedeño, Virna; Urbina, Yrene; Diringer, Benoit

2017-01-01

To molecularly characterize the pathogenic bacteria of the respiratory tract isolated from patients with cystic fibrosis (CF) in Peru. Bacterial communities cultured from sputum samples of pediatric and adult patients with CF admitted to the Edgardo Rebagliati Martins National Hospital and the National Institute of Child Health were characterized. Standard microbiological techniques were used for bacterial culture, and gene sequencing of 16S rRNA and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and tandem MALDI-TOF mass spectrometry (MALDI TOF/TOF) were used for molecular characterization. Seventeen bacterial strains were characterized by 16S rRNA sequencing, and the identified pathogenic bacteria were Pseudomonas aeruginosa (31.5%), Staphylococcus aureus (12.6%), Pseudomonas spp. (11.8%), and Klebsiella oxytoca (3.1%). MALDI-TOF analysis generated a series of spectra representative of each isolated bacterial species, whereas MALDI TOF/TOF analysis identified the peptides and proteins of the most common strains and provided data on pathogenicity and sensitivity to antibiotics. The primary pathogenic microorganisms found in the respiratory tract of patients with CF in Peru were the same as those found in other countries. This study is the first to perform 16S rRNA sequencing as well as MALDI-TOF and MALDI-TOF/TOF analysis of the bacterial pathogens circulating in Peru. The inclusion of proteomic analysis further allowed for the identification of native microorganisms involved in CF.

The Arabidopsis leaf transcriptome reveals distinct but also overlapping responses to colonization by phyllosphere commensals and pathogen infection with impact on plant health.

PubMed

Vogel, Christine; Bodenhausen, Natacha; Gruissem, Wilhelm; Vorholt, Julia A

2016-10-01

Plants are colonized by a variety of bacteria, most of which are not pathogenic. Currently, the plant responses to phyllosphere commensals or to pathogen infection in the presence of commensals are not well understood. Here, we examined the transcriptional response of Arabidopsis thaliana leaves to colonization by common commensal bacteria in a gnotobiotic system using RNA sequencing and conducted plant mutant assays. Arabidopsis responded differently to the model bacteria Sphingomonas melonis Fr1 (S.Fr1) and Methylobacterium extorquens PA1 (M.PA1). Whereas M.PA1 only marginally affected the expression of plant genes (< 10), S.Fr1 colonization changed the expression of almost 400 genes. For the latter, genes related to defense responses were activated and partly overlapped with those elicited by the pathogen Pseudomonas syringae DC3000 (Pst). As S.Fr1 is able to mediate plant protective activity against Pst, we tested plant immunity mutants and found that the pattern-recognition co-receptor mutant bak1/bkk1 showed attenuated S.Fr1-dependent plant protection. The experiments demonstrate that the plant responds differently to members of its natural phyllosphere microbiota. A subset of commensals trigger expression of defense-related genes and thereby may contribute to plant health upon pathogen encounter. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Label and label-free based surface-enhanced Raman scattering for pathogen bacteria detection: A review.

PubMed

Liu, Yu; Zhou, Haibo; Hu, Ziwei; Yu, Guangxia; Yang, Danting; Zhao, Jinshun

2017-08-15

Rapid, accurate detection of pathogen bacteria is a highly topical research area for the sake of food safety and public health. Surface-enhanced Raman scattering (SERS) is being considered as a powerful and attractive technique for pathogen bacteria detection, due to its sensitivity, high speed, comparatively low cost, multiplexing ability and portability. This contribution aims to give a comprehensive overview of SERS as a technique for rapid detection of pathogen bacteria based on label and label-free strategies. A brief tutorial on SERS is given first of all. Then we summarize the recent trends and developments of label and label-free based SERS applied to detection of pathogen bacteria, including the relatively complete interpretation of SERS spectra. In addition, multifunctional SERS platforms for pathogen bacteria in matrix are discussed as well. Furthermore, an outlook of the work done and a perspective on the future directions of SERS as a reliable tool for real-time pathogen bacteria detection are given. Copyright © 2017 Elsevier B.V. All rights reserved.

Benefits of a European project on diagnostics of highly pathogenic agents and assessment of potential "dual use" issues.

PubMed

Grunow, Roland; Ippolito, G; Jacob, D; Sauer, U; Rohleder, A; Di Caro, A; Iacovino, R

2014-01-01

Quality assurance exercises and networking on the detection of highly infectious pathogens (QUANDHIP) is a joint action initiative set up in 2011 that has successfully unified the primary objectives of the European Network on Highly Pathogenic Bacteria (ENHPB) and of P4-laboratories (ENP4-Lab) both of which aimed to improve the efficiency, effectiveness, and response capabilities of laboratories directed at protecting the health of European citizens against high consequence bacteria and viruses of significant public health concern. Both networks have established a common collaborative consortium of 37 nationally and internationally recognized institutions with laboratory facilities from 22 European countries. The specific objectives and achievements include the initiation and establishment of a recognized and acceptable quality assurance scheme, including practical external quality assurance exercises, comprising living agents, that aims to improve laboratory performance, accuracy, and detection capabilities in support of patient management and public health responses; recognized training schemes for diagnostics and handling of highly pathogenic agents; international repositories comprising highly pathogenic bacteria and viruses for the development of standardized reference material; a standardized and transparent Biosafety and Biosecurity strategy protecting healthcare personnel and the community in dealing with high consequence pathogens; the design and organization of response capabilities dealing with cross-border events with highly infectious pathogens including the consideration of diagnostic capabilities of individual European laboratories. The project tackled several sensitive issues regarding Biosafety, Biosecurity and "dual use" concerns. The article will give an overview of the project outcomes and discuss the assessment of potential "dual use" issues.

Benefits of a European Project on Diagnostics of Highly Pathogenic Agents and Assessment of Potential “Dual Use” Issues

PubMed Central

Grunow, Roland; Ippolito, G.; Jacob, D.; Sauer, U.; Rohleder, A.; Di Caro, A.; Iacovino, R.

2014-01-01

Quality assurance exercises and networking on the detection of highly infectious pathogens (QUANDHIP) is a joint action initiative set up in 2011 that has successfully unified the primary objectives of the European Network on Highly Pathogenic Bacteria (ENHPB) and of P4-laboratories (ENP4-Lab) both of which aimed to improve the efficiency, effectiveness, and response capabilities of laboratories directed at protecting the health of European citizens against high consequence bacteria and viruses of significant public health concern. Both networks have established a common collaborative consortium of 37 nationally and internationally recognized institutions with laboratory facilities from 22 European countries. The specific objectives and achievements include the initiation and establishment of a recognized and acceptable quality assurance scheme, including practical external quality assurance exercises, comprising living agents, that aims to improve laboratory performance, accuracy, and detection capabilities in support of patient management and public health responses; recognized training schemes for diagnostics and handling of highly pathogenic agents; international repositories comprising highly pathogenic bacteria and viruses for the development of standardized reference material; a standardized and transparent Biosafety and Biosecurity strategy protecting healthcare personnel and the community in dealing with high consequence pathogens; the design and organization of response capabilities dealing with cross-border events with highly infectious pathogens including the consideration of diagnostic capabilities of individual European laboratories. The project tackled several sensitive issues regarding Biosafety, Biosecurity and “dual use” concerns. The article will give an overview of the project outcomes and discuss the assessment of potential “dual use” issues. PMID:25426479

Recent development of mass spectrometry and proteomics applications in identification and typing of bacteria

PubMed Central

Chui, Huixia; Domish, Larissa; Hernandez, Drexler; Wang, Gehua

2016-01-01

Identification and typing of bacteria occupy a large fraction of time and work in clinical microbiology laboratories. With the certification of some MS platforms in recent years, more applications and tests of MS‐based diagnosis methods for bacteria identification and typing have been created, not only on well‐accepted MALDI‐TOF‐MS‐based fingerprint matches, but also on solving the insufficiencies of MALDI‐TOF‐MS‐based platforms and advancing the technology to areas such as targeted MS identification and typing of bacteria, bacterial toxin identification, antibiotics susceptibility/resistance tests, and MS‐based diagnostic method development on unique bacteria such as Clostridium and Mycobacteria. This review summarizes the recent development in MS platforms and applications in bacteria identification and typing of common pathogenic bacteria. PMID:26751976

Characterization, Microbial Community Structure, and Pathogen Occurrence in Urban Faucet Biofilms in South China

PubMed Central

Lin, Huirong; Zhang, Shuting; Gong, Song; Zhang, Shenghua; Yu, Xin

2015-01-01

The composition and microbial community structure of the drinking water system biofilms were investigated using microstructure analysis and 454 pyrosequencing technique in Xiamen city, southeast of China. SEM (scanning electron microscope) results showed different features of biofilm morphology in different fields of PVC pipe. Extracellular matrix material and sparse populations of bacteria (mainly rod-shaped and coccoid) were observed. CLSM (confocal laser scanning microscope) revealed different distributions of attached cells, extracellular proteins, α-polysaccharides, and β-polysaccharides. The biofilms had complex bacterial compositions. Differences in bacteria diversity and composition from different tap materials and ages were observed. Proteobacteria was the common and predominant group in all biofilms samples. Some potential pathogens (Legionellales, Enterobacteriales, Chromatiales, and Pseudomonadales) and corrosive microorganisms were also found in the biofilms. This study provides the information of characterization and visualization of the drinking water biofilms matrix, as well as the microbial community structure and opportunistic pathogens occurrence. PMID:26273617

Uterine diseases in cattle after parturition

PubMed Central

Sheldon, I. Martin; Williams, Erin J.; Miller, Aleisha N.A.; Nash, Deborah M.; Herath, Shan

2008-01-01

Bacterial contamination of the uterine lumen is common in cattle after parturition, often leading to infection and uterine disease. Clinical disease can be diagnosed and scored by examination of the vaginal mucus, which reflects the presence of pathogenic bacteria such as Escherichia coli and Arcanobacterium pyogenes. Viruses may also cause uterine disease and bovine herpesvirus 4 (BoHV-4) is tropic for endometrial cells, causing a rapid cytopathic effect. The elimination of pathogens by the innate immune system is dependent on pattern recognition receptors binding pathogen-associated molecules. Uterine epithelial and stromal cells express receptors such as Toll-like Receptor 4 that binds E. coli lipopolysaccharide. The infertility associated with uterine disease is caused by damage to the endometrium and disruption of ovarian cyclic activity. Bacteria modulate endometrial prostaglandin secretion, and perturb ovarian follicle growth and function. Understanding the molecular basis of uterine disease will lead to novel approaches to treating infertility. PMID:18329302

Risk factors for community-acquired bacterial meningitis.

PubMed

Lundbo, Lene Fogt; Benfield, Thomas

2017-06-01

Bacterial meningitis is a significant burden of disease and mortality in all age groups worldwide despite the development of effective conjugated vaccines. The pathogenesis of bacterial meningitis is based on complex and incompletely understood host-pathogen interactions. Some of these are pathogen-specific, while some are shared between different bacteria. We searched the database PubMed to identify host risk factors for bacterial meningitis caused by the pathogens Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b, because they are three most common causative bacteria beyond the neonatal period. We describe a number of risk factors; including socioeconomic factors, age, genetic variation of the host and underlying medical conditions associated with increased susceptibility to invasive bacterial infections in both children and adults. As conjugated vaccines are available for these infections, it is of utmost importance to identify high risk patients to be able to prevent invasive disease.

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

PubMed Central

Beceiro, Alejandro; Tomás, María

2013-01-01

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

Enteric bacteria boost defences against oxidative stress in Entamoeba histolytica.

PubMed

Varet, Hugo; Shaulov, Yana; Sismeiro, Odile; Trebicz-Geffen, Meirav; Legendre, Rachel; Coppée, Jean-Yves; Ankri, Serge; Guillen, Nancy

2018-06-13

Oxidative stress is one of the strongest toxic factors in nature: it can harm or even kill cells. Cellular means of subverting the toxicity of oxidative stress are important for the success of infectious diseases. Many types of bacterium inhabit the intestine, where they can encounter pathogens. During oxidative stress, we analyzed the interplay between an intestinal parasite (the pathogenic amoeba Entamoeba histolytica - the agent of amoebiasis) and enteric bacteria (microbiome residents, pathogens and probiotics). We found that live enteric bacteria protected E. histolytica against oxidative stress. By high-throughput RNA sequencing, two amoebic regulatory modes were observed with enteric bacteria but not with probiotics. The first controls essential elements of homeostasis, and the second the levels of factors required for amoeba survival. Characteristic genes of both modes have been acquired by the amoebic genome through lateral transfer from the bacterial kingdom (e.g. glycolytic enzymes and leucine-rich proteins). Members of the leucine-rich are homologous to proteins from anti-bacterial innate immune such as Toll-like receptors. The factors identified here suggest that despite its old age in evolutionary terms, the protozoan E. histolytica displays key characteristics of higher eukaryotes' innate immune systems indicating that components of innate immunity existed in the common ancestor of plants and animals.

Prunus mume extract exhibits antimicrobial activity against pathogenic oral bacteria.

PubMed

Seneviratne, Chamida J; Wong, Ricky W K; Hägg, Urban; Chen, Yong; Herath, Thanuja D K; Samaranayake, P Lakshman; Kao, Richard

2011-07-01

Prunus mume is a common fruit in Asia, which has been used in traditional Chinese medicine. In this study, we focused on the antimicrobial properties of Prunus mume extract against oral pathogens related to dental caries and periodontal diseases. A total of 15 oral pathogens including Streptococcus mutans, S. sobrinus, S. mitis, S. sanguinis, Lactobacillus acidophilus, P. gingivalis, Aggregatibacter actinomycetemcomitans, and Candida species were included in the study. Initially, agar diffusion assay was performed to screen the antimicrobial activities of Prunus mume extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were then determined for sensitive species. Effect of Prunus mume extract on human oral keratinocytes (HOK) viability was also tested. In the agar diffusion assay, drug suspension of 2 g/mL was able to inhibit all the bacterial species tested, but not the fungal species. MIC and MBC range of Prunus mume extract against the oral bacteria was 0.15625-0.0003 g/mL and P. gingivalis being the most susceptible species. Prune extract did not cause any detrimental effect on HOK. Prunus mume extract may be a potential candidate for developing an oral antimicrobial agent to control or prevent dental diseases associated with oral pathogenic bacteria. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

Decontamination Efficacy of Ultraviolet Radiation against Biofilms of Common Nosocomial Bacteria.

PubMed

Tingpej, Pholawat; Tiengtip, Rattana; Kondo, Sumalee

2015-06-01

Ultraviolet radiation (UV) is commonly used to destroy microorganisms in the health-care environment. However, the efficacy of UV radiation against bacteria growing within biofilms has never been studied. To measure the sterilization effectiveness of UV radiation against common healthcare associated pathogens growing within biofilms. Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Streptococcus epidermidis, Escherichia coli, ESBL-producing E. coli, Pseudomonas aeruginosa and Acinetobacter baumannii were cultivated in the Calgary Biofilm Device. Their biofilms were placed 50 cm from the UV lamp within the Biosafety Cabinet. Viability test, crystal violet assay and a scanning electron microscope were used to evaluate the germicidal efficacy. Within 5 minutes, UV radiation could kill S. aureus, MRSA, S. epidermidis, A. baumannii and ESBL-producing E. coli completely while it required 20 minutes and 30 minutes respectively to kill E. coli and P. aeruginosa. However, the amounts of biomass and the ultrastructure between UV-exposed biofilms and controls were not significantly different. UV radiation is effective in inactivating nosocomial pathogens grown within biofilms, but not removing biofilms and EPS. The biofilm of P. aeruginosa was the most durable.

A Helicobacter pylori Homolog of Eukaryotic Flotillin Is Involved in Cholesterol Accumulation, Epithelial Cell Responses and Host Colonization.

PubMed

Hutton, Melanie L; D'Costa, Kimberley; Rossiter, Amanda E; Wang, Lin; Turner, Lorinda; Steer, David L; Masters, Seth L; Croker, Ben A; Kaparakis-Liaskos, Maria; Ferrero, Richard L

2017-01-01

The human pathogen Helicobacter pylori acquires cholesterol from membrane raft domains in eukaryotic cells, commonly known as "lipid rafts." Incorporation of this cholesterol into the H. pylori cell membrane allows the bacterium to avoid clearance by the host immune system and to resist the effects of antibiotics and antimicrobial peptides. The presence of cholesterol in H. pylori bacteria suggested that this pathogen may have cholesterol-enriched domains within its membrane. Consistent with this suggestion, we identified a hypothetical H. pylori protein (HP0248) with homology to the flotillin proteins normally found in the cholesterol-enriched domains of eukaryotic cells. As shown for eukaryotic flotillin proteins, HP0248 was detected in detergent-resistant membrane fractions of H. pylori . Importantly, H. pylori HP0248 mutants contained lower levels of cholesterol than wild-type bacteria ( P < 0.01). HP0248 mutant bacteria also exhibited defects in type IV secretion functions, as indicated by reduced IL-8 responses and CagA translocation in epithelial cells ( P < 0.05), and were less able to establish a chronic infection in mice than wild-type bacteria ( P < 0.05). Thus, we have identified an H. pylori flotillin protein and shown its importance for bacterial virulence. Taken together, the data demonstrate important roles for H. pylori flotillin in host-pathogen interactions. We propose that H. pylori flotillin may be required for the organization of virulence proteins into membrane raft-like structures in this pathogen.

Hostile takeover: Manipulation of HIF-1 signaling in pathogen-associated cancers (Review).

PubMed

Zhu, Caixia; Zhu, Qing; Wang, Chong; Zhang, Liming; Wei, Fang; Cai, Qiliang

2016-10-01

Hypoxia-inducible factor (HIF)-1 is a central regulator in the adaptation process of cell response to hypoxia (low oxygen). Emerging evidence has demonstrated that HIF-1 plays an important role in the development and progression of many types of human diseases, including pathogen-associated cancers. In the present review, we summarize the recent understandings of how human pathogenic agents including viruses, bacteria and parasites deregulate cellular HIF-1 signaling pathway in their associated cancer cells, and highlight the common molecular mechanisms of HIF-1 signaling activated by these pathogenic infection, which could act as potential diagnostic markers and new therapeutic strategies against human infectious cancers.

List of New Names of Plant Pathogenic Bacteria (2008-2010)

USDA-ARS?s Scientific Manuscript database

In 2010 the International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria published the Comprehensive List of Names of Plant Pathogenic Bacteria, 1980-2007 to provide an authoritative register of names of plant pathogens. In this manuscript we up-date the list of na...

Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review.

PubMed

Alegbeleye, Oluwadara Oluwaseun; Singleton, Ian; Sant'Ana, Anderson S

2018-08-01

Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts. The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety. This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest. Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms. Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biofilms on Hospital Shower Hoses: Characterization and Implications for Nosocomial Infections

EPA Science Inventory

Although the source of drinking water used in hospitals is commonly, biofilms on water pipelines are refuge to bacteria that survive different disinfection strategies. Drinking water (DW) biofilms are well known to harbor opportunistic pathogens, however, these biofilm communitie...

Identification and antimicrobial resistance of pathogens in neonatal septicemia in China-A meta-analysis.

PubMed

Li, Jing-Yang; Chen, Shang-Qin; Yan, Yan-Yan; Hu, Ying-Ying; Wei, Jia; Wu, Qiu-Ping; Lin, Zhen-Lang; Lin, Jing

2018-06-01

The purpose of this study was to analyze the distribution and antimicrobial resistance of common bacterial pathogens causing neonatal septicemia based on a systematic review of published studies in China. Articles on neonatal sepsis published in the Chinese literature from 2009 to 2014 were identified according to the inclusion and exclusion criteria. Data were extracted and analyzed using Comprehensive Meta-Analysis software. A total of 71 studies were included, in which a total of 8080 bacterial species were isolated from culture-positive blood samples. The pooled distribution rates of common bacterial pathogens were as follows: Staphylococcus 67.1% (95% confidence interval (CI) 63.3-70.6%), Enterococcus 4.1% (95% CI 3.5-4.8%), Streptococcus 2.3% (95% CI 1.6-3.2%), Escherichia coli 7.4% (95% CI 6.4-8.7%), Klebsiella 6.5% (95% CI 5.2-8.2%), Enterobacterium 2.3% (95% CI 1.9-2.8%), Acinetobacter 1.6% (95% CI 1.3-2.0%), Pseudomonas 1.7% (95% CI 1.3-2.2%). Among the Staphylococcus aureus strains isolated, more than 60% were methicillin-resistant (MRSA). In addition, over 50% of the Gram-negative isolates, including Escherichia and Klebsiella, were resistant to the commonly used third-generation cephalosporins. Most of the Gram-positive and Gram-negative bacteria isolated were sensitive to aminoglycosides, especially amikacin. It is concluded that Staphylococcus, especially coagulase-negative Staphylococcus, continues to be the principal organism responsible for neonatal septicemia in China; Enterobacteriaceae are common among the Gram-negative isolates. Significant numbers of MRSA and multidrug-resistant Gram-negative bacteria are being isolated as pathogens responsible for neonatal septicemia in China. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Antibacterial isoeugenol coating on stainless steel and polyethylene surfaces prevents biofilm growth.

PubMed

Nielsen, C K; Subbiahdoss, G; Zeng, G; Salmi, Z; Kjems, J; Mygind, T; Snabe, T; Meyer, R L

2018-01-01

Pathogenic bacteria can spread between individuals or between food items via the surfaces they share. Limiting the survival of pathogens on surfaces, therefore, presents an opportunity to limit at least one route of how pathogens spread. In this study, we propose that a simple coating with the essential oil isoeugenol can be used to circumvent the problem of bacterial transfer via surfaces. Two commonly used materials, stainless steel and polyethylene, were coated by physical adsorption, and the coatings were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurements. We quantified and visualized the colonization of coated and uncoated surfaces by three bacteria: Staphylococcus aureus, Listeria monocytogenes and Pseudomonas fluorescens. No viable cells were detected on surfaces coated with isoeugenol. The isoeugenol coating prepared with simple adsorption proved effective in preventing biofilm formation on stainless steel and polyethylene surfaces. The result was caused by the antibacterial effect of isoeugenol, as the coating did not diminish the adhesive properties of the surface. Our study demonstrates that a simple isoeugenol coating can prevent biofilm formation of S. aureus, L. monocytogenes and P. fluorescens on two commonly used surfaces. © 2017 The Society for Applied Microbiology.

Ozone disinfection of home nebulizers effectively kills common cystic fibrosis bacterial pathogens.

PubMed

Towle, Dana; Baker, Vanisha; Schramm, Craig; O'Brien, Matthew; Collins, Melanie S; Feinn, Richard; Murray, Thomas S

2018-05-01

The Cystic Fibrosis Foundation (CFF) recommends routine nebulizer disinfection for patients but compliance is challenging due to the heavy burden of home care. SoClean® is a user friendly ozone based home disinfection device currently for home respiratory equipment. The objective of this study was to determine whether SoClean® has potential as a disinfection device for families with CF by killing CF associated bacteria without altering nebulizer output. Ozone based disinfection effectively kills bacterial pathogens inoculated to home nebulizer equipment without gross changes in nebulizer function. Common bacterial pathogens associated with CF were inoculated onto the PariLC® jet nebulizer and bacterial recovery compared with or without varied ozone exposure. In separate experiments, nebulizer output was estimated after repeated ozone exposure by weighing the nebulizer. Ozone disinfection was time dependent with a 5 min infusion time and 120 min dwell time effectively killing >99.99% bacteria tested including Pseudomonas aeruginosa and Staphylococcus aureus. Over 250 h of repeat ozone exposure did not alter nebulizer output. This suggests SoClean® has potential as a user-friendly disinfection technique for home respiratory equipment. © 2018 Wiley Periodicals, Inc.

Comprehensive bactericidal activity of an ethanol-based hand gel in 15 seconds.

PubMed

Kampf, Günter; Hollingsworth, Angela

2008-01-22

Some studies indicate that the commonly recommended 30 s application time for the post contamination treatment of hands may not be necessary as the same effect may be achieved with some formulations in a shorter application time such as 15 s. We evaluated the bactericidal activity of an ethanol-based hand gel (Sterillium Comfort Gel) within 15 s in a time-kill-test against 11 Gram-positive, 16 Gram-negative bacteria and 11 emerging bacterial pathogens. Each strain was evaluated in quadruplicate. The hand gel (85% ethanol, w/w) was found to reduce all 11 Gram-positive and all 16 Gram-negative bacteria by more than 5 log10 steps within 15 s, not only against the ATCC test strains but also against corresponding clinical isolates. In addition, a log10 reduction > 5 was observed against all tested emerging bacterial pathogens. The ethanol-based hand gel was found to have a broad spectrum of bactericidal activity in only 15 s which includes the most common species causing nosocomial infections and the relevant emerging pathogens. Future research will hopefully help to find out if a shorter application time for the post contamination treatment of hands provides more benefits or more risks.

A survey of the indigenous microbiota (bacteria) in three species of mussels from the Clinch and Holston Rivers, Virginia

USGS Publications Warehouse

Starliper, Clifford E.; Neves, Richard J.; Hanlon, Shane D.; Whittington, Pamela

2008-01-01

Freshwater mussel conservation efforts by many federal and state agencies have increased in recent years. This has led to a greater number of stream surveys, in which mussel die-offs involving high numbers of dead and moribund animals are being observed and reported with greater frequency. Typically, die-offs have been incidentally observed while research was being done for other purposes, therefore, accurate mortality data have been difficult to obtain. Specifically, seasonal die-offs were noted in localized areas of the Clinch and Holston Rivers, Virginia, and to lesser degrees, in neighboring rivers in this geographic region, including southeast Virginia. The observed mussel species affected were primarily the slabside pearlymussel (Lexingtonia dolabelloides) and to lesser extents, the pheasantshell (Actinonaias pectorosa), rainbow mussel (Villosa iris), and the endangered shiny pigtoe (Fusconaia cor). To determine if a bacterial pathogen might be involved in these recurring mussel die-offs, this study examined characteristics of the indigenous microbiota (bacteria) from healthy mussels from sites on the Clinch and Holston Rivers where die-offs were previously observed. These baseline data will allow for recognition of bacterial pathogens in future mussel die-offs. Means for total bacteria from soft tissues ranged from 1.77 × 105 to 3.55 × 106 cfu/g; whereas, the range in means from fluids was 2.92 × 104 to 8.60 × 105 cfu/mL. A diverse microbiota were recovered, including species that are common in freshwater aquatic environments. The most common bacterial groups recovered were motile Aeromonas spp. and nonfermenting bacteria. Flavobacterium columnare, a pathogen to cool- and warm-water fishes was recovered from one specimen, a Villosa iris from the Clinch River.

Case-control study of pneumonia patients with Streptococcus anginosus group bacteria in their sputum.

PubMed

Hirai, Jun; Sakanashi, Daisuke; Haranaga, Shusaku; Kinjo, Takeshi; Hagihara, Mao; Kato, Hideo; Suematsu, Hiroyuki; Yamagishi, Yuka; Fujita, Jiro; Mikamo, Hiroshige

2016-12-01

In recent years, Streptococcus anginosus group (SAG) bacteria are becoming increasingly recognized as important pneumonia-causing pathogens. Although several small studies have been reported, the features of SAG pneumonia remain unclear, because the identification of SAG from sputum cultures is not routinely performed in most microbiology laboratories. The aim of this study was to elucidate the clinical characteristics of SAG pneumonia. This was a retrospective case-control study utilizing data obtained in our hospital between September 2009 and June 2016. We investigated 31 patients with SAG pneumonia (PWP), and also assessed the difference between the 31 PWP and 37 patients without pneumonia (PWOP) in whose sputum SAG was detected. Seventy-one percent of the patients were men and the median age was 78 years in the PWP. Univariate analysis indicated that the PWP were significantly more often a bed-ridden (p < 0.01) with comorbid aspiration than were the PWOP (p < 0.05). Among the PWP, nursing and healthcare-associated pneumonia (NHCAP) was the more common type of pneumonia (54.8%). S. anginosus was detected significantly more frequently in sputum cultures of PWP than PWOP (p < 0.01), and multiple pathogens were detected more frequently in PWP (p < 0.01). Streptococcus constellatus was the most frequently detected pathogen in patients with a single bacterial infection. Empyema was observed only in patients with multiple bacteria. SAG should be recognized as important causative pathogens of pneumonia, particularly among elderly patients with underlying disease associated with aspiration. NHCAP was the more common type of SAG pneumonia in this study. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Antibiotic and synergistic effect of Leu-Lys rich peptide against antibiotic resistant microorganisms isolated from patients with cholelithiasis.

PubMed

Jeong, Nari; Kim, Jin-Young; Park, Seong-Cheol; Lee, Jong-Kook; Gopal, Ramamourthy; Yoo, Suyeon; Son, Byoung Kwan; Hahm, Joon Soo; Park, Yoonkyung; Hahm, Kyung-Soo

2010-09-03

Pseudomonas aeruginosa has eventually developed resistance against flomoxef sodium, isepamicin and cefpiramide. Therefore, in this study, the antibacterial activity and synergistic effects of the amphipathic-derived P5-18mer antimicrobial peptide were tested against pathogens associated with cholelithiasis that have developed resistance against commonly used antibiotics. The results were then compared with the activities of the amphipathic-derived peptide, P5-18mer, melittin and common antibiotics. Growth inhibition of planktonic bacteria was tested using the National Committee for Clinical Laboratory Standards (NCCLS). The bactericidal activity of the antimicrobial peptides was measured using time-kill curves. Synergistic effects were evaluated by testing the effects of P5-18mer alone and in combination with flomoxef sodium, isepamicin or cefpiramide at 0.5xMIC. P5-18mer peptide displayed strong activity against pathogens and flomoxef sodium, isepamicin and cefpiramide-resistant bacteria cell lines obtained from a patient with gallstones; however, it did not exert cytotoxicity against the human keratinocyte HaCat cell line. In addition, the results of time-kill curves indicated that P5-18mer peptide exerted bactericidal activity against four strains of P. aeruginosa. Finally, the use of P5-18mer and antibiotics exerted synergistic effects against cell lines that were resistant to commonly used antibiotics. These results indicate that this class of peptides has a rapid microbicidal effect on flomoxef sodium, isepamicin and cefpiramide-resistant strains of P. aeruginosa. Therefore, these peptides may be used as a lead drug for the treatment of acquired pathogens from patients with cholelithiasis who are affected with antibiotic-resistant bacteria. Copyright 2010 Elsevier Inc. All rights reserved.

Prediction of molecular mimicry candidates in human pathogenic bacteria.

PubMed

Doxey, Andrew C; McConkey, Brendan J

2013-08-15

Molecular mimicry of host proteins is a common strategy adopted by bacterial pathogens to interfere with and exploit host processes. Despite the availability of pathogen genomes, few studies have attempted to predict virulence-associated mimicry relationships directly from genomic sequences. Here, we analyzed the proteomes of 62 pathogenic and 66 non-pathogenic bacterial species, and screened for the top pathogen-specific or pathogen-enriched sequence similarities to human proteins. The screen identified approximately 100 potential mimicry relationships including well-characterized examples among the top-scoring hits (e.g., RalF, internalin, yopH, and others), with about 1/3 of predicted relationships supported by existing literature. Examination of homology to virulence factors, statistically enriched functions, and comparison with literature indicated that the detected mimics target key host structures (e.g., extracellular matrix, ECM) and pathways (e.g., cell adhesion, lipid metabolism, and immune signaling). The top-scoring and most widespread mimicry pattern detected among pathogens consisted of elevated sequence similarities to ECM proteins including collagens and leucine-rich repeat proteins. Unexpectedly, analysis of the pathogen counterparts of these proteins revealed that they have evolved independently in different species of bacterial pathogens from separate repeat amplifications. Thus, our analysis provides evidence for two classes of mimics: complex proteins such as enzymes that have been acquired by eukaryote-to-pathogen horizontal transfer, and simpler repeat proteins that have independently evolved to mimic the host ECM. Ultimately, computational detection of pathogen-specific and pathogen-enriched similarities to host proteins provides insights into potentially novel mimicry-mediated virulence mechanisms of pathogenic bacteria.

Prediction of molecular mimicry candidates in human pathogenic bacteria

PubMed Central

Doxey, Andrew C; McConkey, Brendan J

2013-01-01

Molecular mimicry of host proteins is a common strategy adopted by bacterial pathogens to interfere with and exploit host processes. Despite the availability of pathogen genomes, few studies have attempted to predict virulence-associated mimicry relationships directly from genomic sequences. Here, we analyzed the proteomes of 62 pathogenic and 66 non-pathogenic bacterial species, and screened for the top pathogen-specific or pathogen-enriched sequence similarities to human proteins. The screen identified approximately 100 potential mimicry relationships including well-characterized examples among the top-scoring hits (e.g., RalF, internalin, yopH, and others), with about 1/3 of predicted relationships supported by existing literature. Examination of homology to virulence factors, statistically enriched functions, and comparison with literature indicated that the detected mimics target key host structures (e.g., extracellular matrix, ECM) and pathways (e.g., cell adhesion, lipid metabolism, and immune signaling). The top-scoring and most widespread mimicry pattern detected among pathogens consisted of elevated sequence similarities to ECM proteins including collagens and leucine-rich repeat proteins. Unexpectedly, analysis of the pathogen counterparts of these proteins revealed that they have evolved independently in different species of bacterial pathogens from separate repeat amplifications. Thus, our analysis provides evidence for two classes of mimics: complex proteins such as enzymes that have been acquired by eukaryote-to-pathogen horizontal transfer, and simpler repeat proteins that have independently evolved to mimic the host ECM. Ultimately, computational detection of pathogen-specific and pathogen-enriched similarities to host proteins provides insights into potentially novel mimicry-mediated virulence mechanisms of pathogenic bacteria. PMID:23715053

Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses

PubMed Central

2011-01-01

Background Black elderberries (Sambucus nigra L.) are well known as supportive agents against common cold and influenza. It is further known that bacterial super-infection during an influenza virus (IV) infection can lead to severe pneumonia. We have analyzed a standardized elderberry extract (Rubini, BerryPharma AG) for its antimicrobial and antiviral activity using the microtitre broth micro-dilution assay against three Gram-positive bacteria and one Gram-negative bacteria responsible for infections of the upper respiratory tract, as well as cell culture experiments for two different strains of influenza virus. Methods The antimicrobial activity of the elderberry extract was determined by bacterial growth experiments in liquid cultures using the extract at concentrations of 5%, 10%, 15% and 20%. The inhibitory effects were determined by plating the bacteria on agar plates. In addition, the inhibitory potential of the extract on the propagation of human pathogenic H5N1-type influenza A virus isolated from a patient and an influenza B virus strain was investigated using MTT and focus assays. Results For the first time, it was shown that a standardized elderberry liquid extract possesses antimicrobial activity against both Gram-positive bacteria of Streptococcus pyogenes and group C and G Streptococci, and the Gram-negative bacterium Branhamella catarrhalis in liquid cultures. The liquid extract also displays an inhibitory effect on the propagation of human pathogenic influenza viruses. Conclusion Rubini elderberry liquid extract is active against human pathogenic bacteria as well as influenza viruses. The activities shown suggest that additional and alternative approaches to combat infections might be provided by this natural product. PMID:21352539

Effect of phenolic compounds on the growth of selected probiotic and pathogenic bacteria.

PubMed

Pacheco-Ordaz, R; Wall-Medrano, A; Goñi, M G; Ramos-Clamont-Montfort, G; Ayala-Zavala, J F; González-Aguilar, G A

2018-01-01

Fruit extracts from different tissues (pulp, seed and peel) have shown antimicrobial and prebiotic activities related to their phenolic profile, although structure-specific evaluations have not been reported yet. The effect of five phenolic compounds (catechin and gallic, vanillic, ferulic and protocatechuic acids) identified in different fruits, particularly in mango, was evaluated on the growth of two probiotic (Lactobacillus rhamnosusGG ATCC 53103 and Lactobacillus acidophilusNRRLB 4495) and two pathogenic (Escherichia coli 0157:H7 ATCC 43890 and Salmonella enterica serovar Typhimurium ATCC 14028) bacteria. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of phenolic acids ranged from 15-20 mmol l -1 and 20-30 mmol l -1 against E. coli and S. Typhimurium, respectively. For catechin, the MIC and MBC were 35 mmol l -1 and >35 mmol l -1 against E. coli and S. Typhimurium, respectively. The presence of catechin and gallic, protocatechuic and vanillic acids in MRS broth without dextrose allowed the growth of lactobacilli. Catechin combined with protocatechuic or vanillic acid mildly allowed the growth of both probiotics. In conclusion, phenolic compounds can selectively inhibit the growth of pathogenic bacteria without affecting the viability of probiotics. This study provides relevant information about the effects of phenolic compounds commonly present in fruit and vegetables on the growth of probiotic and pathogenic bacteria. The compounds selectively allowed the growth of probiotic lactobacilli (Lactobacillus rhamnosus GG and Lactobacillus acidophilus) and inhibited pathogenic bacteria (Escherichia coli and Salmonella Typhimurium) at the same concentration (20 mmol l -1 ). These findings can contribute to the formulation of nutraceutical products, such as synbiotics, that can restore or maintain an optimal composition of human microbiota, potentially improving the overall health of the consumer. © 2017 The Society for Applied Microbiology.

Probiotics and periodontal health

PubMed Central

2011-01-01

Periodontitis is one of the most common chronic inflammatory diseases. The etiology is clearly bacterial and a number of putative bacterial pathogens have been associated with the disease, including Aggregatibacter actinomycetemcomitans, Tannerella forsythus and Porphyromonas gingivalis. Comparatively, little attention has been paid to the identification of health-associated and potentially beneficial bacterial species that may reside in the gingival sulcus. Probiotic technology represents a breakthrough approach to maintaining oral health by using natural beneficial bacteria, commonly found in healthy mouths, to provide a natural defense against those bacteria which are thought to be harmful to teeth and gums. This article endeavors to introduce the concepts of probiotics in periodontics. PMID:22514571

Probiotics and periodontal health.

PubMed

Gupta, G

2011-11-14

Periodontitis is one of the most common chronic inflammatory diseases. The etiology is clearly bacterial and a number of putative bacterial pathogens have been associated with the disease, including Aggregatibacter actinomycetemcomitans, Tannerella forsythus and Porphyromonas gingivalis. Comparatively, little attention has been paid to the identification of health-associated and potentially beneficial bacterial species that may reside in the gingival sulcus. Probiotic technology represents a breakthrough approach to maintaining oral health by using natural beneficial bacteria, commonly found in healthy mouths, to provide a natural defense against those bacteria which are thought to be harmful to teeth and gums. This article endeavors to introduce the concepts of probiotics in periodontics.

Enteric Infections Circulating during Hajj Seasons, 2011–2013

PubMed Central

Alsomali, Mona; Almasri, Malak; Regalado, Eriko Padron; Naeem, Raeece; Tukestani, AbdulHafeez; Asiri, Abdullah; Hill-Cawthorne, Grant A.

2017-01-01

Hajj, the annual Muslim pilgrimage to Mecca, Saudi Arabia, is a unique mass gathering event that raises public health concerns in the host country and globally. Although gastroenteritis and diarrhea are common among Hajj pilgrims, the microbial etiologies of these infections are unknown. We collected 544 fecal samples from pilgrims with medically attended diarrheal illness from 40 countries during the 2011–2013 Hajj seasons and screened the samples for 16 pathogens commonly associated with diarrheal infections. Bacteria were the main agents detected, in 82.9% of the 228 positive samples, followed by viral (6.1%) and parasitic (5.3%) agents. Salmonella spp., Shigella/enteroinvasive Escherichia coli, and enterotoxigenic E. coli were the main pathogens associated with severe symptoms. We identified genes associated with resistance to third-generation cephalosporins ≈40% of Salmonella- and E. coli–positive samples. Hajj-associated foodborne infections pose a major public health risk through the emergence and transmission of antimicrobial drug–resistant bacteria. PMID:28930004

Microbial Biogeography of Public Restroom Surfaces

PubMed Central

Flores, Gilberto E.; Bates, Scott T.; Knights, Dan; Lauber, Christian L.; Stombaugh, Jesse; Knight, Rob; Fierer, Noah

2011-01-01

We spend the majority of our lives indoors where we are constantly exposed to bacteria residing on surfaces. However, the diversity of these surface-associated communities is largely unknown. We explored the biogeographical patterns exhibited by bacteria across ten surfaces within each of twelve public restrooms. Using high-throughput barcoded pyrosequencing of the 16 S rRNA gene, we identified 19 bacterial phyla across all surfaces. Most sequences belonged to four phyla: Actinobacteria, Bacteriodetes, Firmicutes and Proteobacteria. The communities clustered into three general categories: those found on surfaces associated with toilets, those on the restroom floor, and those found on surfaces routinely touched with hands. On toilet surfaces, gut-associated taxa were more prevalent, suggesting fecal contamination of these surfaces. Floor surfaces were the most diverse of all communities and contained several taxa commonly found in soils. Skin-associated bacteria, especially the Propionibacteriaceae, dominated surfaces routinely touched with our hands. Certain taxa were more common in female than in male restrooms as vagina-associated Lactobacillaceae were widely distributed in female restrooms, likely from urine contamination. Use of the SourceTracker algorithm confirmed many of our taxonomic observations as human skin was the primary source of bacteria on restroom surfaces. Overall, these results demonstrate that restroom surfaces host relatively diverse microbial communities dominated by human-associated bacteria with clear linkages between communities on or in different body sites and those communities found on restroom surfaces. More generally, this work is relevant to the public health field as we show that human-associated microbes are commonly found on restroom surfaces suggesting that bacterial pathogens could readily be transmitted between individuals by the touching of surfaces. Furthermore, we demonstrate that we can use high-throughput analyses of bacterial communities to determine sources of bacteria on indoor surfaces, an approach which could be used to track pathogen transmission and test the efficacy of hygiene practices. PMID:22132229

Interactions between the microbiota and pathogenic bacteria in the gut

PubMed Central

Bäumler, Andreas J.; Sperandio, Vanessa

2016-01-01

The microbiome has an important role in human health. Changes in the microbiota can confer resistance to or promote infection by pathogenic bacteria. Antibiotics have a profound impact on the microbiota that alters the nutritional landscape of the gut and can lead to the expansion of pathogenic populations. Pathogenic bacteria exploit microbiota-derived sources of carbon and nitrogen as nutrients and regulatory signals to promote their own growth and virulence. By eliciting inflammation, these bacteria alter the intestinal environment and use unique systems for respiration and metal acquisition to drive their expansion. Unravelling the interactions between the microbiota, the host and pathogenic bacteria will produce strategies for manipulating the microbiota against infectious diseases. PMID:27383983

Interactions between the microbiota and pathogenic bacteria in the gut.

PubMed

Bäumler, Andreas J; Sperandio, Vanessa

2016-07-07

The microbiome has an important role in human health. Changes in the microbiota can confer resistance to or promote infection by pathogenic bacteria. Antibiotics have a profound impact on the microbiota that alters the nutritional landscape of the gut and can lead to the expansion of pathogenic populations. Pathogenic bacteria exploit microbiota-derived sources of carbon and nitrogen as nutrients and regulatory signals to promote their own growth and virulence. By eliciting inflammation, these bacteria alter the intestinal environment and use unique systems for respiration and metal acquisition to drive their expansion. Unravelling the interactions between the microbiota, the host and pathogenic bacteria will produce strategies for manipulating the microbiota against infectious diseases.

Ralstonia solanacearum and R. pseudosolanacearum on Eucalyptus: Opportunists or Primary Pathogens?

PubMed Central

Coutinho, Teresa A.; Wingfield, Michael J.

2017-01-01

Ralstonia solanacearum and R. pseudosolanacearum are well known primary pathogens of herbaceous crops. Reports of wilt caused by these pathogens in tree species are limited other than on Eucalyptus species. Despite the widespread occurrence of so-called bacterial wilt on eucalypts in tropical and sub-tropical parts of Africa, Asia, and the Americas, there remain many contradictions relating to the disease. Our field observations over many years in most regions where the disease occurs on Eucalyptus show that it is always associated with trees that have been subjected to severe stress. The disease is typically diagnosed by immersing cut stems in water and observing bacterial streaming, but the identity of the bacteria within this suspension is seldom considered. To add to the confusion, pathogenicity tests on susceptible species or clones are rarely successful. When they do work, they are on small plants in greenhouse trials. It has become all to easy to attribute Eucalyptus death exclusively to Ralstonia infection. Our data strongly suggest that Ralstonia species and probably other bacteria are latent colonists commonly occurring in healthy and particularly clonally propagated eucalypts. The onset of stress factors provide the bacteria with an opportunity to develop. We believe that the resulting stress weakens the defense systems of the trees allowing Ralstonia and bacterial endophytes to proliferate. Overall our research suggests that R. solanacearum and R. pseudosolanacearum are not primary pathogens of Eucalyptus. Short of clear evidence that they are primary pathogens of Eucalyptus it is inappropriate to attribute this disease solely to infection by Ralstonia species. PMID:28553301

Sources of Bacteria in Outdoor Air across Cities in the Midwestern United States ▿ †

PubMed Central

Bowers, Robert M.; Sullivan, Amy P.; Costello, Elizabeth K.; Collett, Jeff L.; Knight, Rob; Fierer, Noah

2011-01-01

Bacteria are abundant in the atmosphere, where they often represent a major portion of the organic aerosols. Potential pathogens of plants and livestock are commonly dispersed through the atmosphere, and airborne bacteria can have important effects on human health as pathogens or triggers of allergic asthma and seasonal allergies. Despite their importance, the diversity and biogeography of airborne microorganisms remain poorly understood. We used high-throughput pyrosequencing to analyze bacterial communities present in the aerosol fraction containing fine particulate matter of ≤2.5 μm from 96 near-surface atmospheric samples collected from cities throughout the midwestern United States and found that the communities are surprisingly diverse and strongly affected by the season. We also directly compared the airborne communities to those found in hundreds of samples representing potential source environments. We show that, in addition to the more predictable sources (soils and leaf surfaces), fecal material, most likely dog feces, often represents an unexpected source of bacteria in the atmosphere at more urbanized locations during the winter. Airborne bacteria are clearly an important, but understudied, component of air quality that needs to be better integrated into efforts to measure and model pollutants in the atmosphere. PMID:21803902

The role of anaerobic bacteria in the cystic fibrosis airway.

PubMed

Sherrard, Laura J; Bell, Scott C; Tunney, Michael M

2016-11-01

Anaerobic bacteria are not only normal commensals, but are also considered opportunistic pathogens and have been identified as persistent members of the lower airway community in people with cystic fibrosis of all ages and stages of disease. Currently, the role of anaerobic bacteria in cystic fibrosis lower airway disease is not well understood. Therefore, this review describes the recent studies relating to the potential pathophysiological role(s) of anaerobes within the cystic fibrosis lungs. The most frequently identified anaerobic bacteria in the lower airways are common to both cystic fibrosis and healthy lungs. Studies have shown that in cystic fibrosis, the relative abundance of anaerobes fluctuates in the lower airways with reduced lung function and increased inflammation associated with a decreased anaerobic load. However, anaerobes found within the lower airways also produce virulence factors, may cause a host inflammatory response and interact synergistically with recognized pathogens. Anaerobic bacteria are potentially members of the airway microbiota in health but could also contribute to the pathogenesis of lower airway disease in cystic fibrosis via both direct and indirect mechanisms. A personalized treatment strategy that maintains a normal microbial community may be possible in the future.

New and emerging pathogens in canine infectious respiratory disease.

PubMed

Priestnall, S L; Mitchell, J A; Walker, C A; Erles, K; Brownlie, J

2014-03-01

Canine infectious respiratory disease is a common, worldwide disease syndrome of multifactorial etiology. This review presents a summary of 6 viruses (canine respiratory coronavirus, canine pneumovirus, canine influenza virus, pantropic canine coronavirus, canine bocavirus, and canine hepacivirus) and 2 bacteria (Streptococcus zooepidemicus and Mycoplasma cynos) that have been associated with respiratory disease in dogs. For some pathogens a causal role is clear, whereas for others, ongoing research aims to uncover their pathogenesis and contribution to this complex syndrome. Etiology, clinical disease, pathogenesis, and epidemiology are described for each pathogen, with an emphasis on recent discoveries or novel findings.

Effector prediction in host-pathogen interaction based on a Markov model of a ubiquitous EPIYA motif

PubMed Central

2010-01-01

Background Effector secretion is a common strategy of pathogen in mediating host-pathogen interaction. Eight EPIYA-motif containing effectors have recently been discovered in six pathogens. Once these effectors enter host cells through type III/IV secretion systems (T3SS/T4SS), tyrosine in the EPIYA motif is phosphorylated, which triggers effectors binding other proteins to manipulate host-cell functions. The objectives of this study are to evaluate the distribution pattern of EPIYA motif in broad biological species, to predict potential effectors with EPIYA motif, and to suggest roles and biological functions of potential effectors in host-pathogen interactions. Results A hidden Markov model (HMM) of five amino acids was built for the EPIYA-motif based on the eight known effectors. Using this HMM to search the non-redundant protein database containing 9,216,047 sequences, we obtained 107,231 sequences with at least one EPIYA motif occurrence and 3115 sequences with multiple repeats of the EPIYA motif. Although the EPIYA motif exists among broad species, it is significantly over-represented in some particular groups of species. For those proteins containing at least four copies of EPIYA motif, most of them are from intracellular bacteria, extracellular bacteria with T3SS or T4SS or intracellular protozoan parasites. By combining the EPIYA motif and the adjacent SH2 binding motifs (KK, R4, Tarp and Tir), we built HMMs of nine amino acids and predicted many potential effectors in bacteria and protista by the HMMs. Some potential effectors for pathogens (such as Lawsonia intracellularis, Plasmodium falciparum and Leishmania major) are suggested. Conclusions Our study indicates that the EPIYA motif may be a ubiquitous functional site for effectors that play an important pathogenicity role in mediating host-pathogen interactions. We suggest that some intracellular protozoan parasites could secrete EPIYA-motif containing effectors through secretion systems similar to the T3SS/T4SS in bacteria. Our predicted effectors provide useful hypotheses for further studies. PMID:21143776

Expression and crystallization of SeDsbA, SeDsbL and SeSrgA from Salmonella enterica serovar Typhimurium.

PubMed

Jarrott, R; Shouldice, S R; Guncar, G; Totsika, M; Schembri, M A; Heras, B

2010-05-01

Pathogens require protein-folding enzymes to produce functional virulence determinants. These foldases include the Dsb family of proteins, which catalyze oxidative folding in bacteria. Bacterial disulfide catalytic processes have been well characterized in Escherichia coli K-12 and these mechanisms have been extrapolated to other organisms. However, recent research indicates that the K-12 complement of Dsb proteins is not common to all bacteria. Importantly, many pathogenic bacteria have an extended arsenal of Dsb catalysts that is linked to their virulence. To help to elucidate the process of oxidative folding in pathogens containing a wide repertoire of Dsb proteins, Salmonella enterica serovar Typhimurium has been focused on. This Gram-negative bacterium contains three DsbA proteins: SeDsbA, SeDsbL and SeSrgA. Here, the expression, purification, crystallization and preliminary diffraction analysis of these three proteins are reported. SeDsbA, SeDsbL and SeSrgA crystals diffracted to resolution limits of 1.55, 1.57 and 2.6 A and belonged to space groups P2(1), P2(1)2(1)2 and C2, respectively.

Bad bacteria in acute appendicitis: rare but relevant.

PubMed

Reinisch, Alexander; Malkomes, Patrizia; Habbe, Nils; Bechstein, Wolf Otto; Liese, Juliane

2017-09-01

Bacterial infections are a factor for morbidity in patients with acute appendicitis (AA). The spreading of multidrug-resistant (MDR) bacteria is a significant problem in surgery, and the most relevant MDR pathogens are summarized as Enterobacteriaceae, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterococci (ESKAPE) bacteria. Data regarding the species and distribution of bacteria in AA are available, but information about the resistances and their relevance is deficient. In this retrospective study, we analyzed microbiological swabs of patients with AA. The outcome parameters of patients after laparoscopic appendectomy were analyzed against microbiological results, including antibiotic resistance testing. Positive swabs were compared with bacteria cultivated after alternative abdominal emergency surgery (AES). In total, 584 patients with AA were included and had a mean age of 35.5 years. In 216 patients (36.9%), a swab was taken, and in 128 (59.3%) swabs, bacteria could be cultivated. The most frequent organisms were Escherichia coli, Bacteroides species, and Pseudomonas. In 9.4% of the positive AA swabs, MDR germs were cultivated, and all of them were ESKAPE pathogens. Patients with MDR bacteria in AA suffered more infectious complications (p = 0.006) and needed longer hospitalizations (p < 0.009). In AES, aside from appendicitis, a different spectrum containing more MDR bacteria was cultivated (5.9 vs. 20.9%; p < 0.0001). Although they occur less frequently in appendectomy compared to emergency surgeries for other abdominal diseases, MDR bacteria are traceable in this common disease and contribute to additional morbidity.

[Analysis of distribution and drug resistance of pathogens of burn patients during 9 years].

PubMed

Dou, Y; Zhang, Q

2018-03-20

Objective: To investigate distribution and drug resistance of pathogens of burn patients. Methods: A total of 3 357 strains were cultured and isolated from 25 286 specimens of wounds excretion, deep venous catheters, venous blood, stool, mid-stream urine, sputum, puncture fluid, and throat swab of 11 510 burn patients hospitalized in our burn wards from January 2007 to December 2015. After being identified by API bacteria identification panels and automatically bacteria identification equipment, drug-resistances of Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae to 28 common antibiotics were tested by drug sensitivity test with K-B paper disk diffusion method. The WHONET 5.6 software was used to analyze constituent ratio of gram-negative bacteria and gram-positive bacteria in each year, distribution of pathogens in each year, and drug resistance of the above-mentioned 4 pathogens in 9 years to 28 common antibiotics. Data were analyzed by the linear model curve fitting. Results: (1) From 2007 to 2015, constituent ratios of gram-negative bacteria were respectively 41.22% (101/245), 41.88% (165/394), 45.92% (169/368), 42.54% (208/489), 52.35% (267/510), 56.89% (194/341), 58.99% (210/356), 56.95% (172/302), and 50.28% (177/352), with significantly increasing trend ( R (2)=0.625, P <0.05); constituent ratios of gram-positive bacteria were respectively 58.78% (144/245), 58.12% (229/394), 54.08% (199/368), 57.46% (281/489), 47.65% (243/510), 43.11% (147/341), 41.01% (146/356), 43.05% (130/302), 49.72% (175/352), with significantly decreasing trend ( R (2)=0.625, P <0.05). In 9 years, constituent ratio of Staphylococcus aureus ranked the first in all bacteria, and constituent ratios of Pseudomonas aeruginosa and Klebsiella pneumoniae were with significantly increasing trend ( R (2)=0.811, 0.778, P <0.01). (2) In 9 years, drug-resistant rates of Staphylococcus aureus to gentamycin and rifampicin were with significantly decreasing trend ( R (2)=0.727, 0.766, P <0.01); drug-resistant rates of Staphylococcus aureus to phosphonomycin were always in lower levels of 4.6% to 19.5%. In 9 years, drug-resistant rates of Pseudomonas aeruginosa to ceftazidime and ciprofloxacin had no significant change in trend ( R (2)=0.023, <0.001, P >0.05), while drug-resistant rates of Pseudomonas aeruginosa to other 10 common antibiotics were with significantly increasing trend ( R (2)=0.764, 0.793, 0.785, 0.768, 0.752, 0.749, 0.789, 0.786, 0.706, 0.629, P <0.01). In 9 years, drug-resistant rate of Acinetobacter baumannii to ampicillin/sulbactam was with significantly decreasing trend ( R (2)=0.652, P <0.01), and drug-resistant rate of Acinetobacter baumannii to amikacin was with significantly increasing trend ( R (2)=0.531, P <0.05). In 9 years, drug-resistant rates of Klebsiella pneumoniae to piperacillin, ampicillin/sulbactam, cefuroxime, ceftazidime, cefotaxime, cefepime, imipenem, meropenem, amikacin, and gentamicin were with obviously increasing trend ( R (2)=0.481, 0.672, 0.694, 0.532, 0.810, 0.641, 0.809, 0.709, 0.579, 0.810, P <0.05 or P <0.01). Conclusions: Constituent ratios of gram-positive bacteria of Pseudomonas aeruginosa and Klebsiella pneumoniae of burn patients hospitalized in our burn wards from 2007 to 2015 were significantly increased, while constituent ratios of Staphylococcus aureus of those children always ranked the first. Drug-resistence of bacteria of those children in our burn wards was serious. Drug-resistant rate of Staphylococcus aureus only to phosphonomycin was always in lower level. Drug-resistant rates of Pseudomonas aeruginosa to 10 common antibiotics except ceftazidime and ciprofloxacin were significantly increased. Drug-resistant rate of Acinetobacter baumannii only to ampicillin/sulbactam was significantly decreased. Drug-resistant rates of Klebsiella pneumoniae to most common antibiotics were significantly increased.

Relationships and trends of E. Coli, human-associated Bacteroides, and pathogens in the Proctor Creek Watershed

EPA Science Inventory

Urban surface waters can be impacted by anthropogenic sources such as impervious surfaces, sanitary and storm sewers, and failing infrastructure. Fecal indicator bacteria (FIB) and microbial source tracking (MST) markers are common gauges of stream water quality, however, little...

Plant Natural Compounds with Antibacterial Activity Towards Common Pathogens of Pond-Cultured Channel Catfish (Ictalurus punctatus)

USDA-ARS?s Scientific Manuscript database

The bacteria Edwardsiella ictaluri and Flavobacterium columnare cause enteric septicemia and columnaris disease, respectively, in channel catfish (Ictalurus punctatus). Natural therapeutants may provide an alternative to current management approaches used by producers. In this study, a rapid bioas...

SENSITIVITY OF DIFFERENT AEROMONAS SPECIES TO COPPER AND SILVER

EPA Science Inventory

Aeromonas bacteria are common flora in surface and ground waters and are considered to be human pathogens. They can also be found in municipally treated drinking water, likely as a component of biofilms, as found in distribution system pipes and point of use water filters. It ...

Microbial- and isothiocyanate-mediated control of Phytophthora and Pythium species

Treesearch

M.F. Cohen; E. Yamamoto; E. Condeso; B.L. Anacker; N. Rank; M. Mazzola

2008-01-01

Plant pathogens of the oomycete lineage share common susceptibilities to many biotic and abiotic stresses. We are investigating the potential of antagonistic bacteria, isothiocyanates, and mycophagous amoebae to control diseases caused by Phytophthora spp., including the etiologic agent of sudden oak death, Phytophthora ramorum (...

Modulation of cell surface hydrophobicity and attachment of bacteria to abiotic surfaces and shrimp by Malaysian herb extracts.

PubMed

Hui, Yew Woh; Dykes, Gary A

2012-08-01

The use of simple crude water extracts of common herbs to reduce bacterial attachment may be a cost-effective way to control bacterial foodborne pathogens, particularly in developing countries. The ability of water extracts of three common Malaysian herbs (Andrographis paniculata, Eurycoma longifolia, and Garcinia atroviridis) to modulate hydrophobicity and attachment to surfaces of five food-related bacterial strains (Bacillus cereus ATCC 14576, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Salmonella Enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923) were determined. The bacterial attachment to hydrocarbon assay was used to determine bacterial hydrophobicity. Staining and direct microscopic counts were used to determine attachment of bacteria to glass and stainless steel. Plating on selective media was used to determine attachment of bacteria to shrimp. All extracts were capable of either significantly ( P < 0.05) increasing or decreasing bacterial surface hydrophobicity, depending on the herb extract and bacteria combination. Bacterial attachment to all surfaces was either significantly (P < 0.05) increased or decreased, depending on the herb extract and bacteria combination. Overall, hydrophobicity did not show a significant correlation (P > 0.05) to bacterial attachment. For specific combinations of bacteria, surface material, and plant extract, significant correlations (R > 0.80) between hydrophobicity and attachment were observed. The highest of these was observed for S. aureus attachment to stainless steel and glass after treatment with the E. longifolia extract (R = 0.99, P < 0.01). The crude water herb extracts in this study were shown to have the potential to modulate specific bacterial and surface interactions and may, with further work, be useful for the simple and practical control of foodborne pathogens.

[Analysis of Pathogenic Bacteria in Reclaimed Water and Impact of UV Disinfection on the Removal of Pathogenic Bacteria].

PubMed

Jing, Ming; Wang, Lei

2016-02-15

In the study, 454-pyrosequencing technology was employed to investigate the species of pathogenic bacteria and the proportion of each pathogen in secondary effluent. Culture-based, qPCR and Q-RT-PCR methods were employed to analyze the removal of indicator (E. coli) and pathogen (Salmonella and Mycobacterium) by ultraviolet (UV) disinfection at a dose of 60 mJ x Cm(-2). The results showed that 11 kinds of pathogenic bacteria were found and the most abundant potentially pathogenic bacteria in the secondary effluent were affiliated with the genera of Clostridium (2.96%), Arcobacter (0.82%) and Mycobacterium (0.36%). 99.9% of culturable E. coli and Salmonella were removed by UV disinfection (60 mJ x cm(-2), however, less than 90% of culturable Mycobacterium were removed. The removal efficiencies of viable E. coli, Salmonella and Mycobacterium were low. Q-RT-PCR seemed to be a promising method for evaluating viable microorganisms in samples. Besides, pathogenic bacteria entered into VBNC state at a UV dose of 60 mJ x cm(-2). Other advanced treatment processes were needed to ensure safe utilization of reclaimed water.

[Bacteriological aspects of trichomonal vaginitis (author's transl)].

PubMed

Brockmann, J; Höhne, C

1979-01-01

An analysis was made of the vaginal flora of 25 gynaecological patients with acute trichomomal vaginitis, with the view to elucidating the bacteriological situation. Eighty-four isolates, an average of 3.4 per patient, were taken and included a wide range of aerobic and anaerobic bacteria. - Obligate anaerobic species, such as bacteriodes and peptostreptococci, with susceptibility to metronidazole were among the predominant pathogens. - The differentiated susceptibility of the most common bacteria to antibiotics may yield information useful to therapy in the case of aggravated infection.

Antimicrobial activity of fresh garlic juice: An in vitro study

PubMed Central

Yadav, Seema; Trivedi, Niyati A.; Bhatt, Jagat D.

2015-01-01

Introduction: Antimicrobial resistance has been a global concern. Currently, interest has been focused on exploring antimicrobial properties of plants and herbs. One such botanical is Allium sativum (garlic). Aim: To evaluate the antimicrobial activity of fresh juice of garlic. Materials and Methods: Varying concentrations of fresh garlic juice (FGJ) were tested for their antimicrobial activity against common pathogenic organisms isolated at SSG Hospital, Vadodara, using well diffusion method. Moreover, minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of FGJ were tested using broth dilution method. Sensitivity pattern of the conventional antimicrobials against common pathogenic bacteria was tested using disc diffusion method. Results: FGJ produced dose-dependent increase in the zone of inhibition at a concentration of 10% and higher. MIC of FGJ against the pathogens ranged from 4% to 16% v/v whereas MLC value ranged from 4% to 32% v/v with Escherichia coli and Staphylococcus aureus spp. showed highest sensitivity. Conclusion: FGJ has definite antimicrobial activity against common pathogenic organisms isolated at SSG Hospital, Vadodara. Further studies are needed to find out the efficacy, safety, and kinetic data of its active ingredients. PMID:27011724

[The value of glucose-positive coliform bacteria and potentially pathogenic bacteria as indicators of epidemiological safety of tap water].

PubMed

Zhuravlev, P V; Aleshnia, V V; Panasovets, O P; Morozova, A A; Artemova, T Z; Talaeva, Iu G; Zagaĭnova, A V; Gipp, E K

2012-01-01

Due to intensive anthropogenic pollution of water environment generally accepted indicators of epidemic security of water bodies - common bacteria and thermotolerant coliform bacteria do not always permit to obtain an objective characterization of bacterial contamination of tap water. From the point of view of authors the integral index - glucose positive coliform bacteria most adequately reflect the sanitary-hygienic and epidemiological situation of water bodies. In monitoring for bacterial quality of tap water it is advisable to determine glucose positive coliform bacteria, that will provide the relevance of estimation of the epidemiological safety of water use. According to the method developed by the authors the calculation of the index of population risk of acute intestinal infections occurrence in dependence on the quality of tap water in Azov and Tsimlyansk towns.

Comparison of the disinfection efficacy of chlorine-based products for inactivation of viral indicators and pathogenic bacteria in produce wash water.

PubMed

Chaidez, Cristobal; Moreno, Maria; Rubio, Werner; Angulo, Miguel; Valdez, Benigno

2003-09-01

Outbreaks of pathogenic bacteria infections associated with the consumption of fresh produce has occurred with increased frequency in recent years. This study was undertaken to determine the efficacy of three commonly used disinfectants in packing-houses of Culiacan, Mexico (sodium hypochlorite [NaOCl], trichlor-s-triazinetrione [TST] and thrichlormelamine [TCM]) for inactivation of viral indicators and pathogenic bacteria inoculated onto produce wash water. Each microbial challenge consisted of 2 L of water containing approximately 8 log10 bacterial CFU ml(-1), and 8 log10 viral PFU ml(-1) treated with 100 and 300 mg l(-1) of total chlorine with modified turbidity. Water samples were taken after 2 min of contact with chlorine-based products and assayed for the particular microorganisms. TST and NaOCl were found to effectively reduce for bacterial pathogens and viral indicators 8 log10 and 7 log10, respectively (alpha=0.05). The highest inactivation rate was observed when the turbidity was low and the disinfectant was applied at 300 mg l(-1). TCM did not show effective results when compared with the TST and NaOCl (P<0.05). These findings suggest that turbidity created by the organic and inorganic material present in the water tanks carried by the fresh produce may affect the efficacy of the chlorine-based products.

Diversity of the Epsilonproteobacteria Dsb (disulfide bond) systems

PubMed Central

Bocian-Ostrzycka, Katarzyna M.; Grzeszczuk, Magdalena J.; Dziewit, Lukasz; Jagusztyn-Krynicka, Elżbieta K.

2015-01-01

The bacterial proteins of the Dsb family—important components of the post-translational protein modification system—catalyze the formation of disulfide bridges, a process that is crucial for protein structure stabilization and activity. Dsb systems play an essential role in the assembly of many virulence factors. Recent rapid advances in global analysis of bacteria have thrown light on the enormous diversity among bacterial Dsb systems. While the Escherichia coli disulfide bond-forming system is quite well understood, the mechanisms of action of Dsb systems in other bacteria, including members of class Epsilonproteobacteria that contain pathogenic and non-pathogenic bacteria colonizing extremely diverse ecological niches, are poorly characterized. Here we present a review of current knowledge on Epsilonproteobacteria Dsb systems. We have focused on the Dsb systems of Campylobacter spp. and Helicobacter spp. because our knowledge about Dsb proteins of Wolinella and Arcobacter spp. is still scarce and comes mainly from bioinformatic studies. Helicobacter pylori is a common human pathogen that colonizes the gastric epithelium of humans with severe consequences. Campylobacter spp. is a leading cause of zoonotic enteric bacterial infections in most developed and developing nations. We focus on various aspects of the diversity of the Dsb systems and their influence on pathogenicity, particularly because Dsb proteins are considered as potential targets for a new class of anti-virulence drugs to treat human infections by Campylobacter or Helicobacter spp. PMID:26106374

Evaluation of Lactic Acid Bacteria Isolated from Fermented Plant Products for Antagonistic Activity Against Urinary Tract Pathogen Staphylococcus saprophyticus.

PubMed

Tsai, Cheng-Chih; Lai, Tzu-Min; Lin, Pei-Pei; Hsieh, You-Miin

2018-06-01

Urinary tract infections (UTIs) are the most common infectious diseases in infants and the elderly; they are also the most common among nosocomial infections. The treatment of UTIs usually involves a short-term course of antibiotics. The purpose of this study was to identify the strains of lactic acid bacteria (LAB) that can inhibit the urinary tract pathogen Staphylococcus saprophyticus, as alternatives to antibiotics. In this study, we collected 370 LAB strains from fermented plant products and reference strains from the Bioresources Collection and Research Center (BCRC). Using spent culture supernatants (SCS), we then screened these LAB strains with for antimicrobial effects on urinary tract pathogens by the well-diffusion assay. Seven LAB strains-PM2, PM68, PM78, PM201, PM206, PM229, and RY2-exhibited inhibitory activity and were evaluated for anti-growth activity against urinary tract pathogens by the co-culture inhibition assay. Anti-adhesion and anti-invasion activities against urinary tract pathogens were evaluated using the SV-HUC-1 urothelial cell cultures. The results revealed that the survival rate of S. saprophyticus ranged from 0.9-2.96%, with the pH continuously decreasing after co-culture with LAB strains for 4 h. In the competitive adhesion assay, the exclusion and competition groups performed better than the displacement group. In the SV-HUC-1 cell invasion assay, PM201, PM206, PM229, and RY2 were found to inhibit the invasion of SV-HUC-1 cells by S. saprophyticus BCRC 10786. To conclude, RY2, PM229, and PM68 strains exhibited inhibitory activity against the urinary tract pathogen S. saprophyticus.

The target of daptomycin is absent from Escherichia coli and other gram-negative pathogens.

PubMed

Randall, Christopher P; Mariner, Katherine R; Chopra, Ian; O'Neill, Alex J

2013-01-01

Antistaphylococcal agents commonly lack activity against Gram-negative bacteria like Escherichia coli owing to the permeability barrier presented by the outer membrane and/or the action of efflux transporters. When these intrinsic resistance mechanisms are artificially compromised, such agents almost invariably demonstrate antibacterial activity against Gram negatives. Here we show that this is not the case for the antibiotic daptomycin, whose target appears to be absent from E. coli and other Gram-negative pathogens.

Recent development of mass spectrometry and proteomics applications in identification and typing of bacteria.

PubMed

Cheng, Keding; Chui, Huixia; Domish, Larissa; Hernandez, Drexler; Wang, Gehua

2016-04-01

Identification and typing of bacteria occupy a large fraction of time and work in clinical microbiology laboratories. With the certification of some MS platforms in recent years, more applications and tests of MS-based diagnosis methods for bacteria identification and typing have been created, not only on well-accepted MALDI-TOF-MS-based fingerprint matches, but also on solving the insufficiencies of MALDI-TOF-MS-based platforms and advancing the technology to areas such as targeted MS identification and typing of bacteria, bacterial toxin identification, antibiotics susceptibility/resistance tests, and MS-based diagnostic method development on unique bacteria such as Clostridium and Mycobacteria. This review summarizes the recent development in MS platforms and applications in bacteria identification and typing of common pathogenic bacteria. © 2016 The Authors. PROTEOMICS - Clinical Applications Published by WILEY-VCH Verlag GmbH & Co. KGaA.

Effect of air pollution on the total bacteria and pathogenic bacteria in different sizes of particulate matter.

PubMed

Liu, Huan; Zhang, Xu; Zhang, Hao; Yao, Xiangwu; Zhou, Meng; Wang, Jiaqi; He, Zhanfei; Zhang, Huihui; Lou, Liping; Mao, Weihua; Zheng, Ping; Hu, Baolan

2018-02-01

In recent years, air pollution events have occurred frequently in China during the winter. Most studies have focused on the physical and chemical composition of polluted air. Some studies have examined the bacterial bioaerosols both indoors and outdoors. But few studies have focused on the relationship between air pollution and bacteria, especially pathogenic bacteria. Airborne PM samples with different diameters and different air quality index values were collected in Hangzhou, China from December 2014 to January 2015. High-throughput sequencing of 16S rRNA was used to categorize the airborne bacteria. Based on the NCBI database, the "Human Pathogen Database" was established, which is related to human health. Among all the PM samples, the diversity and concentration of total bacteria were lowest in the moderately or heavily polluted air. However, in the PM2.5 and PM10 samples, the relative abundances of pathogenic bacteria were highest in the heavily and moderately polluted air respectively. Considering the PM samples with different particle sizes, the diversities of total bacteria and the proportion of pathogenic bacteria in the PM10 samples were different from those in the PM2.5 and TSP samples. The composition of PM samples with different sizes range may be responsible for the variances. The relative humidity, carbon monoxide and ozone concentrations were the main factors, which affected the diversity of total bacteria and the proportion of pathogenic bacteria. Among the different environmental samples, the compositions of the total bacteria were very similar in all the airborne PM samples, but different from those in the water, surface soil, and ground dust samples. Which may be attributed to that the long-distance transport of the airflow may influence the composition of the airborne bacteria. This study of the pathogenic bacteria in airborne PM samples can provide a reference for environmental and public health researchers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gut bacteria are rarely shared by co-hospitalized premature infants, regardless of necrotizing enterocolitis development

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

Raveh-Sadka, Tali; Thomas, Brian C.; Singh, Andrea

Premature infants are highly vulnerable to aberrant gastrointestinal tract colonization, a process that may lead to diseases like necrotizing enterocolitis. Thus, spread of potential pathogens among hospitalized infants is of great concern. Here, we reconstructed hundreds of high-quality genomes of microorganisms that colonized co-hospitalized premature infants, assessed their metabolic potential, and tracked them over time to evaluate bacterial strain dispersal among infants. We compared microbial communities in infants who did and did not develop necrotizing enterocolitis. Surprisingly, while potentially pathogenic bacteria of the same species colonized many infants, our genome-resolved analysis revealed that strains colonizing each baby were typically distinct.more » In particular, no strain was common to all infants who developed necrotizing enterocolitis. The paucity of shared gut colonizers suggests the existence of significant barriers to the spread of bacteria among infants. Furthermore, we demonstrate that strain-resolved comprehensive community analysis can be accomplished on potentially medically relevant time scales.« less

Gut bacteria are rarely shared by co-hospitalized premature infants, regardless of necrotizing enterocolitis development

DOE PAGES

Raveh-Sadka, Tali; Thomas, Brian C.; Singh, Andrea; ...

2015-03-03

Premature infants are highly vulnerable to aberrant gastrointestinal tract colonization, a process that may lead to diseases like necrotizing enterocolitis. Thus, spread of potential pathogens among hospitalized infants is of great concern. Here, we reconstructed hundreds of high-quality genomes of microorganisms that colonized co-hospitalized premature infants, assessed their metabolic potential, and tracked them over time to evaluate bacterial strain dispersal among infants. We compared microbial communities in infants who did and did not develop necrotizing enterocolitis. Surprisingly, while potentially pathogenic bacteria of the same species colonized many infants, our genome-resolved analysis revealed that strains colonizing each baby were typically distinct.more » In particular, no strain was common to all infants who developed necrotizing enterocolitis. The paucity of shared gut colonizers suggests the existence of significant barriers to the spread of bacteria among infants. Furthermore, we demonstrate that strain-resolved comprehensive community analysis can be accomplished on potentially medically relevant time scales.« less

Gut bacteria are rarely shared by co-hospitalized premature infants, regardless of necrotizing enterocolitis development

PubMed Central

Raveh-Sadka, Tali; Thomas, Brian C; Singh, Andrea; Firek, Brian; Brooks, Brandon; Castelle, Cindy J; Sharon, Itai; Baker, Robyn; Good, Misty; Morowitz, Michael J; Banfield, Jillian F

2015-01-01

Premature infants are highly vulnerable to aberrant gastrointestinal tract colonization, a process that may lead to diseases like necrotizing enterocolitis. Thus, spread of potential pathogens among hospitalized infants is of great concern. Here, we reconstructed hundreds of high-quality genomes of microorganisms that colonized co-hospitalized premature infants, assessed their metabolic potential, and tracked them over time to evaluate bacterial strain dispersal among infants. We compared microbial communities in infants who did and did not develop necrotizing enterocolitis. Surprisingly, while potentially pathogenic bacteria of the same species colonized many infants, our genome-resolved analysis revealed that strains colonizing each baby were typically distinct. In particular, no strain was common to all infants who developed necrotizing enterocolitis. The paucity of shared gut colonizers suggests the existence of significant barriers to the spread of bacteria among infants. Importantly, we demonstrate that strain-resolved comprehensive community analysis can be accomplished on potentially medically relevant time scales. DOI: http://dx.doi.org/10.7554/eLife.05477.001 PMID:25735037

Relationships and trends of E. Coli, human-associated bacteroides, and pathogens in the Proctor Creek watershed (GWRC 2017)

EPA Science Inventory

Urban surface waters can be impacted by anthropogenic sources such as impervious surfaces, sani-tary and storm sewers, and failing infrastructure. Fecal indicator bacteria (FIB) and microbial source tracking (MST) markers are common gauges of stream water qual-ity, however, litt...

Differential Effects of Solar Ultraviolet Radiation on Culturable Enterococcus faecalis and Enterococcus DNA Determined Using Real-time Quantitative PCR

EPA Science Inventory

Biological contamination of aquatic environments by pathogenic microorganisms is often assessed using fecal indicator bacteria such as enterococci. The concentrations of enterococci are commonly determined by culturing techniques, but there has been recent interest in using molec...

Bloodstream infections at a tertiary referral hospital in Yangon, Myanmar.

PubMed

Myat, Tin Ohn; Prasad, Namrata; Thinn, Kyi Kyi; Win, Kyu Kyu; Htike, Wah Win; Zin, Khwar Nyo; Murdoch, David R; Crump, John A

2014-11-01

Data regarding characteristics of bloodstream infections in Myanmar are limited. Blood culture results from all outpatients and inpatients were extracted from records of the Clinical Microbiology Laboratory, Yangon General Hospital, for the period 2005 through 2013. Of 3865 blood cultures performed, 449 (11.6%) were positive for a pathogenic organism. Gram-negative bacteria was the most common organism group, accounting for 246 (55.5%) of 449 isolations. Staphylococcus aureus was the most common isolate, detected in 171 (38.1%) of 449 blood cultures. From 2005-2008 to 2009-2013 the proportion of all pathogenic isolates that were Gram-positive declined from 52.8% (167/316) to 20.3% (27/133) (p<0.001), whereas the proportion of Gram-negative bacteria rose from 45.6% (144/316) to 78.9% (105/133) (p<0.001), with non-fermentative bacilli accounting for much of this increase. Antimicrobial susceptibility testing demonstrated a high prevalence resistance of S. aureus to first-line antimicrobials such as erythromycin, penicillin and oxacillin. More than half of tested Escherichia coli and Citrobacter species showed resistance to amoxicillin-clavulanic acid, ceftriaxone or gentamicin. Bloodstream infections are common among patients receiving blood culture at a tertiary hospital in Yangon, Myanmar. Our findings suggest that antimicrobial resistance among invasive bacteria is common, similar to patterns described elsewhere in the region, and highlight the need for locally adapted antimicrobial guidelines for sepsis management. © The Author 2014. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multistrain Infections with Lyme Borreliosis Pathogens in the Tick Vector.

PubMed

Durand, Jonas; Herrmann, Coralie; Genné, Dolores; Sarr, Anouk; Gern, Lise; Voordouw, Maarten J

2017-02-01

Mixed or multiple-strain infections are common in vector-borne diseases and have important implications for the epidemiology of these pathogens. Previous studies have mainly focused on interactions between pathogen strains in the vertebrate host, but little is known about what happens in the arthropod vector. Borrelia afzelii and Borrelia garinii are two species of spirochete bacteria that cause Lyme borreliosis in Europe and that share a tick vector, Ixodes ricinus Each of these two tick-borne pathogens consists of multiple strains that are often differentiated using the highly polymorphic ospC gene. For each Borrelia species, we studied the frequencies and abundances of the ospC strains in a wild population of I. ricinus ticks that had been sampled from the same field site over a period of 3 years. We used quantitative PCR (qPCR) and 454 sequencing to estimate the spirochete load and the strain diversity within each tick. For B. afzelii, there was a negative relationship between the two most common ospC strains, suggesting the presence of competitive interactions in the vertebrate host and possibly the tick vector. The flat relationship between total spirochete abundance and strain richness in the nymphal tick indicates that the mean abundance per strain decreases as the number of strains in the tick increases. Strains with the highest spirochete load in the nymphal tick were the most common strains in the tick population. The spirochete abundance in the nymphal tick appears to be an important life history trait that explains why some strains are more common than others in nature. Lyme borreliosis is the most common vector-borne disease in the Northern Hemisphere and is caused by spirochete bacteria that belong to the Borrelia burgdorferi sensu lato species complex. These tick-borne pathogens are transmitted among vertebrate hosts by hard ticks of the genus Ixodes Each Borrelia species can be further subdivided into genetically distinct strains. Multiple-strain infections are common in both the vertebrate host and the tick vector and can result in competitive interactions. To date, few studies on multiple-strain vector-borne pathogens have investigated patterns of cooccurrence and abundance in the arthropod vector. We demonstrate that the abundance of a given strain in the tick vector is negatively affected by the presence of coinfecting strains. In addition, our study suggests that the spirochete abundance in the tick is an important life history trait that can explain why some strains are more common in nature than others. Copyright © 2017 American Society for Microbiology.

Genotypic and phenotypic characterization of aerosolized bacteria collected from African dust events

DOE PAGES

Wilson, Christina A.; Brigmon, Robin L.; Yeager, Chris; ...

2013-07-31

Twenty-one bacteria were isolated and characterized from air samples collected in Africa and the Caribbean by the United States Geological Survey (USGS). Isolates were selected based on preliminary characterization as possible pathogens. Identification of the bacterial isolates was 25 achieved using 16S rRNA gene sequence analysis, fatty acid methyl esters (FAMEs) profiling, the BIOLOG Microlog® System (carbon substrate assay), and repetitive extragenic palindromic (REP)-PCR analysis. The majority of isolates (18/21) were identified as species of the genus Bacillus. Three isolates were classified within the Bacillus cereus senso lato group, which includes Bacillus anthracis, Bacillus thuringiensis, and Bacillus cereus strains. Onemore » isolate was identified as a Staphylococcus sp., 30 most closely related to species (i.e Staphylococcus kloosii, Staphylococcus warneri) that are commonly associated with human or animal skin, but can also act as opportunistic pathogen. Another isolate was tentatively identified as Tsukamurella inchonensis, a known respiratory pathogen, and was resistant to the ten antibiotics tested including vancomycin.« less

Are happy chickens safer chickens? Poultry welfare and disease susceptibility.

PubMed

Humphrey, Tom

2006-08-01

1. Contaminated chicken meat remains an internationally important vehicle for human infection with Salmonella and Campylobacter spp. In addition, the last 20 years has seen an international pandemic of human salmonellosis caused by the contamination of eggs with Salmonella Enteritidis. 2. It has been a long held scientific view that Campylobacter spp. and most, if not all of the common zoonotic salmonella, are essentially commensal in chickens. They usually form part of the gut flora and contaminate chicken carcases, for example, by faecal spillage at slaughter. Even when certain salmonella serovars like S. Enteritidis are invasive in laying hens overt evidence of clinical disease is rare and the birds appear to behave normally. 3. Are these bacteria just 'passing through' the avian host and only transient members of the bacterial flora or is there a more dynamic perspective to this infection/colonisation process? Chickens mount antibody responses to both pathogens, which indicate something other than commensalism. Such immune responses, however, do not always result in the clearance of the pathogen. 4. Not all animals in a group will carry salmonella or campylobacter, even under experimental conditions, and will vary, especially those that are outbred, in their responses to pathogen challenge. Identifying the reasons behind this could have important implications for disease control. 5. Both salmonella and campylobacter are more likely to be found in animals, which are compromised and this may explain at least part of the variations seen. Animals are more susceptible to infection when they are in a poor environment, fed a poor diet and/or under physical or psychological stress. 6. Work in this area has naturally focused on pathogens of medical significance and has shown that neurotransmitters such as noradrenaline can markedly alter pathogen behaviour. Other host responses like Interferon gamma can also affect host tissues in a way, which facilitates invasion by pathogens and may also interact directly with certain bacteria. 7. From a food safety perspective, there is evidence that egg contents contamination in ovo may be linked to transient stress in the hen. Current work at the University of Bristol on the epidemiology of campylobacter in broiler production is also showing a potential link between gut health and campylobacter colonisation and challenging the concept that these bacteria are common commensals. 8. The poor economic returns received by the egg and poultry industries mean that intensive production methods are common. Is it possible to rear chickens under these conditions in such a way as to exclude zoonotic pathogens like salmonella and campylobacter? Data from the UK strongly suggest that this is possible with the former pathogen. Can similar advances be achieved with campylobacter?

Antimicrobials from human skin commensal bacteria protect against Staphylococcus aureus and are deficient in atopic dermatitis

PubMed Central

Nakatsuji, Teruaki; Chen, Tiffany H.; Narala, Saisindhu; Chun, Kimberly A.; Two, Aimee M.; Yun, Tong; Shafiq, Faiza; Kotol, Paul F.; Bouslimani, Amina; Melnik, Alexey V.; Latif, Haythem; Kim, Ji-Nu; Lockhart, Alexandre; Artis, Keli; David, Gloria; Taylor, Patricia; Streib, Joanne; Dorrestein, Pieter C.; Grier, Alex; Gill, Steven R.; Zengler, Karsten; Hata, Tissa R.; Leung, Donald Y. M.; Gallo, Richard L.

2017-01-01

The microbiome can promote or disrupt human health by influencing both adaptive and innate immune functions. We tested whether bacteria that normally reside on human skin participate in host defense by killing Staphylococcus aureus, a pathogen commonly found in patients with atopic dermatitis (AD) and an important factor that exacerbates this disease. High-throughput screening for antimicrobial activity against S.aureus was performed on isolates of coagulase-negative Staphylococcus (CoNS) collected from the skin of healthy and AD subjects. CoNS strains with antimicrobial activity were common on the normal population but rare on AD subjects. A low frequency of strains with antimicrobial activity correlated with colonization by S.aureus. The antimicrobial activity was identified as previously unknown antimicrobial peptides (AMPs) produced by CoNS species including Staphylococcus epidermidis and Staphylococcus hominis. These AMPs were strain-specific, highly potent, selectively killed S.aureus, and synergized with the human AMP LL-37. Application of these CoNS strains to mice confirmed their defense function in vivo relative to application of nonactive strains. Strikingly, reintroduction of antimicrobial CoNS strains to human subjects with AD decreased colonization by S.aureus. These findings show how commensal skin bacteria protect against pathogens and demonstrate how dysbiosis of the skin microbiome can lead to disease. PMID:28228596

Pathogen profile of clinical mastitis in Irish milk-recording herds reveals a complex aetiology.

PubMed

Keane, O M; Budd, K E; Flynn, J; McCoy, F

2013-07-06

Effective mastitis control requires knowledge of the predominant pathogen challenges on the farm. In order to quantify this challenge, the aetiological agents associated with clinical mastitis in 30 milk-recording dairy herds in Ireland over a complete lactation were investigated. Standard bacteriology was performed on 630 pretreatment quarter milk samples, of which 56 per cent were culture-positive, 42 per cent culture-negative and 2 per cent contaminated. Two micro-organisms were isolated from almost 5 per cent of the culture-positive samples. The bacteria isolated were Staphylococcus aureus (23 per cent), Streptococcus uberis (17 per cent), Escherichia coli (9 per cent), Streptococcus species (6 per cent), coagulase-negative Staphylococci (4 per cent) and other species (1 per cent). A wide variety of bacterial species were associated with clinical mastitis, with S aureus the most prevalent pathogen overall, followed by S uberis. However, the bacterial challenges varied widely from farm to farm. In comparison with previous reports, in the present study, the contagious pathogens S aureus and Streptococcus agalactiae were less commonly associated with clinical mastitis, whereas, the environmental pathogens S uberis and E coli were found more commonly associated with clinical mastitis. While S aureus remains the pathogen most commonly associated with intramammary infection in these herds, environmental pathogens, such as S uberis and E coli also present a considerable challenge.

Proving the antimicrobial spectrum of an amphoteric surfactant-sol-gel coating: a food-borne pathogen study.

PubMed

Copello, G J; Teves, S; Degrossi, J; D'Aquino, M; Desimone, M F; Díaz, L E

2008-09-01

An antimicrobial coating was evaluated in this work for its antimicrobial efficacy against common food-borne pathogens. Dodecyl-di(aminoethyl)-glycine, an organic disinfectant, was immobilized in a silicon oxide matrix to generate thin films over surfaces by means of the sol-gel process. Tetraethoxysilane was used as the polymeric precursor. No alteration of optical transparency on the covered surfaces was observed. Topographic images obtained with atomic force microscopy showed a homogeneous film with no additional roughness added by the polymer to the surface. The attenuated total reflectance-Fourier transform infrared spectral data showed the presence of dodecyl-di(aminoethyl)-glycine in the silicon oxide network after a normal cleaning procedure. The antimicrobial efficacy test was performed by exposing coated slides to suspensions of common food-borne pathogens: Escherichia coli, Staphyloccocus aureus, E. coli O157:H7, Salmonella typhi, S. cholerasuiss, Listeria innocua and L. monocytogenes. The coating activity was not only bacteriostatic but also bactericidal. The percent reduction of viable microorganism exposure over 24 h to the coated surface ranged between 99.5%, for the more resistant gram-positive bacteria, and over 99.999%, for most gram-negative bacteria. The silicon matrix itself did not account for any reduction of viable microbial, even more an increase was observed.

Antibiotic Management of Lung Infections in Cystic Fibrosis. II. Nontuberculous Mycobacteria, Anaerobic Bacteria, and Fungi

PubMed Central

Aksamit, Timothy R.; Chotirmall, Sanjay H.; Dasenbrook, Elliott C.; Elborn, J. Stuart; LiPuma, John J.; Ranganathan, Sarath C.; Waters, Valerie J.; Ratjen, Felix A.

2014-01-01

Airway infections are a key component of cystic fibrosis (CF) lung disease. Whereas the approach to common pathogens such as Pseudomonas aeruginosa is guided by a significant body of evidence, other infections often pose a considerable challenge to treating physicians. In Part I of this series on the antibiotic management of difficult lung infections, we discussed bacterial organisms including methicillin-resistant Staphylococcus aureus, gram-negative bacterial infections, and treatment of multiple bacterial pathogens. Here, we summarize the approach to infections with nontuberculous mycobacteria, anaerobic bacteria, and fungi. Nontuberculous mycobacteria can significantly impact the course of lung disease in patients with CF, but differentiation between colonization and infection is difficult clinically as coinfection with other micro-organisms is common. Treatment consists of different classes of antibiotics, varies in intensity, and is best guided by a team of specialized clinicians and microbiologists. The ability of anaerobic bacteria to contribute to CF lung disease is less clear, even though clinical relevance has been reported in individual patients. Anaerobes detected in CF sputum are often resistant to multiple drugs, and treatment has not yet been shown to positively affect patient outcome. Fungi have gained significant interest as potential CF pathogens. Although the role of Candida is largely unclear, there is mounting evidence that Scedosporium species and Aspergillus fumigatus, beyond the classical presentation of allergic bronchopulmonary aspergillosis, can be relevant in patients with CF and treatment should be considered. At present, however there remains limited information on how best to select patients who could benefit from antifungal therapy. PMID:25167882

Antibiotic management of lung infections in cystic fibrosis. II. Nontuberculous mycobacteria, anaerobic bacteria, and fungi.

PubMed

Chmiel, James F; Aksamit, Timothy R; Chotirmall, Sanjay H; Dasenbrook, Elliott C; Elborn, J Stuart; LiPuma, John J; Ranganathan, Sarath C; Waters, Valerie J; Ratjen, Felix A

2014-10-01

Airway infections are a key component of cystic fibrosis (CF) lung disease. Whereas the approach to common pathogens such as Pseudomonas aeruginosa is guided by a significant body of evidence, other infections often pose a considerable challenge to treating physicians. In Part I of this series on the antibiotic management of difficult lung infections, we discussed bacterial organisms including methicillin-resistant Staphylococcus aureus, gram-negative bacterial infections, and treatment of multiple bacterial pathogens. Here, we summarize the approach to infections with nontuberculous mycobacteria, anaerobic bacteria, and fungi. Nontuberculous mycobacteria can significantly impact the course of lung disease in patients with CF, but differentiation between colonization and infection is difficult clinically as coinfection with other micro-organisms is common. Treatment consists of different classes of antibiotics, varies in intensity, and is best guided by a team of specialized clinicians and microbiologists. The ability of anaerobic bacteria to contribute to CF lung disease is less clear, even though clinical relevance has been reported in individual patients. Anaerobes detected in CF sputum are often resistant to multiple drugs, and treatment has not yet been shown to positively affect patient outcome. Fungi have gained significant interest as potential CF pathogens. Although the role of Candida is largely unclear, there is mounting evidence that Scedosporium species and Aspergillus fumigatus, beyond the classical presentation of allergic bronchopulmonary aspergillosis, can be relevant in patients with CF and treatment should be considered. At present, however there remains limited information on how best to select patients who could benefit from antifungal therapy.

[Types of microbial contaminants in pharmaceutical raw materials].

PubMed

Martínez-Bermúdez, A; Rodríguez-de Lecea, J; Soto-Esteras, T; Vázquez-Estévez, C; Chena-Cañete, C

1991-01-01

In order to analyze the significance of the microbial content of pharmaceutical raw materials contributed to the finished pharmaceutical products, we have carried out a study of contamination taking into account aerobic bacteria, anaerobic bacteria and fungi. None or only low numbers of pathogenic microorganisms was found in most analyzed products but in some materials, specially those of natural origin, we have detected high bacterial and fungal contamination. Microorganisms of the genus Bacillus have been the aerobic bacteria most frequently isolated; Bifidobacterium and Clostridium were the most common anaerobic bacteria and with respect to the fungi, Penicillium and Aspergillus have been found with the highest frequency. These microorganisms can produce problems in pharmaceutical finished products, due to their enzymatic or toxigenic activities.

Purification and proteomics of pathogen-modified vacuoles and membranes

PubMed Central

Herweg, Jo-Ana; Hansmeier, Nicole; Otto, Andreas; Geffken, Anna C.; Subbarayal, Prema; Prusty, Bhupesh K.; Becher, Dörte; Hensel, Michael; Schaible, Ulrich E.; Rudel, Thomas; Hilbi, Hubert

2015-01-01

Certain pathogenic bacteria adopt an intracellular lifestyle and proliferate in eukaryotic host cells. The intracellular niche protects the bacteria from cellular and humoral components of the mammalian immune system, and at the same time, allows the bacteria to gain access to otherwise restricted nutrient sources. Yet, intracellular protection and access to nutrients comes with a price, i.e., the bacteria need to overcome cell-autonomous defense mechanisms, such as the bactericidal endocytic pathway. While a few bacteria rupture the early phagosome and escape into the host cytoplasm, most intracellular pathogens form a distinct, degradation-resistant and replication-permissive membranous compartment. Intracellular bacteria that form unique pathogen vacuoles include Legionella, Mycobacterium, Chlamydia, Simkania, and Salmonella species. In order to understand the formation of these pathogen niches on a global scale and in a comprehensive and quantitative manner, an inventory of compartment-associated host factors is required. To this end, the intact pathogen compartments need to be isolated, purified and biochemically characterized. Here, we review recent progress on the isolation and purification of pathogen-modified vacuoles and membranes, as well as their proteomic characterization by mass spectrometry and different validation approaches. These studies provide the basis for further investigations on the specific mechanisms of pathogen-driven compartment formation. PMID:26082896

Selection, validation and utility of pathogen surrogate bacteria used in food safety challenge studies: A Review

USDA-ARS?s Scientific Manuscript database

Non-pathogenic surrogate bacteria are prevalently used in a variety of food challenge studies in place of foodborne pathogens such as Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Clostridium botulinum, due to safety and sanitary concerns. Surrogate bacteria should demonstrate si...

Unique characteristics of pyogenic liver abscesses of biliary origin.

PubMed

Shi, Shaohua; Xia, Weiliang; Guo, Haijun; Kong, Haishen; Zheng, Shusen

2016-05-01

Pyrogenic liver abscesses (PLA) can be caused by cholangitis associated with hepatolithiasis and cholangitis related to an abnormal bilioenteric communication, such as a hepaticojejunostomy or the presence of indwelling biliary stents. Our aim was to evaluate the clinical characteristics of PLA of biliary origin. We compared patients with PLA related to biliary tract disease (PLA-B; n = 125) with patients with PLA not related to biliary tract disease (PLA-NB; n = 444). We also separated the patients with PLA-B into PLA related to biliary tract disease that involved an abnormal bilioenteric communication, including hepaticojejunostomy and indwelling biliary stents (PLA-B-AC; n = 38), and PLA-B not related to abnormal communication (n = 87), and compared them. Among the 569 patients with PLA from 2008 to 2013, the most common etiologies were cryptogenic (n = 341; 60%) and biliary (n = 125; 22%). Patients with PLA-B tended to have a higher maximum body temperature and a greater leukocytosis. The incidences of bacteremia, septic shock, death, and postdischarge recurrence were greater in the PLA-B group when compared with the PLA-NB group. The most commonly isolated pathogenic bacteria in PLA-B group were Escherichia coli (36%) and Klebsiella pneumonia (23%). In contrast, in the PLA-NB group, the most common pathogen was K pneumonia (64%), whereas E coli was uncommon (only 5%). Independent risk factors for the occurrence of PLA-B were isolates with multidrug resistant (MDR) bacteria, bacteremia, E coli, and polymicrobial infection. In the group of PLA-B-AC, risk factors included MDR bacteria and a history of malignancy. The occurrences of PLA-B are often infected with MDR bacteria and mixed infections caused mainly by E coli and other isolates and associated with bacteremia; PLA-B-AC are associated with MDR bacteria and a history of malignancy. Copyright © 2016. Published by Elsevier Inc.

[Secretion analysis of pathogenic bacteria culture in 115 rural chronic nasal-sinusitis patients].

PubMed

Zhang, Xiaoyuan; Sun, Jingwu; Chu, Shu

2014-05-01

To investigate the bacteria distribution, drug bacterial sensitivity characteristics of the rural chronic rhinosinusitis (CRS). And to explore the effect of antibiotic on pathogenic bacteria culture. Choose nasal sinus secretions from 115 CRS patients living in rural areas. Aerobic bacteria culture, anaerobic bacteria culture and drug sensitive test were procedured for each sample. At the same time the use of antibiotics nearly 2 months and nearly 2 weeks were collected. Among one hundred and fifteen specimens, 17 kinds of germs were detected in 37 cases, the positive rate of aerobic bacteria was 32.17%. Staphylococcus aureus and epidermis staphylococcus aureus the most common type of aerobe in CRS patients at rural areas. There was negative result in the anaerobic bacteria culture of 17 maxillary sinus specimen. The cases of using antibiotics nearly 2 months was up to 90, accounting for 78.26%. Nearly 2 weeks, 73 cases, accounting for 63.48%. The chi-square analysis showed high bacterial culture rate, in chronic rhinosinusitis with nasal polyps (CRSwNP group), which revealed correlation between bacterial infection factors and nasal polyps formation. For CRS patients with positive result of bacterial culture, they were sensitive to ofloxacin, cefotaxime, organism, ciprofloxacin, magnitude cephalosporin, and were drug fast to penicillin G, ampicillin, erythromycin. No specific differences was found in the bacteria distribution of rural CRS. antibiotics abusage in rural CRS patients and the anaerobic bacteria culture techniques is the main factor resulting in low culture rate. Rational use of antimicrobial agents should be established on the basis of the bacterial culture and drug sensitive test.

Killing of Staphylococcus aureus via Magnetic Hyperthermia Mediated by Magnetotactic Bacteria

PubMed Central

Chen, Changyou; Chen, Linjie; Yi, Yong; Chen, Chuanfang

2016-01-01

Staphylococcus aureus is a common hospital and household pathogen. Given the emergence of antibiotic-resistant derivatives of this pathogen resulting from the use of antibiotics as general treatment, development of alternative therapeutic strategies is urgently needed. Here, we assess the feasibility of killing S. aureus cells in vitro and in vivo through magnetic hyperthermia mediated by magnetotactic bacteria that possess magnetic nanocrystals and demonstrate magnetically steered swimming. The S. aureus suspension was added to magnetotactic MO-1 bacteria either directly or after coating with anti-MO-1 polyclonal antibodies. The suspensions were then subjected to an alternating magnetic field (AMF) for 1 h. S. aureus viability was subsequently assessed through conventional plate counting and flow cytometry. We found that approximately 30% of the S. aureus cells mixed with uncoated MO-1 cells were killed after AMF treatment. Moreover, attachment between the magnetotactic bacteria and S. aureus increased the killing efficiency of hyperthermia to more than 50%. Using mouse models, we demonstrated that magnetic hyperthermia mediated by antibody-coated magnetotactic MO-1 bacteria significantly improved wound healing. These results collectively demonstrated the effective eradication of S. aureus both in vitro and in vivo, indicating the potential of magnetotactic bacterium-mediated magnetic hyperthermia as a treatment for S. aureus-induced skin or wound infections. PMID:26873320

[The significance of glucose positive coliform bacteria and potentially pathogenic bacteria as an indicator of epidemiological safety of tap water].

PubMed

Zhuravlev, P V; Aleshnya, V V; Panasovets, O P; Morozova, A A; Artemova, T Z; Talaeva, Yu G; Zagaynova, A V

2013-01-01

Due to intensive anthropogenic pollution of water environment generally accepted indicators of epidemic security of water bodies--common bacteria (CB) and thermotolerant coliform bacteria (TCB) do not always permit to obtain an objective characterization of bacterial contamination of tap water. From the point of view of authors the integral index--glucose positive coliform bacteria most adequately reflect the sanitary-hygienic and epidemiological situation of water bodies. In monitoring for bacterial quality of tap water it is advisable to determine glucose positive coliform bacteria, that will provide the relevance of estimation of the epidemiological safety of water use. According to the method developed by the authors the calculation of the index of population risk of acute intestinal infections (AHI) occurrence in dependence on the quality of tap water in Azov and Tsimlyansk towns.

Prevalence of potentially pathogenic bacteria as genital pathogens in dairy cattle.

PubMed

Petit, T; Spergser, J; Rosengarten, R; Aurich, J

2009-02-01

Bacteria on the genital mucosa have been studied less in healthy, non-puerperal cows than in cows with puerperal endometritis. We have thus analysed bacteria in swabs from the vagina and cervix of post-puerperal cattle (n = 644). Out of the animals, 6.8% had aborted within the last 12 months, 2.6% and 11.6% showed signs of vaginitis and endometritis, respectively. In 17.2% of cervical swabs pathogenic gram-positive and in 11.5% pathogenic gram-negative bacteria were found. Arcanobacterium pyogenes was isolated from 41.3% of cows with endometritis and from 3.5% without endometritis (p < 0.05). From 12.5% of cows with abortion but from no cow without abortion, Staphylococcus aureus was recovered (p < 0.05). Out of 383 vaginal swabs, 88.3% were positive. In 3.4% of swabs pathogenic gram-positive and in 16.7% pathogenic gram-negative microorganisms were found. The percentage of positive vaginal swabs did not differ between pregnant and non-pregnant animals. In the genital tract, the percentage of swabs positive for normal mucosal bacteria decreased from caudally to cranially (p < 0.05). Pathogenic bacteria were found more often in cervical than in vaginal swabs (p < 0.05). In conclusion, bacteria on the vaginal and cervical mucosa in cattle involve a wide range of species. In animals without endometritis or vaginitis, colonization of the mucosa rather than infection has to be assumed.

Prebiotics: A Potential Treatment Strategy for the Chemotherapy-damaged Gut?

PubMed

Wang, Hanru; Geier, Mark S; Howarth, Gordon S

2016-01-01

Mucositis, characterized by ulcerative lesions along the alimentary tract, is a common consequence of many chemotherapy regimens. Chemotherapy negatively disrupts the intestinal microbiota, resulting in increased numbers of potentially pathogenic bacteria, such as Clostridia and Enterobacteriaceae, and decreased numbers of "beneficial" bacteria, such as Lactobacilli and Bifidobacteria. Agents capable of restoring homeostasis in the bowel microbiota could, therefore, be applicable to mucositis. Prebiotics are indigestible compounds, commonly oligosaccharides, that seek to reverse chemotherapy-induced intestinal dysbiosis through selective colonization of the intestinal microbiota by probiotic bacteria. In addition, evidence is emerging that certain prebiotics contribute to nutrient digestibility and absorption, modulate intestinal barrier function through effects on mucin expression, and also modify mucosal immune responses, possibly via inflammasome-mediated processes. This review examines the known mechanisms of prebiotic action, and explores their potential for reducing the severity of chemotherapy-induced mucositis in the intestine.

Protein Chips for Detection of Salmonella spp. from Enrichment Culture

PubMed Central

Poltronieri, Palmiro; Cimaglia, Fabio; De Lorenzis, Enrico; Chiesa, Maurizio; Mezzolla, Valeria; Reca, Ida Barbara

2016-01-01

Food pathogens are the cause of foodborne epidemics, therefore there is a need to detect the pathogens in food productions rapidly. A pre-enrichment culture followed by selective agar plating are standard detection methods. Molecular methods such as qPCR have provided a first rapid protocol for detection of pathogens within 24 h of enrichment culture. Biosensors also may provide a rapid tool to individuate a source of Salmonella contamination at early times of pre-enrichment culture. Forty mL of Salmonella spp. enrichment culture were processed by immunoseparation using the Pathatrix, as in AFNOR validated qPCR protocols. The Salmonella biosensor combined with immunoseparation showed a limit of detection of 100 bacteria/40 mL, with a 400 fold increase to previous results. qPCR analysis requires processing of bead-bound bacteria with lysis buffer and DNA clean up, with a limit of detection of 2 cfu/50 μL. Finally, a protein chip was developed and tested in screening and identification of 5 common pathogen species, Salmonella spp., E. coli, S. aureus, Campylobacter spp. and Listeria spp. The protein chip, with high specificity in species identification, is proposed to be integrated into a Lab-on-Chip system, for rapid and reproducible screening of Salmonella spp. and other pathogen species contaminating food productions. PMID:27110786

Role of the sseK1 gene in the pathogenicity of Salmonella enterica serovar enteritidis in vitro and in vivo.

PubMed

Yang, Yadong; Yu, Chuan; Ding, Ke; Zhang, Chunjie; Liao, Chengshui; Jia, Yanyan; Li, Jing; Cheng, Xiangchao

2018-04-01

Salmonella enteritidis is a common food-borne pathogen associated with consumption of contaminated poultry meat and eggs, which frequently causes gastroenteritis in humans. Salmonella secreted effector K1 (SseK1), as a translocated and secreted protein has been identified to be essential for the virulence of Salmonella typhimurium in host cells. However, the role of the sseK1 gene in the pathogenicity of S. enteritidis remain unclear. In this study, a sseK1 deletion mutant of S. enteritidis was constructed and its biological characteristics were examined. It was found that the sseK1 deletion mutant did not affect the growth, adherence and invasion of Salmonella enteritidis when compared to the wild-type S. enteritidis. However, the mutant showed decreased formation of biofilm and significantly reduced intracellular survival of bacteria in activated mouse peritoneal macrophages, as well as showed reduced pathogenicity to a murine model by increasing the lethal dose 50% (LD 50 ) value and decreasing the proliferation ratio of bacteria in vivo. Taken together, this study determined an important role for SseK1 in the pathogenicity of S. enteritidis in vitro and in vivo. Copyright © 2018 Elsevier Ltd. All rights reserved.

Candida krusei isolated from fruit juices ultrafiltration membranes promotes colonization of Escherichia coli O157:H7 and Salmonella enterica on stainless steel surfaces.

PubMed

Tarifa, María Clara; Lozano, Jorge Enrique; Brugnoni, Lorena Inés

2017-02-01

To clarify the interactions between a common food spoilage yeast and two pathogenic bacteria involved in outbreaks associated with fruit juices, the present paper studies the effect of the interplay of Candida krusei, collected from UF membranes, with Escherichia coli O157:H7 and Salmonella enterica in the overall process of adhesion and colonization of abiotic surfaces. Two different cases were tested: a) co-adhesion by pathogenic bacteria and yeasts, and b) incorporation of bacteria to pre-adhered C. krusei cells. Cultures were made on stainless steel at 25°C using apple juice as culture medium. After 24 h of co-adhesion with C. krusei, both E. coli O157:H7 and S. enterica increased their counts 1.05 and 1.11 log CFU cm 2 , respectively. Similar increases were obtained when incorporating bacteria to pre-adhered cells of Candida. Nevertheless C. krusei counts decreased in both experimental conditions, in a) 0.40 log CFU cm 2 and 0.55 log CFU cm 2 when exposed to E. coli O157:H7 and S. enterica and in b) 0.18 and 0.68 log CFU cm 2 , respectively. This suggests that C. krusei, E. coli O157:H7, and S. enterica have a complex relationship involving physical and chemical interactions on food contact surfaces. This study supports the possibility that pathogen interactions with members of spoilage microbiota, such as C. krusei, might play an important role for the survival and dissemination of E. coli O157:H7 and Salmonella enterica in food-processing environments. Based on the data obtained from the present study, much more attention should be given to prevent the contamination of these pathogens in acidic drinks.

Etiology and outcome of community-acquired lung abscess.

PubMed

Takayanagi, Noboru; Kagiyama, Naho; Ishiguro, Takashi; Tokunaga, Daidou; Sugita, Yutaka

2010-01-01

Anaerobes are the first and Streptococcus species the second most common cause of community-acquired lung abscess (CALA) in the West. The etiologic pathogens of this disease have changed in Taiwan, with Klebsiella pneumoniae being reported as the most common cause of CALA. To determine the etiologies of community-acquired lung abscess. We retrospectively reviewed the records of 205 Japanese adult patients with CALA to evaluate etiologies and outcomes. We used not only traditional microbiological investigations but also percutaneous ultrasonography-guided transthoracic needle aspiration and protected specimen brushes. Of these 205 patients, 122 had documented bacteriological results, with 189 bacterial species isolated. Pure aerobic, mixed aerobic and anaerobic, and pure anaerobic bacteria were isolated in 90 (73.8%), 17 (13.9%), and 15 (12.3%) patients, respectively. The four most common etiologic pathogens were Streptococcus species (59.8%), anaerobes (26.2%), Gemella species (9.8%), and K. pneumoniae (8.2%). Streptococcus mitis was the most common among the Streptococcus species. Mean duration of antibiotic administration was 26 days. Six patients (2.9%, 3 with actinomycosis and 3 with nocardiosis) were treated with antibiotics for 76-189 days. Two patients with anaerobic lung abscess died. The first and second most common etiologic pathogens of CALA in our hospital were Streptococcus species and anaerobes, respectively. The etiologies in our study differ from those in Taiwan and are similar to those in the West with the exception that Streptococcus species were the most common etiologic pathogens in our study whereas anaerobes are the most frequent etiologic pathogens in Western countries. S. mitis and Gemella species are important etiologic pathogens as well. The identification of Actinomyces and Nocardia is important in order to define the adequate duration of antibiotic administration. Copyright 2010 S. Karger AG, Basel.

Strategies toward vaccines against Burkholderia mallei and Burkholderia pseudomallei.

PubMed

Bondi, Sara K; Goldberg, Joanna B

2008-11-01

Burkholderia mallei and Burkholderia pseudomallei are Gram-negative, rod-shaped bacteria, and are the causative agents of the diseases glanders and melioidosis, respectively. These bacteria have been recognized as important pathogens for over 100 years, yet a relative dearth of available information exists regarding their virulence determinants and immunopathology. Infection with either of these bacteria presents with nonspecific symptoms and can be either acute or chronic, impeding rapid diagnosis. The lack of a vaccine for either bacterium also makes them potential candidates for bioweaponization. Together with their high rate of infectivity via aerosols and resistance to many common antibiotics, both bacteria have been classified as category B priority pathogens by the US NIH and US CDC, which has spurred a dramatic increase in interest in these microorganisms. Attempts have been made to develop vaccines for these infections, which would not only benefit military personnel, a group most likely to be targeted in an intentional release, but also individuals who may come in contact with glanders-infected animals or live in areas where melioidosis is endemic. This review highlights some recent attempts of vaccine development for these infections and the strategies used to improve the efficacy of vaccine approaches.

Strategies toward vaccines against Burkholderia mallei and Burkholderia pseudomallei

PubMed Central

Bondi, Sara K; Goldberg, Joanna B

2009-01-01

Burkholderia mallei and Burkholderia pseudomallei are Gram-negative, rod-shaped bacteria, and are the causative agents of the diseases glanders and melioidosis, respectively. These bacteria have been recognized as important pathogens for over 100 years, yet a relative dearth of available information exists regarding their virulence determinants and immunopathology. Infection with either of these bacteria presents with nonspecific symptoms and can be either acute or chronic, impeding rapid diagnosis. The lack of a vaccine for either bacterium also makes them potential candidates for bioweaponization. Together with their high rate of infectivity via aerosols and resistance to many common antibiotics, both bacteria have been classified as category B priority pathogens by the US NIH and US CDC, which has spurred a dramatic increase in interest in these microorganisms. Attempts have been made to develop vaccines for these infections, which would not only benefit military personnel, a group most likely to be targeted in an intentional release, but also individuals who may come in contact with glanders-infected animals or live in areas where melioidosis is endemic. This review highlights some recent attempts of vaccine development for these infections and the strategies used to improve the efficacy of vaccine approaches. PMID:18980539

Bioassay-directed isolation and evaluation of Harmine from the terrestrial plant Peganum harmala L. for antibacterial activity against Flavobacterium columnare

USDA-ARS?s Scientific Manuscript database

The antibacterial activities of crude extracts obtained from the aerial portions and roots of Peganum harmala L. were evaluated against the common fish pathogenic bacteria species Edwardsiella ictaluri, Flavobacterium columnare, and Streptococcus iniae using a rapid bioassay. Enteric septicemia of c...

Zebrafish and Streptococcal Infections.

PubMed

Saralahti, A; Rämet, M

2015-09-01

Streptococcal bacteria are a versatile group of gram-positive bacteria capable of infecting several host organisms, including humans and fish. Streptococcal species are common colonizers of the human respiratory and gastrointestinal tract, but they also cause some of the most common life-threatening, invasive infections in humans and aquaculture. With its unique characteristics and efficient tools for genetic and imaging applications, the zebrafish (Danio rerio) has emerged as a powerful vertebrate model for infectious diseases. Several zebrafish models introduced so far have shown that zebrafish are suitable models for both zoonotic and human-specific infections. Recently, several zebrafish models mimicking human streptococcal infections have also been developed. These models show great potential in providing novel information about the pathogenic mechanisms and host responses associated with human streptococcal infections. Here, we review the zebrafish infection models for the most relevant streptococcal species: the human-specific Streptococcus pneumoniae and Streptococcus pyogenes, and the zoonotic Streptococcus iniae and Streptococcus agalactiae. The recent success and the future potential of these models for the study of host-pathogen interactions in streptococcal infections are also discussed. © 2015 The Foundation for the Scandinavian Journal of Immunology.

Type-IVC Secretion System: A Novel Subclass of Type IV Secretion System (T4SS) Common Existing in Gram-Positive Genus Streptococcus

PubMed Central

Chen, Chen; Gao, George F.

2012-01-01

A growing number of pathogens are being found to possess specialized secretion systems which they use in various ways to subvert host defenses. Type IV secretion system (T4SS) is one of versatile secretion systems essential for the virulence and even survival of some bacteria species, and they enable the secretion of protein and DNA substrates across the cell envelope. T4SS was once believed to be present only in Gram-negative bacteria. In this study, we present evidence of a new subclass of T4SS, Type-IVC secretion system and indicate its common existence in the Gram-positive bacterial genus Streptococcus. We further identified that VirB1, VirB4, VirB6 and VirD4 are the minimal key components of this system. Using genome comparisons and evolutionary relationship analysis, we proposed that Type-IVC secretion system is movable via transposon factors and mediates the conjugative transfer of DNA, enhances bacterial pathogenicity, and could cause large-scale outbreaks of infections in humans. PMID:23056296

Ankyrin-repeat containing proteins of microbes: a conserved structure with functional diversity

PubMed Central

Al-Khodor, Souhaila; Price, Christopher T.; Kalia, Awdhesh; Kwaik, Yousef Abu

2009-01-01

Summary The ankyrin repeat (ANK) is the most common protein-protein interaction motif in nature and predominantly found in eukaryotic proteins. The genome sequencing of various pathogenic or symbiotic bacteria and eukaryotic viruses identified numerous genes encoding ANK-containing proteins that were proposed to have been acquired from eukaryotes by horizontal gene transfer. However, the recent discovery of additional ANK-containing proteins encoded in the genomes of archaea and free-living bacteria suggests either a more ancient origin of the ANK motif or multiple convergent evolution events. Many bacterial pathogens employ various types of secretion systems to deliver ANK-containing proteins into eukaryotic cells where they mimic or manipulate various host functions. Understanding the molecular and biochemical functions of this family of proteins will enhance our understanding of important host-microbe interactions. PMID:19962898

Synthesis and characterization of silver nanoparticles using Bacillus amyloliquefaciens and Bacillus subtilis to control filarial vector Culex pipiens pallens and its antimicrobial activity.

PubMed

Fouad, Hatem; Hongjie, Li; Yanmei, Ding; Baoting, Yu; El-Shakh, Ahmed; Abbas, Ghulam; Jianchu, Mo

2017-11-01

Culex pipiens pallens are the most common mosquito's vector in Asia. In order to protect the people from diseases, the anti-mosquito population is necessary that uses safe and new bio-pesticides such as bacteria-AgNPs. In our report, we used two kinds of bacteria to synthesize silver nanoparticles to examine the toxic effect on the larvae and pupae of Cx. pipiens pallens and also used as antimicrobial activity. The biosynthesis of AgNPs and its characterization was carried out by UV-Vis spectrophotometry, FTIR, TEM, SEM, and EDX. The larvicidal and pupicidal assays revealed that the lethal concentration LC 50 values of Bacillus amyloliquefaciens-AgNPs were 0.72 ppm (I), 0.73 ppm (II), 0.69 ppm (III), 1.16 ppm (IV), and 4.18 (Pupae), while LC 50 values of Bacillus subtilis-AgNPs were 0.60 ppm (I), 0.62 ppm (II), 0.21 ppm (III), 0.28 ppm (IV), and 3.46 ppm (Pupae) after 72 h of exposure. Antibacterial activity test of AgNPs reveals better results against rice pathogenic bacteria than bacteria alone. Thus, bacteria-mediated silver nanoparticles have a rapid effect on vector mosquito and microbial pathogen suggesting savings of energy and resources. Hence, bacteria-AgNPs may be used in the future as an effective weapon to control vector mosquito and harmful bacteria.

Frontiers for research on the ecology of plant-pathogenic bacteria: fundamentals for sustainability: Challenges in Bacterial Molecular Plant Pathology.

PubMed

Morris, Cindy E; Barny, Marie-Anne; Berge, Odile; Kinkel, Linda L; Lacroix, Christelle

2017-02-01

Methods to ensure the health of crops owe their efficacy to the extent to which we understand the ecology and biology of environmental microorganisms and the conditions under which their interactions with plants lead to losses in crop quality or yield. However, in the pursuit of this knowledge, notions of the ecology of plant-pathogenic microorganisms have been reduced to a plant-centric and agro-centric focus. With increasing global change, i.e. changes that encompass not only climate, but also biodiversity, the geographical distribution of biomes, human demographic and socio-economic adaptations and land use, new plant health problems will emerge via a range of processes influenced by these changes. Hence, knowledge of the ecology of plant pathogens will play an increasingly important role in the anticipation and response to disease emergence. Here, we present our opinion on the major challenges facing the study of the ecology of plant-pathogenic bacteria. We argue that the discovery of markedly novel insights into the ecology of plant-pathogenic bacteria is most likely to happen within a framework of more extensive scales of space, time and biotic interactions than those that currently guide much of the research on these bacteria. This will set a context that is more propitious for the discovery of unsuspected drivers of the survival and diversification of plant-pathogenic bacteria and of the factors most critical for disease emergence, and will set the foundation for new approaches to the sustainable management of plant health. We describe the contextual background of, justification for and specific research questions with regard to the following challenges: Development of terminology to describe plant-bacterial relationships in terms of bacterial fitness. Definition of the full scope of the environments in which plant-pathogenic bacteria reside or survive. Delineation of pertinent phylogenetic contours of plant-pathogenic bacteria and naming of strains independent of their presumed life style. Assessment of how traits of plant-pathogenic bacteria evolve within the overall framework of their life history. Exploration of possible beneficial ecosystem services contributed to by plant-pathogenic bacteria. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Comparative Review of Antimicrobial Resistance in Humans and Nonhuman Primates.

PubMed

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

2018-04-02

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

Comparative Review of Antimicrobial Resistance in Humans and Nonhuman Primates.

PubMed

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

2019-03-01

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

Opportunistic pathogens and elements of the resistome that are common in bottled mineral water support the need for continuous surveillance.

PubMed

Falcone-Dias, Maria Fernanda; Centrón, Daniela; Pavan, Fernando; Moura, Adriana Candido da Silva; Naveca, Felipe Gomes; de Souza, Victor Costa; Farache Filho, Adalberto; Leite, Clarice Queico Fujimura

2015-01-01

Several differences concerning bacterial species, opportunistic pathogens, elements of the resistome as well as variations concerning the CFU/mL counts were identified in some of the five most marketed bottled mineral water from Araraquara city, São Paulo, Brazil. Two out of five brands tested were confirmed as potential source of opportunistic pathogens, including Mycobacterium gordonae, Ralstonia picketti and Burkholderia cepacia complex (Bcc). A total of one hundred and six isolates were recovered from four of these bottled mineral water brands. Betaproteobacteria was predominant followed by Alphaproteobacteria, Gammaproteobacteria and Firmicutes. Ninety percent of the bacteria isolated demonstrated resistance to seventeen of the nineteen antimicrobials tested. These antimicrobials included eight different classes, including 3rd and 4th generation cephalosporins, carbapenems and fluoroquinolones. Multidrug resistant bacteria were detected for fifty-nine percent of isolates in three water brands at counts up to 103 CFU/ml. Of major concern, the two bottled mineral water harboring opportunistic pathogens were also source of elements of the resistome that could be directly transferred to humans. All these differences found among brands highlight the need for continuous bacteriological surveillance of bottled mineral water.

Opportunistic Pathogens and Elements of the Resistome that Are Common in Bottled Mineral Water Support the Need for Continuous Surveillance

PubMed Central

Falcone-Dias, Maria Fernanda; Centrón, Daniela; Pavan, Fernando; Moura, Adriana Candido da Silva; Naveca, Felipe Gomes; de Souza, Victor Costa; Farache Filho, Adalberto; Leite, Clarice Queico Fujimura

2015-01-01

Several differences concerning bacterial species, opportunistic pathogens, elements of the resistome as well as variations concerning the CFU/mL counts were identified in some of the five most marketed bottled mineral water from Araraquara city, São Paulo, Brazil. Two out of five brands tested were confirmed as potential source of opportunistic pathogens, including Mycobacterium gordonae, Ralstonia picketti and Burkholderia cepacia complex (Bcc). A total of one hundred and six isolates were recovered from four of these bottled mineral water brands. Betaproteobacteria was predominant followed by Alphaproteobacteria, Gammaproteobacteria and Firmicutes. Ninety percent of the bacteria isolated demonstrated resistance to seventeen of the nineteen antimicrobials tested. These antimicrobials included eight different classes, including 3rd and 4th generation cephalosporins, carbapenems and fluoroquinolones. Multidrug resistant bacteria were detected for fifty-nine percent of isolates in three water brands at counts up to 103 CFU/ml. Of major concern, the two bottled mineral water harboring opportunistic pathogens were also source of elements of the resistome that could be directly transferred to humans. All these differences found among brands highlight the need for continuous bacteriological surveillance of bottled mineral water. PMID:25803794

An eight-year review of blood culture and susceptibility among sepsis cases in an emergency department in Northeastern Malaysia.

PubMed

Hashairi, F; Hasan, H; Azlan, K; Deris, Z Z

2011-12-01

An understanding of common pathogens and their antibiotic sensitivity patterns is critical for proper management of sepsis in Emergency Department (ED). The goal of the study was to identify common organisms isolated from blood cultures of patients attended to ED and their antimicrobial susceptibility. Beginning from 2002, all cases of positive blood culture collected by the ED, Hospital Universiti Sains Malaysia (HUSM) were recorded and analysed. Over the period of eight years, we documented 995 cases of positive blood cultures. Of these samples, 549 (55.2%) were Gram-negative bacteria; 419 (42.1%) were Gram-positive bacteria; 10 (1.0%) were anaerobic organisms; 10 (1.0%) were fungus; and 7 (0.7%) cases were mixed organisms. Gram-negative bacteria were observed to develop more resistance to antimicrobial agents, especially those commonly used in an outpatient setting with less than 80% sensitivity to ampicillin, cotrimoxazole and ciprofloxacin. By contrast, there has been no marked change in the sensitivity trends of Gram-positive bacteria over the same period. In conclusion, ED physicians are more equipped to initiate empirical antimicrobial therapy especially when dealing with possibility of Gram-negative sepsis.

Regulating the Intersection of Metabolism and Pathogenesis in Gram-positive Bacteria

PubMed Central

RICHARDSON, ANTHONY R.; SOMERVILLE, GREG A.; SONENSHEIN, ABRAHAM L.

2015-01-01

Pathogenic bacteria must contend with immune systems that actively restrict the availability of nutrients and cofactors, and create a hostile growth environment. To deal with these hostile environments, pathogenic bacteria have evolved or acquired virulence determinants that aid in the acquisition of nutrients. This connection between pathogenesis and nutrition may explain why regulators of metabolism in nonpathogenic bacteria are used by pathogenic bacteria to regulate both metabolism and virulence. Such coordinated regulation is presumably advantageous because it conserves carbon and energy by aligning synthesis of virulence determinants with the nutritional environment. In Gram-positive bacterial pathogens, at least three metabolite-responsive global regulators, CcpA, CodY, and Rex, have been shown to coordinate the expression of metabolism and virulence genes. In this chapter, we discuss how environmental challenges alter metabolism, the regulators that respond to this altered metabolism, and how these regulators influence the host-pathogen interaction. PMID:26185086

Biofilm in endodontics: A review

PubMed Central

Jhajharia, Kapil; Parolia, Abhishek; Shetty, K Vikram; Mehta, Lata Kiran

2015-01-01

Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the mechanisms of biofilms’ formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to identify biofilms. PMID:25767760

The Genome of the Amoeba Symbiont “Candidatus Amoebophilus asiaticus” Reveals Common Mechanisms for Host Cell Interaction among Amoeba-Associated Bacteria ▿ †‡

PubMed Central

Schmitz-Esser, Stephan; Tischler, Patrick; Arnold, Roland; Montanaro, Jacqueline; Wagner, Michael; Rattei, Thomas; Horn, Matthias

2010-01-01

Protozoa play host for many intracellular bacteria and are important for the adaptation of pathogenic bacteria to eukaryotic cells. We analyzed the genome sequence of “Candidatus Amoebophilus asiaticus,” an obligate intracellular amoeba symbiont belonging to the Bacteroidetes. The genome has a size of 1.89 Mbp, encodes 1,557 proteins, and shows massive proliferation of IS elements (24% of all genes), although the genome seems to be evolutionarily relatively stable. The genome does not encode pathways for de novo biosynthesis of cofactors, nucleotides, and almost all amino acids. “Ca. Amoebophilus asiaticus” encodes a variety of proteins with predicted importance for host cell interaction; in particular, an arsenal of proteins with eukaryotic domains, including ankyrin-, TPR/SEL1-, and leucine-rich repeats, which is hitherto unmatched among prokaryotes, is remarkable. Unexpectedly, 26 proteins that can interfere with the host ubiquitin system were identified in the genome. These proteins include F- and U-box domain proteins and two ubiquitin-specific proteases of the CA clan C19 family, representing the first prokaryotic members of this protein family. Consequently, interference with the host ubiquitin system is an important host cell interaction mechanism of “Ca. Amoebophilus asiaticus”. More generally, we show that the eukaryotic domains identified in “Ca. Amoebophilus asiaticus” are also significantly enriched in the genomes of other amoeba-associated bacteria (including chlamydiae, Legionella pneumophila, Rickettsia bellii, Francisella tularensis, and Mycobacterium avium). This indicates that phylogenetically and ecologically diverse bacteria which thrive inside amoebae exploit common mechanisms for interaction with their hosts, and it provides further evidence for the role of amoebae as training grounds for bacterial pathogens of humans. PMID:20023027

The genome of the amoeba symbiont "Candidatus Amoebophilus asiaticus" reveals common mechanisms for host cell interaction among amoeba-associated bacteria.

PubMed

Schmitz-Esser, Stephan; Tischler, Patrick; Arnold, Roland; Montanaro, Jacqueline; Wagner, Michael; Rattei, Thomas; Horn, Matthias

2010-02-01

Protozoa play host for many intracellular bacteria and are important for the adaptation of pathogenic bacteria to eukaryotic cells. We analyzed the genome sequence of "Candidatus Amoebophilus asiaticus," an obligate intracellular amoeba symbiont belonging to the Bacteroidetes. The genome has a size of 1.89 Mbp, encodes 1,557 proteins, and shows massive proliferation of IS elements (24% of all genes), although the genome seems to be evolutionarily relatively stable. The genome does not encode pathways for de novo biosynthesis of cofactors, nucleotides, and almost all amino acids. "Ca. Amoebophilus asiaticus" encodes a variety of proteins with predicted importance for host cell interaction; in particular, an arsenal of proteins with eukaryotic domains, including ankyrin-, TPR/SEL1-, and leucine-rich repeats, which is hitherto unmatched among prokaryotes, is remarkable. Unexpectedly, 26 proteins that can interfere with the host ubiquitin system were identified in the genome. These proteins include F- and U-box domain proteins and two ubiquitin-specific proteases of the CA clan C19 family, representing the first prokaryotic members of this protein family. Consequently, interference with the host ubiquitin system is an important host cell interaction mechanism of "Ca. Amoebophilus asiaticus". More generally, we show that the eukaryotic domains identified in "Ca. Amoebophilus asiaticus" are also significantly enriched in the genomes of other amoeba-associated bacteria (including chlamydiae, Legionella pneumophila, Rickettsia bellii, Francisella tularensis, and Mycobacterium avium). This indicates that phylogenetically and ecologically diverse bacteria which thrive inside amoebae exploit common mechanisms for interaction with their hosts, and it provides further evidence for the role of amoebae as training grounds for bacterial pathogens of humans.

Temperature-Dependent Gentamicin Resistance of Francisella tularensis is Mediated by Uptake Modulation

PubMed Central

Loughman, Kathleen; Hall, Jesse; Knowlton, Samantha; Sindeldecker, Devin; Gilson, Tricia; Schmitt, Deanna M.; Birch, James W.-M.; Gajtka, Tara; Kobe, Brianna N.; Florjanczyk, Aleksandr; Ingram, Jenna; Bakshi, Chandra S.; Horzempa, Joseph

2016-01-01

Gentamicin (Gm) is an aminoglycoside commonly used to treat bacterial infections such as tularemia – the disease caused by Francisella tularensis. In addition to being pathogenic, F. tularensis is found in environmental niches such as soil where this bacterium likely encounters Gm producers (Micromonospora sp.). Here we show that F. tularensis exhibits increased resistance to Gm at ambient temperature (26°C) compared to mammalian body temperature (37°C). To evaluate whether F. tularensis was less permeable to Gm at 26°C, a fluorescent marker [Texas Red (Tr)] was conjugated with Gm, yielding Tr-Gm. Bacteria incubated at 26°C showed reduced fluorescence compared to those at 37°C when exposed to Tr-Gm suggesting that uptake of Gm was reduced at 26°C. Unconjugated Gm competitively inhibited uptake of Tr-Gm, demonstrating that this fluorescent compound was taken up similarly to unconjugated Gm. Lysates of F. tularensis bacteria incubated with Gm at 37°C inhibited the growth of Escherichia coli significantly more than lysates from bacteria incubated at 26°C, further indicating reduced uptake at this lower temperature. Other facultative pathogens (Listeria monocytogenes and Klebsiella pneumoniae) exhibited increased resistance to Gm at 26°C suggesting that the results generated using F. tularensis may be generalizable to diverse bacteria. Regulation of the uptake of antibiotics provides a mechanism by which facultative pathogens survive alongside antibiotic-producing microbes in nature. PMID:26858709

Temperature-Dependent Gentamicin Resistance of Francisella tularensis is Mediated by Uptake Modulation.

PubMed

Loughman, Kathleen; Hall, Jesse; Knowlton, Samantha; Sindeldecker, Devin; Gilson, Tricia; Schmitt, Deanna M; Birch, James W-M; Gajtka, Tara; Kobe, Brianna N; Florjanczyk, Aleksandr; Ingram, Jenna; Bakshi, Chandra S; Horzempa, Joseph

2016-01-01

Gentamicin (Gm) is an aminoglycoside commonly used to treat bacterial infections such as tularemia - the disease caused by Francisella tularensis. In addition to being pathogenic, F. tularensis is found in environmental niches such as soil where this bacterium likely encounters Gm producers (Micromonospora sp.). Here we show that F. tularensis exhibits increased resistance to Gm at ambient temperature (26°C) compared to mammalian body temperature (37°C). To evaluate whether F. tularensis was less permeable to Gm at 26°C, a fluorescent marker [Texas Red (Tr)] was conjugated with Gm, yielding Tr-Gm. Bacteria incubated at 26°C showed reduced fluorescence compared to those at 37°C when exposed to Tr-Gm suggesting that uptake of Gm was reduced at 26°C. Unconjugated Gm competitively inhibited uptake of Tr-Gm, demonstrating that this fluorescent compound was taken up similarly to unconjugated Gm. Lysates of F. tularensis bacteria incubated with Gm at 37°C inhibited the growth of Escherichia coli significantly more than lysates from bacteria incubated at 26°C, further indicating reduced uptake at this lower temperature. Other facultative pathogens (Listeria monocytogenes and Klebsiella pneumoniae) exhibited increased resistance to Gm at 26°C suggesting that the results generated using F. tularensis may be generalizable to diverse bacteria. Regulation of the uptake of antibiotics provides a mechanism by which facultative pathogens survive alongside antibiotic-producing microbes in nature.

Dynamics of mono- and dual-species biofilm formation and interactions between Staphylococcus aureus and Gram-negative bacteria.

PubMed

Makovcova, Jitka; Babak, Vladimir; Kulich, Pavel; Masek, Josef; Slany, Michal; Cincarova, Lenka

2017-07-01

Microorganisms are not commonly found in the planktonic state but predominantly form dual- and multispecies biofilms in almost all natural environments. Bacteria in multispecies biofilms cooperate, compete or have neutral interactions according to the involved species. Here, the development of mono- and dual-species biofilms formed by Staphylococcus aureus and other foodborne pathogens such as Salmonella enterica subsp. enterica serovar Enteritidis, potentially pathogenic Raoultella planticola and non-pathogenic Escherichia coli over the course of 24, 48 and 72 h was studied. Biofilm formation was evaluated by the crystal violet assay (CV), enumeration of colony-forming units (CFU cm -2 ) and visualization using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). In general, Gram-negative bacterial species and S. aureus interacted in a competitive manner. The tested Gram-negative bacteria grew better in mixed dual-species biofilms than in their mono-species biofilms as determined using the CV assay, CFU ml -2 enumeration, and CLSM and SEM visualization. In contrast, the growth of S. aureus biofilms was reduced when cultured in dual-species biofilms. CLSM images revealed grape-like clusters of S. aureus and monolayers of Gram-negative bacteria in both mono- and dual-species biofilms. S. aureus clusters in dual-species biofilms were significantly smaller than clusters in S. aureus mono-species biofilms. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Is There Still Room for Novel Viral Pathogens in Pediatric Respiratory Tract Infections?

PubMed Central

Taboada, Blanca; Espinoza, Marco A.; Isa, Pavel; Aponte, Fernando E.; Arias-Ortiz, María A.; Monge-Martínez, Jesús; Rodríguez-Vázquez, Rubén; Díaz-Hernández, Fidel; Zárate-Vidal, Fernando; Wong-Chew, Rosa María; Firo-Reyes, Verónica; del Río-Almendárez, Carlos N.; Gaitán-Meza, Jesús; Villaseñor-Sierra, Alberto; Martínez-Aguilar, Gerardo; Salas-Mier, Ma. del Carmen; Noyola, Daniel E.; Pérez-Gónzalez, Luis F.; López, Susana; Santos-Preciado, José I.; Arias, Carlos F.

2014-01-01

Viruses are the most frequent cause of respiratory disease in children. However, despite the advanced diagnostic methods currently in use, in 20 to 50% of respiratory samples a specific pathogen cannot be detected. In this work, we used a metagenomic approach and deep sequencing to examine respiratory samples from children with lower and upper respiratory tract infections that had been previously found negative for 6 bacteria and 15 respiratory viruses by PCR. Nasal washings from 25 children (out of 250) hospitalized with a diagnosis of pneumonia and nasopharyngeal swabs from 46 outpatient children (out of 526) were studied. DNA reads for at least one virus commonly associated to respiratory infections was found in 20 of 25 hospitalized patients, while reads for pathogenic respiratory bacteria were detected in the remaining 5 children. For outpatients, all the samples were pooled into 25 DNA libraries for sequencing. In this case, in 22 of the 25 sequenced libraries at least one respiratory virus was identified, while in all other, but one, pathogenic bacteria were detected. In both patient groups reads for respiratory syncytial virus, coronavirus-OC43, and rhinovirus were identified. In addition, viruses less frequently associated to respiratory infections were also found. Saffold virus was detected in outpatient but not in hospitalized children. Anellovirus, rotavirus, and astrovirus, as well as several animal and plant viruses were detected in both groups. No novel viruses were identified. Adding up the deep sequencing results to the PCR data, 79.2% of 250 hospitalized and 76.6% of 526 ambulatory patients were positive for viruses, and all other children, but one, had pathogenic respiratory bacteria identified. These results suggest that at least in the type of populations studied and with the sampling methods used the odds of finding novel, clinically relevant viruses, in pediatric respiratory infections are low. PMID:25412469

Prevalence and clinical significance of respiratory viruses and bacteria detected in tuberculosis patients compared to household contact controls in Tanzania: a cohort study.

PubMed

Mhimbira, F; Hiza, H; Mbuba, E; Hella, J; Kamwela, L; Sasamalo, M; Ticlla, M; Said, K; Mhalu, G; Chiryamkubi, M; Schindler, C; Reither, K; Gagneux, S; Fenner, L

2018-03-23

To describe the prevalence of respiratory pathogens in tuberculosis (TB) patients and in their household contact controls, and to determine the clinical significance of respiratory pathogens in TB patients. We studied 489 smear-positive adult TB patients and 305 household contact controls without TB with nasopharyngeal swab samples within an ongoing prospective cohort study in Dar es Salaam, Tanzania, between 2013 and 2015. We used multiplex real-time PCR to detect 16 respiratory viruses and seven bacterial pathogens from nasopharyngeal swabs. The median age of the study participants was 33 years; 61% (484/794) were men, and 21% (168/794) were HIV-positive. TB patients had a higher prevalence of HIV (28.6%; 140/489) than controls (9.2%; 28/305). Overall prevalence of respiratory viral pathogens was 20.4% (160/794; 95%CI 17.7-23.3%) and of bacterial pathogens 38.2% (303/794; 95%CI 34.9-41.6%). TB patients and controls did not differ in the prevalence of respiratory viruses (Odds Ratio [OR] 1.00, 95%CI 0.71-1.44), but respiratory bacteria were less frequently detected in TB patients (OR 0.70, 95%CI 0.53-0.94). TB patients with both respiratory viruses and respiratory bacteria were likely to have more severe disease (adjusted OR [aOR] 1.6, 95%CI 1.1-2.4; p 0.011). TB patients with respiratory viruses tended to have more frequent lung cavitations (aOR 1.6, 95%CI 0.93-2.7; p 0.089). Respiratory viruses are common for both TB patients and household controls. TB patients may present with more severe TB disease, particularly when they are co-infected with both bacteria and viruses. Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Spatial Structure of the Mormon Cricket Gut Microbiome and its Predicted Contribution to Nutrition and Immune Function

PubMed Central

Smith, Chad C.; Srygley, Robert B.; Healy, Frank; Swaminath, Karthikeyan; Mueller, Ulrich G.

2017-01-01

The gut microbiome of insects plays an important role in their ecology and evolution, participating in nutrient acquisition, immunity, and behavior. Microbial community structure within the gut is heavily influenced by differences among gut regions in morphology and physiology, which determine the niches available for microbes to colonize. We present a high-resolution analysis of the structure of the gut microbiome in the Mormon cricket Anabrus simplex, an insect known for its periodic outbreaks in the western United States and nutrition-dependent mating system. The Mormon cricket microbiome was dominated by 11 taxa from the Lactobacillaceae, Enterobacteriaceae, and Streptococcaceae. While most of these were represented in all gut regions, there were marked differences in their relative abundance, with lactic-acid bacteria (Lactobacillaceae) more common in the foregut and midgut and enteric (Enterobacteriaceae) bacteria more common in the hindgut. Differences in community structure were driven by variation in the relative prevalence of three groups: a Lactobacillus in the foregut, Pediococcus lactic-acid bacteria in the midgut, and Pantoea agglomerans, an enteric bacterium, in the hindgut. These taxa have been shown to have beneficial effects on their hosts in insects and other animals by improving nutrition, increasing resistance to pathogens, and modulating social behavior. Using PICRUSt to predict gene content from our 16S rRNA sequences, we found enzymes that participate in carbohydrate metabolism and pathogen defense in other orthopterans. These were predominately represented in the hindgut and midgut, the most important sites for nutrition and pathogen defense. Phylogenetic analysis of 16S rRNA sequences from cultured isolates indicated low levels of divergence from sequences derived from plants and other insects, suggesting that these bacteria are likely to be exchanged between Mormon crickets and the environment. Our study shows strong spatial variation in microbiome community structure, which influences predicted gene content and thus the potential of the microbiome to influence host function. PMID:28553263

Biofilms in drinking water and their role as reservoir for pathogens.

PubMed

Wingender, Jost; Flemming, Hans-Curt

2011-11-01

Most microorganisms on Earth live in various aggregates which are generally termed "biofilms". They are ubiquitous and represent the most successful form of life. They are the active agent in biofiltration and the carriers of the self-cleaning potential in soils, sediments and water. They are also common on surfaces in technical systems where they sometimes cause biofouling. In recent years it has become evident that biofilms in drinking water distribution networks can become transient or long-term habitats for hygienically relevant microorganisms. Important categories of these organisms include faecal indicator bacteria (e.g., Escherichia coli), obligate bacterial pathogens of faecal origin (e.g., Campylobacter spp.) opportunistic bacteria of environmental origin (e.g., Legionella spp., Pseudomonas aeruginosa), enteric viruses (e.g., adenoviruses, rotaviruses, noroviruses) and parasitic protozoa (e.g., Cryptosporidium parvum). These organisms can attach to preexisting biofilms, where they become integrated and survive for days to weeks or even longer, depending on the biology and ecology of the organism and the environmental conditions. There are indications that at least a part of the biofilm populations of pathogenic bacteria persists in a viable but non-culturable (VBNC) state and remains unnoticed by the methods appointed to their detection. Thus, biofilms in drinking water systems can serve as an environmental reservoir for pathogenic microorganisms and represent a potential source of water contamination, resulting in a potential health risk for humans if left unnoticed. Copyright © 2011 Elsevier GmbH. All rights reserved.

Engineered Cationic Antimicrobial Peptides To Overcome Multidrug Resistance by ESKAPE Pathogens

PubMed Central

Deslouches, Berthony; Steckbeck, Jonathan D.; Craigo, Jodi K.; Doi, Yohei; Burns, Jane L.

2014-01-01

Multidrug resistance constitutes a threat to the medical achievements of the last 50 years. In this study, we demonstrated the abilities of two de novo engineered cationic antibiotic peptides (eCAPs), WLBU2 and WR12, to overcome resistance from 142 clinical isolates representing the most common multidrug-resistant (MDR) pathogens and to display a lower propensity to select for resistant bacteria in vitro compared to that with colistin and LL37. The results warrant an exploration of eCAPs for use in clinical settings. PMID:25421473

Threats and opportunities of plant pathogenic bacteria.

PubMed

Tarkowski, Petr; Vereecke, Danny

2014-01-01

Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae. Copyright © 2013 Elsevier Inc. All rights reserved.

Yeast pro- and paraprobiotics have the capability to bind pathogenic bacteria associated with animal disease

USDA-ARS?s Scientific Manuscript database

Live yeast probiotics and yeast cell wall components (paraprobiotics) may serve as an alternative to the use of antibiotics in prevention and treatment of infections caused by pathogenic bacteria. Probiotics and paraprobiotics can bind directly to pathogens, which limits binding of the pathogens to ...

Comparative innate immune interactions of human and bovine secretory IgA with pathogenic and non-pathogenic bacteria.

PubMed

Hodgkinson, Alison J; Cakebread, Julie; Callaghan, Megan; Harris, Paul; Brunt, Rachel; Anderson, Rachel C; Armstrong, Kelly M; Haigh, Brendan

2017-03-01

Secretory IgA (SIgA) from milk contributes to early colonization and maintenance of commensal/symbiotic bacteria in the gut, as well as providing defence against pathogens. SIgA binds bacteria using specific antigenic sites or non-specifically via its glycans attached to α-heavy-chain and secretory component. In our study, we tested the hypothesis that human and bovine SIgA have similar innate-binding activity for bacteria. SIgAs, isolated from human and bovine milk, were incubated with a selection of commensal, pathogenic and probiotic bacteria. Using flow cytometry, we measured numbers of bacteria binding SIgA and their level of SIgA binding. The percentage of bacteria bound by human and bovine SIgA varied from 30 to 90% depending on bacterial species and strains, but was remarkably consistent between human and bovine SIgA. The level of SIgA binding per bacterial cell was lower for those bacteria that had a higher percentage of SIgA-bound bacteria, and higher for those bacteria that had lower percentage of SIgA-bound bacteria. Overall, human and bovine SIgA interacted with bacteria in a comparable way. This contributes to longer term research about the potential benefits of bovine SIgA for human consumers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recurrent urinary tract infections in women: risk factors, etiology, pathogenesis and prophylaxis.

PubMed

Guglietta, Antonio

2017-03-01

Urinary tract infections (UTIs) are one of the most common bacterial infections in women, often as a recurrent disease. Uropathogenic Escherichia coli (UPEC) is the most common pathotype of extraintestinal pathogenic E. coli (ExPEC) found among patients with UTI. The human intestinal can act as a reservoir of UPEC, with the female urethra being infected by fecal material containing UPEC. Adhesion of bacteria to the epithelial cells of urogenital mucosa is an important mechanism in the pathogenesis of UTI. Alternative nonantibiotic based approaches, such as mechanical barrier protection of the intestinal mucosa have been proposed to reduce bacterial adherence to intestinal epithelium, bacteria proliferation and decrease of the load of UPEC in the intestinal lumen and in the fecal material.

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.

Culturable microbiota of ranched southern bluefin tuna (Thunnus maccoyii Castelnau).

PubMed

Valdenegro-Vega, V; Naeem, S; Carson, J; Bowman, J P; Tejedor del Real, J L; Nowak, B

2013-10-01

The Australian tuna industry is based on the ranching of wild southern bluefin tuna (SBT, Thunnus maccoyii). Within this industry, only opportunistic pathogens have been reported infecting external wounds of fish. This study aimed to identify different culturable bacteria present in three cohorts of SBT and to determine normal bacteria and potential pathogens in isolates from harvest fish and moribund/dead fish. Post-mortem changes in the microbiota were also studied. Moribund/dead showed a greater proportion of members from the family Vibrionaceae than harvested fish; the latter presented mainly non-Vibrio species. In harvested fish spleens, Vibrio splendidus I complex was the most commonly identified group among Vibrio isolates, while most groups from the family Vibrionaceae were isolated from gills. For moribund/dead, Vibrio chagasii and Photobacterium damselae subsp. damselae were common in gill, spleen and kidney samples. Non-Vibrio isolates from gills were characterized using 16S rRNA sequencing as Flavobacteriaceae and classes Gammaproteobacteria and Alphaproteobacteria, mainly from the genera Winogradskyella and Tenacibaculum. Post-mortem changes showed dynamic shifts in bacterial dominance in gills, with Vibrionaceae and non-Vibrio spp. found in similar proportions initially and types related to Pseudoalteromonas ruthenica prevailing after 27 h. Spleen samples showed little bacterial growth until 5 h post-mortem, while various Vibrio-associated species were isolated 27 h post-mortem. Bacterial isolates found include a range of potentially pathogenic bacteria that should be monitored though most of them have yet to be associated with disease in tuna. This study forms a foundation for future research into the bacterial population dynamics under different culture conditions of SBT. An understanding of the bacterial compositions in SBT is necessary to evaluate the effects of some bacterial species on their health. © 2013 The Society for Applied Microbiology.

Mycoplasmas and their host: emerging and re-emerging minimal pathogens.

PubMed

Citti, Christine; Blanchard, Alain

2013-04-01

Commonly known as mycoplasmas, bacteria of the class Mollicutes include the smallest and simplest life forms capable of self replication outside of a host. Yet, this minimalism hides major human and animal pathogens whose prevalence and occurrence have long been underestimated. Owing to advances in sequencing methods, large data sets have become available for a number of mycoplasma species and strains, providing new diagnostic approaches, typing strategies, and means for comprehensive studies. A broader picture is thus emerging in which mycoplasmas are successful pathogens having evolved a number of mechanisms and strategies for surviving hostile environments and adapting to new niches or hosts. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bacteria between protists and phages: from antipredation strategies to the evolution of pathogenicity.

PubMed

Brüssow, Harald

2007-08-01

Bacteriophages and protists are major causes of bacterial mortality. Genomics suggests that phages evolved well before eukaryotic protists. Bacteria were thus initially only confronted with phage predators. When protists evolved, bacteria were caught between two types of predators. One successful antigrazing strategy of bacteria was the elaboration of toxins that would kill the grazer. The released cell content would feed bystander bacteria. I suggest here that, to fight grazing protists, bacteria teamed up with those phage predators that concluded at least a temporary truce with them in the form of lysogeny. Lysogeny was perhaps initially a resource management strategy of phages that could not maintain infection chains. Subsequently, lysogeny might have evolved into a bacterium-prophage coalition attacking protists, which became a food source for them. When protists evolved into multicellular animals, the lysogenic bacteria tracked their evolving food source. This hypothesis could explain why a frequent scheme of bacterial pathogenicity is the survival in phagocytes, why a significant fraction of bacterial pathogens have prophage-encoded virulence genes, and why some virulence factors of animal pathogens are active against unicellular eukaryotes. Bacterial pathogenicity might thus be one playing option of the stone-scissor-paper game played between phages-bacteria-protists, with humans getting into the crossfire.

Antibiotic sensitivity pattern of bacteria from diabetic foot infections Haji Adam Malik central general hospital

NASA Astrophysics Data System (ADS)

Bulolo, B. A.; Pase, M. A.; Ginting, F.

2018-03-01

Increasing rate of Diabetic Foot Infections (DFIs) caused by multi-drug-resistance pathogens plays a huge role in the duration of hospitalization, morbidity, and mortality of diabetic patients. The aim of the study is to assess the antibiotic sensitivity pattern of bacteria in DFIs and causative microorganisms. Using cross-sectional retrospective study, data were collected from medical records of DFIs patients previously hospitalized atHaji Adam Malik Hospital, Medan from January to July 2017. 33 patients met the criteria and got enrolled in the study. The classification of DFIs was evaluated according to Wagner’s Classification. Evaluation of antibiotic sensitivity and identification of causative microorganisms were performed in standard microbiologic methods. The most common grade of DFIs was Grade-4 (48.5%), followed by Grade-3 (39.4%) and Grade-5 (9.1%). A total of 12 pathogens were identified. The most common infecting microorganism isolated on pus cultures was Klebsiella pneumonia (33.3%), followed by Escherichia coli (24.2%), Acinetobacter baumanni (12.1%), and Staphylococcus aureus (9.1%). Frequent susceptible antibiotics were Amikacin (88.8%), Imipenem (87%), Meropenem (84.6%), Erythromycin (75%), and Cefoperazone/Sulbactam (68.9%). DFIs are polymicrobial infections in this study K. pneumonia was the most common cause microorganism.

Susceptibility to Lower Respiratory Infections in Childhood is Associated with Perturbation of the Cytokine Response to Pathogenic Airway Bacteria.

PubMed

Vissing, Nadja Hawwa; Larsen, Jeppe Madura; Rasmussen, Morten Arendt; Chawes, Bo Lund Krogsgaard; Thysen, Anna Hammerich; Bønnelykke, Klaus; Brix, Susanne; Bisgaard, Hans

2016-05-01

Neonatal colonization of the airways with respiratory pathogens is associated with increased risk of lower respiratory infections (LRI) in early childhood. Therefore, we hypothesized that children developing LRI have an aberrant immune response to pathogenic bacteria in infancy. The objective was to characterize in vitro the early life systemic immune response to pathogenic bacteria and study the possible association with incidence of LRI during the first 3 years of life. The Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000) is a clinical birth cohort study of 411 children born of mothers with asthma. LRI incidence was prospectively captured from 6-monthly planned visits and visits at acute respiratory episodes. The in vitro systemic immune response to Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae was characterized by the production of TNF-α, IFN-γ, IL-2, IL-5, IL-10, IL-13 and IL-17 in peripheral blood mononuclear cells isolated at age 6 months from 291 infants. Data were analyzed by Poisson regression against incidence of LRI in infancy. A multivariable model including all cytokine responses from the 3 different bacterial stimulations significantly identified children at risk of LRI (P = 0.006). The immune response pattern associated with LRI was characterized by perturbed production of several cytokines rather than production of one specific cytokine, and was independent of concurrent asthma. TNF-α and IL-5 were key drivers but did not explain the entire variation in LRI susceptibility. Children at risk of future LRI present a perturbed systemic immune response upon exposure to common airway pathogens in early life.

Pan-European resistance monitoring programmes encompassing food-borne bacteria and target pathogens of food-producing and companion animals.

PubMed

de Jong, A; Thomas, V; Klein, U; Marion, H; Moyaert, H; Simjee, S; Vallé, M

2013-05-01

Antimicrobial resistance is a concern both for animal and human health. Veterinary programmes monitoring resistance of animal and zoonotic pathogens are therefore essential. Various European countries have implemented national surveillance programmes, particularly for zoonotic and commensal bacteria, and the European Food Safety Authority (EFSA) is compiling the data. However, harmonisation is identified as a weakness and an essential need in order to compare data across countries. Comparisons of resistance monitoring data among national programmes are hampered by differences between programmes, such as sampling and testing methodology, and different epidemiological cut-off values or clinical breakpoints. Moreover, only very few valid data are available regarding target pathogens both of farm and companion animals. The European Animal Health Study Centre (CEESA) attempts to fill these gaps. The resistance monitoring programmes of CEESA have been a collaboration of veterinary pharmaceutical companies for over a decade and include two different projects: the European Antimicrobial Susceptibility Surveillance in Animals (EASSA) programme, which collects food-borne bacteria at slaughter from healthy animals, and the pathogen programmes that collect first-intention target pathogens from acutely diseased animals. The latter comprises three subprogrammes: VetPath; MycoPath; and ComPath. All CEESA projects include uniform sample collection and bacterial identification to species level in various European Union (EU) member states. A central laboratory conducts quantitative susceptibility testing to antimicrobial agents either important in human medicine or commonly used in veterinary medicine. This 'methodology harmonisation' allows easy comparisons among EU member states and makes the CEESA programmes invaluable to address food safety and antibiotic efficacy. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Size-dependent antibacterial activities of silver nanoparticles against oral anaerobic pathogenic bacteria.

PubMed

Lu, Zhong; Rong, Kaifeng; Li, Ju; Yang, Hao; Chen, Rong

2013-06-01

Dental caries and periodontal disease are widespread diseases for which microorganism infections have been identified as the main etiology. Silver nanoparticles (Ag Nps) were considered as potential control oral bacteria infection agent due to its excellent antimicrobial activity and non acute toxic effects on human cells. In this work, stable Ag Nps with different sizes (~5, 15 and 55 nm mean values) were synthesized by using a simple reduction method or hydrothermal method. The Nps were characterized by powder X-ray diffraction, transmission electron microscopy and UV-vis absorption spectroscopy. The antibacterial activities were evaluated by colony counting assay and growth inhibition curve method, and corresponding minimum inhibitory concentration (MIC) against five anaerobic oral pathogenic bacteria and aerobic bacteria E. coli were determined. The results showed that Ag Nps had apparent antibacterial effects against the anaerobic oral pathogenic bacteria and aerobic bacteria. The MIC values of 5-nm Ag against anaerobic oral pathogenic bacteria A. actinomycetemcomitans, F. nuceatum, S. mitis, S. mutans and S. sanguis were 25, 25, 25, 50 and 50 μg/mL, respectively. The aerobic bacteria were more susceptible to Ag NPs than the anaerobic oral pathogenic bacteria. In the mean time, Ag NPs displayed an obvious size-dependent antibacterial activity against the anaerobic bacteria. The 5-nm Ag presents the highest antibacterial activity. The results of this work indicated a potential application of Ag Nps in the inhibition of oral microorganism infections.

Economic assessment and pathogenic bacteria inhibition of bovine hide presoaking solutions formulated with enzymes that can remove adobe-type manure

USDA-ARS?s Scientific Manuscript database

The presoaking formulations that have recently been developed are effective in removing the damaging adobe type bovine manure and eco-friendly because the ingredients used are recycled and required only a quarter of the amount of biocide and surfactant that the industry is commonly using. The goal ...

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

USGS Publications Warehouse

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

2005-01-01

A preliminary study was done in Oakland County, Michigan, to determine the concentration of fecal indicator bacteria (fecal coliform bacteria and enterococci), antibiotic resistance patterns of these two groups, and the presence of potentially pathogenic Escherichia coli (E. coli). For selected sites, specific members of these groups [E. coli, Enterococcus faecium (E. faecium) and Enterococcus faecalis (E. faecalis)] were isolated and tested for levels of resistance to specific antibiotics used to treat human infections by pathogens in these groups and for their potential to transfer these resistances. In addition, water samples from all sites were tested for indicators of potentially pathogenic E. coli by three assays: a growth-based assay for sorbitol-negative E. coli, an immunological assay for E. coli O157, and a molecular assay for three virulence and two serotype genes. Samples were also collected from two non-urbanized sites outside of Oakland County. Results from the urbanized Oakland County area were compared to those from these two non-urbanized sites. Fecal indicator bacteria concentrations exceeded State of Michigan recreational water-quality standards and (or) recommended U.S. Environmental Protection Agency (USEPA) standards in samples from all but two Oakland County sites. Multiple-antibiotic-resistant fecal coliform bacteria were found at all sites, including two reference sites from outside the county. Two sites (Stony Creek and Paint Creek) yielded fecal coliform isolates resistant to all tested antibiotics. Patterns indicative of extended-spectrum-β-lactamase (ESBL)- producing fecal coliform bacteria were found at eight sites in Oakland County and E. coli resistant to clinically significant antibiotics were recovered from the River Rouge, Clinton River, and Paint Creek. Vancomycin-resistant presumptive enterococci were found at six sites in Oakland County and were not found at the reference sites. Evidence of acquired antibiotic resistances was detected in bacteria from multiple sites in Oakland County but not detected in bacteria from the reference sites. Integrons capable of transferring resistance were detected in isolates from the River Rouge and Clinton River. E. faecium and E. faecalis identified in samples collected from Kearsley Creek and Evans Ditch were resistant to high levels of vancomycin and carried transferable genes responsible for resistance. Several sites in Oakland County had indicators of pathogenic E. coli in August and (or) September 2003. Two samples from the Clinton River in August tested positive for all three E. coli O157 tests. Both the August and September samples from one River Rouge site were positive for the immunological and molecular assay for E. coli O157. A combination of virulence genes commonly associated with human illness was detected at five sites in August and seven sites in September. Antibiotic-resistance profiles of clinical concern along with genes capable of transferring the resistance were found at several sites throughout Oakland County; samples from many of these sites also contained potentially pathogenic E. coli.

An antibacterial vaccination strategy based on a glycoconjugate containing the core lipopolysaccharide tetrasaccharide Hep2Kdo2

NASA Astrophysics Data System (ADS)

Kong, Lingbing; Vijayakrishnan, Balakumar; Kowarik, Michael; Park, Jin; Zakharova, Alexandra N.; Neiwert, Larissa; Faridmoayer, Amirreza; Davis, Benjamin G.

2016-03-01

Certain non-mammalian cell wall sugars are conserved across a variety of pathogenic bacteria. This conservation of structure, combined with their structural differences when compared with mammalian sugars, make them potentially powerful epitopes for immunization. Here, we report the synthesis of a glycoconjugate that displays the so-called ‘inner core’ sugars of Gram-negative bacterial cell walls. We also describe an antibacterial vaccination strategy based on immunization with the glycoconjugate and the subsequent administration of an inhibitor that uncovers the corresponding epitope in pathogenic bacteria. The core tetrasaccharide, Hep2Kdo2, a common motif in bacterial lipopolysaccharides, was synthesized and attached via a chain linker to a diphtheria toxin mutant carrier protein. This glycoconjugate generated titres of antibodies towards the inner core tetrasaccharide of the lipopolysaccharide, which were capable of binding the cell-surface sugars of bacterial pathogenic strains including Neisseria meningitidis, Pseudomonas aeruginosa and Escherichia coli. Exposure of bacterial lipopolysaccharide in in vitro experiments, using an inhibitor of capsular polysaccharide transport, enabled potent bacterial killing with antiserum.

What is the true clinical relevance of Simkania negevensis and other emerging Chlamydiales members?

PubMed

Vouga, M; Kebbi-Beghdadi, C; Liénard, J; Baskin, L; Baud, D; Greub, G

2018-05-01

Waddlia   chondrophila and Simkania negevensis are emerging Chlamydia- related bacteria. Similar to the pathogenic organisms Chlamydia pneumoniae and Chlamydia trachomatis, these emerging bacteria are implicated in human genital infections and respiratory diseases. We used a screening strategy based on a newly developed S. negevensis -specific quantitative real-time PCR (qPCR) and a pan- Chlamydiales qPCR. We could not detect S. negevensis in 458 respiratory, genitourinary, cardiac and hepatic samples tested. One urethral swab was positive for W. chondrophila. We observed a low prevalence of Chlamydiales in respiratory samples (1/200, 0.5%), which suggests that C. pneumoniae is an uncommon respiratory pathogen. Furthermore, we screened 414 human serum samples from Switzerland, England and Israel and observed a low prevalence (<1%) of exposure to S. negevensis. Conversely, humans were commonly exposed to W. chondrophila, with seroprevalences ranging from 8.6% to 32.5%. S. negevensis is not a clinically relevant pathogen, but further research investigating the role of W. chondrophila is needed.

Decreased waterborne pathogenic bacteria in an urban aquifer related to intense shallow geothermal exploitation.

PubMed

García-Gil, Alejandro; Gasco-Cavero, Samanta; Garrido, Eduardo; Mejías, Miguel; Epting, Jannis; Navarro-Elipe, Mercedes; Alejandre, Carmen; Sevilla-Alcaine, Elena

2018-08-15

The implications of intensive use of shallow geothermal energy resources in shallow urban aquifers are still not known for waterborne pathogens relevant to human health. Firstly, we hypothesized that waterborne enteric pathogens would be relatively increased in heated groundwater plumes. To prove this, microbiological sampling of 31 piezometers covering the domain of an urban groundwater body affected by microbiological contamination and energetically exploited by 70 groundwater heat pump systems was performed. Mean differences of pathogenic bacteria contents between impacted and non-impacted monitoring points were assessed with a two-tailed independent Student's t-test or Mann-Whitney U and correlation coefficients were also calculated. Surprisingly, the results obtained revealed a significant and generalized decrease in waterborne pathogen contents in thermally impacted piezometers compared to that of non-impacted piezometers. This decrease is hypothesized to be caused by a heat shock to bacteria within the heat exchangers. The statistically significant negative correlations obtained between waterborne pathogen counts and temperature could be explained by the spatial distribution of the bacteria, finding that bacteria start to recover with increasing distance from the injection point. Also, different behavior groups fitting exponential regression models were found for the bacteria species studied, justified by the different presence and influence of several aquifer parameters and major, minor and trace elements studied, as well as the coexistence with other bacteria species. The results obtained from this work reinforce the concept of shallow geothermal resources as a clean energy source, as they could also provide the basis to control the pathogenic bacteria contents in groundwater bodies. Copyright © 2018 Elsevier B.V. All rights reserved.

Frequency and antimicrobial susceptibility of gram-negative bacteria isolated from 2 hospitals in Makkah, Saudi Arabia.

PubMed

Asghar, Atif H; Faidah, Hani S

2009-08-01

To estimate the prevalence and antibiotic susceptibility of the gram-negative bacteria isolated from 2 hospitals in Makkah. This study was undertaken in 2 main tertiary care hospitals namely; Al-Noor Specialist Hospital, and Hera Hospital in Makkah, Kingdom of Saudi Arabia from October 2005 to March 2006. A total of 1137 gram-negative bacteria were identified in non-duplicate clinical specimens obtained from 965 patients of various body sites infections. Demographic data, identity of microorganisms, and antimicrobial susceptibilities were obtained from medical and laboratory records. The most prevalent gram-negative bacteria were Escherichia coli (31.6%), and Pseudomonas aeruginosa (31.2%), followed by Acinetobacter baumannii (10.8%), Klebsiella pneumoniae (8.3%), Klebsiella sp. (6.2%), Haemophilus influenzae (3.7%), Proteus sp. (3.3%), and Enterobacter sp. (1.9%). Results demonstrated that gram-negative bacteria have a high rate of resistance to commonly used antibiotics. Furthermore, multi-drug resistance was also common in this study. Our data showed a high rate of resistance among gram-negative pathogens in comparison with other countries in the world. The implementation of monitoring programs is an important part of the prevention strategy against the development of antibiotic resistance in hospitals.

Metaproteomics reveals abundant transposase expression in mutualistic endosymbionts

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

Kleiner, Manuel; Young, Jacque C; Shah, Manesh B

2013-01-01

Transposases, enzymes that catalyze the movement of mobile genetic elements, are the most abundant genes in nature. While many bacteria encode an abundance of transposases in their genomes, the current paradigm is that transposase gene expression is tightly regulated and generally low due to its severe mutagenic effects. In the current study, we detected the highest number of transposase proteins ever reported in bacteria, in symbionts of the gutless marine worm Olavius algarvensis using metaproteomics. At least 26 different transposases from 12 different families were detected and genomic and proteomic analyses suggest many of these are active. This high expressionmore » of transposases indicates that the mechanisms for their tight regulation have been disabled or destroyed. Based on recent studies on other symbionts and pathogens that showed high transposase transcription, we speculate that abundant transposase expression might be common in symbionts and pathogens.« less

LOW PATHOGENIC POTENTIAL IN HETEROTROPHIC BACTERIA FROM POTABLE WATER

EPA Science Inventory

Forty-five isolates of HPC bacteria, most of which express virulence-related characteristics are being tested for pathogenicity in immunocompromised mice. All forty-five were negative for facultative intracellular pathogenicity. All twenty-three isolates tested thus far were a...

Mucosal immunity to pathogenic intestinal bacteria.

PubMed

Perez-Lopez, Araceli; Behnsen, Judith; Nuccio, Sean-Paul; Raffatellu, Manuela

2016-03-01

The intestinal mucosa is a particularly dynamic environment in which the host constantly interacts with trillions of commensal microorganisms, known as the microbiota, and periodically interacts with pathogens of diverse nature. In this Review, we discuss how mucosal immunity is controlled in response to enteric bacterial pathogens, with a focus on the species that cause morbidity and mortality in humans. We explain how the microbiota can shape the immune response to pathogenic bacteria, and we detail innate and adaptive immune mechanisms that drive protective immunity against these pathogens. The vast diversity of the microbiota, pathogens and immune responses encountered in the intestines precludes discussion of all of the relevant players in this Review. Instead, we aim to provide a representative overview of how the intestinal immune system responds to pathogenic bacteria.

Infection processes of xylem-colonizing pathogenic bacteria: possible explanations for the scarcity of qualitative disease resistance genes against them in crops.

PubMed

Bae, Chungyun; Han, Sang Wook; Song, Yu-Rim; Kim, Bo-Young; Lee, Hyung-Jin; Lee, Je-Min; Yeam, Inhwa; Heu, Sunggi; Oh, Chang-Sik

2015-07-01

Disease resistance against xylem-colonizing pathogenic bacteria in crops. Plant pathogenic bacteria cause destructive diseases in many commercially important crops. Among these bacteria, eight pathogens, Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, Erwinia amylovora, Pantoea stewartii subsp. stewartii, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. actinidiae, and Xylella fastidiosa, infect their host plants through different infection sites and paths and eventually colonize the xylem tissues of their host plants, resulting in wilting symptoms by blocking water flow or necrosis of xylem tissues. Noticeably, only a relatively small number of resistant cultivars in major crops against these vascular bacterial pathogens except X. oryzae pv. oryzae have been found or generated so far, although these pathogens threaten productivity of major crops. In this review, we summarize the lifestyles of major xylem-colonizing bacterial pathogens and then discuss the progress of current research on disease resistance controlled by qualitative disease resistance genes or quantitative trait loci against them. Finally, we propose infection processes of xylem-colonizing bacterial pathogens as one of possible reasons for why so few qualitative disease resistance genes against these pathogens have been developed or identified so far in crops.

A distributed national network for label-free rapid identification of emerging pathogens

NASA Astrophysics Data System (ADS)

Robinson, J. Paul; Rajwa, Bartek P.; Dundar, M. Murat; Bae, Euiwon; Patsekin, Valery; Hirleman, E. Daniel; Roumani, Ali; Bhunia, Arun K.; Dietz, J. Eric; Davisson, V. Jo; Thomas, John G.

2011-05-01

Typical bioterrorism prevention scenarios assume well-known and well-characterized pathogens like anthrax or tularemia, which are serious public concerns if released into food and/or water supplies or distributed using other vectors. Common governmental contingencies include rapid response to these biological threats with predefined treatments and management operations. However, bioterrorist attacks may follow a far more sophisticated route. With the widely known and immense progress in genetics and the availability of molecular biology tools worldwide, the potential for malicious modification of pathogenic genomes is very high. Common non-pathogenic microorganisms could be transformed into dangerous, debilitating pathogens. Known pathogens could also be modified to avoid detection, because organisms are traditionally identified on the basis of their known physiological or genetic properties. In the absence of defined primers a laboratory using genetic biodetection methods such as PCR might be unable to quickly identify a modified microorganism. Our concept includes developing a nationwide database of signatures based on biophysical (such as elastic light scattering (ELS) properties and/or Raman spectra) rather than genetic properties of bacteria. When paired with a machine-learning system for emerging pathogen detection these data become an effective detection system. The approach emphasizes ease of implementation using a standardized collection of phenotypic information and extraction of biophysical features of pathogens. Owing to the label-free nature of the detection modalities ELS is significantly less costly than any genotypic or mass spectrometry approach.

Pathogenic bacteria in sewage treatment plants as revealed by 454 pyrosequencing.

PubMed

Ye, Lin; Zhang, Tong

2011-09-01

This study applied 454 high-throughput pyrosequencing to analyze potentially pathogenic bacteria in activated sludge from 14 municipal wastewater treatment plants (WWTPs) across four countries (China, U.S., Canada, and Singapore), plus the influent and effluent of one of the 14 WWTPs. A total of 370,870 16S rRNA gene sequences with average length of 207 bps were obtained and all of them were assigned to corresponding taxonomic ranks by using RDP classifier and MEGAN. It was found that the most abundant potentially pathogenic bacteria in the WWTPs were affiliated with the genera of Aeromonas and Clostridium. Aeromonas veronii, Aeromonas hydrophila, and Clostridium perfringens were species most similar to the potentially pathogenic bacteria found in this study. Some sequences highly similar (>99%) to Corynebacterium diphtheriae were found in the influent and activated sludge samples from a saline WWTP. Overall, the percentage of the sequences closely related (>99%) to known pathogenic bacteria sequences was about 0.16% of the total sequences. Additionally, a platform-independent Java application (BAND) was developed for graphical visualization of the data of microbial abundance generated by high-throughput pyrosequencing. The approach demonstrated in this study could examine most of the potentially pathogenic bacteria simultaneously instead of one-by-one detection by other methods.

Isolation and identification of bacterial pathogen from mastitis milk in Central Java Indonesia

NASA Astrophysics Data System (ADS)

Harjanti, D. W.; Ciptaningtyas, R.; Wahyono, F.; Setiatin, ET

2018-01-01

Mastitis is a multi-etiologic disease of the mammary gland characterized mainly by reduction in milk production and milk quality due to intramammary infection by pathogenic bacteria. Nearly 83% of lactating dairy cows in Indonesia are infected with mastitis in various inflammation degrees. This study was conducted to isolate and identify the pathogen in milk collected from mastitis-infected dairy cows. The study was carried out in ten smallholder dairy farms in Central Java Indonesia based on animal examination, California mastitis test, isolation bacterial pathogens, Gram staining, Catalase and Coagulase test, and identification of bacteria species using Vitek. Bacteriological examination of milk samples revealed 15 isolates where Streptococcus was predominant species (73.3%) and the coagulase negative Staphylococcus species was identified at the least bacteria (26.7%). The Streptococcus bacteria found were Streptococcus uberis (2 isolates), Streptococcus sanguinis(6 isolates), Streptococcus dysgalactiaessp dysgalactiae(1 isolate) , Streptococcus mitis (1 isolate) and Streptococcus agalactiae (1 isolate). The Staphylococcus isolates comprising of Staphylococcus simulans (1 isolate) and Staphylococcus chromogens (3 isolates). Contamination of raw milkwith pathogenic bacteria can cause outbreaks of human disease (milk borne disease). Thus, proper milk processing method that couldinhibit the growth or kill these pathogenic bacteria is important to ensure the safety of milk and milk products.

Raft-like membrane domains in pathogenic microorganisms.

PubMed

Farnoud, Amir M; Toledo, Alvaro M; Konopka, James B; Del Poeta, Maurizio; London, Erwin

2015-01-01

The lipid bilayer of the plasma membrane is thought to be compartmentalized by the presence of lipid-protein microdomains. In eukaryotic cells, microdomains composed of sterols and sphingolipids, commonly known as lipid rafts, are believed to exist, and reports on the presence of sterol- or protein-mediated microdomains in bacterial cell membranes are also appearing. Despite increasing attention, little is known about microdomains in the plasma membrane of pathogenic microorganisms. This review attempts to provide an overview of the current state of knowledge of lipid rafts in pathogenic fungi and bacteria. The current literature on characterization of microdomains in pathogens is reviewed, and their potential role in growth, pathogenesis, and drug resistance is discussed. Better insight into the structure and function of membrane microdomains in pathogenic microorganisms might lead to a better understanding of their pathogenesis and development of raft-mediated approaches for therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

Pathogens and host immunity in the ancient human oral cavity

PubMed Central

Warinner, Christina; Matias Rodrigues, João F.; Vyas, Rounak; Trachsel, Christian; Shved, Natallia; Grossmann, Jonas; Radini, Anita; Hancock, Y.; Tito, Raul Y.; Fiddyment, Sarah; Speller, Camilla; Hendy, Jessica; Charlton, Sophy; Luder, Hans Ulrich; Salazar-García, Domingo C.; Eppler, Elisabeth; Seiler, Roger; Hansen, Lars; Samaniego Castruita, José Alfredo; Barkow-Oesterreicher, Simon; Teoh, Kai Yik; Kelstrup, Christian; Olsen, Jesper V.; Nanni, Paolo; Kawai, Toshihisa; Willerslev, Eske; von Mering, Christian; Lewis, Cecil M.; Collins, Matthew J.; Gilbert, M. Thomas P.; Rühli, Frank; Cappellini, Enrico

2014-01-01

Calcified dental plaque (dental calculus) preserves for millennia and entraps biomolecules from all domains of life and viruses. We report the first high-resolution taxonomic and protein functional characterization of the ancient oral microbiome and demonstrate that the oral cavity has long served as a reservoir for bacteria implicated in both local and systemic disease. We characterize: (i) the ancient oral microbiome in a diseased state, (ii) 40 opportunistic pathogens, (iii) the first evidence of ancient human-associated putative antibiotic resistance genes, (iv) a genome reconstruction of the periodontal pathogen Tannerella forsythia, (v) 239 bacterial and 43 human proteins, allowing confirmation of a long-term association between host immune factors, “red-complex” pathogens, and periodontal disease, and (vi) DNA sequences matching dietary sources. Directly datable and nearly ubiquitous, dental calculus permits the simultaneous investigation of pathogen activity, host immunity, and diet, thereby extending the direct investigation of common diseases into the human evolutionary past. PMID:24562188

List of new names of plant pathogenic bacteria (2011-2012)

USDA-ARS?s Scientific Manuscript database

The International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria has responsibility to evaluate the names of newly proposed pathovars for adherence to the International Standards for Naming Pathovars of Phytopathogenic Bacteria. Currently, the Comprehensive List of...

The Effectiveness of Heterotrophic Bacteria Isolated from Dumai Marine Waters of Riau, Used as Antibacterial against Pathogens in Fish Culture

NASA Astrophysics Data System (ADS)

Feliatra, F.; Nursyirwani; Tanjung, A.; Adithiya, DS; Susanna, M.; Lukystyowati, I.

2018-02-01

Heterotrophic bacteria have an important role as decomposer of organic compounds (mineralization) derived from industrial waste, decomposition of unconsumed feed, faecal, excretion of fish, and have the ability to inhibit the growth of pathogenic bacteria. We investigated the role of heterotrophic bacteria used as antibacterial against pathogens in fish culture.This research was conducted from January until March 2017. The phylogenitic of the isolated bacterial was determined by 16S rDNA sequences analysis. Antagonism test showed that the bacteria had the ability to inhibit the growth of pathogenic bacteria (Vibrio alginolyticus, Aeromonas hydrophila and Pseudomonas sp.) Three isolates (Dm5, Dm6 and Dm4) indicated high inhibition zones which were classified into strong category with the average from 10.5 to 11.8 mm toward V. alginolitycus. Other isolates were classified into medium and weak category. Based on DNA analysis of heterotrophic bacteria isolated from marine waters of industrial area and low salinity of estuarine waters twelve strains of bacteria were identified, and all had highest level of homology to Bacillus sp.,one isolates has similarity to Enterobacter cloacae, other isolates to Clostridium cetobutylicum. Most of isolated bacteria obtained from the waters of industrial area due to it received much of nutrients that very influenced the growth of bacteria.

Characterization of Bacteria Associated with Pinewood Nematode Bursaphelenchus xylophilus

PubMed Central

Vicente, Claudia S. L.; Nascimento, Francisco; Espada, Margarida; Barbosa, Pedro; Mota, Manuel; Glick, Bernard R.; Oliveira, Solange

2012-01-01

Pine wilt disease (PWD) is a complex disease integrating three major agents: the pathogenic agent, the pinewood nematode Bursaphelenchus xylophilus; the insect-vector Monochamus spp.; and the host pine tree, Pinus sp. Since the early 80's, the notion that another pathogenic agent, namely bacteria, may play a role in PWD has been gaining traction, however the role of bacteria in PWD is still unknown. The present work supports the possibility that some B. xylophilus-associated bacteria may play a significant role in the development of this disease. This is inferred as a consequence of: (i) the phenotypic characterization of a collection of 35 isolates of B. xylophilus-associated bacteria, in different tests broadly used to test plant pathogenic and plant growth promoting bacteria, and (ii) greenhouse experiments that infer the pathogenicity of these bacteria in maritime pine, Pinus pinaster. The results illustrate the presence of a heterogeneous microbial community associated with B. xylophilus and the traits exhibited by at least, some of these bacteria, appear to be related to PWD symptoms. The inoculation of four specific B. xylophilus-associated bacteria isolates in P. pinaster seedlings resulted in the development of some PWD symptoms suggesting that these bacteria likely play an active role with B. xylophilus in PWD. PMID:23091599

Quantitative Real-time Polymerase Chain Reaction for Enteropathogenic Escherichia coli: A Tool for Investigation of Asymptomatic Versus Symptomatic Infections

PubMed Central

Barletta, Francesca; Mercado, Erik; Ruiz, Joaquim; Ecker, Lucie; Lopez, Giovanni; Mispireta, Monica; Gil, Ana I.; Lanata, Claudio F.; Cleary, Thomas G.

2011-01-01

Background. Enteropathogenic Escherichia coli (EPEC) strains are pediatric pathogens commonly isolated from both healthy and sick children with diarrhea in areas of endemicity. The aim of this study was to compare the bacterial load of EPEC isolated from stool samples from children with and without diarrhea to determine whether bacterial load might be a useful tool for further study of this phenomenon. Methods. EPEC was detected by polymerase chain reaction (PCR) of colonies isolated on MacConkey plates from 53 diarrheal and 90 healthy children aged <2 years. DNA was isolated from stool samples by cetyltrimethylammonium bromide extraction. To standardize quantification by quantitative real-time PCR (qRT-PCR), the correlation between fluorescence threshold cycle and copy number of the intimin gene of EPEC E2348/69 was determined. Results. The detection limit of qRT-PCR was 5 bacteria/mg stool. The geometric mean load in diarrhea was 299 bacteria/mg (95% confidence interval [CI], 77–1164 bacteria/mg), compared with 29 bacteria/mg (95% CI, 10–87 bacteria/mg) in control subjects (P = .016). Bacterial load was significantly higher in children with diarrhea than in control subjects among children <12 months of age (178 vs 5 bacteria/mg; P = .006) and among children with EPEC as the sole pathogen (463 vs 24 bacteria/mg; P = .006). Conclusions. EPEC load measured by qRT-PCR is higher in diarrheal than in healthy children. qRT-PCR may be useful to study the relationship between disease and colonization in settings of endemicity. PMID:22028433

Attachment of 13 Types of Foodborne Bacteria to Jalapeño and Serrano Peppers and Antibacterial Effect of Roselle Calyx Extracts, Sodium Hypochlorite, Colloidal Silver, and Acetic Acid against These Foodborne Bacteria on Peppers.

PubMed

Rangel-Vargas, Esmeralda; Gómez-Aldapa, Carlos A; Falfan-Cortes, Reyna N; Rodríguez-Marín, María L; Godínez-Oviedo, Angélica; Acevedo-Sandoval, Otilio A; Castro-Rosas, Javier

2017-03-01

Chili peppers are a very important crop in Mexico. However, these peppers have been associated with Salmonella infection outbreaks in the United States, and Salmonella and diarrheagenic Escherichia coli pathotypes have been isolated from jalapeño and serrano peppers in Mexico. To decrease microbial contamination of fruits and vegetables, chemical agents are commonly used; however, chemical agents used to eliminate pathogenic bacteria on vegetables have a limited antimicrobial effect. Roselle ( Hibiscus sabdariffa ) calyces have been reported to have an antimicrobial effect on pathogenic bacteria. In the present study, the antibacterial effect of four roselle calyx extracts (water, methanol, acetone, and ethyl acetate), sodium hypochlorite, colloidal silver, and acetic acid against foodborne bacteria was evaluated on contaminated jalapeño and serrano peppers. The 13 types of foodborne bacteria evaluated were Listeria monocytogenes , Shigella flexneri , Salmonella Typhimurium, Salmonella Typhi, Salmonella Montevideo, Staphylococcus aureus , E. coli O157:H7, five E. coli pathotypes (Shiga toxin producing, enteropathogenic, enterotoxigenic, enteroinvasive, and enteroaggregative), and Vibrio cholerae O1. All 13 types attached to both pepper types, with no significant differences in attachment between jalapeño and serrano peppers. Roselle calyx extract treatment resulted in a greater reduction in levels of all foodborne bacteria than did treatment with sodium hypochlorite, colloidal silver, and acetic acid on both pepper types. Roselle calyx extracts may be a useful for disinfection of chili peppers in the field, processing plants, restaurants, and homes.

RARE OCCURRENCE OF HETEROTROPHIC BACTERIA WITH PATHOGENIC POTENTIAL IN POTABLE WATER

EPA Science Inventory

Since the discovery of Legionella pneumophila, an opportunistic pathogen that is indigenous to water, microbiologists have speculated that there may be other opportunistic pathogens among the numerous heterotrophic bacteria found in potable water. The USEPA developed a series of...

Comparative Pathogenomics Reveals Horizontally Acquired Novel Virulence Genes in Fungi Infecting Cereal Hosts

PubMed Central

Gardiner, Donald M.; McDonald, Megan C.; Covarelli, Lorenzo; Solomon, Peter S.; Rusu, Anca G.; Marshall, Mhairi; Kazan, Kemal; Chakraborty, Sukumar; McDonald, Bruce A.; Manners, John M.

2012-01-01

Comparative analyses of pathogen genomes provide new insights into how pathogens have evolved common and divergent virulence strategies to invade related plant species. Fusarium crown and root rots are important diseases of wheat and barley world-wide. In Australia, these diseases are primarily caused by the fungal pathogen Fusarium pseudograminearum. Comparative genomic analyses showed that the F. pseudograminearum genome encodes proteins that are present in other fungal pathogens of cereals but absent in non-cereal pathogens. In some cases, these cereal pathogen specific genes were also found in bacteria associated with plants. Phylogenetic analysis of selected F. pseudograminearum genes supported the hypothesis of horizontal gene transfer into diverse cereal pathogens. Two horizontally acquired genes with no previously known role in fungal pathogenesis were studied functionally via gene knockout methods and shown to significantly affect virulence of F. pseudograminearum on the cereal hosts wheat and barley. Our results indicate using comparative genomics to identify genes specific to pathogens of related hosts reveals novel virulence genes and illustrates the importance of horizontal gene transfer in the evolution of plant infecting fungal pathogens. PMID:23028337

Regulatory principles governing Salmonella and Yersinia virulence

PubMed Central

Erhardt, Marc; Dersch, Petra

2015-01-01

Enteric pathogens such as Salmonella and Yersinia evolved numerous strategies to survive and proliferate in different environmental reservoirs and mammalian hosts. Deciphering common and pathogen-specific principles for how these bacteria adjust and coordinate spatiotemporal expression of virulence determinants, stress adaptation, and metabolic functions is fundamental to understand microbial pathogenesis. In order to manage sudden environmental changes, attacks by the host immune systems and microbial competition, the pathogens employ a plethora of transcriptional and post-transcriptional control elements, including transcription factors, sensory and regulatory RNAs, RNAses, and proteases, to fine-tune and control complex gene regulatory networks. Many of the contributing global regulators and the molecular mechanisms of regulation are frequently conserved between Yersinia and Salmonella. However, the interplay, arrangement, and composition of the control elements vary between these closely related enteric pathogens, which generate phenotypic differences leading to distinct pathogenic properties. In this overview we present common and different regulatory networks used by Salmonella and Yersinia to coordinate the expression of crucial motility, cell adhesion and invasion determinants, immune defense strategies, and metabolic adaptation processes. We highlight evolutionary changes of the gene regulatory circuits that result in different properties of the regulatory elements and how this influences the overall outcome of the infection process. PMID:26441883

Next-generation sequencing identification of pathogenic bacterial genes and their relationship with fecal indicator bacteria in different water sources in the Kathmandu Valley, Nepal.

PubMed

Ghaju Shrestha, Rajani; Tanaka, Yasuhiro; Malla, Bikash; Bhandari, Dinesh; Tandukar, Sarmila; Inoue, Daisuke; Sei, Kazunari; Sherchand, Jeevan B; Haramoto, Eiji

2017-12-01

Bacteriological analysis of drinking water leads to detection of only conventional fecal indicator bacteria. This study aimed to explore and characterize bacterial diversity, to understand the extent of pathogenic bacterial contamination, and to examine the relationship between pathogenic bacteria and fecal indicator bacteria in different water sources in the Kathmandu Valley, Nepal. Sixteen water samples were collected from shallow dug wells (n=12), a deep tube well (n=1), a spring (n=1), and rivers (n=2) in September 2014 for 16S rRNA gene next-generation sequencing. A total of 525 genera were identified, of which 81 genera were classified as possible pathogenic bacteria. Acinetobacter, Arcobacter, and Clostridium were detected with a relatively higher abundance (>0.1% of total bacterial genes) in 16, 13, and 5 of the 16 samples, respectively, and the highest abundance ratio of Acinetobacter (85.14%) was obtained in the deep tube well sample. Furthermore, the bla OXA23-like genes of Acinetobacter were detected using SYBR Green-based quantitative PCR in 13 (35%) of 37 water samples, including the 16 samples that were analyzed for next-generation sequencing, with concentrations ranging 5.3-7.5logcopies/100mL. There was no sufficient correlation found between fecal indicator bacteria, such as Escherichia coli and total coliforms, and potential pathogenic bacteria, as well as the bla OXA23-like gene of Acinetobacter. These results suggest the limitation of using conventional fecal indicator bacteria in evaluating the pathogenic bacteria contamination of different water sources in the Kathmandu Valley. Copyright © 2017 Elsevier B.V. All rights reserved.

Association of plasma 25-hydroxyvitamin d concentrations and pathogenic oral bacteria in postmenopausal females.

PubMed

Sahli, Michelle W; Wactawski-Wende, Jean; Ram, Pavani K; LaMonte, Michael J; Hovey, Kathleen M; Genco, Robert J; Andrews, Christopher A; Millen, Amy E

2014-07-01

Previous findings of an association between 25-hydroxyvitamin D [25(OH)D] concentrations and periodontal disease may be partially explained by the antimicrobial properties of vitamin D. To the best of the authors' knowledge, no study has investigated the association between 25(OH)D and pathogenic oral bacteria, a putative cause of periodontal disease. The association between plasma 25(OH)D concentrations and pathogenic oral bacteria was examined among postmenopausal females in the Buffalo Osteoporosis and Periodontal Disease Study (1997 to 2000), an ancillary study of the Women's Health Initiative Observational Study. Subgingival plaque samples were assessed using immunofluorescence for the presence of Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Prevotella intermedia, and Campylobacter rectus. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for prevalent bacteria by quintile (Q) of 25(OH)D concentrations, adjusting for age and body mass index. Of the 855 participants, 288 (34%) had deficient/inadequate (<50 nmol/L) 25(OH)D concentrations, and 496 (58%) had at least one species of pathogenic bacteria. No significant association was found between 25(OH)D and presence of any of these bacteria (adjusted OR for high [Q5] compared to low [Q1] 25(OH)D = 0.96; 95% CI: 0.61 to 1.50; P for trend = 0.50). Inverse, although not statistically significant, associations were found between 25(OH)D and more than one species of pathogenic bacteria (adjusted OR for adequate compared to deficient/inadequate 25(OH)D = 0.85; 95% CI: 0.60 to 1.19). No association was observed between pathogenic oral bacteria and 25(OH)D concentrations in postmenopausal females. This may be attributable to the species of bacteria assessed, small effect size, or a true absence of an association.

Selection of bacteriocin producer strains of lactic acid bacteria from a dairy environment.

PubMed

Lasagno, M; Beoleito, V; Sesma, F; Raya, R; Font de Valdez, G; Eraso, A

2002-01-01

Two strains showing bacteriocin production were selected from a total of 206 lactic acid bacteria isolated from samples of milk, milk serum, whey and homemade cheeses in Southern Cordoba, Argentina. This property was detected by means of well diffusion assays. The strains were identified as Enterococcus hirae and Enterococcus durans. The protein nature of those substances was proved by showing their sensitivity to type IV and XXV proteases, papaine, trypsin, pepsin and K proteinase. The bacteriocins inhibited the growth of Listeria monocytogenes, Bacillus cereus, Clostridium perfringes and two strains of Staphylococcus aureus, an A-enterotoxin and a B-enterotoxin producers. All of these bacteria are common pathogens usually associated with food borne diseases (ETA). These lactic acid bacteria or their bacteriocins could be suitable candidates for food preservation and specially useful in the our regional dairy industry.

The occurrence of pathogenic bacteria in some ships' ballast water incoming from various marine regions to the Sea of Marmara, Turkey.

PubMed

Altug, Gulsen; Gurun, Sevan; Cardak, Mine; Ciftci, Pelin S; Kalkan, Samet

2012-10-01

The composition and frequency of antibiotic resistance of pathogenic bacteria, the abundance of heterotrophic aerobic bacteria (HPC) and possible in-situ use of chromogenic agar were investigated in the ships' ballast water coming from different regions of the world to the Sea of Marmara, Turkey for the first time. The samples that were taken from 21 unit ships coming from various marine environments of the Southern China Sea, the Atlantic Ocean, the Mediterranean and the Black Sea to the Sea of Marmara, Turkey in 2009 and 2010 were tested. 38 bacteria species, 27 of them pathogenic bacteria belonging to 17 familia, were detected. Vibrio cholera was not detected in the samples. However, the presence of a high number of HPC, including a cocktail of pathogenic bacteria showed that the ships carry a potential risk for the Sea of Marmara. Copyright © 2012 Elsevier Ltd. All rights reserved.

Detection of Campylobacter jejuni in rectal swab samples from Rousettus amplexicaudatus in the Philippines.

PubMed

Hatta, Yuki; Omatsu, Tsutomu; Tsuchiaka, Shinobu; Katayama, Yukie; Taniguchi, Satoshi; Masangkay, Joseph S; Puentespina, Roberto; Eres, Eduardo; Cosico, Edison; Une, Yumi; Yoshikawa, Yasuhiro; Maeda, Ken; Kyuwa, Shigeru; Mizutani, Tetsuya

2016-09-01

Bats are the second diversity species of mammals and widely distributed in the world. They are thought to be reservoir and vectors of zoonotic pathogens. However, there is scarce report of the evidence of pathogenic bacteria kept in bats. The precise knowledge of the pathogenic bacteria in bat microbiota is important for zoonosis control. Thus, metagenomic analysis targeting the V3-V4 region of the 16S rRNA of the rectal microbiota in Rousettus amplexicaudatus was performed using high throughput sequencing. The results revealed that 103 genera of bacteria including Camplyobacter were detected. Campylobacter was second predominant genus, and Campylobacter coli and Campylobacter jejuni were identified in microbiome of R. amplexicaudatus. Campylobacteriosis is one of the serious bacterial diarrhea in human, and the most often implicated species as the causative agent of campylobacteriosis is C. jejuni. Therefore, we investigated the prevalence of C. jejuni in 91 wild bats with PCR. As a result of PCR assay targeted on 16S-23S intergenic spacer, partial genome of C. jejuni was detected only in five R. amplexicaudatus. This is the first report that C. jejuni was detected in bat rectal swab samples. C. jejuni is the most common cause of campylobacteriosis in humans, transmitted through water and contact with livestock animals. This result indicated that R. amplexicaudatus may be a carrier of C. jejuni.

Nonspecific aerobic vaginitis and pregnancy.

PubMed

Curzik, D; Drazancić, A; Hrgović, Z

2001-01-01

During the period 1996-1998, cervical swabs of 50 pregnant women with subacute amniotic infection syndrome (AIS) and the semen of their consorts were bacteriologically analyzed. In the control group were 50 healthy pregnant women and their consorts too. Pathogenic bacteria (the most common were Escherichia coli, Staphylococcus haemolyticus, Chlamydia trachomatis and Ureaplasma urealyticum) were isolated from the cervical swab of 50 pregnant patients with AIS in 86.0% of them, while in the control group of healthy pregnant women in 28.0%. Pathogenic bacteria were present in 70.0% of semen of consorts pregnant women with AIS and only in 30.0% of semen of the control group. The congruity of pathogenic bacteria in the cervical swab and semen in the investigated group was 69.2%, while only 35.7% in the control group. Following erythromycin, cefuroxime and local tetracyclin treatment, the negativization of the cervical swab resulted in 30 pregnant patients with AIS, while the colonization persisted in 20 of them. The outcome of pregnancy was significantly better in cases with negativization of the cervical swab: perinatal loss was 6.7%, while in cases with persistent infection it was 55.0%. The authors presume the amniotic infection syndrome should be ascending manifestation of nonspecific vaginitis, which is maintained by the consort's urogenital infection. AIS should be classified as a 'sexually-transmitted disease'. Copyright 2001 S. Karger AG, Basel

Livestock abundance predicts vampire bat demography, immune profiles and bacterial infection risk

PubMed Central

Czirják, Gábor Á.; Volokhov, Dmitriy V.; Carrera, Jorge E.; Camus, Melinda S.; Navara, Kristen J.; Chizhikov, Vladimir E.; Fenton, M. Brock; Simmons, Nancy B.; Recuenco, Sergio E.; Gilbert, Amy T.

2018-01-01

Human activities create novel food resources that can alter wildlife–pathogen interactions. If resources amplify or dampen, pathogen transmission probably depends on both host ecology and pathogen biology, but studies that measure responses to provisioning across both scales are rare. We tested these relationships with a 4-year study of 369 common vampire bats across 10 sites in Peru and Belize that differ in the abundance of livestock, an important anthropogenic food source. We quantified innate and adaptive immunity from bats and assessed infection with two common bacteria. We predicted that abundant livestock could reduce starvation and foraging effort, allowing for greater investments in immunity. Bats from high-livestock sites had higher microbicidal activity and proportions of neutrophils but lower immunoglobulin G and proportions of lymphocytes, suggesting more investment in innate relative to adaptive immunity and either greater chronic stress or pathogen exposure. This relationship was most pronounced in reproductive bats, which were also more common in high-livestock sites, suggesting feedbacks between demographic correlates of provisioning and immunity. Infection with both Bartonella and haemoplasmas were correlated with similar immune profiles, and both pathogens tended to be less prevalent in high-livestock sites, although effects were weaker for haemoplasmas. These differing responses to provisioning might therefore reflect distinct transmission processes. Predicting how provisioning alters host–pathogen interactions requires considering how both within-host processes and transmission modes respond to resource shifts. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’. PMID:29531144

Phylogenetic assessment of heterotrophic bacteria from a water distribution system using 16S rDNA sequencing.

PubMed

Tokajian, Sima T; Hashwa, Fuad A; Hancock, Ian C; Zalloua, Pierre A

2005-04-01

Determination of a heterotrophic plate count (HPC) for drinking-water samples alone is not enough to assess possible health hazards associated with sudden changes in the bacterial count. Speciation is very crucial to determine whether the population includes pathogens and (or) opportunistic pathogens. Most of the isolates recovered from drinking water samples could not be allocated to a specific phylogenetic branch based on the use of conventional diagnostic methods. The present study had to use phylogenetic analysis, which was simplified by determining and using the first 500-bp sequence of the 16S rDNA, to successfully identify the type and species of bacteria found in the samples. Gram-positive bacteria alpha-, beta-, and gamma-Proteobacteria were found to be the major groups representing the heterotrophic bacteria in drinking water. The study also revealed that the presence of sphingomonads in drinking water supplies may be much more common than has been reported so far and thus further studies are merited. The intermittent mode of supply, mainly characterized by water stagnation and flow interruption associated possibly with biofilm detachment, raised the possibility that the studied bacterial populations in such systems represented organisms coming from 2 different niches, the biofilm and the water column.

The bacterial segrosome: a dynamic nucleoprotein machine for DNA trafficking and segregation.

PubMed

Hayes, Finbarr; Barillà, Daniela

2006-02-01

The genomes of unicellular and multicellular organisms must be partitioned equitably in coordination with cytokinesis to ensure faithful transmission of duplicated genetic material to daughter cells. Bacteria use sophisticated molecular mechanisms to guarantee accurate segregation of both plasmids and chromosomes at cell division. Plasmid segregation is most commonly mediated by a Walker-type ATPase and one of many DNA-binding proteins that assemble on a cis-acting centromere to form a nucleoprotein complex (the segrosome) that mediates intracellular plasmid transport. Bacterial chromosome segregation involves a multipartite strategy in which several discrete protein complexes potentially participate. Shedding light on the basis of genome segregation in bacteria could indicate new strategies aimed at combating pathogenic and antibiotic-resistant bacteria.

A simplified experimental model for clearance of some pathogenic bacteria using common bacterivorous ciliated spp. in Tigris river

NASA Astrophysics Data System (ADS)

Ali, Talib Hassan; Saleh, Dhuha Saad

2014-03-01

Bacteria-specific uptake rates of three different protozoan taxa on a pure and mixed bacterial community was studied by means of a simplified and functionally reproducible experimental model. The bacterial species Shigella flexneri, Escherichia coli and Salmonella typhi were isolated and classified from stool samples of patients suffering from diarrhea. Paramecium caudatum, Tetrahymena pyriformis and Halteria grandinella, free living ciliate Protozoans, were isolated and identified from Tigris river water. Pure and mixed ( E. coli + S. typhi), ( E. coli + Sh. flexneri) bacterial cultures were used with each ciliate genera to evaluate the following: predator duplication rate, prey reduction rate, clearance rate and net grazing rate. We used selective lactose fermentation phenomena of enteric bacteria on MacConkey medium for the quantification of bacteria cultural characteristics. The final bacteria concentration was reduced by growing protozoa of 98-99.9 % compared to protozoa-free controls. It showed that Tetrahymena pyriformis had the highest duplication rate (4.13 time/day) in both types of cultures (pure and mixed), followed by Paramecium caudatum and Halteria grandinella, respectively. Paramecium caudatum had the highest rate of ingestion in both types of cultures (26 × 103 bacteria/organism/hr) and yielded the longest time required for 90 % bacterial reduction in a pure suspension of S. typhi (166 h). Clearance rates of pathogenic bacteria by ciliates ranged between 106 nanoliter/organism/h by P. caudatum to S. typhi and 1.92 nanoliter/organism/h seen in T. pyriformis in ( E. coli + S. typhi) mixed culture. We used aquatic experimental microcosms under controlled conditions to explore bacteria-dependent ciliate growth and examined whether these ciliates could discriminate between equally sized bacterial preys in a mixture.

Volatile compounds from beneficial or pathogenic bacteria differentially regulate root exudation, transcription of iron transporters, and defense signaling pathways in Sorghum bicolor.

PubMed

Hernández-Calderón, Erasto; Aviles-Garcia, Maria Elizabeth; Castulo-Rubio, Diana Yazmín; Macías-Rodríguez, Lourdes; Ramírez, Vicente Montejano; Santoyo, Gustavo; López-Bucio, José; Valencia-Cantero, Eduardo

2018-02-01

Our results show that Sorghum bicolor is able to recognize bacteria through its volatile compounds and differentially respond to beneficial or pathogens via eliciting nutritional or defense adaptive traits. Plants establish beneficial, harmful, or neutral relationships with bacteria. Plant growth promoting rhizobacteria (PGPR) emit volatile compounds (VCs), which may act as molecular cues influencing plant development, nutrition, and/or defense. In this study, we compared the effects of VCs produced by bacteria with different lifestyles, including Arthrobacter agilis UMCV2, Bacillus methylotrophicus M4-96, Sinorhizobium meliloti 1021, the plant pathogen Pseudomonas aeruginosa PAO1, and the commensal rhizobacterium Bacillus sp. L2-64, on S. bicolor. We show that VCs from all tested bacteria, except Bacillus sp. L2-64, increased biomass and chlorophyll content, and improved root architecture, but notheworthy A. agilis induced the release of attractant molecules, whereas P. aeruginosa activated the exudation of growth inhibitory compounds by roots. An analysis of the expression of iron-transporters SbIRT1, SbIRT2, SbYS1, and SbYS2 and genes related to plant defense pathways COI1 and PR-1 indicated that beneficial, pathogenic, and commensal bacteria could up-regulate iron transporters, whereas only beneficial and pathogenic species could induce a defense response. These results show how S. bicolor could recognize bacteria through their volatiles profiles and highlight that PGPR or pathogens can elicit nutritional or defensive traits in plants.

Engineered cationic antimicrobial peptides to overcome multidrug resistance by ESKAPE pathogens.

PubMed

Deslouches, Berthony; Steckbeck, Jonathan D; Craigo, Jodi K; Doi, Yohei; Burns, Jane L; Montelaro, Ronald C

2015-02-01

Multidrug resistance constitutes a threat to the medical achievements of the last 50 years. In this study, we demonstrated the abilities of two de novo engineered cationic antibiotic peptides (eCAPs), WLBU2 and WR12, to overcome resistance from 142 clinical isolates representing the most common multidrug-resistant (MDR) pathogens and to display a lower propensity to select for resistant bacteria in vitro compared to that with colistin and LL37. The results warrant an exploration of eCAPs for use in clinical settings. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Insect pathogenicity in plant-beneficial pseudomonads: phylogenetic distribution and comparative genomics.

PubMed

Flury, Pascale; Aellen, Nora; Ruffner, Beat; Péchy-Tarr, Maria; Fataar, Shakira; Metla, Zane; Dominguez-Ferreras, Ana; Bloemberg, Guido; Frey, Joachim; Goesmann, Alexander; Raaijmakers, Jos M; Duffy, Brion; Höfte, Monica; Blom, Jochen; Smits, Theo H M; Keel, Christoph; Maurhofer, Monika

2016-10-01

Bacteria of the genus Pseudomonas occupy diverse environments. The Pseudomonas fluorescens group is particularly well-known for its plant-beneficial properties including pathogen suppression. Recent observations that some strains of this group also cause lethal infections in insect larvae, however, point to a more versatile ecology of these bacteria. We show that 26 P. fluorescens group strains, isolated from three continents and covering three phylogenetically distinct sub-clades, exhibited different activities toward lepidopteran larvae, ranging from lethal to avirulent. All strains of sub-clade 1, which includes Pseudomonas chlororaphis and Pseudomonas protegens, were highly insecticidal regardless of their origin (animals, plants). Comparative genomics revealed that strains in this sub-clade possess specific traits allowing a switch between plant- and insect-associated lifestyles. We identified 90 genes unique to all highly insecticidal strains (sub-clade 1) and 117 genes common to all strains of sub-clade 1 and present in some moderately insecticidal strains of sub-clade 3. Mutational analysis of selected genes revealed the importance of chitinase C and phospholipase C in insect pathogenicity. The study provides insight into the genetic basis and phylogenetic distribution of traits defining insecticidal activity in plant-beneficial pseudomonads. Strains with potent dual activity against plant pathogens and herbivorous insects have great potential for use in integrated pest management for crops.

Insect pathogenicity in plant-beneficial pseudomonads: phylogenetic distribution and comparative genomics

PubMed Central

Flury, Pascale; Aellen, Nora; Ruffner, Beat; Péchy-Tarr, Maria; Fataar, Shakira; Metla, Zane; Dominguez-Ferreras, Ana; Bloemberg, Guido; Frey, Joachim; Goesmann, Alexander; Raaijmakers, Jos M; Duffy, Brion; Höfte, Monica; Blom, Jochen; Smits, Theo H M; Keel, Christoph; Maurhofer, Monika

2016-01-01

Bacteria of the genus Pseudomonas occupy diverse environments. The Pseudomonas fluorescens group is particularly well-known for its plant-beneficial properties including pathogen suppression. Recent observations that some strains of this group also cause lethal infections in insect larvae, however, point to a more versatile ecology of these bacteria. We show that 26 P. fluorescens group strains, isolated from three continents and covering three phylogenetically distinct sub-clades, exhibited different activities toward lepidopteran larvae, ranging from lethal to avirulent. All strains of sub-clade 1, which includes Pseudomonas chlororaphis and Pseudomonas protegens, were highly insecticidal regardless of their origin (animals, plants). Comparative genomics revealed that strains in this sub-clade possess specific traits allowing a switch between plant- and insect-associated lifestyles. We identified 90 genes unique to all highly insecticidal strains (sub-clade 1) and 117 genes common to all strains of sub-clade 1 and present in some moderately insecticidal strains of sub-clade 3. Mutational analysis of selected genes revealed the importance of chitinase C and phospholipase C in insect pathogenicity. The study provides insight into the genetic basis and phylogenetic distribution of traits defining insecticidal activity in plant-beneficial pseudomonads. Strains with potent dual activity against plant pathogens and herbivorous insects have great potential for use in integrated pest management for crops. PMID:26894448

Structural engineering of a phage lysin that targets Gram-negative pathogens

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

Lukacik, Petra; Barnard, Travis J.; Keller, Paul W.

Bacterial pathogens are becoming increasingly resistant to antibiotics. As an alternative therapeutic strategy, phage therapy reagents containing purified viral lysins have been developed against Gram-positive organisms but not against Gram-negative organisms due to the inability of these types of drugs to cross the bacterial outer membrane. We solved the crystal structures of a Yersinia pestis outer membrane transporter called FyuA and a bacterial toxin called pesticin that targets this transporter. FyuA is a {beta}-barrel membrane protein belonging to the family of TonB dependent transporters, whereas pesticin is a soluble protein with two domains, one that binds to FyuA and anothermore » that is structurally similar to phage T4 lysozyme. The structure of pesticin allowed us to design a phage therapy reagent comprised of the FyuA binding domain of pesticin fused to the N-terminus of T4 lysozyme. This hybrid toxin kills specific Yersinia and pathogenic E. coli strains and, importantly, can evade the pesticin immunity protein (Pim) giving it a distinct advantage over pesticin. Furthermore, because FyuA is required for virulence and is more common in pathogenic bacteria, the hybrid toxin also has the advantage of targeting primarily disease-causing bacteria rather than indiscriminately eliminating natural gut flora.« less

Improved Phytophthora resistance in commercial chickpea (Cicer arietinum) varieties negatively impacts symbiotic gene signalling and symbiotic potential in some varieties.

PubMed

Plett, Jonathan M; Plett, Krista L; Bithell, Sean L; Mitchell, Chris; Moore, Kevin; Powell, Jeff R; Anderson, Ian C

2016-08-01

Breeding disease-resistant varieties is one of the most effective and economical means to combat soilborne diseases in pulse crops. Commonalities between pathogenic and mutualistic microbe colonization strategies, however, raises the concern that reduced susceptibility to pathogens may simultaneously reduce colonization by beneficial microbes. We investigate here the degree of overlap in the transcriptional response of the Phytophthora medicaginis susceptible chickpea variety 'Sonali' to the early colonization stages of either Phytophthora, rhizobial bacteria or arbuscular mycorrhizal fungi. From a total of 6476 genes differentially expressed in Sonali roots during colonization by any of the microbes tested, 10.2% were regulated in a similar manner regardless of whether it was the pathogenic oomycete or a mutualistic microbe colonizing the roots. Of these genes, 49.7% were oppositely regulated under the same conditions in the moderately Phytophthora resistant chickpea variety 'PBA HatTrick'. Chickpea varieties with improved resistance to Phytophthora also displayed lower colonization by rhizobial bacteria and mycorrhizal fungi leading to an increased reliance on N and P from soil. Together, our results suggest that marker-based breeding in crops such as chickpea should be further investigated such that plant disease resistance can be tailored to a specific pathogen without affecting mutualistic plant:microbe interactions. © 2016 John Wiley & Sons Ltd.

Toward a Metagenomic Understanding on the Bacterial Composition and Resistome in Hong Kong Banknotes

PubMed Central

Heshiki, Yoshitaro; Dissanayake, Thrimendra; Zheng, Tingting; Kang, Kang; Yueqiong, Ni; Xu, Zeling; Sarkar, Chinmoy; Woo, Patrick C. Y.; Chow, Billy K. C.; Baker, David; Yan, Aixin; Webster, Christopher J.; Panagiotou, Gianni; Li, Jun

2017-01-01

Currency is possibly one of the main media transmitting pathogens and drug resistance due to its wide circulation in daily life. In this study, we made a comprehensive characterization of the bacterial community present on banknotes collected from different geographical regions of Hong Kong (HK) by performing in vitro characterization of the bacterial presence and resistome profile, as well as metagenomic analysis including microbial diversity, the prevalence of potential pathogens, the dissemination potential of antibiotic-resistance genes (ARGs), among others. When comparing the bacterial community of HK banknotes with other HK environmental samples, including water and marine sediment, we revealed that HK banknotes cover nearly 50% of total genera found in all the environmental samples, implying that banknotes harbor diverse bacteria originated from a variety of environments. Furthermore, the banknotes have higher abundance of potential pathogenic species (~5 times more) and ARGs (~5 times more) with higher dissemination potential (~48 times more) compared with other environmental samples. These findings unveiled the capabilities of this common medium of exchange to accommodate various bacteria, and transmit pathogens and antibiotic resistance. Furthermore, the observed independence of microbiome profile from the city's topological indices led us to formulate a hypothesis that due to their high circulation banknotes may harbor a homogenized microbiome. PMID:28450856

A single genetic locus in the phytopathogen Pantoea stewartii enables gut colonization and pathogenicity in an insect host.

PubMed

Stavrinides, John; No, Alexander; Ochman, Howard

2010-01-01

Aphids are typically exposed to a variety of epiphytic and phytopathogenic bacteria, many of which have entomopathogenic potential. Here we describe the interaction between Pantoea stewartii ssp. stewartii DC283 (DC283), an enteric phytopathogen and causal agent of Stewart's wilt, and the pea aphid, Acyrthosiphon pisum. When ingested by aphids, DC283 establishes and aggregates in the crop and gut, preventing honeydew flow and excretion, resulting in aphid death in 72 h. A mutagenesis screen identified a single locus, termed ucp1 (youcannot pass), whose disruption abolishes aphid pathogenicity. Moreover, the expression of ucp1 in Escherichia coli is sufficient to mediate the hindgut aggregation phenotype by this normally avirulent species. Ucp1 is related to six other proteins in the DC283 genome, each having a common N-terminal region and a divergent C-terminus, but only ucp1 has a role in pathogenicity. Based on predicted motifs and secondary structure, Ucp1 is a membrane-bound protein that functions in bacterial adhesion and promotes the formation of aggregates that are lethal to the insect host. These results illustrate that the enteric plant pathogenic bacteria have the capacity to exploit alternative non-plant hosts, and retain genetic determinants for colonizing the gut.

Toward a Metagenomic Understanding on the Bacterial Composition and Resistome in Hong Kong Banknotes.

PubMed

Heshiki, Yoshitaro; Dissanayake, Thrimendra; Zheng, Tingting; Kang, Kang; Yueqiong, Ni; Xu, Zeling; Sarkar, Chinmoy; Woo, Patrick C Y; Chow, Billy K C; Baker, David; Yan, Aixin; Webster, Christopher J; Panagiotou, Gianni; Li, Jun

2017-01-01

Currency is possibly one of the main media transmitting pathogens and drug resistance due to its wide circulation in daily life. In this study, we made a comprehensive characterization of the bacterial community present on banknotes collected from different geographical regions of Hong Kong (HK) by performing in vitro characterization of the bacterial presence and resistome profile, as well as metagenomic analysis including microbial diversity, the prevalence of potential pathogens, the dissemination potential of antibiotic-resistance genes (ARGs), among others. When comparing the bacterial community of HK banknotes with other HK environmental samples, including water and marine sediment, we revealed that HK banknotes cover nearly 50% of total genera found in all the environmental samples, implying that banknotes harbor diverse bacteria originated from a variety of environments. Furthermore, the banknotes have higher abundance of potential pathogenic species (~5 times more) and ARGs (~5 times more) with higher dissemination potential (~48 times more) compared with other environmental samples. These findings unveiled the capabilities of this common medium of exchange to accommodate various bacteria, and transmit pathogens and antibiotic resistance. Furthermore, the observed independence of microbiome profile from the city's topological indices led us to formulate a hypothesis that due to their high circulation banknotes may harbor a homogenized microbiome.

A Rab-centric perspective of bacterial pathogen-occupied vacuoles.

PubMed

Sherwood, Racquel Kim; Roy, Craig R

2013-09-11

The ability to create and maintain a specialized organelle that supports bacterial replication is an important virulence property for many intracellular pathogens. Living in a membrane-bound vacuole presents inherent challenges, including the need to remodel a plasma membrane-derived organelle into a novel structure that will expand and provide essential nutrients to support replication, while also having the vacuole avoid membrane transport pathways that target bacteria for destruction in lysosomes. It is clear that pathogenic bacteria use different strategies to accomplish these tasks. The dynamics by which host Rab GTPases associate with pathogen-occupied vacuoles provide insight into the mechanisms used by different bacteria to manipulate host membrane transport. In this review we highlight some of the strategies bacteria use to maintain a pathogen-occupied vacuole by focusing on the Rab proteins involved in biogenesis and maintenance of these novel organelles. Copyright © 2013 Elsevier Inc. All rights reserved.

Antibacterial activity of plant extracts on foodborne bacterial pathogens and food spoilage bacteria

USDA-ARS?s Scientific Manuscript database

Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...

Duplex Identification of Staphylococcus aureus by Aptamer and Gold Nanoparticles.

PubMed

Chang, Tianjun; Wang, Libo; Zhao, Kexu; Ge, Yu; He, Meng; Li, Gang

2016-06-01

Staphylococcus aureus is the top common pathogen causing infections and food poisoning. Identification of S. aureus is crucial for the disease diagnosis and regulation of food hygiene. Herein, we report an aptamer-AuNPs based method for duplex identification of S. aureus. Using AuNPs as an indicator, SA23, an aptamer against S. aureus, can well identify its target from Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa. Furthermore, we find citrate-coated AuNPs can strongly bind to S. aureus, but not bind to Salmonella enterica and Proteus mirabilis, which leads to different color changes in salt solution. This colorimetric response is capable of distinguishing S. aureus from S. enteritidis and P. mirabilis. Thus, using the aptasensor and AuNPs together, S. aureus can be accurately identified from the common pathogens. This duplex identification system is a promising platform for simple visual identification of S. aureus. Additionally, in the aptasensing process, bacteria are incubated with aptamers and then be removed before the aptamers adding to AuNPs, which may avoid the interactions between bacteria and AuNPs. This strategy can be potentially applied in principle to detect other cells by AuNPs-based aptasensors.

Cystic fibrosis pathogens survive for extended periods within cough-generated droplet nuclei.

PubMed

Wood, Michelle E; Stockwell, Rebecca E; Johnson, Graham R; Ramsay, Kay A; Sherrard, Laura J; Kidd, Timothy J; Cheney, Joyce; Ballard, Emma L; O'Rourke, Peter; Jabbour, Nassib; Wainwright, Claire E; Knibbs, Luke D; Sly, Peter D; Morawska, Lidia; Bell, Scott C

2018-04-07

The airborne route is a potential pathway in the person-to-person transmission of bacterial strains among cystic fibrosis (CF) populations. In this cross-sectional study, we investigate the physical properties and survival of common non- Pseudomonas aeruginosa CF pathogens generated during coughing. We conclude that Gram-negative bacteria and Staphylococcus aureus are aerosolised during coughing, can travel up to 4 m and remain viable within droplet nuclei for up to 45 min. These results suggest that airborne person-to-person transmission is plausible for the CF pathogens we measured. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Pathogen Presence in European Starlings Inhabiting Commercial Piggeries in South Australia.

PubMed

Pearson, Hayley E; Lapidge, Steven J; Hernández-Jover, Marta; Toribio, Jenny-Ann L M L

2016-06-01

The majority of bacterial diarrhea-causing illnesses in domestic pigs result from infection with Escherichia coli, Salmonella spp., or Campylobacter spp. These bacterial enteropathogens also correspond with the most-common bacteria isolated from wild birds. Additionally, viral pathogens such as avian influenza virus (AIV), West Nile virus (WNV, including Kunjin disease), and Newcastle disease virus (NDV) may also be carried and transmitted by birds in Australia. Introduced European starlings (Sturnus vulgarus) are one of the most-frequently reported birds on piggeries in Australia. The presence of the three bacterial pathogens, Salmonella spp., Campylobacter spp., and Escherichia coli , as well as the three viral pathogens AIV, WNV, and NDV, were evaluated in starlings captured on four commercial piggeries in South Australia. A total of 473 starlings were captured on the four piggeries in 2008 and 2009. A cloacal swab was taken from each bird and cultured for bacterial identification, with follow-up serotyping of any positives, whilst fifty samples were analyzed by PCR for the three target viral pathogens. There was no AIV, WNV, or NDV detected in the 50 starlings sampled. Escherichia coli was found to be present in the starling populations on all four piggeries whilst Salmonella spp. and Campylobacter jejuni were found to be present only in the starling population sampled on one piggery. Serotyping identified pig-pathogenic strains of the bacteria. The prevalence of these production-limiting bacterial pathogens in starlings, coupled with the large starling populations often found inside piggeries during daylight hours in the summer months, presents a disease transmission risk and jeopardizes piggery disease management. Removal of starlings from agricultural enterprises (as shown by international studies), or prevention of starling access to animal feed and water, could substantially reduce the risk of transmission of enterobacterial pathogens from starlings to livestock.

Comprehensive list of names of plant pathogenic bacteria, 1980-2007.

USDA-ARS?s Scientific Manuscript database

This list contains the names of all plant pathogenic bacteria which have been effectively and validly published in terms of the International Code of Nomenclature of Bacteria and the Standards for Naming Pathovars and their revisions. Included are species names from the Approved Lists of Bacterial N...

Ciliate ingestion and digestion: flow cytometric measurements and regrowth of a digestion-resistant campylobacter jejuni

USDA-ARS?s Scientific Manuscript database

We developed a method to measure ingestion and digestion rates of bacterivorous protists feeding on pathogenic bacteria. We tested this method using the enteric bacteria Campylobacter jejuni and a freshwater colpodid ciliate. Campylobacter and a non-pathogenic bacteria isolated from the environment ...

Protein-linked glycans in periodontal bacteria: prevalence and role at the immune interface.

PubMed

Settem, Rajendra P; Honma, Kiyonobu; Stafford, Graham P; Sharma, Ashu

2013-10-17

Protein modification with complex glycans is increasingly being recognized in many pathogenic and non-pathogenic bacteria, and is now thought to be central to the successful life-style of those species in their respective hosts. This review aims to convey current knowledge on the extent of protein glycosylation in periodontal pathogenic bacteria and its role in the modulation of the host immune responses. The available data show that surface glycans of periodontal bacteria orchestrate dendritic cell cytokine responses to drive T cell immunity in ways that facilitate bacterial persistence in the host and induce periodontal inflammation. In addition, surface glycans may help certain periodontal bacteria protect against serum complement attack or help them escape immune detection through glycomimicry. In this review we will focus mainly on the generalized surface-layer protein glycosylation system of the periodontal pathogen Tannerella forsythia in shaping innate and adaptive host immunity in the context of periodontal disease. In addition, we will also review the current state of knowledge of surface protein glycosylation and its potential for immune modulation in other periodontal pathogens.

Estimation of decay rates for fecal indicator bacteria and bacterial pathogens in agricultural field-applied manure

EPA Science Inventory

Field-applied manure is an important source of pathogenic exposure in surface water bodies for humans and ecological receptors. We analyzed the persistence and decay of fecal indicator bacteria and bacterial pathogens from three sources (cattle, poultry, swine) for agricultural f...

A microsensor for the detection of a single pathogenic bacterium using magnetotactic bacteria-based bio-carriers: simulations and preliminary experiments.

PubMed

Denomme, Ryan C; Lu, Zhao; Martel, Sylvain

2007-01-01

The proposed Magnetotactic Bacteria (MTB) based bio-carrier has the potential to greatly improve pathogenic bacteria detection time, specificity, and sensitivity. Microbeads are attached to the MTB and are modified with a coating of an antibody or phage that is specific to the target pathogenic bacteria. Using magnetic fields, the modified MTB are swept through a solution and the target bacteria present become attached to the microbeads (due to the coating). Then, the MTB are brought to the detection region and the number of pathogenic bacteria is determined. The high swimming speed and controllability of the MTB make this method ideal for the fast detection of small concentrations of specific bacteria. This paper focuses on an impedimetric detection system that will be used to identify if a target bacterium is attached to the microbead. The proposed detection system measures changes in electrical impedance as objects (MTB, microbeads, and pathogenic bacteria) pass through a set of microelectrodes embedded in a microfluidic device. FEM simulation is used to acquire the optimized parameters for the design of such a system. Specifically, factors such as electrode/detection channel geometry, object size and position, which have direct effects on the detection sensitivity for a single bacterium or microparticle, are investigated. Polymer microbeads and the MTB system with an E. coli bacterium are considered to investigate their impedance variations. Furthermore, preliminary experimental data using a microfabricated microfluidic device connected to an impedance analyzer are presented.

A mathematical model for expected time to extinction of pathogenic bacteria through antibiotic

NASA Astrophysics Data System (ADS)

Ghosh, M. K.; Nandi, S.; Roy, P. K.

2016-04-01

Application of antibiotics in human system to prevent bacterial diseases like Gastritis, Ulcers, Meningitis, Pneumonia and Gonorrhea are indispensable. Antibiotics saved innumerable lives and continue to be a strong support for therapeutic application against pathogenic bacteria. In human system, bacterial diseases occur when pathogenic bacteria gets into the body and begin to reproduce and crowd out healthy bacteria. In this process, immature bacteria releases enzyme which is essential for bacterial cell-wall biosynthesis. After complete formation of cell wall, immature bacteria are converted to mature or virulent bacteria which are harmful to us during bacterial infections. Use of antibiotics as drug inhibits the bacterial cell wall formation. After application of antibiotics within body, the released bacterial enzyme binds with antibiotic molecule instead of its functional site during the cell wall synthesis in a competitive inhibition approach. As a consequence, the bacterial cell-wall formation as well as maturation process of pathogenic bacteria is halted and the disease is cured with lysis of bacterial cells. With this idea, a mathematical model has been developed in the present research investigation to review the inhibition of biosynthesis of bacterial cell wall by the application of antibiotics as drug in the light of enzyme kinetics. This approach helps to estimate the expected time to extinction of the pathogenic bacteria. Our mathematical approach based on the enzyme kinetic model for finding out expected time to extinction contributes favorable results for understanding of disease dynamics. Analytical and numerical results based on simulated findings validate our mathematical model.

Human and bovine viruses and bacteria at three Great Lakes beaches: Environmental variable associations and health risk

USGS Publications Warehouse

Corsi, Steven R.; Borchardt, Mark A.; Carvin, Rebecca B.; Burch, Tucker R; Spencer, Susan K.; Lutz, Michelle A.; McDermott, Colleen M.; Busse, Kimberly M.; Kleinheinz, Gregory; Feng, Xiaoping; Zhu, Jun

2016-01-01

Waterborne pathogens were measured at three beaches in Lake Michigan, environmental factors for predicting pathogen concentrations were identified, and the risk of swimmer infection and illness was estimated. Waterborne pathogens were detected in 96% of samples collected at three Lake Michigan beaches in summer, 2010. Samples were quantified for 22 pathogens in four microbial categories (human viruses, bovine viruses, protozoa, and pathogenic bacteria). All beaches had detections of human and bovine viruses and pathogenic bacteria indicating influence of multiple contamination sources at these beaches. Occurrence ranged from 40 to 87% for human viruses, 65–87% for pathogenic bacteria, and 13–35% for bovine viruses. Enterovirus, adenovirus A, Salmonella spp., Campylobacter jejuni, bovine polyomavirus, and bovine rotavirus A were present most frequently. Variables selected in multiple regression models used to explore environmental factors that influence pathogens included wave direction, cloud cover, currents, and water temperature. Quantitative Microbial Risk Assessment was done for C. jejuni, Salmonella spp., and enteroviruses to estimate risk of infection and illness. Median infection risks for one-time swimming events were approximately 3 × 10–5, 7 × 10–9, and 3 × 10–7 for C. jejuni, Salmonella spp., and enteroviruses, respectively. Results highlight the importance of investigating multiple pathogens within multiple categories to avoid underestimating the prevalence and risk of waterborne pathogens.

Distribution of triclosan-resistant genes in major pathogenic microorganisms revealed by metagenome and genome-wide analysis

PubMed Central

Khan, Raees; Roy, Nazish; Choi, Kihyuck

2018-01-01

The substantial use of triclosan (TCS) has been aimed to kill pathogenic bacteria, but TCS resistance seems to be prevalent in microbial species and limited knowledge exists about TCS resistance determinants in a majority of pathogenic bacteria. We aimed to evaluate the distribution of TCS resistance determinants in major pathogenic bacteria (N = 231) and to assess the enrichment of potentially pathogenic genera in TCS contaminated environments. A TCS-resistant gene (TRG) database was constructed and experimentally validated to predict TCS resistance in major pathogenic bacteria. Genome-wide in silico analysis was performed to define the distribution of TCS-resistant determinants in major pathogens. Microbiome analysis of TCS contaminated soil samples was also performed to investigate the abundance of TCS-resistant pathogens. We experimentally confirmed that TCS resistance could be accurately predicted using genome-wide in silico analysis against TRG database. Predicted TCS resistant phenotypes were observed in all of the tested bacterial strains (N = 17), and heterologous expression of selected TCS resistant genes from those strains conferred expected levels of TCS resistance in an alternative host Escherichia coli. Moreover, genome-wide analysis revealed that potential TCS resistance determinants were abundant among the majority of human-associated pathogens (79%) and soil-borne plant pathogenic bacteria (98%). These included a variety of enoyl-acyl carrier protein reductase (ENRs) homologues, AcrB efflux pumps, and ENR substitutions. FabI ENR, which is the only known effective target for TCS, was either co-localized with other TCS resistance determinants or had TCS resistance-associated substitutions. Furthermore, microbiome analysis revealed that pathogenic genera with intrinsic TCS-resistant determinants exist in TCS contaminated environments. We conclude that TCS may not be as effective against the majority of bacterial pathogens as previously presumed. Further, the excessive use of this biocide in natural environments may selectively enrich for not only TCS-resistant bacterial pathogens, but possibly for additional resistance to multiple antibiotics. PMID:29420585

Antibacterial Properties of Endophytic Bacteria Isolated from a Fern Species Equisetum arvense L. Against Foodborne Pathogenic Bacteria Staphylococcus aureus and Escherichia coli O157:H7.

PubMed

Das, Gitishree; Patra, Jayanta Kumar; Baek, Kwang-Hyun

2017-01-01

Endophytic bacteria (EB) are a rich source of secondary metabolites with medicinal importance. In this study, EB were isolated from the bottle brush herb Equisetum arvense and identified based on 16S rRNA sequencing. Evaluation of its antibacterial potential was conducted using two common foodborne pathogenic bacteria, Staphylococcus aureus ATCC 12600 and Escherichia coli O157:H7 ATCC 43890. Out of 103 identified EB, three species, Streptomyces albolongus, Dermacoccus sp., and Mycobacterium sp., showed significant antibacterial activity against S. aureus with inhibition zones of 45.34 ± 0.15, 43.28 ± 0.19, and 22.98 ± 0.18 mm, respectively, whereas only two species, Streptomyces griseoaurantiacus (EAL196) and Paenibacillus sp. (EAS116), showed moderate antibacterial activity against E. coli O157:H7 with inhibition zones of 9.41 ± 0.29 and 10.44 ± 0.31 mm, respectively. Furthermore, ethyl acetate extract of S. albolongus, Mycobacterium sp., and Dermacoccus sp. showed antibacterial activity against S. aureus, with inhibition zones of 23.43 ± 0.21, 21.18 ± 0.22, and 19.72 ± 0.10 mm, respectively. The methanol extract of Dermacoccus sp. and Paenibacillus sp. showed antibacterial activity against S. aureus and E. coli O157:H7, with inhibition zones of 11.30 ± 0.17 and 10.01 ± 0.21 mm, respectively. Scanning electron microscopy indicated swollen and lysed cell membranes of pathogens treated with ethyl acetate extract. A possible reason might be, likely due to EB metabolites penetrating the bacterial cell membranes and affecting various metabolic functions resulting in lysis. To the best of our knowledge, this is the first study to report that EB from E. arvense can be used as a source of natural antibacterial compounds against foodborne pathogenic bacteria.

Bacillus anthracis Overcomes an Amino Acid Auxotrophy by Cleaving Host Serum Proteins

PubMed Central

Terwilliger, Austen; Swick, Michelle C.; Pflughoeft, Kathryn J.; Pomerantsev, Andrei; Lyons, C. Rick; Koehler, Theresa M.

2015-01-01

ABSTRACT Bacteria sustain an infection by acquiring nutrients from the host to support replication. The host sequesters these nutrients as a growth-restricting strategy, a concept termed “nutritional immunity.” Historically, the study of nutritional immunity has centered on iron uptake because many bacteria target hemoglobin, an abundant circulating protein, as an iron source. Left unresolved are the mechanisms that bacteria use to attain other nutrients from host sources, including amino acids. We employed a novel medium designed to mimic the chemical composition of human serum, and we show here that Bacillus anthracis, the causative agent of anthrax disease, proteolyzes human hemoglobin to liberate essential amino acids which enhance its growth. This property can be traced to the actions of InhA1, a secreted metalloprotease, and extends to at least three other serum proteins, including serum albumin. The results suggest that we must also consider proteolysis of key host proteins to be a way for bacterial pathogens to attain essential nutrients, and we provide an experimental framework to determine the host and bacterial factors involved in this process. IMPORTANCE The mechanisms by which bacterial pathogens acquire nutrients during infection are poorly understood. Here we used a novel defined medium that approximates the chemical composition of human blood serum, blood serum mimic (BSM), to better model the nutritional environment that pathogens encounter during bacteremia. Removing essential amino acids from BSM revealed that two of the most abundant proteins in blood—hemoglobin and serum albumin—can satiate the amino acid requirement for Bacillus anthracis, the causative agent of anthrax. We further demonstrate that hemoglobin is proteolyzed by the secreted protease InhA1. These studies highlight that common blood proteins can be a nutrient source for bacteria. They also challenge the historical view that hemoglobin is solely an iron source for bacterial pathogens. PMID:25962917

Genome-wide detection of conservative site-specific recombination in bacteria

PubMed Central

Mathias Garrett, Elizabeth; Camilli, Andrew

2018-01-01

The ability of clonal bacterial populations to generate genomic and phenotypic heterogeneity is thought to be of great importance for many commensal and pathogenic bacteria. One common mechanism contributing to diversity formation relies on the inversion of small genomic DNA segments in a process commonly referred to as conservative site-specific recombination. This phenomenon is known to occur in several bacterial lineages, however it remains notoriously difficult to identify due to the lack of conserved features. Here, we report an easy-to-implement method based on high-throughput paired-end sequencing for genome-wide detection of conservative site-specific recombination on a single-nucleotide level. We demonstrate the effectiveness of the method by successfully detecting several novel inversion sites in an epidemic isolate of the enteric pathogen Clostridium difficile. Using an experimental approach, we validate the inversion potential of all detected sites in C. difficile and quantify their prevalence during exponential and stationary growth in vitro. In addition, we demonstrate that the master recombinase RecV is responsible for the inversion of some but not all invertible sites. Using a fluorescent gene-reporter system, we show that at least one gene from a two-component system located next to an invertible site is expressed in an on-off mode reminiscent of phase variation. We further demonstrate the applicability of our method by mining 209 publicly available sequencing datasets and show that conservative site-specific recombination is common in the bacterial realm but appears to be absent in some lineages. Finally, we show that the gene content associated with the inversion sites is diverse and goes beyond traditionally described surface components. Overall, our method provides a robust platform for detection of conservative site-specific recombination in bacteria and opens a new avenue for global exploration of this important phenomenon. PMID:29621238

Inhibition of Escherichia coli O157:H7 and Clostridium sporogenes in spinach packaged in modified atmospheres after treatment combined with chlorine and lactic acid bacteria.

PubMed

Brown, Alison L; Brooks, J Chance; Karunasena, Enusha; Echeverry, Alejandro; Laury, Angela; Brashears, Mindy M

2011-08-01

Implementation of modified atmospheric packaging (MAP) into retail produce is a less commonly practiced method due to differences among commodities and the potential growth of anaerobes. Pathogens including Escherichia coli O157:H7 have been responsible for spinach outbreaks across the United States. In this study, hurdles, including those currently used with produce safety, such as MAP and chlorine, were combined with lactic acid bacteria (LAB) to inhibit pathogens. Spinach was coinoculated with E. coli O157:H7 and Clostridium sporogenes, a surrogate for C. botulinum, and treated with water or a hurdle that included water, chlorine, and LAB. Spinach from treatments were packaged in air (traditional), oxygen (80% O₂, 20% CO₂), or nitrogen (80% N₂, 20% CO₂) and stored in a retail display case for 9 d at 4 to 7 °C. The hurdle inhibited E. coli O157:H7 and C. sporogenes compared to controls with reductions of 1.43 and 1.10 log (P < 0.05), respectively. The nitrogen atmosphere was outperformed by air and oxygen in the reduction of E. coli O157:H7 (P < 0.05) with a decrease of 0.26 and 0.15 logs. There were no significant differences among the 3 atmospheres on C. sporogenes survival. Relative to these hurdles, we also chose to evaluate the potential benefits of LAB in pathogen control. The survival of LAB in interventions demonstrates implementation of LAB into produce could control pathogens, without damaging produce or altering organoleptic properties. The goal of our work was to identify methods that could reduce food-borne pathogens in packaged spinach products. Using current industry techniques in combination with unique methods, such as the use of beneficial bacteria, our research identified whether harmful microorganisms could be eliminated. Our data demonstrate that specific packaging conditions with beneficial bacteria can help eliminate or reduce the survival of E. coli O157:H7 and C. sporogenes (a model for C. botulinum) in produce. Journal of Food Science © 2011 Institute of Food Technologists® No claim to original US government works.

Antibacterial Activities of Endophytic Bacteria Isolated from Taxus brevifolia Against Foodborne Pathogenic Bacteria.

PubMed

Islam, Nurul; Choi, Jaehyuk; Baek, Kwang-Hyun

2018-05-01

Endophytes are a potential source of novel bioactive compounds with medicinal properties. In this study, 41 endophytic bacteria (EB) were isolated from tissues of a medicinally important plant Taxus brevifolia (Pacific yew). The objective was to screen all the EB isolates for their antibacterial effects against five foodborne pathogenic bacteria: Bacillus cereus ATCC10876, Staphylococcus aureus ATCC12600, Listeria monocytogenes ATCC19115, Escherichia coli ATCC43890, and Salmonella Typhimurium ATCC19585. Among the EB isolates, T. brevifolia seed (TbS)-8, T. brevifolia fleshy part of fruit (TbFl)-10, T. brevifolia leaf (TbL)-22, TbS-29, and TbL-34 exerted significant antibacterial activity against the tested foodborne pathogens. Especially TbFl-10 showed the highest antibacterial activity against all the tested bacteria and was identified as Paenibacillus kribbensis (Pk). Furthermore, an ethyl acetate extract of Pk-TbFl-10 possessed antibacterial activities against the tested five foodborne pathogenic bacteria, with zones of inhibition from 15.71 ± 2.85 to 13.01 ± 2.12 mm. Scanning electron microscopy analysis revealed ruptured, lysed, shrunk, and swollen cells of all the tested foodborne pathogens treated with the ethyl acetate extract of Pk-TbFl-10, suggesting that a metabolite(s) of Pk-TbFl-10 penetrates the cell membrane and causes cell lysis leading to cell death. Our results indicate that Pk-TbFl-10 isolated from T. brevifolia can serve as a novel source of natural antibacterial agents against foodborne pathogenic bacteria, with potential applications in the pharmaceutical industry.

Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells.

PubMed

Wunsch, Christopher M; Lewis, Janina P

2015-12-17

Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and frequently of indigenous origin. The ability of some anaerobic pathogens to invade human cells gives them adaptive measures to escape innate immunity as well as to modulate host cell behavior. However, ensuring that the anaerobic bacteria are live during experimental investigation of the events may pose challenges. Porphyromonas gingivalis, a Gram-negative anaerobe, is capable of invading a variety of eukaryotic non-phagocytic cells. This article outlines how to successfully culture and assess the ability of P. gingivalis to invade human umbilical vein endothelial cells (HUVECs). Two protocols were developed: one to measure bacteria that can successfully invade and survive within the host, and the other to visualize bacteria interacting with host cells. These techniques necessitate the use of an anaerobic chamber to supply P. gingivalis with an anaerobic environment for optimal growth. The first protocol is based on the antibiotic protection assay, which is largely used to study the invasion of host cells by bacteria. However, the antibiotic protection assay is limited; only intracellular bacteria that are culturable following antibiotic treatment and host cell lysis are measured. To assess all bacteria interacting with host cells, both live and dead, we developed a protocol that uses fluorescent microscopy to examine host-pathogen interaction. Bacteria are fluorescently labeled with 2',7'-Bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and used to infect eukaryotic cells under anaerobic conditions. Following fixing with paraformaldehyde and permeabilization with 0.2% Triton X-100, host cells are labeled with TRITC phalloidin and DAPI to label the cell cytoskeleton and nucleus, respectively. Multiple images taken at different focal points (Z-stack) are obtained for temporal-spatial visualization of bacteria. Methods used in this study can be applied to any cultivable anaerobe and any eukaryotic cell type.

Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells

PubMed Central

Wunsch, Christopher M.; Lewis, Janina P.

2015-01-01

Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and frequently of indigenous origin. The ability of some anaerobic pathogens to invade human cells gives them adaptive measures to escape innate immunity as well as to modulate host cell behavior. However, ensuring that the anaerobic bacteria are live during experimental investigation of the events may pose challenges. Porphyromonas gingivalis, a Gram-negative anaerobe, is capable of invading a variety of eukaryotic non-phagocytic cells. This article outlines how to successfully culture and assess the ability of P. gingivalis to invade human umbilical vein endothelial cells (HUVECs). Two protocols were developed: one to measure bacteria that can successfully invade and survive within the host, and the other to visualize bacteria interacting with host cells. These techniques necessitate the use of an anaerobic chamber to supply P. gingivalis with an anaerobic environment for optimal growth. The first protocol is based on the antibiotic protection assay, which is largely used to study the invasion of host cells by bacteria. However, the antibiotic protection assay is limited; only intracellular bacteria that are culturable following antibiotic treatment and host cell lysis are measured. To assess all bacteria interacting with host cells, both live and dead, we developed a protocol that uses fluorescent microscopy to examine host-pathogen interaction. Bacteria are fluorescently labeled with 2',7'-Bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and used to infect eukaryotic cells under anaerobic conditions. Following fixing with paraformaldehyde and permeabilization with 0.2% Triton X-100, host cells are labeled with TRITC phalloidin and DAPI to label the cell cytoskeleton and nucleus, respectively. Multiple images taken at different focal points (Z-stack) are obtained for temporal-spatial visualization of bacteria. Methods used in this study can be applied to any cultivable anaerobe and any eukaryotic cell type. PMID:26709454

Colonisation of antibiotic resistant bacteria in a cohort of HIV infected children in Ghana.

PubMed

Sampane-Donkor, Eric; Badoe, Ebenezer Vincent; Annan, Jennifer Adoley; Nii-Trebi, Nicholas

2017-01-01

Antibiotic use not only selects for resistance in pathogenic bacteria, but also in commensal flora of exposed individuals. Little is known epidemiologically about antibiotic resistance in relation to people with HIV infection in sub-Saharan Africa. This study investigated the carriage of antibiotic resistant bacteria among HIV infected children at a tertiary hospital in Ghana. One hundred and eighteen HIV positive children were recruited at the Korle-Bu Teaching Hospital in Ghana and nasopharyngeal specimens were collected from them. The specimens were cultured for bacteria, and the isolates were identified by standard microbiological methods. Antibiotic susceptibility tests were carried out on selected bacterial organisms by the Kirby Bauer method. Bacteria isolated from the study subjects included Moraxella catarrhalis (39.8%), coagulase negative staphylococci (33.1%), Streptococcus pneumoniae (30.5%), diptheroids (29.7%), viridian streptococci (27.1%), Staphylococcus aureus (22.0%), Citrobacter spp. (4.2%) and Neisseria meningitidis (0.9%). Prevalence of antibiotic resistance of S. pneumoniae ranged from 5.6% (ceftriaxone) to 58.3% (cotrimoxazole), M. catarrhalis ranged from 2.1% (gentamicin) to 80.6% (ampicillin), and S. aureus ranged from 7.7% (cefoxitin) to 100% (penicillin). The prevalence of multiple drug resistance was 16.7% for S. pneumoniae, 57.4% for M. catarrhalis and 84.6% for S. aureus. HIV infected children in the study area commonly carry multi-drug resistant isolates of several pathogenic bacteria such as S. aureus and S. pneumoniae. Infections arising in these patients that are caused by S. aureus and S. pneumoniae could be treated with ceftriaxone and cefoxitin respectively.

Colonisation of antibiotic resistant bacteria in a cohort of HIV infected children in Ghana

PubMed Central

Sampane-Donkor, Eric; Badoe, Ebenezer Vincent; Annan, Jennifer Adoley; Nii-Trebi, Nicholas

2017-01-01

Antibiotic use not only selects for resistance in pathogenic bacteria, but also in commensal flora of exposed individuals. Little is known epidemiologically about antibiotic resistance in relation to people with HIV infection in sub-Saharan Africa. This study investigated the carriage of antibiotic resistant bacteria among HIV infected children at a tertiary hospital in Ghana. One hundred and eighteen HIV positive children were recruited at the Korle-Bu Teaching Hospital in Ghana and nasopharyngeal specimens were collected from them. The specimens were cultured for bacteria, and the isolates were identified by standard microbiological methods. Antibiotic susceptibility tests were carried out on selected bacterial organisms by the Kirby Bauer method. Bacteria isolated from the study subjects included Moraxella catarrhalis (39.8%), coagulase negative staphylococci (33.1%), Streptococcus pneumoniae (30.5%), diptheroids (29.7%), viridian streptococci (27.1%), Staphylococcus aureus (22.0%), Citrobacter spp. (4.2%) and Neisseria meningitidis (0.9%). Prevalence of antibiotic resistance of S. pneumoniae ranged from 5.6% (ceftriaxone) to 58.3% (cotrimoxazole), M. catarrhalis ranged from 2.1% (gentamicin) to 80.6% (ampicillin), and S. aureus ranged from 7.7% (cefoxitin) to 100% (penicillin). The prevalence of multiple drug resistance was 16.7% for S. pneumoniae, 57.4% for M. catarrhalis and 84.6% for S. aureus. HIV infected children in the study area commonly carry multi-drug resistant isolates of several pathogenic bacteria such as S. aureus and S. pneumoniae. Infections arising in these patients that are caused by S. aureus and S. pneumoniae could be treated with ceftriaxone and cefoxitin respectively. PMID:28451037

75 FR 52957 - Supplemental Funding Under the Food and Drug Administration's Food Emergency Response Laboratory...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-30

... enhance the lab capabilities to handle human pathogenic bacteria in animal feed. DATES: Important dates... supplemental grant funds will enable analyses of human pathogenic bacteria found in animal feed, for samples... bacteria in animal feed. This additional program will be compatible with other FERN Cooperative Agreement...

Synthetic analogs of bacterial quorum sensors

DOEpatents

Iyer, Rashi [Los Alamos, NM; Ganguly, Kumkum [Los Alamos, NM; Silks, Louis A [Los Alamos, NM

2011-12-06

Bacterial quorum-sensing molecule analogs having the following structures: ##STR00001## and methods of reducing bacterial pathogenicity, comprising providing a biological system comprising pathogenic bacteria which produce natural quorum-sensing molecule; providing a synthetic bacterial quorum-sensing molecule having the above structures and introducing the synthetic quorum-sensing molecule into the biological system comprising pathogenic bacteria. Further is provided a method of targeted delivery of an antibiotic, comprising providing a synthetic quorum-sensing molecule; chemically linking the synthetic quorum-sensing molecule to an antibiotic to produce a quorum-sensing molecule-antibiotic conjugate; and introducing the conjugate into a biological system comprising pathogenic bacteria susceptible to the antibiotic.

Synthetic analogs of bacterial quorum sensors

DOEpatents

Iyer, Rashi S.; Ganguly, Kumkum; Silks, Louis A.

2013-01-08

Bacterial quorum-sensing molecule analogs having the following structures: ##STR00001## and methods of reducing bacterial pathogenicity, comprising providing a biological system comprising pathogenic bacteria which produce natural quorum-sensing molecule; providing a synthetic bacterial quorum-sensing molecule having the above structures and introducing the synthetic quorum-sensing molecule into the biological system comprising pathogenic bacteria. Further is provided a method of targeted delivery of an antibiotic, comprising providing a synthetic quorum-sensing molecule; chemically linking the synthetic quorum-sensing molecule to an antibiotic to produce a quorum-sensing molecule-antibiotic conjugate; and introducing the conjugate into a biological system comprising pathogenic bacteria susceptible to the antibiotic.

How Bacterial Pathogens Eat Host Lipids: Implications for the Development of Fatty Acid Synthesis Therapeutics*

PubMed Central

Yao, Jiangwei; Rock, Charles O.

2015-01-01

Bacterial type II fatty acid synthesis (FASII) is a target for the development of novel therapeutics. Bacteria incorporate extracellular fatty acids into membrane lipids, raising the question of whether pathogens use host fatty acids to bypass FASII and defeat FASII therapeutics. Some pathogens suppress FASII when exogenous fatty acids are present to bypass FASII therapeutics. FASII inhibition cannot be bypassed in many bacteria because essential fatty acids cannot be obtained from the host. FASII antibiotics may not be effective against all bacteria, but a broad spectrum of Gram-negative and -positive pathogens can be effectively treated with FASII inhibitors. PMID:25648887

Silage review: Foodborne pathogens in silage and their mitigation by silage additives.

PubMed

Queiroz, O C M; Ogunade, I M; Weinberg, Z; Adesogan, A T

2018-05-01

Silage is one of the main ingredients in dairy cattle diets and it is an important source of nutrients, particularly energy and digestible fiber. Unlike properly made and managed silage, poorly made or contaminated silage can also be a source of pathogenic bacteria that may decrease dairy cow performance, reduce the safety and quality dairy products, and compromise animal and human health. Some of the pathogenic bacteria that are frequently or occasionally associated with silage are enterobacteria, Listeria, Bacillus spp., Clostridium spp., and Salmonella. The symptoms caused by these bacteria in dairy cows vary from mild diarrhea and reduced feed intake by Clostridium spp. to death and abortion by Listeria. Contamination of food products with pathogenic bacteria can cause losses of millions of dollars due to recalls of unsafe foods and decreases in the shelf life of dairy products. The presence of pathogenic bacteria in silage is usually due to contamination or poor management during the fermentation, aerobic exposure, or feed-out stages. Silage additives and inoculants can improve the safety of silage as well as the fermentation, nutrient recovery, quality, and shelf life. This review summarizes the literature on the main foodborne pathogens that occasionally infest silage and how additives can improve silage safety. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Prevalence of plant beneficial and human pathogenic bacteria isolated from salad vegetables in India.

PubMed

Nithya, Angamuthu; Babu, Subramanian

2017-03-14

The study aimed at enumerating, identifying and categorizing the endophytic cultivable bacterial community in selected salad vegetables (carrot, cucumber, tomato and onion). Vegetable samples were collected from markets of two vegetable hot spot growing areas, during two different crop harvest seasons. Crude and diluted vegetable extracts were plated and the population of endophytic bacteria was assessed based on morphologically distinguishable colonies. The bacterial isolates were identified by growth in selective media, biochemical tests and 16S rRNA gene sequencing. The endophytic population was found to be comparably higher in cucumber and tomato in both of the sampling locations, whereas lower in carrot and onion. Bacterial isolates belonged to 5 classes covering 46 distinct species belonging to 19 genera. Human opportunistic pathogens were predominant in carrot and onion, whereas plant beneficial bacteria dominated in cucumber and tomato. Out of the 104 isolates, 16.25% are human pathogens and 26.5% are human opportunistic pathogens. Existence of a high population of plant beneficial bacteria was found to have suppressed the population of plant and human pathogens. There is a greater potential to study the native endophytic plant beneficial bacteria for developing them as biocontrol agents against human pathogens that are harboured by plants.

Gram-Positive Uropathogens, Polymicrobial Urinary Tract Infection, and the Emerging Microbiota of the Urinary Tract

PubMed Central

Kline, Kimberly A.; Lewis, Amanda L.

2015-01-01

Gram-positive bacteria are a common cause of urinary tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI. Here we review the epidemiology, virulence mechanisms, and host response to the most frequently isolated Gram-positive uropathogens: Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae. We also review several emerging, rare, misclassified, and otherwise underreported Gram-positive pathogens of the urinary tract including Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella. The literature strongly suggests that urologic diseases involving Gram-positive bacteria may be easily overlooked due to limited culture-based assays typically utilized for urine in hospital microbiology laboratories. Some UTIs are polymicrobial in nature, often involving one or more Gram-positive bacteria. We herein review the risk factors and recent evidence for mechanisms of bacterial synergy in experimental models of polymicrobial UTI. Recent experimental data has demonstrated that, despite being cleared quickly from the bladder, some Gram-positive bacteria can impact pathogenic outcomes of co-infecting organisms. When taken together, the available evidence argues that Gram-positive bacteria are important uropathogens in their own right, but that some can be easily overlooked because they are missed by routine diagnostic methods. Finally, a growing body of evidence demonstrates that a surprising variety of fastidious Gram-positive bacteria may either reside in or be regularly exposed to the urinary tract and further suggests that their presence is widespread among women, as well as men. Experimental studies in this area are needed; however, there is a growing appreciation that the composition of bacteria found in the bladder could be a potentially important determinant in urologic disease, including susceptibility to UTI. PMID:27227294

Gram-Positive Uropathogens, Polymicrobial Urinary Tract Infection, and the Emerging Microbiota of the Urinary Tract.

PubMed

Kline, Kimberly A; Lewis, Amanda L

2016-04-01

Gram-positive bacteria are a common cause of urinary-tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI. Here we review the epidemiology, virulence mechanisms, and host response to the most frequently isolated Gram-positive uropathogens: Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae. We also review several emerging, rare, misclassified, and otherwise underreported Gram-positive pathogens of the urinary tract including Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella. The literature strongly suggests that urologic diseases involving Gram-positive bacteria may be easily overlooked due to limited culture-based assays typically utilized for urine in hospital microbiology laboratories. Some UTIs are polymicrobial in nature, often involving one or more Gram-positive bacteria. We herein review the risk factors and recent evidence for mechanisms of bacterial synergy in experimental models of polymicrobial UTI. Recent experimental data has demonstrated that, despite being cleared quickly from the bladder, some Gram-positive bacteria can impact pathogenic outcomes of co-infecting organisms. When taken together, the available evidence argues that Gram-positive bacteria are important uropathogens in their own right, but that some can be easily overlooked because they are missed by routine diagnostic methods. Finally, a growing body of evidence demonstrates that a surprising variety of fastidious Gram-positive bacteria may either reside in or be regularly exposed to the urinary tract and further suggests that their presence is widespread among women, as well as men. Experimental studies in this area are needed; however, there is a growing appreciation that the composition of bacteria found in the bladder could be a potentially important determinant in urologic disease, including susceptibility to UTI.

Number of viable bacteria and presumptive antibiotic residues in milk fed to calves on commercial dairies.

PubMed

Selim, S A; Cullor, J S

1997-10-15

To assess the number of bacteria and presumptive antibiotic residues in milk fed to calves and to identify those bacteria and the antibiotic susceptibility of selected bacterial strains. Cross-sectional prospective study. 189 samples obtained from 12 local dairies. Samples of waste milk and milk-based fluids (eg, milk replacer, colostrum, bulk-tank milk) were obtained. Cumulative number of viable bacteria was determined. Bacteria were cultured aerobically, and antibiotic susceptibility testing of selected strains was performed. Presumptive antibiotic residues were detected by use of test kits. Geometric mean of the cumulative number of bacteria for waste milk samples was significantly higher than for other types of milk or milk-based products. Streptococcus sp (84/165 samples) and Enterobacteriaceae (83/165 samples) were the predominant bacteria identified, followed by Staphylococcus sp (68/165 samples). Escherichia coli was the gram-negative species most commonly isolated (52/165 samples; 32%); however, none were strain O157. Salmonella sp or Mycoplasma sp were not isolated. Of 189 samples, 119 (63%) were positive when tested for beta-lactams or tetracycline by use of 2 commercially available assays. In vitro, some bacteria were resistant to commonly used antibiotics. Waste milk that has not been effectively treated (eg, pasteurization) to reduce microbial load prior to use as calf feed should be used with caution, because it may contain a high number of bacteria that may be pathogenic to cattle and human beings. Antibiotic residues that would constitute violative amounts and existence of multiple antibiotic resistant bacterial strains are concerns in calf health management and dairy food safety.

Rapid detection of bacteria with miniaturized pyrolysis-gas chromatographic analysis

NASA Astrophysics Data System (ADS)

Mowry, Curtis; Morgan, Catherine H.; Baca, Quentin; Manginell, Ronald P.; Kottenstette, Richard J.; Lewis, Patrick; Frye-Mason, Gregory C.

2002-02-01

Rapid detection and identification of bacteria and other pathogens is important for many civilian and military applications. The profiles of biological markers such as fatty acids can be used to characterize biological samples or to distinguish bacteria at the gram-type, genera, and even species level. Common methods for whole cell bacterial analysis are neither portable nor rapid, requiring lengthy, labor intensive sample preparation and bench-scale instrumentation. These methods chemically derivatize fatty acids to produce more volatile fatty acid methyl esters (FAMEs) that can be separated and analyzed by a gas chromatograph (GC)/mass spectrometer. More recent publications demonstrate decreased sample preparation time with in situ derivatization of whole bacterial samples using pyrolysis/derivatization. Ongoing development of miniaturized pyrolysis/GC instrumentation by this department capitalizes on Sandia advances in the field of microfabricated chemical analysis systems ((mu) ChemLab). Microdevices include rapidly heated stages capable of pyrolysis or sample concentration, gas chromatography columns, and surface acoustic wave (SAW) sensor arrays. We will present results demonstrating the capabilities of these devices toward fulfilling the goal of portable, rapid detection and early warning of the presence of pathogens in air or water.

Behavior of pathogenic bacteria in the oyster, Crassostrea commercialis, during depuration, re-laying, and storage.

PubMed Central

Son, N T; Fleet, G H

1980-01-01

Oysters (Crassostrea commercials) harvested from major cultivation areas within the state of New South Wales, Australia, were commonly contaminated with low levels of the food-poisoning organisms Bacillus cereus, Clostridium perfringens, and Vibrio parahaemolyticus. Salmonella was found in oysters on only one occasion. These bacteria were cleansed from oysters during oyster purification by re-laying in a non-polluted waterway. Oysters were laboratory contaminated to levels in excess 1,000 cells per g with either B. cereus, C. perfringens, V. parahaemolyticus, Salmonella typhimurium, or S. senftenberg. These species were cleansed from such oysters during purification in a laboratory depuration unit that used ultraviolet light for sterilizing the depuration water. Escherichia coli was also cleansed from oysters under the same re-laying or depuration conditions so that its measurement alone could be used to indicate the cleansing of the above pathogenic species. The levels of these bacteria were also measured during the storage of oysters under conditions that occur during marketing. While B. cereus counts remained relatively stable during storage, the Salmonella spp. gradually decreased in numbers and C. perfringens rapidly died off. V. parahaemolyticus counts increased slightly during the first 4 days of storage, after which decreases occurred. PMID:6257164

Behavior of pathogenic bacteria in the oyster, Crassostrea commercialis, during depuration, re-laying, and storage.

PubMed

Son, N T; Fleet, G H

1980-12-01

Oysters (Crassostrea commercials) harvested from major cultivation areas within the state of New South Wales, Australia, were commonly contaminated with low levels of the food-poisoning organisms Bacillus cereus, Clostridium perfringens, and Vibrio parahaemolyticus. Salmonella was found in oysters on only one occasion. These bacteria were cleansed from oysters during oyster purification by re-laying in a non-polluted waterway. Oysters were laboratory contaminated to levels in excess 1,000 cells per g with either B. cereus, C. perfringens, V. parahaemolyticus, Salmonella typhimurium, or S. senftenberg. These species were cleansed from such oysters during purification in a laboratory depuration unit that used ultraviolet light for sterilizing the depuration water. Escherichia coli was also cleansed from oysters under the same re-laying or depuration conditions so that its measurement alone could be used to indicate the cleansing of the above pathogenic species. The levels of these bacteria were also measured during the storage of oysters under conditions that occur during marketing. While B. cereus counts remained relatively stable during storage, the Salmonella spp. gradually decreased in numbers and C. perfringens rapidly died off. V. parahaemolyticus counts increased slightly during the first 4 days of storage, after which decreases occurred.

A retrospective audit of bacterial culture results of donated human milk in Perth, Western Australia.

PubMed

Almutawif, Yahya; Hartmann, Benjamin; Lloyd, Megan; Erber, Wendy; Geddes, Donna

2017-02-01

The bacterial content of donated human milk is either endogenous or introduced via contamination. Defining milk bank bacterial content will allow researchers to devise appropriate tests for significant and commonly encountered organisms. A retrospective audit was conducted on data recorded from the Perron Rotary Express Milk Bank, King Edward Memorial Hospital, Subiaco, Western Australia. This aimed to describe the incidence of bacterial species detected in donated human milk and to identify potentially pathogenic bacteria. The data comprised of 2890 batches donated by 448 women between 2007 and 2011. Coagulase negative Staphylococcus (CoNS) represented the highest prevalence of bacteria in donated milk, isolated from 85.5% of batches (range: 20 to 650,000CFU/mL) followed by Acinetobacter species in 8.1% of batches (range: 100 to 180,000CFU/mL). Staphylococcus aureus was the most prevalent potentially pathogenic bacteria in 5% of batches (range: 40 to 100,000CFU/mL). Further investigation is warranted to better define the risks posed by the presence of toxin-producing S. aureus in raw and pasteurized human milk which may allow minimization of risk to the preterm infants. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Comparative Genomics Evidence That Only Protein Toxins are Tagging Bad Bugs

PubMed Central

Georgiades, Kalliopi; Raoult, Didier

2011-01-01

The term toxin was introduced by Roux and Yersin and describes macromolecular substances that, when produced during infection or when introduced parenterally or orally, cause an impairment of physiological functions that lead to disease or to the death of the infected organism. Long after the discovery of toxins, early genetic studies on bacterial virulence demonstrated that removing a certain number of genes from pathogenic bacteria decreases their capacity to infect hosts. Each of the removed factors was therefore referred to as a “virulence factor,” and it was speculated that non-pathogenic bacteria lack such supplementary factors. However, many recent comparative studies demonstrate that the specialization of bacteria to eukaryotic hosts is associated with massive gene loss. We recently demonstrated that the only features that seem to characterize 12 epidemic bacteria are toxin–antitoxin (TA) modules, which are addiction molecules in host bacteria. In this study, we investigated if protein toxins are indeed the only molecules specific to pathogenic bacteria by comparing 14 epidemic bacterial killers (“bad bugs”) with their 14 closest non-epidemic relatives (“controls”). We found protein toxins in significantly more elevated numbers in all of the “bad bugs.” For the first time, statistical principal components analysis, including genome size, GC%, TA modules, restriction enzymes, and toxins, revealed that toxins are the only proteins other than TA modules that are correlated with the pathogenic character of bacteria. Moreover, intracellular toxins appear to be more correlated with the pathogenic character of bacteria than secreted toxins. In conclusion, we hypothesize that the only truly identifiable phenomena, witnessing the convergent evolution of the most pathogenic bacteria for humans are the loss of metabolic activities, i.e., the outcome of the loss of regulatory and transcription factors and the presence of protein toxins, alone, or coupled as TA modules. PMID:22919573

Food provisioning alters infection dynamics in populations of a wild rodent

PubMed Central

Forbes, Kristian M.; Henttonen, Heikki; Hirvelä-Koski, Varpu; Kipar, Anja; Mappes, Tapio; Stuart, Peter; Huitu, Otso

2015-01-01

While pathogens are often assumed to limit the growth of wildlife populations, experimental evidence for their effects is rare. A lack of food resources has been suggested to enhance the negative effects of pathogen infection on host populations, but this theory has received little investigation. We conducted a replicated two-factor enclosure experiment, with introduction of the bacterium Bordetella bronchiseptica and food supplementation, to evaluate the individual and interactive effects of pathogen infection and food availability on vole populations during a boreal winter. We show that prior to bacteria introduction, vole populations were limited by food availability. Bordetella bronchiseptica introduction then reduced population growth and abundance, but contrary to predictions, primarily in food supplemented populations. Infection prevalence and pathological changes in vole lungs were most common in food supplemented populations, and are likely to have resulted from increased congregation and bacteria transmission around feeding stations. Bordetella bronchiseptica-infected lungs often showed protozoan co-infection (consistent with Hepatozoon erhardovae), together with more severe inflammatory changes. Using a multidisciplinary approach, this study demonstrates a complex picture of interactions and underlying mechanisms, leading to population-level effects. Our results highlight the potential for food provisioning to markedly influence disease processes in wildlife mammal populations. PMID:26446813

Mycobacteria in Finnish cooling tower waters.

PubMed

Torvinen, Eila; Suomalainen, Sini; Paulin, Lars; Kusnetsov, Jaana

2014-04-01

Evaporative cooling towers are water systems used in, e.g., industry and telecommunication to remove excess heat by evaporation of water. Temperatures of cooling waters are usually optimal for mesophilic microbial growth and cooling towers may liberate massive amounts of bacterial aerosols. Outbreaks of legionellosis associated with cooling towers have been known since the 1980's, but occurrences of other potentially pathogenic bacteria in cooling waters are mostly unknown. We examined the occurrence of mycobacteria, which are common bacteria in different water systems and may cause pulmonary and other soft tissue infections, in cooling waters containing different numbers of legionellae. Mycobacteria were isolated from all twelve cooling systems and from 92% of the 24 samples studied. Their numbers in the positive samples varied from 10 to 7.3 × 10(4) cfu/L. The isolated species included M. chelonae/abscessus, M. fortuitum, M. mucogenicum, M. peregrinum, M. intracellulare, M. lentiflavum, M. avium/nebraskense/scrofulaceum and many non-pathogenic species. The numbers of mycobacteria correlated negatively with the numbers of legionellae and the concentration of copper. The results show that cooling towers are suitable environments for potentially pathogenic mycobacteria. Further transmission of mycobacteria from the towers to the environment needs examination. © 2013 APMIS. Published by John Wiley & Sons Ltd.

MinION Nanopore Sequencing Enables Correlation between Resistome Phenotype and Genotype of Coliform Bacteria in Municipal Sewage.

PubMed

Xia, Yu; Li, An-Dong; Deng, Yu; Jiang, Xiao-Tao; Li, Li-Guan; Zhang, Tong

2017-01-01

Wastewater treatment plants (WWTPs) functioned as the intersection between the human society and nature environment, are receiving increasingly more attention on risk assessment of the acquisition of environmental antibiotic resistance genes (ARGs) by pathogenetic populations during treatment. However, because of the general lack of robust resistome profiling methods, genotype, and resistance phenotype is still poorly correlated in human pathogens of sewage samples. Here we applied MinION sequencing to quantify the resistance genes of multiple antibiotic resistant (MAR) coliform bacteria, a common indicator for human enteric pathogens in sewage samples. Our pipeline could deliver the results within 30 h from sample collection and the resistome quantification was consistent to that based on the Illumina platform. Additionally, the long nanopore reads not only enabled a simultaneous identification of the carrier populations of ARGs detected, but also facilitated the genome reconstruction of a representative MAR strain, from which we identified an instance of chromosomal integration of environmental resistance gene obtained by plasmid exchange with a porcine pathogen. This study demonstrated the utilization of MinION sequencing in quick monitoring and simultaneous phylogenetic tracking of environmental ARGs to address potential health risk associated with them.

MinION Nanopore Sequencing Enables Correlation between Resistome Phenotype and Genotype of Coliform Bacteria in Municipal Sewage

PubMed Central

Xia, Yu; Li, An-Dong; Deng, Yu; Jiang, Xiao-Tao; Li, Li-Guan; Zhang, Tong

2017-01-01

Wastewater treatment plants (WWTPs) functioned as the intersection between the human society and nature environment, are receiving increasingly more attention on risk assessment of the acquisition of environmental antibiotic resistance genes (ARGs) by pathogenetic populations during treatment. However, because of the general lack of robust resistome profiling methods, genotype, and resistance phenotype is still poorly correlated in human pathogens of sewage samples. Here we applied MinION sequencing to quantify the resistance genes of multiple antibiotic resistant (MAR) coliform bacteria, a common indicator for human enteric pathogens in sewage samples. Our pipeline could deliver the results within 30 h from sample collection and the resistome quantification was consistent to that based on the Illumina platform. Additionally, the long nanopore reads not only enabled a simultaneous identification of the carrier populations of ARGs detected, but also facilitated the genome reconstruction of a representative MAR strain, from which we identified an instance of chromosomal integration of environmental resistance gene obtained by plasmid exchange with a porcine pathogen. This study demonstrated the utilization of MinION sequencing in quick monitoring and simultaneous phylogenetic tracking of environmental ARGs to address potential health risk associated with them. PMID:29163399

Bacterial community structure in experimental methanogenic bioreactors and search for pathogenic clostridia as community members.

PubMed

Dohrmann, Anja B; Baumert, Susann; Klingebiel, Lars; Weiland, Peter; Tebbe, Christoph C

2011-03-01

Microbial conversion of organic waste or harvested plant material into biogas has become an attractive technology for energy production. Biogas is produced in reactors under anaerobic conditions by a consortium of microorganisms which commonly include bacteria of the genus Clostridium. Since the genus Clostridium also harbors some highly pathogenic members in its phylogenetic cluster I, there has been some concern that an unintended growth of such pathogens might occur during the fermentation process. Therefore this study aimed to follow how process parameters affect the diversity of Bacteria in general, and the diversity of Clostridium cluster I members in particular. The development of both communities was followed in model biogas reactors from start-up during stable methanogenic conditions. The biogas reactors were run with either cattle or pig manures as substrates, and both were operated at mesophilic and thermophilic conditions. The structural diversity was analyzed independent of cultivation using a PCR-based detection of 16S rRNA genes and genetic profiling by single-strand conformation polymorphism (SSCP). Genetic profiles indicated that both bacterial and clostridial communities evolved in parallel, and the community structures were highly influenced by both substrate and temperature. Sequence analysis of 16S rRNA genes recovered from prominent bands from SSCP profiles representing Clostridia detected no pathogenic species. Thus, this study gave no indication that pathogenic clostridia would be enriched as dominant community members in biogas reactors fed with manure.

Pathogenic bacteria and microbial-source tracking markers in Brandywine Creek Basin, Pennsylvania and Delaware, 2009-10

USGS Publications Warehouse

Duris, Joseph W.; Reif, Andrew G.; Olson, Leif E.; Johnson, Heather E.

2011-01-01

The City of Wilmington, Delaware, is in the downstream part of the Brandywine Creek Basin, on the main stem of Brandywine Creek. Wilmington uses this stream, which drains a mixed-land-use area upstream, for its main drinking-water supply. Because the stream is used for drinking water, Wilmington is in need of information about the occurrence and distribution of specific fecally derived pathogenic bacteria (disease-causing bacteria) and their relations to commonly measured fecal-indicator bacteria (FIB), as well as information regarding the potential sources of the fecal pollution and pathogens in the basin. This study focused on five routinely sampled sites within the basin, one each on the West Branch and the East Branch of Brandywine Creek and at three on the main stem below the confluence of the West and East Branches. These sites were sampled monthly for 1 year. Targeted event samples were collected on two occasions during high flow and two occasions during normal flow. On the basis of this study, high flows in the Brandywine Creek Basin were related to increases in FIB densities, and in the frequency of selected pathogen and source markers, in the West Branch and main stem of Brandywine Creek, but not in the East Branch. Water exceeding the moderate fullbody-contact single-sample recreational water-quality criteria (RWQC) for Escherichia coli (E. coli) was more likely to contain selected markers for pathogenic E. coli (eaeA,stx1, and rfbO157 gene markers) and bovine fecal sources (E. hirae and LTIIa gene markers), whereas samples exceeding the enterococci RWQC were more likely to contain the same pathogenic markers but also were more likely to carry a marker indicative of human source (esp gene marker). On four sample dates, during high flow between October and March, the West Branch was the only observed potential contributor of selected pathogen and bovine source markers to the main stem of Brandywine Creek. Indeed, the stx2 marker, which indicates a highly virulent type of pathogenic E. coli, was found only in the West Branch and main stem at high flow but was not found in the East Branch under similar conditions. However, it must be noted that throughout the entire year of sampling there were occasions, during both high and normal flows, when both the East and West Branches were potential contributors of pathogen and microbial-source tracking markers to the main stem. Therefore, this study indicates that under selected conditions (high flow, October through March), West Branch Brandywine Creek Basin was the most likely source of elevated FIB densities in the main stem. These elevated densities are associated with more frequent detection of selected pathogenic E. coli markers (rfbO157 stx1) and are associated with MST markers of bovine source. However, during other times of the year, both the West Branch and East Branch Basins are acting as potential sources of FIB and fecally derived pathogens.

NORMAL FLORA OF THE NOSE, THROAT, AND LOWER INTESTINE OF DOGS

PubMed Central

Clapper, W. E.; Meade, G. H.

1963-01-01

Clapper, W. E. (The Lovelace Foundation for Medical Education and Research, Albuquerque, N.M.) and G. H. Meade. Normal flora of the nose, throat, and lower intestine of dogs. J. Bacteriol. 85:643–648. 1963.—An attempt was made to isolate and identify the complete normal flora of the rectum, nose, and throat of beagles. For primary isolation, 12 different kinds of media were used. Incubation of blood agar plates and slants anaerobically, and of thioglycolate broth aerobically, allowed the growth of obligate anaerobes. From the rectal specimens, 20 species of bacteria and 10 species of fungi were isolated and identified. The organisms were similar to those found in the human intestine. Escherichia coli, Streptococcus mitis, enterococci, S. lactis, Bacillus species, and coliforms other than E. coli were most frequently encountered. The frequency of occurrence was approximately the same at both samplings in more commonly cultured bacteria. Pathogenic E. coli were isolated from nearly one-third of the first specimens. These were the only human pathogens observed. In the throat cultures, 29 species of bacteria and 2 species of yeasts were identified, and 27 species of bacteria were identified from the nasal cultures. S. mitis, Neisseria, and coagulase-negative Staphylococcus were most often isolated. The flora was similar to that found in human nose and throat cultures, except that more Haemophilus and pneumococcus and fewer coliforms are generally found in human throats. Organisms resembling human pathogens were group A streptococci and coagulase-positive staphylococci. These were isolated infrequently. It appears that this kind of examination would reveal any significant changes in normal flora that might be related to the health of the animal. PMID:14042944

Fluorescence spectroscopy for rapid detection and classification of bacterial pathogens.

PubMed

Sohn, Miryeong; Himmelsbach, David S; Barton, Franklin E; Fedorka-Cray, Paula J

2009-11-01

This study deals with the rapid detection and differentiation of Escherichia coli, Salmonella, and Campylobacter, which are the most commonly identified commensal and pathogenic bacteria in foods, using fluorescence spectroscopy and multivariate analysis. Each bacterial sample cultured under controlled conditions was diluted in physiologic saline for analysis. Fluorescence spectra were collected over a range of 200-700 nm with 0.5 nm intervals on the PerkinElmer Fluorescence Spectrometer. The synchronous scan technique was employed to find the optimum excitation (lambda(ex)) and emission (lambda(em)) wavelengths for individual bacteria with the wavelength interval (Deltalambda) being varied from 10 to 200 nm. The synchronous spectra and two-dimensional plots showed two maximum lambda(ex) values at 225 nm and 280 nm and one maximum lambda(em) at 335-345 nm (lambda(em) = lambda(ex) + Deltalambda), which correspond to the lambda(ex) = 225 nm, Deltalambda = 110-120 nm, and lambda(ex) = 280 nm, Deltalambda = 60-65 nm. For all three bacterial genera, the same synchronous scan results were obtained. The emission spectra from the three bacteria groups were very similar, creating difficulty in classification. However, the application of principal component analysis (PCA) to the fluorescence spectra resulted in successful classification of the bacteria by their genus as well as determining their concentration. The detection limit was approximately 10(3)-10(4) cells/mL for each bacterial sample. These results demonstrated that fluorescence spectroscopy, when coupled with PCA processing, has the potential to detect and to classify bacterial pathogens in liquids. The methodology is rapid (>10 min), inexpensive, and requires minimal sample preparation compared to standard analytical methods for bacterial detection.

Carriage by the housefly (Musca domestica) of multiple-antibiotic-resistant bacteria that are potentially pathogenic to humans, in hospital and other urban environments in Misurata, Libya.

PubMed

Rahuma, N; Ghenghesh, K S; Ben Aissa, R; Elamaari, A

2005-12-01

Using standard microbiological procedures, bacteria that are potentially pathogenic to humans were isolated from 150 houseflies collected in the Libyan city of Misurata (50 flies each from the Central Hospital, streets and abattoir). Salmonella spp., Yersinia enterocolitica and Edwardsiella tarda were isolated from flies collected on the streets and in the abattoir but not from those collected in the hospital. Shigella sonnei was detected in just one fly, which was collected in the abattoir. Of the flies collected in the hospital, streets and abattor, 42%, 42% and 32% were positive for Escherichia coli, 70%, 50% and 62% for Klebsiella spp., 2%, 20% and 10% for Aeromonas spp., 96%, 36% and 34% for Pseudomonas spp., 20%, 12% and 16% for Staphylococcus spp., and 24%, 22% and 18% for Streptococcus spp., respectively. When the antibiotic susceptibilities of the fly isolates were investigated, the Enterobacteria isolated from the houseflies collected in the hospital were found to be resistant to significantly more of the commonly used antibiotics that were tested than the Enterobacteria isolated from the flies caught in the streets or abattoir. Whatever the source of the flies from which they were collected, the Pseudomonas isolates frequently showed resistance to multiple antibiotics, with >50% each being resistant to at least 10 antimicrobial agents. Two isolates of Sta. aureus (both from flies collected in the hospital) were resistant to methicillin. The present study supports the belief that the housefly is a potential vector of multiple-antibiotic-resistant, pathogenic bacteria, including methicillin-resistant Sta. aureus, in the hospital environment. Given their mobility, it seems likely that houseflies carry such pathogens from hospitals to surrounding communities, and vice versa.

Proteomic and metabolomic responses in hepatopancreas of Mytilus galloprovincialis challenged by Micrococcus luteus and Vibrio anguillarum.

PubMed

Wu, Huifeng; Ji, Chenglong; Wei, Lei; Zhao, Jianmin; Lu, Hongjian

2013-12-06

The outbreak of pathogens can induce diseases and lead to massive mortalities of aquaculture animals including fish, mollusk and shrimp. In this work, the responses induced by Micrococcus luteus and Vibrio anguillarum were investigated in hepatopancreas of mussel Mytilus galloprovincialis using proteomics and metabolomics. Metabolic biomarkers demonstrated that M. luteus and V. anguillarum injections could induce osmotic stress and disturbance in energy metabolism. And the uniquely and more markedly altered metabolic biomarkers (glutamine, succinate, aspartate, glucose, ATP, homarine and tyrosine) indicated that V. anguillarum could cause more severe disturbances in osmotic regulation and energy metabolism. The differentially altered proteins meant that M. luteus and V. anguillarum induced different effects in mussels. However, the common proteomic biomarkers, arginine kinase and small heat shock protein, demonstrated that these two bacteria induced similar effects including oxidative stress and disturbance in energy metabolism in M. galloprovincialis. In addition, some metabolic biomarkers, ATP and glutamine, were confirmed by related proteins including arginine kinase, ATP synthase, nucleoside diphosphate kinase and glutamine synthetase in bacteria-challenged mussels. This study demonstrated that proteomics and metabolomics could provide an insightful view into the effects of environmental pathogens to the marine mussel M. galloprovincialis. The outbreak of pathogens can lead to diseases and massive mortalities of aquaculture animals including fish, mollusk and shrimp. The mussel M. galloprovincialis distributes widely along the Bohai coast and is popularly consumed as delicious seafood by local residents. This bivalve has become one of the important species in marine aquaculture industry in China. Therefore a study on pathogen-induced effects is necessary. In the present study, an integrated metabolomic and proteomic approach was used to elucidate the differential effects induced by the representative Gram-positive (M. luteus) and Gram-negative (V. anguillarum) bacteria in M. galloprovincialis. © 2013.

Natural soil reservoirs for human pathogenic and fecal indicator bacteria

USGS Publications Warehouse

Boschiroli, Maria L; Falkinham, Joseph; Favre-Bonte, Sabine; Nazaret, Sylvie; Piveteau, Pascal; Sadowsky, Michael J.; Byappanahalli, Muruleedhara; Delaquis, Pascal; Hartmann, Alain

2016-01-01

Soils receive inputs of human pathogenic and indicator bacteria through land application of animal manures or sewage sludge, and inputs by wildlife. Soil is an extremely heterogeneous substrate and contains meso- and macrofauna that may be reservoirs for bacteria of human health concern. The ability to detect and quantify bacteria of human health concern is important in risk assessments and in evaluating the efficacy of agricultural soil management practices that are protective of crop quality and protective of adjacent water resources. The present chapter describes the distribution of selected Gram-positive and Gram-negative bacteria in soils. Methods for detecting and quantifying soilborne bacteria including extraction, enrichment using immunomagnetic capture, culturing, molecular detection and deep sequencing of metagenomic DNA to detect pathogens are overviewed. Methods for strain phenotypic and genotypic characterization are presented, as well as how comparison with clinical isolates can inform the potential for human health risk.

Detection of pathogenic gram negative bacteria using infrared thermography

NASA Astrophysics Data System (ADS)

Lahiri, B. B.; Divya, M. P.; Bagavathiappan, S.; Thomas, Sabu; Philip, John

2012-11-01

Detection of viable bacteria is of prime importance in all fields of microbiology and biotechnology. Conventional methods of enumerating bacteria are often time consuming and labor-intensive. All living organisms generate heat due to metabolic activities and hence, measurement of heat energy is a viable tool for detection and quantification of bacteria. In this article, we employ a non-contact and real time method - infrared thermography (IRT) for measurement of temperature variations in four clinically significant gram negative pathogenic bacteria, viz. Vibrio cholerae, Vibrio mimicus, Proteus mirabilis and Pseudomonas aeruginosa. We observe that, the energy content, defined as the ratio of heat generated by bacterial metabolic activities to the heat lost from the liquid medium to the surrounding, vary linearly with the bacterial concentration in all the four pathogenic bacteria. The amount of energy content observed in different species is attributed to their metabolisms and morphologies that affect the convection velocity and hence heat transport in the medium.

Design and Construction of a Single-Tube, LATE-PCR, Multiplex Endpoint Assay with Lights-On/Lights-Off Probes for the Detection of Pathogens Associated with Sepsis

PubMed Central

Carver-Brown, Rachel K.; Reis, Arthur H.; Rice, Lisa M.; Czajka, John W.; Wangh, Lawrence J.

2012-01-01

Aims. The goal of this study was to construct a single tube molecular diagnostic multiplex assay for the detection of microbial pathogens commonly associated with septicemia, using LATE-PCR and Lights-On/Lights-Off probe technology. Methods and Results. The assay described here identified pathogens associated with sepsis by amplification and analysis of the 16S ribosomal DNA gene sequence for bacteria and specific gene sequences for fungi. A sequence from an unidentified gene in Lactococcus lactis subsp. cremoris served as a positive control for assay function. LATE-PCR was used to generate single-stranded amplicons that were then analyzed at endpoint over a wide temperature range in a specific fluorescent color. Each bacterial target was identified by its pattern of hybridization to Lights-On/Lights-Off probes derived from molecular beacons. Complex mixtures of targets were also detected. Conclusions. All microbial targets were identified in samples containing low starting copy numbers of pathogen genomic DNA, both as individual targets and in complex mixtures. Significance and Impact of the Study. This assay uses new technology to achieve an advance in the field of molecular diagnostics: a single-tube multiplex assay for identification of pathogens commonly associated with sepsis. PMID:23326668

Detection of rotavirus and other enteropathogens in children hospitalized with acute gastroenteritis in Havana, Cuba.

PubMed

Ribas, María de Los Angeles; Tejero, Yahisel; Cordero, Yanislet; de Los Angeles León, María; Rodriguez, Misladys; Perez-Lastre, Jorge; Triana, Thelma; Guerra, Mabel; Ayllón, Lucía; Escalante, Gladys; Hadad, Jorge

2015-08-01

The aim of the study was to diagnose infections with rotavirus and other enteric pathogens in children under five years old with acute gastroenteritis and to identify the most common epidemiological and clinical characteristics of these pathogens. The study was conducted using 110 stool samples from the same number of children under five years old who were inpatients at three paediatric hospitals in Havana, Cuba, between October and December 2011. The samples were tested for rotavirus and other enteric pathogens using traditional and molecular microbiological methods. Pathogens were detected in 85 (77.3 %) of the children. Rotavirus was the most commonly found, appearing in 54.5 % of the children, followed by bacteria (29 %) and parasites (10.9 %). Other viral pathogens detected included adenovirus (6.4 %) and astrovirus (3.6 %). In rotavirus-positives cases, at least one other pathogen was detected, usually a bacterium (26.6 %). More than three episodes of watery diarrhea in 24 hours were observed in 78.3 % of the cases. Dehydration was found in 30 (50 %) rotavirus-positive children, of whom seven (11.6 %) were transferred to an intensive care unit due to complications of metabolic acidosis. Rotavirus was most commonly observed among children under 12 months old (65 %). The highest incidence of infection occurred in children who were under the care of a relative at home (78.3 %), had not been breastfed (65 %), or had been breastfed for less than six months (28.3 %). The genotype combinations most frequently found were G9P8 (28.3 %) and G1P8 (10 %). This study demonstrates the presence of rotavirus and other enteric pathogens as causes of gastroenteritis in hospitalized infants and young children in Cuba.

'Add, stir and reduce': Yersinia spp. as model bacteria for pathogen evolution.

PubMed

McNally, Alan; Thomson, Nicholas R; Reuter, Sandra; Wren, Brendan W

2016-03-01

Pathogenic species in the Yersinia genus have historically been targets for research aimed at understanding how bacteria evolve into mammalian pathogens. The advent of large-scale population genomic studies has greatly accelerated the progress in this field, and Yersinia pestis, Yersinia pseudotuberculosis and Yersinia enterocolitica have once again acted as model organisms to help shape our understanding of the evolutionary processes involved in pathogenesis. In this Review, we highlight the gene gain, gene loss and genome rearrangement events that have been identified by genomic studies in pathogenic Yersinia species, and we discuss how these findings are changing our understanding of pathogen evolution. Finally, as these traits are also found in the genomes of other species in the Enterobacteriaceae, we suggest that they provide a blueprint for the evolution of enteropathogenic bacteria.

Genome dynamics and its impact on evolution of Escherichia coli.

PubMed

Dobrindt, Ulrich; Chowdary, M Geddam; Krumbholz, G; Hacker, J

2010-08-01

The Escherichia coli genome consists of a conserved part, the so-called core genome, which encodes essential cellular functions and of a flexible, strain-specific part. Genes that belong to the flexible genome code for factors involved in bacterial fitness and adaptation to different environments. Adaptation includes increase in fitness and colonization capacity. Pathogenic as well as non-pathogenic bacteria carry mobile and accessory genetic elements such as plasmids, bacteriophages, genomic islands and others, which code for functions required for proper adaptation. Escherichia coli is a very good example to study the interdependency of genome architecture and lifestyle of bacteria. Thus, these species include pathogenic variants as well as commensal bacteria adapted to different host organisms. In Escherichia coli, various genetic elements encode for pathogenicity factors as well as factors, which increase the fitness of non-pathogenic bacteria. The processes of genome dynamics, such as gene transfer, genome reduction, rearrangements as well as point mutations contribute to the adaptation of the bacteria into particular environments. Using Escherichia coli model organisms, such as uropathogenic strain 536 or commensal strain Nissle 1917, we studied mechanisms of genome dynamics and discuss these processes in the light of the evolution of microbes.

Pathogenic features of heterotrophic plate count bacteria from drinking-water boreholes.

PubMed

Horn, Suranie; Pieters, Rialet; Bezuidenhout, Carlos

2016-12-01

Evidence suggests that heterotrophic plate count (HPC) bacteria may be hazardous to humans with weakened health. We investigated the pathogenic potential of HPC bacteria from untreated borehole water, consumed by humans, for: their haemolytic properties, the production of extracellular enzymes such as DNase, proteinase, lipase, lecithinase, hyaluronidase and chondroitinase, the effect simulated gastric fluid has on their survival, as well as the bacteria's antibiotic-susceptible profile. HuTu-80 cells acted as model for the human intestine and were exposed to the HPC isolates to determine their effects on the viability of the cells. Several HPC isolates were α- or β-haemolytic, produced two or more extracellular enzymes, survived the SGF treatment, and showed resistance against selected antibiotics. The isolates were also harmful to the human intestinal cells to varying degrees. A novel pathogen score was calculated for each isolate. Bacillus cereus had the highest pathogen index: the pathogenicity of the other bacteria declined as follows: Aeromonas taiwanensis > Aeromonas hydrophila > Bacillus thuringiensis > Alcaligenes faecalis > Pseudomonas sp. > Bacillus pumilus > Brevibacillus sp. > Bacillus subtilis > Bacillus sp. These results demonstrated that the prevailing standards for HPCs in drinking water may expose humans with compromised immune systems to undue risk.

Network Analysis Highlights Complex Interactions between Pathogen, Host and Commensal Microbiota

PubMed Central

Boutin, Sébastien; Bernatchez, Louis; Audet, Céline; Derôme, Nicolas

2013-01-01

Interactions between bacteria and their host represent a full continuum from pathogenicity to mutualism. From an evolutionary perspective, host-bacteria relationships are no longer considered a two-component system but rather a complex network. In this study, we focused on the relationship between brook charr (Salvelinus fontinalis) and bacterial communities developing on skin mucus. We hypothesized that stressful conditions such as those occurring in aquaculture production induce shifts in the bacterial community of healthy fish, thus allowing pathogens to cause infections. The results showed that fish skin mucus microbiota taxonomical structure is highly specific, its diversity being partly influenced by the surrounding water bacterial community. Two types of taxonomic co-variation patterns emerged across 121 contrasted communities’ samples: one encompassing four genera well known for their probiotic properties, the other harboring five genera mostly associated with pathogen species. The homeostasis of fish bacterial community was extensively disturbed by induction of physiological stress in that both: 1) the abundance of probiotic-like bacteria decreased after stress exposure; and 2) pathogenic bacteria increased following stress exposure. This study provides further insights regarding the role of mutualistic bacteria as a primary host protection barrier. PMID:24376845

Broad activity of diphenyleneiodonium analogues against Mycobacterium tuberculosis, malaria parasites and bacterial pathogens.

PubMed

Nguyen, Nghi; Wilson, Danny W; Nagalingam, Gayathri; Triccas, James A; Schneider, Elena K; Li, Jian; Velkov, Tony; Baell, Jonathan

2018-03-25

In this study, a structure-activity relationship (SAR) compound series based on the NDH-2 inhibitor diphenyleneiodonium (DPI) was synthesised. Compounds were evaluated primarily for in vitro efficacy against Gram-positive and Gram-negative bacteria, commonly responsible for nosocomial and community acquired infections. In addition, we also assessed the activity of these compounds against Mycobacterium tuberculosis (Tuberculosis) and Plasmodium spp. (Malaria). This led to the discovery of highly potent compounds active against bacterial pathogens and malaria parasites in the low nanomolar range, several of which were significantly less toxic to mammalian cells. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Prudent Use of Antimicrobials in Exotic Animal Medicine.

PubMed

Broens, Els M; van Geijlswijk, Ingeborg M

2018-05-01

Reduction of antimicrobial use can result in reduction of resistance in commensal bacteria. In exotic animals, information on use of antimicrobials and resistance in commensals and pathogens is scarce. However, use of antimicrobials listed as critically important antimicrobials for human medicine seems high in exotic animals. Ideally, the selection of a therapy should be based on an accurate diagnosis and antimicrobial susceptibility testing. When prescribing antimicrobials based on empiricism, knowledge of the most common pathogens causing specific infections and the antimicrobial spectrum of antimicrobial agents is indispensable. Implementing antimicrobial stewardship promotes the prudent use of antimicrobials in exotic animals. Copyright © 2018 Elsevier Inc. All rights reserved.

Dual-species relations between Candida tropicalis isolated from apple juice ultrafiltration membranes, with Escherichia coli O157:H7 and Salmonella sp.

PubMed

Tarifa, M C; Lozano, J E; Brugnoni, L I

2015-02-01

The objective of this study was to determine the interactions between common spoilage yeast, Candida tropicalis, isolated from ultrafiltration membranes, and Escherichia coli O157:H7 and Salmonella sp. on stainless steel surfaces. Single and dual-species attachment assays were performed on stainless steel at 25°C using apple juice as culture medium. The growth of Salmonella sp. rose when it was co-cultivated with C. tropicalis in dual biofilms at 16 and 24 h; the same effect was observed for E. coli O157:H7 at 24 h. The colonization of C. tropicalis on stainless steel surfaces was reduced when it was co-cultivated with both pathogenic bacteria, reducing C. tropicalis population by at least 1.0 log unit. Visualization by SEM demonstrated that E. coli O157:H7 and Salmonella sp. adhere closely to hyphal elements using anchorage structures to attach to the surface and other cells. These results suggest a route for potential increased survival of pathogens in juice processing environments. These support the notion that the species involved interact in mixed yeast-bacteria communities favouring the development of bacteria over yeast. This study support the plausibility that pathogen interactions with strong biofilm forming members of spoilage microbiota, such as C. tropicalis, might play an important role for the survival and dissemination of E. coli O157:H7 and Salmonella sp. in food-processing environments. © 2014 The Society for Applied Microbiology.

Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Diedrich, Jonathan; Rehse, Steven J.; Palchaudhuri, Sunil

2007-07-01

A pathogenic strain of bacteria, Escherichia coli O157:H7 (enterohemorrhagic E. coli or EHEC), has been analyzed by laser-induced breakdown spectroscopy (LIBS) with nanosecond pulses and compared to three nonpathogenic E. coli strains: a laboratory strain of K-12 (AB), a derivative of the same strain termed HF4714, and an environmental strain, E. coli C (Nino C). A discriminant function analysis (DFA) was performed on the LIBS spectra obtained from live colonies of all four strains. Utilizing the emission intensity of 19 atomic and ionic transitions from trace inorganic elements, the DFA revealed significant differences between EHEC and the Nino C strain, suggesting the possibility of identifying and discriminating the pathogenic strain from commonly occurring environmental strains. EHEC strongly resembled the two K-12 strains, in particular, HF4714, making discrimination between these strains difficult. DFA was also used to analyze spectra from two of the nonpathogenic strains cultured in different media: on a trypticase soy (TS) agar plate and in a liquid TS broth. Strains cultured in different media were identified and effectively discriminated, being more similar than different strains cultured in identical media. All bacteria spectra were completely distinct from spectra obtained from the nutrient medium or ablation substrate alone. The ability to differentiate strains prepared and tested in different environments indicates that matrix effects and background contaminations do not necessarily preclude the use of LIBS to identify bacteria found in a variety of environments or grown under different conditions.

The Australian bush fly (Musca vetustissima) as a potential vector in the transmission of foodborne pathogens at outdoor eateries.

PubMed

Vriesekoop, Frank; Shaw, Rachel

2010-03-01

Abstract Australian outdoor activities are often accompanied by a barbeque (BBQ) with family, friends, and guests, which are often interrupted by uninvited guests in the form of the Australian bush fly, Musca vetustissima. We investigated the bacterial loading associated with the Australian bush in three different environments: on a cattle farm, in a typical urban area (shopping center car park), and at a BBQ. The highest bacterial populations per fly were found to occur in a farm environment ( approximately 9.1 x 10(4) CFU per fly), whereas the bacterial population was lowest on flies caught in an urban environment ( approximately 1.9 x 10(4) CFU per fly). The median CFU per fly caught near a BBQ was approximately 5.0 x 10(4). Escherichia coli was the most commonly isolated potential pathogen, whereas Shigella sp. was the least common bacterial isolate that was screened. All isolated foodborne pathogens or indicator bacteria were screened for antibiotic resistance against commonly prescribed antibiotics. This revealed a very high prevalence of multidrug resistance, especially among the Salmonella and Shigella isolates of 94% and 87% resistance, respectively, against amoxicillin, roxythromycin and cefaclor.

Rats, cities, people, and pathogens: a systematic review and narrative synthesis of literature regarding the ecology of rat-associated zoonoses in urban centers.

PubMed

Himsworth, Chelsea G; Parsons, Kirbee L; Jardine, Claire; Patrick, David M

2013-06-01

Urban Norway and black rats (Rattus norvegicus and Rattus rattus) are the source of a number of pathogens responsible for significant human morbidity and mortality in cities around the world. These pathogens include zoonotic bacteria (Leptospira interrogans, Yersina pestis, Rickettsia typhi, Bartonella spp., Streptobacillus moniliformis), viruses (Seoul hantavirus), and parasites (Angiostrongylus cantonensis). A more complete understanding of the ecology of these pathogens in people and rats is critical for determining the public health risks associated with urban rats and for developing strategies to monitor and mitigate those risks. Although the ecology of rat-associated zoonoses is complex, due to the multiple ways in which rats, people, pathogens, vectors, and the environment may interact, common determinants of human disease can still be identified. This review summarizes the ecology of zoonoses associated with urban rats with a view to identifying similarities, critical differences, and avenues for further study.

Antimicrobial properties of Cocos nucifera (coconut) husk: An extrapolation to oral health.

PubMed

Jose, Maji; Cyriac, Maria B; Pai, Vidya; Varghese, Ipe; Shantaram, Manjula

2014-07-01

Brushing the teeth with fibrous husk of Cocos nucifera (coconut) is a common oral hygiene practice among people of rural areas of South India. However, the probable antimicrobial properties of this plant material against common oral pathogens have not been proved scientifically. Therefore, the present study was designed. Alcoholic extract of the husk of Cocos nucifera was prepared and the antimicrobial properties against common oral pathogens like cariogenic bacteria, periodontal pathogens, and candidal organisms were performed by the Agar Well Diffusion Method. The results obtained were then subjected to statistical analysis using One-Way Analysis of Variance (ANOVA) and the Tukey's Honestly Significant Difference (HSD). The alcoholic extract of Cocos nucifera showed a significant concentration-dependent antimicrobial activity, expressed as a zone of inhibition with respect to all tested organisms except Actinomyces species. The inhibitory effect was more significant, with a majority of cariogenic organisms and Candida, with a zone of inhibition ranging from 4.6 mm to 16.3 mm. However, the effect was lesser with Cocos nucifera compared to chlorhexidine. Minimum inhibitory concentration (MIC) ranged from 50 mg/ml to 75 mg/ml. Cocos nucifera has a significant inhibitory action against common oral pathogens, indicating the presence of highly effective antimicrobial compounds. Therefore, it is proved that its use can contribute to oral health to a great extent. Identification of these active compounds provides the scope for incorporating it into a modern oral care system, so as to control oral diseases.

The survival of ingested Serratia marcescens in houseflies (Musca domestica L.) after electrocution with electric fly killers.

PubMed

Cooke, Edward A; O'Neill, Gael; Anderson, Moray

2003-02-01

Electric fly killers (EFKs) are commonly used to control flying insects that enter food establishments. For establishment of the incidence of pathogen-bearing insects in food establishments, insect samples obtained from EFK trays could be used. The principal difficulty with this approach is that the survival time of microorganisms on or within insect corpses after electrocution is unknown. This study determined the survival of Serratia marcescens (as a representative of the enteric bacteria) within houseflies following their electrocution by a commercial EFK. S. marcescens was successfully ingested by houseflies and survived on and within the corpses after electrocution for up to 5 weeks. Maximal levels of bacteria were recovered 24 h postelectrocution. The study also demonstrates the ability of ingested S. marcescens to out-compete resident microbial flora within houseflies. The findings are intended to pave the way for further research to determine the incidence of pathogen-laden flying insects in food establishments.

Development of a LIBS assay for the detection of Salmonella enterica serovar Typhimurium from food.

PubMed

Barnett, Cleon; Bell, Courtneé; Vig, Komal; Akpovo, A C; Johnson, Lewis; Pillai, Shreekumar; Singh, Shree

2011-07-01

Laser-induced breakdown spectroscopy (LIBS) is used for the identification of the presence of hazardous bacteria in food. In this study, our main focus was centered on the identification of S. enterica serovar Typhimurium, a Gram-negative foodborne pathogen, in various liquids such as milk, chicken broth, and brain heart infusion due to the infection being most prevalent in raw meat and dairy products. A Nd:YAG laser of operating wavelength 266 nm was used to obtain the spectra from the artificially inoculated liquid samples. A series of experiments were performed to determine the effectiveness of LIBS to discriminate the bacteria from the background liquids. These results are compared with competing modern molecular methods of detection which include polymerase chain reaction (PCR) and quantitative real-time PCR. In addition to analyzing S. enterica serovar Typhimurium, another common Gram-negative, Escherichia coli, as well as Gram-positive pathogen, Staphlycoccus auerus, were used to determine the specificity of the LIBS technique.

Escherichia coli K1 utilizes host macropinocytic pathways for invasion of brain microvascular endothelial cells.

PubMed

Loh, Lip Nam; McCarthy, Elizabeth M C; Narang, Priyanka; Khan, Naveed A; Ward, Theresa H

2017-11-01

Eukaryotic cells utilize multiple endocytic pathways for specific uptake of ligands or molecules, and these pathways are commonly hijacked by pathogens to enable host cell invasion. Escherichia coli K1, a pathogenic bacterium that causes neonatal meningitis, invades the endothelium of the blood-brain barrier, but the entry route remains unclear. Here, we demonstrate that the bacteria trigger an actin-mediated uptake route, stimulating fluid phase uptake, membrane ruffling and macropinocytosis. The route of uptake requires intact lipid rafts as shown by cholesterol depletion. Using a variety of perturbants we demonstrate that small Rho GTPases and their downstream effectors have a significant effect on bacterial invasion. Furthermore, clathrin-mediated endocytosis appears to play an indirect role in E. coli K1 uptake. The data suggest that the bacteria effect a complex interplay between the Rho GTPases to increase their chances of uptake by macropinocytosis into human brain microvascular endothelial cells. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Lactobacillus salivarius: bacteriocin and probiotic activity.

PubMed

Messaoudi, S; Manai, M; Kergourlay, G; Prévost, H; Connil, N; Chobert, J-M; Dousset, X

2013-12-01

Lactic acid bacteria (LAB) antimicrobial peptides typically exhibit antibacterial activity against food-borne pathogens, as well as spoilage bacteria. Therefore, they have attracted the greatest attention as tools for food biopreservation. In some countries LAB are already extensively used as probiotics in food processing and preservation. LAB derived bacteriocins have been utilized as oral, topical antibiotics or disinfectants. Lactobacillus salivarius is a promising probiotic candidate commonly isolated from human, porcine, and avian gastrointestinal tracts (GIT), many of which are producers of unmodified bacteriocins of sub-classes IIa, IIb and IId. It is a well-characterized bacteriocin producer and probiotic organism. Bacteriocins may facilitate the introduction of a producer into an established niche, directly inhibit the invasion of competing strains or pathogens, or modulate the composition of the microbiota and influence the host immune system. This review gives an up-to-date overview of all L. salivarius strains, isolated from different origins, known as bacteriocin producing and/or potential probiotic. Copyright © 2013 Elsevier Ltd. All rights reserved.

Opportunistic respiratory pathogens in the oral cavity of the elderly.

PubMed

Tada, Akio; Hanada, Nobuhiro

2010-10-01

The oral cavity of the hospitalized or bedridden elderly is often a reservoir for opportunistic pathogens associated with respiratory diseases. Commensal flora and the host interact in a balanced fashion and oral infections are considered to appear following an imbalance in the oral resident microbiota, leading to the emergence of potentially pathogenic bacteria. The definition of the process involved in colonization by opportunistic respiratory pathogens needs to elucidate the factors responsible for the transition of the microbiota from commensal to pathogenic flora. The regulatory factors influencing the oral ecosystem can be divided into three major categories: the host defense system, commensal bacteria, and external pathogens. In this article, we review the profile of these categories including the intricate cellular interaction between immune factors and commensal bacteria and the disturbance in homeostasis in the oral cavity of hospitalized or bedridden elderly, which facilitates oral colonization by opportunistic respiratory pathogens. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Smoking and periodontal disease: discrimination of antibody responses to pathogenic and commensal oral bacteria.

PubMed

Hayman, L; Steffen, M J; Stevens, J; Badger, E; Tempro, P; Fuller, B; McGuire, A; Al-Sabbagh, Mohanad; Thomas, M V; Ebersole, J L

2011-04-01

Smoking is an independent risk factor for the initiation, extent and severity of periodontal disease. This study examined the ability of the host immune system to discriminate commensal oral bacteria from pathogens at mucosal surfaces, i.e. oral cavity. Serum immunoglobulin (Ig)G antibody reactive with three pathogenic and five commensal oral bacteria in 301 current smokers (age range 21-66 years) were examined by enzyme-linked immunosorbent assay. Clinical features of periodontal health were used as measures of periodontitis. Antibody to the pathogens and salivary cotinine levels were related positively to disease severity; however, the antibody levels were best described by the clinical disease unrelated to the amount of smoking. The data showed a greater immune response to pathogens than commensals that was related specifically to disease extent, and most noted in black males. Significant correlations in individual patient responses to the pathogens and commensals were lost with an increasing extent of periodontitis and serum antibody to the pathogens. Antibody to Porphyromonas gingivalis was particularly distinct with respect to the discriminatory nature of the immune responses in recognizing the pathogens. Antibody responses to selected pathogenic and commensal oral microorganisms differed among racial groups and genders. The antibody response to the pathogens was related to disease severity. The level of antibody to the pathogens, and in particular P. gingivalis, was correlated with disease severity in black and male subsets of patients. The amount of smoking did not appear to impact directly serum antibody levels to these oral bacteria. © 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.

Computers in anesthesia and intensive care: lack of evidence that the central unit serves as reservoir of pathogens.

PubMed

Quinzio, Lorenzo; Blazek, Michael; Hartmann, Bernd; Röhrig, Rainer; Wille, Burkhard; Junger, Axel; Hempelmann, Gunter

2005-01-01

Computers are becoming increasingly visible in operating rooms (OR) and intensive care units (ICU) for use in bedside documentation. Recently, they have been suspected as possibly acting as reservoirs for microorganisms and vehicles for the transfer of pathogens to patients, causing nosocomial infections. The purpose of this study was to examine the microbiological (bacteriological and mycological) contamination of the central unit of computers used in an OR, a surgical and a pediatric ICU of a tertiary teaching hospital. Sterile swab samples were taken from five sites in each of 13 computers stationed at the two ICUs and 12 computers at the OR. Sample sites within the chassis housing of the computer processing unit (CPU) included the CPU fan, ventilator, and metal casing. External sites were the ventilator and the bottom of the computer tower. Quantitative and qualitative microbiological analyses were performed according to commonly used methods. One hundred and ninety sites were cultured for bacteria and fungi. Analyses of swabs taken at five equivalent sites inside and outside the computer chassis did not find any significant-number of potentially pathogenic bacteria or fungi. This can probably be attributed to either the absence or the low number of pathogens detected on the surfaces. Microbial contamination in the CPU of OR and ICU computers is too low for designating them as a reservoir for microorganisms.

[Etiological surveillance and analysis of infectious diarrhea in Beijing in year 2010].

PubMed

Huang, Fang; Deng, Ying; Qu, Mei; Liu, Gui-Rong; Liu, Yuan; Zhang, Xin; Li, Jie; Yan, Han-Qiu; Gao, Zhi-Yong; Liu, Bai-Wei; Li, Xi-Tai; Li, Xin-Yu

2011-09-01

To explore the pathogenic form, epidemic features and serotype distribution of the pathogenic bacteria causing infectious diarrhea in Beijing. A total of 2118 samples of rectal swabs and stool specimens of diarrheal patients were collected from 6 surveillant intestinal tract clinics during the period between April and October, 2010. Enteric multiple pathogens including Vibrio cholerae, Vibrio parahaemolyticus, Salmonella, Shigella and diarrheagenic Escherichia coli were detected by the isolation culture, biochemical identification and serotyping methods. The population distribution, temporal distribution and serotype distribution of the above pathogenic bacteria were analyzed by descriptive statistical methods. 478 strains isolated from the total 2118 specimens were positive for pathogen detection, accounting to 22.6%. Among the 478 strains of pathogenic bacteria, Shigella accounting for 40.8% (195/478) was the most frequent pathogen, followed by Vibrio parahaemolyticus accouting for 23.8% (114/478), Salmonella accounting for 19.0% (91/478) and diarrheagenic Escherichia coli accounting for 4.8% (23/478). Enteric pathogenic bacteria spread mainly among adults aging between 20 and 39; and the distribution was different among different age groups, while the highest detected rate was in 30 - 39 age group, accounting for 27.2% (92/338). The detected rate of pathogenic bacteria showed evident seasonal variations, with a peak from July to October, whose detected rates were 23.5% (114/486), 32.8% (176/536), 36.1% (90/249) and 25.9% (29/112) respectively. The detected rates in other months were all under 16.0%. Shigella Sonnei was the dominant serotype, accounting for 83.1% (162/195). O3:K6 was the dominant serotype among Vibrio parahaemolyticus, accounting for 63.2% (72/114). Salmonella Enteritidis and Salmonella Typhimurium were dominant serotypes among Salmonella, accounting for 13.2% (12/91) and 12.1% (11/91) separately. Enterpathogenic Escherichia coli and enterotoxigenic Escherichia coli were the dominant serotypes among Diarrheagenic Escherichia coli, accounting for 69.6% (16/23) and 30.4% (7/23) respectively. The three main pathogenic bacteria causing infectious diarrhea in Beijing are Shigella, Vibrio parahaemolyticus, Salmonella; and there are obvious changes in the serotype distribution of Shigella and Samonella compared to previous years.

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

Detection of multiple potentially pathogenic bacteria in Matang mangrove estuaries, Malaysia.

PubMed

Ghaderpour, Aziz; Mohd Nasori, Khairul Nazrin; Chew, Li Lee; Chong, Ving Ching; Thong, Kwai Lin; Chai, Lay Ching

2014-06-15

The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multidrug-resistant organisms in neonatal sepsis in two tertiary neonatal ICUs, Egypt.

PubMed

Awad, Hesham A; Mohamed, Maha H; Badran, Nabil F; Mohsen, Manal; Abd-Elrhman, Al-Sayed A

2016-03-01

Neonatal sepsis remains a serious problem in any neonatal intensive care unit (NICU). Bacterial organisms have developed increased resistance to commonly used antibiotics. Because not enough data are available from Egypt, the aim of the present study was to determine the causative bacteria and the level of their resistance to commonly used antibiotics in tertiary NICUs in Cairo, Egypt. A 3.5-year retrospective study was carried out at NICUs of the Children's Hospital of Ain Shams University and that of El-Hussein Hospital, Al-Azhar University, Egypt. Records of neonates were reviewed. All neonates with culture-proven sepsis were included in the study. Almost one-third of the admitted neonates (33.4%) were diagnosed as having neonatal sepsis, 32.25% of them culture-proven. Early/late onset sepsis was found in 35.4 and 64.6%, respectively. Gram-negative/gram-positive bacteria was found in 68 to 25.6%. Fungal infection was detected in 9% of the isolates. Escherichia coli was the main pathogen isolated in both early-onset sepsis (41.2%) and late-onset sepsis (24.5%). Overall, 77% of the isolates were multidrug-resistant (60% of gram-positive bacteria and 83.4% of gram-negative bacteria). Nearly 80% (79%) of mortality was caused by multidrug-resistant organisms. Gram-positive and gram-negative bacteria showed high resistance against commonly used antibiotics such as ampicillin, amoxicillin, cefotaxime, ceftriaxone, and gentamicin. There is an alarming increase in antibiotic resistance to the commonly used antibiotics. Continuous surveillance for antibiotic susceptibility is needed to ensure proper empirical therapy. Improvement of infection control practices, avoidance of irrational use of antibiotics, and revision of the protocols are mandatory in the prevention of neonatal sepsis.

Pathogen bacteria adhesion to skin mucus of fishes.

PubMed

Benhamed, Said; Guardiola, Francisco A; Mars, Mohammed; Esteban, María Ángeles

2014-06-25

Fish are always in intimate contact with their environment; therefore they are permanently exposed to very vary external hazards (e.g. aerobic and anaerobic bacteria, viruses, parasites, pollutants). To fight off pathogenic microorganisms, the epidermis and its secretion, the mucus acts as a barrier between the fish and the environment. Fish are surrounded by a continuous layer of mucus which is the first physical, chemical and biological barrier from infection and the first site of interaction between fish's skin cells and pathogens. The mucus composition is very complex and includes numerous antibacterial factors secreted by fish's skin cells, such as immunoglobulins, agglutinins, lectins, lysins and lysozymes. These factors have a very important role to discriminate between pathogenic and commensal microorganisms and to protect fish from invading pathogens. Furthermore, the skin mucus represents an important portal of entry of pathogens since it induces the development of biofilms, and represents a favorable microenvironment for bacteria, the main disease agents for fish. The purpose of this review is to summarize the current knowledge of the interaction between bacteria and fish skin mucus, the adhesion mechanisms of pathogens and the major factors influencing pathogen adhesion to mucus. The better knowledge of the interaction between fish and their environment could inspire other new perspectives to study as well as to exploit the mucus properties for different purposes. Copyright © 2014 Elsevier B.V. All rights reserved.

Amixicile, a novel strategy for targeting oral anaerobic pathogens.

PubMed

Hutcherson, Justin A; Sinclair, Kathryn M; Belvin, Benjamin R; Gui, Qin; Hoffman, Paul S; Lewis, Janina P

2017-09-05

The oral microflora is composed of both health-promoting as well as disease-initiating bacteria. Many of the disease-initiating bacteria are anaerobic and include organisms such as Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. Here we investigated a novel therapeutic, amixicile, that targets pyruvate:ferredoxin oxidoreductase (PFOR), a major metabolic enzyme involved in energy generation through oxidative decarboxylation of pyruvate. PFOR is present in these anaerobic pathogenic bacteria and thus we hypothesized that amixicile would effectively inhibit their growth. In general, PFOR is present in all obligate anaerobic bacteria, while oral commensal aerobes, including aerotolerant ones, such as Streptococcus gordonii, use pyruvate dehydrogenase to decarboxylate pyruvate. Accordingly, we observed that growth of the PFOR-containing anaerobic periodontal pathogens, grown in both monospecies as well as multispecies broth cultures was inhibited in a dose-dependent manner while that of S. gordonii was unaffected. Furthermore, we also show that amixicile is effective against these pathogens grown as monospecies and multispecies biofilms. Finally, amixicile is the first selective therapeutic agent active against bacteria internalized by host cells. Together, the results show that amixicile is an effective inhibitor of oral anaerobic bacteria and as such, is a good candidate for treatment of periodontal diseases.

Antimicrobial Activities of Bacteria Associated with the Brown Alga Padina pavonica

PubMed Central

Ismail, Amel; Ktari, Leila; Ahmed, Mehboob; Bolhuis, Henk; Boudabbous, Abdellatif; Stal, Lucas J.; Cretoiu, Mariana Silvia; El Bour, Monia

2016-01-01

Macroalgae belonging to the genus Padina are known to produce antibacterial compounds that may inhibit growth of human- and animal pathogens. Hitherto, it was unclear whether this antibacterial activity is produced by the macroalga itself or by secondary metabolite producing epiphytic bacteria. Here we report antibacterial activities of epiphytic bacteria isolated from Padina pavonica (Peacocks tail) located on northern coast of Tunisia. Eighteen isolates were obtained in pure culture and tested for antimicrobial activities. Based on the 16S rRNA gene sequences the isolates were closely related to Proteobacteria (12 isolates; 2 Alpha- and 10 Gammaproteobacteria), Firmicutes (4 isolates) and Actinobacteria (2 isolates). The antimicrobial activity was assessed as inhibition of growth of 12 species of pathogenic bacteria (Aeromonas salmonicida, A. hydrophila, Enterobacter xiangfangensis, Enterococcus faecium, Escherichia coli, Micrococcus sp., Salmonella typhimurium, Staphylococcus aureus, Streptococcus sp., Vibrio alginoliticus, V. proteolyticus, V. vulnificus) and one pathogenic yeast (Candida albicans). Among the Firmicutes, isolate P8, which is closely related to Bacillus pumilus, displayed the largest spectrum of growth inhibition of the pathogenic bacteria tested. The results emphasize the potential use of P. pavonica associated antagonistic bacteria as producers of novel antibacterial compounds. PMID:27462308

Chemical signaling between plants and plant-pathogenic bacteria.

PubMed

Venturi, Vittorio; Fuqua, Clay

2013-01-01

Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.

Mining virulence genes using metagenomics.

PubMed

Belda-Ferre, Pedro; Cabrera-Rubio, Raúl; Moya, Andrés; Mira, Alex

2011-01-01

When a bacterial genome is compared to the metagenome of an environment it inhabits, most genes recruit at high sequence identity. In free-living bacteria (for instance marine bacteria compared against the ocean metagenome) certain genomic regions are totally absent in recruitment plots, representing therefore genes unique to individual bacterial isolates. We show that these Metagenomic Islands (MIs) are also visible in bacteria living in human hosts when their genomes are compared to sequences from the human microbiome, despite the compartmentalized structure of human-related environments such as the gut. From an applied point of view, MIs of human pathogens (e.g. those identified in enterohaemorragic Escherichia coli against the gut metagenome or in pathogenic Neisseria meningitidis against the oral metagenome) include virulence genes that appear to be absent in related strains or species present in the microbiome of healthy individuals. We propose that this strategy (i.e. recruitment analysis of pathogenic bacteria against the metagenome of healthy subjects) can be used to detect pathogenicity regions in species where the genes involved in virulence are poorly characterized. Using this approach, we detect well-known pathogenicity islands and identify new potential virulence genes in several human pathogens.

The isolation of salmonellae, Newcastle disease virus and other infectious agents from quarantined imported birds in Canada.

PubMed Central

Rigby, C E; Pettit, J R; Papp-Vid, G; Spencer, J L; Willis, N G

1981-01-01

Necropsy and culture results are presented for 269 consignments of imported birds (mainly psittacine and passerine species) examined between January 1977 and August 1980. Consignments were submitted for diagnosis of clinical illness or deaths occurring among these birds while they were in quarantine before entry into Canada. Enteritis and injury were the most frequent diagnoses. Pathogens or potential pathogens were isolated from 77% of consignments. Newcastle disease virus was isolated nine times, and Chlamydia psittaci was isolated once. Escherichia coli (from 113 consignments) and salmonellae (from 49) were the most common bacteria isolated, and reoviruses (from 22) and paramyxoviruses other than Newcastle disease virus (from 22) were the most common viruses. Salmonella typhimurium was the most common Salmonella serovar. Salmonella hadar was isolated from turkey poults imported from Great Britain. The possible public health significance of the role of imported birds in the introduction of exotic Salmonella serovars, or of serovars resistant to several antimicrobials is discussed. PMID:7039785

The Differential Effects of Anesthetics on Bacterial Behaviors

PubMed Central

Chamberlain, Matthew; Koutsogiannaki, Sophia; Schaefers, Matthew; Babazada, Hasan; Liu, Renyu; Yuki, Koichi

2017-01-01

Volatile anesthetics have been in clinical use for a long period of time and are considered to be promiscuous by presumably interacting with several ion channels in the central nervous system to produce anesthesia. Because ion channels and their existing evolutionary analogues, ion transporters, are very important in various organisms, it is possible that volatile anesthetics may affect some bacteria. In this study, we hypothesized that volatile anesthetics could affect bacterial behaviors. We evaluated the impact of anesthetics on bacterial growth, motility (swimming and gliding) and biofilm formation of four common bacterial pathogens in vitro. We found that commonly used volatile anesthetics isoflurane and sevoflurane affected bacterial motility and biofilm formation without any effect on growth of the common bacterial pathogens studied here. Using available Escherichia coli gene deletion mutants of ion transporters and in silico molecular docking, we suggested that these altered behaviors might be at least partly via the interaction of volatile anesthetics with ion transporters. PMID:28099463

Ticks and Tick-Borne Pathogens of the Caribbean: Current Understanding and Future Directions for More Comprehensive Surveillance.

PubMed

Gondard, Mathilde; Cabezas-Cruz, Alejandro; Charles, Roxanne A; Vayssier-Taussat, Muriel; Albina, Emmanuel; Moutailler, Sara

2017-01-01

Ticks are obligate hematophagous arthropods of significant importance to human and veterinary medicine. They transmit a vast array of pathogens, including bacteria, viruses, protozoa, and helminths. Most epidemiological data on ticks and tick-borne pathogens (TBPs) in the West Indies are limited to common livestock pathogens such as Ehrlichia ruminantium, Babesia spp. (i.e., B. bovis and B. bigemina ), and Anaplasma marginale , and less information is available on companion animal pathogens. Of note, human tick-borne diseases (TBDs) remain almost completely uncharacterized in the West Indies. Information on TBP presence in wildlife is also missing. Herein, we provide a comprehensive review of the ticks and TBPs affecting human and animal health in the Caribbean, and introduce the challenges associated with understanding TBD epidemiology and implementing successful TBD management in this region. In particular, we stress the need for innovative and versatile surveillance tools using high-throughput pathogen detection (e.g., high-throughput real-time microfluidic PCR). The use of such tools in large epidemiological surveys will likely improve TBD prevention and control programs in the Caribbean.

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

PubMed

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

2006-01-01

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

Genetic islands in pome fruit pathogenic and non-pathogenic Erwinia species and related plasmids

PubMed Central

Llop, Pablo

2015-01-01

New pathogenic bacteria belonging to the genus Erwinia associated with pome fruit trees (Erwinia, E. piriflorinigrans, E. uzenensis) have been increasingly described in the last years, and comparative analyses have found that all these species share several genetic characteristics. Studies at different level (whole genome comparison, virulence genes, plasmid content, etc.) show a high intraspecies homogeneity (i.e., among E. amylovora strains) and also abundant similarities appear between the different Erwinia species: presence of plasmids of similar size in the pathogenic species; high similarity in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes, in the chromosomes. Many genetic similarities have been observed also among some of the plasmids (and genomes) from the pathogenic species and E. tasmaniensis or E. billingiae, two epiphytic species on the same hosts. The amount of genetic material shared in this genus varies from individual genes to clusters, genomic islands and genetic material that even may constitute a whole plasmid. Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and several pathogenic traits that are still present. How this common material has been obtained and is efficiently maintained in different species belonging to the same genus sharing a common ecological niche provides an idea of the origin and evolution of the pathogenic Erwinia and the interaction with non-pathogenic species present in the same niche, and the role of the genes that are conserved in all of them. PMID:26379649

Synthesis of UDP-apiose in Bacteria: The marine phototroph Geminicoccus roseus and the plant pathogen Xanthomonas pisi.

PubMed

Smith, James Amor; Bar-Peled, Maor

2017-01-01

The branched-chain sugar apiose was widely assumed to be synthesized only by plant species. In plants, apiose-containing polysaccharides are found in vascularized plant cell walls as the pectic polymers rhamnogalacturonan II and apiogalacturonan. Apiosylated secondary metabolites are also common in many plant species including ancestral avascular bryophytes and green algae. Apiosyl-residues have not been documented in bacteria. In a screen for new bacterial glycan structures, we detected small amounts of apiose in methanolic extracts of the aerobic phototroph Geminicoccus roseus and the pathogenic soil-dwelling bacteria Xanthomonas pisi. Apiose was also present in the cell pellet of X. pisi. Examination of these bacterial genomes uncovered genes with relatively low protein homology to plant UDP-apiose/UDP-xylose synthase (UAS). Phylogenetic analysis revealed that these bacterial UAS-like homologs belong in a clade distinct to UAS and separated from other nucleotide sugar biosynthetic enzymes. Recombinant expression of three bacterial UAS-like proteins demonstrates that they actively convert UDP-glucuronic acid to UDP-apiose and UDP-xylose. Both UDP-apiose and UDP-xylose were detectable in cell cultures of G. roseus and X. pisi. We could not, however, definitively identify the apiosides made by these bacteria, but the detection of apiosides coupled with the in vivo transcription of bUAS and production of UDP-apiose clearly demonstrate that these microbes have evolved the ability to incorporate apiose into glycans during their lifecycles. While this is the first report to describe enzymes for the formation of activated apiose in bacteria, the advantage of synthesizing apiose-containing glycans in bacteria remains unknown. The characteristics of bUAS and its products are discussed.

Burn-associated bloodstream infections in pediatric burn patients: Time distribution of etiologic agents.

PubMed

Devrim, İlker; Kara, Ahu; Düzgöl, Mine; Karkıner, Aytaç; Bayram, Nuri; Temir, Günyüz; Şencan, Arzu; Sorguç, Yelda; Gülfidan, Gamze; Hoşgör, Münevver

2017-02-01

Infections are the leading cause of morbidity and mortality in patients with burns in burn units. Bloodstream infections (BSIs) in patients with burns may result from burn wound infection, use of invasive devices such as central venous catheters, and translocation of the gastrointestinal flora. In this study, we investigated the distribution and antimicrobial drug resistance of causative pathogens in children with burns and the durational changes of microorganisms in the distribution of BSIs in children. This study was conducted at the Pediatric Burn Unit (PBU) of Dr. Behçet Uz Children Research and Training Hospital during the period of November 2008-April 2015. The study subjects were all the patients admitted to the PBU, in whom microorganisms were isolated at least from one of the cultures, including blood and catheter cultures. Gram-positive bacteria were the most common causative agents of BSI in patients with burns (66.4%), followed by gram-negative bacteria (22.1%) and fungi (11.5%). The median duration of development of BSIs caused by gram-positive bacteria from the time of burn was 5 days (ranging from 2 to 54 days of burn), which was significantly shorter than that of BSIs caused by gram-negative bacteria (12 days) and fungal pathogens (13 days). The etiologic agents of BSIs in children may differ from those in adults. Gram-negative drug-resistant bacteria such as multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii were important agents of BSI in patients with burns, especially in the long term; however, gram-positive bacteria should also be considered while deciding the antimicrobial therapy, especially in the early periods of burn. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

[Uncommon non-fermenting Gram-negative rods as pathogens of lower respiratory tract infection].

PubMed

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

2018-01-01

Glucose non-fermenting Gram-negative bacteria are ubiquitous environmental organisms. Most of them are identified as opportunistic, nosocomial pathogens in patients. Uncommon species are identified accurately, mainly due to the introduction of matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS) in clinical microbiology practice. Most of these uncommon non-fermenting rods are isolated from lower respiratory tract samples. Their significance in lower respiratory tract infections, such as rules of their testing are not clarified yet. The aim of this study was to review the clinical microbiological features of these bacteria, especially their roles in lower respiratory tract infections and antibiotic treatment options. Lower respiratory tract samples of 3589 patients collected in a four-year period (2013-2016) were analyzed retrospectively at Semmelweis University (Budapest, Hungary). Identification of bacteria was performed by MALDI-TOF MS, the antibiotic susceptibility was tested by disk diffusion method. Stenotrophomonas maltophilia was revealed to be the second, whereas Acinetobacter baumannii the third most common non-fermenting rod in lower respiratory tract samples, behind the most common Pseudomonas aeruginosa. The total number of uncommon non-fermenting Gram-negative isolates was 742. Twenty-three percent of isolates were Achromobacter xylosoxidans. Beside Chryseobacterium, Rhizobium, Delftia, Elizabethkingia, Ralstonia and Ochrobactrum species, and few other uncommon species were identified among our isolates. The accurate identification of this species is obligatory, while most of them show intrinsic resistance to aminoglycosides. Resistance to ceftazidime, cefepime, piperacillin-tazobactam and carbapenems was frequently observed also. Ciprofloxacin, levofloxacin and trimethoprim-sulfamethoxazole were found to be the most effective antibiotic agents. Orv Hetil. 2018; 159(1): 23-30.

Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria.

PubMed

Antunes, Camila Azevedo; Clark, Laura; Wanuske, Marie-Therès; Hacker, Elena; Ott, Lisa; Simpson-Louredo, Liliane; de Luna, Maria das Gracas; Hirata, Raphael; Mattos-Guaraldi, Ana Luíza; Hodgkin, Jonathan; Burkovski, Andreas

2016-01-01

Caenorhabditis elegans is one of the major model systems in biology based on advantageous properties such as short life span, transparency, genetic tractability and ease of culture using an Escherichia coli diet. In its natural habitat, compost and rotting plant material, this nematode lives on bacteria. However, C. elegans is a predator of bacteria, but can also be infected by nematopathogenic coryneform bacteria such Microbacterium and Leucobacter species, which display intriguing and diverse modes of pathogenicity. Depending on the nematode pathogen, aggregates of worms, termed worm-stars, can be formed, or severe rectal swelling, so-called Dar formation, can be induced. Using the human and animal pathogens Corynebacterium diphtheriae and Corynebacterium ulcerans as well as the non-pathogenic species Corynebacterium glutamicum, we show that these coryneform bacteria can also induce star formation slowly in worms, as well as a severe tail-swelling phenotype. While C. glutamicum had a significant, but minor influence on survival of C. elegans, nematodes were killed after infection with C. diphtheriae and C. ulcerans. The two pathogenic species were avoided by the nematodes and induced aversive learning in C. elegans.

A prebiotic role of Ecklonia cava improves the mortality of Edwardsiella tarda-infected zebrafish models via regulating the growth of lactic acid bacteria and pathogen bacteria.

PubMed

Lee, WonWoo; Oh, Jae Young; Kim, Eun-A; Kang, Nalae; Kim, Kil-Nam; Ahn, Ginnae; Jeon, You-Jin

2016-07-01

In this study, the beneficial prebiotic roles of Ecklonia cava (E. cava, EC) were evaluated on the growth of lactic acid bacteria (LAB) and pathogen bacteria and the mortality of pathogen-bacteria infected zebrafish model. The result showed that the original E. cava (EC) led to the highest growth effects on three LABs (Lactobacillus brevis, L. brevis; Lactobacillus pentosus, L. pentosus; Lactobacillus plantarum; L. plantarum) and it was dose-dependent manners. Also, EC, its Celluclast enzymatic (ECC) and 100% ethanol extracts (ECE) showed the anti-bacterial activities on the fish pathogenic bacteria such as (Edwardsiella tarda; E. tarda, Streptococcus iniae; S. iniae, and Vibrio harveyi; V. harveyi). Interestingly, EC induced the higher production of the secondary metabolites from L. plantarum in MRS medium. The secondary metabolites produced by EC significantly inhibited the growth of pathogen bacteria. In further in vivo study, the co-treatment of EC and L. plantarum improved the growth and mortality of E. tarda-infected zebrafish as regulating the expression of inflammatory molecules such as iNOS and COX2. Taken together, our present study suggests that the EC plays an important role as a potential prebiotic and has a protective effect against the infection caused by E. tarda injection in zebrafish. Also, our conclusion from this evidence is that EC can be used and applied as a useful prebiotic. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification and Pathogenicity of Bacteria Associated with Etiolation and Decline of Creeping Bentgrass Golf Course Putting Greens.

PubMed

Roberts, Joseph A; Ma, Bangya; Tredway, Lane P; Ritchie, David F; Kerns, James P

2018-01-01

Bacterial etiolation and decline has developed into a widespread issue with creeping bentgrass (CBG) (Agrostis stolonifera) putting green turf. The condition is characterized by an abnormal elongation of turfgrass stems and leaves that in rare cases progresses into a rapid and widespread necrosis and decline. Recent reports have cited bacteria, Acidovorax avenae and Xanthomonas translucens, as causal agents; however, few cases exist where either bacterium were isolated in conjunction with turf exhibiting bacterial disease symptoms. From 2010 to 2014, turfgrass from 62 locations submitted to the NC State Turf Diagnostic Clinic exhibiting bacterial etiolation and/or decline symptoms were sampled for the presence of bacterial pathogens. Isolated bacteria were identified using rRNA sequencing of the 16S subunit and internal transcribed spacer region (16S-23S or ITS). Results showed diverse bacteria isolated from symptomatic turf and A. avenae and X. translucens were only isolated in 26% of samples. Frequently isolated bacterial species were examined for pathogenicity to 4-week-old 'G2' CBG seedlings and 8-week-old 'A-1' CBG turfgrass stands in the greenhouse. While results confirmed pathogenicity of A. avenae and X. translucens, Pantoea ananatis was also shown to infect CBG turf; although pathogenicity varied among isolated strains. These results illustrate that multiple bacteria are associated with bacterial disease and shed new light on culturable bacteria living in CBG turfgrass putting greens. Future research to evaluate additional microorganisms (i.e., bacteria and fungi) could provide new information on host-microbe interactions and possibly develop ideas for management tactics to reduce turfgrass pests.

Cladophora (Chlorophyta) spp. Harbor Human Bacterial Pathogens in Nearshore Water of Lake Michigan†

PubMed Central

Ishii, Satoshi; Yan, Tao; Shively, Dawn A.; Byappanahalli, Muruleedhara N.; Whitman, Richard L.; Sadowsky, Michael J.

2006-01-01

Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attached Cladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. While Shigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 × 103 cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 × 102 Campylobacter cells/g Cladophora in 60 to 100% of lake- and ditchside samples. The Campylobacter densities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for Campylobacter and Salmonella species, our results suggest that Cladophora is a likely secondary habitat for pathogenic bacteria in Lake Michigan and that the association of these bacteria with Cladophora warrants additional studies to assess the potential health impact on beach users. PMID:16820442

Cladophora (Chlorophyta) spp. harbor human bacterial pathogens in nearshore water of Lake Michigan.

PubMed

Ishii, Satoshi; Yan, Tao; Shively, Dawn A; Byappanahalli, Muruleedhara N; Whitman, Richard L; Sadowsky, Michael J

2006-07-01

Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attached Cladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. While Shigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 x 10(3) cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 x 10(2) Campylobacter cells/g Cladophora in 60 to 100% of lake- and ditchside samples. The Campylobacter densities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for Campylobacter and Salmonella species, our results suggest that Cladophora is a likely secondary habitat for pathogenic bacteria in Lake Michigan and that the association of these bacteria with Cladophora warrants additional studies to assess the potential health impact on beach users.

Rapid Bacterial Detection via an All-Electronic CMOS Biosensor

PubMed Central

Nikkhoo, Nasim; Cumby, Nichole; Gulak, P. Glenn; Maxwell, Karen L.

2016-01-01

The timely and accurate diagnosis of infectious diseases is one of the greatest challenges currently facing modern medicine. The development of innovative techniques for the rapid and accurate identification of bacterial pathogens in point-of-care facilities using low-cost, portable instruments is essential. We have developed a novel all-electronic biosensor that is able to identify bacteria in less than ten minutes. This technology exploits bacteriocins, protein toxins naturally produced by bacteria, as the selective biological detection element. The bacteriocins are integrated with an array of potassium-selective sensors in Complementary Metal Oxide Semiconductor technology to provide an inexpensive bacterial biosensor. An electronic platform connects the CMOS sensor to a computer for processing and real-time visualization. We have used this technology to successfully identify both Gram-positive and Gram-negative bacteria commonly found in human infections. PMID:27618185

Bioprospecting saline gradient of a Wildlife Sanctuary for bacterial diversity and antimicrobial activities.

PubMed

DeLuca, Mara; King, Riley; Morsy, Mustafa

2017-08-11

Antibiotic-resistant bacteria are becoming a global crisis, causing death of thousands of people and significant economic impact. The discovery of novel antibiotics is crucial to saving lives and reducing healthcare costs. To address the antibiotic-resistant crisis, in collaboration the Small World Initiative, which aims to crowdsource novel antibiotic discovery, this study aimed to identify antimicrobial producing bacteria and bacterial diversity in the soil of the Stimpson Wildlife Sanctuary, an inland area with a soil salt gradient. Approximately 4500 bacterial colonies were screened for antimicrobial activity and roughly 100 bacteria were identified as antimicrobial producers, which belong to Entrococcaceae (74%), Yersiniaceae (19%), and unidentified families (7%). Several bacterial isolates showed production of broad spectrum inhibitory compounds, while others were more specific to certain pathogens. The data obtained from the current study provide a resource for further characterization of the soil bacteria with antimicrobial activity, with an aim to discover novel ones. The study showed no correlation between soil salt level and the presence of bacteria with antimicrobial activities. However, most of the identified antimicrobial producing bacteria do not belong to actinomycetes, the most common phyla of antibiotic producing bacteria and this could potentially lead to the discovery of novel antibiotics.

New Innovations in Biological Control of Mosquitoes.

USDA-ARS?s Scientific Manuscript database

Biological control of mosquitoes is a component of an integrated pest management strategy and includes general predators, parasites and pathogens. Pathogens of mosquitoes include bacteria, viruses, fungi and protists. The most successful group for applied mosquito control include the bacteria Baci...

QUANTITATIVE ASSESSMENT OF PATHOGENS IN DRINKING WATER

EPA Science Inventory

The project has been summarized in a series of peer-reviewed published papers as outlined in the Publication section of this report. Pathogens capable of causing waterborne diseases include bacteria, protozoa, and viruses. Fecal indicator bacteria are the primary microorganisms u...

Plant pathogenic anaerobic bacteria use aromatic polyketides to access aerobic territory.

PubMed

Shabuer, Gulimila; Ishida, Keishi; Pidot, Sacha J; Roth, Martin; Dahse, Hans-Martin; Hertweck, Christian

2015-11-06

Around 25% of vegetable food is lost worldwide because of infectious plant diseases, including microbe-induced decay of harvested crops. In wet seasons and under humid storage conditions, potato tubers are readily infected and decomposed by anaerobic bacteria (Clostridium puniceum). We found that these anaerobic plant pathogens harbor a gene locus (type II polyketide synthase) to produce unusual polyketide metabolites (clostrubins) with dual functions. The clostrubins, which act as antibiotics against other microbial plant pathogens, enable the anaerobic bacteria to survive an oxygen-rich plant environment. Copyright © 2015, American Association for the Advancement of Science.

Occurrence and distribution of fecal indicator bacteria and gene markers of pathogenic bacteria in Great Lakes tributaries, March-October 2011

USGS Publications Warehouse

Brennan, Angela K.; Johnson, Heather E.; Totten, Alexander R.; Duris, Joseph W.

2015-01-01

Water samples were analyzed for the presence of FIB concentrations (FIB; fecal coliform bacteria, Escherichia coli [E. coli], and enterococci) by using membrane filtration and serial dilution methods. The resulting enrichments from standard culturing of the samples were then analyzed by using polymerase chain reaction (PCR) to determine the occurrence of pathogen gene markers for Shigella species, Campylobacter jejuni and coli, Salmonellaspecies, and pathogenic E. coli, including Shiga toxin-producing E. coli (STEC).

The use of oral antibiotics in treating acne vulgaris: a new approach.

PubMed

Farrah, Georgia; Tan, Ernest

2016-09-01

Although acne is not an infectious disease, oral antibiotics have remained a mainstay of treatment over the last 40 years. The anti-inflammatory properties of oral antibiotics, particularly the tetracyclines, are efficacious in treating inflammatory acne lesions. Common prescribing practices in Dermatology exert significant selection pressure on bacteria, contributing to the development of antibiotic resistance. Antibiotic use for acne not only promotes resistance in Propionibacterium acnes, but also affects other host bacteria with pathogenic potential. This review will summarize the commonly used treatments for acne vulgaris, and how they should be combined as rational treatment. The indications for using oral antibiotics in acne will be highlighted. Strategies described in the literature to conserve the utility of oral antibiotics will be summarized. These include limiting the duration of antibiotic therapy, concomitant use of a topical non-antibiotic agent, use of subantimicrobial dose doxycycline, and the introduction of topical dapsone. © 2016 Wiley Periodicals, Inc.

[Erwinia amylovora--the fire blight pathogen of trees in Ukraine].

PubMed

Iakovleva, L M; Moroz, S N; Shcherbina, T N; Ogorodnik, L E; Gvozdiak, R I; Patyka, V F

2014-01-01

Niduses of fire blight of fruit and ornamental trees have been found in the Kyiv and Vinnitsa regions of Ukraine. Pathogen Erwinia amylovora was isolated between April and October. The pathogen was often accompanied by bacteria Pseudomonas syringae pv. syringae. Artificial infection with a mixture of bacteria E. amylovora and P. syringae pv. syringae accelerates and enhances the disease process in the laboratory.

Diagnosis of Sepsis with Cell-free DNA by Next-Generation Sequencing Technology in ICU Patients.

PubMed

Long, Yun; Zhang, Yinxin; Gong, Yanping; Sun, Ruixue; Su, Longxiang; Lin, Xin; Shen, Ao; Zhou, Jiali; Caiji, Zhuoma; Wang, Xinying; Li, Dongfang; Wu, Honglong; Tan, Hongdong

2016-07-01

Bacteremia is a common serious manifestation of disease in the intensive care unit (ICU), which requires quick and accurate determinations of pathogens to select the appropriate antibiotic treatment. To overcome the shortcomings of traditional bacterial culture (BC), we have adapted next-generation sequencing (NGS) technology to identify pathogens from cell-free plasma DNA. In this study, 78 plasma samples from ICU patients were analyzed by both NGS and BC methods and verified by PCR amplification/Sanger sequencing and ten plasma samples from healthy volunteers were analyzed by NGS as negative controls to define or calibrate the threshold of the NGS methodology. Overall, 1578 suspected patient samples were found to contain bacteria or fungi by NGS, whereas ten patients were diagnosed by BC. Seven samples were diagnosed with bacterial or fungal infection both by NGS and BC. Among them, two samples were diagnosed with two types of bacteria by NGS, whereas one sample was diagnosed with two types of bacteria by BC, which increased the detectability of bacteria or fungi from 11 with BC to 17 with NGS. Most interestingly, 14 specimens were also diagnosed with viral infection by NGS. The overall diagnostic sensitivity was significantly increased from 12.82% (10/78) by BC alone to 30.77% (24/78) by NGS alone for ICU patients, which provides more useful information for establishing patient treatment plans. NGS technology can be applied to detect bacteria in clinical blood samples as an emerging diagnostic tool rich in information to determine the appropriate treatment of septic patients. Copyright © 2016 IMSS. Published by Elsevier Inc. All rights reserved.

New Trends in Impedimetric Biosensors for the Detection of Foodborne Pathogenic Bacteria

PubMed Central

Wang, Yixian; Ye, Zunzhong; Ying, Yibin

2012-01-01

The development of a rapid, sensitive, specific method for the foodborne pathogenic bacteria detection is of great importance to ensure food safety and security. In recent years impedimetric biosensors which integrate biological recognition technology and impedance have gained widespread application in the field of bacteria detection. This paper presents an overview on the progress and application of impedimetric biosensors for detection of foodborne pathogenic bacteria, particularly the new trends in the past few years, including the new specific bio-recognition elements such as bacteriophage and lectin, the use of nanomaterials and microfluidics techniques. The applications of these new materials or techniques have provided unprecedented opportunities for the development of high-performance impedance bacteria biosensors. The significant developments of impedimetric biosensors for bacteria detection in the last five years have been reviewed according to the classification of with or without specific bio-recognition element. In addition, some microfluidics systems, which were used in the construction of impedimetric biosensors to improve analytical performance, are introduced in this review. PMID:22737018

Virus-Bacteria Interactions: Implications and Potential for the Applied and Agricultural Sciences.

PubMed

Moore, Matthew D; Jaykus, Lee-Ann

2018-02-02

Eukaryotic virus-bacteria interactions have recently become an emerging topic of study due to multiple significant examples related to human pathogens of clinical interest. However, such omnipresent and likely important interactions for viruses and bacteria relevant to the applied and agricultural sciences have not been reviewed or compiled. The fundamental basis of this review is that these interactions have importance and deserve more investigation, as numerous potential consequences and applications arising from their discovery are relevant to the applied sciences. The purpose of this review is to highlight and summarize eukaryotic virus-bacteria findings in the food/water, horticultural, and animal sciences. In many cases in the agricultural sciences, mechanistic understandings of the effects of virus-bacteria interactions remain unstudied, and many studies solely focus on co-infections of bacterial and viral pathogens. Given recent findings relative to human viral pathogens, further research related to virus-bacteria interactions would likely result in numerous discoveries and beneficial applications.

The bacteriology of children prior to 1st stage autologous ear reconstruction.

PubMed

Eley, Karen A; Gault, David T

2010-12-01

In virtually all surgical specialities the use of peri-operative antibiotic prophylaxis to minimise wound site infection is routine practice. Antibiotic selection is targeted towards the pathogens most commonly encountered at the surgical site. The surgical management of microtia is by autologous rib cartilage reconstruction, a process that involves at least two surgical stages. The pits and recesses of the microtia ear are difficult to clean and may shelter unusual pathogens not routinely found as skin commensals, requiring modified prophylaxis. This retrospective review of 37 patients undergoing 1st stage ear reconstruction, examines the pre-operative ear site, nose and throat swabs to determine the common pre-operative bacteria encountered in children prior to ear reconstruction, to aid in appropriate antibiotic selection. Copyright © 2010 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Correlation of Shiga Toxin Gene Frequency with Commonly Used Microbial Indicators of Recreational Water Quality▿ †

PubMed Central

Smith, Cody J.; Olszewski, Adam M.; Mauro, Steven A.

2009-01-01

Shiga toxin (Stx) genes produce proteins that are pathogenic to humans, leading to severe gastrointestinal illness. This work focuses on examining the abundance and distribution of stx genes in relation to common microbial indicators in beach water and streams in the vicinity of Presque Isle State Park in Erie, PA. By use of quantitative PCR, the relative abundance levels of stx DNA in over 700 samples in the sampling area were determined. The results demonstrate that the abundance and distribution of stx genes are variable and do not correlate with the abundance of Escherichia coli bacteria, enterococci, or viral particles. These results suggest that microbial indicators of water quality are not adequate in predicting the occurrence of organisms that harbor stx genes and highlight the need for standardized pathogen-specific detection protocols for waters utilized for recreational swimming. PMID:19011065

The influence of bacteria on multitrophic interactions among plants, psyllids, and pathogen.

PubMed

Tamborindeguy, Cecilia; Huot, Ordom Brian; Ibanez, Freddy; Levy, Julien

2017-12-01

The recent emergence of several plant diseases caused by psyllid-borne bacterial pathogens worldwide (Candidatus Liberibacter spp.) has created renewed interest on the interaction between psyllids and bacteria. In spite of these efforts to understand psyllid association with bacteria, many aspects of their interactions remain poorly understood. As more organisms are studied, subtleties on the molecular interactions as well as on the effects of the bacteria on the psyllid host are being uncovered. Additionally, psyllid-borne bacterial phytopathogens can also affect the host plant, which in turn can impact psyllid physiology and behavior. Here, we review the current literature on different aspects of the influence of bacteria on multitrophic interactions among plants, psyllids, and pathogens. We then highlight gaps that need to be addressed to advance this field, which can have significant implications for controlling these newly emergent and other plant diseases. © 2017 Institute of Zoology, Chinese Academy of Sciences.

The ability of selected plant essential oils to enhance the action of recommended antibiotics against pathogenic wound bacteria.

PubMed

Sienkiewicz, Monika; Łysakowska, Monika; Kowalczyk, Edward; Szymańska, Grażyna; Kochan, Ewa; Krukowska, Jolanta; Olszewski, Jurek; Zielińska-Bliźniewska, Hanna

2017-03-01

The aim of this work was to characterize the ability of essential oils to support antibiotics against pathogenic bacteria in wounds. Gram-positive and Gram-negative bacteria obtained from wound infections were identified according to standard microbiological methods. Essential oils were analysed by GC-FID-MS. The susceptibility of bacteria to antibiotics, essential oils and their combination was assessed using the disc-diffusion method. The Minimal Inhibitory Concentration and Minimum Bactericidal Concentration of the essential oils were established by the micro-dilution broth method. Although cinnamon, clove, thyme and lavender essential oils were found to have the greatest antibacterial activity when used alone, the greatest additive and synergistic effects against pathogenic wound bacteria in combination with recommended antibiotics were demonstrated by basil, clary sage and rosemary oils. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Bacteria-bacteria interactions within the microbiota of the ancestral metazoan Hydra contribute to fungal resistance.

PubMed

Fraune, Sebastian; Anton-Erxleben, Friederike; Augustin, René; Franzenburg, Sören; Knop, Mirjam; Schröder, Katja; Willoweit-Ohl, Doris; Bosch, Thomas C G

2015-07-01

Epithelial surfaces of most animals are colonized by diverse microbial communities. Although it is generally agreed that commensal bacteria can serve beneficial functions, the processes involved are poorly understood. Here we report that in the basal metazoan Hydra, ectodermal epithelial cells are covered with a multilayered glycocalyx that provides a habitat for a distinctive microbial community. Removing this epithelial microbiota results in lethal infection by the filamentous fungus Fusarium sp. Restoring the complex microbiota in gnotobiotic polyps prevents pathogen infection. Although mono-associations with distinct members of the microbiota fail to provide full protection, additive and synergistic interactions of commensal bacteria are contributing to full fungal resistance. Our results highlight the importance of resident microbiota diversity as a protective factor against pathogen infections. Besides revealing insights into the in vivo function of commensal microbes in Hydra, our findings indicate that interactions among commensal bacteria are essential to inhibit pathogen infection.

Microbial source tracking in impaired watersheds using PhyloChip and machine-learning classification.

PubMed

Dubinsky, Eric A; Butkus, Steven R; Andersen, Gary L

2016-11-15

Sources of fecal indicator bacteria are difficult to identify in watersheds that are impacted by a variety of non-point sources. We developed a molecular source tracking test using the PhyloChip microarray that detects and distinguishes fecal bacteria from humans, birds, ruminants, horses, pigs and dogs with a single test. The multiplexed assay targets 9001 different 25-mer fragments of 16S rRNA genes that are common to the bacterial community of each source type. Both random forests and SourceTracker were tested as discrimination tools, with SourceTracker classification producing superior specificity and sensitivity for all source types. Validation with 12 different mammalian sources in mixtures found 100% correct identification of the dominant source and 84-100% specificity. The test was applied to identify sources of fecal indicator bacteria in the Russian River watershed in California. We found widespread contamination by human sources during the wet season proximal to settlements with antiquated septic infrastructure and during the dry season at beaches during intense recreational activity. The test was more sensitive than common fecal indicator tests that failed to identify potential risks at these sites. Conversely, upstream beaches and numerous creeks with less reliance on onsite wastewater treatment contained no fecal signal from humans or other animals; however these waters did contain high counts of fecal indicator bacteria after rain. Microbial community analysis revealed that increased E. coli and enterococci at these locations did not co-occur with common fecal bacteria, but rather co-varied with copiotrophic bacteria that are common in freshwaters with high nutrient and carbon loading, suggesting runoff likely promoted the growth of environmental strains of E. coli and enterococci. These results indicate that machine-learning classification of PhyloChip microarray data can outperform conventional single marker tests that are used to assess health risks, and is an effective tool for distinguishing numerous fecal and environmental sources of pathogen indicators. Copyright © 2016 Elsevier Ltd. All rights reserved.

Early identification of microorganisms in blood culture prior to the detection of a positive signal in the BACTEC FX system using matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

PubMed

Wang, Ming-Cheng; Lin, Wei-Hung; Yan, Jing-Jou; Fang, Hsin-Yi; Kuo, Te-Hui; Tseng, Chin-Chung; Wu, Jiunn-Jong

2015-08-01

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is a valuable method for rapid identification of blood stream infection (BSI) pathogens. Integration of MALDI-TOF MS and blood culture system can speed the identification of causative BSI microorganisms. We investigated the minimal microorganism concentrations of common BSI pathogens required for positive blood culture using BACTEC FX and for positive identification using MALDI-TOF MS. The time to detection with positive BACTEC FX and minimal incubation time with positive MALDI-TOF MS identification were determined for earlier identification of common BSI pathogens. The minimal microorganism concentrations required for positive blood culture using BACTEC FX were >10(7)-10(8) colony forming units/mL for most of the BSI pathogens. The minimal microorganism concentrations required for identification using MALDI-TOF MS were > 10(7) colony forming units/mL. Using simulated BSI models, one can obtain enough bacterial concentration from blood culture bottles for successful identification of five common Gram-positive and Gram-negative bacteria using MALDI-TOF MS 1.7-2.3 hours earlier than the usual time to detection in blood culture systems. This study provides an approach to earlier identification of BSI pathogens prior to the detection of a positive signal in the blood culture system using MALDI-TOF MS, compared to current methods. It can speed the time for identification of BSI pathogens and may have benefits of earlier therapy choice and on patient outcome. Copyright © 2013. Published by Elsevier B.V.

The secreted fructose 1,6-bisphosphate aldolase as a broad spectrum vaccine candidate against pathogenic bacteria in aquaculture.

PubMed

Sun, Zhongyang; Shen, Binbing; Wu, Haizhen; Zhou, Xiangyu; Wang, Qiyao; Xiao, Jingfan; Zhang, Yuanxing

2015-10-01

The development of aquaculture has been hampered by different aquatic pathogens that can cause edwardsiellosis, vibriosis, or other diseases. Therefore, developing a broad spectrum vaccine against different fish diseases is necessary. In this study, fructose 1,6-bisphosphate aldolase (FBA), a conserved enzyme in the glycolytic pathway, was demonstrated to be located in the non-cytoplasmic components of five aquatic pathogenic bacteria and exhibited remarkable protection and cross-protection against these pathogens in turbot and zebrafish. Further analysis revealed that sera sampled from vaccinated turbot had a high level of specific antibody and bactericidal activity against these pathogens. Meanwhile, the increased expressions of immune response-related genes associated with antigen recognition and presentation indicated that the adaptive immune response was effectively aroused. Taken together, our results suggest that FBA can be utilized as a broad-spectrum vaccine against various pathogenic bacteria of aquaculture in the future. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantifying school officials' exposure to bacterial pathogens at graduation ceremonies using repeated observational measures.

PubMed

Bishai, David; Liu, Liang; Shiau, Stephanie; Wang, Harrison; Tsai, Cindy; Liao, Margaret; Prakash, Shivaani; Howard, Tracy

2011-06-01

The purpose of this study was to estimate the risk of acquiring pathogenic bacteria as a result of shaking hands at graduation ceremonies. School officials participating in graduation ceremonies at elementary, secondary, and postsecondary schools were recruited. Specimens were collected before and immediately following graduation. Cultures identified any pathogenic bacteria in each specimen. Subjects shook a total of 5,209 hands. Staphylococcus aureus was separately detected on one pregraduation right hand, one postgraduation right hand, and one postgraduation left hand. Nonpathogenic bacteria were collected in 93% of specimens. Pregraduation and postgraduation specimens were of different strains. We measured a risk of one new bacterial acquisition in a sample exposed to 5,209 handshakes yielding an overall estimate of 0.019 pathogens acquired per handshake. We conclude that a single handshake at a graduation offers only a small risk of bacterial pathogen acquisition.

Spreading of infectious materials from the laser interaction zone: viruses and bacteria

NASA Astrophysics Data System (ADS)

Weber, Lothar W.

1996-12-01

Actual occupational infections of medical staff is dominated by HBV, HIV and HCV-infections by dermal blood inoculation like needle injuries. What amount of these blood borne infections was possibly done via the aerosol pathway is unknown today. Looking at the laser generated aerodynamic particle sizes and the particle size of human pathogen viruses as circulating or cell fixed units shows common transmission abilities to the human respiratory system. In cell tissue monolayer model systems and contaminated serum systems with virus infections this mechanics were demonstrated as viable. For safety evaluation, the lifetime, spreading behavior and infection potential by viruses and bacterias of contaminated human laser aerosol must be further characterized.

PathogenFinder--distinguishing friend from foe using bacterial whole genome sequence data.

PubMed

Cosentino, Salvatore; Voldby Larsen, Mette; Møller Aarestrup, Frank; Lund, Ole

2013-01-01

Although the majority of bacteria are harmless or even beneficial to their host, others are highly virulent and can cause serious diseases, and even death. Due to the constantly decreasing cost of high-throughput sequencing there are now many completely sequenced genomes available from both human pathogenic and innocuous strains. The data can be used to identify gene families that correlate with pathogenicity and to develop tools to predict the pathogenicity of newly sequenced strains, investigations that previously were mainly done by means of more expensive and time consuming experimental approaches. We describe PathogenFinder (http://cge.cbs.dtu.dk/services/PathogenFinder/), a web-server for the prediction of bacterial pathogenicity by analysing the input proteome, genome, or raw reads provided by the user. The method relies on groups of proteins, created without regard to their annotated function or known involvement in pathogenicity. The method has been built to work with all taxonomic groups of bacteria and using the entire training-set, achieved an accuracy of 88.6% on an independent test-set, by correctly classifying 398 out of 449 completely sequenced bacteria. The approach here proposed is not biased on sets of genes known to be associated with pathogenicity, thus the approach could aid the discovery of novel pathogenicity factors. Furthermore the pathogenicity prediction web-server could be used to isolate the potential pathogenic features of both known and unknown strains.

Bacteremias in liver transplant recipients: shift toward gram-negative bacteria as predominant pathogens.

PubMed

Singh, Nina; Wagener, Marilyn M; Obman, Asia; Cacciarelli, Thomas V; de Vera, Michael E; Gayowski, Timothy

2004-07-01

During the 1990s, gram-positive bacteria emerged as major pathogens after liver transplantation. We sought to determine whether the pathogens associated with bacteremias in liver transplant recipients have changed. Patients included 233 liver transplant recipients transplanted between 1989 and 2003. The proportion of all infections due to bacteremias increased significantly over time (P <.0001). Of other major infections, a trend toward a decrease in fungal infections (P =.089) and a significant decrease in cytomegalovirus (CMV) disease (P =.0004) were documented. Whereas the proportion of bacteremias due to gram-negatives increased from 25% in the period of 1989-1993 to 51.8% in 1998-03, that of gram-positive bacteria decreased from 75% in the period of 1989-93 to 48.2% in the period of 1998-2003. Methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequent pathogens in bacteremic patients. The incidence of bacteremias due to MRSA and Pseudomonas aeruginosa has remained unchanged (P <.20); however, that due to enteric gram-negative bacteria, particularly Klebsiella pneumoniae has increased (P =.02). Klebsiella pneumoniae isolates in the current quartile were not clonally related. In conclusion, bacteremias as a proportion of all infections in liver transplant recipients have increased significantly over time, due in part to a decline in infections due to other major pathogens, e.g., fungi, primarily Candida species, and CMV. Gram-negative bacteria have emerged as predominant pathogens in bacteremic liver transplant recipients.

Agrochemicals indirectly increase survival of E. coli O157:H7 and indicator bacteria by reducing ecosystem services.

PubMed

Staley, Zachery R; Rohr, Jason R; Senkbeil, Jacob K; Harwood, Valerie J

Storm water and agricultural runoff frequently contain agrochemicals, fecal indicator bacteria (FIB), and zoonotic pathogens. Entry of such contaminants into aquatic ecosystems may affect ecology and human health. This study tested the hypothesis that the herbicide atrazine and the fungicide chlorothalonil indirectly affect the survival of FIB (Escherichia coli and Enterococcus faecalis) and a pathogen (E. coli O157:H7) by altering densities of protozoan predators or by altering competition from autochthonous bacteria. Streptomycin-resistant E. coli, En. faecalis, and E. coli O157:H7 were added to microcosms composed of Florida river water containing natural protozoan and bacterial populations. FIB, pathogen, and protozoan densities were monitored over six days. Known metabolic inhibitors, cycloheximide and streptomycin, were used to inhibit autochthonous protozoa or bacteria, respectively. The inhibitors made it possible to isolate the effects of predation or competition on survival of allochthonous bacteria, and each treatment increased the survival of FIB and pathogens. Chlorothalonil's effect was similar to that of cycloheximide, significantly reducing protozoan densities and elevating densities of FIB and pathogens relative to the control. Atrazine treatment did not affect protozoan densities, but, through an effect on competition, resulted in significantly greater densities of En. faecalis and E. coli O157:H7. Hence, by reducing predaceous protozoa and bacterial competitors that facilitate purifying water bodies of FIBs and human pathogens, chlorothalonil and atrazine indirectly diminished an ecosystem service of fresh water.

Aerobic salivary bacteria in wild and captive Komodo dragons.

PubMed

Montgomery, Joel M; Gillespie, Don; Sastrawan, Putra; Fredeking, Terry M; Stewart, George L

2002-07-01

During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive species of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were positive for both Gram-negative and Gram-positive bacteria. The average number of bacterial species within the saliva of wild dragons was 46% greater than for captive dragons. While Escherichia coli was the most common bacterium isolated from the saliva of wild dragons, this species was not present in captive dragons. The most common bacteria isolated from the saliva of captive dragons were Staphylococcus capitis and Staphylococcus capitis and Staphylococcus caseolyticus, neither of which were found in wild dragons. High mortality was seen among mice injected with saliva from wild dragons and the only bacterium isolated from the blood of dying mice was Pasteurella multocida. A competitive inhibition enzyme-linked immunosorbent assay revealed the presence of anti-Pasteurella antibody in the plasma of Komodo dragons. Four species of bacteria isolated from dragon saliva showed resistance to one or more of 16 antimicrobics tested. The wide variety of bacteria demonstrated in the saliva of the Komodo dragon in this study, at least one species of which was highly lethal in mice and 54 species of which are known pathogens, support the observation that wounds inflicted by this animal are often associated with sepsis and subsequent bacteremia in prey animals.

High-throughput DNA microarray detection of pathogenic bacteria in shallow well groundwater in the Kathmandu Valley, Nepal.

PubMed

Inoue, Daisuke; Hinoura, Takuji; Suzuki, Noriko; Pang, Junqin; Malla, Rabin; Shrestha, Sadhana; Chapagain, Saroj Kumar; Matsuzawa, Hiroaki; Nakamura, Takashi; Tanaka, Yasuhiro; Ike, Michihiko; Nishida, Kei; Sei, Kazunari

2015-01-01

Because of heavy dependence on groundwater for drinking water and other domestic use, microbial contamination of groundwater is a serious problem in the Kathmandu Valley, Nepal. This study investigated comprehensively the occurrence of pathogenic bacteria in shallow well groundwater in the Kathmandu Valley by applying DNA microarray analysis targeting 941 pathogenic bacterial species/groups. Water quality measurements found significant coliform (fecal) contamination in 10 of the 11 investigated groundwater samples and significant nitrogen contamination in some samples. The results of DNA microarray analysis revealed the presence of 1-37 pathogen species/groups, including 1-27 biosafety level 2 ones, in 9 of the 11 groundwater samples. While the detected pathogens included several feces- and animal-related ones, those belonging to Legionella and Arthrobacter, which were considered not to be directly associated with feces, were detected prevalently. This study could provide a rough picture of overall pathogenic bacterial contamination in the Kathmandu Valley, and demonstrated the usefulness of DNA microarray analysis as a comprehensive screening tool of a wide variety of pathogenic bacteria.

Neither non-toxigenic Staphylococcus aureus nor commensal S. epidermidi activates NLRP3 inflammasomes in human conjunctival goblet cells

PubMed Central

Li, Dayu; Hodges, Robin R; Bispo, Paulo; Gilmore, Michael S; Gregory-Ksander, Meredith; Dartt, Darlene A

2017-01-01

Purpose The conjunctiva is a wet mucosal surface surrounding the cornea that is continuously exposed to pathogens. Nevertheless, persistent inflammation is not observed. We examined if the NOD-like receptor pyrin domain 3 (NLRP3) inflammasome functions as a sensor that distinguishes commensal and non-pathogenic bacteria from pathogenic bacteria in human conjunctival goblet cells. Methods Goblet cells were grown from human conjunctiva and co-cultured with commensal Staphylococcus epidermidis, isogenic non-toxigenic S. aureus ACL135 and as a control toxigenic S. aureus RN6390. Activation of the NLRP3 inflammasome was determined by measuring changes in NF-κB activity, expression of pro-interleukin (IL)-1β and NLRP3, activation of caspase-1 and secretion of mature IL-1β. Goblet cell mucin secretion was measured in parallel. Results While all three strains of bacteria were able to bind to goblet cells, neither commensal S. epidermidis nor isogenic non-toxigenic S. aureus ACL135 was able to stimulate an increase in (1) NF-κB activity, (2) pro-IL-1β and NLRP3 expression, (3) caspase-1 activation, (4) mature IL-1β and (5) mucin secretion. Toxigenic S. aureus, the positive control, increased these values: knockdown of NLRP3 with small interfering RNA (siRNA) completely abolished the toxigenic S. aureus-induced expression of pro-IL-1β and secretion of mature IL-1β. Conclusions We conclude that NLRP3 serves as a sensor capable of discriminating commensal and non-pathogenic bacteria from pathogenic bacteria in conjunctival goblet cells, and that activation of the NLRP3 inflammasome induced by pathogenic bacteria mediates secretion of both mature IL-1β and large secretory mucins from these cells. PMID:29354725

Raft-Like Membrane Domains in Pathogenic Microorganisms

PubMed Central

Farnoud, Amir M.; Toledo, Alvaro M.; Konopka, James B.; Del Poeta, Maurizio; London, Erwin

2016-01-01

The lipid bilayer of the plasma membrane is thought to be compartmentalized by the presence of lipid-protein microdomains. In eukaryotic cells, microdomains composed of sterols and sphingolipids packed in a liquid-ordered state, commonly known as lipid rafts, are believed to exist. While less studied in bacterial cells, reports on the presence of sterol or protein-mediated microdomains in bacterial cell membranes are also appearing with increasing frequency. Recent efforts have been focused on addressing the biophysical and biochemical properties of lipid rafts. However, most studies have been focused on synthetic membranes, mammalian cells, and/or model, non-pathogenic microorganisms. Much less is known about microdomains in the plasma membrane of pathogenic microorganisms. This review attempts to provide an overview of the current state of knowledge of lipid rafts in pathogenic fungi and the developing field of microdomains in pathogenic bacteria. The current literature on the structure and function and of microdomains is reviewed and the potential role of microdomains in growth, pathogenesis, and drug resistance of pathogens are discussed. Better insight into the structure and function of membrane microdomains in pathogenic microorganisms might lead to a better understanding of the process of pathogenesis and development of raft-mediated approaches for new methods of therapy. PMID:26015285

Evaluation of invertebrate infection models for pathogenic corynebacteria.

PubMed

Ott, Lisa; McKenzie, Ashleigh; Baltazar, Maria Teresa; Britting, Sabine; Bischof, Andrea; Burkovski, Andreas; Hoskisson, Paul A

2012-08-01

For several pathogenic bacteria, model systems for host-pathogen interactions were developed, which provide the possibility of quick and cost-effective high throughput screening of mutant bacteria for genes involved in pathogenesis. A number of different model systems, including amoeba, nematodes, insects, and fish, have been introduced, and it was observed that different bacteria respond in different ways to putative surrogate hosts, and distinct model systems might be more or less suitable for a certain pathogen. The aim of this study was to develop a suitable invertebrate model for the human and animal pathogens Corynebacterium diphtheriae, Corynebacterium pseudotuberculosis, and Corynebacterium ulcerans. The results obtained in this study indicate that Acanthamoeba polyphaga is not optimal as surrogate host, while both Caenorhabtitis elegans and Galleria larvae seem to offer tractable models for rapid assessment of virulence between strains. Caenorhabtitis elegans gives more differentiated results and might be the best model system for pathogenic corynebacteria, given the tractability of bacteria and the range of mutant nematodes available to investigate the host response in combination with bacterial virulence. Nevertheless, Galleria will also be useful in respect to innate immune responses to pathogens because insects offer a more complex cell-based innate immune system compared with the simple innate immune system of C. elegans. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Identification of DNA Methyltransferase Genes in Human Pathogenic Bacteria by Comparative Genomics.

PubMed

Brambila-Tapia, Aniel Jessica Leticia; Poot-Hernández, Augusto Cesar; Perez-Rueda, Ernesto; Rodríguez-Vázquez, Katya

2016-06-01

DNA methylation plays an important role in gene expression and virulence in some pathogenic bacteria. In this report, we describe DNA methyltransferases (MTases) present in human pathogenic bacteria and compared them with related species, which are not pathogenic or less pathogenic, based in comparative genomics. We performed a search in the KEGG database of the KEGG database orthology groups associated with adenine and cytosine DNA MTase activities (EC: 2.1.1.37, EC: 2.1.1.113 and EC: 2.1.1.72) in 37 human pathogenic species and 18 non/less pathogenic relatives and performed comparisons of the number of these MTases sequences according to their genome size, the DNA MTase type and with their non-less pathogenic relatives. We observed that Helicobacter pylori and Neisseria spp. presented the highest number of MTases while ten different species did not present a predicted DNA MTase. We also detected a significant increase of adenine MTases over cytosine MTases (2.19 vs. 1.06, respectively, p < 0.001). Adenine MTases were the only MTases associated with restriction modification systems and DNA MTases associated with type I restriction modification systems were more numerous than those associated with type III restriction modification systems (0.84 vs. 0.17, p < 0.001); additionally, there was no correlation with the genome size and the total number of DNA MTases, indicating that the number of DNA MTases is related to the particular evolution and lifestyle of specific species, regulating the expression of virulence genes in some pathogenic bacteria.

Mechanisms of Drug Resistance: Daptomycin Resistance

PubMed Central

Tran, Truc T.; Munita, Jose M.; Arias, Cesar A.

2016-01-01

Daptomycin (DAP) is a cyclic lipopeptide with in vitro activity against a variety of Gram-positive pathogens, including multidrug-resistant organisms. Since its introduction in clinical practice in 2003, DAP has become an important key front-line antibiotic for severe or deep-seated infections caused by Gram-positive organisms. Unfortunately, DAP-resistance (R) has been extensively documented in clinically important organisms such as Staphylococcus aureus, Enterococcus spp, and Streptococcus spp. Studies on the mechanisms of DAP-R in Bacillus subtilis and other Gram-positive bacteria indicate that the genetic pathways of DAP resistance are diverse and complex. However, a common phenomenon emerging from these mechanistic studies is that DAP-R is associated with important adaptive changes in cell wall and cell membrane homeostasis with critical changes in cell physiology. Findings related to these adaptive changes have offered novel insights into the genetics and molecular mechanisms of bacterial cell envelope stress response and the manner in which Gram-positive bacteria cope with the antimicrobial peptide attack and protect vital structures of the cell envelope such as the cell membrane. In this review, we will examine the most recent findings related to the molecular mechanisms of resistance to DAP in relevant Gram-positive pathogens and discuss the clinical implications for therapy against these important bacteria. PMID:26495887

Virulence of entomopathogenic bacteria in the bed bug, Cimex lectularius.

PubMed

Pietri, Jose E; Liang, Dangsheng

2018-01-01

Due in part to the development of insecticide resistance, the common bed bug, Cimex lectularius, has overcome human intervention efforts to make a global resurgence. The failure of chemical pesticides has created a need for novel strategies to combat bed bugs. While a number of insect pests are susceptible to the use of entomopathogenic microbes or microbial-derived toxins, biological control methods have not been thoroughly explored in bed bugs. Here, we tested the virulence of three entomopathogenic bacterial species in C. lectularius to determine their potential for bed bug control. We examined bed bug survival after inoculation with live or heat-killed Serratia marcescens, Pseudomonas fluorescens, and Bacillus thuringiensis israelensis at varying temperatures. We also analyzed the viability and growth of the same bacteria in infected bed bugs. All three bacterial species were pathogenic to bed bugs. However, the effects of S. marcescens and P. fluorescens were temperature-dependent while the lethality of B. thuringiensis israelensis was not. In addition, bacterial virulence was partly dependent on the route of infection but was not strongly associated with proliferation. Thus, our results suggest multiple possible mechanisms of microbial pathogenicity in the bed bug and indicate that entomopathogenic bacteria, or products derived from them, may have useful applications for bed bug control. Copyright © 2017 Elsevier Inc. All rights reserved.

What Healthcare Workers Should Know about Environmental Bacterial Contamination in the Intensive Care Unit.

PubMed

Russotto, Vincenzo; Cortegiani, Andrea; Fasciana, Teresa; Iozzo, Pasquale; Raineri, Santi Maurizio; Gregoretti, Cesare; Giammanco, Anna; Giarratano, Antonino

2017-01-01

Intensive care unit- (ICU-) acquired infections are a major health problem worldwide. Inanimate surfaces and equipment contamination may play a role in cross-transmission of pathogens and subsequent patient colonization or infection. Bacteria contaminate inanimate surfaces and equipment of the patient zone and healthcare area, generating a reservoir of potential pathogens, including multidrug resistant species. Traditional terminal cleaning methods have limitations. Indeed patients who receive a bed from prior patient carrying bacteria are exposed to an increased risk (odds ratio 2.13, 95% confidence intervals 1.62-2.81) of being colonized and potentially infected by the same bacterial species of the previous patient. Biofilm formation, even on dry surfaces, may play a role in reducing the efficacy of terminal cleaning procedures since it enables bacteria to survive in the environment for a long period and provides increased resistance to commonly used disinfectants. No-touch methods (e.g., UV-light, hydrogen peroxide vapour) are under investigation and further studies with patient-centred outcomes are needed, before considering them the standard of terminal cleaning in ICUs. Healthcare workers should be aware of the role of environmental contamination in the ICU and consider it in the broader perspective of infection control measures and stewardship initiatives.

Analysis of the Bacterial Diversity in Liver Abscess: Differences between Pyogenic and Amebic Abscesses

PubMed Central

Reyna-Fabián, Miriam E.; Zermeño, Valeria; Ximénez, Cecilia; Flores, Janin; Romero, Miguel F.; Diaz, Daniel; Argueta, Jesús; Moran, Patricia; Valadez, Alicia; Cerritos, René

2016-01-01

Several recent studies have demonstrated that virulence in Entamoeba histolytica is triggered in the presence of both pathogenic and nonpathogenic bacteria species using in vitro and in vivo experimental animal models. In this study, we examined samples aspirated from abscess material obtained from patients who were clinically diagnosed with amebic liver abscess (ALA) or pyogenic liver abscess (PLA). To determine the diversity of bacterial species in the abscesses, we performed partial 16S rRNA gene sequencing. In addition, the E. histolytica and Entamoeba dispar species were genotyped using tRNA-linked short tandem repeats as specific molecular markers. The association between clinical data and bacterial and parasite genotypes were examined through a correspondence analysis. The results showed the presence of numerous bacterial groups. These taxonomic groups constitute common members of the gut microbiota, although all of the detected bacterial species have a close phylogenetic relationship with bacterial pathogens. Furthermore, some patients clinically diagnosed with PLA and ALA were coinfected with E. dispar or E. histolytica, which suggests that the virulence of these parasites increased in the presence of bacteria. However, no specific bacterial groups were associated with this effect. Together, our results suggest a nonspecific mechanism of virulence modulation by bacteria in Entamoeba. PMID:26572872

Immunomodulatory role for membrane vesicles released by THP-1 macrophages and respiratory pathogens during macrophage infection.

PubMed

Volgers, Charlotte; Benedikter, Birke J; Grauls, Gert E; Savelkoul, Paul H M; Stassen, Frank R M

2017-11-13

During infection, inflammation is partially driven by the release of mediators which facilitate intercellular communication. Amongst these mediators are small membrane vesicles (MVs) that can be released by both host cells and Gram-negative and -positive bacteria. Bacterial membrane vesicles are known to exert immuno-modulatory and -stimulatory actions. Moreover, it has been proposed that host cell-derived vesicles, released during infection, also have immunostimulatory properties. In this study, we assessed the release and activity of host cell-derived and bacterial MVs during the first hours following infection of THP-1 macrophages with the common respiratory pathogens non-typeable Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, and Pseudomonas aeruginosa. Using a combination of flow cytometry, tunable resistive pulse sensing (TRPS)-based analysis and electron microscopy, we demonstrated that the release of MVs occurs by both host cells and bacteria during infection. MVs released during infection and bacterial culture were found to induce a strong pro-inflammatory response by naive THP-1 macrophages. Yet, these MVs were also found to induce tolerance of host cells to secondary immunogenic stimuli and to enhance bacterial adherence and the number of intracellular bacteria. Bacterial MVs may play a dual role during infection, as they can both trigger and dampen immune responses thereby contributing to immune defence and bacterial survival.

Mossambicus tilapia (Oreochromis mossambicus) collected from water bodies impacted by urban waste carries extended-spectrum beta-lactamases and integron-bearing gut bacteria.

PubMed

Marathe, Nachiket P; Gaikwad, Swapnil S; Vaishampayan, Ankita A; Rasane, Mandar H; Shouche, Yogesh S; Gade, Wasudev N

2016-09-01

Oreochromis mossambicus (Peters 1852) (Tilapia) is one of the most consumed fish globally. Tilapia thrives well in environments polluted by urban waste, which invariably contain antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). Thus, Tilapia surviving in such polluted environments may serve as a potential source for dissemination of ARGs. To investigate this, we isolated bacterial strains from gut of Tilapia found in polluted rivers and lakes near Pune, India, and studied the prevalence of resistance genes by molecular methods. A total of 91 bacterial strains were obtained, which include fish pathogens and human pathogens such as Aeromonas hydrophila, Klebsiella pneumoniae, E. coli, Serratia marcescens, Enterobacter spp. and Shigella spp. Overall the prevalence of class 1 integrons, class 2 integrons, extended-spectrum betalactamases (ESBLs) blaCTX-M, blaSHV and aac(6')-Ib-cr gene was 38 percent, 24 percent, 38 percent, 31 percent and 31 percent respectively. Forty-two percent of the Enterobacteriaceae strains carried blaCTX-M gene, which is a common ESBL gene in clinics. The study demonstrates that tilapia found in the polluted waters can serve as reservoirs and an alternative route for human exposure to clinically important ARG-carrying bacteria. The consumption and handling of these fish may pose a potential health risk.

Surface immuno-functionalisation for the capture and detection of Vibrio species in the marine environment: a new management tool for industrial facilities.

PubMed

Laczka, Olivier F; Labbate, Maurizio; Seymour, Justin R; Bourne, David G; Fielder, Stewart S; Doblin, Martina A

2014-01-01

Bacteria from the genus Vibrio are a common and environmentally important group of bacteria within coastal environments and include species pathogenic to aquaculture organisms. Their distribution and abundance are linked to specific environmental parameters, including temperature, salinity and nutrient enrichment. Accurate and efficient detection of Vibrios in environmental samples provides a potential important indicator of overall ecosystem health while also allowing rapid management responses for species pathogenic to humans or species implicated in disease of economically important aquacultured fish and invertebrates. In this study, we developed a surface immuno-functionalisation protocol, based on an avidin-biotin type covalent binding strategy, allowing specific sandwich-type detection of bacteria from the Vibrio genus. The assay was optimized on 12 diverse Vibrio strains, including species that have implications for aquaculture industries, reaching detection limits between 7×10(3) to 3×10(4) cells mL(-1). Current techniques for the detection of total Vibrios rely on laborious or inefficient analyses resulting in delayed management decisions. This work represents a novel approach for a rapid, accurate, sensitive and robust tool for quantifying Vibrios directly in industrial systems and in the environment, thereby facilitating rapid management responses.

Selection of Surrogate Bacteria for Use in Food Safety Challenge Studies: A Review.

PubMed

Hu, Mengyi; Gurtler, Joshua B

2017-09-01

Nonpathogenic surrogate bacteria are prevalently used in a variety of food challenge studies in place of foodborne pathogens such as Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Clostridium botulinum because of safety and sanitary concerns. Surrogate bacteria should have growth characteristics and/or inactivation kinetics similar to those of target pathogens under given conditions in challenge studies. It is of great importance to carefully select and validate potential surrogate bacteria when verifying microbial inactivation processes. A validated surrogate responds similar to the targeted pathogen when tested for inactivation kinetics, growth parameters, or survivability under given conditions in agreement with appropriate statistical analyses. However, a considerable number of food studies involving putative surrogate bacteria lack convincing validation sources or adequate validation processes. Most of the validation information for surrogates in these studies is anecdotal and has been collected from previous publications but may not be sufficient for given conditions in the study at hand. This review is limited to an overview of select studies and discussion of the general criteria and approaches for selecting potential surrogate bacteria under given conditions. The review also includes a list of documented bacterial pathogen surrogates and their corresponding food products and treatments to provide guidance for future studies.

Case-control study of diarrheal disease etiology in individuals over 5 years in southwest China.

PubMed

Zhang, Shun-Xian; Yang, Chun-Li; Gu, Wen-Peng; Ai, Lin; Serrano, Emmanuel; Yang, Pin; Zhou, Xia; Li, Shi-Zhu; Lv, Shan; Dang, Zhi-Sheng; Chen, Jun-Hu; Hu, Wei; Tian, Li-Guang; Chen, Jia-Xu; Zhou, Xiao-Nong

2016-01-01

Acute diarrhea is one of the major public health problems worldwide. Most of studies on acute diarrhea have been made on infants aged below 5 years and few efforts have been made to identify the etiological agents of acute diarrhea in people over five, especially in China. 271 diarrhea cases and 149 healthy controls over 5 years were recruited from four participating hospitals between June 2014 and July 2015. Each stool specimen was collected to detect a series of enteric pathogens, involving five viruses ( Rotavirus group A, RVA; Norovirus , NoV; Sapovirus , SaV; Astrovirus , As; and Adenovirus , Ad), seven bacteria (diarrheagenic Escherichia coli , DEC; non-typhoidal Salmonella , NTS; Shigella spp.; Vibrio cholera; Vibrio parahaemolyticus ; Aeromonas spp.; and Plesiomonas spp.) and three protozoa ( Cryptosporidium spp., Giardia lamblia, G. lamblia , and Blastocystis hominis, B. hominis ). Standard microbiological and molecular methods were applied to detect these pathogens. Data was analyzed using Chi square, Fisher-exact tests and logistic regressions. The prevalence of at least one enteric pathogen was detected in 29.2% (79/271) acute diarrhea cases and in 12.1% (18/149) in healthy controls ( p  < 0.0001). Enteric viral infections (14.4%) were the most common in patients suffering from acute diarrhea, followed by bacteria (13.7%) and intestinal protozoa (4.8%). DEC (12.5%) was the most common causative agent in diarrhea cases, followed by NoV GII (10.0%), RVA (7.4%) and B. hominis (4.8%). The prevalence of co-infection was statistically higher ( p  = 0.0059) in the case group (7.7%) than in the healthy control (1.3%). RVA-NoV GII (3.0%) was the most common co-infection in symptomatic cases. DEC was the most predominant pathogen in diarrhea cases, but it was largely overlooked because the lack of laboratory capacities. Because of the high prevalence of co-infections, it is recommended the urgent development of alternative laboratory methods to assess polymicrobial infections. Such methodological improvements will result in a better prevention and treatment strategies to control diarrhea illness in China.

Socioeconomic and Behavioral Factors Leading to Acquired Bacterial Resistance to Antibiotics in Developing Countries

PubMed Central

Okeke, Iruka N.; Lamikanra, Adebayo

1999-01-01

In developing countries, acquired bacterial resistance to antimicrobial agents is common in isolates from healthy persons and from persons with community-acquired infections. Complex socioeconomic and behavioral factors associated with antibiotic resistance, particularly regarding diarrheal and respiratory pathogens, in developing tropical countries, include misuse of antibiotics by health professionals, unskilled practitioners, and laypersons; poor drug quality; unhygienic conditions accounting for spread of resistant bacteria; and inadequate surveillance. PMID:10081668

Food provisioning alters infection dynamics in populations of a wild rodent.

PubMed

Forbes, Kristian M; Henttonen, Heikki; Hirvelä-Koski, Varpu; Kipar, Anja; Mappes, Tapio; Stuart, Peter; Huitu, Otso

2015-10-07

While pathogens are often assumed to limit the growth of wildlife populations, experimental evidence for their effects is rare. A lack of food resources has been suggested to enhance the negative effects of pathogen infection on host populations, but this theory has received little investigation. We conducted a replicated two-factor enclosure experiment, with introduction of the bacterium Bordetella bronchiseptica and food supplementation, to evaluate the individual and interactive effects of pathogen infection and food availability on vole populations during a boreal winter. We show that prior to bacteria introduction, vole populations were limited by food availability. Bordetella bronchiseptica introduction then reduced population growth and abundance, but contrary to predictions, primarily in food supplemented populations. Infection prevalence and pathological changes in vole lungs were most common in food supplemented populations, and are likely to have resulted from increased congregation and bacteria transmission around feeding stations. Bordetella bronchiseptica-infected lungs often showed protozoan co-infection (consistent with Hepatozoon erhardovae), together with more severe inflammatory changes. Using a multidisciplinary approach, this study demonstrates a complex picture of interactions and underlying mechanisms, leading to population-level effects. Our results highlight the potential for food provisioning to markedly influence disease processes in wildlife mammal populations. © 2015 The Author(s).

[Analysis of different pipe corrosion by ESEM and bacteria identification by API in pilot distribution network].

PubMed

Wu, Qing; Zhao, Xinhua; Yu, Qing; Li, Jun

2008-07-01

To understand the corrosion of different material water supply pipelines and bacterium in drinking water and biofilms. A pilot distribution network was built and water quality detection was made on popular pipelines of galvanized iron pipe, PPR and ABS plastic pipes by ESEM (environmental scanning electron microscopy). Bacterium in drinking water and biofilms were identified by API Bacteria Identification System 10s and 20E (Biomerieux, France), and pathogenicity of bacterium were estimated. Galvanized zinc pipes were seriously corroded; there were thin layers on inner face of PPR and ABS plastic pipes. 10 bacterium (got from water samples) were identified by API10S, in which 7 bacterium were opportunistic pathogens. 21 bacterium (got from water and biofilms samples) were identified by API20E, in which 5 bacterium were pathogens and 11 bacterium were opportunistic pathogens and 5 bacteria were not reported for their pathogenicities to human beings. The bacterial water quality of drinking water distribution networks were not good. Most bacterium in drinking water and biofilms on the inner face of pipeline of the drinking water distribution network were opportunistic pathogens, it could cause serious water supply accident, if bacteria spread in suitable conditions. In the aspect of pipe material, old pipelines should be changed by new material pipes.

Coronafacoyl Phytotoxin Biosynthesis and Evolution in the Common Scab Pathogen Streptomyces scabiei

PubMed Central

Bown, Luke; Li, Yuting; Berrué, Fabrice; Verhoeven, Joost T. P.; Dufour, Suzanne C.

2017-01-01

ABSTRACT Coronafacoyl phytotoxins are an important family of plant toxins that are produced by several different phytopathogenic bacteria, including the gammaproteobacterium Pseudomonas syringae and the actinobacterium Streptomyces scabiei (formerly Streptomyces scabies). The phytotoxins consist of coronafacic acid (CFA) linked via an amide bond to different amino acids or amino acid derivatives. Previous work suggested that S. scabiei and P. syringae use distinct biosynthetic pathways for producing CFA, which is subsequently linked to its amino acid partner to form the complete phytotoxin. Here, we provide further evidence that the S. scabiei CFA biosynthetic pathway is novel by characterizing the role of CYP107AK1, a predicted cytochrome P450 that has no homologue in P. syringae. Deletion of the CYP107AK1 gene abolished production of coronafacoyl-isoleucine (CFA-Ile), the primary coronafacoyl phytotoxin produced by S. scabiei. Structural elucidation of accumulated biosynthetic intermediates in the ΔCYP107AK1 mutant indicated that CYP107AK1 is required for introducing the oxygen atom that ultimately forms the carbonyl group in the CFA backbone. The CYP107AK1 gene along with two additional genes involved in CFA-Ile biosynthesis in S. scabiei were found to be associated with putative CFA biosynthetic genes in other actinobacteria but not in other organisms. Analysis of the overall genetic content and organization of known and putative CFA biosynthetic gene clusters, together with phylogenetic analysis of the core biosynthetic genes, indicates that horizontal gene transfer has played an important role in the dissemination of the gene cluster and that rearrangement, insertion, and/or deletion events have likely contributed to the divergent biosynthetic evolution of coronafacoyl phytotoxins in bacteria. IMPORTANCE The ability of plants to defend themselves against invading pathogens relies on complex signaling pathways that are controlled by key phytohormones such as jasmonic acid (JA). Some phytopathogenic bacteria have evolved the ability to manipulate JA signaling in order to overcome host defenses by producing coronatine (COR), which functions as a potent JA mimic. COR and COR-like molecules, collectively referred to as coronafacoyl phytotoxins, are produced by several different plant-pathogenic bacteria, and this study provides supporting evidence that different biosynthetic pathways are utilized by different bacteria for production of these phytotoxins. In addition, our study provides a greater understanding of how coronafacoyl phytotoxin biosynthesis may have evolved in phylogenetically distinct bacteria, and we demonstrate that production of these compounds may be more widespread than previously recognized and that their role for the producing organism may not be limited to host-pathogen interactions. PMID:28754703

Do wheelchairs spread pathogenic bacteria within hospital walls?

PubMed

Peretz, Avi; Koiefman, Anna; Dinisman, Eleonora; Brodsky, Diana; Labay, Kozitta

2014-02-01

Transmission of nosocomial pathogens has been linked to transient colonization of health care workers, medical devices and other constituents of patients' environment. In this paper we present our findings concerning the presence of pathogenic bacteria on wheelchairs, and the possibility that wheelchairs constitute a reservoir of these bacteria and a means of spreading them. In this work we examined four wheelchairs, each from a different location: the internal medicine ward, the emergency department, the general surgery ward and wheelchair stockpile of the transportation unit of the hospital. The samples were collected and cultured on different media. Bacterial identification and antimicrobial sensitivity testing were carried out using accepted practices in the microbiology laboratory. We found that wheelchairs are contaminated with several pathogenic bacteria, among them antibiotic-resistant strains such as MRSA, Pseudomonas aeruginosa, Acinetobacter baumanni etc. Since there is no specific guideline protocol that deals with disinfection and cleaning frequency of wheelchairs in hospitals, we suggest each hospital to write one.

The use of colorimetric sensor arrays to discriminate between pathogenic bacteria.

PubMed

Lonsdale, Claire L; Taba, Brian; Queralto, Nuria; Lukaszewski, Roman A; Martino, Raymond A; Rhodes, Paul A; Lim, Sung H

2013-01-01

A colorimetric sensor array is a high-dimensional chemical sensor that is cheap, compact, disposable, robust, and easy to operate, making it a good candidate technology to detect pathogenic bacteria, especially potential bioterrorism agents like Yersinia pestis and Bacillus anthracis which feature on the Center for Disease Control and Prevention's list of potential biothreats. Here, a colorimetric sensor array was used to continuously monitor the volatile metabolites released by bacteria in solid media culture in an Advisory Committee on Dangerous Pathogen Containment Level 3 laboratory. At inoculum concentrations as low as 8 colony-forming units per plate, 4 different bacterial species were identified with 100% accuracy using logistic regression to classify the kinetic profile of sensor responses to culture headspace gas. The sensor array was able to further discriminate between different strains of the same species, including 5 strains of Yersinia pestis and Bacillus anthracis. These preliminary results suggest that disposable colorimetric sensor arrays can be an effective, low-cost tool to identify pathogenic bacteria.

Diversity of bacteria in ships ballast water as revealed by next generation DNA sequencing.

PubMed

Brinkmeyer, Robin

2016-06-15

The bacterial diversity in ballast water from five general cargo ships calling at the Port of Houston was determined with ion semiconductor DNA sequencing (Ion Torrent PGM) of PCR amplified 16S rRNA genes. Phylogenetic analysis revealed that the composition of bacteria in ballast water did not resemble that of typical marine habitats or even open ocean waters where BWEs occur. The predominant group of bacteria in ships conducting BWEs was the Roseobacter clade within the Alphaproteobacteria. In contrast, Gammaproteobacteria were predominant in the ship that did not conduct a BWE. All the ships contained human, fish, and terrestrial plant pathogens as well as bacteria indicative of fecal or activated sludge contamination. Most of the 60 pathogens had not been detected in ballast water previously. Among these were the human pathogens Corynebacterium diptheriae and several Legionella species and the fish pathogens Francisella piscicida and Piscirickettsia salmonis. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Use of Colorimetric Sensor Arrays to Discriminate between Pathogenic Bacteria

PubMed Central

Lonsdale, Claire L.; Taba, Brian; Queralto, Nuria; Lukaszewski, Roman A.; Martino, Raymond A.; Rhodes, Paul A.; Lim, Sung H.

2013-01-01

A colorimetric sensor array is a high-dimensional chemical sensor that is cheap, compact, disposable, robust, and easy to operate, making it a good candidate technology to detect pathogenic bacteria, especially potential bioterrorism agents like Yersinia pestis and Bacillus anthracis which feature on the Center for Disease Control and Prevention’s list of potential biothreats. Here, a colorimetric sensor array was used to continuously monitor the volatile metabolites released by bacteria in solid media culture in an Advisory Committee on Dangerous Pathogen Containment Level 3 laboratory. At inoculum concentrations as low as 8 colony-forming units per plate, 4 different bacterial species were identified with 100% accuracy using logistic regression to classify the kinetic profile of sensor responses to culture headspace gas. The sensor array was able to further discriminate between different strains of the same species, including 5 strains of Yersinia pestis and Bacillus anthracis. These preliminary results suggest that disposable colorimetric sensor arrays can be an effective, low-cost tool to identify pathogenic bacteria. PMID:23671629

[Current clinical significance of anaerobic bacteremia].

PubMed

Jirsa, Roman; Marešová, Veronika; Brož, Zdeněk

2010-10-01

to estimate tje current clinical significance of anaerobic bacteremia in a group of Czech hospitals. this retrospective analysis comprised 8 444 anaerobic blood cultures in patients admitted to four Czech hospitals between 2004 and 2007. in 16 patients, blood cultures yielded significant anaerobic bacteria. Thus, anaerobic bacteremia accounted for less than 2 % of clinically significant bacteremia. Four patients (18 %) died but none of the deaths could be clearly attributable to anaerobic bacteria in the bloodstream. The most common comorbidities predisposing to anaerobic bacteremia and the most frequent sources of infection were similar to those reported by other authors. The majority of anaerobic bacteremia cases were due to gram-negative bacteria, followed by Clostridium perfringens and, surprisingly, Eubacterium spp. (particularly Eubacterium lentum). anaerobic bacteremia remains rare. The comparison of our data with those by other authors suggests that (despite the reported high mortality) the actual clinical significance of anaerobic bacteremia is rather controversial and that the anaerobic bacteremia might not correspond to more serious pathogenic role of the anaerobic bacteria as the source of infection.

The microbiome of the maxillary sinus and middle nasal meatus in chronic rhinosinusitis.

PubMed

Ivanchenko, O A; Karpishchenko, S A; Kozlov, R S; Krechikova, O I; Otvagin, I V; Sopko, O N; Piskunov, G Z; Lopatin, A S

2016-03-01

This multicenter study was focused on the identification of the microorganisms inhabiting the maxillary sinus and middle nasal meatus in chronic rhinosinusitis. 112 middle meatus swabs and 112 maxillary sinus aspirates from 103 patients were available for culture. A total of 244 strains of microorganisms representing more than 50 families were identified in the maxillary sinus and middle nasal meatus (164 and 80, respectively). These included 154 (63.0%) strains of aerobic bacteria from 32 species and 90 (37.0%) strains of anaerobic bacteria from 23 species. Aerobes were more common than anaerobes in both the nasal cavity (78.7% vs. 21.3%) and in the maxillary sinus (55.2% vs. 44.8%). Species of Streptococci (28.8%) and Prevotella (17.8%) were the most common findings in the maxillary sinus aspirates. S. pneumonia, H. influenza, and S. aureus were relatively rare, and found in only 6.7%, 5.4%, and 8.9% of the samples, respectively. The results obtained suggest that common upper airway pathogens do not play a major role in the pathogenesis of chronic rhinosinusitis. The microbiome of inflamed sinonasal mucosa is extremely diverse and involves exotic species of bacteria that, to date, have not been considered as potential inhabitants of the paranasal sinuses.

Detailed analysis of metagenome datasets obtained from biogas-producing microbial communities residing in biogas reactors does not indicate the presence of putative pathogenic microorganisms

PubMed Central

2013-01-01

Background In recent years biogas plants in Germany have been supposed to be involved in amplification and dissemination of pathogenic bacteria causing severe infections in humans and animals. In particular, biogas plants are discussed to contribute to the spreading of Escherichia coli infections in humans or chronic botulism in cattle caused by Clostridium botulinum. Metagenome datasets of microbial communities from an agricultural biogas plant as well as from anaerobic lab-scale digesters operating at different temperatures and conditions were analyzed for the presence of putative pathogenic bacteria and virulence determinants by various bioinformatic approaches. Results All datasets featured a low abundance of reads that were taxonomically assigned to the genus Escherichia or further selected genera comprising pathogenic species. Higher numbers of reads were taxonomically assigned to the genus Clostridium. However, only very few sequences were predicted to originate from pathogenic clostridial species. Moreover, mapping of metagenome reads to complete genome sequences of selected pathogenic bacteria revealed that not the pathogenic species itself, but only species that are more or less related to pathogenic ones are present in the fermentation samples analyzed. Likewise, known virulence determinants could hardly be detected. Only a marginal number of reads showed similarity to sequences described in the Microbial Virulence Database MvirDB such as those encoding protein toxins, virulence proteins or antibiotic resistance determinants. Conclusions Findings of this first study of metagenomic sequence reads of biogas producing microbial communities suggest that the risk of dissemination of pathogenic bacteria by application of digestates from biogas fermentations as fertilizers is low, because obtained results do not indicate the presence of putative pathogenic microorganisms in the samples analyzed. PMID:23557021

Infection dynamic of symbiotic bacteria in the pea aphid Acyrthosiphon pisum gut and host immune response at the early steps in the infection process.

PubMed

Renoz, François; Noël, Christine; Errachid, Abdelmounaim; Foray, Vincent; Hance, Thierry

2015-01-01

In addition to its obligatory symbiont Buchnera aphidicola, the pea aphid Acyrthosiphon pisum can harbor several facultative bacterial symbionts which can be mutualistic in the context of various ecological interactions. Belonging to a genus where many members have been described as pathogen in invertebrates, Serratia symbiotica is one of the most common facultative partners found in aphids. The recent discovery of strains able to grow outside their host allowed us to simulate environmental acquisition of symbiotic bacteria by aphids. Here, we performed an experiment to characterize the A. pisum response to the ingestion of the free-living S. symbiotica CWBI-2.3T in comparison to the ingestion of the pathogenic Serratia marcescens Db11 at the early steps in the infection process. We found that, while S. marcescens Db11 killed the aphids within a few days, S. symbiotica CWBI-2.3T did not affect host survival and colonized the whole digestive tract within a few days. Gene expression analysis of immune genes suggests that S. symbiotica CWBI-2.3T did not trigger an immune reaction, while S. marcescens Db11 did, and supports the hypothesis of a fine-tuning of the host immune response set-up for fighting pathogens while maintaining mutualistic partners. Our results also suggest that the lysosomal system and the JNK pathway are possibly involved in the regulation of invasive bacteria in aphids and that the activation of the JNK pathway is IMD-independent in the pea aphid.

Infection Dynamic of Symbiotic Bacteria in the Pea Aphid Acyrthosiphon pisum Gut and Host Immune Response at the Early Steps in the Infection Process

PubMed Central

Renoz, François; Noël, Christine; Errachid, Abdelmounaim; Foray, Vincent; Hance, Thierry

2015-01-01

In addition to its obligatory symbiont Buchnera aphidicola, the pea aphid Acyrthosiphon pisum can harbor several facultative bacterial symbionts which can be mutualistic in the context of various ecological interactions. Belonging to a genus where many members have been described as pathogen in invertebrates, Serratia symbiotica is one of the most common facultative partners found in aphids. The recent discovery of strains able to grow outside their host allowed us to simulate environmental acquisition of symbiotic bacteria by aphids. Here, we performed an experiment to characterize the A. pisum response to the ingestion of the free-living S. symbiotica CWBI-2.3T in comparison to the ingestion of the pathogenic Serratia marcescens Db11 at the early steps in the infection process. We found that, while S. marcescens Db11 killed the aphids within a few days, S. symbiotica CWBI-2.3T did not affect host survival and colonized the whole digestive tract within a few days. Gene expression analysis of immune genes suggests that S. symbiotica CWBI-2.3T did not trigger an immune reaction, while S. marcescens Db11 did, and supports the hypothesis of a fine-tuning of the host immune response set-up for fighting pathogens while maintaining mutualistic partners. Our results also suggest that the lysosomal system and the JNK pathway are possibly involved in the regulation of invasive bacteria in aphids and that the activation of the JNK pathway is IMD-independent in the pea aphid. PMID:25811863

Airborne Multidrug-Resistant Bacteria Isolated from a Concentrated Swine Feeding Operation

PubMed Central

Chapin, Amy; Rule, Ana; Gibson, Kristen; Buckley, Timothy; Schwab, Kellogg

2005-01-01

The use of nontherapeutic levels of antibiotics in swine production can select for antibiotic resistance in commensal and pathogenic bacteria in swine. As a result, retail pork products, as well as surface and groundwaters contaminated with swine waste, have been shown to be sources of human exposure to antibiotic-resistant bacteria. However, it is unclear whether the air within swine operations also serves as a source of exposure to antibiotic-resistant bacterial pathogens. To investigate this issue, we sampled the air within a concentrated swine feeding operation with an all-glass impinger. Samples were analyzed using a method for the isolation of Enterococcus. A total of 137 presumptive Enterococcus isolates were identified to species level using standard biochemical tests and analyzed for resistance to erythromycin, clindamycin, virginiamycin, tetracycline, and vancomycin using the agar dilution method. Thirty-four percent of the isolates were confirmed as Enterococcus, 32% were identified as coagulase-negative staphylococci, and 33% were identified as viridans group streptococci. Regardless of bacterial species, 98% of the isolates expressed high-level resistance to at least two antibiotics commonly used in swine production. None of the isolates were resistant to vancomycin, an antibiotic that has never been approved for use in livestock in the United States. In conclusion, high-level multidrug-resistant Enterococcus, coagulase-negative staphylococci, and viridans group streptococci were detected in the air of a concentrated swine feeding operation. These findings suggest that the inhalation of air from these facilities may serve as an exposure pathway for the transfer of multidrug-resistant bacterial pathogens from swine to humans. PMID:15687049

[Distribution of Pathogenic Bacteria and Its Influence on Expression of BCL-2 and BAX Protein after HSCT in the Patients with Hematological Malignancies].

PubMed

Su, Gui-Ping; Dai, Yan; Huang, Lai-Quan; Jiang, Yi-Zhi; Geng, Liang-Quan; Ding, Kai-Yang; Huang, Dong-Ping

2016-06-01

To investigate the distribution of pathogenic bacteria in the patients with hematologic malignancies received hematopoietic stem cell transplantation (HSCT) and its influence on the expression of BCL-2 and BAX proteins. The clinical data of 64 patients with malignant lymphoma (ML) received auto-HSCT from January 2011 to December 2015 in our hospital were analyzed. On basis of post-treansplant infection, the patients were divided into infection group (36 cases) and non-infection group (28 cases). The distribution of pathogenic bacteria in 2 groups was identified, the T lymphocyte subsets of peripheral blood, expression level of apoptotic proteins and C-reaction protein (CRP) in 2 group were detected. Thirty-six strains of pathogenic bacteria were isolated from 36 case of hematological malignancy after HSCT, including 24 strains of Gram-negative bacteria (66.67%) with predominamce of klebsiella pneumoniae (19.44%). The periperal blood CD4+ (t=2.637, P<0.01), CD4+/CD8+ ratio (t=8.223, P<0.01), BCL-2 protein (t=5.852, P<0.05), BCL-2/BAX ratio (t=14.56, P<0.01) in infection group were significantly lower than those in non-infection group, while CD8+ (t=2.285, P=<0.01), CRP (t=39.71, P<0.01), BAX level in infection group were higher than those in non-infection group. The pearson correcation analysis showed that the CD4+/CD8+ ratio in infection group positively correlated with BCL-2/BAX ratio (t=0.341, P<0.05), while serum CRP level in infection group negatively correlated with BCL-2/BAX ratio (t=-0.362, P<0.05). The pathogenic bacteria infecting ML patients after HSCT were mainly Gram-negative bacteria. The post-transplant infection can promote the expression up-regulation of related inflammatory factors and apoptotic proteins. The pathogens may be involved in cell apoptisis that provides a new strategy to treat the hematologic malignancies.

The Sweet Tooth of Bacteria: Common Themes in Bacterial Glycoconjugates

PubMed Central

Tytgat, Hanne L. P.

2014-01-01

SUMMARY Humans have been increasingly recognized as being superorganisms, living in close contact with a microbiota on all their mucosal surfaces. However, most studies on the human microbiota have focused on gaining comprehensive insights into the composition of the microbiota under different health conditions (e.g., enterotypes), while there is also a need for detailed knowledge of the different molecules that mediate interactions with the host. Glycoconjugates are an interesting class of molecules for detailed studies, as they form a strain-specific barcode on the surface of bacteria, mediating specific interactions with the host. Strikingly, most glycoconjugates are synthesized by similar biosynthesis mechanisms. Bacteria can produce their major glycoconjugates by using a sequential or an en bloc mechanism, with both mechanistic options coexisting in many species for different macromolecules. In this review, these common themes are conceptualized and illustrated for all major classes of known bacterial glycoconjugates, with a special focus on the rather recently emergent field of glycosylated proteins. We describe the biosynthesis and importance of glycoconjugates in both pathogenic and beneficial bacteria and in both Gram-positive and -negative organisms. The focus lies on microorganisms important for human physiology. In addition, the potential for a better knowledge of bacterial glycoconjugates in the emerging field of glycoengineering and other perspectives is discussed. PMID:25184559

Antimicrobial properties of Cocos nucifera (coconut) husk: An extrapolation to oral health

PubMed Central

Jose, Maji; Cyriac, Maria B; Pai, Vidya; Varghese, Ipe; Shantaram, Manjula

2014-01-01

Background and Objectives: Brushing the teeth with fibrous husk of Cocos nucifera (coconut) is a common oral hygiene practice among people of rural areas of South India. However, the probable antimicrobial properties of this plant material against common oral pathogens have not been proved scientifically. Therefore, the present study was designed. Materials and Methods: Alcoholic extract of the husk of Cocos nucifera was prepared and the antimicrobial properties against common oral pathogens like cariogenic bacteria, periodontal pathogens, and candidal organisms were performed by the Agar Well Diffusion Method. The results obtained were then subjected to statistical analysis using One-Way Analysis of Variance (ANOVA) and the Tukey's Honestly Significant Difference (HSD). Results: The alcoholic extract of Cocos nucifera showed a significant concentration-dependent antimicrobial activity, expressed as a zone of inhibition with respect to all tested organisms except Actinomyces species. The inhibitory effect was more significant, with a majority of cariogenic organisms and Candida, with a zone of inhibition ranging from 4.6 mm to 16.3 mm. However, the effect was lesser with Cocos nucifera compared to chlorhexidine. Minimum inhibitory concentration (MIC) ranged from 50 mg/ml to 75 mg/ml. Conclusion: Cocos nucifera has a significant inhibitory action against common oral pathogens, indicating the presence of highly effective antimicrobial compounds. Therefore, it is proved that its use can contribute to oral health to a great extent. Identification of these active compounds provides the scope for incorporating it into a modern oral care system, so as to control oral diseases. PMID:25097415

Oligo-DNA Custom Macroarray for Monitoring Major Pathogenic and Non-Pathogenic Fungi and Bacteria in the Phyllosphere of Apple Trees

PubMed Central

He, Ying-Hong; Isono, Sayaka; Shibuya, Makoto; Tsuji, Masaharu; Adkar Purushothama, Charith-Raj; Tanaka, Kazuaki; Sano, Teruo

2012-01-01

Background To monitor the richness in microbial inhabitants in the phyllosphere of apple trees cultivated under various cultural and environmental conditions, we developed an oligo-DNA macroarray for major pathogenic and non-pathogenic fungi and bacteria inhabiting the phyllosphere of apple trees. Methods and Findings First, we isolated culturable fungi and bacteria from apple orchards by an agar-plate culture method, and detected 32 fungal and 34 bacterial species. Alternaria, Aureobasidium, Cladosporium, Rhodotorula, Cystofilobasidium, and Epicoccum genera were predominant among the fungi, and Bacillus, Pseudomonas, Sphingomonas, Methylobacterium, and Pantoea genera were predominant among the bacteria. Based on the data, we selected 29 major non-pathogenic and 12 phytopathogenic fungi and bacteria as the targets of macroarray. Forty-one species-specific 40-base pair long oligo-DNA sequences were selected from the nucleotide sequences of rDNA-internal transcribed spacer region for fungi and 16S rDNA for bacteria. The oligo-DNAs were fixed on nylon membrane and hybridized with digoxigenin-labeled cRNA probes prepared for each species. All arrays except those for Alternaria, Bacillus, and their related species, were specifically hybridized. The array was sensitive enough to detect 103 CFU for Aureobasidium pullulans and Bacillus cereus. Nucleotide sequencing of 100 each of independent fungal rDNA-ITS and bacterial 16S-rDNA sequences from apple tree was in agreement with the macroarray data obtained using the same sample. Finally, we analyzed the richness in the microbial inhabitants in the samples collected from apple trees in four orchards. Major apple pathogens that cause scab, Alternaria blotch, and Marssonina blotch were detected along with several non-phytopathogenic fungal and bacterial inhabitants. Conclusions The macroarray technique presented here is a strong tool to monitor the major microbial species and the community structures in the phyllosphere of apple trees and identify key species antagonistic, supportive or co-operative to specific pathogens in the orchard managed under different environmental conditions. PMID:22479577

Oligo-DNA custom macroarray for monitoring major pathogenic and non-pathogenic fungi and bacteria in the phyllosphere of apple trees.

PubMed

He, Ying-Hong; Isono, Sayaka; Shibuya, Makoto; Tsuji, Masaharu; Adkar Purushothama, Charith-Raj; Tanaka, Kazuaki; Sano, Teruo

2012-01-01

To monitor the richness in microbial inhabitants in the phyllosphere of apple trees cultivated under various cultural and environmental conditions, we developed an oligo-DNA macroarray for major pathogenic and non-pathogenic fungi and bacteria inhabiting the phyllosphere of apple trees. First, we isolated culturable fungi and bacteria from apple orchards by an agar-plate culture method, and detected 32 fungal and 34 bacterial species. Alternaria, Aureobasidium, Cladosporium, Rhodotorula, Cystofilobasidium, and Epicoccum genera were predominant among the fungi, and Bacillus, Pseudomonas, Sphingomonas, Methylobacterium, and Pantoea genera were predominant among the bacteria. Based on the data, we selected 29 major non-pathogenic and 12 phytopathogenic fungi and bacteria as the targets of macroarray. Forty-one species-specific 40-base pair long oligo-DNA sequences were selected from the nucleotide sequences of rDNA-internal transcribed spacer region for fungi and 16S rDNA for bacteria. The oligo-DNAs were fixed on nylon membrane and hybridized with digoxigenin-labeled cRNA probes prepared for each species. All arrays except those for Alternaria, Bacillus, and their related species, were specifically hybridized. The array was sensitive enough to detect 10(3) CFU for Aureobasidium pullulans and Bacillus cereus. Nucleotide sequencing of 100 each of independent fungal rDNA-ITS and bacterial 16S-rDNA sequences from apple tree was in agreement with the macroarray data obtained using the same sample. Finally, we analyzed the richness in the microbial inhabitants in the samples collected from apple trees in four orchards. Major apple pathogens that cause scab, Alternaria blotch, and Marssonina blotch were detected along with several non-phytopathogenic fungal and bacterial inhabitants. The macroarray technique presented here is a strong tool to monitor the major microbial species and the community structures in the phyllosphere of apple trees and identify key species antagonistic, supportive or co-operative to specific pathogens in the orchard managed under different environmental conditions.

An enteric virus can replace the beneficial function of commensal bacteria

PubMed Central

Kernbauer, Elisabeth; Ding, Yi; Cadwell, Ken

2014-01-01

Intestinal microbial communities have profound effects on host physiology1. Whereas the symbiotic contribution of commensal bacteria is well established, the role of eukaryotic viruses that are present in the gastrointestinal tract under homeostatic conditions is undefined2,3. Here, we demonstrate that a common enteric RNA virus can replace the beneficial function of commensal bacteria in the intestine. Murine norovirus (MNV) infection of germfree or antibiotics-treated mice restored intestinal morphology and lymphocyte function without inducing overt inflammation and disease. The presence of MNV also suppressed an expansion of group 2 innate lymphoid cells (ILCs) observed in the absence of bacteria, and induced transcriptional changes in the intestine associated with immune development and type I interferon (IFN) signaling. Consistent with this observation, the IFNα receptor was essential for the ability of MNV to compensate for bacterial depletion. Importantly, MNV infection offset the deleterious effect of antibiotics-treatment in models of intestinal injury and pathogenic bacterial infection. These data indicate that eukaryotic viruses have the capacity to support intestinal homeostasis and shape mucosal immunity akin to commensal bacteria. PMID:25409145

Acoustic impedance matched buffers enable separation of bacteria from blood cells at high cell concentrations.

PubMed

Ohlsson, Pelle; Petersson, Klara; Augustsson, Per; Laurell, Thomas

2018-06-14

Sepsis is a common and often deadly systemic response to an infection, usually caused by bacteria. The gold standard for finding the causing pathogen in a blood sample is blood culture, which may take hours to days. Shortening the time to diagnosis would significantly reduce mortality. To replace the time-consuming blood culture we are developing a method to directly separate bacteria from red and white blood cells to enable faster bacteria identification. The blood cells are moved from the sample flow into a parallel stream using acoustophoresis. Due to their smaller size, the bacteria are not affected by the acoustic field and therefore remain in the blood plasma flow and can be directed to a separate outlet. When optimizing for sample throughput, 1 ml of undiluted whole blood equivalent can be processed within 12.5 min, while maintaining the bacteria recovery at 90% and the blood cell removal above 99%. That makes this the fastest label-free microfluidic continuous flow method per channel to separate bacteria from blood with high bacteria recovery (>80%). The high throughput was achieved by matching the acoustic impedance of the parallel stream to that of the blood sample, to avoid that acoustic forces relocate the fluid streams.

Nasopharyngeal bacterial burden and antibiotics: Influence on inflammatory markers and disease severity in infants with respiratory syncytial virus bronchiolitis.

PubMed

Suárez-Arrabal, M Carmen; Mella, Cesar; Lopez, Santiago M; Brown, Nicole V; Hall, Mark W; Hammond, Sue; Shiels, William; Groner, Judith; Marcon, Mario; Ramilo, Octavio; Mejias, Asuncion

2015-10-01

Animal studies suggest that RSV increases nasopharyngeal (NP) bacterial colonization facilitating bacterial infections. We investigated the influence of antibiotic treatment and colonization with potentially pathogenic bacteria on inflammatory markers and disease severity in RSV-infected in infants. Healthy young infants hospitalized with RSV bronchiolitis (n = 136) and age-matched healthy controls (n = 23) were enrolled and NP samples cultured for potentially pathogenic bacteria including: Gram-positive bacteria (GPB): Staphylococcus aureus, Streptococcus pneumoniae, β-hemolytic Streptococcus; and Gram-negative bacteria (GNB): Moraxella catarrhalis and Haemophilus influenzae. Clinical parameters and plasma IL-8, IL-6 and TNF-α concentrations were compared according to the bacterial class and antibiotic treatment. Antibiotic treatment decreased by 10-fold NP bacterial recovery. Eighty-one percent of RSV infants who did not receive antibiotics before sample collection were colonized with pathogenic bacteria. Overall, GNB were identified in 21% of patients versus 4% of controls who were mostly colonized with GPB. Additionally, in RSV patients NP white blood cell counts (p = 0.026), and blood neutrophils (p = 0.02) were higher in those colonized with potentially pathogenic bacteria versus respiratory flora. RSV patients colonized with GNB had higher plasma IL-8 (p = 0.01) and IL-6 (p < 0.01) concentrations than controls, and required longer duration of oxygen (p = 0.049). Infants with RSV bronchiolitis colonized with potentially pathogenic bacteria had increased numbers of mucosal and systemic inflammatory cells. Specifically, colonization with GNB was associated with higher concentrations of proinflammatory cytokines and a trend towards increased disease severity. Copyright © 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria.

PubMed

Troxell, Bryan; Hassan, Hosni M

2013-01-01

In the ancient anaerobic environment, ferrous iron (Fe(2+)) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe(3+)) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe(3+), bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe(3+). However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe(2+) as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria.

Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria

PubMed Central

Troxell, Bryan; Hassan, Hosni M.

2013-01-01

In the ancient anaerobic environment, ferrous iron (Fe2+) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe3+) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe3+, bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe3+. However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe2+ as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria. PMID:24106689

PATHOGENICITY OF DRINKING WATER ISOLATES OF HETEROTROPHIC BACTERIA WITH PUTATIVE VIRULENCE FACTORS

EPA Science Inventory

Although the heterotrophic plate count (HPC) bacteria normally found in potable water are not a threat to the healthy population, some of them may be opportunistic pathogens that could cause adverse health effects in individuals with impaired immune systems. Earlier studies of t...

Hyperspectral microscope imaging methods to classify gram-positive and gram-negative foodborne pathogenic bacteria

USDA-ARS?s Scientific Manuscript database

An acousto-optic tunable filter-based hyperspectral microscope imaging method has potential for identification of foodborne pathogenic bacteria from microcolony rapidly with a single cell level. We have successfully developed the method to acquire quality hyperspectral microscopic images from variou...

Classification of gram-positive and gram-negative foodborne pathogenic bacteria with hyperspectral microscope imaging

USDA-ARS?s Scientific Manuscript database

Optical method with hyperspectral microscope imaging (HMI) has potential for identification of foodborne pathogenic bacteria from microcolonies rapidly with a cell level. A HMI system that provides both spatial and spectral information could be an effective tool for analyzing spectral characteristic...

Pilot study using wheat bran to mitigate malnutrition and enteric pathogens

USDA-ARS?s Scientific Manuscript database

In 2015, 4.9 million children under the age of five died from infectious, neonatal, or nutritional conditions. Malnourished children have an increased susceptibility to enteric pathogens and diarrhea, which flush commensal bacteria from the intestines. Commensal bacteria in the intestines regulate n...

Methods for broth dilution susceptibility testing of bacteria isolated from aquatic animals; approved guideline-second edition

USDA-ARS?s Scientific Manuscript database

Antimicrobial susceptibility testing is recommended to determine which antimicrobial agents should be considered for treating a bacterial pathogen. Many bacteria that cause disease in aquatic animals require growth conditions that vary substantially from routine terrestrial pathogens. It has thus ...

Microbiome analysis reveals the abundance of bacterial pathogens in Rousettus leschenaultii guano

PubMed Central

Banskar, Sunil; Bhute, Shrikant S.; Suryavanshi, Mangesh V.; Punekar, Sachin; Shouche, Yogesh S.

2016-01-01

Bats are crucial for proper functioning of an ecosystem. They provide various important services to ecosystem and environment. While, bats are well-known carrier of pathogenic viruses, their possible role as a potential carrier of pathogenic bacteria is under-explored. Here, using culture-based approach, employing multiple bacteriological media, over thousand bacteria were cultivated and identified from Rousettus leschenaultii (a frugivorous bat species), the majority of which were from the family Enterobacteriaceae and putative pathogens. Next, pathogenic potential of most frequently cultivated component of microbiome i.e. Escherichia coli was assessed to identify its known pathotypes which revealed the presence of virulent factors in many cultivated E. coli isolates. Applying in-depth bacterial community analysis using high-throughput 16 S rRNA gene sequencing, a high inter-individual variation was observed among the studied guano samples. Interestingly, a higher diversity of bacterial communities was observed in decaying guano representative. The search against human pathogenic bacteria database at 97% identity, a small proportion of sequences were found associated to well-known human pathogens. The present study thus indicates that this bat species may carry potential bacterial pathogens and advice to study the effect of these pathogens on bats itself and the probable mode of transmission to humans and other animals. PMID:27845426

Microbiome analysis reveals the abundance of bacterial pathogens in Rousettus leschenaultii guano.

PubMed

Banskar, Sunil; Bhute, Shrikant S; Suryavanshi, Mangesh V; Punekar, Sachin; Shouche, Yogesh S

2016-11-15

Bats are crucial for proper functioning of an ecosystem. They provide various important services to ecosystem and environment. While, bats are well-known carrier of pathogenic viruses, their possible role as a potential carrier of pathogenic bacteria is under-explored. Here, using culture-based approach, employing multiple bacteriological media, over thousand bacteria were cultivated and identified from Rousettus leschenaultii (a frugivorous bat species), the majority of which were from the family Enterobacteriaceae and putative pathogens. Next, pathogenic potential of most frequently cultivated component of microbiome i.e. Escherichia coli was assessed to identify its known pathotypes which revealed the presence of virulent factors in many cultivated E. coli isolates. Applying in-depth bacterial community analysis using high-throughput 16 S rRNA gene sequencing, a high inter-individual variation was observed among the studied guano samples. Interestingly, a higher diversity of bacterial communities was observed in decaying guano representative. The search against human pathogenic bacteria database at 97% identity, a small proportion of sequences were found associated to well-known human pathogens. The present study thus indicates that this bat species may carry potential bacterial pathogens and advice to study the effect of these pathogens on bats itself and the probable mode of transmission to humans and other animals.

Whole genome sequencing revealed host adaptation-focused genomic plasticity of pathogenic Leptospira

PubMed Central

Xu, Yinghua; Zhu, Yongzhang; Wang, Yuezhu; Chang, Yung-Fu; Zhang, Ying; Jiang, Xiugao; Zhuang, Xuran; Zhu, Yongqiang; Zhang, Jinlong; Zeng, Lingbing; Yang, Minjun; Li, Shijun; Wang, Shengyue; Ye, Qiang; Xin, Xiaofang; Zhao, Guoping; Zheng, Huajun; Guo, Xiaokui; Wang, Junzhi

2016-01-01

Leptospirosis, caused by pathogenic Leptospira spp., has recently been recognized as an emerging infectious disease worldwide. Despite its severity and global importance, knowledge about the molecular pathogenesis and virulence evolution of Leptospira spp. remains limited. Here we sequenced and analyzed 102 isolates representing global sources. A high genomic variability were observed among different Leptospira species, which was attributed to massive gene gain and loss events allowing for adaptation to specific niche conditions and changing host environments. Horizontal gene transfer and gene duplication allowed the stepwise acquisition of virulence factors in pathogenic Leptospira evolved from a recent common ancestor. More importantly, the abundant expansion of specific virulence-related protein families, such as metalloproteases-associated paralogs, were exclusively identified in pathogenic species, reflecting the importance of these protein families in the pathogenesis of leptospirosis. Our observations also indicated that positive selection played a crucial role on this bacteria adaptation to hosts. These novel findings may lead to greater understanding of the global diversity and virulence evolution of Leptospira spp. PMID:26833181

Pathogens Inactivated by Low-Energy-Electron Irradiation Maintain Antigenic Properties and Induce Protective Immune Responses

PubMed Central

Fertey, Jasmin; Bayer, Lea; Grunwald, Thomas; Pohl, Alexandra; Beckmann, Jana; Gotzmann, Gaby; Casado, Javier Portillo; Schönfelder, Jessy; Rögner, Frank-Holm; Wetzel, Christiane; Thoma, Martin; Bailer, Susanne M.; Hiller, Ekkehard; Rupp, Steffen; Ulbert, Sebastian

2016-01-01

Inactivated vaccines are commonly produced by incubating pathogens with chemicals such as formaldehyde or β-propiolactone. This is a time-consuming process, the inactivation efficiency displays high variability and extensive downstream procedures are often required. Moreover, application of chemicals alters the antigenic components of the viruses or bacteria, resulting in reduced antibody specificity and therefore stimulation of a less effective immune response. An alternative method for inactivation of pathogens is ionizing radiation. It acts very fast and predominantly damages nucleic acids, conserving most of the antigenic structures. However, currently used irradiation technologies (mostly gamma-rays and high energy electrons) require large and complex shielding constructions to protect the environment from radioactivity or X-rays generated during the process. This excludes them from direct integration into biological production facilities. Here, low-energy electron irradiation (LEEI) is presented as an alternative inactivation method for pathogens in liquid solutions. LEEI can be used in normal laboratories, including good manufacturing practice (GMP)- or high biosafety level (BSL)-environments, as only minor shielding is necessary. We show that LEEI efficiently inactivates different viruses (influenza A (H3N8), porcine reproductive and respiratory syndrome virus (PRRSV), equine herpesvirus 1 (EHV-1)) and bacteria (Escherichia coli) and maintains their antigenicity. Moreover, LEEI-inactivated influenza A viruses elicit protective immune responses in animals, as analyzed by virus neutralization assays and viral load determination upon challenge. These results have implications for novel ways of developing and manufacturing inactivated vaccines with improved efficacy. PMID:27886076

Potential probiotics from Indian major carp, Cirrhinus mrigala. Characterization, pathogen inhibitory activity, partial characterization of bacteriocin and production of exoenzymes.

PubMed

Mukherjee, Anjan; Dutta, Dipanjan; Banerjee, Sudeshna; Ringø, Einar; Breines, Eva Marie; Hareide, Ellinor; Chandra, Goutam; Ghosh, Koushik

2016-10-01

The study explored antagonistic activity of the cellular components of potential probiotic bacteria from mrigal (Cirrhinus mrigala) against fish pathogens with a basic insight of the chemical nature of the antagonistic compound. Totally 208 autochthonous gut bacteria were isolated, of which 22 strains revealed antagonism towards ≥2 of the six common fish pathogens. Zones of inhibition (halo diameter) were presented as score and the four most promising strains were selected as putative probiotics based on the cumulative score assigned. Further, evaluation of different cellular components exhibited bactericidal activity against the fish pathogens. Verification of other probiotic properties revealed that each of the selected strains produced diverse extra-cellular enzymes. The selected strains grew better in intestinal mucus than skin mucus, were resistant to diluted bile juice (2-20%) and safe for the target fish. The extracellular product used as crude bacteriocin revealed thermostability (up to 90°C) and activity over wide pH range (4-9). Partial loss of activity through treatment with proteinase-K and trypsin indicated proteinaceous nature of the antibacterial compound produced by the probiotic strains. 16S rRNA partial gene sequencing revealed that the four strains CM1FG7, CM1HG5, CM3FG19 and CM3HG10 were similar to Bacillus stratosphericus (KM277362), Bacillus aerophilus (KM277363), Bacillus licheniformis (KM277364) and Solibacillus silvestris (KM277365), respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

An overview of bacterial nomenclature with special reference to plant pathogens.

PubMed

Young, J M

2008-12-01

The nomenclature of plant pathogenic bacteria is regulated by the International Code of Nomenclature of Prokaryotes and the International Standards for Naming Pathovars of Phytopathogenic Bacteria. The object of these regulations is to ensure that nomenclature is unambiguous, with correct designations in genera and species and, for many plant pathogens, in infrasubspecies as pathovars. Failure to apply these regulations or to apply them carelessly introduces confusion and misunderstanding over the intended identity of particular pathogens. In this review, bacterial nomenclature is introduced in the context of general communication, with a brief history of the origins of modern bacterial nomenclature. A critical overview of the Code pays most attention to those Rules that are relevant to naming new taxa and new combinations, with comments on common misunderstandings. There follows an account of the application of infrasubspecies, specifically of pathovars as regulated by the Standards for Naming Pathovars. Both the Code and Standards, written almost 30 years ago in response to the exigencies of the time, could be revised to improve clarity. It is not possible for either the Code or the Standards to give formal guidance to the process of translation of pathovars, governed by the Standards, to higher taxonomic ranks, governed by the Code. If the introduction of ambiguity of names is to be avoided in making such translations, then it is the responsibility of individual bacteriologists to consider carefully the nomenclatural implications and outcomes of their proposals.

Etiology of respiratory disease in non-vaccinated, non-medicated calves in rearing herds.

PubMed

Autio, T; Pohjanvirta, T; Holopainen, R; Rikula, U; Pentikäinen, J; Huovilainen, A; Rusanen, H; Soveri, T; Sihvonen, L; Pelkonen, S

2007-01-31

The aim of this study was to examine the occurrence of bacterial, mycoplasmal and viral pathogens in the lower respiratory tract of calves in all-in all-out calf-rearing units. According to clinical status, non-medicated calves with and without respiratory disease signs were selected of the 40 herds investigated to analyse the micro-organisms present in healthy and diseased calves. Tracheobronchial lavage (TBL) and paired serum samples were analysed for bacteria, mycoplasmas, respiratory syncytial virus (RSV), parainfluenza virus 3 (PIV3), bovine corona virus (BCV) and bovine adenovirus (BAV). Pasteurella multocida was the most common bacterial pathogen. It was isolated from 34% of the TBL samples in 28 herds and was associated with clinical respiratory disease (p < 0.05) when other pathogenic bacteria or mycoplasma were present in the sample. Mannheimia spp. and Histophilus somni were rarely found. Mycoplasma bovis was not detected at all. Ureaplasma diversum was associated with clinical respiratory disease (p < 0.05). TBL samples from healthy or suspect calves were more often negative in bacterial culture than samples from diseased calves (p < 0.05). No viral infections were detected in six herds, while 16-21 herds had RSV, BCV, BAV or PIV3. In the herds that had calves seroconverted to BCV, respiratory shedding of BCV was more frequently observed than faecal shedding. This study showed that the microbial combinations behind BRD were diverse between herds. M. bovis, an emerging pathogen in many countries, was not detected.

Global Expression Profile of Biofilm Resistance to Antimicrobial Compounds in the Plant-Pathogenic Bacterium Xylella fastidiosa Reveals Evidence of Persister Cells

PubMed Central

Muranaka, Lígia S.; Takita, Marco A.; Olivato, Jacqueline C.; Kishi, Luciano T.

2012-01-01

Investigations of biofilm resistance response rarely focus on plant-pathogenic bacteria. Since Xylella fastidiosa is a multihost plant-pathogenic bacterium that forms biofilm in the xylem, the behavior of its biofilm in response to antimicrobial compounds needs to be better investigated. We analyzed here the transcriptional profile of X. fastidiosa subsp. pauca in response to inhibitory and subinhibitory concentrations of copper and tetracycline. Copper-based products are routinely used to control citrus diseases in the field, while antibiotics are more widely used for bacterial control in mammals. The use of antimicrobial compounds triggers specific responses to each compound, such as biofilm formation and phage activity for copper. Common changes in expression responses comprise the repression of genes associated with metabolic functions and movement and the induction of toxin-antitoxin systems, which have been associated with the formation of persister cells. Our results also show that these cells were found in the population at a ca. 0.05% density under inhibitory conditions for both antimicrobial compounds and that pretreatment with subinhibitory concentration of copper increases this number. No previous report has detected the presence of these cells in X. fastidiosa population, suggesting that this could lead to a multidrug tolerance response in the biofilm under a stressed environment. This is a mechanism that has recently become the focus of studies on resistance of human-pathogenic bacteria to antibiotics and, based on our data, it seems to be more broadly applicable. PMID:22730126

Bacterial Pathogens Induce Abscess Formation by CD4+ T-Cell Activation via the CD28–B7-2 Costimulatory Pathway

PubMed Central

Tzianabos, Arthur O.; Chandraker, Anil; Kalka-Moll, Wiltrud; Stingele, Francesca; Dong, Victor M.; Finberg, Robert W.; Peach, Robert; Sayegh, Mohamed H.

2000-01-01

Abscesses are a classic host response to infection by many pathogenic bacteria. The immunopathogenesis of this tissue response to infection has not been fully elucidated. Previous studies have suggested that T cells are involved in the pathologic process, but the role of these cells remains unclear. To delineate the mechanism by which T cells mediate abscess formation associated with intra-abdominal sepsis, the role of T-cell activation and the contribution of antigen-presenting cells via CD28-B7 costimulation were investigated. T cells activated in vitro by zwitterionic bacterial polysaccharides (Zps) known to induce abscess formation required CD28-B7 costimulation and, when adoptively transferred to the peritoneal cavity of naïve rats, promoted abscess formation. Blockade of T-cell activation via the CD28-B7 pathway in animals with CTLA4Ig prevented abscess formation following challenge with different bacterial pathogens, including Staphylococcus aureus, Bacteroides fragilis, and a combination of Enterococcus faecium and Bacteroides distasonis. In contrast, these animals had an increased abscess rate following in vivo T-cell activation via CD28 signaling. Abscess formation in vivo and T-cell activation in vitro required costimulation by B7-2 but not B7-1. These results demonstrate that abscess formation by pathogenic bacteria is under the control of a common effector mechanism that requires T-cell activation via the CD28–B7-2 pathway. PMID:11083777

Global expression profile of biofilm resistance to antimicrobial compounds in the plant-pathogenic bacterium Xylella fastidiosa reveals evidence of persister cells.

PubMed

Muranaka, Lígia S; Takita, Marco A; Olivato, Jacqueline C; Kishi, Luciano T; de Souza, Alessandra A

2012-09-01

Investigations of biofilm resistance response rarely focus on plant-pathogenic bacteria. Since Xylella fastidiosa is a multihost plant-pathogenic bacterium that forms biofilm in the xylem, the behavior of its biofilm in response to antimicrobial compounds needs to be better investigated. We analyzed here the transcriptional profile of X. fastidiosa subsp. pauca in response to inhibitory and subinhibitory concentrations of copper and tetracycline. Copper-based products are routinely used to control citrus diseases in the field, while antibiotics are more widely used for bacterial control in mammals. The use of antimicrobial compounds triggers specific responses to each compound, such as biofilm formation and phage activity for copper. Common changes in expression responses comprise the repression of genes associated with metabolic functions and movement and the induction of toxin-antitoxin systems, which have been associated with the formation of persister cells. Our results also show that these cells were found in the population at a ca. 0.05% density under inhibitory conditions for both antimicrobial compounds and that pretreatment with subinhibitory concentration of copper increases this number. No previous report has detected the presence of these cells in X. fastidiosa population, suggesting that this could lead to a multidrug tolerance response in the biofilm under a stressed environment. This is a mechanism that has recently become the focus of studies on resistance of human-pathogenic bacteria to antibiotics and, based on our data, it seems to be more broadly applicable.

A new laboratory cultivation of Paramecium bursaria using non-pathogenic bacteria strains.

PubMed

Bator, Tomasz

2010-01-01

In most studies dealing with the laboratory cultivation of paramecia (Paramecium bursaria), Klebsiella pneumoniae bacteria are used to inoculate the medium. However, Klebsiella pneumoniae is a typical pathogen, and its use is always associated with a risk of infection. The aim of the present research was to examine non-pathogenic bacteria strains as components of the medium for Paramecium bursaria. The paramecia were incubated on lettuce infusions bacterized with different bacteria strains: Bacillus subtilis DSM 10, Bacillus megaterium DSM 32, Escherichia coli DSM 498, Micrococcus luteus DSM 348. A strain derived from the natural habitat of Paramecium bursaria was used as the control one. Experiments were conducted under constant light and in the dark. Paramecia cells were counted under a stereomicroscope on consecutive days of incubation. The obtained results show that the most intensive growth of Paramecium bursaria occurs in the presence of Escherichia coli DSM 498. The use of this strain as a component of the medium allows one to obtain a high number of ciliates regardless of the light conditions. It can be concluded that the Paramecium bursaria cultivation procedure can be modified by using the non-pathogenic bacteria strain Escherichia coli DSM 498 instead of Klebsiella pneumoniae.

Incidence of Bacteriocins Produced by Food-Related Lactic Acid Bacteria Active towards Oral Pathogens

PubMed Central

Zoumpopoulou, Georgia; Pepelassi, Eudoxie; Papaioannou, William; Georgalaki, Marina; Maragkoudakis, Petros A.; Tarantilis, Petros A.; Polissiou, Moschos; Tsakalidou, Effie; Papadimitriou, Konstantinos

2013-01-01

In the present study we investigated the incidence of bacteriocins produced by 236 lactic acid bacteria (LAB) food isolates against pathogenic or opportunistic pathogenic oral bacteria. This set of LAB contained several strains (≥17%) producing bacteriocins active against food-related bacteria. Interestingly only Streptococcus macedonicus ACA-DC 198 was able to inhibit the growth of Streptococcus oralis, Streptococcus sanguinis and Streptococcus gordonii, while Lactobacillus fermentum ACA-DC 179 and Lactobacillus plantarun ACA-DC 269 produced bacteriocins solely against Streptococcus oralis. Thus, the percentage of strains that were found to produce bacteriocins against oral bacteria was ~1.3%. The rarity of bacteriocins active against oral LAB pathogens produced by food-related LAB was unexpected given their close phylogenetic relationship. Nevertheless, when tested in inhibition assays, the potency of the bacteriocin(s) of S. macedonicus ACA-DC 198 against the three oral streptococci was high. Fourier-transform infrared spectroscopy combined with principal component analysis revealed that exposure of the target cells to the antimicrobial compounds caused major alterations of key cellular constituents. Our findings indicate that bacteriocins produced by food-related LAB against oral LAB may be rare, but deserve further investigation since, when discovered, they can be effective antimicrobials. PMID:23443163

Reinforcing effects of non-pathogenic bacteria and predation risk: from physiology to life history.

PubMed

Janssens, Lizanne; Stoks, Robby

2014-10-01

The important ecological role of predation risk in shaping populations, communities and ecosystems is becoming increasingly clear. In this context, synergistic effects between predation risk and other natural stressors on prey organisms are gaining attention. Although non-pathogenic bacteria can be widespread in aquatic ecosystems, their role in mediating effects of predation risk has been ignored. We here address the hypothesis that non-pathogenic bacteria may reinforce the negative effects of predation risk in larvae of the damselfly Coenagrion puella. We found synergistic effects for all three life history variables studied: mortality increased, growth reductions were magnified and bacterial load was higher when both non-lethal stressors were combined. The combined exposure to the bacterium and predation risk considerably impaired the two key antipredator mechanisms of the damselfly larvae: they no longer reduced their food intake under predation risk and showed a synergistic reduction in escape swimming speed. The reinforcing negative effects on the fitness-related traits could be explained by the observed synergistic effects on food intake, swimming muscle mass, immune function and oxidative damage. These are likely widespread consequences of energetic constraints and increased metabolic rates associated with the fight-or-flight response. We therefore hypothesize that the here documented synergistic interactions with non-pathogenic bacteria may be widespread. Our results highlight the ignored ecological role of non-pathogenic bacteria in reinforcing the negative effects of predation risk on prey organisms.

Consequences of organ choice in describing bacterial pathogen assemblages in a rodent population.

PubMed

Villette, P; Afonso, E; Couval, G; Levret, A; Galan, M; Tatard, C; Cosson, J F; Giraudoux, P

2017-10-01

High-throughput sequencing technologies now allow for rapid cost-effective surveys of multiple pathogens in many host species including rodents, but it is currently unclear if the organ chosen for screening influences the number and identity of bacteria detected. We used 16S rRNA amplicon sequencing to identify bacterial pathogens in the heart, liver, lungs, kidneys and spleen of 13 water voles (Arvicola terrestris) collected in Franche-Comté, France. We asked if bacterial pathogen assemblages within organs are similar and if all five organs are necessary to detect all of the bacteria present in an individual animal. We identified 24 bacteria representing 17 genera; average bacterial richness for each organ ranged from 1·5 ± 0·4 (mean ± standard error) to 2·5 ± 0·4 bacteria/organ and did not differ significantly between organs. The average bacterial richness when organ assemblages were pooled within animals was 4·7 ± 0·6 bacteria/animal; Operational Taxonomic Unit accumulation analysis indicates that all five organs are required to obtain this. Organ type influences bacterial assemblage composition in a systematic way (PERMANOVA, 999 permutations, pseudo-F 4,51 = 1·37, P = 0·001). Our results demonstrate that the number of organs sampled influences the ability to detect bacterial pathogens, which can inform sampling decisions in public health and wildlife ecology.

Etiologic spectrum and occurrence of coinfections in children hospitalized with community-acquired pneumonia.

PubMed

Jiang, Wujun; Wu, Min; Zhou, Jing; Wang, Yuqing; Hao, Chuangli; Ji, Wei; Zhang, Xinxing; Gu, Wenjing; Shao, Xuejun

2017-12-20

Co-infections are common in childhood community acquired pneumonia (CAP). However, their etiological pattern and clinical impact remains inconclusive. Eight hundred forty-six consecutive children with CAP were evaluated prospectively for the presence of viral and bacterial pathogens. Nasopharyngeal aspirates were examined by direct immunofluorescence assay or polymerase chain reaction (PCR) for viruses. PCR of nasopharyngeal aspirates and enzyme-linked immunosorbent assays were performed to detect M. pneumoniae. Bacteria was detected in blood, bronchoalveolar lavage specimen, or pleural fluid by culture. Causative pathogen was identified in 70.1% (593 of 846) of the patients. The most commonly detected pathogens were respiratory syncytial virus (RSV) (22.9%), human rhinovirus (HRV) (22.1%), M. pneumoniae (15.8%). Coinfection was identified in 34.6% (293 of 846) of the patients. The majority of these (209 [71.3%] of 293) were mixed viral-bacterial infections. Age < 6 months (odds ratio: 2.1; 95% confidence interval: 1.2-3.3) and admission of PICU (odds ratio: 12.5; 95% confidence interval: 1.6-97.4) were associated with mix infection. Patients with mix infection had a higher rate of PICU admission. The high mix infection burden in childhood CAP underscores a need for the enhancement of sensitive, inexpensive, and rapid diagnostics to accurately identify pneumonia pathogens.

Bighorn sheep (Ovis canadensis) sinus tumors are associated with coinfections by potentially pathogenic bacteria in the upper respiratory tract.

PubMed

Fox, Karen A; Rouse, Natalie M; Huyvaert, Kathryn P; Griffin, Karen A; Killion, Halcyon J; Jennings-Gaines, Jessica; Edwards, William H; Quackenbush, Sandra L; Miller, Michael W

2015-01-01

Bighorn sheep (Ovis canadensis) sinus tumors are hyperplastic to neoplastic, predominantly stromal masses of the paranasal sinuses that expand the sinus lining and obstruct the sinus cavities. Obstruction of the sinus cavities and disruption of normal sinus lining anatomy may interfere with clearance of bacterial pathogens from the upper respiratory tract. To examine this possibility, we explored whether the presence of sinus tumor features (tumor score) affected the likelihood of detecting potentially pathogenic bacteria from upper respiratory sinus lining tissues in bighorn sheep. We developed or used existing PCR assays for the detection of leukotoxigenic Pasteurellaceae and Mycoplasma ovipneumoniae in sinus lining tissues collected from 97 bighorn sheep in Colorado, US from 2009 to 2012. With the use of logistic regression analyses we found that tumor score was a good predictor of the probability of detecting potentially pathogenic bacteria in sinus lining tissues; we were more likely to detect potentially pathogenic bacteria from samples with high tumor scores. These findings add to our understanding of possible mechanisms for the maintenance and shedding of bacterial agents from the upper respiratory tracts of bighorn sheep.

Assessing the Pathogenicity of Halophilic Vibrio Bacteria and Other Mircroorganisms for Mammals Held in Captivity.

DTIC Science & Technology

1988-02-22

results. First, that the predominant vibrio in Hawaiian waters is V. alginolyticus whereas the predominant vibrio in the gulf of Mexico is V...Classification) [l Assessing the Pathogenecity of Halophilic Vibrio Bacteria and Other Niicroorganisms for M1arine M0ammals Held in Captivity 12...GROUP Bacteria, Vibrio , iviarine iviammals, Disease, Pathogens 1 19. ABSTRACT (Continue on reverse if necessary and identify by block number) 5 .The

Back To Bacteria.

ERIC Educational Resources Information Center

Flannery, Maura C.

1997-01-01

Explores new research about bacteria. Discusses bacterial genomes, archaea, unusual environments, evolution, pathogens, bacterial movement, biofilms, bacteria in the body, and a bacterial obsession. Contains 29 references. (JRH)

Investigation of magnetic microdiscs for bacterial pathogen detection

NASA Astrophysics Data System (ADS)

Castillo-Torres, Keisha Y.; Garraud, Nicolas; Arnold, David P.; McLamore, Eric S.

2016-05-01

Despite strict regulations to control the presence of human pathogens in our food supply, recent foodborne outbreaks have heightened public concern about food safety and created urgency to improve methods for pathogen detection. Herein we explore a potentially portable, low-cost system that uses magnetic microdiscs for the detection of bacterial pathogens in liquid samples. The system operates by optically measuring the rotational dynamics of suspended magnetic microdiscs functionalized with pathogen-binding aptamers. The soft ferromagnetic (Ni80Fe20) microdiscs exhibit a closed magnetic spin arrangement (i.e. spin vortex) with zero magnetic stray field, leading to no disc agglomeration when in free suspension. With very high surface area for functionalization and volumes 10,000x larger than commonly used superparamagnetic nanoparticles, these 1.5-μm-diameter microdiscs are well suited for tagging, trapping, actuating, or interrogating bacterial targets. This work reports a wafer-level microfabrication process for fabrication of 600 million magnetic microdiscs per substrate and measurement of their rotational dynamics response. Additionally, the biofunctionalization of the microdiscs with DNA aptamers, subsequent binding to E. coli bacteria, and their magnetic manipulation is reported.

Microbiology of Fresh Produce: Route of Contamination, Detection Methods, and Remedy.

PubMed

Rajwar, Asmita; Srivastava, Pragati; Sahgal, Manvika

2016-10-25

Fresh fruits and vegetables are an important part of a healthful diet. They provide vitamins, minerals and fiber to help keep our body healthy. Occasionally, fresh fruits and vegetables can become contaminated with harmful bacteria or viruses, which are also known as pathogens. The major family of pathogen associated with food are members of Enterobacteriaceae which commonly form a part of microbiological criteria and their presence is traditionally related to hygiene and safety of foods. Organic fertilizers, irrigation water quality and soil are major source of contamination. For removal of pathogens, various decontamination procedures are also followed to reduce microbial load on the fruits. These are chemical preservatives and irradiation. Microbiological study of fresh produce can be done by various phenotypic, biochemical and molecular techniques so that pathogen can properly be identified. The World Health Organization (WHO) developed global risk communication message and training materials to assist countries in strengthening their food educating programs. There is a need for improved surveillance systems on food-borne pathogens, on food products and on outbreaks so that comparable data are available from a wider range of countries.

Detection of Intracellular Bacterial Communities in Human Urinary Tract Infection

PubMed Central

Rosen, David A; Hooton, Thomas M; Stamm, Walter E; Humphrey, Peter A; Hultgren, Scott J

2007-01-01

Background Urinary tract infections (UTIs) are one of the most common bacterial infections and are predominantly caused by uropathogenic Escherichia coli (UPEC). While UTIs are typically considered extracellular infections, it has been recently demonstrated that UPEC bind to, invade, and replicate within the murine bladder urothelium to form intracellular bacterial communities (IBCs). These IBCs dissociate and bacteria flux out of bladder facet cells, some with filamentous morphology, and ultimately establish quiescent intracellular reservoirs that can seed recurrent infection. This IBC pathogenic cycle has not yet been investigated in humans. In this study we sought to determine whether evidence of an IBC pathway could be found in urine specimens from women with acute UTI. Methods and Findings We collected midstream, clean-catch urine specimens from 80 young healthy women with acute uncomplicated cystitis and 20 asymptomatic women with a history of UTI. Investigators were blinded to culture results and clinical history. Samples were analyzed by light microscopy, immunofluorescence, and electron microscopy for evidence of exfoliated IBCs and filamentous bacteria. Evidence of IBCs was found in 14 of 80 (18%) urines from women with UTI. Filamentous bacteria were found in 33 of 80 (41%) urines from women with UTI. None of the 20 urines from the asymptomatic comparative group showed evidence of IBCs or filaments. Filamentous bacteria were present in all 14 of the urines with IBCs compared to 19 (29%) of 66 samples with no evidence of IBCs (p < 0.001). Of 65 urines from patients with E. coli infections, 14 (22%) had evidence of IBCs and 29 (45%) had filamentous bacteria, while none of the gram-positive infections had IBCs or filamentous bacteria. Conclusions The presence of exfoliated IBCs and filamentous bacteria in the urines of women with acute cystitis suggests that the IBC pathogenic pathway characterized in the murine model may occur in humans. The findings support the occurrence of an intracellular bacterial niche in some women with cystitis that may have important implications for UTI recurrence and treatment. PMID:18092884

UniDrug-target: a computational tool to identify unique drug targets in pathogenic bacteria.

PubMed

Chanumolu, Sree Krishna; Rout, Chittaranjan; Chauhan, Rajinder S

2012-01-01

Targeting conserved proteins of bacteria through antibacterial medications has resulted in both the development of resistant strains and changes to human health by destroying beneficial microbes which eventually become breeding grounds for the evolution of resistances. Despite the availability of more than 800 genomes sequences, 430 pathways, 4743 enzymes, 9257 metabolic reactions and protein (three-dimensional) 3D structures in bacteria, no pathogen-specific computational drug target identification tool has been developed. A web server, UniDrug-Target, which combines bacterial biological information and computational methods to stringently identify pathogen-specific proteins as drug targets, has been designed. Besides predicting pathogen-specific proteins essentiality, chokepoint property, etc., three new algorithms were developed and implemented by using protein sequences, domains, structures, and metabolic reactions for construction of partial metabolic networks (PMNs), determination of conservation in critical residues, and variation analysis of residues forming similar cavities in proteins sequences. First, PMNs are constructed to determine the extent of disturbances in metabolite production by targeting a protein as drug target. Conservation of pathogen-specific protein's critical residues involved in cavity formation and biological function determined at domain-level with low-matching sequences. Last, variation analysis of residues forming similar cavities in proteins sequences from pathogenic versus non-pathogenic bacteria and humans is performed. The server is capable of predicting drug targets for any sequenced pathogenic bacteria having fasta sequences and annotated information. The utility of UniDrug-Target server was demonstrated for Mycobacterium tuberculosis (H37Rv). The UniDrug-Target identified 265 mycobacteria pathogen-specific proteins, including 17 essential proteins which can be potential drug targets. UniDrug-Target is expected to accelerate pathogen-specific drug targets identification which will increase their success and durability as drugs developed against them have less chance to develop resistances and adverse impact on environment. The server is freely available at http://117.211.115.67/UDT/main.html. The standalone application (source codes) is available at http://www.bioinformatics.org/ftp/pub/bioinfojuit/UDT.rar.

Serum inflammatory biomarkers and clinical outcomes of COPD exacerbation caused by different pathogens.

PubMed

Kawamatawong, Theerasuk; Apiwattanaporn, Apitch; Siricharoonwong, Warisara

2017-01-01

COPD exacerbation is characterized by worsening of symptoms, warranting change in treatment. Systemic and airway inflammation play roles in the pathogenesis of COPD exacerbation. We hypothesized whether increased serum inflammatory biomarkers are associated with the clinical outcomes of COPD exacerbation caused by different infectious pathogens. COPD patients with exacerbation were recruited from a hospital emergency department during 2014-2015. Serum procalcitonin (PCT) and C-reactive protein (CRP) were measured. Dyspnea, eosinopenia, consolidation, acidemia, and atrial fibrillation (DECAF) score was calculated for predicting mortality. Multiplex polymerase chain reaction was carried out for respiratory viral assay from nasopharyngeal swabs, and sputum bacterial culture was also performed. Hospital mortality, invasive mechanical ventilation requirement, and length of hospital stay (LOS) were evaluated, and their associations with clinical characteristics, DECAF score, and serum biomarkers were examined. A total of 62 COPD patients were enrolled. These patients were classified as Global Initiative for Obstructive Lung Disease (GOLD) stage 2, 3, and 4 in 12.9%, 6.4%, and 80.7% of cases, respectively. Isolated bacterial exacerbation was recovered in 30.6% of exacerbation episodes: Klebsiella pneumoniae was the most commonly identified bacteria. Viral pathogens and coinfections were noted in 9.6% and 16.1% of exacerbated patients, respectively. Influenza was the most commonly detected viral pathogen. Serum biomarkers and DECAF score for viruses, bacteria, coinfection, and noninfectious causes of exacerbations were similar. Neither DECAF score nor serum biomarkers were able to differentiate patients with and without mortality or requiring mechanical ventilation. Increased serum PCT was noted in patients with LOS ≥7 days when compared with those with LOS <7 days (0.38 ng/mL vs 0.1 ng/mL; P =0.035). Increased serum PCT is associated with longer LOS in COPD exacerbation. However, CRP and DECAF score play limited roles in predicting clinical outcome and lack an association with causes of exacerbation.

Use of Extract of Citrus sinensis as an antimicrobial agent for foodborne zoonotic pathogens and spoilage bacteria

USDA-ARS?s Scientific Manuscript database

Foodborne pathogens remain global health problems despite concerted efforts to control the transmission of these microorganisms through food. The resurgence of drug resistant bacteria has renewed interest in developing and testing new sources of antimicrobial agents to control foodborne illness. Thi...

Hydrological modeling of fecal indicator bacteria in a tropical mountain catchment

USDA-ARS?s Scientific Manuscript database

The occurrence of pathogen bacteria in surface waters is a threat to public health worldwide. In particular, inadequate sanitation resulting in high contamination of surface water with pathogens of fecal origin is a serious issue in developing countries such as Lao P.D.R. Despite the health implicat...

EFFICIENT RECOVERY OF ENTEROCOCCI FROM MARINE AND FRESH WATER BEACHES BY A 30,000 MOLECULAR WEIGHT CUTOFF HOLLOW FIBER ULTRAFILTER

EPA Science Inventory

Ultrafiltration systems have been used to concentrate pathogens from various types of fresh water samples. However, less work has been done with marine waters for the concentration of pathogens or indicator bacteria. An ultrafiltration approach to concentrate indicator bacteria...

Effect of simulated sanitizer carryover on recovery of salmonella from broiler carcass rinsates

USDA-ARS?s Scientific Manuscript database

Numerous antimicrobial chemicals are currently utilized as processing aids with the aim of reducing pathogenic bacteria on processed poultry carcasses. Carry-over of active sanitizer to a carcass rinse solution intended for detection of viable pathogenic bacteria by regulatory agencies may cause fal...

Human Health Risk Implications of Multiple Sources of Faecal Indicator Bacteria in a Recreational Waterbody

EPA Science Inventory

We evaluate the influence of multiple sources of faecal indicator bacteria in recreational water bodies on potential human health risk by considering waters impacted by human and animal sources, human and non-pathogenic sources, and animal and non-pathogenic sources. We illustrat...

Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria

PubMed Central

Castro, S.B.R.; Leal, C.A.G.; Freire, F.R.; Carvalho, D.A.; Oliveira, D.F.; Figueiredo, H.C.P.

2008-01-01

The aim of this work was to evaluate the antibacterial activity of Brazilian plants extracts against fish pathogenic bacteria. Forty six methanolic extracts were screened to identify their antibacterial properties against Streptococcus agalactiae, Flavobacterium columnare and Aeromonas hydrophila. Thirty one extracts showed antibacterial activity. PMID:24031303

The effect of bacterial environmental and metabolic stresses on a laser-induced breakdown spectroscopy (LIBS) based identification of Escherichia coli and Streptococcus viridans.

PubMed

Mohaidat, Qassem; Palchaudhuri, Sunil; Rehse, Steven J

2011-04-01

In this paper we investigate the effect that adverse environmental and metabolic stresses have on the laser-induced breakdown spectroscopy (LIBS) identification of bacterial specimens. Single-pulse LIBS spectra were acquired from a non-pathogenic strain of Escherichia coli cultured in two different nutrient media: a trypticase soy agar and a MacConkey agar with a 0.01% concentration of deoxycholate. A chemometric discriminant function analysis showed that the LIBS spectra acquired from bacteria grown in these two media were indistinguishable and easily discriminated from spectra acquired from two other non-pathogenic E. coli strains. LIBS spectra were obtained from specimens of a nonpathogenic E. coli strain and an avirulent derivative of the pathogen Streptococcus viridans in three different metabolic situations: live bacteria reproducing in the log-phase, bacteria inactivated on an abiotic surface by exposure to bactericidal ultraviolet irradiation, and bacteria killed via autoclaving. All bacteria were correctly identified regardless of their metabolic state. This successful identification suggests the possibility of testing specimens that have been rendered safe for handling prior to LIBS identification. This would greatly enhance personnel safety and lower the cost of a LIBS-based diagnostic test. LIBS spectra were obtained from pathogenic and non-pathogenic bacteria that were deprived of nutrition for a period of time ranging from one day to nine days by deposition on an abiotic surface at room temperature. All specimens were successfully classified by species regardless of the duration of nutrient deprivation. © 2011 Society for Applied Spectroscopy

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

PubMed

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

2018-04-17

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

Divergent pro-inflammatory profile of human dendritic cells in response to commensal and pathogenic bacteria associated with the airway microbiota.

PubMed

Larsen, Jeppe Madura; Steen-Jensen, Daniel Bisgaard; Laursen, Janne Marie; Søndergaard, Jonas Nørskov; Musavian, Hanieh Sadat; Butt, Tariq Mahmood; Brix, Susanne

2012-01-01

Recent studies using culture-independent methods have characterized the human airway microbiota and report microbial communities distinct from other body sites. Changes in these airway bacterial communities appear to be associated with inflammatory lung disease, yet the pro-inflammatory properties of individual bacterial species are unknown. In this study, we compared the immune stimulatory capacity on human monocyte-derived dendritic cells (DCs) of selected airway commensal and pathogenic bacteria predominantly associated with lungs of asthma or COPD patients (pathogenic Haemophillus spp. and Moraxella spp.), healthy lungs (commensal Prevotella spp.) or both (commensal Veillonella spp. and Actinomyces spp.). All bacteria were found to induce activation of DCs as demonstrated by similar induction of CD83, CD40 and CD86 surface expression. However, asthma and COPD-associated pathogenic bacteria provoked a 3-5 fold higher production of IL-23, IL-12p70 and IL-10 cytokines compared to the commensal bacteria. Based on the differential cytokine production profiles, the studied airway bacteria could be segregated into three groups (Haemophilus spp. and Moraxella spp. vs. Prevotella spp. and Veillonella spp. vs. Actinomyces spp.) reflecting their pro-inflammatory effects on DCs. Co-culture experiments found that Prevotella spp. were able to reduce Haemophillus influenzae-induced IL-12p70 in DCs, whereas no effect was observed on IL-23 and IL-10 production. This study demonstrates intrinsic differences in DC stimulating properties of bacteria associated with the airway microbiota.

Divergent Pro-Inflammatory Profile of Human Dendritic Cells in Response to Commensal and Pathogenic Bacteria Associated with the Airway Microbiota

PubMed Central

Larsen, Jeppe Madura; Steen-Jensen, Daniel Bisgaard; Laursen, Janne Marie; Søndergaard, Jonas Nørskov; Musavian, Hanieh Sadat; Butt, Tariq Mahmood; Brix, Susanne

2012-01-01

Recent studies using culture-independent methods have characterized the human airway microbiota and report microbial communities distinct from other body sites. Changes in these airway bacterial communities appear to be associated with inflammatory lung disease, yet the pro-inflammatory properties of individual bacterial species are unknown. In this study, we compared the immune stimulatory capacity on human monocyte-derived dendritic cells (DCs) of selected airway commensal and pathogenic bacteria predominantly associated with lungs of asthma or COPD patients (pathogenic Haemophillus spp. and Moraxella spp.), healthy lungs (commensal Prevotella spp.) or both (commensal Veillonella spp. and Actinomyces spp.). All bacteria were found to induce activation of DCs as demonstrated by similar induction of CD83, CD40 and CD86 surface expression. However, asthma and COPD-associated pathogenic bacteria provoked a 3–5 fold higher production of IL-23, IL-12p70 and IL-10 cytokines compared to the commensal bacteria. Based on the differential cytokine production profiles, the studied airway bacteria could be segregated into three groups (Haemophilus spp. and Moraxella spp. vs. Prevotella spp. and Veillonella spp. vs. Actinomyces spp.) reflecting their pro-inflammatory effects on DCs. Co-culture experiments found that Prevotella spp. were able to reduce Haemophillus influenzae-induced IL-12p70 in DCs, whereas no effect was observed on IL-23 and IL-10 production. This study demonstrates intrinsic differences in DC stimulating properties of bacteria associated with the airway microbiota. PMID:22363778

Rapid fluorescence detection of pathogenic bacteria using magnetic enrichment technique combined with magnetophoretic chromatography.

PubMed

Che, Yulan; Xu, Yi; Wang, Renjie; Chen, Li

2017-08-01

A rapid and sensitive analytical method was developed to detect pathogenic bacteria which combined magnetic enrichment, fluorescence labeling with polyethylene glycol (PEG) magnetophoretic chromatography. As pathogenic bacteria usually exist in complex matrixes at low concentration, an efficient enrichment is essential for diagnosis. In order to capture series types of pathogenic bacteria in samples, amino-modified magnetic nanoparticles (Fe 3 O 4 @SiO 2 -NH 2 ) were prepared for efficient enrichment by the electrostatic interaction with pathogenic bacteria. It was shown that the capture efficiency reached up to 95.4% for Escherichia coli (E. coli). Furthermore, quantitative analysis of the bacteria was achieved by using acridine orange (AO) as a fluorescence probe for the captured E. coli due to its ability of staining series types of bacteria and rapid labeling. In order to remove the free magnetic nanoparticles and redundant fluorescent reagent, the labeled suspension was poured into a PEG separation column and was separated by applying an external magnetic field. The presence of 100 cfu mL -1 E. coli could be detected for semi-quantitative analysis by observing the separation column with the naked eye, and the concentration could be further evaluated by fluorescence detection. All the above processes were finished within 80 min. It was demonstrated that a good linear relationship existed between the fluorescence intensity and the concentration of E. coli ranging from 10 2 to 10 6  cfu mL -1 , with a detection limit of 100 cfu mL -1 when E. coli acted as target bacteria. The recovery rate of E. coli was 93.6∼102.0% in tap water and cooked meat samples, and the RSD was lower than 7% (n = 6); the result coincided with the conventional plate count method. Graphical abstract ᅟ.

Role of anaerobic bacteria in biological soil disinfestation for elimination of soil-borne plant pathogens in agriculture.

PubMed

Ueki, Atsuko; Kaku, Nobuo; Ueki, Katsuji

2018-06-01

Biological soil disinfestation (BSD) or reductive soil disinfestation (RSD) is an environmental biotechnology to eliminate soil-borne plant pathogens based on functions of indigenous microbes. BSD treatments using different types of organic materials have been reported to effectively control a wide range of plant pathogens. Various studies have shown that development of reducing or anoxic conditions in soil is the most important aspect for effective BSD treatments. Substances such as organic acids, FeS, or phenolic compounds generated in the treated soil have been suggested to contribute to inactivation of pathogens. Additionally, anaerobic bacteria grown in the BSD-treated soil may produce and release enzymes with anti-pathogenic activities in soil. Clone library analyses as well as a next-generation sequence analysis based on 16S rRNA genes have revealed prosperity of obligate anaerobic bacteria from the class Clostridia in differently treated BSD soils. Two anaerobic bacterial strains isolated from BSD-treated soil samples and identified as Clostridium beijerinckii were found to decompose major cell wall polysaccharides of ascomycetous fungi, chitosan and β-1,3-glucan. C. beijerinckii is a species most frequently detected in the clone library analyses for various BSD-treated soils as a closely related species. The two anaerobic isolates severely degraded mycelial cells of the Fusarium pathogen of spinach wilt disease during anaerobic co-incubation of each isolate and the Fusarium pathogen. These reports suggest that antifungal enzymes produced by predominant anaerobic bacteria grown in the BSD-treated soil play important roles to control soil-borne fungal pathogens. Further studies using different bacterial isolates from BSD-treated soils are expected to know their anti-pathogenic abilities.

Bioaccumulation of pathogenic bacteria and amoeba by zebra mussels and their presence in watercourses.

PubMed

Mosteo, R; Goñi, P; Miguel, N; Abadías, J; Valero, P; Ormad, M P

2016-01-01

Dreissena polymorpha (the zebra mussel) has been invading freshwater bodies in Europe since the beginning of the nineteenth century. Filter-feeding organisms can accumulate and concentrate both chemical and biological contaminants in their tissues. Therefore, zebra mussels are recognized as indicators of freshwater quality. In this work, the capacity of the zebra mussel to accumulate human pathogenic bacteria and protozoa has been evaluated and the sanitary risk associated with their presence in surface water has also been assessed. The results show a good correlation between the pathogenic bacteria concentration in zebra mussels and in watercourses. Zebra mussels could therefore be used as an indicator of biological contamination. The bacteria (Escherichia coli, Enterococcus spp., Pseudomonas spp., and Salmonella spp.) and parasites (Cryptosporidium oocysts and free-living amoebae) detected in these mussels reflect a potential sanitary risk in water.

Sputum colour and bacteria in chronic bronchitis exacerbations: a pooled analysis.

PubMed

Miravitlles, Marc; Kruesmann, Frank; Haverstock, Daniel; Perroncel, Renee; Choudhri, Shurjeel H; Arvis, Pierre

2012-06-01

We examined the correlation between sputum colour and the presence of potentially pathogenic bacteria in acute exacerbations of chronic bronchitis (AECBs). Data were pooled from six multicentre studies comparing moxifloxacin with other antimicrobials in patients with an AECB. Sputum was collected before antimicrobial therapy, and bacteria were identified by culture and Gram staining. Association between sputum colour and bacteria was determined using logistic regression. Of 4,089 sputum samples, a colour was reported in 4,003; 1,898 (46.4%) were culture-positive. Green or yellow sputum samples were most likely to yield bacteria (58.9% and 45.5% of samples, respectively), compared with 18% of clear and 39% of rust-coloured samples positive for potentially pathogenic microorganisms. Factors predicting a positive culture were sputum colour (the strongest predictor), sputum purulence, increased dyspnoea, male sex and absence of fever. Green or yellow versus white sputum colour was associated with a sensitivity of 94.7% and a specificity of 15% for the presence of bacteria. Sputum colour, particularly green and yellow, was a stronger predictor of potentially pathogenic bacteria than sputum purulence and increased dyspnoea in AECB patients. However, it does not necessarily predict the need for antibiotic treatment in all patients with AECB.

Antibiofilm Activity of the Brown Alga Halidrys siliquosa against Clinically Relevant Human Pathogens

PubMed Central

Busetti, Alessandro; Thompson, Thomas P.; Tegazzini, Diana; Megaw, Julianne; Maggs, Christine A.; Gilmore, Brendan F.

2015-01-01

The marine brown alga Halidrys siliquosa is known to produce compounds with antifouling activity against several marine bacteria. The aim of this study was to evaluate the antimicrobial and antibiofilm activity of organic extracts obtained from the marine brown alga H. siliquosa against a focused panel of clinically relevant human pathogens commonly associated with biofilm-related infections. The partially fractionated methanolic extract obtained from H. siliquosa collected along the shores of Co. Donegal; Ireland; displayed antimicrobial activity against bacteria of the genus Staphylococcus; Streptococcus; Enterococcus; Pseudomonas; Stenotrophomonas; and Chromobacterium with MIC and MBC values ranging from 0.0391 to 5 mg/mL. Biofilms of S. aureus MRSA were found to be susceptible to the algal methanolic extract with MBEC values ranging from 1.25 mg/mL to 5 mg/mL respectively. Confocal laser scanning microscopy using LIVE/DEAD staining confirmed the antimicrobial nature of the antibiofilm activity observed using the MBEC assay. A bioassay-guided fractionation method was developed yielding 10 active fractions from which to perform purification and structural elucidation of clinically-relevant antibiofilm compounds. PMID:26058011

Overexpression of SOS genes in ciprofloxacin resistant Escherichia coli mutants.

PubMed

Pourahmad Jaktaji, Razieh; Pasand, Shirin

2016-01-15

Fluoroquinolones are important antibiotics for the treatment of urinary tract infections caused by Escherichia coli. Mutational studies have shown that ciprofloxacin, a member of fluoroquinolones induces SOS response and mutagenesis in pathogenic bacteria which in turn develop antibiotic resistance. However, inhibition of SOS response can increase recombination activity which in turn leads to genetic variation. The aim of this study was to measure 5 SOS genes expressions in nine E. coli mutants with different MICs for ciprofloxacin following exposure to ciprofloxacin. Gene expression was assessed by quantitative real time PCR. Gene alteration assessment was conducted by PCR amplification and DNA sequencing. Results showed that the expression of recA was increased in 5 mutants. This overexpression is not related to gene alteration, and enhances the expression of polB and umuCD genes encoding nonmutagenic and mutagenic polymerases, respectively. The direct relationship between the level of SOS expression and the level of resistance to ciprofloxacin was also indicated. It was concluded that novel therapeutic strategy that inhibits RecA activity would enhance the efficiency of common antibiotics against pathogenic bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

Antibiotic susceptibility of Estrella lausannensis, a potential emerging pathogen.

PubMed

de Barsy, Marie; Bottinelli, Lavinia; Greub, Gilbert

2014-09-01

Estrella lausannensis is a new Chlamydia-related bacterium, belonging to the Criblamydiaceae family. As suggested by its species name, this bacterium harbors a peculiar star shape. E. lausannensis is able to infect a wide range of amoebal, fish and mammalian cell lines. Moreover, seroprevalence of 2.9% was reported in children and in women with tubal pathology, showing that humans are commonly exposed to this recently discovered strict intracellular bacteria considered as a potential pathogen. Antibiotic susceptibility was determined using two approaches: qPCR and cellular mortality assay. Antibiotics classically used against intracellular bacteria were tested, including β-lactams, fluoroquinolones, cyclines and macrolides. We showed that E. lausannensis is resistant to β-lactams and fluoroquinolones, and sensitive to cyclines. Interestingly, E. lausannensis is slightly resistant to azithromycin with a MIC of 2 μg/ml, which is 10 fold higher compared to Waddlia chondrophila and Parachlamydia acanthamoebae MIC's. A single A2059C mutation in 23S rRNA gene could be responsible for this unexpected resistance. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Cationized Magnetoferritin Enables Rapid Labeling and Concentration of Gram-Positive and Gram-Negative Bacteria in Magnetic Cell Separation Columns

PubMed Central

Spencer, J.; Schwarzacher, W.

2016-01-01

ABSTRACT In order to identify pathogens rapidly and reliably, bacterial capture and concentration from large sample volumes into smaller ones are often required. Magnetic labeling and capture of bacteria using a magnetic field hold great promise for achieving this goal, but the current protocols have poor capture efficiency. Here, we present a rapid and highly efficient approach to magnetic labeling and capture of both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria using cationized magnetoferritin (cat-MF). Magnetic labeling was achieved within a 1-min incubation period with cat-MF, and 99.97% of the labeled bacteria were immobilized in commercially available magnetic cell separation (MACS) columns. Longer incubation times led to more efficient capture, with S. aureus being immobilized to a greater extent than E. coli. Finally, low numbers of magnetically labeled E. coli bacteria (<100 CFU per ml) were immobilized with 100% efficiency and concentrated 7-fold within 15 min. Therefore, our study provides a novel protocol for rapid and highly efficient magnetic labeling, capture, and concentration of both Gram-positive and Gram-negative bacteria. IMPORTANCE Antimicrobial resistance (AMR) is a significant global challenge. Rapid identification of pathogens will retard the spread of AMR by enabling targeted treatment with suitable agents and by reducing inappropriate antimicrobial use. Rapid detection methods based on microfluidic devices require that bacteria are concentrated from large volumes into much smaller ones. Concentration of bacteria is also important to detect low numbers of pathogens with confidence. Here, we demonstrate that magnetic separation columns capture small amounts of bacteria with 100% efficiency. Rapid magnetization was achieved by exposing bacteria to cationic magnetic nanoparticles, and magnetized bacteria were concentrated 7-fold inside the column. Thus, bacterial capture and concentration were achieved within 15 min. This approach could be extended to encompass the capture and concentration of specific pathogens, for example, by functionalizing magnetic nanoparticles with antibodies or small molecule probes. PMID:27060124

Cationized Magnetoferritin Enables Rapid Labeling and Concentration of Gram-Positive and Gram-Negative Bacteria in Magnetic Cell Separation Columns.

PubMed

Correia Carreira, S; Spencer, J; Schwarzacher, W; Seddon, A M

2016-06-15

In order to identify pathogens rapidly and reliably, bacterial capture and concentration from large sample volumes into smaller ones are often required. Magnetic labeling and capture of bacteria using a magnetic field hold great promise for achieving this goal, but the current protocols have poor capture efficiency. Here, we present a rapid and highly efficient approach to magnetic labeling and capture of both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria using cationized magnetoferritin (cat-MF). Magnetic labeling was achieved within a 1-min incubation period with cat-MF, and 99.97% of the labeled bacteria were immobilized in commercially available magnetic cell separation (MACS) columns. Longer incubation times led to more efficient capture, with S. aureus being immobilized to a greater extent than E. coli Finally, low numbers of magnetically labeled E. coli bacteria (<100 CFU per ml) were immobilized with 100% efficiency and concentrated 7-fold within 15 min. Therefore, our study provides a novel protocol for rapid and highly efficient magnetic labeling, capture, and concentration of both Gram-positive and Gram-negative bacteria. Antimicrobial resistance (AMR) is a significant global challenge. Rapid identification of pathogens will retard the spread of AMR by enabling targeted treatment with suitable agents and by reducing inappropriate antimicrobial use. Rapid detection methods based on microfluidic devices require that bacteria are concentrated from large volumes into much smaller ones. Concentration of bacteria is also important to detect low numbers of pathogens with confidence. Here, we demonstrate that magnetic separation columns capture small amounts of bacteria with 100% efficiency. Rapid magnetization was achieved by exposing bacteria to cationic magnetic nanoparticles, and magnetized bacteria were concentrated 7-fold inside the column. Thus, bacterial capture and concentration were achieved within 15 min. This approach could be extended to encompass the capture and concentration of specific pathogens, for example, by functionalizing magnetic nanoparticles with antibodies or small molecule probes. Copyright © 2016 Correia Carreira et al.

[Etiological analysis and establishment of a discriminant model for lower respiratory tract infections in hospitalized patients].

PubMed

Chen, Y S; Lin, X H; Li, H R; Hua, Z D; Lin, M Q; Huang, W S; Yu, T; Lyu, H Y; Mao, W P; Liang, Y Q; Peng, X R; Chen, S J; Zheng, H; Lian, S Q; Hu, X L; Yao, X Q

2017-12-12

Objective: To analyze the pathogens of lower respiratory tract infection(LRTI) including bacterial, viral and mixed infection, and to establish a discriminant model based on clinical features in order to predict the pathogens. Methods: A total of 243 hospitalized patients with lower respiratory tract infections were enrolled in Fujian Provincial Hospital from April 2012 to September 2015. The clinical data and airway (sputum and/or bronchoalveolar lavage) samples were collected. Microbes were identified by traditional culture (for bacteria), loop-mediated isothermal amplification(LAMP) and gene sequencing (for bacteria and atypical pathogen), or Real-time quantitative polymerase chain reaction (Real-time PCR)for viruses. Finally, a discriminant model was established by using the discriminant analysis methods to help to predict bacterial, viral and mixed infections. Results: Pathogens were detected in 53.9% (131/243) of the 243 cases.Bacteria accounted for 23.5%(57/243, of which 17 cases with the virus, 1 case with Mycoplasma pneumoniae and virus), mainly Pseudomonas Aeruginosa and Klebsiella Pneumonia. Atypical pathogens for 4.9% (12/243, of which 3 cases with the virus, 1 case of bacteria and viruses), all were mycoplasma pneumonia. Viruses for 34.6% (84/243, of which 17 cases of bacteria, 3 cases with Mycoplasma pneumoniae, 1 case with Mycoplasma pneumoniae and bacteria) of the cases, mainly Influenza A virus and Human Cytomegalovirus, and other virus like adenovirus, human parainfluenza virus, respiratory syncytial virus, human metapneumovirus, human boca virus were also detected fewly. Seven parameters including mental status, using antibiotics prior to admission, complications, abnormal breath sounds, neutrophil alkaline phosphatase (NAP) score, pneumonia severity index (PSI) score and CRUB-65 score were enrolled after univariate analysis, and discriminant analysis was used to establish the discriminant model by applying the identified pathogens as the dependent variable. The total positive predictive value was 64.7%(77/119), with 66.7% for bacterial infection, 78.0% for viral infection and 33.3% for the mixed infection. Conclusions: The mostly detected pathogens were Pseudomonas aeruginosa, atypitcal pathogens, Klebsiella pneumoniae, influenza A virus and human cytomegalovirus in hospitalized patients with LRTI in this hospital. The discriminant diagnostic model established by clinical features may contribute to predict the pathogens of LRTI.

Antimicrobial Resistance in the Food Chain: A Review

PubMed Central

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

2013-01-01

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

Microbiological evaluation of drinking water sold by roadside vendors of Delhi, India

NASA Astrophysics Data System (ADS)

Chauhan, Abhishek; Goyal, Pankaj; Varma, Ajit; Jindal, Tanu

2017-07-01

Delhi has emerged as one of the greenest capital city of the world. Microbiological assessment of drinking water emphasizes estimation of the hygienic quality of the water sold with reference to community health significance. This study was conducted to evaluate the quality of drinking water sold by roadside vendors in east, west, north and south zones of capital of India. A total number of 36 samples (nine from each zone) were collected as per national guidelines and studied for microbiological assessment. All the drinking water samples were collected in gamma-sterilized bottles and were kept in an ice pack to prevent any significant change in the microbial flora of the samples during the transportation. The water samples were transported to the laboratory in vertical position maintaining the temperature 1-4 °C with ice pack enveloped conditions. Samples were analyzed for total MPN coliform per 100 ml and for the presence and absence of common human pathogenic bacteria such as Escherichia coli, Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa. All the samples were found to be contaminated with coliform organisms in the range of 14 to >1600 per 100 ml of sample. Out of 36 water samples, the occurrence of E. coli was 61 %, Salmonella 25 % S. aureus 14 % and P. aeruginosa 53 % as 22, 9, 5 and 19 samples were found contaminated, respectively. The numbers of coliform bacteria and presence of some common pathogenic bacteria suggested that the quality of drinking water sold by roadside vendors is not within the Indian standard and WHO guidelines laid down for drinking water quality. Hence, there is a vital need to study the root cause in terms of hygiene, sanitation of vendors and source of contamination to prevent waterborne diseases.

Recent Advances in Bacteria Identification by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Using Nanomaterials as Affinity Probes

PubMed Central

Chiu, Tai-Chia

2014-01-01

Identifying trace amounts of bacteria rapidly, accurately, selectively, and with high sensitivity is important to ensuring the safety of food and diagnosing infectious bacterial diseases. Microbial diseases constitute the major cause of death in many developing and developed countries of the world. The early detection of pathogenic bacteria is crucial in preventing, treating, and containing the spread of infections, and there is an urgent requirement for sensitive, specific, and accurate diagnostic tests. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is an extremely selective and sensitive analytical tool that can be used to characterize different species of pathogenic bacteria. Various functionalized or unmodified nanomaterials can be used as affinity probes to capture and concentrate microorganisms. Recent developments in bacterial detection using nanomaterials-assisted MALDI-MS approaches are highlighted in this article. A comprehensive table listing MALDI-MS approaches for identifying pathogenic bacteria, categorized by the nanomaterials used, is provided. PMID:24786089

Recent advances in bacteria identification by matrix-assisted laser desorption/ionization mass spectrometry using nanomaterials as affinity probes.

PubMed

Chiu, Tai-Chia

2014-04-28

Identifying trace amounts of bacteria rapidly, accurately, selectively, and with high sensitivity is important to ensuring the safety of food and diagnosing infectious bacterial diseases. Microbial diseases constitute the major cause of death in many developing and developed countries of the world. The early detection of pathogenic bacteria is crucial in preventing, treating, and containing the spread of infections, and there is an urgent requirement for sensitive, specific, and accurate diagnostic tests. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is an extremely selective and sensitive analytical tool that can be used to characterize different species of pathogenic bacteria. Various functionalized or unmodified nanomaterials can be used as affinity probes to capture and concentrate microorganisms. Recent developments in bacterial detection using nanomaterials-assisted MALDI-MS approaches are highlighted in this article. A comprehensive table listing MALDI-MS approaches for identifying pathogenic bacteria, categorized by the nanomaterials used, is provided.

Microscopic quantification of bacterial invasion by a novel antibody-independent staining method.

PubMed

Agerer, Franziska; Waeckerle, Stephanie; Hauck, Christof R

2004-10-01

Microscopic discrimination between extracellular and invasive, intracellular bacteria is a valuable technique in microbiology and immunology. We describe a novel fluorescence staining protocol, called FITC-biotin-avidin (FBA) staining, which allows the differentiation between extracellular and intracellular bacteria and is independent of specific antibodies directed against the microorganisms. FBA staining of eukaryotic cells infected with Gram-negative bacteria of the genus Neisseria or the Gram-positive pathogen Staphylococcus aureus are employed to validate the novel technique. The quantitative evaluation of intracellular pathogens by the FBA staining protocol yields identical results compared to parallel samples stained with conventional, antibody-dependent methods. FBA staining eliminates the need for cell permeabilization resulting in robust and rapid detection of invasive microbes. Taken together, FBA staining provides a reliable and convenient alternative for the differential detection of intracellular and extracellular bacteria and should be a valuable technical tool for the quantitative analysis of the invasive properties of pathogenic bacteria and other microorganisms.

Antibiotic resistance and biofilm tolerance: a combined threat in the treatment of chronic infections.

PubMed

Bowler, Philip G

2018-05-02

Since the introduction of antibiotics into human medicine in the 1940's, antibiotic resistance has emerged at an alarming rate and is now a major threat to public health. This problem is amplified by pathogenic bacteria existing most commonly in biofilm form, creating additional bacterial tolerance to antimicrobial agents. Biofilm is now considered to be a primary cause of chronic infection, and antibiotic-resistant bacteria are prevalent in biofilm form. In particular, chronic non-healing wounds commonly harbour complex polymicrobial, pathogenic biofilm that is tolerant to systemic and topical antimicrobial therapy. Antibiotic stewardship programmes have emerged globally to improve antibiotic prescribing practices, and to curb the emergence and spread of bacterial resistance. In this regard, new antimicrobial strategies must be considered, one of which is to use antibiofilm/antimicrobial combinations to disrupt biofilm, thereby facilitating effectiveness of antimicrobial agents, and reducing the opportunity for antibiotic resistance gene transfer within biofilm. This strategy is being considered in several clinical conditions, one of which is chronic non-healing wounds, where antibiotics are used excessively and often indiscriminately. A combination antibiofilm/antimicrobial wound dressing has been shown to facilitate healing in previously biofilm-impaired non-healing wounds. This approach must be considered as part of antibiotic stewardship programmes to reduce the usage and implications of antibiotic therapy, and improve outcomes associated with chronic infections.

Investigation for zoonotic disease pathogens (Aeromonas hydrophila, Pseudomonas fluorescens, Streptococcus iniae) seen in carp farms in Duhok region of Northern Iraq by molecular methods

NASA Astrophysics Data System (ADS)

Mohammed, Kamiran Abdulrahman; Arabacı, Muhammed; Önalan, Şükrü

2017-04-01

The aim of this study was to determine the zoonotic bacteria in carp farms in Duhok region of the Northern Iraq. Carp is the main fish species cultured in the Duhok region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 20 carp farms in the Duhok Region of the Northern Iraq. Six carp samples were collected from each carp farm. Head kidney tissue samples and intestine tissue samples were collected from each carp sample. Than head kidney and intestine tissue samples were pooled. The total bacterial DNA extraction from the pooled each 20 head kidney tissue samples and pooled each 20 intestinal tissue samples. Primers for pathogens were originally designed from 16S Ribosomal gene region. Zoonotic bacteria were scanned in all tissue samples by absent / present analysis in the RT-PCR. After RT-PCR, Capillary gel electrophoresis bands were used for the confirmation of the size of amplicon which was planned during primer designing stage. As a result, one sample was positive in respect to Aeromonas hydrophila, from intestine and one carp farm was positive in respect to Pseudomonas fluorescens from intestine and two carp farms were positive in respect to Streptococcus iniae. Totally 17 of 20 carp farms were negative in respect to the zoonotic bacteria. In conclusion the zoonotic bacteria were very low (15 %) in carp farms from the Duhok Region in the Northern Iraq. Only in one Carp farms, both Aeromonas hydrophila and Pseudomonas fluorescens were positive. Also Streptococcus inia were positive in two carp farms.

Investigation of zoonotic disease pathogens (Aeromonas hydrophila, Pseudomonas fluorescens, Streptococcus iniae) seen in carp farms in the Northern Iraq-Erbil region by molecular methods

NASA Astrophysics Data System (ADS)

Ibraheem, Azad Saber; Önalan, Şükrü; Arabacı, Muhammed

2017-04-01

The aim of this study was to determine the zoonotic bacteria in carp farms in the Northern Iraq-Erbil region. Carp is the main fish species cultured in Erbil region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 25 carp farms in the Northern Iraq-Erbil region. Six carp samples were collected from each carp farm. Head kidney and intestine tissue samples were collected from each carp sample. Then head kidney and intestine tissue samples were pooled separately from each carp farm. Total bacterial DNA had been extracted from the 25 pooled head kidney and 25 intestinal tissue samples. The pathogen Primers were originally designed from 16S RNA gene region. Zoonotic bacteria were scanned in all tissue samples with absent/present analysis by RT-PCR. Furthermore, the capillary gel electrophoresis bands were used for confirmation of amplicon size which was planned during primer designing stage. As a result, thirteen carp farms were positive in the respect to Aeromonas hydrophila, eight carp farms were positive from head kidney and six carp farms were positive from the intestine, only one carp farm was positive from both head kidney and the intestine tissue samples. In the respect to Streptococcus iniae, four carp farms were positive from head kidney and two carp farms were positive from the intestine. Only one carp farm was positive in the respect to Pseudomonas fluorescens from the intestine. Totally, 9 of 25 carp farms were cleared (negative) the zoonotic bacteria. In conclusion, the zoonotic bacteria were high (64 %) in carp farms in the Northern Iraq-Erbil region.

Antibacterial Activities of Hibiscus sabdariffa Extracts and Chemical Sanitizers Directly on Green Leaves Contaminated with Foodborne Pathogens.

PubMed

Gómez-Aldapa, Carlos A; Rangel-Vargas, Esmeralda; Torres-Vitela, Ma Refugio; Villarruel-López, Angélica; Acevedo-Sandoval, Otilio A; Gordillo-Martínez, Alberto J; Godínez-Oviedo, Angélica; Castro-Rosas, Javier

2018-02-01

Leafy greens have been associated with foodborne disease outbreaks in different countries. To decrease microbial contamination of leafy greens, chemical agents are commonly used; however, a number of studies have shown these agents to have limited antimicrobial effect against pathogenic bacteria on vegetables. The objective of this study was to compare the antibacterial effect of Hibiscus sabdariffa calyx extracts (water, methanol, acetone, and ethyl acetate), sodium hypochlorite, acetic acid, and colloidal silver against foodborne bacteria on leafy greens. Thirteen foodborne bacteria were used in the study: Listeria monocytogenes, Shigella flexneri, Salmonella serotypes Typhimurium Typhi, and Montevideo, Staphylococcus aureus, Escherichia coli O157:H7, five E. coli pathotypes (Shiga toxin-producing, enteropathogenic, enterotoxigenic, enteroinvasive, and enteroaggregative), and Vibrio cholerae O1. Each foodborne bacterium was separately inoculated on romaine lettuce, spinach, and coriander leaves. Separately, contaminated leafy greens were immersed in four hibiscus extracts and in sanitizers for 5 min. Next, green leaves were washed with sterile tap water. Separately, each green leaf was placed in a bag that contained 0.1% sterile peptone water and was rubbed for 2 min. Counts were done by plate count using appropriate dilutions (in sterile peptone water) of the bacterial suspensions spread on Trypticase soy agar plates and incubated at 35 ± 2°C for 48 h. Statistically significant differences ( P < 0.05) were calculated with an analysis of variance and Duncan's test. All 13 foodborne bacteria attached to leafy greens. Roselle calyx extracts caused a significantly greater reduction ( P < 0.05) in concentration of all foodborne bacteria on contaminated romaine lettuce, spinach, and coriander than did the sodium hypochlorite, colloidal silver, and acetic acid. Dry roselle calyx extracts may potentially be a useful addition to disinfection procedures for romaine lettuce, spinach, and coriander.

Microorganisms and heavy metals associated with atmospheric deposition in a congested urban environment of a developing country: Sri Lanka.

PubMed

Weerasundara, Lakshika; Amarasekara, R W K; Magana-Arachchi, D N; Ziyath, Abdul M; Karunaratne, D G G P; Goonetilleke, Ashantha; Vithanage, Meththika

2017-04-15

The presence of bacteria and heavy metals in atmospheric deposition were investigated in Kandy, Sri Lanka, which is a typical city in the developing world with significant traffic congestion. Atmospheric deposition samples were analyzed for Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb which are heavy metals common to urban environments. Al and Fe were found in high concentrations due to the presence of natural sources, but may also be re-suspended by vehicular traffic. Relatively high concentrations of toxic metals such as Cr and Pb in dissolved form were also found. High Zn loads can be attributed to vehicular emissions and the wide use of Zn coated roofing materials. The metal loads in wet deposition showed higher concentrations compared to dry deposition. The metal concentrations among the different sampling sites significantly differ from each other depending on the traffic conditions. Industrial activities are not significant in Kandy City. Consequently, the traffic exerts high influence on heavy metal loadings. As part of the bacterial investigations, nine species of culturable bacteria, namely; Sphingomonas sp., Pseudomonas aeruginosa, Pseudomonas monteilii, Klebsiella pneumonia, Ochrobactrum intermedium, Leclercia adecarboxylata, Exiguobacterium sp., Bacillus pumilus and Kocuria kristinae, which are opportunistic pathogens, were identified. This is the first time Pseudomonas monteilii and Ochrobactrum intermedium has been reported from a country in Asia. The culturable fraction constituted ~0.01 to 10%. Pigmented bacteria and endospore forming bacteria were copious in the atmospheric depositions due to their capability to withstand harsh environmental conditions. The presence of pathogenic bacteria and heavy metals creates potential human and ecosystem health risk. Copyright © 2017 Elsevier B.V. All rights reserved.

Inactivation of Gram-negative and Gram-positive bacteria in red cell concentrates using INACTINE PEN110 chemistry.

PubMed

Zavizion, B; Serebryanik, D; Chapman, J; Alford, B; Purmal, A

2004-10-01

The risk of transfusion-transmitted bacterial infections as a result of the presence of bacteria in blood is one of the major concerns in transfusion medicine. The purpose of this study was to investigate whether bacteria inoculated into red blood cell concentrates can be inactivated by the INACTINE PEN110 pathogen-reduction process. Four bacterial species were chosen for the study: anaerobic Gram-positive Clostridium perfringens and Propionibacterium acnes, known to be transfusion-transmitted; and two Gram-negative species, Acinetobacter johnsonii and Acinetobacter lwoffii, recently reported to be a common cause of transfusion-associated infections in Europe. Identical units of leucoreduced red cell concentrates were inoculated with A. johnsonii, A. lwoffii, C. perfringens, or P. acnes. The 4 degrees C control units were put on storage immediately after receiving the spike. The test units were subjected to PEN110 treatment and then stored. The bacterial titre in all units was monitored during a 6-week storage period. The PEN110 inactivation of all tested bacterial strains was time- and titre-dependent. For A. johnsonii and A. lwoffii, no viable bacteria were detected in the units spiked with up to 10(4) colony-forming units (CFU)/ml and treated with PEN110. For red cell units spiked with 10(4)-10(5) CFU/ml of C. perfringens and P. acnes, no viable bacteria were detected in the units treated with PEN110. In control units, there was a gradual decrease in A. johnsonii, A. lwoffii and C. perfringens titres during cold storage, while P. acnes titres remained stable. The PEN110 pathogen-reduction process was demonstrated to inactivate high titres of A. johnsonii, A. lwoffii, C. perfringens and P. acnes in red cell concentrates.

Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper.

PubMed

Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

2012-07-01

Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks.

Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper

PubMed Central

Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

2012-01-01

Background and Aims Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Methods Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Key Results Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. Conclusions The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks. PMID:22437662

Aetiology of acute paediatric gastroenteritis in Bulgaria during summer months: prevalence of viral infections.

PubMed

Mladenova, Zornitsa; Steyer, Andrej; Steyer, Adela Fratnik; Ganesh, Balasubramanian; Petrov, Petar; Tchervenjakova, Tanja; Iturriza-Gomara, Miren

2015-03-01

Paediatric acute gastroenteritis is a global public health problem. Comprehensive laboratory investigation for viral, bacterial and parasitic agents is helpful for improving management of acute gastroenteritis in health care settings and for monitoring and controlling the spread of these infections. Our study aimed to investigate the role of various pathogens in infantile diarrhoea in Bulgaria outside the classical winter epidemics of rotavirus and norovirus. Stool samples from 115 hospitalized children aged 0-3 years collected during summer months were tested for presence of 14 infectious agents - group A rotavirus, astrovirus, Giardia, Cryptosporidium and Entamoeba using ELISAs; norovirus by real-time RT-PCR; picobirnavirus and sapovirus by RT-PCR; adenovirus using PCR, and Salmonella, Shigella, Escherichia coli, Yersinia and Campylobacter using standard bacterial cultures. Infectious origin was established in a total of 92 cases and 23 samples remained negative. A single pathogen was found in 67 stools, of which rotaviruses were the most prevalent (56.7 %), followed by noroviruses (19.4 %), enteric adenoviruses (7.5 %), astroviruses (6.0 %), bacteria and parasites (4.5 % each) and sapoviruses (1.4 %). Rotavirus predominant genotypes were G4P[8] (46.3 %) and G2P[4] (21.4 %); for astroviruses, type 1a was the most common, while the GII.4/2006b variant was the most prevalent among noroviruses. Bacteria were observed in five cases, with Salmonella sp. as the most prevalent, while parasites were found in ten stool samples, with Giardia intestinalis in five cases. The results demonstrated high morbidity associated with viral infections and that rotavirus and norovirus remain the most common pathogens associated with severe gastroenteritis during summer months in Bulgaria, a country with a temperate climate, and significant molecular diversity among circulating virus strains. © 2015 The Authors.

Relationship between lactobacilli and opportunistic bacterial pathogens associated with vaginitis.

PubMed

Razzak, Mohammad Sabri A; Al-Charrakh, Alaa H; Al-Greitty, Bara Hamid

2011-04-01

Vaginitis, is an infectious inflammation of the vaginal mucosa, which sometimes involves the vulva. The balance of the vaginal flora is maintained by the Lactobacilli and its protective and probiotic role in treating and preventing vaginal infection by producing antagonizing compounds which are regarded as safe for humans. The aim of this study was to evaluate the protective role of Lactobacilli against common bacterial opportunistic pathogens in vaginitis and study the effects of some antibiotics on Lactobacilli isolates. In this study (110) vaginal swabs were obtained from women suffering from vaginitis who admitted to Babylon Hospital of Maternity and Paediatrics in Babylon province, Iraq. The study involved the role of intrauterine device among married women with vaginitis and also involved isolation of opportunistic bacterial isolates among pregnant and non pregnant women. This study also involved studying probiotic role of Lactobacilli by production of some defense factors like hydrogen peroxide, bacteriocin, and lactic acid. Results revealed that a total of 130 bacterial isolates were obtained. Intrauterine device was a predisposing factor for vaginitis. The most common opportunistic bacterial isolates were Staphylococcus aureus, Escherichia coli, Streptococcus agalactiae, and Klebsiella pneumoniae. All Lactobacilli were hydrogen peroxide producers while some isolates were bacteriocin producers that inhibited some of opportunistic pathogens (S. aureus, E. coli). Lactobacilli were sensitive to erythromycin while 93.3% of them were resistant to ciprofloxacin and (40%, 53.3%) of them were resistant to amoxicillin and gentamycin respectively. Results revealed that there was an inverse relationship between Lactobacilli presence and organisms causing vaginitis. This may be attributed to the production of defense factors by Lactobacilli. The types of antibiotics used to treat vaginitis must be very selective in order not to kill the beneficial bacteria (Lactobacilli) that help in preservation of vaginal health and ecosystem as being one of the probiotic bacteria.

The effects of competition from non-pathogenic foodborne bacteria during the selective enrichment of Listeria monocytogenes using buffered Listeria enrichment broth☆

PubMed Central

Dailey, Rachel C.; Martin, Keely G.; Smiley, R. Derike

2016-01-01

The growth of Listeria monocytogenes during the pathogen specific enrichment of food samples can be limited by the presence of additional microorganisms that are resistant to the selective conditions being applied. If growth is severely limited and minimum post-enrichment threshold levels are not met then the presence of L. monocytogenes may go undetected. Several food products were screened for non-pathogenic commensal or spoilage microorganisms that are capable of growth under the conditions commonly used by regulatory testing laboratories to select for Listeria species. The effect of these potential competitor microorganisms on the ability to detect L. monocytogenes by several common molecular screening assays was then determined. Eight species of bacteria were isolated from foods that demonstrated the ability to grow in buffered Listeria enrichment broth under selective conditions. Growth of these competitor microorganisms during the enrichment incubation resulted in a decrease ranging from 1 to 4 logs in the 48 h population of L. monocytogenes. Three strains of L. monocytogenes representing serotypes 1/2a, 1/2b, and 4b were included in this study but no one serotype appeared to be most or least sensitive to the presence of competitor microorganisms. One additional strain of L. monocytogenes was identified as displaying minimal growth during the enrichment period in the presence of the Citrobacter braakii with the final population only reaching approximately 2.6 log CFU/ml after 48 h which was a 2 log increase over the initial population. This particular strain was subsequently shown to be difficult to detect following enrichment by an automated immunofluorescence assay and an antibody-based lateral flow device assay. In some enrichments, this strain was also difficult to detect by real-time PCR. PMID:25084660

Targeting human pathogenic bacteria by siderophores: A proteomics review.

PubMed

Ferreira, Daniela; Seca, Ana M L; C G A, Diana; Silva, Artur M S

2016-08-11

Human bacterial infections are still a major public health problem throughout the world. Therefore it is fundamental to understand how pathogenic bacteria interact with their human host and to develop more advanced drugs or vaccines in response to the increasing bacterial resistance. Since iron is essential to bacterial survival and growth inside the host tissues, these microorganisms have developed highly efficient iron-acquisition systems; the most common one involves the secretion of iron chelators into the extracellular environment, known as siderophores, and the corresponding siderophore-membrane receptors or transporters responsible for the iron uptake. In the past few decades, several biochemical methods and genetic screens have been employed to track down and identify these iron-scavenging molecules. However, compared with the previous "static" approaches, proteomic identification is revealing far more molecules through full protein mapping and becoming more rapid and selective, leading the scientific and medical community to consider standardizing proteomic tools for clinical biomarker detection of bacterial infectious diseases. In this review, we focus on human pathogenic Gram-negative bacteria and discuss the importance of siderophores in their virulence and the available proteomic strategies to identify siderophore-related proteins and their expression level under different growth conditions. The promising use of siderophore antibiotics to overcome bacterial resistance and the future of proteomics in the routine clinical care are also mentioned. Proteomic strategies to identify siderophore-related proteins and their expression level can be helpful to control and/or find a cure of infectious deseases especially if related with multidrug resistance. Siderophores are low-molecular-weight compounds produced by bacteria which can become clinical biomarkers and/or antibiotics used mainly in "Trojan horse" type strategies. Due to the above mention we think that the promising use of siderophore to overcome bacterial resistance and the future of proteomics in the routine clinical care is a hot topic that should be discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of a watershed model (HSPF) for evaluating sources and transport of pathogen indicators in the Chino Basin drainage area, San Bernardino County, California

USGS Publications Warehouse

Hevesi, Joseph A.; Flint, Lorraine E.; Church, Clinton D.; Mendez, Gregory O.

2011-01-01

A watershed model using Hydrologic Simulation Program-FORTRAN (HSPF) was developed for the urbanized Chino Basin in southern California to simulate the transport of pathogen indicator bacteria, evaluate the flow-component and land-use contributions to bacteria contamination and water-quality degradation throughout the basin, and develop a better understanding of the potential effects of climate and land-use change on water quality. The calibration of the model for indicator bacteria was supported by historical data collected before this study and by samples collected by the U.S. Geological Survey from targeted land-use areas during storms in water-year 2004. The model was successfully calibrated for streamflow at 5 gage locations representing the Chino Creek and Mill Creek drainages. Although representing pathogens as dissolved constituents limits the model's ability to simulate the transport of pathogen indicator bacteria, the bacteria concentrations measured over the period 1998-2004 were well represented by the simulated concentrations for most locations. Hourly concentrations were more difficult to predict because of high variability in measured bacteria concentrations. In general, model simulations indicated that the residential and commercial land uses were the dominant sources for most of the pathogen indicator bacteria during low streamflows. However, simulations indicated that land used for intensive livestock (dairies and feedlots) and mixed agriculture contributed the most bacteria during storms. The calibrated model was used to evaluate how various land use, air temperature, and precipitation scenarios would affect flow and transport of bacteria. Results indicated that snow pack formation and melt were sensitive to changes in air temperature in the northern, mountainous part of the Chino Basin, causing the timing and magnitude of streamflow to shift in the natural drainages and impact the urbanized areas of the central Chino Basin. The relation between bacteria concentrations and air temperature was more complicated, and did not substantially affect the quality of water discharging from the Chino Basin into the Santa Ana River. Changes in precipitation had a greater basin-wide affect on bacteria concentrations than changes in air temperature, and varied according to location. Drainages representing natural conditions had a decrease in bacteria concentrations in correlation with an increase in precipitation, whereas drainages in the central and southern part of the Chino Basin had an increase in bacteria concentrations. Drier climate conditions tended to result in higher sensitivity of simulated bacteria concentrations to changes in precipitation. Simulated bacteria concentrations in wetter climates were usually less sensitive to changes in precipitation because bacteria transport becomes more dependent on the land-use specified bacteria loading rates and the storage limits. Bacteria contamination from impervious-area runoff is affected to a greater degree by drier climates, whereas contamination from pervious-area runoff is affected to a greater degree by wetter climates. Model results indicated that the relation between precipitation, runoff, and bacteria contamination is complicated because after the initial bacteria washoff and transport from the land surfaces during the beginning of a storm period, subsequent runoff has fewer bacteria available for washoff, which then dilutes the concentrations of bacteria in the downstream reach. It was illustrated that pathogen indicator bacteria transport depends most significantly on the relation of imperviousness to runoff, which controls the frequency, and often the magnitude, of transport, and on the contribution of higher bacteria loading rates used for pervious land areas, especially intensive feedlots, to the infrequent, but very high, peaks of bacteria contamination. The indicator bacteria transport model for the Chino Basin was based on the assumption that no

A rapid two dot filter assay for the detection of E. coli O157 in water samples.

PubMed

Kamma, Sujatha; Tang, Lily; Leung, Kelvin; Ashton, Edie; Newman, Norman; Suresh, Mavanur R

2008-07-31

E. coli O157:H7 is an enterohemorrhagic bacteria that cause deadly water-borne infections implicated in outbreaks of a wide spectrum of human gastrointestinal diseases. It is therefore important to have a rapid convenient, simple and sensitive range of detection of E. coli O157:H7. A new E. coli O157 MAb designated P124 was developed for ultrasensitive detection of E. coli O157 in water, apple juice and beef for routine use. A prototype filter dot assay was designed with anti-E. coli O157 MAb bound to 0.2 microm nitrocellulose filter disk as the capture antibody. A 100 ml water sample spiked with 1-50 CFU of E. coli O157 either in the presence or absence of other non-specific bacteria were filtered for capture of the pathogen on the antibody coated nitrocellulose disk. The detection of the pathogen was successfully accomplished by the same antibody both as a capture and detecting antibody as a homosandwich. In a non-enriched format, detection of E. coli was possible with a sensitivity of 2500 CFU/100 ml. Ultrasensitive detection of ~1 CFU/100 ml sample could be achieved by a prior pathogen enrichment step before the addition of the labeled antibody. The design of this diagnostic test is based on the common architecture of all bacteria, viruses and spores, namely the manifestation of repeat lipopolysaccharide epitopes on the surface. We have developed an easy-to-use two dot visual filter assay for translation into current water testing in public health laboratories to detect E. coli O157:H7. In a 5 h assay approximately 1 CFU and approximately 5 CFU of E. coli O157 could be detected in 100 ml of water or juice and lake samples respectively. This simple homosandwich enrichment strategy can also be used to detect low levels of other water-borne pathogens.

Antimicrobial activity of spices.

PubMed

Arora, D S; Kaur, J

1999-08-01

Spices have been shown to possess medicinal value, in particular, antimicrobial activity. This study compares the sensitivity of some human pathogenic bacteria and yeasts to various spice extracts and commonly employed chemotherapeutic substances. Of the different spices tested only garlic and clove were found to possess antimicrobial activity. The bactericidal effect of garlic extract was apparent within 1 h of incubation and 93% killing of Staphylococcus epidermidis and Salmonella typhi was achieved within 3 h. Yeasts were totally killed in 1 h by garlic extract but in 5 h with clove. Some bacteria showing resistance to certain antibiotics were sensitive to extracts of both garlic and clove. Greater anti-candidal activity was shown by garlic than by nystatin. Spices might have a great potential to be used as antimicrobial agents.

Analysis of fungal type isolates taken from a 90-day manned test of an advanced regenerative life support system

NASA Technical Reports Server (NTRS)

Sofios, M.; Swatek, F. E.

1972-01-01

Fungal-like cultures isolated before, during, and after the 90-day test from samples of space station simulator (SSS) atmosphere, surfaces, subsystem componets, and crew dermal sites were identified to genus. Out of the original 525 isolates, approximately 80% were classified as bacteria. Laboratory methods (culture media, moisturization, and incubation temperatures) favored the recovery of medically significant bacteria rather than fungi. Therefore, fungal isolates were mostly, nonfastidious types which are ubiquitous in soil and air and commonly contaminate laboratory cultures of pathogens. Predominant isolates were species of Aspergillus, Penicillium, Pullularia, Rhodotorula, and various yeasts. No instances of fungal proliferation were observed; test data reflect the survival of environmental types indigenous to the SSS pretests.

Assessment of bacterial contamination of lipstick using pyrosequencing.

PubMed

Lee, So Y; Lee, Si Y

As soon as they are exposed to the environment, cosmetics become contaminated with microorganisms, and this contamination accumulates with increased use. In this study, we employed pyrosequencing to investigate the diversity of bacteria found on lipstick. Bacterial DNA was extracted from 20 lipstick samples and mixed in equal ratios for pyrosequencing analysis. As a result, 105 bacterial genera were detected, four of which ( Leifsonia , Methylobacterium , Streptococcus , and Haemophilus ) were predominant in 92% of the 19,863 total sequence reads. Potentially pathogenic genera such as Staphylococcus , Pseudomonas , Escherichia , Salmonella , Corynebacterium , Mycobacterium , and Neisseria accounted for 27.6% of the 105 genera. The most commonly identified oral bacteria belonged to the Streptococcus genus, although other oral genera such as Actinomyces , Fusobacterium , Porphyromonas , and Lactobacillus were also detected.

Entomopathogenicity to Two Hemipteran Insects Is Common but Variable across Epiphytic Pseudomonas syringae Strains.

PubMed

Smee, Melanie R; Baltrus, David A; Hendry, Tory A

2017-01-01

Strains of the well-studied plant pathogen Pseudomonas syringae show large differences in their ability to colonize plants epiphytically and to inflict damage to hosts. Additionally, P. syringae can infect some sap-sucking insects and at least one P. syringae strain is highly virulent to insects, causing death to most individuals within as few as 4 days and growing to high population densities within insect hosts. The likelihood of agricultural pest insects coming into contact with transient populations of P. syringae while feeding on plants is high, yet the ecological implications of these interactions are currently not well understood as virulence has not been tested across a wide range of strains. To investigate virulence differences across strains we exposed the sweet potato whitefly, Bemisia tabaci , and the pea aphid, Acyrthosiphon pisum , both of which are cosmopolitan agricultural pests, to 12 P. syringae strains. We used oral inoculations with bacteria suspended in artificial diet in order to assay virulence while controlling for other variables such as differences in epiphytic growth ability. Generally, patterns of pathogenicity remain consistent across the two species of hemipteran insects, with bacterial strains from phylogroup II, or genomospecies 1, causing the highest rate of mortality with up to 86% of individuals dead after 72 h post infection. The rate of mortality is highly variable across strains, some significantly different from negative control treatments and others showing no discernable difference. Interestingly, one of the most pathogenic strains to both aphids and whiteflies (Cit7) is thought to be non-pathogenic on plants. We also found Cit7 to establish the highest epiphytic population after 48 h on fava beans. Between the nine P. syringae strains tested for epiphytic ability there is also much variation, but epiphytic ability was positively correlated with pathogenicity to insects, suggesting that the two traits may be linked and that strains likely to be found on plants may often be entomopathogenic. Our study highlights that there may be a use for epiphytic bacteria in the biological control of insect crop pests. It also suggests that interactions with epiphytic bacteria could be evolutionary and ecological drivers for hemipteran insects.

Pathogenicity Island Cross Talk Mediated by Recombination Directionality Factors Facilitates Excision from the Chromosome.

PubMed

Carpenter, Megan R; Rozovsky, Sharon; Boyd, E Fidelma

2015-12-14

Pathogenicity islands (PAIs) are mobile integrated genetic elements (MIGEs) that contain a diverse range of virulence factors and are essential in the evolution of pathogenic bacteria. PAIs are widespread among bacteria and integrate into the host genome, commonly at a tRNA locus, via integrase-mediated site-specific recombination. The excision of PAIs is the first step in the horizontal transfer of these elements and is not well understood. In this study, we examined the role of recombination directionality factors (RDFs) and their relationship with integrases in the excision of two PAIs essential for Vibrio cholerae host colonization: Vibrio pathogenicity island 1 (VPI-1) and VPI-2. VPI-1 does not contain an RDF, which allowed us to answer the question of whether RDFs are an absolute requirement for excision. We found that an RDF was required for efficient excision of VPI-2 but not VPI-1 and that RDFs can induce excision of both islands. Expression data revealed that the RDFs act as transcriptional repressors to both VPI-1- and VPI-2-encoded integrases. We demonstrated that the RDFs Vibrio excision factor A (VefA) and VefB bind at the attachment sites (overlapping the int promoter region) of VPI-1 and VPI-2, thus supporting this mode of integrase repression. In addition, V. cholerae RDFs are promiscuous due to their dual functions of promoting excision of both VPI-1 and VPI-2 and acting as negative transcriptional regulators of the integrases. This is the first demonstration of cross talk between PAIs mediated via RDFs which reveals the complex interactions that occur between separately acquired MIGEs. Deciphering the mechanisms of pathogenicity island excision is necessary for understanding the evolution and spread of these elements to their nonpathogenic counterparts. Such mechanistic insight would assist in predicting the mobility of uncharacterized genetic elements. This study identified extensive RDF-mediated cross talk between two nonhomologous VPIs and demonstrated the dual functionality of RDF proteins: (i) inducing PAI excision and (ii) acting as transcriptional regulators. Findings from this study may be implicated in determining the mobilome contribution of other bacteria with multiple MIGEs. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Specific detection of Pectobacterium carotovorum by loop-mediated isothermal amplification.

PubMed

Yasuhara-Bell, Jarred; Marrero, Glorimar; De Silva, Asoka; Alvarez, Anne M

2016-12-01

Potatoes are an important agroeconomic crop worldwide and maceration diseases caused by pectolytic bacterial pathogens result in significant pre- and post-harvest losses. Pectobacterium carotovorum shares a common host range with other Pectobacterium spp. and other members of the Enterobacteriaceae, such as Dickeya spp. As these pathogens cannot be clearly differentiated on the basis of the symptoms they cause, improved methods of identification are critical for the determination of sources of contamination. Current standardized methods for the differentiation of pectolytic species are time consuming and require trained personnel, as they rely on traditional bacteriological practices that do not always produce conclusive results. In this growing world market, there is a need for rapid diagnostic tests that can differentiate between pectolytic pathogens, as well as separate them from non-pectolytic enteric bacteria associated with soft rots of potato. An assay has been designed previously to detect the temperate pathogen Pectobacterium atrosepticum, but there is currently no recognized rapid assay for the detection of the tropical/subtropical counterpart, Pectobacterium carotovorum. This report describes the development of a loop-mediated isothermal amplification (LAMP) assay that detects P. carotovorum with high specificity. The assay was evaluated using all known species of Pectobacterium and only showed positive reactions for P. carotovorum. This assay was also tested against 15 non-target genera of plant-associated bacteria and did not produce any false positives. The LAMP assay described here can be used as a rapid test for the differentiation of P. carotovorum from other pectolytic pathogens, and its gene target can be the basis for the development of other molecular-based detection assays. © 2016 BSPP and John Wiley & Sons Ltd.

Hemocytes from Pediculus humanus humanus are hosts for human bacterial pathogens

PubMed Central

Coulaud, Pierre-Julien; Lepolard, Catherine; Bechah, Yassina; Berenger, Jean-Michel; Raoult, Didier; Ghigo, Eric

2015-01-01

Pediculus humanus humanus is an human ectoparasite which represents a serious public health threat because it is vector for pathogenic bacteria. It is important to understand and identify where bacteria reside in human body lice to define new strategies to counterstroke the capacity of vectorization of the bacterial pathogens by body lice. It is known that phagocytes from vertebrates can be hosts or reservoirs for several microbes. Therefore, we wondered if Pediculus humanus humanus phagocytes could hide pathogens. In this study, we characterized the phagocytes from Pediculus humanus humanus and evaluated their contribution as hosts for human pathogens such as Rickettsia prowazekii, Bartonella Quintana, and Acinetobacter baumannii. PMID:25688336

The Use of Predatory Bacteria to Control Select Pathogens and Treat Respiratory Infections

DTIC Science & Technology

2015-04-13

Monnappa, A. K. & Mitchell, R. J. The dual probiotic and antibiotic nature of Bdellovibrio bacteriovorus. BMB Rep 45, 71-78, doi:10.5483/BMBRep...Perdigon, G. Gut immune stimulation by non pathogenic Gram(+) and Gram(-) bacteria. Comparison with a probiotic strain. Cytokine 41, 223-231, doi:10.1016

A COMPARISON OF THREE ASSAY PROCEDURES FOR DETERMINING CHLORINE INACTIVATION OF WATERBORNE PATHOGENIC BACTERIA

EPA Science Inventory

One criterion on which chlorine treatment of water may be based is the concentration (C) in mg/l multiplied by the time (t) in min of exposure or Ct values. We compared different Ct values on waterborne pathogenic bacteria by cultural assay for viability and 2 assays that mea...

Human pathogens in plant biofilms: Formation, physiology, and detection

USDA-ARS?s Scientific Manuscript database

Fresh produce, viewed as an essential part of a healthy life style is usually consumed in the form of raw or minimally processed fruits and vegetables, and is a potentially important source of food-borne human pathogenic bacteria and viruses. These are passed on to the consumer since the bacteria ca...

Lack of direct effects of agrochemicals on zoonotic pathogens and fecal indicator bacteria.

PubMed

Staley, Zachery R; Senkbeil, Jacob K; Rohr, Jason R; Harwood, Valerie J

2012-11-01

Agrochemicals, fecal indicator bacteria (FIB), and pathogens frequently contaminate water simultaneously. No significant direct effects of fertilizer, atrazine, malathion, and chlorothalonil on the survival of Escherichia coli, Enterococcus faecalis, Salmonella enterica, human polyomaviruses, and adenovirus were detected, supporting the assertion that previously observed effects of agrochemicals on FIB were indirect.

Cultivation and qPCR detection of pathogenic and antibiotic resistant bacteria establishment in naive broiler houses

USDA-ARS?s Scientific Manuscript database

: Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space, atop bedding material such as pine shavings or rice hulls, for approximately 6.5 weeks. This environment is known for harboring pathogens and antibiotic resistant bacteria, but ...

Fast detection of Listeria monocytogenes through a nanohybrid quantum dot complex.

PubMed

Donoso, Wendy; Castro, Ricardo I; Guzmán, Luis; López-Cabaña, Zoraya; Nachtigall, Fabiane M; Santos, Leonardo S

2017-09-01

Listeria monocytogenes is a recognized foodborne pathogen that causes listeriosis in susceptible consumers. Currently, the detection systems for Listeria in food detect live and dead bacteria, being the viable microorganisms most relevant for their ability to cause sickness in the population at risk. For this reason, a new nanohybrid compound was developed for the optical detection of Listeria that was based on polyamidoamine dendrimers functionalized with an auxotrophic cofactor (lipoic acid), together with the coupling of fluorescent semiconductor crystals (quantum dots). The nanohybrid sensor has a detection limit for viable L. monocytogenes of 5.19 × 10 3 colony-forming units per milliliter under epifluorescence microscopy. It was specific when used among other pathogens commonly found in food.

Immune evasion by pathogens of bovine respiratory disease complex.

PubMed

Srikumaran, Subramaniam; Kelling, Clayton L; Ambagala, Aruna

2007-12-01

Bovine respiratory tract disease is a multi-factorial disease complex involving several viruses and bacteria. Viruses that play prominent roles in causing the bovine respiratory disease complex include bovine herpesvirus-1, bovine respiratory syncytial virus, bovine viral diarrhea virus and parinfluenza-3 virus. Bacteria that play prominent roles in this disease complex are Mannheimia haemolytica and Mycoplasma bovis. Other bacteria that infect the bovine respiratory tract of cattle are Histophilus (Haemophilus) somni and Pasteurella multocida. Frequently, severe respiratory tract disease in cattle is associated with concurrent infections of these pathogens. Like other pathogens, the viral and bacterial pathogens of this disease complex have co-evolved with their hosts over millions of years. As much as the hosts have diversified and fine-tuned the components of their immune system, the pathogens have also evolved diverse and sophisticated strategies to evade the host immune responses. These pathogens have developed intricate mechanisms to thwart both the innate and adaptive arms of the immune responses of their hosts. This review presents an overview of the strategies by which the pathogens suppress host immune responses, as well as the strategies by which the pathogens modify themselves or their locations in the host to evade host immune responses. These immune evasion strategies likely contribute to the failure of currently-available vaccines to provide complete protection to cattle against these pathogens.

[Distribution and drug resistance of the pathogenic bacteria from sputum specimens of 1 125 children with tracheo bronchial foreign bodies].

PubMed

Wen, Xin; Su, Jinzhu; Cui, Li; Wang, Juan; Zuo, Lujie

2015-02-01

To analyze the distribution and drug susceptibility of the pathogenic bacteria in the airway secretions in children with tracheobronchial foreign bodies so as to assist physicians in clinical prescription. Sputum specimens of 1 125 children with tracheobronchial foreign bodies were collected in removal of the foreign bodies by rigid bronchoscope, and the drug susceptibility test was performed. Pathogenic bacteria were detected in 218 (19.4%) of 1 125 sputum specimens. Among the pathogenic bacteria, 126 (57.79%) strains were gram-negative bacilli, consisting of 76 (34.86%) strains of Haemophilus influenzae, 10 (4.59%) strains of Escherichia coli, 7 (3.21%) strains of Sewer enterobacter, 7 (3.21%) strains of Pseudomonas aeruginosa, and 6 (2.75%) strains of Klebsiella bacillus; and 92 (42.21%) strains were gram-positive bacilli, consisting of 80 (36.69%) strains of Streptococcus pneumonia and 10 (4.59%) strains of Escherichia coli. Most of detected gram-negative bacilli were highly sensitive to cefepime, ceftazidine, imipenem and amikacin, no strains were resistant to meropenem and ciprofloxacin. None of the detected gram-positive bacilli were resistant to cefepime, vancomycin, levofloxacin and teicoplanin. The Haemophilus influenzae of gram-negative bacilli and the Streptococcus pneumonia of gram-positive bacilli are the main pathogenic bacteria existing in the airway secretions of children with tracheobronchial foreign bodies. The Haemophilus influenzae were highly sensitive to cephalosporin, imipenem and amikacin, and the Streptococcus pneumonia to cefepime, vancomycin, levofloxacin and teicoplanin.

Use of the probiotic Lactobacillus plantarum 299 to reduce pathogenic bacteria in the oropharynx of intubated patients: a randomised controlled open pilot study

PubMed Central

Klarin, Bengt; Molin, Göran; Jeppsson, Bengt; Larsson, Anders

2008-01-01

Introduction Ventilator-associated pneumonia (VAP) is usually caused by aspiration of pathogenic bacteria from the oropharynx. Oral decontamination with antiseptics, such as chlorhexidine (CHX) or antibiotics, has been used as prophylaxis against this complication. We hypothesised that the probiotic bacteria Lactobacillus plantarum 299 (Lp299) would be as efficient as CHX in reducing the pathogenic bacterial load in the oropharynx of tracheally intubated, mechanically ventilated, critically ill patients. Methods Fifty critically ill patients on mechanical ventilation were randomised to either oral mechanical cleansing followed by washing with 0.1% CHX solution or to the same cleansing procedure followed by oral application of an emulsion of Lp299. Samples for microbiological analyses were taken from the oropharynx and trachea at inclusion and at defined intervals thereafter. Results Potentially pathogenic bacteria that were not present at inclusion were identified in oropharyngeal samples from eight of the patients treated with Lp299 and 13 of those treated with CHX (p = 0.13). Analysis of tracheal samples yielded similar results. Lp299 was recovered from the oropharynx of all patients in the Lp299 group. Conclusions In this pilot study, we found no difference between the effect of Lp299 and CHX used in oral care procedures, when we examined the effects of those agents on colonisation of potentially pathogenic bacteria in the oropharynx of intubated, mechanically ventilated patients. PMID:18990201

Transmutation of Personal Glucose Meters into Portable and Highly Sensitive Microbial Pathogen Detection Platform.

PubMed

Wang, Zhenzhen; Chen, Zhaowei; Gao, Nan; Ren, Jinsong; Qu, Xiaogang

2015-10-07

Herein, for the first time, we presented a simple and general approach by using personal glucose meters (PGM) for portable and ultrasensitive detection of microbial pathogens. Upon addition of pathogenic bacteria, glucoamylase-quaternized magnetic nanoparticles (GA-QMNPS) conjugates were disrupted by the competitive multivalent interactions between bacteria and QMNPS, resulting in the release of GA. After magnetic separation, the free GA could catalyze the hydrolysis of amylose into glucose for quantitative readout by PGM. In such way, PGM was transmuted into a bacterial detection device and extremely low detection limits down to 20 cells mL(-1) was achieved. More importantly, QMNPS could inhibit the growth of the bacteria and destroy its cellular structure, which enabled bacteria detection and inhibition simultaneously. The simplicity, portability, sensitivity and low cost of presented work make it attractive for clinical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bacteria–bacteria interactions within the microbiota of the ancestral metazoan Hydra contribute to fungal resistance

PubMed Central

Fraune, Sebastian; Anton-Erxleben, Friederike; Augustin, René; Franzenburg, Sören; Knop, Mirjam; Schröder, Katja; Willoweit-Ohl, Doris; Bosch, Thomas CG

2015-01-01

Epithelial surfaces of most animals are colonized by diverse microbial communities. Although it is generally agreed that commensal bacteria can serve beneficial functions, the processes involved are poorly understood. Here we report that in the basal metazoan Hydra, ectodermal epithelial cells are covered with a multilayered glycocalyx that provides a habitat for a distinctive microbial community. Removing this epithelial microbiota results in lethal infection by the filamentous fungus Fusarium sp. Restoring the complex microbiota in gnotobiotic polyps prevents pathogen infection. Although mono-associations with distinct members of the microbiota fail to provide full protection, additive and synergistic interactions of commensal bacteria are contributing to full fungal resistance. Our results highlight the importance of resident microbiota diversity as a protective factor against pathogen infections. Besides revealing insights into the in vivo function of commensal microbes in Hydra, our findings indicate that interactions among commensal bacteria are essential to inhibit pathogen infection. PMID:25514534

Survival of pathogenic bacteria in compost with special reference to Escherichia coli.

PubMed

Gong, Chun-ming; Koichi, Inoue; Shunji, Inanaga; Takashi, Someya

2005-01-01

Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157:H7 (E. Coli O157). We investigated pathogenic bacteria in compost collected from the compost facilities, and evaluated the survival of E. coli K12 and O157 in laboratory experiments. Out of 19 compost product samples, coliform bacteria and salmonella were detected in 7 and 3 samples respectively. The number of coliform bacteria was 1.8 x 10(2) to 2.5 x 10(6) CFU/g dw and that of salmonella was 4.2 x 10(1) to 6.0 x 10(3) CFU/g dw. Moreover, coliform bacteria, fecal coliform, E. coli and salmonella were detected during composting at 54 degrees C to 67 degrees C. The results indicated that moisture content was a very important factor to the heat sensitivity of pathogenic bacteria in compost, E. coil in compost of high moisture content was more sensitive than that in compost of low moisture content, cells harvested in logarithmic phase was more sensitive than these in stationary phase, and E. coli K12 was more sensitive than E. coli O157. Based on the D values, the lethal time of E. coli K12 and O157 from l0(8) to 10(0) CFU/g dw were 16.3 and 28.8 min, respectively, at 60 degrees C in compost with 40% moisture content. However, some E. coil cells survived in composting process at 54 degrees C to 67 degrees C. Water potential (low moisture content) and physiological aspects of bacteria (stationary phase) could explain only in part of the prolonged survival of E. coil in compost, and there should be some other factors that are conducive to bacterial survival in compost.

Multidrug-resistant pathogens in the food supply.

PubMed

Doyle, Marjorie E

2015-04-01

Antimicrobial resistance, including multidrug resistance (MDR), is an increasing problem globally. MDR bacteria are frequently detected in humans and animals from both more- and less-developed countries and pose a serious concern for human health. Infections caused by MDR microbes may increase morbidity and mortality and require use of expensive drugs and prolonged hospitalization. Humans may be exposed to MDR pathogens through exposure to environments at health-care facilities and farms, livestock and companion animals, human food, and exposure to other individuals carrying MDR microbes. The Centers for Disease Control and Prevention classifies drug-resistant foodborne bacteria, including Campylobacter, Salmonella Typhi, nontyphoidal salmonellae, and Shigella, as serious threats. MDR bacteria have been detected in both meat and fresh produce. Salmonellae carrying genes coding for resistance to multiple antibiotics have caused numerous foodborne MDR outbreaks. While there is some level of resistance to antimicrobials in environmental bacteria, the widespread use of antibiotics in medicine and agriculture has driven the selection of a great variety of microbes with resistance to multiple antimicrobials. MDR bacteria on meat may have originated in veterinary health-care settings or on farms where animals are given antibiotics in feed or to treat infections. Fresh produce may be contaminated by irrigation or wash water containing MDR bacteria. Livestock, fruits, and vegetables may also be contaminated by food handlers, farmers, and animal caretakers who carry MDR bacteria. All potential sources of MDR bacteria should be considered and strategies devised to reduce their presence in foods. Surveillance studies have documented increasing trends in MDR in many pathogens, although there are a few reports of the decline of certain multidrug pathogens. Better coordination of surveillance programs and strategies for controlling use of antimicrobials need to be implemented in both human and animal medicine and agriculture and in countries around the world.

Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria

PubMed Central

Lambrecht, Ellen; Baré, Julie; Chavatte, Natascha; Bert, Wim; Sabbe, Koen

2015-01-01

The production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, and Listeria monocytogenes) survive inside cysts of the ubiquitous amoeba Acanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, with Salmonella enterica surviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed. PMID:26070667

The proportional lack of archaeal pathogens: Do viruses/phages hold the key?

PubMed Central

Gill, Erin E; Brinkman, Fiona S L

2011-01-01

Although Archaea inhabit the human body and possess some characteristics of pathogens, there is a notable lack of pathogenic archaeal species identified to date. We hypothesize that the scarcity of disease-causing Archaea is due, in part, to mutually-exclusive phage and virus populations infecting Bacteria and Archaea, coupled with an association of bacterial virulence factors with phages or mobile elements. The ability of bacterial phages to infect Bacteria and then use them as a vehicle to infect eukaryotes may be difficult for archaeal viruses to evolve independently. Differences in extracellular structures between Bacteria and Archaea would make adsorption of bacterial phage particles onto Archaea (i.e. horizontal transfer of virulence) exceedingly hard. If phage and virus populations are indeed exclusive to their respective host Domains, this has important implications for both the evolution of pathogens and approaches to infectious disease control. PMID:21328413

Centrifugal sedimentation immunoassays for multiplexed detection of enteric bacteria in ground water

DOE PAGES

Litvinov, Julia; Moen, Scott T.; Koh, Chung-Yan; ...

2016-01-01

Water-born pathogens pose significant threat to the global population and early detection plays an important role both in making drinking water safe, as well as in diagnostics and treatment of water-borne diseases. We present an innovative centrifugal microfluidic platform (SpinDx) for detection of bacterial pathogens using bead-based immunoassays. Our approach is based on binding of pathogens to antibody-functionalized capture particles followed by sedimentation of the particles through a density-media in a microfluidic disk and quantification by fluorescence microscopy. Our platform is fast (20 min), sensitive (10 3 CFU/mL), requires minimal sample preparation, and can detect multiple pathogens simultaneously with sensitivitymore » similar to that required by the EPA. We demonstrate detection of a panel of enteric bacteria (Escherichia coli, Salmonella typhimurium, Shigella, Listeria, and Campylobacter) at concentrations as low as 10 3 CFU/mL or 30 bacteria per reaction.« less

Centrifugal sedimentation immunoassays for multiplexed detection of enteric bacteria in ground water

PubMed Central

Litvinov, Julia; Moen, Scott T.; Koh, Chung-Yan; Singh, Anup K.

2016-01-01

Waterborne pathogens pose significant threat to the global population and early detection plays an important role both in making drinking water safe, as well as in diagnostics and treatment of water-borne diseases. We present an innovative centrifugal sedimentation immunoassay platform for detection of bacterial pathogens in water. Our approach is based on binding of pathogens to antibody-functionalized capture particles followed by sedimentation of the particles through a density-media in a microfluidic disk. Beads at the distal end of the disk are imaged to quantify the fluorescence and determine the bacterial concentration. Our platform is fast (20 min), can detect as few as ∼10 bacteria with minimal sample preparation, and can detect multiple pathogens simultaneously. The platform was used to detect a panel of enteric bacteria (Escherichia coli, Salmonella typhimurium, Shigella, Listeria, and Campylobacter) spiked in tap and ground water samples. PMID:26858815

Molecular Determinants in Phagocyte-Bacteria Interactions.

PubMed

Kaufmann, Stefan H E; Dorhoi, Anca

2016-03-15

Phagocytes are crucial for host defense against bacterial pathogens. As first demonstrated by Metchnikoff, neutrophils and mononuclear phagocytes share the capacity to engulf, kill, and digest microbial invaders. Generally, neutrophils focus on extracellular, and mononuclear phagocytes on intracellular, pathogens. Reciprocally, extracellular pathogens often capitalize on hindering phagocytosis and killing of phagocytes, whereas intracellular bacteria frequently allow their engulfment and then block intracellular killing. As foreseen by Metchnikoff, phagocytes become highly versatile by acquiring diverse phenotypes, but still retaining some plasticity. Further, phagocytes engage in active crosstalk with parenchymal and immune cells to promote adjunctive reactions, including inflammation, tissue healing, and remodeling. This dynamic network allows the host to cope with different types of microbial invaders. Here we present an update of molecular and cellular mechanisms underlying phagocyte functions in antibacterial defense. We focus on four exemplary bacteria ranging from an opportunistic extracellular to a persistent intracellular pathogen. Copyright © 2016 Elsevier Inc. All rights reserved.