WorldWideScience

Sample records for antibiotic-resistant bacterial pathogens

  1. Bottlenecks in the transmission of antibiotic resistance from natural ecosystems to human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Jose L Martinez

    2012-01-01

    Full Text Available It is generally accepted that resistance genes acquired by human pathogens trough horizontal gene transfer have been originated in environmental, non pathogenic bacteria. As the consequence, there exists an increasing concern on the role that natural, non-clinical ecosystems, may play on the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance upon their expression in a heterologous host is much larger than what is actually found in human pathogens. Along the review, the role that different processes as founder effect, ecological connectivity, fitness costs or second-order selection may have on the establishment of a specific resistance determinant in the population of bacterial pathogens is analysed.

  2. Cultivation and qPCR Detection of Pathogenic and Antibiotic-Resistant Bacterial Establishment in Naive Broiler Houses.

    Science.gov (United States)

    Brooks, J P; McLaughlin, M R; Adeli, A; Miles, D M

    2016-05-01

    Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space for approximately 6.5 wk. This environment is known for harboring pathogens and antibiotic-resistant bacteria, but studies have focused on previously established houses with mature litter microbial populations. In the current study, a set of three naive houses were followed from inception through 11 broiler flocks and monitored for ambient climatic conditions, bacterial pathogens, and antibiotic resistance. Within the first 3 wk of the first flock cycle, 100% of litter samples were positive for and , whereas was cultivation negative but PCR positive. Antibiotic resistance genes were ubiquitously distributed throughout the litter within the first flock, approaching 10 to 10 genomic units g. Preflock litter levels were approximately 10 CFU g for heterotrophic plate count bacteria, whereas midflock levels were >10 colony forming units (CFU) g; other indicators demonstrated similar increases. The influence of intrahouse sample location was minor. In all likelihood, given that preflock levels were negative for pathogens and antibiotic resistance genes and 4 to 5 Log lower than flock levels for indicators, incoming birds most likely provided the colonizing microbiome, although other sources were not ruled out. Most bacterial groups experienced a cyclical pattern of litter contamination seen in other studies, whereas microbial stabilization required approximately four flocks. This study represents a first-of-its-kind view into the time required for bacterial pathogens and antibiotic resistance to colonize and establish in naive broiler houses.

  3. Bottlenecks in the Transferability of Antibiotic Resistance from Natural Ecosystems to Human Bacterial Pathogens

    OpenAIRE

    Martínez, José L.

    2012-01-01

    It is generally accepted that resistance genes acquired by human pathogens through horizontal gene transfer originated in environmental, non-pathogenic bacteria. As a consequence, there is increasing concern on the roles that natural, non-clinical ecosystems, may play in the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance on their expression in a heterologous host is much larger than what is actually found in human...

  4. Antibiotic Resistance Pattern Of Bacterial Pathogens Isolated From Poultry Manure Used To Fertilize Fish Ponds In New Bussa, Nigeria

    Directory of Open Access Journals (Sweden)

    Funso Omojowo

    2013-02-01

    Full Text Available This study was carried out to isolate and identify antibiotic resistant bacteria from poultry manure usually used for pond fertilization. Poultry manure from 120 Chickens in National Institute for Freshwater Fisheries Research (NIFFR integrated fish farms, New-Bussa, Nigeria was collected. Five bacterial pathogens; Salmonella typhi, Escherichia coli, Shigella dysenteriae, Staphylococcus aureus and Aeromonas hydrophila were isolated. Antibiotic susceptibility testing carried out using the disk diffusion technique. Antibiotics used were; ofloxacin, amoxicillin, tetracycline, ampicillin, erythromycin, gentamicin, nalidixic acid and chloramphenicol. All the isolated organisms were 100% sensitive to ofloxacin. The multiple resistance pattern revealed that 100% were resistant to tetracycline, 84.34% resistant to ampicillin, 76.68% resistant to amoxicillin, 66% resistant to chloramphenicol, 66% resistant to gentamicin, 29% resistant to erythromycin, 28.34% resistant to nalidixic acid. The risk posed by untreated poultry manure used in fish pond fertilization and the public health implications of these results were discussed.

  5. In vitro effectiveness of the antimicrobial peptide eCATH1 against antibiotic-resistant bacterial pathogens of horses.

    Science.gov (United States)

    Schlusselhuber, Margot; Guldbech, Kristen; Sevin, Corinne; Leippe, Matthias; Petry, Sandrine; Grötzinger, Joachim; Giguère, Steeve; Cauchard, Julien

    2014-01-01

    The equine antimicrobial peptide eCATH1 previously has been shown to have in vitro activity against antibiotic-susceptible reference strains of Rhodococcus equi and common respiratory bacterial pathogens of foals. Interestingly, eCATH1 was also found to be effective in the treatment of R. equi infection induced in mice. The aim of this study was to assess the in vitro activity of eCATH1 against equine isolates of Gram-negative (Escherichia coli, Salmonella enterica, Klebsiella pneumoniae and Pseudomonas spp.) and Gram-positive (R. equi, Staphylococcus aureus) bacteria resistant to multiple classes of conventional antibiotics. A modified microdilution method was used to evaluate the minimum inhibitory concentrations (MICs) of the antimicrobial peptide. The study revealed that eCATH1 was active against all equine isolates of E. coli, S. enterica, K. pneumoniae, Pseudomonas spp. and R. equi tested, with MICs of 0.5-16 μg mL(-1), but was not active against most isolates of S. aureus. In conclusion, the activity of the equine antimicrobial peptide eCATH1 appears to not be hampered by the antibiotic resistance of clinical isolates. Thus, the data suggest that eCATH1 could be useful, not only in the treatment of R. equi infections, but also of infections caused by multidrug-resistant Gram-negative pathogens.

  6.   Bloodstream Bacterial Pathogens and their Antibiotic Resistance Pattern in Dhahira Region, Oman

    Directory of Open Access Journals (Sweden)

    PP Geethanjali

    2011-07-01

    Full Text Available Objectives: To describe the epidemiological, clinical, microbiological characteristics and antimicrobial resistance pattern of Bloodstream infections in Dhahira region, Oman.Methods: Clinical data was collected from all patients with positive blood cultures for two years period. Standard laboratory methods were used for blood culture. Antibiotic sensitivity was tested using Kirby-Bauer disc diffusion method.Results: Of the 360 bacterial pathogens isolated from 348 patients, 57.8�0were gram-positive and 42.2�0were gram-negative. The common isolates were: Streptococcus species 76 (21.1� coagulase-negative Staphylococci 75 (20.8� Escherichia coli 43 (11.9� Staphylococcus aureus 41 (11.4� Overall, mortality was 21.3�0(74/348. Staphylococcus species (Staphylococcus aureus and CoNS were more commonly resistant to Trimethoprim/ Sulphamethoxazole (35.3�20and Penicillin (25.9� Streptococcus species were resistant to Trimethoprim/Sulphamethoxazole (39.1�20and Erythromycin (19.6�Conclusion: Bloodstream infections are important causes of morbidity and mortality in our patients, especially among chronically ill elderly adult males. Prescription of proven resistant antibiotics to suspected bacteremic patients needs attention in Dhahira region.

  7. Bacterial vaccines and antibiotic resistance

    OpenAIRE

    Henriques-Normark, Birgitta; Normark, Staffan

    2014-01-01

    Spread of antibiotic resistance is mediated by clonal lineages of bacteria that besides being resistant also possess other properties promoting their success. Some vaccines already in use, such as the pneumococcal conjugate vaccines, have had an effect on these successful clones, but at the same time have allowed for the expansion and resistance evolution of previously minor clones not covered by the vaccine. Since resistance frequently is horizontally transferred it will be difficult to gene...

  8. Resurrecting the intestinal microbiota to combat antibiotic-resistant pathogens.

    Science.gov (United States)

    Pamer, Eric G

    2016-04-29

    The intestinal microbiota, which is composed of diverse populations of commensal bacterial species, provides resistance against colonization and invasion by pathogens. Antibiotic treatment can damage the intestinal microbiota and, paradoxically, increase susceptibility to infections. Reestablishing microbiota-mediated colonization resistance after antibiotic treatment could markedly reduce infections, particularly those caused by antibiotic-resistant bacteria. Ongoing studies are identifying commensal bacterial species that can be developed into next-generation probiotics to reestablish or enhance colonization resistance. These live medicines are at various stages of discovery, testing, and production and are being subjected to existing regulatory gauntlets for eventual introduction into clinical practice. The development of next-generation probiotics to reestablish colonization resistance and eliminate potential pathogens from the gut is warranted and will reduce health care-associated infections caused by highly antibiotic-resistant bacteria.

  9. BACTERIOCINS AND BACTERIOPHAGE LYTIC PROTEINS FROM RUSSIAN FEDERATION AND USA COLLABORATIONS TO CONTROL ANTIBIOTIC RESISTANT BACTERIAL PATHOGENS

    Science.gov (United States)

    Antibiotic resistant bacteria are becoming a problem for agricultural and human medical use worldwide. Consequently, novel antimicrobials were isolated and characterized in collaborative research between PMSRU, ARS-USDA scientists and representatives of the State Research Center for Applied Microbi...

  10. Detection of blaSHV, blaTEM and blaCTX-M antibiotic resistance genes in randomly selected bacterial pathogens from the Steve Biko Academic Hospital.

    Science.gov (United States)

    Ehlers, Marthie M; Veldsman, Chrisna; Makgotlho, Eddy P; Dove, Michael G; Hoosen, Anwar A; Kock, Marleen M

    2009-08-01

    Extended-spectrum beta-lactamases (ESBLs) are considered to be one of the most important antibiotic resistance mechanisms. This study reported the ESBL-producing genes in 53 randomly selected clinical bacterial isolates from the Steve Biko Academic Hospital. The presence of the bla(SHV), bla(TEM) and bla(CTX-M) genes was determined, and the overall prevalence of these genes detected in this study was 87% (46/53) in comparison with the literature; these results were higher when compared with 33% for Escherichia coli in Europe and 0.8% in Denmark for similar pathogens. These research findings indicated that it is crucial to routinely monitor the prevalence of these resistance genes.

  11. Antibiotic resistance among bacterial pathogens in Central Africa: a review of the published literature between 1955 and 2008.

    Science.gov (United States)

    Vlieghe, E; Phoba, M F; Tamfun, J J Muyembe; Jacobs, J

    2009-10-01

    A systematic review of the published literature on bacterial resistance in Central Africa between 1955 and 2008 was performed. Eighty-three publications from seven countries were retrieved, the majority presenting data on enteric and other gram-negative pathogens. Despite methodological limitations in many studies, alarming resistance rates are noted in nearly all pathogens. Of special concern are multidrug resistance in Shigella and Salmonella spp. and the emergence of meticillin-resistant Staphylococcus aureus, high-level penicillin-resistant Streptococcus pneumoniae and extended-spectrum beta-lactamases among gram-negative pathogens. These findings make clear that the Central African region shares the worldwide trend of increasing antimicrobial resistance and is in urgent need of sound surveillance based on competent and affordable microbiology to provide clear data on antimicrobial resistance. These data could enable redaction of local treatment guidelines and fuel national and regional policies to contain antimicrobial resistance.

  12. Persistence of antibiotic resistance in bacterial populations.

    Science.gov (United States)

    Andersson, Dan I; Hughes, Diarmaid

    2011-09-01

    Unfortunately for mankind, it is very likely that the antibiotic resistance problem we have generated during the last 60 years due to the extensive use and misuse of antibiotics is here to stay for the foreseeable future. This view is based on theoretical arguments, mathematical modeling, experiments and clinical interventions, suggesting that even if we could reduce antibiotic use, resistant clones would remain persistent and only slowly (if at all) be outcompeted by their susceptible relatives. In this review, we discuss the multitude of mechanisms and processes that are involved in causing the persistence of chromosomal and plasmid-borne resistance determinants and how we might use them to our advantage to increase the likelihood of reversing the problem. Of particular interest is the recent demonstration that a very low antibiotic concentration can be enriching for resistant bacteria and the implication that antibiotic release into the environment could contribute to the selection for resistance. Several mechanisms are contributing to the stability of antibiotic resistance in bacterial populations and even if antibiotic use is reduced it is likely that most resistance mechanisms will persist for considerable times.

  13. Effects of antibiotic resistance alleles on bacterial evolutionary responses to viral parasites.

    Science.gov (United States)

    Arias-Sánchez, Flor I; Hall, Alex R

    2016-05-01

    Antibiotic resistance has wide-ranging effects on bacterial phenotypes and evolution. However, the influence of antibiotic resistance on bacterial responses to parasitic viruses remains unclear, despite the ubiquity of such viruses in nature and current interest in therapeutic applications. We experimentally investigated this by exposing various Escherichia coli genotypes, including eight antibiotic-resistant genotypes and a mutator, to different viruses (lytic bacteriophages). Across 960 populations, we measured changes in population density and sensitivity to viruses, and tested whether variation among bacterial genotypes was explained by their relative growth in the absence of parasites, or mutation rate towards phage resistance measured by fluctuation tests for each phage. We found that antibiotic resistance had relatively weak effects on adaptation to phages, although some antibiotic-resistance alleles impeded the evolution of resistance to phages via growth costs. By contrast, a mutator allele, often found in antibiotic-resistant lineages in pathogenic populations, had a relatively large positive effect on phage-resistance evolution and population density under parasitism. This suggests costs of antibiotic resistance may modify the outcome of phage therapy against pathogenic populations previously exposed to antibiotics, but the effects of any co-occurring mutator alleles are likely to be stronger.

  14. Bacterial Multidrug Efflux Pumps: Much More Than Antibiotic Resistance Determinants

    Science.gov (United States)

    Blanco, Paula; Hernando-Amado, Sara; Reales-Calderon, Jose Antonio; Corona, Fernando; Lira, Felipe; Alcalde-Rico, Manuel; Bernardini, Alejandra; Sanchez, Maria Blanca; Martinez, Jose Luis

    2016-01-01

    Bacterial multidrug efflux pumps are antibiotic resistance determinants present in all microorganisms. With few exceptions, they are chromosomally encoded and present a conserved organization both at the genetic and at the protein levels. In addition, most, if not all, strains of a given bacterial species present the same chromosomally-encoded efflux pumps. Altogether this indicates that multidrug efflux pumps are ancient elements encoded in bacterial genomes long before the recent use of antibiotics for human and animal therapy. In this regard, it is worth mentioning that efflux pumps can extrude a wide range of substrates that include, besides antibiotics, heavy metals, organic pollutants, plant-produced compounds, quorum sensing signals or bacterial metabolites, among others. In the current review, we present information on the different functions that multidrug efflux pumps may have for the bacterial behaviour in different habitats as well as on their regulation by specific signals. Since, in addition to their function in non-clinical ecosystems, multidrug efflux pumps contribute to intrinsic, acquired, and phenotypic resistance of bacterial pathogens, the review also presents information on the search for inhibitors of multidrug efflux pumps, which are currently under development, in the aim of increasing the susceptibility of bacterial pathogens to antibiotics. PMID:27681908

  15. ANTIBIOTIC RESISTANCE IN THE OPPORTUNISTIC PATHOGEN STENOTROPHOMONAS MALTOPHILIA

    Directory of Open Access Journals (Sweden)

    María Blanca Sánchez

    2015-06-01

    Full Text Available Stenotrophomonas maltophilia is an environmental bacterium found in the soil, associated with plants and animals, and in aquatic environments. It is also an opportunistic pathogen now causing an increasing number of nosocomial infections. The treatment of S. maltophilia is quite difficult given its intrinsic resistance to a number of antibiotics, and because it is able to acquire new resistances via horizontal gene transfer and mutations. Certainly, strains resistant to quinolones, cotrimoxale and/or cephalosporins - antibiotics commonly used to treat S. maltophilia infections - have emerged. The increasing number of available S. maltophilia genomes has allowed the identification and annotation of a large number of antimicrobial and heavy metal resistance genes. Most encode inactivating enzymes and efflux pumps, but information on their role in intrinsic and acquired resistance is limited. Non-typical antibiotic resistance mechanisms that also form part of the intrinsic resistome have been identified via mutant library screening. These include non-typical antibiotic resistance genes, such as bacterial metabolism genes, and non-inheritable resistant phenotypes, such as biofilm formation and persistence. Their relationships with resistance are complex and require further study.

  16. Exposure to phages has little impact on the evolution of bacterial antibiotic resistance on drug concentration gradients

    OpenAIRE

    Zhang, Quan-Guo

    2014-01-01

    The use of phages for treating bacterial pathogens has recently been advocated as an alternative to antibiotic therapy. Here, we test a hypothesis that bacteria treated with phages may show more limited evolution of antibiotic resistance as the fitness costs of resistance to phages may add to those of antibiotic resistance, further reducing the growth performance of antibiotic-resistant bacteria. We did this by studying the evolution of phage-exposed and phage-free Pseudomonas fluorescens cul...

  17. Proteome studies of bacterial antibiotic resistance mechanisms.

    Science.gov (United States)

    Vranakis, Iosif; Goniotakis, Ioannis; Psaroulaki, Anna; Sandalakis, Vassilios; Tselentis, Yannis; Gevaert, Kris; Tsiotis, Georgios

    2014-01-31

    Ever since antibiotics were used to help humanity battle infectious diseases, microorganisms straight away fought back. Antibiotic resistance mechanisms indeed provide microbes with possibilities to by-pass and survive the action of antibiotic drugs. Several methods have been employed to identify these microbial resistance mechanisms in an ongoing effort to reduce the steadily increasing number of treatment failures due to multi-drug-resistant microbes. Proteomics has evolved to an important tool for this area of research. Following rapid advances in whole genome sequencing, proteomic technologies have been widely used to investigate microbial gene expression. This review highlights the contribution of proteomics in identifying microbial drug resistance mechanisms. It summarizes different proteomic studies on bacteria resistant to different antibiotic drugs. The review further includes an overview of the methodologies used, as well as lists key proteins identified, thus providing the reader not only a summary of research already done, but also directions for future research. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.

  18. [Effect of Three Typical Disinfection Byproducts on Bacterial Antibiotic Resistance].

    Science.gov (United States)

    Lü, Lu; Zhang, Meng-lu; Wang, Chun-ming; Lin, Hui-rong; Yu, Xin

    2015-07-01

    The effect of typical disinfection byproducts (DBPs) on bacterial antibiotic resistance was investigated in this study. chlorodibromomethane (CDBM), iodoacetic acid (IAA) and chloral hydrate (CH) were selected, which belong to trihalomethanes (THMs), haloacetic acids (HAAs) and aldehydes, respectively. After exposure to the selected DBPs, the resistance change of the tested strains to antibiotics was determined. As a result, all of the three DBPs induced Pseudomonas aeruginosa PAO1 to gain increased resistance to the five antibiotics tested, and the DBPs ranked as IAA > CH > CDBM according to their enhancement effects. Multidrug resistance could also be enhanced by treatment with IAA. The same result was observed in Escherichia coli K12, suggesting that the effect of DBPs on antibiotic resistance was a common phenomenon. The mechanism was probably that DBPs stimulated oxidative stress, which induced mutagenesis. And the antibiotic resistance mutation frequency could be increased along with mutagenesis. This study revealed that the acquisition of bacterial antibiotic resistance might be related to DBPs in drinking water systems. Besides the genotoxicological risks, the epidemiological risks of DBPs should not be overlooked.

  19. Limits to compensatory adaptation and the persistence of antibiotic resistance in pathogenic bacteria

    OpenAIRE

    MacLean, R. Craig; Vogwill, Tom

    2014-01-01

    Antibiotic resistance carries a fitness cost that could potentially limit the spread of resistance in bacterial pathogens. In spite of this cost, a large number of experimental evolution studies have found that resistance is stably maintained in the absence of antibiotics as a result of compensatory evolution. Clinical studies, on the other hand, have found that resistance in pathogen populations usually declines after antibiotic use is stopped, suggesting that compensatory adaptation is not ...

  20. Bacterial Enzymes and Antibiotic Resistance- Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-25

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β-lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes.

  1. Analysis of the distribution of pathogens and antibiotic resistance in patients with bacterial peritonitis%细菌性腹膜炎病原菌分布及其耐药性分析

    Institute of Scientific and Technical Information of China (English)

    于宏波; 宋阳; 侯晓杰

    2013-01-01

    Objective To analysis of the distribution of pathogens and antibiotic resistance in pantients with bacterial peritonitis. Methods 113 bacterial strains isolated from ascites of patients with bacterial peritonitis were identified and performed antimicrobial susceptibility by phoenixCM 100. Results Among the 113 bacterial strains,the percentage of Gram-negative baeill, Gram-positive cocci and fungi were 56. 6%, 39. 9% and 3. 5% respectively. The most common bacteria were Escherichia coil (23. 0%) and coagulase-negativc staphylococcus (15. 9%). 53. 8% of Escherichia coil and 36. 4% of klebsiclla pneumoniac produced extended-spectrum β-lactamascs; 88. 9% of coagulasc-ncgativc staphylococcus and 57. 1 % of staphylococcus aureus were methicillin-rcsistant. There were the high antibiotic resistance rates and multi-resistant in pathogens of patients with bacterial peritonitis. Conclusion The antibiotic resistance of pathogens in patients with bacterial peritonitis was serious. We should monitor timely changes and development trend of antibiotic resistance of bacteria in order to guide clinical medication.%目的 分析细菌性腹膜炎病原菌分布及耐药状况.方法 用phoenixTM100细菌鉴定及药敏分析仪对113株腹膜炎患者腹水中分离的病原菌进行菌株鉴定和药敏试验.结果 在分离的113株细菌中,革兰阴性杆菌、革兰阳性球菌及真菌分别占56.6%、39.9%和3.5%;革兰阴性菌中以大肠埃希菌占绝对优势(23.0%),革兰阳性菌中以凝固酶阴性葡萄球菌占绝对优势(15.9%).产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌和肺炎克雷伯菌分别占该种细菌的53.8%和36.4%;耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)占凝固酶阴性葡萄球菌的88.9%,耐甲氧西林金黄色葡萄球菌(MRSA)占金黄色葡萄球菌的57.1%.药敏试验表明细菌性腹膜炎的病原菌表现为较高的耐药率及多重耐药性.结论 细菌性腹膜炎的病原菌耐药性严重,及时监测病原

  2. BACTERIAL CAUSES OF LOWER RESPIRATORY TRACT INFECTIONS IN PATIENTS ATTENDING CENTRAL REFERRAL HOSPITAL, GANGTOK WITH REFERENCE TO ANTIBIOTIC RESISTANCE PATTERN

    OpenAIRE

    Priyanka Paul; Tukaram Prabhu

    2013-01-01

    ABSTRACT: BACKGROUND: There is inadequate information from India on various lower respiratory tract pathogens and their resistance pattern in hospital settings. The present study was undertaken to see the bacteriological profile an d the antibiotic resistance pattern of the isolates causing LRTI from this geographic region. OBJECTIVE: To identify and characterize bacterial pathogens causing community acquired and hospital acquired infections with reference to ant...

  3. Encapsulation of cardamom essential oil in chitosan nano-composites: In-vitro efficacy on antibiotic resistant bacterial pathogens and cytotoxicity studies.

    Directory of Open Access Journals (Sweden)

    Bushra Jamil

    2016-10-01

    Full Text Available Natural antimicrobial agents, particularly essential oils present an excellent alternative to current antibiotics due to their potent and broad-spectrum antimicrobial potential, unique mechanisms of action and low tendency to induce resistance. However their potential as a viable therapeutic alternative is greatly compromised due to their hydrophobic and volatile nature. The objective of the current research was to explore the anti-pathogenic potential of essential oils in a bio-based nano-carrier system. Six different essential oils were tested on multi-drug resistant bacterial pathogens. However, cardamom oil was selected for nano-encapsulation because of most potent anti-microbial activity. Cardamom oil loaded chitosan nano-particles were prepared by ionic gelation method with an encapsulation efficiency of more than 90% and size was estimated to be 50-100 nm. The Zeta potential was more than +50 mV that indicate a stable nano-dispersion. Cytotoxicity analysis indicated non haemolytic and non-cytotoxic behaviour on Human Corneal Epithelial Cells and HepG2 cell lines. Cardamom oil loaded chitosan nano-particles were found to exhibit excellent anti-microbial potential against extended spectrum β lactamase producing Escherichia coli and methicillin resistant Staphylococcus aureus. Our results suggested safety and efficacy of cardamom oil loaded chitosan nano-particles for treating multi drug resistant pathogens hence offer an effective alternative to current antibiotic therapy.

  4. Antibiotic resistance in prevalent bacterial and protozoan sexually transmitted infections

    Directory of Open Access Journals (Sweden)

    Karl Krupp

    2015-01-01

    Full Text Available The emergence of multi-drug resistant sexually transmitted infections (STIs is causing a treatment crisis across the globe. While cephalosporin-resistant gonorrhea is one of the most pressing issues, extensively antibiotic resistant Chlamydia trachomatis and Mycoplasma hominis are also becoming commonplace. Experts have suggested that the failure of current treatment regimens are "largely inevitable" and have called for entirely new classes of antimicrobial agents. With the exception of several new classes of drugs primarily targeting nosocomial infections, progress has been slow. While pharmaceutical companies continue to introduce new drugs, they are based on decade-old discoveries. While there is disagreement about what constitutes new classes of antibiotics, many experts suggest that the last truly new family of antimicrobials was discovered in 1987. This review summarizes the existing literature on antibiotic resistance in common bacterial and protozoal STIs. It also briefly discusses several of the most promising alternatives to current therapies, and further examines how advances in drug delivery, formulation, concentration, and timing are improving the efficacy of existing treatments. Finally, the paper discusses the current state of pharmaceutical development for multidrug-resistant STI.

  5. Exposure of juvenile Leghorn chickens to lead acetate enhances antibiotic resistance in enteric bacterial flora.

    Science.gov (United States)

    Nisanian, M; Holladay, S D; Karpuzoglu, E; Kerr, R P; Williams, S M; Stabler, L; McArthur, J Vaun; Tuckfield, R Cary; Gogal, R M

    2014-04-01

    Heavy metals have been implicated for their ability to increase antibiotic resistance in bacteria collected from polluted waters, independent of antibiotic exposure. Specific-pathogen-free Leghorn chickens were therefore given Pb acetate in the drinking water to expose the enteric bacteria to Pb and to determine if antibiotic resistance changed in these bacteria. Concentrations of Pb used were 0.0, 0.01, 0.1, 1.0, or 10.0 mM; birds given the highest 2 concentrations showed signs of moribundity and dehydration and were removed from the study. Vent culture samples were collected for bacterial cultures on d 0 before Pb exposure, d 7 and 14, and then birds were euthanized by CO2 gas for necropsy on d 14, at which time intestinal contents were also collected for bacterial cultures. Fecal swabs but not intestinal samples from Pb-exposed birds contained isolates that had significantly elevated antibiotic resistance. Some of the isolates contained bacteria that were resistant to up to 20 antibiotics. These results suggest the need for repeated studies in chickens infected with zoonotic pathogens.

  6. Induction of bacterial antibiotic resistance by mutagenic halogenated nitrogenous disinfection byproducts.

    Science.gov (United States)

    Lv, Lu; Yu, Xin; Xu, Qian; Ye, Chengsong

    2015-10-01

    Halogenated nitrogenous disinfection byproducts (N-DBPs) raise concerns regarding their mutagenicity and carcinogenicity threatening public health. However, environmental consequence of their mutagenicity has received less attention. In this study, the effect of halogenated N-DBPs on bacterial antibiotic resistance (BAR) was investigated. After exposure to bromoacetamide (BAcAm), trichloroacetonitrile (TCAN) or tribromonitromethane (TBNM), the resistance of Pseudomonas aeruginosa PAO1 to both individual and multiple antibiotics (ciprofloxacin, gentamicin, polymyxin B, rifampin, tetracycline, ciprofloxacin + gentamicin and ciprofloxacin + tetracycline) was increased, which was predominantly ascribed to the overexpression of efflux pumps. The mechanism of this effect was demonstrated to be mutagenesis through sequencing and analyzing antibiotic resistance genes. The same induction phenomena also appeared in Escherichia coli, suggesting this effect may be universal to waterborne pathogens. Therefore, more attention should be given to halogenated N-DBPs, as they could increase not only genotoxicological risks but also epidemiological risks of drinking water.

  7. Seasonal variations in bacterial communities and antibiotic-resistant strains associated with green bottle flies (Diptera: Calliphoridae).

    Science.gov (United States)

    Wei, Ting; Ishida, Ryuichi; Miyanaga, Kazuhiko; Tanji, Yasunori

    2014-05-01

    Green bottle flies occur frequently around human environments in Japan. Many species of green bottle flies have been studied with regard to their importance in forensic examinations or clinical therapies, but the bacterial communities associated with this group of flies have not been comprehensively investigated. In this research, 454 pyrosequencing was used to reveal the bacterial communities in green bottle flies collected in different seasons. Meanwhile, the bacteria were screened with selective media and tested for antibiotic susceptibility. Samples collected in three different seasons harbored distinctive bacterial communities. The predominant genera associated with green bottles flies were Staphylococcus in spring, Ignatzschineria in summer, and Vagococcus, Dysgonomonas, and an unclassified Acetobacteraceae in autumn. An upward trend in bacterial community diversity was observed from spring to autumn. Changes in climatic conditions could be the cause of these seasonal variations in fly-associated bacterial communities. The species of isolated antibiotic-resistant bacteria also differed across seasons, but it was difficult to correlate seasonal changes in antibiotic-resistant bacteria with changes in whole communities. A number of multiple-antibiotic-resistant bacteria were isolated, and some of these strains were closely affiliated with pathogens such as Enterococcus faecalis and Enterococcus faecium, which could cause serious threats to public health. Overall, this research provided us with information about the composition and seasonality of bacterial communities in green bottle flies, and highlighted the risks of fly-mediated dissemination of antibiotic-resistant pathogens.

  8. Evolution of antibiotic resistance is linked to any genetic mechanism affecting bacterial duration of carriage

    Science.gov (United States)

    Lehtinen, Sonja; Blanquart, François; Croucher, Nicholas J.; Turner, Paul; Lipsitch, Marc; Fraser, Christophe

    2017-01-01

    Understanding how changes in antibiotic consumption affect the prevalence of antibiotic resistance in bacterial pathogens is important for public health. In a number of bacterial species, including Streptococcus pneumoniae, the prevalence of resistance has remained relatively stable despite prolonged selection pressure from antibiotics. The evolutionary processes allowing the robust coexistence of antibiotic sensitive and resistant strains are not fully understood. While allelic diversity can be maintained at a locus by direct balancing selection, there is no evidence for such selection acting in the case of resistance. In this work, we propose a mechanism for maintaining coexistence at the resistance locus: linkage to a second locus that is under balancing selection and that modulates the fitness effect of resistance. We show that duration of carriage plays such a role, with long duration of carriage increasing the fitness advantage gained from resistance. We therefore predict that resistance will be more common in strains with a long duration of carriage and that mechanisms maintaining diversity in duration of carriage will also maintain diversity in antibiotic resistance. We test these predictions in S. pneumoniae and find that the duration of carriage of a serotype is indeed positively correlated with the prevalence of resistance in that serotype. These findings suggest heterogeneity in duration of carriage is a partial explanation for the coexistence of sensitive and resistant strains and that factors determining bacterial duration of carriage will also affect the prevalence of resistance. PMID:28096340

  9. The causes and consequences of antibiotic resistance evolution in microbial pathogens

    DEFF Research Database (Denmark)

    Jochumsen, Nicholas

    activity against bacteria resistant to conventional antibiotics and because resistance evolution is expected to be unlikely since the peptides have complex modes of action due to their interaction with the bacterial membrane. The work presented in this thesis has involved studies to increase our...... patients; and 3) most CF-associated P. aeruginosa infections are clonal, which means that evolution of antibiotic resistance in P. aeruginosa infections in individual patients probably occurs de novo. The first study presented in this thesis investigated the regulation of CAMP tolerance in P. aeruginosa......The evolution of antimicrobial resistance in bacterial pathogens is a growing global health problem that is gradually making the successful treatment of infectious diseases more difficult. Antimicrobial peptides have been proposed as promising candidates for future drug development as they retain...

  10. Analysis of the distribution and antibiotic resistance of pathogenic bacterial isolates from clinical specimens in intensive care unit%重症监护病房临床分离病原菌分布及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    邱海艳; 赵文静

    2011-01-01

    Objective To acquire the timely knowledge and dynamic information of the distribution of pathogenic bacteria and their trend in antibiotic resistance in intensive care unit ( ICU ), and provide clinical guidance on rational use of antibiotics. Methods A retrospective analysis was conducted on the distribution of bacterial flora and drug resistance of microbial isolates from 2007 to 2009 in our ICU. Results A total of 705 strains of pathogenic bacteria were isolated: Gram - negative bacilli were 57.16 %; Gram - positive cocci accounted for 30.21% and fungi comprised 12.62 % of the bacteria. Non - zymophytes were multidrug resistant. Conclusion Acinetobacter baumannii and Pseudomonas aeruginosa are the most frequent pathogenic bacteria and are strongly resistant to common antibiotics. Drug resistance surveillance should be emphasized and rational use of antibiotics is of great importance to the effective control of infections in ICU.%目的 及时了解和动态掌握重症监护病房(ICU)病原菌分布及耐药趋势,指导临床合理使用抗菌药物.方法 对我院ICU 2007年-2009年所分离的病原菌的菌群分布及耐药性进行回顾性分析.结果 共分离出病原菌705株.其中革兰阴性菌占57.16%;革兰阳性菌占30.21%,真菌占12.62%.鲍曼不动杆菌和铜绿假单胞菌呈多重耐药.结论 非发酵菌已成为ICU感染的最常见病原菌,对常用抗生素耐药严重,应加强耐药监测,合理使用抗生素对有效控制ICU感染十分重要.

  11. Prevalence and Antibiotic Resistance of Neonatal Sepsis Pathogens in Neyshabour, Iran

    Directory of Open Access Journals (Sweden)

    Behmadi

    2016-04-01

    Full Text Available Background Neonatal sepsis is a systemic inflammatory response syndrome that is secondary to infection. It is a major cause of neonatal mortality in the world, particularly in developing countries. A definitive diagnosis requires the isolation of pathogens from a normally sterile body site, including blood, cerebrospinal fluid and urine. Empirical antibiotic therapy is based on the physician’s knowledge of the anticipated bacterial species and their expected antibiotic susceptibilities. Objectives The aim of this study was to determine the prevalence and evaluate the antimicrobial susceptibility patterns of bacterial infections at a neonatal unit. Patients and Methods This study was conducted at the neonatal intensive care unit and neonatal ward of Hakim hospital, Neyshabour, Iran. Blood, cerebrospinal fluid (CSF and urine specimens were collected before institution of empirical antibiotic therapy. Antibiotic resistance pattern of the isolates was studied by the disc diffusion technique. Results Coagulase-negative staphylococci (CoNS were the most prevalent pathogens isolated from blood specimens in early and late-onset disease. Escherichia coli and Klebsiella were the most causative pathogens in early and late-onset urinary tract infections. They had high resistance to our empirical antibiotic regimens. Prevalence of bacterial meningitis was low in our study. Conclusions Due to the increasing resistance of pathogens to usual empirical antibiotics, it is reasonable to stress upon preventive measures, so that a minimum number of neonates develop sepsis.

  12. Antibiotic resistance amongst healthcare-associated pathogens in China.

    Science.gov (United States)

    Yezli, Saber; Li, Han

    2012-11-01

    The People's Republic of China, commonly known as China, comprises approximately one-fifth of the world's population. Because of the expanding size and density of its population and the frequent interaction of people with animals, China is a hotspot for the emergence and spread of new microbial threats and is a major contributor to the worldwide infectious disease burden. In recent years, the emergence and rapid spread of severe acute respiratory syndrome (SARS) generated considerable interest in the Chinese healthcare system and its infection control and prevention measures. This review examines antibiotic misuse and the status of antibiotic resistance in the Chinese healthcare system. China has high rates of antibiotic resistance driven by misuse of these agents in a healthcare system that provides strong incentives for overprescribing and in a country where self-medication is common. Tuberculosis remains a serious problem in China, with a high prevalence of multidrug-resistant and extensively drug-resistant strains. Drug resistance amongst nosocomial bacteria has been on a rapid upward trend with a strong inclination towards multidrug resistance. There is a need for effective infection prevention and control measures and strict use of antibiotics in China to control the rise and spread of antibiotic resistance in the country.

  13. Metagenomic analysis of bacterial community composition and antibiotic resistance genes in a wastewater treatment plant and its receiving surface water.

    Science.gov (United States)

    Tang, Junying; Bu, Yuanqing; Zhang, Xu-Xiang; Huang, Kailong; He, Xiwei; Ye, Lin; Shan, Zhengjun; Ren, Hongqiang

    2016-10-01

    The presence of pathogenic bacteria and the dissemination of antibiotic resistance genes (ARGs) may pose big risks to the rivers that receive the effluent from municipal wastewater treatment plants (WWTPs). In this study, we investigated the changes of bacterial community and ARGs along treatment processes of one WWTP, and examined the effects of the effluent discharge on the bacterial community and ARGs in the receiving river. Pyrosequencing was applied to reveal bacterial community composition including potential bacterial pathogen, and Illumina high-throughput sequencing was used for profiling ARGs. The results showed that the WWTP had good removal efficiency on potential pathogenic bacteria (especially Arcobacter butzleri) and ARGs. Moreover, the bacterial communities of downstream and upstream of the river showed no significant difference. However, the increase in the abundance of potential pathogens and ARGs at effluent outfall was observed, indicating that WWTP effluent might contribute to the dissemination of potential pathogenic bacteria and ARGs in the receiving river.

  14. New antimicrobial contact catalyst killing antibiotic resistant clinical and waterborne pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Guridi, A. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Diederich, A.-K. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Aguila-Arcos, S.; Garcia-Moreno, M. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Blasi, R.; Broszat, M. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Schmieder, W.; Clauss-Lendzian, E. [Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Sakinc-Gueler, T. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Andrade, R. [Advanced Research Facilities (SGIker), University of the Basque Country, UPV/EHU, 48940 Leioa (Spain); Alkorta, I. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Meyer, C.; Landau, U. [Largentec GmbH, Am Waldhaus 32, 14129 Berlin (Germany); Grohmann, E., E-mail: elisabeth.grohmann@googlemail.com [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany)

    2015-05-01

    Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited the growth of the nosocomial pathogens Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by the growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced the growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, which is independent of the release of silver ions. Thus, the novel antimicrobial coating could represent an alternative to combat microbial growth avoiding the toxic side effects of high levels of silver ions on eukaryotic cells. - Highlights: • The novel antimicrobial inhibits growth of clinical staphylococci and enterococci. • The novel antimicrobial inhibits growth of Legionella in drinking water. • A putative mode of action of the antimicrobial coating is presented.

  15. Increase in Antibiotic-Resistant Gram-Negative Bacterial Infections in Febrile Neutropenic Children

    OpenAIRE

    Lee, Joon Hee; Kim, Seul-Ki; Kim, Seong Koo; Han, Seung Beom; Lee, Jae Wook; Lee, Dong-Gun; Chung, Nack-Gyun; Cho, Bin; Jeong, Dae Chul; Kang, Jin Han; Kim, Hack-Ki

    2016-01-01

    Background The incidence of bacteremia caused by Gram-negative bacteria has increased recently in febrile neutropenic patients with the increase of antibiotic-resistant Gram-negative bacterial infections. This study aimed to identify the distribution of causative bacteria and the proportion of antibiotic-resistant bacteria in bacteremia diagnosed in febrile neutropenic children. Materials and Methods The medical records of febrile neutropenic children diagnosed with bacteremia between 2010 an...

  16. The drinking water treatment process as a potential source of affecting the bacterial antibiotic resistance.

    Science.gov (United States)

    Bai, Xiaohui; Ma, Xiaolin; Xu, Fengming; Li, Jing; Zhang, Hang; Xiao, Xiang

    2015-11-15

    Two waterworks, with source water derived from the Huangpu or Yangtze River in Shanghai, were investigated, and the effluents were plate-screened for antibiotic-resistant bacteria (ARB) using five antibiotics: ampicillin (AMP), kanamycin (KAN), rifampicin (RFP), chloramphenicol (CM) and streptomycin (STR). The influence of water treatment procedures on the bacterial antibiotic resistance rate and the changes that bacteria underwent when exposed to the five antibiotics at concentration levels ranging from 1 to 100 μg/mL were studied. Multi-drug resistance was also analyzed using drug sensitivity tests. The results indicated that bacteria derived from water treatment plant effluent that used the Huangpu River rather than the Yangtze River as source water exhibited higher antibiotic resistance rates against AMP, STR, RFP and CM but lower antibiotic resistance rates against KAN. When the antibiotic concentration levels ranged from 1 to 10 μg/mL, the antibiotic resistance rates of the bacteria in the water increased as water treatment progressed. Biological activated carbon (BAC) filtration played a key role in increasing the antibiotic resistance rate of bacteria. Chloramine disinfection can enhance antibiotic resistance. Among the isolated ARB, 75% were resistant to multiple antibiotics. Ozone oxidation, BAC filtration and chloramine disinfection can greatly affect the relative abundance of bacteria in the community.

  17. Renew or die: The molecular mechanisms of peptidoglycan recycling and antibiotic resistance in Gram-negative pathogens.

    Science.gov (United States)

    Domínguez-Gil, Teresa; Molina, Rafael; Alcorlo, Martín; Hermoso, Juan A

    2016-09-01

    Antimicrobial resistance is one of the most serious health threats. Cell-wall remodeling processes are tightly regulated to warrant bacterial survival and in some cases are directly linked to antibiotic resistance. Remodeling produces cell-wall fragments that are recycled but can also act as messengers for bacterial communication, as effector molecules in immune response and as signaling molecules triggering antibiotic resistance. This review is intended to provide state-of-the-art information about the molecular mechanisms governing this process and gather structural information of the different macromolecular machineries involved in peptidoglycan recycling in Gram-negative bacteria. The growing body of literature on the 3D structures of the corresponding macromolecules reveals an extraordinary complexity. Considering the increasing incidence and widespread emergence of Gram-negative multidrug-resistant pathogens in clinics, structural information on the main actors of the recycling process paves the way for designing novel antibiotics disrupting cellular communication in the recycling-resistance pathway.

  18. Antibiotics, Antibiotic Resistance Genes, and Bacterial Community Composition in Fresh Water Aquaculture Environment in China.

    Science.gov (United States)

    Xiong, Wenguang; Sun, Yongxue; Zhang, Tong; Ding, Xueyao; Li, Yafei; Wang, Mianzhi; Zeng, Zhenling

    2015-08-01

    Environmental antibiotic resistance has drawn increasing attention due to its great threat to human health. In this study, we investigated concentrations of antibiotics (tetracyclines, sulfonamides and (fluoro)quinolones) and abundances of antibiotic resistance genes (ARGs), including tetracycline resistance genes, sulfonamide resistance genes, and plasmid-mediated quinolone resistance genes, and analyzed bacterial community composition in aquaculture environment in Guangdong, China. The concentrations of sulfametoxydiazine, sulfamethazine, sulfamethoxazole, oxytetracycline, chlorotetracycline, doxycycline, ciprofloxacin, norfloxacin, and enrofloxacin were as high as 446 μg kg(-1) and 98.6 ng L(-1) in sediment and water samples, respectively. The relative abundances (ARG copies/16S ribosomal RNA (rRNA) gene copies) of ARGs (sul1, sul2, sul3, tetM, tetO, tetW, tetS, tetQ, tetX, tetB/P, qepA, oqxA, oqxB, aac(6')-Ib, and qnrS) were as high as 2.8 × 10(-2). The dominant phyla were Proteobacteria, Bacteroidetes, and Firmicutes in sediment samples and Proteobacteria, Actinobacteria and Bacteroidetes in water samples. The genera associated with pathogens were also observed, such as Acinetobacter, Arcobacter, and Clostridium. This study comprehensively investigated antibiotics, ARGs, and bacterial community composition in aquaculture environment in China. The results indicated that fish ponds are reservoirs of ARGs and the presence of potential resistant and pathogen-associated taxonomic groups in fish ponds might imply the potential risk to human health.

  19. Antibiotic Resistance in Human Chronic Periodontitis Microbiota

    NARCIS (Netherlands)

    Rams, Thomas E.; Degener, John E.; van Winkelhoff, Arie J.

    2014-01-01

    Background: Patients with chronic periodontitis (CP) may yield multiple species of putative periodontal bacterial pathogens that vary in their antibiotic drug susceptibility. This study determines the occurrence of in vitro antibiotic resistance among selected subgingival periodontal pathogens in pa

  20. Bacteriophage therapy for membrane biofouling in membrane bioreactors and antibiotic-resistant bacterial biofilms.

    Science.gov (United States)

    Bhattacharjee, Ananda Shankar; Choi, Jeongdong; Motlagh, Amir Mohaghegh; Mukherji, Sachiyo T; Goel, Ramesh

    2015-08-01

    To demonstrate elimination of bacterial biofilm on membranes to represent wastewater treatment as well as biofilm formed by antibiotic-resistant bacterial (ARB) to signify medical application, an antibiotic-resistant bacterium and its lytic bacteriophage were isolated from a full-scale wastewater treatment plant. Based on gram staining and complete 16 S rDNA sequencing, the isolated bacterium showed a more than 99% homology with Delftia tsuruhatensis, a gram-negative bacterium belonging to β-proteobacteria. The Delftia lytic phage's draft genome revealed the phage to be an N4-like phage with 59.7% G + C content. No transfer RNAs were detected for the phage suggesting that the phage is highly adapted to its host Delftia tsuruhatensis ARB-1 with regard to codon usage, and does not require additional tRNAs of its own. The gene annotation of the Delftia lytic phage found three different components of RNA polymerase (RNAP) in the genome, which is a typical characteristic of N4-like phages. The lytic phage specific to D. tsuruhatensis ARB-1 could successfully remove the biofilm formed by it on a glass slide. The water flux through the membrane of a prototype lab-scale membrane bioreactor decreased from 47 L/h m(2) to ∼15 L/h m(2) over 4 days due to a biofilm formed by D. tsuruhatensis ARB-1. However, the flux increased to 70% of the original after the lytic phage application. Overall, this research demonstrated phage therapy's great potential to solve the problem of membrane biofouling, as well as the problems posed by pathogenic biofilms in external wounds and on medical instruments.

  1. Longitudinal Comparison of Antibiotic Resistance in Diarrheagenic and Non-pathogenic Escherichia coli from Young Tanzanian Children

    Science.gov (United States)

    Seidman, Jessica C.; Johnson, Lashaunda B.; Levens, Joshua; Mkocha, Harran; Muñoz, Beatriz; Silbergeld, Ellen K.; West, Sheila K.; Coles, Christian L.

    2016-01-01

    Enteroaggregative, enteropathogenic, and enterotoxigenic Escherichia coli contribute significantly to the burden of diarrheal infections particularly in developing countries. Antibiotic resistance is increasingly common among bacterial pathogens including pathogenic E. coli. We assessed the relationship between pathogenic E. coli carriage and resistance to six antibiotics in E. coli isolated from young children in rural Tanzania. We surveyed temporal stability in antibiotic resistance in 2492 E. coli isolated from fecal samples obtained from young children in rural Tanzania collected over a 6 months period. Approximately half of the 377 children sampled were exposed to an azithromycin mass treatment program for trachoma control and half resided in control villages. Children were sampled at baseline, 1-, 3-, and 6 months following azithromycin treatment. We compared resistance to six antibiotics in pathogenic and non-pathogenic strains at the population level, within fecal specimens, and within individuals over time using chi-square tests, paired odds ratios, and logistic regression, respectively. Resistance to ampicillin and trimethoprim/sulfamethoxazole was highly prevalent (>65%). Resistance to 5 of 6 antibiotics tested and multi-drug resistance occurred more frequently in pathogenic isolates (p ≤ 0.001) within fecal specimens and overall. Azithromycin mass treatment exposure was significantly associated with increased odds of carriage of isolates resistant to erythromycin (OR 3.64, p < 0.001) and trimethoprim/sulfamethoxazole (OR 1.60, p < 0.05). Pathogenic isolates were approximately twice as likely to be resistant to erythromycin, ampicillin, or trimethoprim/sulfamethoxazole compared to non-pathogenic isolates from the same fecal specimen. The potential linkage between resistance and virulence in E. coli suggests hygiene and sanitation interventions aimed at reducing disease burden could play a role in controlling transmission of antibiotic resistance. PMID

  2. Effect of different biochars on antibiotic resistance genes and bacterial community during chicken manure composting.

    Science.gov (United States)

    Cui, Erping; Wu, Ying; Zuo, Yiru; Chen, Hong

    2016-03-01

    Rice straw biochar (RSB) and mushroom biochar (MB) were added to lab-scale chicken manure composting to evaluate their effects on the behaviors of antibiotic resistance genes (ARGs) and on total and bio-available heavy metals (Cu, Zn and As). The associated bacterial community was characterized by 16SrRNA high-throughput sequencing. The abundance of pathogenic bacteria was also calculated. At the end of the control composting experiment, the average removal rate of ARGs was 0.86 log units and the removal rate of pathogenic bacteria was 57.1%. MB addition resulted in a higher removal rate than that in the control composting experiment. However, RSB addition yielded opposite results, which may be due to the higher abundance of Erysipelotrichaceae, Lactobacillaceae, Family_XI_Incertae_Sedis (belonging to Firmicutes carrying and disseminating ARGs) and pathogenic bacteria carrying ARGs. Furthermore, the correlations between bio-available heavy metals and ARGs were more obvious than those between total heavy metals and ARGs.

  3. Comparative analysis of bacterial community and antibiotic-resistant strains in different developmental stages of the housefly (Musca domestica).

    Science.gov (United States)

    Wei, Ting; Hu, Jun; Miyanaga, Kazuhiko; Tanji, Yasunori

    2013-02-01

    The housefly (Musca domestica) is an important host for a variety of bacteria, including some pathogenic and antibiotic-resistant strains. To further investigate the relationship between the housefly and the bacteria it harbors, it is necessary to understand the fate of microorganisms during the larval metamorphosis. The major bacterial communities in three developmental stages of the housefly (maggot, pupa, and adult fly) were investigated by a culture-independent method, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis of 16S rRNA genes. The bacteria that were identified using DGGE analysis spanned phyla Proteobacteria, Firmicutes, and Bacteroidetes. Changes in the predominant genera were observed during the housefly development. Bacteroides, Koukoulia, and Schineria were detected in maggots, Neisseria in pupae, and Macrococcus, Lactococcus, and Kurthia in adult flies. Antibiotic-resistant bacteria were screened using a selective medium and tested for antibiotic susceptibility. Most resistant isolates from maggots and pupae were classified as Proteus spp., while those from adult flies were much more diverse and spanned 12 genera. Among 20 tested strains across the three stages, 18 were resistant to at least two antibiotics. Overall, we demonstrated that there are changes in the major bacterial communities and antibiotic-resistant strains as the housefly develops.

  4. Bacterial viruses enable their host to acquire antibiotic resistance genes from neighbouring cells

    DEFF Research Database (Denmark)

    Haaber, Jakob; Leisner, Jørgen J; Cohn, Marianne T;

    2016-01-01

    Prophages are quiescent viruses located in the chromosomes of bacteria. In the human pathogen, Staphylococcus aureus, prophages are omnipresent and are believed to be responsible for the spread of some antibiotic resistance genes. Here we demonstrate that release of phages from a subpopulation of S...

  5. Bacterial viruses enable their host to acquire antibiotic resistance genes from neighbouring cells

    DEFF Research Database (Denmark)

    Haaber, Jakob Krause; Leisner, Jørgen; Cohn, Marianne Thorup;

    2016-01-01

    Prophages are quiescent viruses located in the chromosomes of bacteria. In the human pathogen, Staphylococcus aureus, prophages are omnipresent and are believed to be responsible for the spread of some antibiotic resistance genes. Here we demonstrate that release of phages from a subpopulation of...

  6. Antibacterial activity of some medicinal mangroves against antibiotic resistant pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Abeysinghe P

    2010-01-01

    Full Text Available The antibacterial activity of the leaves and bark of mangrove plants, Avicennia marina, A. officinalis, Bruguiera sexangula, Exoecaria agallocha, Lumnitzera racemosa, and Rhizophora apiculata was evaluated against antibiotic resistant pathogenic bacteria, Staphylococcus aureus and Proteus sp. Soxhlet extracts of petroleum ether, ethyl acetate, ethanol and water were prepared and evaluated the antibacterial activity using agar diffusion method. Most of the plant extracts showed promising antibacterial activity against both bacterial species. However, higher antibacterial activity was observed for Staphylococcus aureus than Proteus sp. The highest antibacterial activity was shown by ethyl acetate of mature leaf extracts of E. agallocha for Staphylococcus aureus. All ethyl acetate extracts showed higher inhibition against S. aureus while some extracts of chloroform, ethyl acetate and ethanol gave inhibition against Proteus sp. None of the petroleum ether and aqueous extracts showed inhibition against Proteus sp. All fresh plant materials did also show more antibacterial activity against both bacterial strains than did dried plant extracts. Antibacterial activity of fresh and dried plant materials reduced for both bacterial strains with time after extraction. Since L. racemosa and A. marina gave the best inhibition for bacterial species, they were used for further investigations. Charcoal treated plant extracts of L. racemosa and A. marina were able to inhibit both bacterial strains more than those of untreated plant extracts. Phytochemical screening of mature leaf, bark of L. racemosa and leaf extracts of A. marina has been carried out and revealed that leaf and bark contained alkaloids, steroids, triterpenoids and flavonoids. None of the above extracts indicate the presence of saponins and cardiac glycosides. Separated bands of extracts by TLC analysis showed antibacterial activity against S. aureus.

  7. Bacterial viruses enable their host to acquire antibiotic resistance genes from neighbouring cells

    DEFF Research Database (Denmark)

    Haaber, Jakob Krause; Leisner, Jørgen; Cohn, Marianne Thorup

    2016-01-01

    Prophages are quiescent viruses located in the chromosomes of bacteria. In the human pathogen, Staphylococcus aureus, prophages are omnipresent and are believed to be responsible for the spread of some antibiotic resistance genes. Here we demonstrate that release of phages from a subpopulation of S....... aureus cells enables the intact, prophage-containing population to acquire beneficial genes from competing, phage-susceptible strains present in the same environment. Phage infection kills competitor cells and bits of their DNA are occasionally captured in viral transducing particles. Return...... of such particles to the prophage-containing population can drive the transfer of genes encoding potentially useful traits such as antibiotic resistance. This process, which can be viewed as ‘auto-transduction’, allows S. aureus to efficiently acquire antibiotic resistance both in vitro and in an in vivo virulence...

  8. Antibiotics & Resistance : bacterial multidrug resistance and photoactivatable antibiotics

    NARCIS (Netherlands)

    van der Berg, Jan Pieter

    2014-01-01

    Antibioticaresistentie in bacteriën is een serieus gevaar voor de gezondheidszorg. Bacteriën kunnen op verscheidene manieren de schadelijke effecten van antibiotica omzeilen en een van deze manieren is door de medicijnen uit de cel te pompen. Dit onderzoek bestudeerde de rol van zulke transporteiwit

  9. Effect of Vibration on Bacterial Growth and Antibiotic Resistance

    Science.gov (United States)

    Juergensmeyer, Elizabeth A.; Juergensmeyer, Margaret A.

    2004-01-01

    The purpose of this research grant was to provide a fundamental, systematic investigation of the effects of oscillatory acceleration on bacterial proliferation and their responses to antibiotics in a liquid medium.

  10. The Molecular Ecology of Antibiotic Resistance Genes in Genital Tract Pathogens

    OpenAIRE

    Johnson, Alan P.

    2011-01-01

    Genital tract pathogens resistant to antibiotics are now commonly encountered in many parts of the world. The emergence of such strains may clearly be accounted for, at least in part, by the selection of mutant strains which would have a selective advantage in the face of widespread antibiotic usage. Molecular and genetic analysis of antibioticresistant organisms, however, indicates that such an explanation is an over simplification. In many instances genes coding for antibiotic resistance ap...

  11. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City

    Science.gov (United States)

    Gonsu, Hortense Kamga; Koulla-Shiro, Sinata

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with prescription practices of local physicians. Methods. We performed a cross-sectional descriptive study at two main hospitals in Yaoundé, collecting a clean-catch mid-stream urine sample from 92 patients having a clinical diagnosis of UTI. The empirical antibiotherapy was noted, and identification of bacterial species was done on CLED agar; antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Results. A total of 55 patients had samples positive for a UTI. Ciprofloxacin and amoxicillin/clavulanic acid were the most empirically prescribed antibiotics (30.9% and 23.6%, resp.); bacterial isolates showed high prevalence of resistance to both compounds. Escherichia coli (50.9%) was the most common pathogen, followed by Klebsiella pneumoniae (16.4%). Prevalence of resistance for ciprofloxacin was higher compared to newer quinolones. Conclusions. E. coli and K. pneumoniae were the predominant bacterial etiologies; the prevalence of resistance to commonly prescribed antibiotics was high. PMID:27667998

  12. Multiplex characterization of human pathogens including species and antibiotic-resistance gene identification.

    Science.gov (United States)

    Barisˇ ić, Ivan; Petzka, Josefine; Schoenthaler, Silvia; Vierlinger, Klemens; Noehammer, Christa; Wiesinger-Mayr, Herbert

    2016-01-01

    The efficient medical treatment of infections requires detailed information about the pathogens involved and potential antibiotic-resistance mechanisms. The dramatically increasing incidence of multidrug-resistant bacteria especially highlights the importance of sophisticated diagnostic tests enabling a fast patient-customized therapy. However, the current molecular detection methods are limited to either the detection of species or only a few antibiotic-resistance genes.In this work, we present a human pathogen characterization assay using a rRNA gene microarray identifying 75 species comprising bacteria and fungi. A statistical classifier was developed to facilitate the automated species identification. Additionally, the clinically most important β-lactamases were identified simultaneously in a 100-plex reaction using padlock probes and the same microarray. The specificity and sensitivity of the combined assay was determined using clinical isolates. The detection limit was 10(5) c.f.u. ml(-1), recovering 89 % of the detectable β-lactamase-encoding genes specifically. The total assay time was less than 7 hand the modular character of the antibiotic-resistance detection allows the easy integration of further genetic targets. In summary, we present a fast, highly specific and sensitive multiplex pathogen characterization assay.

  13. The agricultural use of water treatment plant sludge: pathogens and antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Ignacio Nadal Rocamora

    2015-12-01

    Full Text Available The use of water treatment plant sludge to restore degraded soils is customary agricultural practice, but it could be dangerous from the point of view of both health and the environment. A transient increase of either pathogenic or indicator microbial populations, whose persistence in time is variable and attributed to the characteristics of the soil (types of materials in the soil, any amendments (origin and treatments it has undergone or the weather (humidity and temperature mainly, has often been detected in soils treated with this kind of waste. Given their origin, water treatment plant sludges could lead to the transmission of a pathogens and b antibiotic-resistant microorganisms to human beings through the food chain and cause the spreading of antibiotic resistances as a result of their increase and persistence in the soil for variable periods of time. However, Spanish legislation regulating the use of sludges in the farming industry is based on a very restricted microbiological criterion. Thus, we believe better parameters should be established to appropriately inform of the state of health of soils treated with water treatment plant sludge, including aspects which are not presently assessed such as antibiotic resistance.

  14. PREVALENCE AND ANTIBIOTIC RESISTANCE OF FOOD BORNE BACTERIAL CONTAMINATION IN SOME EGYPTIAN FOOD food

    Directory of Open Access Journals (Sweden)

    Samy Selim

    2015-09-01

    Full Text Available This study was undertaken to investigate the prevalence and antibiotic resistance of food borne bacterial contamination in some Egyptian food. Total viable bacteria and total coliform bacteriawere isolated from different sources of food; carbohydrates (bread, flour and basbousa, vegetables (outer and inner tissues of potato and outer and inner tissues of cucumber and proteins (mincedmeat, cheese and milk. The study resulted in maximum value of total viable bacteria found in outer tissue of potato 68X104±1.0, while the minimum value found in inner tissues of potato andcucumber. The study resulted in total coliform was maximum value in minced meat 6.4X103±0.3. Basbousa and inner tissue of potato and cucumber were free from coliforms. The ability of isolatesto producing proteolytic enzymes was tested, we found that 326 isolate (63.92% from all isolates had this ability, thus we selected most 2 potent proteolytic isolates. The two isolates were identifiedas Bacillus cereus and Escherichia coli. The identification confirmed by microlog 34.20 system and 16SrRNA for two isolates and the same result was founded. Sensitivity tested for the most potentproteolytic species to 12 of the most commonly used antibiotics in the Egyptian pharmacy. The results showed that all species were sensitive to most of antibiotics, except B. cereus which was strongly susceptible to azteronam and ceftazidim. The data showed that raw meat, cooked food products, and raw milk were most commonly contaminated with foodborne pathogens and many pathogens were resistant to different antibiotics. The study provided useful information for assessment of the possible risk posed to consumers, which has significant public health impact.

  15. Bacterial diversity and antibiotic resistance in water habitats: searching the links with the human microbiome.

    Science.gov (United States)

    Vaz-Moreira, Ivone; Nunes, Olga C; Manaia, Célia M

    2014-07-01

    Water is one of the most important bacterial habitats on Earth. As such, water represents also a major way of dissemination of bacteria between different environmental compartments. Human activities led to the creation of the so-called urban water cycle, comprising different sectors (waste, surface, drinking water), among which bacteria can hypothetically be exchanged. Therefore, bacteria can be mobilized between unclean water habitats (e.g. wastewater) and clean or pristine water environments (e.g. disinfected and spring drinking water) and eventually reach humans. In addition, bacteria can also transfer mobile genetic elements between different water types, other environments (e.g. soil) and humans. These processes may involve antibiotic resistant bacteria and antibiotic resistance genes. In this review, the hypothesis that some bacteria may share different water compartments and be also hosted by humans is discussed based on the comparison of the bacterial diversity in different types of water and with the human-associated microbiome. The role of such bacteria as potential disseminators of antibiotic resistance and the inference that currently only a small fraction of the clinically relevant antibiotic resistome may be known is discussed.

  16. Antibiotic resistance among cultured bacterial isolates from bioethanol fermentation facilities across the United States.

    Science.gov (United States)

    Murphree, Colin A; Heist, E Patrick; Moe, Luke A

    2014-09-01

    Bacterial contamination of fuel ethanol fermentations by lactic acid bacteria (LAB) can have crippling effects on bioethanol production. Producers have had success controlling bacterial growth through prophylactic addition of antibiotics to fermentors, yet concerns have arisen about antibiotic resistance among the LAB. Here, we report on mechanisms used by 32 LAB isolates from eight different US bioethanol facilities to persist under conditions of antibiotic stress. Minimum inhibitory concentration assays with penicillin, erythromycin, and virginiamycin revealed broad resistance to each of the antibiotics as well as high levels of resistance to individual antibiotics. Phenotypic assays revealed that antibiotic inactivation mechanisms contributed to the high levels of individual resistances among the isolates, especially to erythromycin and virginiamycin, yet none of the isolates appeared to use a β-lactamase. Biofilm formation was noted among the majority of the isolates and may contribute to persistence under low levels of antibiotics. Nearly all of the isolates carried at least one canonical antibiotic resistance gene and many carried more than one. The erythromycin ribosomal methyltransferase (erm) gene class was found in 19 of 32 isolates, yet a number of these isolates exhibit little to no resistance to erythromycin. The erm genes were present in 15 isolates that encoded more than one antibiotic resistance mechanism, suggestive of potential genetic linkages.

  17. Bacterial Etiology and Antibiotic Resistance Profile of Community-Acquired Urinary Tract Infections in a Cameroonian City

    OpenAIRE

    Rolf Nyah-tuku Nzalie; Hortense Kamga Gonsu; Sinata Koulla-Shiro

    2016-01-01

    Introduction. Community-acquired urinary tract infections (CAUTIs) are usually treated empirically. Geographical variations in etiologic agents and their antibiotic sensitivity patterns are common. Knowledge of antibiotic resistance trends is important for improving evidence-based recommendations for empirical treatment of UTIs. Our aim was to determine the major bacterial etiologies of CAUTIs and their antibiotic resistance patterns in a cosmopolitan area of Cameroon for comparison with pres...

  18. BACTERIAL CAUSES OF LOWER RESPIRATORY TRACT INFECTIONS IN PATIENTS ATTENDING CENTRAL REFERRAL HOSPITAL, GANGTOK WITH REFERENCE TO ANTIBIOTIC RESISTANCE PATTERN

    Directory of Open Access Journals (Sweden)

    Priyanka Paul

    2013-10-01

    Full Text Available ABSTRACT: BACKGROUND: There is inadequate information from India on various lower respiratory tract pathogens and their resistance pattern in hospital settings. The present study was undertaken to see the bacteriological profile an d the antibiotic resistance pattern of the isolates causing LRTI from this geographic region. OBJECTIVE: To identify and characterize bacterial pathogens causing community acquired and hospital acquired infections with reference to antibiogram pattern. MET HODS: A total of 137 samples from patients suffering from lower respiratory tract infections were studied. All the sputum samples were subjected to gram staining, culture. Various organisms were identified by standard methods. The Kirby – Bauer method was e mployed to perform the antibiotic sensitivity on Mueller Hinton agar [MHA]. For Streptococcus pneumoniae blood agar was used. MHA with 4% NaCl was used to detect methicillin resistant Staphylococcus aureus [MRSA]. RESULTS: Growth of pathogens was obtained in 66.4% of sputum samples in case of inpatients and in 33.5% outpatients. Klebsiella pneumonia [15.3%] was the predominant isolate among the inpatients whereas Streptococcus pneumonia [8.5%] was the most common pathogen isolated from outpatients. Haemophi lus influenzae was not isolated. Quinolone was found to be most effective antibiotic against gram negative organi sms. A single isolate of Morax ella catarrhalis was isolated from a case of MDR - TB. CONCLUSION : Culture and susceptibility reports should be enc ouraged before therapy to combat the problem of emergence of MDR, ESBL and MRSA strains and to subside the economic burden due to increase in cost according to the consequence of development of antibiotic resistant microbial strains

  19. Exposure of the grass shrimp, Palaemonetes pugio, to antimicrobial compounds affects associated Vibrio bacterial density and development of antibiotic resistance.

    Science.gov (United States)

    DeLorenzo, M E; Brooker, J; Chung, K W; Kelly, M; Martinez, J; Moore, J G; Thomas, M

    2016-04-01

    Antimicrobial compounds are widespread, emerging contaminants in the aquatic environment and may threaten ecosystem and human health. This study characterized effects of antimicrobial compounds common to human and veterinary medicine, aquaculture, and consumer personal care products [erythromycin (ERY), sulfamethoxazole (SMX), oxytetracycline (OTC), and triclosan (TCS)] in the grass shrimp Palaemonetes pugio. The effects of antimicrobial treatments on grass shrimp mortality and lipid peroxidation activity were measured. The effects of antimicrobial treatments on the bacterial community of the shrimp were then assessed by measuring Vibrio density and testing bacterial isolates for antibiotic resistance. TCS (0.33 mg/L) increased shrimp mortality by 37% and increased lipid peroxidation activity by 63%. A mixture of 0.33 mg/L TCS and 60 mg/L SMX caused a 47% increase in shrimp mortality and an 88% increase in lipid peroxidation activity. Exposure to SMX (30 mg/L or 60 mg/L) alone and to a mixture of SMX/ERY/OTC did not significantly affect shrimp survival or lipid peroxidation activity. Shrimp exposure to 0.33 mg/L TCS increased Vibrio density 350% as compared to the control whereas SMX, the SMX/TCS mixture, and the mixture of SMX/ERY/OTC decreased Vibrio density 78-94%. Increased Vibrio antibiotic resistance was observed for all shrimp antimicrobial treatments except for the mixture of SMX/ERY/OTC. Approximately 87% of grass shrimp Vibrio isolates displayed resistance to TCS in the control treatment suggesting a high level of TCS resistance in environmental Vibrio populations. The presence of TCS in coastal waters may preferentially increase the resistance and abundance of pathogenic bacteria. These results indicate the need for further study into the potential interactions between antimicrobials, aquatic organisms, and associated bacterial communities.

  20. Bacterial Colonization and Antibiotic Resistance in a Prospective Cohort of Newborn Infants During the First Year of Life

    Science.gov (United States)

    Stange, Kurt C.; Jacobs, Michael R.; Weiss, Judith K.; Bajaksouzian, Saralee; Bonomo, Robert A.

    2016-01-01

    Background. Infants are virtually sterile at birth and frequently use antibiotics; our objective was to (1) characterize the longitudinal colonization with bacterial pathogens and associated antibiotic resistance in a cohort of community-dwelling infants in Northeast Ohio and (2) describe longitudinal concurrent antibiotic and daycare exposures. Methods. For 35 newborns, nasopharyngeal swabs were cultured for Streptococcus pneumoniae, anterior nasal for Staphylococcus aureus, and perirectal for extended-spectrum beta-lactamase (ESBL)-producing Gram-negative enteric bacteria, at 3-month intervals for 12 months. Infant and household antibiotics and daycare exposure were assessed longitudinally. Results. Thirteen infants received perinatal or nursery antibiotics. By 3 months, at least 22 were colonized with Gram-negative bacteria; 2 with S pneumoniae (type 19A, resistant; 15C, susceptible), 5 with methicillin-susceptible S aureus. By 12 months, at least 22 of 35 infants received antibiotics, 20 had household members with antibiotics, and 12 attended daycare; 7 more had household members with daycare exposure. The ESBL-producing organisms were not identified. At least 10 infants were colonized at some time with an antibiotic-resistant organism, 3 more with pathogens displaying intermediate resistance. Pathogen colonization and resistance were intermittent and inconsistent. Conclusions. In a community-based cohort followed from birth, early antibiotic and daycare exposures are common, especially considering perinatal maternal exposures. Colonization patterns of Gram-negative bacteria, S pneumoniae, S aureus, and resistant pneumococci are strikingly dynamic. Further research can identify key areas for potential interventions to maximize clinical antibiotic outcomes while minimizing future resistance. PMID:27957505

  1. Mutations in the bacterial ribosomal protein l3 and their association with antibiotic resistance

    DEFF Research Database (Denmark)

    Klitgaard, Rasmus N; Ntokou, Eleni; Nørgaard, Katrine

    2015-01-01

    Different groups of antibiotics bind to the peptidyl transferase center (PTC) in the large subunit of the bacterial ribosome. Resistance to these groups of antibiotics has often been linked with mutations or methylations of the 23S rRNA. In recent years, there has been a rise in the number...... of studies where mutations have been found in the ribosomal protein L3 in bacterial strains resistant to PTC-targeting antibiotics but there is often no evidence that these mutations actually confer antibiotic resistance. In this study, a plasmid exchange system was used to replace plasmid-carried wild...... background. Ten plasmid-carried mutated L3 genes were constructed, and their effect on growth and antibiotic susceptibility was investigated. Additionally, computational modeling of the impact of L3 mutations in E. coli was used to assess changes in 50S structure and antibiotic binding. All mutations...

  2. Screening currency notes for microbial pathogens and antibiotic resistance genes using a shotgun metagenomic approach.

    Directory of Open Access Journals (Sweden)

    Saakshi Jalali

    Full Text Available Fomites are a well-known source of microbial infections and previous studies have provided insights into the sojourning microbiome of fomites from various sources. Paper currency notes are one of the most commonly exchanged objects and its potential to transmit pathogenic organisms has been well recognized. Approaches to identify the microbiome associated with paper currency notes have been largely limited to culture dependent approaches. Subsequent studies portrayed the use of 16S ribosomal RNA based approaches which provided insights into the taxonomical distribution of the microbiome. However, recent techniques including shotgun sequencing provides resolution at gene level and enable estimation of their copy numbers in the metagenome. We investigated the microbiome of Indian paper currency notes using a shotgun metagenome sequencing approach. Metagenomic DNA isolated from samples of frequently circulated denominations of Indian currency notes were sequenced using Illumina Hiseq sequencer. Analysis of the data revealed presence of species belonging to both eukaryotic and prokaryotic genera. The taxonomic distribution at kingdom level revealed contigs mapping to eukaryota (70%, bacteria (9%, viruses and archae (~1%. We identified 78 pathogens including Staphylococcus aureus, Corynebacterium glutamicum, Enterococcus faecalis, and 75 cellulose degrading organisms including Acidothermus cellulolyticus, Cellulomonas flavigena and Ruminococcus albus. Additionally, 78 antibiotic resistance genes were identified and 18 of these were found in all the samples. Furthermore, six out of 78 pathogens harbored at least one of the 18 common antibiotic resistance genes. To the best of our knowledge, this is the first report of shotgun metagenome sequence dataset of paper currency notes, which can be useful for future applications including as bio-surveillance of exchangeable fomites for infectious agents.

  3. Antibiotic Resistance

    Science.gov (United States)

    ... lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able ... resistant to several common antibiotics. To help prevent antibiotic resistance Don't use antibiotics for viruses like colds ...

  4. Antibiotic resistance in Chlamydiae.

    Science.gov (United States)

    Sandoz, Kelsi M; Rockey, Daniel D

    2010-09-01

    There are few documented reports of antibiotic resistance in Chlamydia and no examples of natural and stable antibiotic resistance in strains collected from humans. While there are several reports of clinical isolates exhibiting resistance to antibiotics, these strains either lost their resistance phenotype in vitro, or lost viability altogether. Differences in procedures for chlamydial culture in the laboratory, low recovery rates of clinical isolates and the unknown significance of heterotypic resistance observed in culture may interfere with the recognition and interpretation of antibiotic resistance. Although antibiotic resistance has not emerged in chlamydiae pathogenic to humans, several lines of evidence suggest they are capable of expressing significant resistant phenotypes. The adept ability of chlamydiae to evolve to antibiotic resistance in vitro is demonstrated by contemporary examples of mutagenesis, recombination and genetic transformation. The isolation of tetracycline-resistant Chlamydia suis strains from pigs also emphasizes their adaptive ability to acquire antibiotic resistance genes when exposed to significant selective pressure.

  5. Antibiotic resistance genes in bacterial and bacteriophage fractions of Tunisian and Spanish wastewaters as markers to compare the antibiotic resistance patterns in each population.

    Science.gov (United States)

    Colomer-Lluch, Marta; Calero-Cáceres, William; Jebri, Sihem; Hmaied, Fatma; Muniesa, Maite; Jofre, Juan

    2014-12-01

    The emergence and increased prevalence of antibiotic resistance genes (ARGs) in the environment may pose a serious global health concern. This study evaluates the abundance of several ARGs in bacterial and bacteriophage DNA via real-time qPCR in samples from five different sampling points in Tunisia; three wastewater treatment plants (WWTP 1, 2 and 3) and wastewater from two abattoirs slaughtering different animals. Results are compared with those obtained in the Barcelona area, in northeast Spain. Eight ARGs were quantified by qPCR from total and phage DNA fraction from the samples. Three β-lactamases (bla(TEM), bla(CTX-M) cluster 1 and bla(CTX-M) cluster 9), two quinolone resistance genes (qnrA and qnrS), the mecA gene that confers resistance to methicillin in Staphylococcus aureus, the emerging armA gene, conferring resistance to aminoglycosides and sul1, the most extended gene conferring resistance to sulfonamides, were evaluated. Sul1 and bla(TEM) were the most prevalent ARGs detected at all five Tunisian sampling points, similarly with the observations in Barcelona. bla(CTX-M-9) was more prevalent than bla(CTX-M-1) both in bacterial and DNA within phage particles in all samples analysed. mecA and armA were almost absent in Tunisian waters from human or animal origin in contrast with Barcelona that showed a medium prevalence. qnrA was more prevalent than qnrS in bacterial and phage DNA from all sampling points. In conclusion, our study shows that ARGs are found in the bacterial and is reflected in the phage DNA fraction of human and animal wastewaters. The densities of each ARGs vary depending on the ARGs shed by each population and is determined by the characteristics of each area. Thus, the evaluation of ARGs in wastewaters seems to be suitable as marker reflecting the antibiotic resistance patterns of a population.

  6. Antibiotic resistance and pathogenicity factors in Staphylococcus aureus isolated from mastitic Sahiwal cattle

    Indian Academy of Sciences (India)

    Ravinder Kumar; B R Yadav; R S Singh

    2011-03-01

    Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious problem in dairy animals suffering from mastitis. In the present study, the distribution of mastitic MRSA and antibiotic resistance was studied in 107 strains of S. aureus isolated from milk samples from 195 infected udders. The characterizations pathogenic factors (adhesin and toxin genes) and antibiotic susceptibility of isolates were carried out using gene amplification and disc diffusion assays, respectively. A high prevalence of MRSA was observed in the tested isolates (13.1%). The isolates were also highly resistant to antibiotics, i.e. 36.4% were resistant to streptomycin, 33.6% to oxytetracycline, 29.9% to gentamicin and 26.2% each to chloramphenicol, pristinomycin and ciprofloxacin. A significant variation in the expression of pathogenic factors (Ig, coa and clf) was observed in these isolates. The overall distribution of adhesin genes ebp, fib, bbp, fnbB, cap5, cap8, map and cna in the isolates was found to be 69.1, 67.2, 6.5, 20.5, 60.7, 26.1, 81.3 and 8.4%, respectively. The presence of fib, fnbB, bbp and map genes was considerably greater in MRSA than in methicillin-susceptible S. aureus (MSSA) isolates. The proportions of toxin genes, namely, hlb, seb, sec, sed, seg and sei, in the isolates were found to be 94.3, 0.9, 8.4, 0.9, 10.2 and 49.5%, respectively. The proportions of agr genes I, II, III and IV were found to be 39.2, 27.1, 21.5 and 12.1%, respectively. A few isolates showed similar antibiotic-resistance patterns, which could be due to identical strains or the dissemination of the same strains among animals. These findings can be utilized in mastitis treatment programmes and antimicrobials strategies in organized herds.

  7. Cultivation and qPCR detection of pathogenic and antibiotic resistant bacteria establishment in naive broiler houses

    Science.gov (United States)

    : 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 ...

  8. A novel cysteine-free venom peptide with strong antimicrobial activity against antibiotics-resistant pathogens from the scorpion Opistophthalmus glabrifrons.

    Science.gov (United States)

    Bao, Aorigele; Zhong, Jie; Zeng, Xian-Chun; Nie, Yao; Zhang, Lei; Peng, Zhao Feng

    2015-10-01

    Antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus, pose serious threat to human health. The outbreak of antibiotic-resistant pathogens in recent years emphasizes once again the urgent need for the development of new antimicrobial agents. Here, we discovered a novel antimicrobial peptide from the scorpion Opistophthalmus glabrifrons, which was referred to as Opisin. Opisin consists of 19 amino acid residues without disulfide bridges. It is a cationic, amphipathic, and α-helical molecule. Protein sequence homology search revealed that Opisin shares 42.1-5.3% sequence identities to the 17/18-mer antimicrobial peptides from scorpions. Antimicrobial assay showed that Opisin is able to potently inhibit the growth of the tested Gram-positive bacteria with the minimal inhibitory concentration (MIC) values of 4.0-10.0 μM; in contrast, it possesses much lower activity against the tested Gram-negative bacteria and a fungus. It is interesting to see that Opisin is able to strongly inhibit the growth of methicillin- and vancomycin-resistant pathogens with the MICs ranging from 2.0 to 4.0 μM and from 4.0 to 6.0 μM, respectively. We found that at a concentration of 5 × MIC, Opisin completely killed all the cultured methicillin-resistant Staphylococcus aureus. These results suggest that Opisin is a promising therapeutic candidate for the treatment of the antibiotic-resistant bacterial infections.

  9. Chemical communication of antibiotic resistance by a highly resistant subpopulation of bacterial cells.

    Directory of Open Access Journals (Sweden)

    Omar M El-Halfawy

    Full Text Available The overall antibiotic resistance of a bacterial population results from the combination of a wide range of susceptibilities displayed by subsets of bacterial cells. Bacterial heteroresistance to antibiotics has been documented for several opportunistic Gram-negative bacteria, but the mechanism of heteroresistance is unclear. We use Burkholderia cenocepacia as a model opportunistic bacterium to investigate the implications of heterogeneity in the response to the antimicrobial peptide polymyxin B (PmB and also other bactericidal antibiotics. Here, we report that B. cenocepacia is heteroresistant to PmB. Population analysis profiling also identified B. cenocepacia subpopulations arising from a seemingly homogenous culture that are resistant to higher levels of polymyxin B than the rest of the cells in the culture, and can protect the more sensitive cells from killing, as well as sensitive bacteria from other species, such as Pseudomonas aeruginosa and Escherichia coli. Communication of resistance depended on upregulation of putrescine synthesis and YceI, a widely conserved low-molecular weight secreted protein. Deletion of genes for the synthesis of putrescine and YceI abrogate protection, while pharmacologic inhibition of putrescine synthesis reduced resistance to polymyxin B. Polyamines and YceI were also required for heteroresistance of B. cenocepacia to various bactericidal antibiotics. We propose that putrescine and YceI resemble "danger" infochemicals whose increased production by a bacterial subpopulation, becoming more resistant to bactericidal antibiotics, communicates higher level of resistance to more sensitive members of the population of the same or different species.

  10. Strain-Specific Transfer of Antibiotic Resistance from an Environmental Plasmid to Foodborne Pathogens

    Directory of Open Access Journals (Sweden)

    Eva Van Meervenne

    2012-01-01

    Full Text Available Pathogens resistant to multiple antibiotics are rapidly emerging, entailing important consequences for human health. This study investigated if the broad-host-range multiresistance plasmid pB10, isolated from a wastewater treatment plant, harbouring amoxicillin, streptomycin, sulfonamide, and tetracycline resistance genes, was transferable to the foodborne pathogens Salmonella spp. or E. coli O157:H7 and how this transfer alters the phenotype of the recipients. The transfer ratio was determined by both plating and flow cytometry. Antibiotic resistance profiles were determined for both recipients and transconjugants using the disk diffusion method. For 14 of the 15 recipient strains, transconjugants were detected. Based on plating, transfer ratios were between 6.8×10−9 and 3.0×10−2 while using flow cytometry, transfer ratios were between <1.0×10−5 and 1.9×10−2. With a few exceptions, the transconjugants showed phenotypically increased resistance, indicating that most of the transferred resistance genes were expressed. In summary, we showed that an environmental plasmid can be transferred into foodborne pathogenic bacteria at high transfer ratios. However, the transfer ratio seemed to be recipient strain dependent. Moreover, the newly acquired resistance genes could turn antibiotic susceptible strains into resistant ones, paving the way to compromise human health.

  11. Epidemiology and antibiotic resistance of bacterial meningitis in Dapaong, northern Togo

    Institute of Scientific and Technical Information of China (English)

    Simplice D Karou; Abago Balaka; Mitiname Bamok; Damhan Tchelougou; Malki Assih; Kokou Anani; Kodjo Agbonoko; Jacques Simpore; Comlan de Souza

    2012-01-01

    Objective:To assess the seasonality of the bacterial meningitis and the antibiotic resistance of incriminated bacteria over the last three years in the northern Togo. Methods: From January 2007 to January 2010, 533 cerebrospinal fluids (CSF) samples were collected from patients suspected of meningitis in the Regional Hospital of Dapaong (northern Togo). After microscopic examination, samples were cultured for bacterial identification and antibiotic susceptibility. Results:The study included 533 patients (306 male and 227 female) aged from 1 day to 55 years [average age (13.00±2.07) years]. Bacterial isolation and identification were attempted for 254/533 (47.65%) samples. The bacterial species identified were:Neisseria meningitidis A (N. meningitidis A) (58.27%), Neisseria meningitidis W135 (N. meningitidis W135) (7.09%), Streptococcus pneumoniae (S. pneumoniae) (26.77%), Haemophilus influenza B (H. influenza B) (6.30%) and Enterobacteriaceae (1.57%). The results indicated that bacterial meningitis occur from November to May with a peak in February for H. influenzae and S. pneumoniae and March for Neisseriaceae. The distribution of positive CSF with regards to the age showed that subjects between 6 and 12 years followed by subjects of 0 to 5 years were most affected with respective frequencies of 67.82% and 56.52% (P20%for both bacterial strains), macrolides (resistance rate> 30%for H. influenzae) quinolones (resistance rate>15%for H. influenzae and N. meningitidis W135). Over three years, the prevalence of S. pneumoniae significantly increased from 8.48%to 73.33%(P<0.001), while the changes in the prevalence of H. influenzae B were not statistically significant: 4.24%, vs. 8.89%, (P= 0.233). Conclusions:Our results indicate that data in African countries differ depending on geographical location in relation to the African meningitis belt. This underlines the importance of epidemiological surveillance of bacterial meningitis.

  12. Antibiotic resistance genes occurrence and bacterial community composition in the Liuxi River

    Directory of Open Access Journals (Sweden)

    Wenguang eXiong

    2014-12-01

    Full Text Available Antibiotic resistance genes (ARGs in the environment have paid great concern due to their health risk. We investigated antibiotics concentrations (tetracyclines, sulfonamides and fluoroquinolones, ARGs abundances (tetracycline, sulfonamide and plasmid-mediated quinolone resistance (PMQR genes, and bacterial community composition in sediment and water samples in the Liuxi River, China. Antibiotics concentrations were determined by ultra-performance liquid chromatography-electrospray tandem mass spectrometry. ARGs abundances were quantified by a culture-independent method. Bacterial community composition was analyzed by metagenomic approach based on Ion Torrent Personal Genome Machine platform. Antibiotics concentrations were at the levels of 1.19 to 622 ug kg-1 in sediment samples and below the limit of detection to 127 ng L-1 in water samples. Relative abundances (ARGs copies/16S rRNA gene copies of detected ARGs were at the range of 10-5 to 10-2. The dominant phyla were Proteobacteria, Bacteroidetes and Verrucomicrobia in sediment samples, and were Proteobacteria, Actinobacteria and Bacteroidetes in water samples. The results indicated that the river environment was contaminated by antibiotics and may be as a reservoir of ARGs. This study provided quantitative data on antibiotics, ARGs and bacterial community composition in the Liuxi River, a geographical location different from the reported studies.

  13. Conjunctival bacterial flora and antibiotic resistance pattern in patients undergoing cataract surgery

    Directory of Open Access Journals (Sweden)

    Arantes Tiago Eugênio Faria e

    2006-01-01

    Full Text Available PURPOSE: To evaluate the conjunctival bacterial flora and its antibiotic resistance pattern in eyes of patients undergoing cataract surgery. METHODS: From August to October 2004, 50 patients undergoing cataract surgery in the "Fundação Altino Ventura", Recife, Brazil, were prospectively evaluated. Conjunctival material was obtained on the day of surgery, before the application of topical anesthetic, antibiotic or povidone-iodine. The collected material was inoculated and bacterioscopic analysis was carried out. In the cases where there was bacterial growth, antibiotic susceptibility tests and cultures, for isolation and identification of the bacteria, were performed. RESULTS: Of the 50 eyes, 43 (86.0% had positive cultures. The coagulase-negative Staphylococcus (CNS, found in 27 (54.0% eyes, was the most frequent organism. More than 90% of the isolates of this bacterium were susceptible to cephalotin, vancomycin, chloramphenicol, ofloxacin and gatifloxacin; 70 to 90% were susceptible to gentamicin, cefotaxime, oxacillin and ciprofloxacin; and less than 70% were sensible to neomycin. Four (10.5% of the bacterial isolates were resistant to four or more antibiotics, two of them were CNS. CONCLUSION: The most frequent bacterium in the conjunctival flora is the coagulase-negative Staphylococcus. The isolates of this organism showed low susceptibility rate to neomycin, and high susceptibility rates to cephalotin, vancomycin, chloramphenicol, ofloxacin and gatifloxacin.

  14. Impact of fertilizing with raw or anaerobically digested sewage sludge on the abundance of antibiotic-resistant coliforms, antibiotic resistance genes, and pathogenic bacteria in soil and on vegetables at harvest.

    Science.gov (United States)

    Rahube, Teddie O; Marti, Romain; Scott, Andrew; Tien, Yuan-Ching; Murray, Roger; Sabourin, Lyne; Zhang, Yun; Duenk, Peter; Lapen, David R; Topp, Edward

    2014-11-01

    The consumption of crops fertilized with human waste represents a potential route of exposure to antibiotic-resistant fecal bacteria. The present study evaluated the abundance of bacteria and antibiotic resistance genes by using both culture-dependent and molecular methods. Various vegetables (lettuce, carrots, radish, and tomatoes) were sown into field plots fertilized inorganically or with class B biosolids or untreated municipal sewage sludge and harvested when of marketable quality. Analysis of viable pathogenic bacteria or antibiotic-resistant coliform bacteria by plate counts did not reveal significant treatment effects of fertilization with class B biosolids or untreated sewage sludge on the vegetables. Numerous targeted genes associated with antibiotic resistance and mobile genetic elements were detected by PCR in soil and on vegetables at harvest from plots that received no organic amendment. However, in the season of application, vegetables harvested from plots treated with either material carried gene targets not detected in the absence of amendment. Several gene targets evaluated by using quantitative PCR (qPCR) were considerably more abundant on vegetables harvested from sewage sludge-treated plots than on vegetables from control plots in the season of application, whereas vegetables harvested the following year revealed no treatment effect. Overall, the results of the present study suggest that producing vegetable crops in ground fertilized with human waste without appropriate delay or pretreatment will result in an additional burden of antibiotic resistance genes on harvested crops. Managing human exposure to antibiotic resistance genes carried in human waste must be undertaken through judicious agricultural practice.

  15. POTENCY OF HONEY AS ANTIBACTERIAL AGENT AGAINST MULTIPLE ANTIBIOTIC RESISTANT PATHOGENS EVALUATED BY DIFFERENT METHODS

    Directory of Open Access Journals (Sweden)

    Mohamed Mustafa Aween

    2014-01-01

    Full Text Available Honey is rich with complex natural components which could be useful as antibacterial agents or as preservative. Honey contains high concentration of sugars, low amount of water, high osmolality and often dark colour which influence its antibacterial activity. Disc diffusion, well method, micro dilution assay are methods commonly used to determine the antibacterial activity of honey. In this study, microtiter and microbial plate count were included to ascertain the potency of honey as antibacterial agent against multiple antibiotic resistant pathogenic bacteria (Staphylococcus aureus, Salmonella Typhimurium, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa with concentration of 0.2 g mL-1. Results found that well diffusion method tends to give higher inhibitory zone than disc diffusion method but there was no correlation among the bacteria was observed except for S. Typhimurium, E. coli (R = 0.310, 0.505 and 0.316, respectively. Nan photometer assay and microtiter plates assay showed comparable results with moderately strong correlation (R2 = 0.681 and 0.767, respectively for S. aureus and S. typhimurium, but poor correlation was found for E. coli, B. subtilis and P. aeruginosa (R2 = 0.441, 0.308 and 0.383, respectively. Determining the number of survivors by plating on agar after nanophotometer assay or microtiter plate assay had confirmed the effectiveness of honey as antimicrobial agent against target bacteria; which confirmed that honey has the potency to inhibit pathogens even at low concentration.

  16. Analyzing indicator microorganisms, antibiotic resistant Escherichia coli, and regrowth potential of foodborne pathogens in various organic fertilizers.

    Science.gov (United States)

    Miller, Cortney; Heringa, Spencer; Kim, Jinkyung; Jiang, Xiuping

    2013-06-01

    This study analyzed various organic fertilizers for indicator microorganisms, pathogens, and antibiotic-resistant Escherichia coli, and evaluated the growth potential of E. coli O157:H7 and Salmonella in fertilizers. A microbiological survey was conducted on 103 organic fertilizers from across the United States. Moisture content ranged from approximately 1% to 86.4%, and the average pH was 7.77. The total aerobic mesophiles ranged from approximately 3 to 9 log colony-forming units (CFU)/g. Enterobacteriaceae populations were in the range of fertilizer, respectively, whereas E. coli O157:H7 grew approximately 4.6, 4.0, 4.0, and 4.8 log CFU/g, respectively. Our results revealed that the microbiological quality of organic fertilizers varies greatly, with some fertilizers containing antibiotic resistant E. coli and a few supporting the growth of foodborne pathogens after reintroduction into the fertilizer.

  17. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes

    Science.gov (United States)

    Wang, Hang; Li, Hongyi; Gilbert, Jack A.; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang

    2015-01-01

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P vermicomposting, accompanied by a 100 times increase in the relative abundance of Flavobacteriaceae spp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the family Ruminococcaceae, class Bacilli, or phylum Proteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to attenuate the dissemination of antimicrobial residues and ARGs from livestock production before vermicompost can be safely used as biofertilizer in agroecosystems. PMID:26296728

  18. Development of antibiotic-resistant strains for the enumeration of foodborne pathogenic bacteria in stored foods.

    Science.gov (United States)

    Blackburn, C D; Davies, A R

    1994-12-01

    Strains of Aeromonas spp., Salmonella enteritidis phage type 4, Salmonella typhimurium, verotoxigenic Escherichia coli O157:H7 (VTEC) and Yersinia enterocolitica resistant to streptomycin, nalidixic acid and a combination of both antibiotics were selected. When compared with the parent strains, most of the antibiotic-resistant strains had slightly slower growth rates at their optimum incubation temperature but the difference was reduced progressively when the temperature was lowered. Some antibiotic-resistant strains had considerably slower growth rates in the presence of the relevant antibiotic and these were not used further. Several agar and impedance media with added streptomycin and nalidixic acid were assessed for the enumeration of the antibiotic-resistant strains in artificially contaminated stored foods. Differential/selective media were required to enumerate low numbers of antibiotic-resistant strains in certain foods. The following agar and impedance media were selected: Aeromonas Agar (Ryan) for Aeromonas spp., Xylose Lysine Agar and Lysine Iron Cysteine Neutral Red Medium for Salmonella, Eosin Methylene Blue Agar and Coliform Medium for VTEC, and Yersinia Selective Agar without selective agents for Yersinia enterocolitica. The agar and impedance media have been used successfully to enumerate antibiotic-resistant strains inoculated into foods and stored at different temperatures.

  19. The Antibiotic Resistance Profiles of Bacterial Strains Isolated from Patients with Hospital-Acquired Bloodstream and Urinary Tract Infections

    Directory of Open Access Journals (Sweden)

    Hamed Ghadiri

    2012-01-01

    Full Text Available Treatment of nosocomial infections is becoming difficult due to the increasing trend of antibiotics resistance. Current knowledge on antibiotic resistance pattern is essential for appropriate therapy. We aimed to evaluate antibiotic resistance profiles in nosocomial bloodstream and urinary tract pathogens. A total of 129 blood stream and 300 urinary tract positive samples were obtained from patients referring to Besat hospital over a two-year period (2009 and 2010. Antibiotic sensitivity was ascertained using the Kirby-Bauer disk diffusion technique according to CLSI guidelines. Patient's data such as gender and age were recorded. The ratio of gram-negative to gram-positive bacteria in BSIs was 1.6 : 1. The most prevalent BSI pathogen was Coagulase-Negative Staphylococci (CoNS. The highest resistance rate of CoNS was against penicillin (91.1% followed by ampicillin (75.6%, and the lowest rate was against vancomycin (4.4%. Escherichia coli was the most prevalent pathogen isolated from urinary tract infections (UTIs. Ratio of gram-negative to gram-positive bacteria was 3.2 : 1. The highest resistance rate of E. coli isolates was against nalidixic acid (57.7%. The present study showed that CoNS and E. coli are the most common causative agents of nosocomial BSIs and UTIs, and control of infection needs to be addressed in both antibiotic prescription and general hygiene.

  20. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes.

    Science.gov (United States)

    Wang, Hang; Li, Hongyi; Gilbert, Jack A; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang; Zhang, Zhijian

    2015-11-01

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P < 0.05), while those of genes encoding sulfonamide resistance (sul1 and sul2) were increased (P < 0.05) when normalized to 16S rRNA. The abundances of tetracycline resistance genes were correlated (P < 0.05) with the changing concentrations of tetracyclines in the manure. The overall diversity and richness of the bacteria significantly decreased during vermicomposting, accompanied by a 100 times increase in the relative abundance of Flavobacteriaceae spp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the family Ruminococcaceae, class Bacilli, or phylum Proteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to attenuate the dissemination of antimicrobial residues and ARGs from livestock production before vermicompost can be safely used as biofertilizer in agroecosystems.

  1. Trends in antibiotic resistance of corneal pathogens: Part I. An analysis of commonly used ocular antibiotics

    Directory of Open Access Journals (Sweden)

    Sharma Savitri

    1999-01-01

    Full Text Available Purpose: To analyse commonly used ocular antibiotics and determine their in-vitro efficacies against bacterial keratitis pathogens. Methods: A retrospective review of microbiology records at the LV Prasad Eye Institute in Hyderabad, India identified 1,633 bacterial keratitis isolates. Antibiotic susceptibility of corneal isolates was determined for various ocular antibiotics using the Kirby-Bauer disc-diffusion method. Results: Cefazolin had coverage against 1,296 (83.0% of 1,562 isolates tested; chloramphenicol against 1,136 (71.7% of 1,585 isolates; ciprofloxacin against 1,080 (69.3% of 1,558 isolates; gentamicin against 1,106 (70.6% of 1,567 isolates; norfloxacin against 1,057 (67.7% of 1,561 isolates; vancomycin against 463 (84.3% of 549 isolates; and framycetin against 105 (36.2% of 290 isolates. Also included is a breakdown by species, and sensitivity profiles for resistant isolates.Conclusion: This study provides information on the efficacies of ocular antibiotics commonly used against bacterial keratitis pathogens. It also examines the antibiotic susceptibility profiles for corneal pathogens that are resistant to an ocular antibiotic but sensitive to other selected antibiotics. It is hoped that this information will aid in the decision-making of empiric initial treatment of bacterial keratitis.

  2. The neglected intrinsic resistome of bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Alicia Fajardo

    Full Text Available Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature.

  3. The Neglected Intrinsic Resistome of Bacterial Pathogens

    Science.gov (United States)

    Fajardo, Alicia; Martínez-Martín, Nadia; Mercadillo, María; Galán, Juan C.; Ghysels, Bart; Matthijs, Sandra; Cornelis, Pierre; Wiehlmann, Lutz; Tümmler, Burkhard; Baquero, Fernando; Martínez, José L.

    2008-01-01

    Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature. PMID:18286176

  4. Antibiotic-Resistant Acinetobacter baumannii Increasing Success Remains a Challenge as a Nosocomial Pathogen

    OpenAIRE

    Ana Maria Gonzalez-Villoria; Veronica Valverde-Garduno

    2016-01-01

    Antibiotic-resistant infectious bacteria currently imply a high risk and therefore constitute a strong challenge when treating patients in hospital settings. Characterization of these species and of particular strains is a priority for the establishment of diagnostic tests and preventive procedures. The relevance of Acinetobacter baumannii as a problematic microorganism in inpatient facilities, particularly intensive care units, has increased over time. This review aims to draw attention to (...

  5. Antibiotic-Resistant Acinetobacter baumannii Increasing Success Remains a Challenge as a Nosocomial Pathogen

    Directory of Open Access Journals (Sweden)

    Ana Maria Gonzalez-Villoria

    2016-01-01

    Full Text Available Antibiotic-resistant infectious bacteria currently imply a high risk and therefore constitute a strong challenge when treating patients in hospital settings. Characterization of these species and of particular strains is a priority for the establishment of diagnostic tests and preventive procedures. The relevance of Acinetobacter baumannii as a problematic microorganism in inpatient facilities, particularly intensive care units, has increased over time. This review aims to draw attention to (i the historical emergence of carbapenem-resistant Acinetobacter baumannii, (ii the current status of surveillance needs in Latin America, and (iii recent data suggesting that A. baumannii continues to spread and evolve in hospital settings. First, we present synopsis of the series of events leading to the discovery and precise identification of this microorganism in hospital settings. Then key events in the acquisition of antibiotic-resistant genes by this microorganism are summarized, highlighting the race between new antibiotic generation and emergence of A. baumannii resistant strains. Here we review the historical development of this species as an infectious threat, the current state of its distribution, and antibiotic resistance characteristics, and we discuss future prospects for its control.

  6. Prevalence of antibiotic resistance genes and bacterial community composition in a river influenced by a wastewater treatment plant.

    Directory of Open Access Journals (Sweden)

    Elisabet Marti

    Full Text Available Antibiotic resistance represents a global health problem, requiring better understanding of the ecology of antibiotic resistance genes (ARGs, their selection and their spread in the environment. Antibiotics are constantly released to the environment through wastewater treatment plant (WWTP effluents. We investigated, therefore, the effect of these discharges on the prevalence of ARGs and bacterial community composition in biofilm and sediment samples of a receiving river. We used culture-independent approaches such as quantitative PCR to determine the prevalence of eleven ARGs and 16S rRNA gene-based pyrosequencing to examine the composition of bacterial communities. Concentration of antibiotics in WWTP influent and effluent were also determined. ARGs such as qnrS, bla TEM, bla CTX-M, bla SHV, erm(B, sul(I, sul(II, tet(O and tet(W were detected in all biofilm and sediment samples analyzed. Moreover, we observed a significant increase in the relative abundance of ARGs in biofilm samples collected downstream of the WWTP discharge. We also found significant differences with respect to community structure and composition between upstream and downstream samples. Therefore, our results indicate that WWTP discharges may contribute to the spread of ARGs into the environment and may also impact on the bacterial communities of the receiving river.

  7. Assessment of anaerobic bacterial diversity and its effects on anaerobic system stability and the occurrence of antibiotic resistance genes.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2016-05-01

    This study evaluated the link between anaerobic bacterial diversity and, the biodegradation of antibiotic combinations and assessed how amending antibiotic combination and increasing concentration of antibiotics in a stepwise fashion influences the development of resistance genes in anaerobic reactors. The biodegradation, sorption and occurrence of the known antibiotic resistance genes (ARGs) of erythromycin and tetracycline were investigated using the processes of UV-HPLC and qPCR analysis respectively. Ion Torrent sequencing was used to detect microbial community changes in response to the addition of antibiotics. The overall results indicated that changes in the structure of a microbial community lead to changes in biodegradation capacity, sorption of antibiotics combinations and occurrence of ARGs. The enhanced biodegradation efficiency appeared to generate variations in the structure of the bacterial community. The results suggested that controlling the ultimate Gram-negative bacterial community, especially Acinetobacter-related populations, may promote the successful biodegradation of antibiotic combinations and reduce the occurrence of ARGs.

  8. Consolidating and Exploring Antibiotic Resistance Gene Data Resources

    DEFF Research Database (Denmark)

    Xavier, Basil Britto; Das, Anupam J.; Cochrane, Guy

    2016-01-01

    The unrestricted use of antibiotics has resulted in rapid acquisition of antibiotic resistance (AR) and spread of multidrug-resistant (MDR) bacterial pathogens. With the advent of next-generation sequencing technologies and their application in understanding MDR pathogen dynamics, it has become...

  9. Removal of bacterial contaminants and antibiotic resistance genes by conventional wastewater treatment processes in Saudi Arabia: Is the treated wastewater safe to reuse for agricultural irrigation?

    KAUST Repository

    Aljassim, Nada I.

    2015-04-01

    This study aims to assess the removal efficiency of microbial contaminants in a local wastewater treatment plant over the duration of one year, and to assess the microbial risk associated with reusing treated wastewater in agricultural irrigation. The treatment process achieved 3.5 logs removal of heterotrophic bacteria and up to 3.5 logs removal of fecal coliforms. The final chlorinated effluent had 1.8×102 MPN/100mL of fecal coliforms and fulfils the required quality for restricted irrigation. 16S rRNA gene-based high-throughput sequencing showed that several genera associated with opportunistic pathogens (e.g. Acinetobacter, Aeromonas, Arcobacter, Legionella, Mycobacterium, Neisseria, Pseudomonas and Streptococcus) were detected at relative abundance ranging from 0.014 to 21 % of the total microbial community in the influent. Among them, Pseudomonas spp. had the highest approximated cell number in the influent but decreased to less than 30 cells/100mL in both types of effluent. A culture-based approach further revealed that Pseudomonas aeruginosa was mainly found in the influent and non-chlorinated effluent but was replaced by other Pseudomonas spp. in the chlorinated effluent. Aeromonas hydrophila could still be recovered in the chlorinated effluent. Quantitative microbial risk assessment (QMRA) determined that only chlorinated effluent should be permitted for use in agricultural irrigation as it achieved an acceptable annual microbial risk lower than 10-4 arising from both P. aeruginosa and A. hydrophila. However, the proportion of bacterial isolates resistant to 6 types of antibiotics increased from 3.8% in the influent to 6.9% in the chlorinated effluent. Examples of these antibiotic-resistant isolates in the chlorinated effluent include Enterococcus and Enterobacter spp. Besides the presence of antibiotic-resistant bacterial isolates, tetracycline resistance genes tetO, tetQ, tetW, tetH, tetZ were also present at an average 2.5×102, 1.6×102, 4.4×102, 1

  10. Steering Evolution with Sequential Therapy to Prevent the Emergence of Bacterial Antibiotic Resistance.

    Directory of Open Access Journals (Sweden)

    Daniel Nichol

    2015-09-01

    Full Text Available The increasing rate of antibiotic resistance and slowing discovery of novel antibiotic treatments presents a growing threat to public health. Here, we consider a simple model of evolution in asexually reproducing populations which considers adaptation as a biased random walk on a fitness landscape. This model associates the global properties of the fitness landscape with the algebraic properties of a Markov chain transition matrix and allows us to derive general results on the non-commutativity and irreversibility of natural selection as well as antibiotic cycling strategies. Using this formalism, we analyze 15 empirical fitness landscapes of E. coli under selection by different β-lactam antibiotics and demonstrate that the emergence of resistance to a given antibiotic can be either hindered or promoted by different sequences of drug application. Specifically, we demonstrate that the majority, approximately 70%, of sequential drug treatments with 2-4 drugs promote resistance to the final antibiotic. Further, we derive optimal drug application sequences with which we can probabilistically 'steer' the population through genotype space to avoid the emergence of resistance. This suggests a new strategy in the war against antibiotic-resistant organisms: drug sequencing to shepherd evolution through genotype space to states from which resistance cannot emerge and by which to maximize the chance of successful therapy.

  11. Antibiotic resistance and trend of urinary pathogens in general outpatients from a major urban city

    Directory of Open Access Journals (Sweden)

    Carlos R. Kiffer

    2007-02-01

    Full Text Available OBJECTIVE: We assessed the antimicrobial resistance patterns of pathogens responsible for urinary tract infections (UTI in outpatients in São Paulo, Brazil, as well as the Escherichia coli antimicrobial resistance trend. MATERIALS AND METHODS: Outpatients urine cultures were collected from January 2000 to December 2003. Statistical analysis considered positive results for one bacterial species with colony count > 100,000 CFU/mL. Stratification was done on age group and gender. Statistical tests used included chi-square and the chi-square test for trend to evaluate differences between susceptibility rates among age groups and ordering in the E. coli resistance rates per year, respectively. RESULTS: There were 37,261 positive results with Enterobacteriaceae isolated in 32,530 (87.3% and Gram-positive cocci in 2,570 (6.9% cultures. E. coli had the highest prevalence (71.6%. Susceptibility tests were performed in 31,716 cultures. E. coli had elevated resistance rates (> 30% to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline. Significant differences between age groups and ordering among years were observed. CONCLUSIONS: The use of trimethoprim-sulfamethoxazole is precluded in the population studied due to elevated resistance rates (> 30% among most prevalent pathogens. Significant resistance rate differences among age groups and years were observed, particularly for fluoroquinolones. Fluoroquinolones should be used with caution. Nitrofurantoin should be used as empirical therapy for primary, non-complicated urinary tract infections.

  12. Epidemiology of antibiotic resistance in Burkina Faso

    Institute of Scientific and Technical Information of China (English)

    Simpore J; Zeba B; Karou D; Ilboudo D; Pignatelli S; Nacoulma OG; Musumeci S

    2008-01-01

    Burkina Faso (West Africa)is a tropical country with a high incidence of infectious diseases.The uncontrolled use of antibiotics against bacterial pathogens has given rise to the emergence of antibiotic resistance in this country.The aims of this study were.i)to determine the prevalences of the most important pathogenic bacteri-a,isolated in the town of Ouagadougou.ii)to identify the bacterial species which have acquired resistance as a result of antibiotic selection.iii)to compare antibiotic-resistances ofEscherichia coli isolated from stool cul-ture in the present study,with results obtained in 2002 from strains collected in the same structure in Burkina Faso.iv)to determine the trend of antibiotic resistance in Burkina Faso in order to give local advice on the most appropriate empiric antibiotic therapy.Six thousand two hundred and sixty four samples of blood,stools, urine,sputum,pus and vaginal secretion were collected and analyzed in Saint Camille Medical Center (SC-MC)laboratory from May 2001 to May 2006.Out of the 6264 samples tested no pathogen was identified in 1583 (25.31%),whilst 4681 (74.73%)were positive,with the incidence of the microrganisms isolated be-ing as follows:Escherichia coli 1291 (27.6%),Staphylococcus aureus 922 (19.7%),Salmonella spp 561 (12.0%),Streptococcus spp 499 (10.7%),Klebsiella spp 359 (7.7%),Shigella spp (6.3%),Acineto-bacter spp 266 (5.7%)and others 783 (16.7%).Among the isolated pathogens,the highest resistance was found to Amoxycillin:Proteus spp 95.6%,Escherichia coli 78.2%,Salmonella spp 62.2%,Shigella spp 73. 4% and Klebsiella spp 89.9%,followed by resistance to Ampicillin and cotrimoxazole.Comparing the preva-lence of antibiotic resistance of Escherichia coli from stool cultures isolated during 1999-2000 to that of 2001-2006,a significant reduction was found,which could be due to the improved use of antibiotics in recent years. The reduced antibiotic-resistance observed in pathogens isolated in Burkina Faso during this

  13. Copper amendment of agricultural soil selects for bacterial antibiotic resistance in the field

    DEFF Research Database (Denmark)

    Berg, J.; Tom-Petersen, A.; Nybroe, O.

    2005-01-01

    Aims: The objective of this study was to determine whether Cu-amendment of field plots affects the frequency of Cu resistance, and antibiotic resistance patterns in indigenous soil bacteria. Methods and Results: Soil bacteria were isolated from untreated and Cu-amended field plots. Cu......-amendment significantly increased the frequency of Cu-resistant isolates. A panel of isolates were characterized by Gram-reaction, amplified ribosomal DNA restriction analysis and resistance profiling against seven antibiotics. More than 95% of the Cu-resistant isolates were Gram-negative. Cu-resistant Gram......-negative isolates had significantly higher incidence of resistance to ampicillin, sulphanilamide and multiple (greater than or equal to3) antibiotics than Cu-sensitive Gram-negative isolates. Furthermore, Cu-resistant Gram-negative isolates from Cu-contaminated plots had significantly higher incidence of resistance...

  14. Bacterial Contamination and Antibiotic Resistance of Staphylococcus Aureus Isolated from Automated Teller Machine

    Directory of Open Access Journals (Sweden)

    Moshtaghi, H. (PhD

    2015-05-01

    Full Text Available Background and Objective: Automated Teller Machine (ATMs is likely to be contaminated with various microorganisms specially pathogen germs. This may be due to their exposure to dust and their vast dermal contact with multiple users. This study investigated the bacterial contamination on the keyboard of ATMs and drug resistance of the bacteria isolated from them. Material and Methods: the keyboards of 50 ATMs in Shahrekord city, Iran, were examined from October 2012 to February 2013. The sterile swab sticks moistened with Triptose soy broth were used for sampling. The bacteriological tests used were culture, biochemical test and agar disk diffusion method for antibiogram. Results: All the samples were found to be contaminated with Coagulase negative staphylococci (57.54%, Bacillus species (21.92%, Staphylococcus aureus (19.18% and coliform bacteria (1.36%. The resistance of Staphylococcus aureus was 92.8% to penicillin, 85.7% to amoxicilin، 71.4% to ampicillin, 57.1% to nytrofuran, 50% to tetracycline, 42.8% to erythromycin, 42.8% to gentamycin, 14.2 % to ciprofloxacin, 7.1% to trimethoprim and sulfamtuksazul. All species were susceptible to, ofloxacine, chloramphenicol, clindamycin, tobramycin, vancomycin and cefotaxime. Conclusion: given the presence of pathogens on ATMs and their role in transferring the contamination, we recommend considering personal hygiene and periodically disinfecting the keyboards to reduce contamination

  15. [Surveillance reports on pathogens and their antibiotic resistance patterns - a recommendation for standardization].

    Science.gov (United States)

    Warnke, P; Aepfelbacher, M; Fickenscher, H; Solbach, W; Steinmetz, I; Podbielski, A

    2014-06-01

    Surveillance reports on infectious agents and their antibiotic resistance patterns as well as on the usage of antibiotics are now enforced by law for many medical institutions in Germany. However, specific practice-oriented recommendations concerning the appropriate extent and informative mode of presentation are lacking. This consensus statement resulted from the experience from five German university hospitals in handling data from infection epidemiology and in the various possibilities for the presentation of surveillance reports. The consensus statement provides recommendations for the preparation of the legally demanded surveillance reports, extending the existing regulations. The relevance of statements on frequency and quality of microbiological tests is included. Furthermore, modes for the standardization of the data analysis are suggested in order to achieve a regional and national comparability of the results on a high quality level, similarly to the established standardized surveillance of nosocomial infections. This consensus statement describes the form in which the legally enforced reports can be presented in an informative and standardized way in order to facilitate the deduction and realization of preventive measurements.

  16. Sludge as a potential important source of antibiotic resistance genes in both the bacterial and bacteriophage fractions.

    Science.gov (United States)

    Calero-Cáceres, William; Melgarejo, Ana; Colomer-Lluch, Marta; Stoll, Claudia; Lucena, Francisco; Jofre, Juan; Muniesa, Maite

    2014-07-01

    The emergence and prevalence of antibiotic resistance genes (ARGs) in the environment is a serious global health concern. ARGs found in bacteria can become mobilized in bacteriophage particles in the environment. Sludge derived from secondary treatment in wastewater treatment plants (WWTPs) constitutes a concentrated pool of bacteria and phages that are removed during the treatment process. This study evaluates the prevalence of ARGs in the bacterial and phage fractions of anaerobic digested sludge; five ARGs (blaTEM, blaCTX-M, qnrA, qnrS, and sul1) are quantified by qPCR. Comparison between the wastewater and sludge revealed a shift in the prevalence of ARGs (blaTEM and sul1 became more prevalent in sludge), suggesting there is a change in the bacterial and phage populations from wastewater to those selected during the secondary treatment and the later anaerobic mesophilic digestion of the sludge. ARGs densities were higher in the bacterial than in the phage fraction, with high densities in both fractions; particularly for blaTEM and sul1 (5 and 8 log10 gene copies (GC)/g, respectively, in bacterial DNA; 5.5 and 4.4 log10 GC/g, respectively, in phage DNA). These results question the potential agricultural uses of treated sludge, as it could contribute to the spread of ARGs in the environment and have an impact on the bacterial communities of the receiving ecosystem.

  17. Aerobic bacterial profile and antibiotic resistance in patients with diabetic foot infections

    Directory of Open Access Journals (Sweden)

    Michele Cezimbra Perim

    2015-10-01

    Full Text Available ABSTRACTINTRODUCTION: This study aimed to determine the frequencies of bacterial isolates cultured from diabetic foot infections and assess their resistance and susceptibility to commonly used antibiotics.METHODS: This prospective study included 41 patients with diabetic foot lesions. Bacteria were isolated from foot lesions, and their antibiotic susceptibility pattern was determined using the Kirby-Bauer disk diffusion method and/or broth method [minimum inhibitory concentration (MIC].RESULTS: The most common location of ulceration was the toe (54%, followed by the plantar surface (27% and dorsal portion (19%. A total of 89 bacterial isolates were obtained from 30 patients. The infections were predominantly due to Gram-positive bacteria and polymicrobial bacteremia. The most commonly isolated Gram-positive bacteria were Staphylococcus aureus, followed by Staphylococcus saprophyticus, Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus pneumoniae. The most commonly isolated Gram-negative bacteria were Proteus spp. and Enterobacterspp., followed by Escherichia coli, Pseudomonasspp., and Citrobacterspp. Nine cases of methicillin-resistant Staphylococcus aureus (MRSA had cefoxitin resistance, and among these MRSA isolates, 3 were resistant to vancomycin with the MIC technique. The antibiotic imipenem was the most effective against both Gram-positive and Gram-negative bacteria, and gentamicin was effective against Gram-negative bacteria.CONCLUSIONS: The present study confirmed the high prevalence of multidrug-resistant pathogens in diabetic foot ulcers. It is necessary to evaluate the different microorganisms infecting the wound and to know the antibiotic susceptibility patterns of the isolates from the infected wound. This knowledge is crucial for planning treatment with the appropriate antibiotics, reducing resistance patterns, and minimizing healthcare costs.

  18. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Hansen, Malene Plejdrup; Hoffmann, Tammy C; McCullough, Amanda R

    2015-01-01

    Numerous opportunities are available in primary care for alleviating the crisis of increasing antibiotic resistance. Preventing patients from developing an acute respiratory infection (ARI) will obviate any need for antibiotic use downstream. Hygiene measures such as physical barriers and hand...... wrong. Shared decision making might be a solution, as it enables clinician and patient to participate jointly in making a health decision, having discussed the options together with the evidence for their harms as well as benefits. Furthermore, GPs' diagnostic uncertainty - often leading...... will greatly improve the use of antibiotics for ARIs. However, used in concert, combinations are likely to enable clinicians and health care systems to implement the strategies that will reduce antimicrobial resistance in the future....

  19. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Munck, Christian

    morbidity and mortality as well as an increase in the cost of treatment. Understanding how bacteria respond to antibiotic exposure gives the foundations for a rational approach to counteract antimicrobial resistance. In the work presented in this thesis, I explore the two fundamental sources...... of antimicrobial resistance: (1) adaptive mutations and (2) horizontal acquisition of resistance genes from antibiotic gene reservoirs. By studying the geno- and phenotypic changes of E. coli in response to single and drug-pair exposures, I uncover the evolutionary trajectories leading to adaptive resistance. I...... to rationally design drug combinations that limit the evolution of antibiotic resistance due to counteracting evolutionary trajectories. My results highlight that an in-depth knowledge about the genetic responses to the individual antimicrobial compounds enables the prediction of responses to drug combinations...

  20. High level multiple antibiotic resistance among fish surface associated bacterial populations in non-aquaculture freshwater environment.

    Science.gov (United States)

    Ozaktas, Tugba; Taskin, Bilgin; Gozen, Ayse G

    2012-12-01

    Freshwater fish, Alburnus alburnus (bleak), were captured from Lake Mogan, situated in Ankara, during spring. The surface mucus of the fish was collected and associated bacteria were cultured and isolated. By sequencing PCR-amplified 16S RNA encoding genes, the isolates were identified as members of 12 different genera: Acinetobacter, Aeromonas, Bacillus, Brevundimonas, Gordonia, Kocuria, Microbacterium, Mycobacterium, Pseudomonas, Rhodococcus, and Staphylococcus, in addition to one strain that was unidentified. The mucus-dwelling bacterial isolates were tested for resistance against ampicillin, kanamycin, streptomycin and chloramphenicol. About 95% of the isolates were found to be resistant to ampicillin, 93% to chloramphenicol, and 88% to kanamycin and streptomycin. A Microbacterium oxydans and the unidentified environmental isolate were resistant to all four antibiotics tested at very high levels (>1600 μg/ml ampicillin and streptomycin; >1120 μg/ml kanamycin; >960 μg/ml chloramphenicol). Only a Kocuria sp. was sensitive to all four antibiotics at the lowest concentrations tested (3.10 μg/ml ampicillin and streptomycin; 2.15 μg/ml kanamycin; 1.85 μg/ml chloramphenicol). The rest of the isolates showed different resistance levels. Plasmid isolations were carried out to determine if the multiple antibiotic resistance could be attributed to the presence of plasmids. However, no plasmid was detected in any of the isolates. The resistance appeared to be mediated by chromosome-associated functions. This study indicated that multiple antibiotic resistance at moderate to high levels is common among the current phenotypes of the fish mucus-dwelling bacterial populations in this temperate, shallow lake which has not been subjected to any aquaculturing so far but under anthropogenic effect being in a recreational area.

  1. Infectious prosthetic hip joint loosening: bacterial species involved in its aetiology and their antibiotic resistance profiles against antibiotics recommended for the therapy of implant-associated infections.

    Science.gov (United States)

    Bogut, Agnieszka; Niedźwiadek, Justyna; Strzelec-Nowak, Dagmara; Blacha, Jan; Mazurkiewicz, Tomasz; Marczyński, Wojciech; Kozioł-Montewka, Maria

    2014-04-01

    Reliable microbiological diagnosis along with surgery and prolonged antibiotic therapy are key elements in the management of prosthetic-joint infections (PJIs). The purpose of this study was to characterize antibiotic resistance profiles of bacteria involved in the aetiology of PJIs. A total of 33 bacterial isolates cultured from 31 patients undergoing exchange of total hip prostheses were analyzed. The diagnostic approach toward isolation of prosthesis- associated microorganisms included sonication of retrieved implants and conventional cultures of periprosthetic tissues and synovial fluid. The in vitro resistance profiles of bacterial isolates were determined in relation to antibiotics recommended for the therapy of PJIs using the disc diffusion method, E-tests(®) and broth microdilution system. Coagulase-negative staphylococci (CNS) were predominant microorganisms followed by Staphylococcus aureus, Enterobacter cloacae, Streptococcus mitis, and Propionibacterium acnes. Twenty out of 30 and 12 out of 30 staphylococcal isolates were methicillin- and multi-drug resistant, respectively. Only two isolates were rifampicinresistant. All staphylococci were susceptible to glycopeptides and linezolid. This paper stresses the pathogenic role of staphylococci in patients suffering from implant loosening and reports high methicillin- and multidrug-resistance rates in these bacteria. Hence, antimicrobial susceptibility tests of individual bacterial isolates must always be performed to guide selection of the optimal therapeutic option.

  2. [Biotypes and antibiotic resistance patterns of Gardnerella vaginalis strains isolated from healthy women and women with bacterial vaginosis].

    Science.gov (United States)

    Tosun, Ilknur; Alpay Karaoğlu, Sengül; Ciftçi, Hasan; Buruk, Celal Kurtuluş; Aydin, Faruk; Kiliç, Ali Osman; Ertürk, Murat

    2007-01-01

    As Gardnerella vaginalis is accepted as a member of normal vaginal flora, it is one of the dominant species which has been related to bacterial vaginosis (BV). The aim of this study was to determine the isolation rate, biotypes and antibiotic resistance patterns of G.vaginalis from the vaginal swab samples of 408 women who were admitted to the outpatient clinics of Family Planning Center. Hippurate hydrolysis, lipase and beta-galactosidase tests were performed for biotyping the isolates, and agar dilution (for metronidazole) and disk diffusion (for clindamycin) tests were used for the detection of antibiotic resistance patterns. As a result, by Nugent's BV scoring protocol, 122 (29.9%), 20 (29.4%), 137 (33.6%), and 18 (4.4%) of the women were diagnosed as BV, intermediate form, normal vaginal flora (NVF) and mycotic vaginosis, respectively. The overall isolation rate of G.vaginalis was found as 23% (94/408). Of them, 56.4% (53/94) and 8.5% (8/94) were isolated from samples of BV cases and subjects with NVF, respectively, and the difference was statistically significant (pbiotyping results showed that the most frequently detected types were biotype 1 (44%), 5 (20%) and 4 (18%). There was no statistically significant difference between the biotype distribution of BV patients and the subjects who have NVF (p=0.687). The results of antibiotic susceptibility tests indicated that 70% and 53% of the isolates were resistant to metronidazole and clindamycin, respectively. It was of interest that MIC values for metronidazole was > or =128 microg/ml in 57% of resistant strains. The data of this study has emphasized that the metronidazole resistance is very high in our population, and the large scale studies are needed to clarify the relationship between BV and G.vaginalis biotypes, which can be found in the normal vaginal flora.

  3. Streaming algorithms for identification of pathogens and antibiotic resistance potential from real-time MinION(TM) sequencing.

    Science.gov (United States)

    Cao, Minh Duc; Ganesamoorthy, Devika; Elliott, Alysha G; Zhang, Huihui; Cooper, Matthew A; Coin, Lachlan J M

    2016-07-26

    The recently introduced Oxford Nanopore MinION platform generates DNA sequence data in real-time. This has great potential to shorten the sample-to-results time and is likely to have benefits such as rapid diagnosis of bacterial infection and identification of drug resistance. However, there are few tools available for streaming analysis of real-time sequencing data. Here, we present a framework for streaming analysis of MinION real-time sequence data, together with probabilistic streaming algorithms for species typing, strain typing and antibiotic resistance profile identification. Using four culture isolate samples, as well as a mixed-species sample, we demonstrate that bacterial species and strain information can be obtained within 30 min of sequencing and using about 500 reads, initial drug-resistance profiles within two hours, and complete resistance profiles within 10 h. While strain identification with multi-locus sequence typing required more than 15x coverage to generate confident assignments, our novel gene-presence typing could detect the presence of a known strain with 0.5x coverage. We also show that our pipeline can process over 100 times more data than the current throughput of the MinION on a desktop computer.

  4. Occurrence and reservoirs of antibiotic resistance genes in the environment

    NARCIS (Netherlands)

    Seveno, N.; Kallifidas, D.; Smalla, K.; Elsas, van J.D.; Collard, J.M.; Karagouni, A.; Wellington, E.M.H.

    2002-01-01

    Antibiotic resistance genes have become highly mobile since the development of antibiotic chemotherapy. A considerable body of evidence exists proving the link between antibiotic use and the significant increase in drug-resistant human bacterial pathogens. The application of molecular detection and

  5. Antibiotic resistance in human peri-implantitis microbiota

    NARCIS (Netherlands)

    Rams, Thomas E.; Degener, John E.; van Winkelhoff, Arie J.

    2014-01-01

    ObjectivesBecause antimicrobial therapy is often employed in the treatment of infectious dental implant complications, this study determined the occurrence of in vitro antibiotic resistance among putative peri-implantitis bacterial pathogens. MethodsSubmucosal biofilm specimens were cultured from 16

  6. A framework for global surveillance of antibiotic resistance

    NARCIS (Netherlands)

    Grundmann, Hajo; Klugman, Keith P.; Walsh, Timothy; Ramon-Pardo, Pilar; Sigauque, Betuel; Khan, Wasif; Laxminarayan, Ramanan; Heddini, Andreas; Stelling, John

    2011-01-01

    The foreseen decline in antibiotic effectiveness explains the needs for data to inform the global public health agenda about the magnitude and evolution of antibiotic resistance as a serious threat to human health and development. Opportunistic bacterial pathogens are the cause of the majority of co

  7. Bacterial flora and antibiotic resistance from eggs of green turtles Chelonia mydas: an indication of polluted effluents.

    Science.gov (United States)

    Al-Bahry, Saif; Mahmoud, Ibrahim; Elshafie, Abdulkader; Al-Harthy, Asila; Al-Ghafri, Sabha; Al-Amri, Issa; Alkindi, Abdulaziz

    2009-05-01

    Sea turtles migrate to various habitats where they can be exposed to different pollutants. Bacteria were collected from turtle eggs and their resistance to antibiotics was used as pollutant bio-indicators of contaminated effluents. Eggs were collected randomly from turtles when they were laying their eggs. A total of 90 eggs were collected and placed into sterile plastic bags (3 eggs/turtle) during June-December of 2003. The bacteria located in the eggshell, albumen and yolk were examined, and 42% of the eggs were contaminated with 10 genera of bacteria. Pseudomonas spp. were the most frequent isolates. The albumen was found to be the part of the egg to be the least contaminated by bacterial infection. Bacterial isolates tested with 14 antibiotics showed variations in resistance. Resistance to ampicillin was the highest. The presence of antibiotic resistant bacteria in eggs indicates that the green turtle populations were subjected to polluted effluents during some of their migratory routes and feeding habitats. Scanning electron microscopy revealed that Salmonella typhimurium penetrated all eggshell layers.

  8. Bacteriophage biosensors for antibiotic-resistant bacteria.

    Science.gov (United States)

    Sorokulova, Irina; Olsen, Eric; Vodyanoy, Vitaly

    2014-03-01

    An increasing number of disease-causing bacteria are resistant to one or more anti-bacterial drugs utilized for therapy. Early and speedy detection of these pathogens is therefore very important. Traditional pathogen detection techniques, that include microbiological and biochemical assays are long and labor-intensive, while antibody or DNA-based methods require substantial sample preparation and purification. Biosensors based on bacteriophages have demonstrated remarkable potential to surmount these restrictions and to offer rapid, efficient and sensitive detection technique for antibiotic-resistant bacteria.

  9. Microbial Indicators, Pathogens, and Antibiotic Resistance in Groundwater Impacted by Animal Farming: Field Scale to Basin Scale

    Science.gov (United States)

    Harter, T.; Li, X.; Atwill, E. R.; Packman, A. I.

    2015-12-01

    Several surveys of microbial indicators and pathogens were conducted to determine the impact of confined animal farming operations (CAFOs) on shallow, local, and regional groundwater quality in the Central Valley aquifer system, California. The aquifer system consists of highly heterogeneous, alluvial, unconsolidated coarse- to fine-grained sediments and is among the largest aquifers in the U.S.. Overlying landuse includes 3 million ha of irrigated agriculture and 1.7 million mature dairy cows in nearly 1,500 CAFOs. A multi-scale survey of water-borne indicator pathogens (Enterococcus spp. and generic E. coli) and of three water-borne pathogens (Campylobacter, Salmonella, and E. coli O157:H7) was conducted at five different spatial scales, increasing with distance from animal sources of these enteric microbial organisms: moist surfaces within individual CAFO sub-systems (calf-hutches, heifer corrals, mature cow stalls, hospital barn etc.), first encountered (shallow) groundwater immediately below these sub-systems, production aquifer below CAFOs, production aquifer near CAFOs, and production aquifer away from CAFOs. Where found, indicator pathogens were tested for antibiotic resistance. Hundreds of samples were collected at each scale: continuously during irrigation events and seasonally over a multi-year period at the three smaller site-scales; and in a one-time survey at the two larger, regional scales. All three pathogens were frequently detected in moist surface samples across CAFO sub-systems, albeit at concentrations several orders of magnitude lower than enteric indicators. Two of the three pathogens (but not Campylobacter) were also detected in first encountered groundwater, at 3-9 m below ground surface, in 1% of samples. No pathogens were found at the production aquifer scales. Generic E. coli was detected in ¼ of first encountered groundwater samples, and in 4% of production aquifer samples, while Enterococcus spp. was ubiquitously present across the

  10. Facts about Antibiotic Resistance

    Science.gov (United States)

    ... Cost References Español: Datos breves Facts about Antibiotic Resistance Antibiotic resistance is one of the world’s most pressing public ... antibiotic use is a key strategy to control antibiotic resistance. Antibiotic resistance in children and older adults are ...

  11. [Bacterial efflux pumps - their role in antibiotic resistance and potential inhibitors].

    Science.gov (United States)

    Hricová, Kristýna; Kolář, Milan

    2014-12-01

    Efflux pumps capable of actively draining antibiotic agents from bacterial cells may be considered one of potential mechanisms of the development of antimicrobial resistance. The most important group of efflux pumps capable of removing several types of antibiotics include RND (resistance - nodulation - division) pumps. These are three proteins that cross the bacterial cell wall, allowing direct expulsion of the agent out from the bacterial cell. The most investigated efflux pumps are the AcrAB-TolC system in Escherichia coli and the MexAB-OprM system in Pseudomonas aeruginosa. Moreover, efflux pumps are able to export other than antibacterial agents such as disinfectants, thus decreasing their effectiveness. One potential approach to inactivation of an efflux pump is to use the so-called efflux pump inhibitors (EPIs). Potential inhibitors tested in vitro involve, for example, phenylalanyl-arginyl-b-naphthylamide (PAbN), carbonyl cyanide m-chlorophenylhydrazone (CCCP) or agents of the phenothiazine class.

  12. Antibiotic resistance & pathogen profile in ventilator-associated pneumonia in a tertiary care hospital in India

    Directory of Open Access Journals (Sweden)

    Abhijit Chaudhury

    2016-01-01

    Results: VAP rates of 44.1, 43.8 and 26.3 were seen in 2011, 2012 and 2013, respectively. In all the three years, non-fermentative Gram-negative bacilli were the predominant organisms, followed by Pseudomonas spp. and Klebsiella spp. Staphylococcus aureus exhibited a downwards trend in prevalence from 50.0 per cent in 2011 to 34.9 per cent in 2013. An increase in vancomycin-resistant enterococci was seen from 4.3 per cent in 2012 to 8.3 per cent in 2013, while methicillin resistance amongst the S. aureus crossed the 50 per cent mark in 2013. An increasing trend in resistance was shown by Pseudomonas spp. for piperacillin-tazobactam (PTZ, amikacin and imipenem (IPM. For the non-fermenters, resistance frequency remained very high except for IPM (33.1% and polymyxin-B (2.4%. Interpretation & conclusions: Our findings show VAP as an important problem in the ICU setting. The incidence of multidrug-resistant pathogens was on the rise. The resistance pattern of these pathogens can help an institution to formulate effective antimicrobial policy. To have a comprehensive pan-India picture, multicentric studies are needed.

  13. EcAMSat: Effect of Space-Flight on Antibiotic Resistance of a Pathogenic Bacterium and its Genetic Basis

    Science.gov (United States)

    Matin, A. C.; Benoit, M.; Chin. M.; Chinn, T. N.; Cohen, A.; Friedericks, C.; Henschke, M. B.; Keyhan, M.; Lera, M. P.; Padgen, M. R.; Parra, M. P.; Ricco, A. J.; Singh, R.; Snyder, T.; Spremo, S. M.; Wang, J.

    2015-01-01

    Human immune response is compromised in space and incidence of urinary tract infections (UTI) in astronauts has been reported. We have found that the causative agent of UTI, the uropathogenic Escherichia coli, becomes more resistant to gentamicin (Gm), which is commonly used to treat this disease, under modeled microgravity conditions (MMG), the increase being controlled by the stress response master regulator, ss. While the wild type bacterium becomes virtually invincible under MMG, the strain missing this sigma factor barely survives. We report here preparatory ground work for testing this finding in space flight on a nanosatellite. We have shown that the effect of Gm treatment on culture viability is directly correlated to increased Alamar Blue (AB) reduction; we have identified conditions to keep the experimental elements - the bacterial cultures, Gm, and AB - in a state of viability and potency to permit successful spaceflight experimentation given the necessary constraints. Spaceflight kinetics of AB reduction will be transmitted from the satellite via telemetry. The PharmaSat hardware previously used for space experimentation with yeast was modified to permit studies with bacteria by reducing the filter pore size and increasing fluidics volume to enable more fluid exchanges. Several verification tests have been run using the nanosatellite's flight software and prototype hardware. Cells were grown to stationary phase to induce the ss-controlled stress resistance and treated with Gm. Without Gm, the mutant took longer than the wild type to reduce the AB; this time difference increased almost 8 fold at 55 µg/mL Gm concentration. Thus, using flight hardware the mutant shows similarly increased sensitivity to Gm compared to the wild type to that found in our pilot microtiter plate experiments. Previous inflight experiments have given contradictory results concerning bacterial antibiotic resistance; none has yet explored the involvement of specific genes in this

  14. Bacterial urinary tract infection in renal transplant recipients and their antibiotic resistance pattern: A four-year study.

    Directory of Open Access Journals (Sweden)

    Azar Dokht Khosravi

    2014-04-01

    Full Text Available Urinary tract infections (UTIs are the most common infections in renal transplant recipients and are considered a potential cause of bacteremia, sepsis, and affects graft outcomes. The aim of the present study was to determine the incidence of UTI among renal transplant recipients and investigation of antimicrobial susceptibility pattern of causative agents.In total, 1165 patients from March 2009 to December 2012, in transplant center of Golestan Hospital, Ahvaz, Iran, were investigated. Qualitative urine cultures were performed for all cases, causative microorganisms were identified and colony count was performed according to the standard protocol. Antibiotic susceptibility testing was then performed to determine the susceptibility pattern of recovered bacteria from confirmed UTIs.UTI was diagnosed in 391 patients(33.56%. Gram-negative bacteria were the most prevalent isolated microorganisms with E. coli (43.53%, followed by Enterobacter spp. (35.37% as the major organisms. Among Gram positives, Coagulase-negative Staphylococci was isolated from 6.8% of cases. The rate of resistance to all tested antibiotics was highest in Enterobacter spp., however the most common resistance were seen against cefixime, cephalotin, and cotrimoxazole in all tested gram negatives.the rate of UTIs among renal transplant recipients was noticeable in this study with high antibiotic resistance. Multi-resistant bacterial infections are potentially life-threatening emerging problem in renal transplantation. Prophylactic measures must be applied to patients at greater risk.

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

    Science.gov (United States)

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

    2015-05-01

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

  16. Molecular design and genetic optimization of antimicrobial peptides containing unnatural amino acids against antibiotic-resistant bacterial infections.

    Science.gov (United States)

    He, Yongkang; He, Xiaofeng

    2016-09-01

    Antimicrobial peptides (AMPs) have been the focus of intense research towards the finding of a viable alternative to current small-molecule antibiotics, owing to their commonly observed and naturally occurring resistance against pathogens. However, natural peptides have many problems such as low bioavailability and high allergenicity that largely limit the clinical applications of AMPs. In the present study, an integrative protocol that combined chemoinformatics modeling, molecular dynamics simulations, and in vitro susceptibility test was described to design AMPs containing unnatural amino acids (AMP-UAAs). To fulfill this, a large panel of synthetic AMPs with determined activity was collected and used to perform quantitative structure-activity relationship (QSAR) modeling. The obtained QSAR predictors were then employed to direct genetic algorithm (GA)-based optimization of AMP-UAA population, to which a number of commercially available, structurally diverse unnatural amino acids were introduced during the optimization process. Subsequently, several designed AMP-UAAs were confirmed to have high antibacterial potency against two antibiotic-resistant strains, i.e. multidrug-resistant Pseudomonas aeruginosa (MDRPA) and methicillin-resistant Staphylococcus aureus (MRSA), with minimum inhibitory concentration (MIC) < 10 μg/ml. Structural dynamics characterizations revealed that the most potent AMP-UAA peptide is an amphipathic helix that can spontaneously embed into an artificial lipid bilayer and exhibits a strong destructuring tendency associated with the embedding process. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 746-756, 2016.

  17. Bacterial Communities and Antibiotic Resistance Communities in a Full-Scale Hospital Wastewater Treatment Plant by High-Throughput Pyrosequencing

    Directory of Open Access Journals (Sweden)

    Youngho Ahn

    2016-12-01

    Full Text Available The community of whole microbes and antibiotic resistance bacteria (ARB in hospital wastewater treatment plants (WWTP receiving domestic wastewater (DWW and hospital wastewater (HWW was investigated. Samples from an influent of a secondary clarifier, at each treatment train, were characterized for the whole microbial community and ARB on the antibiotic resistance database, based on high-throughput pyrosequencing. The pyrosequencing analysis revealed that the abundance of Bacteroidetes in the DWW sample was higher (~1.6 times than in the HWW sample, whereas the abundance of Proteobacteria in the HWW sample was greater than in the DWW sample. At the top twenty of the genus level, distinct genera were observed—Saprospiraceae in the DWW and Zoogloea in the HWW. Apart from the top twenty genera, minor genera showed various antibiotic resistance types based on the antibiotic resistance gene database.

  18. Comparison of the incidence of pathogenic and antibiotic-resistant Escherichia coli strains in adult cattle and veal calf slaughterhouse effluents highlighted different risks for public health.

    Science.gov (United States)

    Um, Maryse Michèle; Barraud, Olivier; Kérourédan, Monique; Gaschet, Margaux; Stalder, Thibault; Oswald, Eric; Dagot, Christophe; Ploy, Marie-Cecile; Brugère, Hubert; Bibbal, Delphine

    2016-01-01

    The goal of this study was to investigate the involvement of bovine slaughterhouse effluents and biosolids in the risk of environmental dissemination of pathogenic and antibiotic-resistant Escherichia coli. Several samples were collected from one adult cattle and one veal calf slaughterhouse wastewater treatment plant (WWTP). The treatment process had no impact on the percentage of Shiga toxin-producing E. coli (STEC) and on the percentage of atypical enteropathogenic E. coli (aEPEC). A STEC O157:H7 was isolated from the thickened sludge of the adult cattle slaughterhouse. As thickened sludge is intended to be spread on agricultural lands, the detection of this pathogenic strain is a public health issue. The percentage of antibiotic-resistant E. coli was 5.0% and 87.5% in wastewater from the adult cattle and the veal calf slaughterhouse, respectively. These percentages were not significantly different after treatment. Integron-bearing E. coli isolates were only detected in the veal calf slaughterhouse WWTP with percentages above 50.0% for all sampling points whatever the step of the treatment process. Taken together, these findings highlighted the fact that different public health risks might be associated with adult cattle or veal calf slaughterhouses regarding the dissemination of pathogenic and antibiotic-resistant E. coli isolates into the environment.

  19. Structural Studies of Bacterial Enzymes and their Relation to Antibiotic Resistance Mechanisms - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β- lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes

  20. Comparison of antibiotic resistance of bacterial agents associated in septicaemia in children and infants

    Directory of Open Access Journals (Sweden)

    Mohammad Kazem Sharifi Yazdi

    2014-05-01

    Full Text Available Background: Septicaemia is a leading cause of morbidity and mortality of infant’s and childerens espicially in first week of their life, both in developed and underdeveloped countries.The aim of this research was to study of bacterial agents causing septicaemia and to determine their antibiotic suseptibility patternes. Materials and Methods : This was a descriptive study, it was performed during eight months from October 2011 till May 2011.In total 216 blood culture samples of children suspected of septicaemia in children health centre hospital were send to the laboratory for investigation. The bacterial identification was carried out by culturing and conventional biomedical tests. The antibiotic sensitivity tests were performed by disk diffusion method. These data are analyzed by SPSS and the results Expressed as relative frequencies. Results: Out of 216 tested samples 55(25.6% were positive and 161 (74.54% negative. The dominated bacteria was Escherichia coli (31.42%, followed by Staphylococcus aureus (22.86 %, Klebsiella pneumonia (20%, Staphylococcus epidermidis (14.28%, Streptococcus pneumonia (2.86%, Salmonella typhi (2.86%, Enterobacter cloacae (2.86% and Stenotrophomonas maltophilia (2.86%. In general gram-negative bacteria were isolated more than gram-positive. Staphylococcus bacteria were more resistant to antibiotics than other isolated bacteria, and were 100% resistant to penicillin. The enterobacteriaceae were more sensitive to norfloxacin, amikacin, tobramycin, and they were 100% resistant to ampicillin. Conclusion: The results obtained in this study showed that gram-negative bacteria are more responsible in septicaemia in children ward, and norfloxacin is the more effective antibiotic in comparison with others.

  1. Plasmid interference for curing antibiotic resistance plasmids in vivo

    Science.gov (United States)

    Kamruzzaman, Muhammad; Shoma, Shereen; Thomas, Christopher M.; Partridge, Sally R.

    2017-01-01

    Antibiotic resistance increases the likelihood of death from infection by common pathogens such as Escherichia coli and Klebsiella pneumoniae in developed and developing countries alike. Most important modern antibiotic resistance genes spread between such species on self-transmissible (conjugative) plasmids. These plasmids are traditionally grouped on the basis of replicon incompatibility (Inc), which prevents coexistence of related plasmids in the same cell. These plasmids also use post-segregational killing (‘addiction’) systems, which poison any bacterial cells that lose the addictive plasmid, to guarantee their own survival. This study demonstrates that plasmid incompatibilities and addiction systems can be exploited to achieve the safe and complete eradication of antibiotic resistance from bacteria in vitro and in the mouse gut. Conjugative ‘interference plasmids’ were constructed by specifically deleting toxin and antibiotic resistance genes from target plasmids. These interference plasmids efficiently cured the corresponding antibiotic resistant target plasmid from different Enterobacteriaceae in vitro and restored antibiotic susceptibility in vivo to all bacterial populations into which plasmid-mediated resistance had spread. This approach might allow eradication of emergent or established populations of resistance plasmids in individuals at risk of severe sepsis, enabling subsequent use of less toxic and/or more effective antibiotics than would otherwise be possible, if sepsis develops. The generalisability of this approach and its potential applications in bioremediation of animal and environmental microbiomes should now be systematically explored. PMID:28245276

  2. Mobile antibiotic resistance - the spread of genes determining the resistance of bacteria through food products.

    Science.gov (United States)

    Godziszewska, Jolanta; Guzek, Dominika; Głąbski, Krzysztof; Wierzbicka, Agnieszka

    2016-07-07

    In recent years, more and more antibiotics have become ineffective in the treatment of bacterial nfections. The acquisition of antibiotic resistance by bacteria is associated with circulation of genes in the environment. Determinants of antibiotic resistance may be transferred to pathogenic bacteria. It has been shown that conjugation is one of the key mechanisms responsible for spread of antibiotic resistance genes, which is highly efficient and allows the barrier to restrictions and modifications to be avoided. Some conjugative modules enable the transfer of plasmids even between phylogenetically distant bacterial species. Many scientific reports indicate that food is one of the main reservoirs of these genes. Antibiotic resistance genes have been identified in meat products, milk, fruits and vegetables. The reason for such a wide spread of antibiotic resistance genes is the overuse of antibiotics by breeders of plants and animals, as well as by horizontal gene transfer. It was shown, that resistance determinants located on mobile genetic elements, which are isolated from food products, can easily be transferred to another niche. The antibiotic resistance genes have been in the environment for 30 000 years. Their removal from food products is not possible, but the risks associated with the emergence of multiresistant pathogenic strains are very large. The only option is to control the emergence, selection and spread of these genes. Therefore measures are sought to prevent horizontal transfer of genes. Promising concepts involve the combination of developmental biology, evolution and ecology in the fight against the spread of antibiotic resistance.

  3. Antibiotic resistance pattern of bacterial isolates from cases of urinary tract infections among hospitalized and out-patients at a tertiary health facility in South Western Nigeria

    Directory of Open Access Journals (Sweden)

    Oyekale Oluwalana Timothy

    2014-01-01

    Full Text Available Aim: Urinary tract infections (UTIs are among the most common human infections with distribution of causative agents and their susceptibility pattern to antibiotics varying from region to region. This study aimed at determining the bacterial uropathogens and their antibiotic resistance profile among patients in a Nigerian tertiary health care facility. Materials and Methods: Appropriate urine specimens (midstream/catheter specimen urine of all suspected cases of UTI by clinicians were processed in the medical microbiology laboratory for detection of significant bacteriuria. Bacteria uropathogens isolated were identified by standard biochemical tests and antibiotic susceptibility test to eight antibiotics was carried out on them using Kirby-Bauer disc diffusion technique. Methicillin-resistant Staphylococcus aureus (MRSA was identified by cefoxitin disc diffusion technique and extended-spectrum beta-lactamase (ESBL producing enterobacteria were detected using double-disc synergy test. Results: Of the total 157 males and 189 females investigated, 35.7% and 66.1% respectively had significant bacteriuria. Escherichia coli was the most commonly isolated bacterial pathogen both among in- and out-patients (52.6% vs. 65.5%. Other isolated organisms were S. aureus (13.4% vs. 19.0%, Pseudomonas aeruginosa (10.3% vs. 2.4%, Klebsiella pneumoniae (7.2% vs. 7.1% and K. aerogenes (7.2% vs. 1.2%. Resistance rate of uropathogens to antibiotics was higher among in-patients. Resistance rate to ofloxacin, ceftazidime and ceftriaxone was generally very low compared to other tested antibiotics. Multiple resistant bacteria: MRSA and ESBL-producing enterobacteria were detected among both in-and out-patient with no significant difference in isolation rate. Conclusion: There is a need for continuous monitoring of uropathogens and their antibiotic sensitivity profile for evidence-based empirical treatment of UTI. There is an urgent need for the establishment of antibiotic

  4. A locked nucleic acid (LNA-based real-time PCR assay for the rapid detection of multiple bacterial antibiotic resistance genes directly from positive blood culture.

    Directory of Open Access Journals (Sweden)

    Lingxiang Zhu

    Full Text Available Bacterial strains resistant to various antibiotic drugs are frequently encountered in clinical infections, and the rapid identification of drug-resistant strains is highly essential for clinical treatment. We developed a locked nucleic acid (LNA-based quantitative real-time PCR (LNA-qPCR method for the rapid detection of 13 antibiotic resistance genes and successfully used it to distinguish drug-resistant bacterial strains from positive blood culture samples. A sequence-specific primer-probe set was designed, and the specificity of the assays was assessed using 27 ATCC bacterial strains and 77 negative blood culture samples. No cross-reaction was identified among bacterial strains and in negative samples, indicating 100% specificity. The sensitivity of the assays was determined by spiking each bacterial strain into negative blood samples, and the detection limit was 1-10 colony forming units (CFU per reaction. The LNA-qPCR assays were first applied to 72 clinical bacterial isolates for the identification of known drug resistance genes, and the results were verified by the direct sequencing of PCR products. Finally, the LNA-qPCR assays were used for the detection in 47 positive blood culture samples, 19 of which (40.4% were positive for antibiotic resistance genes, showing 91.5% consistency with phenotypic susceptibility results. In conclusion, LNA-qPCR is a reliable method for the rapid detection of bacterial antibiotic resistance genes and can be used as a supplement to phenotypic susceptibility testing for the early detection of antimicrobial resistance to allow the selection of appropriate antimicrobial treatment and to prevent the spread of resistant isolates.

  5. Emerging antibiotic resistance in bacteria with special reference to India.

    Science.gov (United States)

    Raghunath, D

    2008-11-01

    The antibiotic era started in the 1940s and changed the profile of infectious diseases and human demography. The burgeoning classes and numbers promised much and elimination of this major cause of human (and animal) morbidity appeared possible. Bacterial antibiotic resistance which was observed soon after antibiotic introduction has been studied extensively. Diverse mechanisms have been demonstrated and the genetic basis elucidated. The resilience of the prokaryote ecosystems to antibiotic stress has been realized. The paper presents these subjects briefly to afford an overview. The epidemiology of antibiotic resistance is dealt with and community practices in different countries are described. The role of high antibiotic usage environments is indicated. The implication of the wide use of antibiotics in animals has been pointed out. Steadily increasing antibiotic resistance and decreasing numbers of newer antibiotics appear to point to a post-antibiotic period during which treatment of infections would become increasingly difficult. This article attempts to review the global antimicrobial resistance scene and juxtaposes it to the Indian experience. The prevalence in India of antibiotic resistance among major groups of pathogens is described. The factors that determine the prevalent high antibiotic resistance rates have been highlighted. The future research activity to ensure continued utility of antibiotics in the control of infections has been indicated.

  6. Emerging antibiotic resistance in bacteria with special reference to India

    Indian Academy of Sciences (India)

    D Raghunath

    2008-11-01

    The antibiotic era started in the 1940s and changed the profile of infectious diseases and human demography. The burgeoning classes and numbers promised much and elimination of this major cause of human (and animal) morbidity appeared possible. Bacterial antibiotic resistance which was observed soon after antibiotic introduction has been studied extensively. Diverse mechanisms have been demonstrated and the genetic basis elucidated. The resilience of the prokaryote ecosystems to antibiotic stress has been realized. The paper presents these subjects briefly to afford an overview. The epidemiology of antibiotic resistance is dealt with and community practices in different countries are described. The role of high antibiotic usage environments is indicated. The implication of the wide use of antibiotics in animals has been pointed out. Steadily increasing antibiotic resistance and decreasing numbers of newer antibiotics appear to point to a post-antibiotic period during which treatment of infections would become increasingly difficult. This article attempts to review the global antimicrobial resistance scene and juxtaposes it to the Indian experience. The prevalence in India of antibiotic resistance among major groups of pathogens is described. The factors that determine the prevalent high antibiotic resistance rates have been highlighted. The future research activity to ensure continued utility of antibiotics in the control of infections has been indicated.

  7. The role of biofilms as environmental reservoirs of antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Jose Luis eBalcazar

    2015-10-01

    Full Text Available Antibiotic resistance has become a significant and growing threat to public and environmental health. To face this problem both at local and global scales, a better understanding of the sources and mechanisms that contribute to the emergence and spread of antibiotic resistance is required. Recent studies demonstrate that aquatic ecosystems are reservoirs of resistant bacteria and antibiotic resistance genes as well as potential conduits for their transmission to human pathogens. Despite the wealth of information about antibiotic pollution and its effect on the aquatic microbial resistome, the contribution of environmental biofilms to the acquisition and spread of antibiotic resistance has not been fully explored in aquatic systems. Biofilms are structured multicellular communities embedded in a self-produced extracellular matrix that acts as a barrier to antibiotic diffusion. High population densities and proximity of cells in biofilms also increases the chances for genetic exchange among bacterial species converting biofilms in hot spots of antibiotic resistance. This review focuses on the potential effect of antibiotic pollution on biofilm microbial communities, with special emphasis on ecological and evolutionary processes underlying acquired resistance to these compounds.

  8. The role of biofilms as environmental reservoirs of antibiotic resistance.

    Science.gov (United States)

    Balcázar, José L; Subirats, Jéssica; Borrego, Carles M

    2015-01-01

    Antibiotic resistance has become a significant and growing threat to public and environmental health. To face this problem both at local and global scales, a better understanding of the sources and mechanisms that contribute to the emergence and spread of antibiotic resistance is required. Recent studies demonstrate that aquatic ecosystems are reservoirs of resistant bacteria and antibiotic resistance genes as well as potential conduits for their transmission to human pathogens. Despite the wealth of information about antibiotic pollution and its effect on the aquatic microbial resistome, the contribution of environmental biofilms to the acquisition and spread of antibiotic resistance has not been fully explored in aquatic systems. Biofilms are structured multicellular communities embedded in a self-produced extracellular matrix that acts as a barrier to antibiotic diffusion. High population densities and proximity of cells in biofilms also increases the chances for genetic exchange among bacterial species converting biofilms in hot spots of antibiotic resistance. This review focuses on the potential effect of antibiotic pollution on biofilm microbial communities, with special emphasis on ecological and evolutionary processes underlying acquired resistance to these compounds.

  9. Genetic Regulation of Virulence and Antibiotic Resistance in Acinetobacter baumannii.

    Science.gov (United States)

    Kröger, Carsten; Kary, Stefani C; Schauer, Kristina; Cameron, Andrew D S

    2016-12-28

    Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance. Here, we review current knowledge regarding the regulation of virulence genes and antibiotic resistance in Acinetobacter baumannii. A survey of the two-component systems AdeRS, BaeSR, GacSA and PmrAB explains how each contributes to antibiotic resistance and virulence gene expression, while BfmRS regulates cell envelope structures important for pathogen persistence. A. baumannii uses the transcription factors Fur and Zur to sense iron or zinc depletion and upregulate genes for metal scavenging as a critical survival tool in an animal host. Quorum sensing, nucleoid-associated proteins, and non-classical transcription factors such as AtfA and small regulatory RNAs are discussed in the context of virulence and antibiotic resistance.

  10. Genetic Regulation of Virulence and Antibiotic Resistance in Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Carsten Kröger

    2016-12-01

    Full Text Available Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance. Here, we review current knowledge regarding the regulation of virulence genes and antibiotic resistance in Acinetobacter baumannii. A survey of the two-component systems AdeRS, BaeSR, GacSA and PmrAB explains how each contributes to antibiotic resistance and virulence gene expression, while BfmRS regulates cell envelope structures important for pathogen persistence. A. baumannii uses the transcription factors Fur and Zur to sense iron or zinc depletion and upregulate genes for metal scavenging as a critical survival tool in an animal host. Quorum sensing, nucleoid-associated proteins, and non-classical transcription factors such as AtfA and small regulatory RNAs are discussed in the context of virulence and antibiotic resistance.

  11. Genetic Regulation of Virulence and Antibiotic Resistance in Acinetobacter baumannii

    Science.gov (United States)

    Kröger, Carsten; Kary, Stefani C.; Schauer, Kristina; Cameron, Andrew D. S.

    2016-01-01

    Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance. Here, we review current knowledge regarding the regulation of virulence genes and antibiotic resistance in Acinetobacter baumannii. A survey of the two-component systems AdeRS, BaeSR, GacSA and PmrAB explains how each contributes to antibiotic resistance and virulence gene expression, while BfmRS regulates cell envelope structures important for pathogen persistence. A. baumannii uses the transcription factors Fur and Zur to sense iron or zinc depletion and upregulate genes for metal scavenging as a critical survival tool in an animal host. Quorum sensing, nucleoid-associated proteins, and non-classical transcription factors such as AtfA and small regulatory RNAs are discussed in the context of virulence and antibiotic resistance. PMID:28036056

  12. Antibiotic resistance of bacterial isolates from aquatic animals and its prevention and control%水产动物源细菌耐药性与预防控制

    Institute of Scientific and Technical Information of China (English)

    李国烈; 李林桂; 房文红

    2012-01-01

    Bacterial resistance is the ability of a disease-causing bacterium to resist being killed by antibiotics. The formation of bacterial resistance is the result of the development of bacterial evolution and the manifest of bacterial adaptability; however, it threatens the development of aquaculture and human health. Firstly, this paper summarized the research progress on the bacterial resistance in aquatic animals in recent years, including plasmid-mediated resistance of bacteria, resistance gene of bacterial isolates from aquatic animals, and the genetic mechanism of antibiotic resistance and so on. Secondly, the paper analyzed the harm of bacterial resistance, which included the pathogen of bacterial resistance that caused epidemics and the antibiotic resistance of bacterial isolates from aquatic animals that threatened public health. Finally, from rational and standardized use of drugs, speeding up the development and application of aquatic vaccines and new antimicrobial drugs alternatives, strengthening of the surveillance about pathogen isolates from aquatic animals and so on, the paper provided some valuable methods and strategies on the prevention and control for bacterial resistance in aquatic animals.%细菌耐药性是指细菌对于抗菌药物作用的耐受性。细菌耐药性的形成,是细菌进化发展的结果,是细菌适应性的表现,但它却给养殖业的发展和人类的健康带来威胁。本文首先综述了水产动物源细菌耐药性研究现状,主要包括质粒介导的水产动物源细菌耐药性、细菌耐药基因、细菌耐药性遗传学机制等;其次,从病原菌耐药性会导致水产疾病流行爆发和水产细菌耐药性对人类公共卫生安全的影响两方面,分析了水产动物源细菌耐药性的危害;最后,从合理、规范用药,加快水产疫苗和新型抗菌药物替代品的研制与应用,加强水产动物致病菌耐药性监测等方面,提出了预防和控制

  13. Host-dependent Induction of Transient Antibiotic Resistance: A Prelude to Treatment Failure.

    Science.gov (United States)

    Kubicek-Sutherland, Jessica Z; Heithoff, Douglas M; Ersoy, Selvi C; Shimp, William R; House, John K; Marth, Jamey D; Smith, Jeffrey W; Mahan, Michael J

    2015-09-01

    Current antibiotic testing does not include the potential influence of host cell environment on microbial susceptibility and antibiotic resistance, hindering appropriate therapeutic intervention. We devised a strategy to identify the presence of host-pathogen interactions that alter antibiotic efficacy in vivo. Our findings revealed a bacterial mechanism that promotes antibiotic resistance in vivo at concentrations of drug that far exceed dosages determined by standardized antimicrobial testing. This mechanism has escaped prior detection because it is reversible and operates within a subset of host tissues and cells. Bacterial pathogens are thereby protected while their survival promotes the emergence of permanent drug resistance. This host-dependent mechanism of transient antibiotic resistance is applicable to multiple pathogens and has implications for the development of more effective antimicrobial therapies.

  14. Emergence and dissemination of antibiotic resistance: A global problem

    OpenAIRE

    Choudhury, R; Panda, S.; D.V. Singh

    2012-01-01

    Antibiotic resistance is a major problem in clinical health settings. Interestingly the origin of many of antibiotic resistance mechanisms can be traced back to non-pathogenic environmental organisms. Important factors leading to the emergence and spread of antibiotic resistance include absence of regulation in the use of antibiotics, improper waste disposal and associated transmission of antibiotic resistance genes in the community through commensals. In this review, we discussed the impact ...

  15. Frequency of Bacterial Contamination and Antibiotic Resistance Patterns in Devices and in Personnel of Endoscopy and Colonoscopy Units

    Directory of Open Access Journals (Sweden)

    Torabi, P. (BSc

    2014-06-01

    Full Text Available Background and Objective: This study was aimed to determine the extent of bacterial contamination and drug resistance patterns of isolates colonized in colonoscope and endoscope and in relevant personnel. Material and Methods: A total of 107 samples were obtained from staff of endoscopy and colonoscopy units (SEU and SCU and gastroenterological imaging equipment. For isolation and identification of the bacteria, swab culture method and biochemical identification test were used, respectively. Antimicrobial resistance profiles, multi-drug resistance (MDR patterns and phenetic relatedness of these isolates were also analyzed according to standard methods. Results: Most frequent pathogenic bacteria among the SEU and gastroenterological imaging related equipments were included S. aureus (20.8 % and 0 %; Enterococcus spp. (0 % and 5.4%; Pseudomonas spp. (0% and 13.5 %, and Clostridium difficile (0% and 12.5%. Analysis of resistance phenotypes showed a high frequency of MDR phenotypes among the SEU (82.1%, and also in endoscopes, colonoscopes, and other equipments (20%, 50% and 100%, respectively. Phylotyping of S. epidermidis isolates showed the role of staff in transmission of resistance strains to medical equipments and also circulation of strains with identical resistance phenotype among the studied samples. Conclusion: High frequency of pathogenic bacteria in colonoscopes, endoscopes and in the staff of endoscopy & colonoscopy units, and also contamination of these instruments with MDR pathogens emphasize the need for proper disinfection of endoscopes and colonoscopes and also instruction of staff in these units. Key words: Bacterial Contamination; Endoscope; Colonoscope; Antimicrobial Resistance; Gastrointestinal Disease.

  16. The multifaceted roles of antibiotics and antibiotic resistance in nature

    Directory of Open Access Journals (Sweden)

    Saswati eSengupta

    2013-03-01

    Full Text Available Antibiotics are chemotherapeutic agents, which have been a very powerful tool in the clinical management of bacterial diseases since the 1940s. However, benefits offered by these magic bullets have been substantially lost in subsequent days following the widespread emergence and dissemination of antibiotic resistant strains. While it is obvious that excessive and imprudent use of antibiotics significantly contributes to the emergence of resistant strains, antibiotic-resistance is also observed in natural bacteria of remote places unlikely to be impacted by human intervention. Both antibiotic biosynthetic genes and resistance-conferring genes have been known to evolve billions of years ago, long before clinical use of antibiotics. Hence it appears that antibiotics and antibiotics resistance determinants have some other roles in nature, which often elude our attention because of overemphasis on the therapeutic importance of antibiotics and the crisis imposed by the antibiotic-resistance in pathogens. In the natural milieu, antibiotics are often found to be present in subinhibitory concentrations acting as signalling molecules supporting quorum sensing and biofilm formation. They also play an important role in the production of virulence factors and influence host-parasite interactions (e.g., phagocytosis, adherence to the target cell and so on. The evolutionary and ecological aspects of antibiotics and antibiotic-resistance in the naturally occurring microbial community are little understood. Therefore, the actual role of antibiotics in nature warrants in-depth investigations. Studies on such an intriguing behaviour of the microorganisms promise insight into the intricacies of the microbial physiology and are likely to provide some lead in controlling the emergence and subsequent dissemination of antibiotic resistance. This article highlights some of the recent findings on the role of antibiotics and genes that confer resistance to antibiotics in

  17. Bacterial Density, Serotype Distribution and Antibiotic Resistance of Pneumococcal Strains from the Nasopharynx of Peruvian Children Before and After Pneumococcal Conjugate Vaccine 7

    Science.gov (United States)

    Hanke, Christiane R.; Grijalva, Carlos G.; Chochua, Sopio; Pletz, Mathias W.; Hornberg, Claudia; Edwards, Kathryn M.; Griffin, Marie R.; Verastegui, Hector; Gil, Ana I.; Lanata, Claudio F.; Klugman, Keith P.; Vidal, Jorge E.

    2016-01-01

    Background Pneumococcal conjugate vaccines (PCV) have decreased nasopharyngeal carriage of vaccine-types but little data exists from rural areas. We investigated bacterial density, serotype distribution and antibiotic resistance of pneumococcal strains within the nasopharynx of young children in the Peruvian Andes, two years after PCV7 was introduced. Methods Pneumococcal strains were isolated from a subset of 125 children from our Peruvian cohort, who entered the study in 2009 and had pneumococcus detected in the nasopharynx in both 2009 and during follow-up in 2011. Strains were quellung-serotyped and tested for susceptibility to antibiotics. Bacterial density was determined by qPCR. Results The prevalence of PCV7 strains decreased from 48% in 2009 to 28.8% in 2011, whereas non-PCV7 types increased from 52% to 71.2% (p=0.002). There was a 3.5-fold increase in carriage of serotype 6C in 2011 (p=0.026). Vaccination with PCV7 did not affect pneumococcal density in children colonized by a PCV7 type but did increased density in those colonized with a non-PCV7 type. Antibiotic resistance did not change after vaccine introduction; strains were non-susceptible to tetracycline (97.2%), trimethoprim-sulfamethoxazole (56.4%), penicillin (34%), erythromycin (22.4%), chloramphenicol (18.8%) and clindamycin (12.4%). Conclusions Serotype replacement was observed post-PCV7 vaccination with a concomitant, not previously recognized, increased nasopharyngeal density. PMID:26974749

  18. 新生儿血培养常见病原菌与抗生素耐药%Bacterial spectrum of neonatal blood cultures and antibiotic resistance

    Institute of Scientific and Technical Information of China (English)

    崔曙东; 邵小松; 胡毓华; 章晔; 陈筱青; 管亚飞

    2011-01-01

    目的 了解新生儿血培养细菌种类及抗生素耐药情况.方法 收集662份新生儿血培养标本,对其中培养结果阳性的45份标本进行细菌分类和抗生素耐药分析.结果 甲氧西林敏感凝固酶阴性葡萄球菌(MSCNS)占首位,其次是耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)、金黄色葡萄球菌、革兰氏阴性杆菌.在非头孢菌素类的抗生素中,对青霉素耐药的比例最高(87.18%),其次是红霉素;对头孢菌素及头霉素类耐药皆在50%以上,其中头孢呋肟耐药比例达100%.结论 新生儿条件致病菌感染比例增加,抗生素使用导致非自然选择耐药菌感染增多.%Objective To study the bacterial spectrum of neonatal blood cultures and antibiotic resistance Methods Six hundred and sixty-two blood cultures from newborn infants were collected.Forty-five positive bacterial blood cultures were performed by classification of bacteria and antibiotic resistance analysis. Results Methicillin-sensitive coagulase-negative staphylococci samples occupied the first place, which was followed in an order of methicillin-resistant coagulase-negative staphylococci >staphylococcus aureus>Gram-negative bacillus samples. Among antibiotic resistant bacteria (expect cephalosporin and cephamycins), penicillin-resistant bacteria occupied the first place(87. 18%), which was followed by erythromycir-resistant bacteria. Cephalosporin and cephamycins resistant bacteria were at least 50%, in which cefuroxime-resistant bacteria were 100%. Conclusion The incidence of coagulase-negative staphylococci sepsis in newborn infants increases. Non-natural selection based antibiotic-resistant bacteria infection is increased because of the extensive use of antibiotics.

  19. Inhibition of bacterial growth by iron oxide nanoparticles with and without attached drug: Have we conquered the antibiotic resistance problem?

    Science.gov (United States)

    Armijo, Leisha M.; Jain, Priyanka; Malagodi, Angelina; Fornelli, F. Zuly; Hayat, Allison; Rivera, Antonio C.; French, Michael; Smyth, Hugh D. C.; Osiński, Marek

    2015-03-01

    Pseudomonas aeruginosa is among the top three leading causative opportunistic human pathogens, possessing one of the largest bacterial genomes and an exceptionally large proportion of regulatory genes therein. It has been known for more than a decade that the size and complexity of the P. aeruginosa genome is responsible for the adaptability and resilience of the bacteria to include its ability to resist many disinfectants and antibiotics. We have investigated the susceptibility of P. aeruginosa bacterial biofilms to iron oxide (magnetite) nanoparticles (NPs) with and without attached drug (tobramycin). We also characterized the susceptibility of zero-valent iron NPs, which are known to inactivate microbes. The particles, having an average diameter of 16 nm were capped with natural alginate, thus doubling the hydrodynamic size. Nanoparticle-drug conjugates were produced via cross-linking drug and alginate functional groups. Drug conjugates were investigated in the interest of determining dosage, during these dosage-curve experiments, NPs unbound to drug were tested in cultures as a negative control. Surprisingly, we found that the iron oxide NPs inhibited bacterial growth, and thus, biofilm formation without the addition of antibiotic drug. The inhibitory dosages of iron oxide NPs were investigated and the minimum inhibitory concentrations are presented. These findings suggest that NP-drug conjugates may overcome the antibiotic drug resistance common in P. aeruginosa infections.

  20. A conformational switch in the active site of BT_2972, a methyltransferase from an antibiotic resistant pathogen B. thetaiotaomicron.

    Directory of Open Access Journals (Sweden)

    Veerendra Kumar

    Full Text Available Methylation is one of the most common biochemical reactions involved in cellular and metabolic functions and is catalysed by the action of methyltransferases. Bacteroides thetaiotaomicron is an antibiotic-resistant bacterium that confers resistance through methylation, and as yet, there is no report on the structure of methyltransferases from this bacterium. Here, we report the crystal structure of an AdoMet-dependent methyltransferase, BT_2972 and its complex with AdoMet and AdoHcy for B. thetaiotaomicron VPI-5482 strain along with isothermal titration calorimetric assessment of the binding affinities. Comparison of the apo and complexed BT_2972 structures reveals a significant conformational change between open and closed forms of the active site that presumably regulates the association with cofactors and may aid interaction with substrate. Together, our analysis suggests that BT_2972 is a small molecule methyltransferase and might catalyze two O-methylation reaction steps involved in the ubiquinone biosynthesis pathway.

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

    Science.gov (United States)

    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

  2. Emergence and dissemination of antibiotic resistance: a global problem.

    Science.gov (United States)

    Choudhury, R; Panda, S; Singh, D V

    2012-01-01

    Antibiotic resistance is a major problem in clinical health settings. Interestingly the origin of many of antibiotic resistance mechanisms can be traced back to non-pathogenic environmental organisms. Important factors leading to the emergence and spread of antibiotic resistance include absence of regulation in the use of antibiotics, improper waste disposal and associated transmission of antibiotic resistance genes in the community through commensals. In this review, we discussed the impact of globalisation on the transmission of antibiotic resistance genes in bacteria through immigration and export/import of foodstuff. The significance of surveillance to define appropriate use of antibiotics in the clinic has been included as an important preventive measure.

  3. Elucidating the potential for transfer of antibiotic resistance genes trhough agro-ecosystems

    Science.gov (United States)

    Increases in the occurrence of antibiotic resistance (AR) in clinical pathogens raises concerns about how resistance is spread within and between human, environmental and agricultural eco-systems. Livestock manure applied to soil may increase AR bacterial concentrations as a result of addition of ma...

  4. Biofilm formation and antibiotic resistance in Salmonella Typhimurium are affected by different ribonucleases.

    Science.gov (United States)

    Saramago, Margarida; Domingues, Susana; Viegas, Sandra Cristina; Arraiano, Cecília Maria

    2014-01-01

    Biofilm formation and antibiotic resistance are important determinants for bacterial pathogenicity. Ribonucleases control RNA degradation and there is increasing evidence that they have an important role in virulence mechanisms. In this report, we show that ribonucleases affect susceptibility against ribosome-targeting antibiotics and biofilm formation in Salmonella.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-05-07

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

  7. Identification of a small molecule that simultaneously suppresses virulence and antibiotic resistance of Pseudomonas aeruginosa.

    Science.gov (United States)

    Guo, Qiaoyun; Wei, Yu; Xia, Bin; Jin, Yongxin; Liu, Chang; Pan, Xiaolei; Shi, Jing; Zhu, Feng; Li, Jinlong; Qian, Lei; Liu, Xinqi; Cheng, Zhihui; Jin, Shouguang; Lin, Jianping; Wu, Weihui

    2016-01-11

    The rising antibiotic resistance of bacteria imposes a severe threat on human health. Inhibition of bacterial virulence is an alternative approach to develop new antimicrobials. Molecules targeting antibiotic resistant enzymes have been used in combination with cognate antibiotics. It might be ideal that a molecule can simultaneously suppress virulence factors and antibiotic resistance. Here we combined genetic and computer-aided inhibitor screening to search for such molecules against the bacterial pathogen Pseudomonas aeruginosa. To identify target proteins that control both virulence and antibiotic resistance, we screened for mutants with defective cytotoxicity and biofilm formation from 93 transposon insertion mutants previously reported with increased antibiotic susceptibility. A pyrD mutant displayed defects in cytotoxicity, biofilm formation, quorum sensing and virulence in an acute mouse pneumonia model. Next, we employed a computer-aided screening to identify potential inhibitors of the PyrD protein, a dihydroorotate dehydrogenase (DHODase) involved in pyrimidine biosynthesis. One of the predicted inhibitors was able to suppress the enzymatic activity of PyrD as well as bacterial cytotoxicity, biofilm formation and antibiotic resistance. A single administration of the compound reduced the bacterial colonization in the acute mouse pneumonia model. Therefore, we have developed a strategy to identify novel treatment targets and antimicrobial molecules.

  8. Emergence and spread of antibiotic resistance: setting a parameter space

    OpenAIRE

    Martínez, José Luis; Baquero, Fernando

    2014-01-01

    The emergence and spread of antibiotic resistance among human pathogens is a relevant problem for human health and one of the few evolution processes amenable to experimental studies. In the present review, we discuss some basic aspects of antibiotic resistance, including mechanisms of resistance, origin of resistance genes, and bottlenecks that modulate the acquisition and spread of antibiotic resistance among human pathogens. In addition, we analyse several parameters that modulate the evol...

  9. Insights into antibiotic resistance through metagenomic approaches.

    Science.gov (United States)

    Schmieder, Robert; Edwards, Robert

    2012-01-01

    The consequences of bacterial infections have been curtailed by the introduction of a wide range of antibiotics. However, infections continue to be a leading cause of mortality, in part due to the evolution and acquisition of antibiotic-resistance genes. Antibiotic misuse and overprescription have created a driving force influencing the selection of resistance. Despite the problem of antibiotic resistance in infectious bacteria, little is known about the diversity, distribution and origins of resistance genes, especially for the unculturable majority of environmental bacteria. Functional and sequence-based metagenomics have been used for the discovery of novel resistance determinants and the improved understanding of antibiotic-resistance mechanisms in clinical and natural environments. This review discusses recent findings and future challenges in the study of antibiotic resistance through metagenomic approaches.

  10. Insects represent a link between food animal farms and the urban environment for antibiotic resistance traits.

    Science.gov (United States)

    Zurek, Ludek; Ghosh, Anuradha

    2014-06-01

    Antibiotic-resistant bacterial infections result in higher patient mortality rates, prolonged hospitalizations, and increased health care costs. Extensive use of antibiotics as growth promoters in the animal industry represents great pressure for evolution and selection of antibiotic-resistant bacteria on farms. Despite growing evidence showing that antibiotic use and bacterial resistance in food animals correlate with resistance in human pathogens, the proof for direct transmission of antibiotic resistance is difficult to provide. In this review, we make a case that insects commonly associated with food animals likely represent a direct and important link between animal farms and urban communities for antibiotic resistance traits. Houseflies and cockroaches have been shown to carry multidrug-resistant clonal lineages of bacteria identical to those found in animal manure. Furthermore, several studies have demonstrated proliferation of bacteria and horizontal transfer of resistance genes in the insect digestive tract as well as transmission of resistant bacteria by insects to new substrates. We propose that insect management should be an integral part of pre- and postharvest food safety strategies to minimize spread of zoonotic pathogens and antibiotic resistance traits from animal farms. Furthermore, the insect link between the agricultural and urban environment presents an additional argument for adopting prudent use of antibiotics in the food animal industry.

  11. Dissemination of Enterococcus faecalis and Enterococcus faecium in a ricotta processing plant and evaluation of pathogenic and antibiotic resistance profiles.

    Science.gov (United States)

    Fernandes, Meg da Silva; Fujimoto, Graciela; de Souza, Leandro Pio; Kabuki, Dirce Yorika; da Silva, Márcio José; Kuaye, Arnaldo Yoshiteru

    2015-04-01

    In this work, the sources of contamination by Enterococcus spp. in a ricotta processing line were evaluated. The isolated strains were tested for virulence genes (gelE, cylA,B, M, esp, agg, ace, efaA, vanB), expression of virulence factors (hemolysin and gelatinase), and the resistance to 10 different antibiotics. Enterococcus faecium and Enterococcus faecalis were subjected to discriminatory identification by intergenic spacer region (ITS)-polymerase chain reaction and sequencing of the ITS region. The results showed that Enterococcus spp. was detected in the raw materials, environment samples and the final product. None of the 107 Enterococcus isolates were completely free from all virulence genes considered. A fraction of 21.5% of the isolates containing all of the genes of the cylA, B, M operon also expressed β-hemolysis. Most of the isolates showed the gelE gene, but only 9.3% were able to hydrolyze gelatin. In addition, 23.5% of the observed Enterococcus isolates had the vanB gene but were susceptible to vancomycin in vitro. The dissemination of antibiotic-resistant enterococci was revealed in this study: 19.3% of the E. faecium samples and 78.0% of the E. faecalis samples were resistant to at least one of the antibiotics tested. Sequencing of region discriminated 5 and 7 distinct groups among E. faecalis and E. faecium, respectively. Although some similarity was observed among some of the isolates, all E. faecalis and E. faecium isolates had genetic differences both in the ITS region and in the virulence profile, which makes them different from each other.

  12. Antibiotic resistance in probiotic bacteria

    Directory of Open Access Journals (Sweden)

    Miguel eGueimonde

    2013-07-01

    Full Text Available Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The main probiotic bacteria are strains belonging to the genera Lactobacillus and Bifidobacterium, although other representatives, such as Bacillus or Escherichia coli strains, have also been used. Lactobacillus and Bifidobacterium are two common inhabitants of the human intestinal microbiota. Also, some species are used in food fermentation processes as starters, or as adjunct cultures in the food industry. With some exceptions, antibiotic resistance in these beneficial microbes does not constitute a safety concern in itself, when mutations or intrinsic resistance mechanisms are responsible for the resistance phenotype. In fact, some probiotic strains with intrinsic antibiotic resistance could be useful for restoring the gut microbiota after antibiotic treatment. However, specific antibiotic resistance determinants carried on mobile genetic elements, such as tetracycline resistance genes, are often detected in the typical probiotic genera, and constitute a reservoir of resistance for potential food or gut pathogens, thus representing a serious safety issue.

  13. Antibiotic resistance of Vibrio parahaemolyticus and Vibrio vulnificus in various countries: A review.

    Science.gov (United States)

    Elmahdi, Sara; DaSilva, Ligia V; Parveen, Salina

    2016-08-01

    Vibrio parahaemolyticus and Vibrio vulnificus are the leading causes of seafood associated infections and mortality in the United States. The main syndromes caused by these pathogens are gastroenteritis, wound infections, and septicemia. This article reviewed the antibiotic resistance profile of V. parahaemolyticus and V. vulnificus in the United States and other countries including Italy, Brazil, Philippines, Malaysia, Thailand, China, India, Iran, South Africa and Australia. The awareness of antimicrobial resistance of these two pathogens is not as well documented as other foodborne bacterial pathogens. Vibrio spp. are usually susceptible to most antimicrobials of veterinary and human significance. However, many studies reported that V. vulnificus and V. parahaemolyticus showed multiple-antibiotic resistance due to misuse of antibiotics to control infections in aquaculture production. In addition, both environmental and clinical isolates showed similar antibiotic resistance profiles. Most frequently observed antibiotic resistance profiles involved ampicillin, penicillin and tetracycline regardless of the countries. The presence of multiple-antibiotic resistant bacteria in seafood and aquatic environments is a major concern in fish and shellfish farming and human health.

  14. A historical overview of bacteriophage therapy as an alternative to antibiotics for the treatment of bacterial pathogens.

    Science.gov (United States)

    Wittebole, Xavier; De Roock, Sophie; Opal, Steven M

    2014-01-01

    The seemingly inexorable spread of antibiotic resistance genes among microbial pathogens now threatens the long-term viability of our current antimicrobial therapy to treat severe bacterial infections such as sepsis. Antibiotic resistance is reaching a crisis situation in some bacterial pathogens where few therapeutic alternatives remain and pan-resistant strains are becoming more prevalent. Non-antibiotic therapies to treat bacterial infections are now under serious consideration and one possible option is the therapeutic use of specific phage particles that target bacterial pathogens. Bacteriophage therapy has essentially been re-discovered by modern medicine after widespread use of phage therapy in the pre-antibiotic era lost favor, at least in Western countries, after the introduction of antibiotics. We review the current therapeutic rationale and clinical experience with phage therapy as a treatment for invasive bacterial infection as novel alternative to antimicrobial chemotherapy.

  15. Distribution of 1 037 strains of pathogenic bacteria and antibiotic resistance of the main pathogenic bacteria analysis%1037株病原菌分布及其主要病原菌耐药情况分析

    Institute of Scientific and Technical Information of China (English)

    潘开拓; 姜朝新; 王陈龙; 黄燕新; 曾令恒; 曾庆洋

    2013-01-01

      目的分析佛山市南海区第三人民医院检出的病原菌分布及其主要病原菌耐药情况,为临床合理用药和控制医院感染提供依据.方法采用法国生物梅里埃公司ATB微生物鉴定仪对2010年1月至2011年12月从该院患者的各类标本中分离的1037株病原菌进行鉴定,药敏试验采用琼脂纸片扩散法及法国生物梅里埃ATB药敏板条.结果检出病原菌以革兰阴性杆菌为主占58.4%、革兰阳性球菌次之占27.3%,真菌占13.2%,除真菌外的其他主要病原菌的抗菌药物耐药率普遍较高.结论医院容易发生医院感染,应加强其病原菌分布及其抗菌药物耐药情况监测,以指导临床合理用药,降低医院感染率.%Objective To analyze the distribution of pathogenic bacteria isolated from our hospital and the an-tibiotic resistance of the main pathogenic bacteria ,to provide a basis for clinical rational drug use and control the hos-pital infection .Methods 1 037 strains of pathogenic bacteria separated from patients in our hospital during Jan 2010-Dec 2011 were identified by ATB biomerieux from France and detected the antibiotic resistance by Kirby-Bauer(K-B) agar tape diffusion and drug sensitivity test tape of ATB biomerieux from France .Results The Gram-negative bacte-ria(58 .4% ) were the main pathogenic bacteria ,as followed by Gram-positive bacteria(27 .3% ) ,and fungi(13 .2% ) . The antibiotic resistance rates of the main pathogenic bacteria except fungi were high .Conclusion Patients easily suffered hospital infection ,it should strengthen the monitoring of the distribution of pathogenic bacteria and their an-tibiotic resistance so as to help the doctors to choose the antibiotics reasonably and reduce the rate of hospital infec-tion .

  16. Horizontal gene transfer in the human gastrointestinal tract: potential spread of antibiotic resistance genes

    Directory of Open Access Journals (Sweden)

    Huddleston JR

    2014-06-01

    Full Text Available Jennifer R HuddlestonBiology Department, Abilene Christian University, Abilene, TX, USAAbstract: Bacterial infections are becoming increasingly difficult to treat due to widespread antibiotic resistance among pathogens. This review aims to give an overview of the major horizontal transfer mechanisms and their evolution and then demonstrate the human lower gastrointestinal tract as an environment in which horizontal gene transfer of resistance determinants occurs. Finally, implications for antibiotic usage and the development of resistant infections and persistence of antibiotic resistance genes in populations as a result of horizontal gene transfer in the large intestine will be discussed.Keywords: gut microbiome, conjugation, natural transformation, transduction

  17. Elemente de structură bacteriană și mecanismele transmiterii rezistenței la antibiotice / Elements of bacterial structure and mechanisms of antibiotic resistance transmission

    Directory of Open Access Journals (Sweden)

    Alexandru O. Doma

    2015-12-01

    Full Text Available The aim of this bibliographic essay is to refresh the knowledge of veterinarians in the field of therapy and bacterial resistance. Are summarized, in a didactic manner: the bacteria classification, the overall structure of the cell wall, the general characterization of antibiotics, the fundamental modes of action of antibiotics, the main interactions and side phenomena antibiotics and toxic products. Installing and effects of bacterial resistance to antibiotics is presented in detail, being given the basic concepts about resistance mechanisms as: the drug inactivation or misappropriation of the pathway, enzyme target altering or structure, low accumulation of antibiotic resistance in bacterial cells. They are also presented: the natural antibiotic resistance (epigenetic, the gained antibiotic resistance, the genetic adaptation (by mutation and selection and the genetic acquisition. By means of resistance means all the mechanisms by which bacteria can reduce or total inactivate the antimicrobial activity. In this regard are presented: phases of the resistance installation and antibiotics’ modification / inactivation, not being omitted also the trends in the evolution of resistance to antibiotics and environmental impacts analysis, the results of the imprudent using of the anti-infectives (like veterinary antibiotics in soil and water, the antibiotic resistance in the genetic modified crops or the long-term effects on ecosystems and them consequences.

  18. Hospital effluents are one of several sources of metal, antibiotic resistance genes and bacterial markers disseminated in Sub-Saharan urban rivers

    Directory of Open Access Journals (Sweden)

    Amandine Laffite

    2016-07-01

    Full Text Available Data concerning the occurrence of emerging biological contaminants such as antibiotic resistance genes (ARGs and fecal indicator bacteria (FIB in aquatic environments in Sub-Saharan African countries is limited. On the other hand, antibiotic resistance remains a worldwide problem which may pose serious potential risks to human and animal health. Consequently, there is a growing number of reports concerning the prevalence and dissemination of these contaminants into various environmental compartments. Sediments provide the opportunity to reconstruct the pollution history and evaluate impacts so this study investigates the abundance and distribution of toxic metals, FIB, and ARGs released from hospital effluent wastewaters and their presence in river sediments receiving systems. ARGs (blaTEM, blaCTX-M, blaSHV, and aadA, total bacterial load, and selected bacterial species FIB (E. coli, Enterococcus (ENT and Pseudomonas species (Psd were quantified by targeting species specific genes using quantitative PCR (qPCR in total DNA extracted from the sediments recovered from 4 hospital outlet pipes (HOP and their river receiving systems in the City of Kinshasa in the Democratic Republic of the Congo. The results highlight the great concentration of toxic metals in HOP, reaching the values (in mg kg-1 of 47.9 (Cr, 213.6 (Cu, 1434.4 (Zn, 2.6 (Cd, 281.5 (Pb, and 13.6 (Hg. The results also highlight the highest (P˂0.05 values of 16S rRNA, FIB, and ARGs copy numbers in all sampling sites including upstream (control site, discharge point, and downstream of receiving rivers, indicating that the hospital effluent water is not an exclusive source of the biological contaminants entering the urban rivers. Significant correlation were observed between (i all analyzed ARGs and total bacterial load (16S rRNA 0.51 to 0.72 (p<0.001, n=65; (ii ARGs (except blaTEM and FIB and Psd 0.57 < r < 0.82 (p<0.001, n=65; and (iii ARGs (except blaTEM and toxic metals (Cd, Cr, Cu

  19. The role of biofilms as environmental reservoirs of antibiotic resistance

    OpenAIRE

    Balcázar, José L.; Subirats, Jéssica; Borrego, Carles M.

    2015-01-01

    Antibiotic resistance has become a significant and growing threat to public and environmental health. To face this problem both at local and global scales, a better understanding of the sources and mechanisms that contribute to the emergence and spread of antibiotic resistance is required. Recent studies demonstrate that aquatic ecosystems are reservoirs of resistant bacteria and antibiotic resistance genes as well as potential conduits for their transmission to human pathogens. Despite the w...

  20. Antibiotic-Resistant Bacteria.

    Science.gov (United States)

    Longenecker, Nevin E.; Oppenheimer, Dan

    1982-01-01

    A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)

  1. Influence of Chicken Manure Fertilization on Antibiotic-Resistant Bacteria in Soil and the Endophytic Bacteria of Pakchoi.

    Science.gov (United States)

    Yang, Qingxiang; Zhang, Hao; Guo, Yuhui; Tian, Tiantian

    2016-01-01

    Animal manure is commonly used as fertilizer for agricultural crops worldwide, even though it is believed to contribute to the spread of antibiotic resistance from animal intestines to the soil environment. However, it is unclear whether and how there is any impact of manure fertilization on populations and community structure of antibiotic-resistant endophytic bacteria (AREB) in plant tissues. To investigate the effect of manure and organic fertilizer on endophytic bacterial communities, pot experiments were performed with pakchoi grown with the following treatments: (1) non-treated; (2) chicken manure-treated and (3) organic fertilizer-treated. Manure or organic fertilizer significantly increased the abundances of total cultivable endophytic bacteria (TCEB) and AREB in pakchoi, and the effect of chicken manure was greater than that of organic fertilizer. Further, 16S rDNA sequencing and the phylogenetic analysis indicated that chicken manure or organic fertilizer application increased the populations of multiple antibiotic-resistant bacteria (MARB) in soil and multiple antibiotic-resistant endophytic bacteria (MAREB) in pakchoi. The identical multiple antibiotic-resistant bacterial populations detected in chicken manure, manure- or organic fertilizer-amended soil and the vegetable endophytic system were Brevundimonas diminuta, Brachybacterium sp. and Bordetella sp., suggesting that MARB from manure could enter and colonize the vegetable tissues through manure fertilization. The fact that some human pathogens with multiple antibiotic resistance were detected in harvested vegetables after growing in manure-amended soil demonstrated a potential threat to human health.

  2. Mission Critical: Preventing Antibiotic Resistance

    Science.gov (United States)

    ... Button Past Emails CDC Features Mission Critical: Preventing Antibiotic Resistance Recommend on Facebook Tweet Share Compartir Can you ... spp. So, what can we do to prevent antibiotic resistance in healthcare settings? Patients, healthcare providers, healthcare facility ...

  3. Antibiotic-Resistant Gonorrhea (ARG)

    Science.gov (United States)

    ... Twitter STD on Facebook Sexually Transmitted Diseases (STDs) Antibiotic-Resistant Gonorrhea Basic Information Recommend on Facebook Tweet ... Page Surveillance Trends and Treatment Challenges Laboratory Issues Antibiotic resistance (AR) is the ability of bacteria to ...

  4. Background antibiotic resistance patterns in antibiotic-free pastured poultry production

    Science.gov (United States)

    Antibiotic resistance (AR) is a significant public health issue, and agroecosystems are often viewed as major environmental sources of antibiotic resistant foodborne pathogens. While the use of antibiotics in agroecosystems can potentially increase AR, appropriate background resistance levels in th...

  5. 儿童社区获得性肺炎323例病原菌分布与耐药性研究%Detection of pathogenic bacteria and antibiotic resistance in 323 children with community acquired pneumonia

    Institute of Scientific and Technical Information of China (English)

    王军; 郭丽萍; 汤进; 马维维

    2011-01-01

    目的 了解2008-2010年于本院住院的儿童社区获得性肺炎(community acquired pneumonia,CAP)病原菌分布及耐药情况 方法 采用法国梅里埃ATB expression鉴定及药敏仪,对儿童CAP患儿进行痰细菌培养、鉴定及药物敏感试验 结果 被检出的323株细菌结果中,G+球菌占38 4%,其中主要为肺炎链球菌(streptococcus pneumoniae,SP)(27 9%),金黄色葡萄球菌(staphylococcus aureus,SA)(10 5%);G-杆菌占61 6%,最常见的是大肠埃希菌(escherichia coli,E coli) (24 5%),肺炎克雷伯杆菌(klebsiella pneumoniae,K pn)(13 9%),流感嗜血杆菌(haemophilus influenzae,HI)(8%) SP感染率>6月患儿与<6月患儿有非常显著差异,且在>6月患儿各年龄组居首位 E coli和K pn感染率随着年龄增长下降,<6月与>6月患儿之间有显著差异 产ESBLs株的K pn和E coli检出率高达71 1%和77 2%;HI对氨苄西林的耐药率为66 7%;而SP对红霉素的耐药率高达98 9% 结论 本地区下呼吸道感染的细菌病原学的分布及变化,耐药情况,对合理选择抗生素,减缓耐药菌产生具有重要意义.%[Objective] To provide reference for the treatment for clinicians during the recent two years investigation of bacterial and antibiotic resistance analysis of hospitalized children with community acquired pneumonia(CAP)in some are-as of Hanzhong. [Method] The sputum bacterial culture, identification and drug sensitive test were made for children with CAP by rench Merieux ATB expression identification and susceptibility meter. [Results] Of the 323 strains of bacterial pathogens, 11 kinds of bacterial pathogens were isolated. Gram-positive cocci accounted for 38. 4%. Of them were streptococcus pneumoniae (SP) (27. 9%) and staphylococcus aureus (SA) (10. 5%). Gram-negative bacilli accounted for 61.6%, the predominant isolate was Escherichia coll (E. Coli) (24. 5%), followed by klebsiella pneumoniae (K. Pn) (13. 9%) and haemophilus influenzae (HI) (8

  6. Mechanisms of antibiotic resistance in enterococci.

    Science.gov (United States)

    Miller, William R; Munita, Jose M; Arias, Cesar A

    2014-10-01

    Multidrug-resistant (MDR) enterococci are important nosocomial pathogens and a growing clinical challenge. These organisms have developed resistance to virtually all antimicrobials currently used in clinical practice using a diverse number of genetic strategies. Due to this ability to recruit antibiotic resistance determinants, MDR enterococci display a wide repertoire of antibiotic resistance mechanisms including modification of drug targets, inactivation of therapeutic agents, overexpression of efflux pumps and a sophisticated cell envelope adaptive response that promotes survival in the human host and the nosocomial environment. MDR enterococci are well adapted to survive in the gastrointestinal tract and can become the dominant flora under antibiotic pressure, predisposing the severely ill and immunocompromised patient to invasive infections. A thorough understanding of the mechanisms underlying antibiotic resistance in enterococci is the first step for devising strategies to control the spread of these organisms and potentially establish novel therapeutic approaches.

  7. Development and application of the active surveillance of pathogens microarray to monitor bacterial gene flux

    Directory of Open Access Journals (Sweden)

    Hinds Jason

    2008-10-01

    Full Text Available Abstract Background Human and animal health is constantly under threat by emerging pathogens that have recently acquired genetic determinants that enhance their survival, transmissibility and virulence. We describe the construction and development of an Active Surveillance of Pathogens (ASP oligonucleotide microarray, designed to 'actively survey' the genome of a given bacterial pathogen for virulence-associated genes. Results The microarray consists of 4958 reporters from 151 bacterial species and include genes for the identification of individual bacterial species as well as mobile genetic elements (transposons, plasmid and phage, virulence genes and antibiotic resistance genes. The ASP microarray was validated with nineteen bacterial pathogens species, including Francisella tularensis, Clostridium difficile, Staphylococcus aureus, Enterococcus faecium and Stenotrophomonas maltophilia. The ASP microarray identified these bacteria, and provided information on potential antibiotic resistance (eg sufamethoxazole resistance and sulfonamide resistance and virulence determinants including genes likely to be acquired by horizontal gene transfer (e.g. an alpha-haemolysin. Conclusion The ASP microarray has potential in the clinic as a diagnostic tool, as a research tool for both known and emerging pathogens, and as an early warning system for pathogenic bacteria that have been recently modified either naturally or deliberately.

  8. A novel approach to eliminate Wolbachia infections in Nasonia vitripennis revealed different antibiotic resistance between two bacterial strains.

    Science.gov (United States)

    Liu, Hai-Yang; Wang, Yan-Kun; Zhi, Cong-Cong; Xiao, Jin-Hua; Huang, Da-Wei

    2014-06-01

    Wolbachia are widespread in insects and can manipulate host reproduction. Nasonia vitripennis is a widely studied organism with a very high prevalence of Wolbachia infection. To study the effect of Wolbachia infection in Nasonia spp., it is important to obtain noninfected individuals by artificial methods. Current methods that employ sugar water-containing antibiotics can successfully eliminate Wolbachia from the parasitic wasps; however, treatment of at least three generations is required. Here, we describe a novel, feasible, and effective approach to eliminate Wolbachia from N. vitripennis by feeding fly pupae continuously offering antibiotics to Nasonia populations, which shortened the time to eliminate the pathogens to two generations. Additionally, the Wolbachia Uni and CauB strains have obviously different rifampicin-resistance abilities, which is a previously unknown phenomenon.

  9. Distribution and Antibiotic Resistance of Pathogenic Bacteria of Lower Respiratory Tract Infections in Gerontal Patients%老年患者下呼吸道感染的病原菌分布及其耐药性分析

    Institute of Scientific and Technical Information of China (English)

    李红丽

    2011-01-01

    Objective To review the distribution and drug resistance of pathogens in nosocomial lower respiratory tract infections among 241 gerontal patients to provide reference for rational use of antimicrobial agents. Methods Sputum samples were collected from 687 hospitalized gerontal patients with lower respiratory tract infections. Pathogens were isolated from the sputum samples and bacterial rapid test kit and relevant software were applied to identify the types and antibiotic resistance of the pathogens. Results A total of 241 strains of pathogenic bacteria were isolated from the 687 patients ( detection rate : 35.1% ).Of these strains, 165 were Gram - negative bacillus ( 68.5% ), 35 were Gram - positive cocci ( 14.5% ) and 41 were fungi ( 17.0% ). The top three Gram - negative bacilli were Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa.The top three Gram - positive cocci were Staphylococcus aureus, Staphylococcus haemolyticus and Staphylococcus epidermidis.Analysis of drug resistance showed that imipenem resistance rates of the three Gram - negative bacteria were the lowest, while ampicillin and ofloxacin resistance rates were the highest. The resistance rate of staphylococcus to penicillium was 100% . Staphylococcus was sensitive to vancomycin, imipenem and teicoplanin. Conclusion Gram - negative bacteria are the main pathogens of lower respiratory tract infections among gerontal patients, with Klebsiella pneumonia most commonly seen. Pathogen detection and drug resistance monitoring should be enhanced with the hope to promote the rational use of antimicrobial agents and to slow down the emergence of antibiotic - resistant strains.%目的 分析我院老年患者下呼吸道感染病原菌的分布及其耐药情况,为临床合理选用抗菌药物提供科学的依据.方法 收集687例老年下呼吸道感染患者的痰液标本进行细菌培养,分离病原菌,用珠海迪尔试剂盒及分析软件进行细菌鉴

  10. Isolated cell behavior drives the evolution of antibiotic resistance.

    Science.gov (United States)

    Artemova, Tatiana; Gerardin, Ylaine; Dudley, Carmel; Vega, Nicole M; Gore, Jeff

    2015-07-29

    Bacterial antibiotic resistance is typically quantified by the minimum inhibitory concentration (MIC), which is defined as the minimal concentration of antibiotic that inhibits bacterial growth starting from a standard cell density. However, when antibiotic resistance is mediated by degradation, the collective inactivation of antibiotic by the bacterial population can cause the measured MIC to depend strongly on the initial cell density. In cases where this inoculum effect is strong, the relationship between MIC and bacterial fitness in the antibiotic is not well defined. Here, we demonstrate that the resistance of a single, isolated cell-which we call the single-cell MIC (scMIC)-provides a superior metric for quantifying antibiotic resistance. Unlike the MIC, we find that the scMIC predicts the direction of selection and also specifies the antibiotic concentration at which selection begins to favor new mutants. Understanding the cooperative nature of bacterial growth in antibiotics is therefore essential in predicting the evolution of antibiotic resistance.

  11. 烧伤病房病原菌耐药性的变迁%Vicissitude of antibiotics resistance of pathogens in a burn unit

    Institute of Scientific and Technical Information of China (English)

    于勇; 盛志勇; 柴家科; 施志国; 常东; 蒋伟

    2001-01-01

    Objective:To analyze the vicissitude of antibiotic resistance of pathogens in a burn unit.Methods:The identification and antibiotics sensitivity test data of bacteria isolated from patients in our burn unit in a 5year period were reviewed,and the average inhibition zone diameter of susceptibility test was calculated.Results:The resistance rate of S.aureus to all 7 antibiotics were higher than 30%,but resistance rate of P.aeruginosa,E.coli,Serratia and Enterobacter to most of the antibiotics used in this unit were lower than 30%.The resistance rate of bacteria were negatively correlated markedly with average inhibition zone diameter of sensetivity test.Conclusions:S.aureus is the most resistant bacteria to antibiotics among burn infection pathogens.In addition,the change in average inhibition zone diameter may reflect the vicissitude of resistance to antibiotics in pathogens.%目的:对烧伤病房病原菌耐药性的变化进行研究。方法:对1994年12月~1999年11月5年我院烧伤病房病原菌分离、鉴定及药敏试验资料进行统计分析。结果:金黄色葡萄球菌(金葡菌)对6种抗生素的耐药率均超过30%;铜绿假单胞菌、大肠杆菌、沙雷氏菌属的耐药率相对较低,对多种抗生素的耐药率低于30%。试验菌株对大部分抗生素的耐药率在1997年后均有不同程度的下降。病原菌耐药率的变化与药敏试验平均抑菌环直径的变化呈高度负相关。结论:金葡菌是烧伤感染病原菌中耐药性最强的细菌。药敏试验平均抑菌环直径的变化可以在一定程度上反映病原菌耐药性的变化。

  12. Antibiotic resistance: current issues and future strategies

    Directory of Open Access Journals (Sweden)

    Giancarlo Scarafile

    2016-09-01

    Full Text Available The antibiotic resistance (antimicrobial resistance – AMR and the particular emergence of multi-resistant bacterial strains, is a problem of clinical relevance involving serious threats to public health worldwide. From early this decade, a lot of studies have demonstrated a significant increase in the rates of antibiotic resistance by bacterial pathogens responsible for nosocomial and community infections all over the world. The AMR leads to a reduced drug efficacy in the treatment options available and therefore, to an increase in mortality rates. The original causes of the phenomenon are: environmental factors which favor a mutation of the genetic bacterial inheritance, thereby inhibiting the active ingredient of the antibiotics; unsuitable administering of antibiotics in veterinary, incorrect taking both in hospitals and at home and, lately, lack of investments in the development of new drugs. The alarming epidemiological data prompted the World Health Organization (WHO in 2011 to coin the slogan "No action today, no cure tomorrow" in order to immediately implement a new strategy to improve the use of available drugs and to accelerate the introduction of new ones through a new phase of research involving private and public institutions. The European Union has stressed that the surveillance is considered an essential factor for an effective response to this problem but it has also highlighted that the results produced have been lower than expectations because of serious shortcomings such as lack of methodological standards, insufficient data sharing and no coordination among European countries. In Italy the situation is much more troubling; in fact, according to the Ministry of Health, 5000-7000 yearly deaths are deemed due to nosocomial infections, with an annual cost of more than 100 million €.These figures explain how the fight against infections is far from being won. The purpose of this review is to analyze the basic causes of the

  13. Genotypic Detection of Antibiotic Resistance in "Escherichia Coli.": A Classroom Exercise

    Science.gov (United States)

    Longtin, Sarah; Guilfoile, Patrick; Asper, Andrea

    2004-01-01

    Bacterial antibiotic resistance remains a problem of clinical importance. Current microbiological methods for determining antibiotic resistance are based on culturing bacteria, and may require up to 48 hours to complete. Molecular methods are increasingly being developed to speed the identification of antibiotic resistance and to determine its…

  14. Antibiotic resistance patterns of major zoonotic pathogens from all-natural, antibiotic-free, pasture-raised broiler flocks in the southeastern United States

    Science.gov (United States)

    The use of antibiotics in agroecosystems has been implicated in the rise in antibiotic resistance that can affect environmental, animal, and human health. In order to effectively determine the environmental impact of antibiotic use in agroecosystems, appropriate background levels of antibiotic resi...

  15. Emergence and dissemination of antibiotic resistance: A global problem

    Directory of Open Access Journals (Sweden)

    R Choudhury

    2012-01-01

    Full Text Available Antibiotic resistance is a major problem in clinical health settings. Interestingly the origin of many of antibiotic resistance mechanisms can be traced back to non-pathogenic environmental organisms. Important factors leading to the emergence and spread of antibiotic resistance include absence of regulation in the use of antibiotics, improper waste disposal and associated transmission of antibiotic resistance genes in the community through commensals. In this review, we discussed the impact of globalisation on the transmission of antibiotic resistance genes in bacteria through immigration and export/import of foodstuff. The significance of surveillance to define appropriate use of antibiotics in the clinic has been included as an important preventive measure.

  16. Molecular mechanisms of bacterial persistence and phenotypic antibiotic resistance%细菌持留与抗生素表型耐药机制

    Institute of Scientific and Technical Information of China (English)

    崔鹏; 许涛; 张文宏; 张颖

    2016-01-01

    Bacterial persistence refers to a state of reduced metabolic activity that endows a subpopulation of isogenic bacteria with multidrug tolerance. Persisters are phenotypic variants but not mutants. Since its discovery in 1944, bacterial persistence has not received enough attention until recently when its implications in persistent infections and biofilm infections become apparent. Much research has been done in recent years to investigate the mechanisms underlying bacterial persistence and phenotypic antibiotic resistance. The mechanisms of bacterial persistence are complex and the following pathways are involved in persister formation: toxin-antitoxin systems, reduced metabolism, energy production, protein and nucleic acid synthesis, DNA repair and protection, protein degradation, transporters/efflux systems, and transcriptional regulators etc. Although persistence mechanisms are conserved in terms of the gene function and pathways involved among different bacterial species, they may vary in gene homology and relative importance of a given pathway. For example, Escherichia coli toxin-antitoxin systems play an important role in persister formation, while Staphylococcus aureus persister formation does not appear to use toxin-antitoxin systems. Here we provide an update on recent progress in persistence mechanisms using E. coli and S. aureus as models, as well as discuss approaches in the treatment of persistent bacterial infections.%持留菌是细菌群体中一小部分具有表型耐药的细菌。自1944年被发现后,近几十年来因其在慢性持续性感染和生物膜感染中的重要作用而得到越来越多的重视。已有的研究结果表明,细菌持留的机理复杂,涉及的相关信号通路有毒素-抗毒素系统、细胞能量代谢及蛋白核酸合成等生理状态的降低、DNA保护修复系统、蛋白酶系统、反式翻译、外排泵系统等。虽然不同细菌的持留机理有一定的相似性和保守性,但

  17. Antibiotic resistance of bacterial biofilms

    DEFF Research Database (Denmark)

    Hoiby, N.; Bjarnsholt, T.; Givskov, M.

    2010-01-01

    and other components of the body's defence system. The persistence of, for example, staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is caused by biofilm-growing mucoid strains...... to antibiotics. Biofilm growth is associated with an increased level of mutations as well as with quorum-sensing-regulated mechanisms. Conventional resistance mechanisms such as chromosomal beta-lactamase, upregulated efflux pumps and mutations in antibiotic target molecules in bacteria also contribute...

  18. Probiotic approach to prevent antibiotic resistance.

    Science.gov (United States)

    Ouwehand, Arthur C; Forssten, Sofia; Hibberd, Ashley A; Lyra, Anna; Stahl, Buffy

    2016-01-01

    Probiotics are live microorganisms, mainly belonging to the genera Lactobacillus and Bifidobacterium, although also strain of other species are commercialized, that have a beneficial effect on the host. From the perspective of antibiotic use, probiotics have been observed to reduce the risk of certain infectious disease such as certain types of diarrhea and respiratory tract infection. This may be accompanied with a reduced need of antibiotics for secondary infections. Antibiotics tend to be effective against most common diseases, but increasingly resistance is being observed among pathogens. Probiotics are specifically selected to not contribute to the spread of antibiotic resistance and not carry transferable antibiotic resistance. Concomitant use of probiotics with antibiotics has been observed to reduce the incidence, duration and/or severity of antibiotic-associated diarrhea. This contributes to better adherence to the antibiotic prescription and thereby reduces the evolution of resistance. To what extent probiotics directly reduce the spread of antibiotic resistance is still much under investigation; but maintaining a balanced microbiota during antibiotic use may certainly provide opportunities for reducing the spread of resistances. Key messages Probiotics may reduce the risk for certain infectious diseases and thereby reduce the need for antibiotics. Probiotics may reduce the risk for antibiotic-associated diarrhea Probiotics do not contribute to the spread of antibiotic resistance and may even reduce it.

  19. 613株病原菌分布及其主要耐药情况分析%Distribution of 613 Strains of Pathogenic Bacteria and Antibiotic Resistance of the Main Pathogenic Bacteria analysis

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Objective To analyze the distribution of pathogenic bacteria isolated from our hospital and the antibiotic resistance of the main pathogenic bacteria ,to provide a basis for clinical rational drug use and control the hospital infection .Methods 613 strains of pathogenic bacteria separated from patients in our hospital during June to December of 2012 were identifited by Hengxing bacteria analysis and detected the antibiotic resistance by Kirby-Bauer(K-B) agar tapediffusion. Results We gather 613 strains in last year of 2012,there were 417 strains Gram-negative bacteria (68%),128 strains Gram-positive bacteria(20.8%),and 68 strains fungi(13.2%), obviously the antibiotic resistance of pathogenic bacteria was higer than first half year.Conclusion It is necessary to reasonably use antibiotics,strengthen the awareness of bacteria culture and strictly comply the standards of diagnosis and antibiotic use so as to prevent the antibiotic resistanc of pathogenic bacteria. Gram-negative bacteria was the main pathogenic bacteria,clinician should ware the infection of Gram-negative bacteria.%  目的分析故城县医院检出的病原菌分布及其主要病原菌的耐药情况,为临床合理用药和控制医院感染提供参考。方法采用恒星细菌分析系统对2012年6月至2012年12月分离的613株病原菌进行鉴定,药敏试验采用琼脂纸片扩散法。结果2012年下半年共收集非重复临床分离菌株613株,其中革兰阴性菌417株占68%,革兰阳性菌128株占20.8%,真菌68株占11.2%,除真菌外其他病原菌的耐药率较之上半年都明显增加。结论应完善抗菌药物的规范使用,加强细菌培养意识,严格控制医院感染病例的诊断和用药标准,预防抗菌药物耐药率的快速产生。革兰阴性杆菌在住院患者感染中占主要地位,临床医师应警惕革兰阴性菌引起的感染。

  20. Investigating the Antibiotic Resistance Problem.

    Science.gov (United States)

    Lawson, Michael; Lawson, Amy L.

    1998-01-01

    Seeks to give teachers useful information on the extent of the problem of antibiotic-resistant bacteria, mechanisms bacteria use to resist antibiotics, the causes of the emergence of antibiotic-resistant organisms, and practices that can prevent or reverse this trend. Contains 19 references. (DDR)

  1. REDUCTION OF ANTIBIOTIC RESISTANCE IN BACTERIA: A REVIEW

    Directory of Open Access Journals (Sweden)

    Suresh Jaiswal et al.

    2012-03-01

    Full Text Available Drug resistant bacteria have been posing a major challenge to the effective control of bacterial infections for quite some time. One of the main causes of antibiotics drug resistance is antibiotic overuse, abuse, and in some cases, misuse, due to incorrect diagnosis. Bacterial antibiotic resistance is a significant issues faced by various industries, including the food and agricultural industries, the medical and veterinary profession and others. The potential for transfer of antibiotics resistance, or of potentially lethal antibiotic resistant bacteria, for example from a food animal to human consumer, is of particular concern. A method of controlling development and spread of antibiotic-resistant bacteria include changes in antibiotic usage and pattern of usage of different antibiotics. However, the ability of bacteria to adapt to antibiotic usage and to acquire resistance to existing and new antibiotics usage overcomes such conventional measures, and requires the continued development of alternative means of control of antibiotic resistance bacteria. Alternative means for overcoming the tendency of bacteria to acquire resistance to antibiotic control measures have taken various forms. This article explains one method evaluated for control, that is reducing or removing antibiotic resistance is so called “curing” of antibiotic resistance. Antibiotic resistance is formed in the chromosomal elements. Thus elimination of such drug-resistance plasmids results in loss of antibiotics resistance by the bacterial cell. “Curing” of a microorganism refers to the ability of the organism to spontaneously lose a resistance plasmid under the effect of particular compounds and environmental conditions, thus recovering the antibiotic sensitive state.

  2. Emergence and spread of antibiotic resistance: setting a parameter space.

    Science.gov (United States)

    Martínez, José Luis; Baquero, Fernando

    2014-05-01

    The emergence and spread of antibiotic resistance among human pathogens is a relevant problem for human health and one of the few evolution processes amenable to experimental studies. In the present review, we discuss some basic aspects of antibiotic resistance, including mechanisms of resistance, origin of resistance genes, and bottlenecks that modulate the acquisition and spread of antibiotic resistance among human pathogens. In addition, we analyse several parameters that modulate the evolution landscape of antibiotic resistance. Learning why some resistance mechanisms emerge but do not evolve after a first burst, whereas others can spread over the entire world very rapidly, mimicking a chain reaction, is important for predicting the evolution, and relevance for human health, of a given mechanism of resistance. Because of this, we propose that the emergence and spread of antibiotic resistance can only be understood in a multi-parameter space. Measuring the effect on antibiotic resistance of parameters such as contact rates, transfer rates, integration rates, replication rates, diversification rates, and selection rates, for different genes and organisms, growing under different conditions in distinct ecosystems, will allow for a better prediction of antibiotic resistance and possibilities of focused interventions.

  3. Antibiotic resistance rates in causative agents of infections in diabetic patients: rising concerns.

    Science.gov (United States)

    Boyanova, Lyudmila; Mitov, Ivan

    2013-04-01

    The vicious cycle is that hyperglycemia (≥11.1 mmol/l) or other diabetes-associated factors facilitate or worsen the development of infections and vice versa, the infections deteriorate the glycemic control of the patients. Diabetic patients are prone to some infections, infection recurrences and poor outcomes. Immunocompromised state and frequent antibiotic use are associated with antibiotic resistance of the bacterial pathogens, such as Mycobacterium tuberculosis (in some studies), methicillin-resistant Staphylococcus aureus, Streptococcus pneumoniae, Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii, bacteria in diabetic foot infections and different opportunistic and rare pathogens or multidrug-resistant strains. Prompt diagnostics and susceptibility testing, early and aggressive surgical and/or antibiotic therapy, and, importantly, good glycemic control are of utmost importance for treatment of antibiotic-resistant infections in diabetic patients.

  4. Disruption of the Gut Microbiome: Clostridium difficile Infection and the Threat of Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    Priscilla A. Johanesen

    2015-12-01

    Full Text Available Clostridium difficile is well recognized as the leading cause of antibiotic-associated diarrhea, having a significant impact in both health-care and community settings. Central to predisposition to C. difficile infection is disruption of the gut microbiome by antibiotics. Being a Gram-positive anaerobe, C. difficile is intrinsically resistant to a number of antibiotics. Mobile elements encoding antibiotic resistance determinants have also been characterized in this pathogen. While resistance to antibiotics currently used to treat C. difficile infection has not yet been detected, it may be only a matter of time before this occurs, as has been seen with other bacterial pathogens. This review will discuss C. difficile disease pathogenesis, the impact of antibiotic use on inducing disease susceptibility, and the role of antibiotic resistance and mobile elements in C. difficile epidemiology.

  5. Antibiotic resistance gene discovery in food-producing animals.

    Science.gov (United States)

    Allen, Heather K

    2014-06-01

    Numerous environmental reservoirs contribute to the widespread antibiotic resistance problem in human pathogens. One environmental reservoir of particular importance is the intestinal bacteria of food-producing animals. In this review I examine recent discoveries of antibiotic resistance genes in agricultural animals. Two types of antibiotic resistance gene discoveries will be discussed: the use of classic microbiological and molecular techniques, such as culturing and PCR, to identify known genes not previously reported in animals; and the application of high-throughput technologies, such as metagenomics, to identify novel genes and gene transfer mechanisms. These discoveries confirm that antibiotics should be limited to prudent uses.

  6. Bacterial pathogens in rainbow trout, Oncorhynchus mykiss (Walbaum), reared at Danish freshwater farms

    DEFF Research Database (Denmark)

    Dalsgaard, Inger; Madsen, Lone

    2000-01-01

    During a 2-year period, bacterial fish pathogens were monitored on five rainbow trout, Oncorhynchus mykirs (Walbaum), freshwater farms in Denmark. A total of 1206 fish were examined and 361 bacterial isolates were identified phenotypically. Enteric redmouth disease, furunculosis and rainbow trout....... psychrophilum isolates showed resistance to oxolinic acid and oxytetracycline. No antibiotic resistant isolates were found among Y. ruckeri and A. salmonicida.......During a 2-year period, bacterial fish pathogens were monitored on five rainbow trout, Oncorhynchus mykirs (Walbaum), freshwater farms in Denmark. A total of 1206 fish were examined and 361 bacterial isolates were identified phenotypically. Enteric redmouth disease, furunculosis and rainbow trout...... of fry and larger fish. All isolates of F. psychrophilum showed proteolytic activities; however, a few isolates, belonging to serotype Fp(T) did not degrade elastin and were not associated with mortality. Increasing resistance problems to oxytetracycline were demonstrated. More than half of the F...

  7. Tracking acquired antibiotic resistance in commensal bacteria of Galapagos land iguanas: no man, no resistance.

    Directory of Open Access Journals (Sweden)

    Maria Cristina Thaller

    Full Text Available BACKGROUND: Antibiotic resistance, evolving and spreading among bacterial pathogens, poses a serious threat to human health. Antibiotic use for clinical, veterinary and agricultural practices provides the major selective pressure for emergence and persistence of acquired resistance determinants. However, resistance has also been found in the absence of antibiotic exposure, such as in bacteria from wildlife, raising a question about the mechanisms of emergence and persistence of resistant strains under similar conditions, and the implications for resistance control strategies. Since previous studies yielded some contrasting results, possibly due to differences in the ecological landscapes of the studied wildlife, we further investigated this issue in wildlife from a remote setting of the Galapagos archipelago. METHODOLOGY/PRINCIPAL FINDINGS: Screening for acquired antibiotic resistance was carried out in commensal enterobacteria from Conolophus pallidus, the terrestrial iguana of Isla Santa Fe, where: i the abiotic conditions ensure to microbes good survival possibilities in the environment; ii the animal density and their habits favour microbial circulation between individuals; and iii there is no history of antibiotic exposure and the impact of humans and introduced animal species is minimal except for restricted areas. Results revealed that acquired antibiotic resistance traits were exceedingly rare among bacteria, occurring only as non-dominant strains from an area of minor human impact. CONCLUSIONS/SIGNIFICANCE: Where both the exposure to antibiotics and the anthropic pressure are minimal, acquired antibiotic resistance traits are not normally found in bacteria from wildlife, even if the ecological landscape is highly favourable to bacterial circulation among animals. Monitoring antibiotic resistance in wildlife from remote areas could also be a useful tool to evaluate the impact of anthropic pressure.

  8. Relation between bacterial efflux pump and antibiotic resistance%细菌外排泵与抗生素耐药的相关性

    Institute of Scientific and Technical Information of China (English)

    孙渊; 查伟斌; 周芳; 吴晓兰; 张经纬; 王广基

    2012-01-01

    抗生素耐药与临床用药紧密相关,一直以来都受到广泛关注.除了药物失活、靶点改变这些已经熟知的耐药机制以外,细菌外排泵的作用也是抗生素耐药的重要原因.外排泵在细菌中普遍存在并且底物十分广泛,其表达对多种细菌的先天耐药和后天耐药都有贡献.对于金黄色葡萄球菌、大肠杆菌、绿脓杆菌等细菌,外排泵导致的耐药是其耐药的主要原因,因此在临床用药过程中,外排泵产生的耐药成了不可忽略的因素.这也给新药研发提供了新的思路,已经有研究以外排泵为靶点开发新药,而开发能够规避外排泵作用的新型抗生素也是克服外排泵耐药的一个途径.本文从分类,结构,调控以及抑制剂等方面对近年来细菌外排转运体方面的研究进行综述,为进一步的探索提供参考.%Drug resistance in bacteria has attracted much attention in clinical antibacterial therapy for years. In addition to the well known mechanisms, such as inactivation of drugs and alteration of targets, drug extruding pumps also play a major role in resistance to antibacterials. Efflux pumps are widespread in bacteria and have broad variety of substrates. Their presence contributes both intrinsic and acquired bacterial resistance. Efflux-mediated drug-resistance has been recognized as the major mechanism of resistance to antibacterial agents in Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The impact of antibiotic efflux pumps on therapy must be taken fully into ac- count for the selection of antimicrobials. The design of specific, potent inhibitors appears to be an important goal for the improved control of infectious diseases in the near future. An alternative approach is to develop antibacterials that would bypass the action of efflux pumps. This paper will review recent progress on the role of bacterial efflux transporters in antibiotic resistance from the aspects of classification

  9. Effective Antibiotic Resistance Mitigation during Cheese Fermentation ▿

    OpenAIRE

    Li, Xinhui; Li, Yingli; Alvarez, Valente; Harper, Willis James; Wang, Hua H.

    2011-01-01

    Controlling antibiotic-resistant (ART) bacteria in cheese fermentation is important for food safety and public health. A plant-maintained culture was found to be a potential source for ART bacterial contamination in cheese fermentation. Antibiotics had a detectable effect on the ART population from contamination in the finished product. The decrease in the prevalence of antibiotic resistance (AR) in retail cheese samples from 2010 compared to data from 2006 suggested the effectiveness of targ...

  10. Antigenic Variation in Bacterial Pathogens.

    Science.gov (United States)

    Palmer, Guy H; Bankhead, Troy; Seifert, H Steven

    2016-02-01

    Antigenic variation is a strategy used by a broad diversity of microbial pathogens to persist within the mammalian host. Whereas viruses make use of a minimal proofreading capacity combined with large amounts of progeny to use random mutation for variant generation, antigenically variant bacteria have evolved mechanisms which use a stable genome, which aids in protecting the fitness of the progeny. Here, three well-characterized and highly antigenically variant bacterial pathogens are discussed: Anaplasma, Borrelia, and Neisseria. These three pathogens display a variety of mechanisms used to create the structural and antigenic variation needed for immune escape and long-term persistence. Intrahost antigenic variation is the focus; however, the role of these immune escape mechanisms at the population level is also presented.

  11. Influence of two-phase anaerobic digestion on fate of selected antibiotic resistance genes and class I integrons in municipal wastewater sludge

    DEFF Research Database (Denmark)

    Wu, Ying; Cui, Erping; Zuo, Yiru

    2016-01-01

    The response of representative antibiotic resistance genes (ARGs) to lab-scale two-phase (acidogenic/methanogenic phase) anaerobic digestion processes under thermophilic and mesophilic conditions was explored. The associated microbial communities and bacterial pathogens were characterized by 16S r...

  12. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    KAUST Repository

    Hong, Pei-Ying

    2013-07-31

    Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  13. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes.

    Science.gov (United States)

    Hong, Pei-Ying; Al-Jassim, Nada; Ansari, Mohd Ikram; Mackie, Roderick I

    2013-07-31

    Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the "perfect microbial storm". Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  14. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    Directory of Open Access Journals (Sweden)

    Roderick I. Mackie

    2013-07-01

    Full Text Available Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  15. Antibiotic Resistance Questions and Answers

    Science.gov (United States)

    ... on the Farm Get Smart About Antibiotics Week Antibiotic Resistance Questions and Answers Language: English Español (Spanish) ... a los antibióticos Questions about Bacteria, Viruses, and Antibiotics Q: What are bacteria and viruses? A: Bacteria ...

  16. Characterization of bacterial pathogens in rural and urban irrigation water.

    Science.gov (United States)

    Aijuka, Matthew; Charimba, George; Hugo, Celia J; Buys, Elna M

    2015-03-01

    The study aimed to compare the bacteriological quality of an urban and rural irrigation water source. Bacterial counts, characterization, identification and diversity of aerobic bacteria were determined. Escherichia coli isolated from both sites was subjected to antibiotic susceptibility testing, virulence gene (Stx1/Stx2 and eae) determination and (GTG)5 Rep-PCR fingerprinting. Low mean monthly counts for aerobic spore formers, anaerobic spore formers and Staphylococcus aureus were noted although occasional spikes were observed. The most prevalent bacterial species at both sites were Bacillus spp., E. coli and Enterobacter spp. In addition, E. coli and Bacillus spp. were most prevalent in winter and summer respectively. Resistance to at least one antibiotic was 84% (rural) and 83% (urban). Highest resistance at both sites was to cephalothin and ampicillin. Prevalence of E. coli possessing at least one virulence gene (Stx1/Stx2 and eae) was 15% (rural) and 42% (urban). All (rural) and 80% (urban) of E. coli possessing virulence genes showed antibiotic resistance. Complete genetic relatedness (100%) was shown by 47% of rural and 67% of urban E. coli isolates. Results from this study show that surface irrigation water sources regardless of geographical location and surrounding land-use practices can be reservoirs of similar bacterial pathogens.

  17. 表观遗传和蛋白质翻译后修饰在细菌耐药中的作用%The roles of epigenetics and protein post-translational modifications in bacterial antibiotic resistance

    Institute of Scientific and Technical Information of China (English)

    谢龙祥; 于召箫; 郭思瑶; 李萍; Abualgasim Elgaili Abdall; 谢建平

    2015-01-01

    The increasing antibiotic resistance is now threatening to take us back to a pre-antibiotic era. Bacteria have evolved diverse resistance mechanisms, on which in-depth research could help the development of new strate-gies to control antibiotic-resistant infections. Epigenetic alterations and protein post-translational modifications (PTMs) play important roles in multiple cellular processes such as metabolism, signal transduction, protein degrada-tion, DNA replication regulation and stress response. Recent studies demonstrated that epigenetics and PTMs also play vital roles in bacterial antibiotic resistance. In this review, we summarize the regulatory roles of epigenetic fac-tors including DNA methylation and regulatory RNAs as well as PTMs such as phosphorylation and succinylation in bacterial antibiotic resistance, which may provide innovative perspectives on selecting antibacterial targets and developing antibiotics.%日益严重的细菌耐药性有可能使人类重回前抗生素时代。细菌的耐药机理多样,深入研究细菌的耐药性形成机理有助于开发控制耐药细菌感染的新措施。表观遗传和蛋白质翻译后修饰在细胞代谢、信号转导、蛋白质降解、调控DNA复制、应激反应等方面都具有重要作用。近年来研究表明表观遗传和蛋白质翻译后修饰在细菌耐药中也扮演着重要的角色。本文总结了DNA甲基化、调控型RNAs等表观遗传因素和磷酸化、琥珀酰基化等蛋白质翻译后修饰因素在细菌耐药性中的调控作用,以期为抗生素靶标选择和抗生素开发设计提供新思路。

  18. Multidrug efflux pumps in Gram-negative bacteria and their role in antibiotic resistance.

    Science.gov (United States)

    Blair, Jessica M A; Richmond, Grace E; Piddock, Laura J V

    2014-01-01

    Gram-negative bacteria express a plethora of efflux pumps that are capable of transporting structurally varied molecules, including antibiotics, out of the bacterial cell. This efflux lowers the intracellular antibiotic concentration, allowing bacteria to survive at higher antibiotic concentrations. Overexpression of some efflux pumps can cause clinically relevant levels of antibiotic resistance in Gram-negative pathogens. This review discusses the role of efflux in resistance of clinical isolates of Gram-negative bacteria, the regulatory mechanisms that control efflux pump expression, the recent advances in our understanding of efflux pump structure and how inhibition of efflux is a promising future strategy for tackling multidrug resistance in Gram-negative pathogens.

  19. Integron involvement in environmental spread of antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Thibault eStalder

    2012-04-01

    Full Text Available The spread of antibiotic-resistant bacteria is a growing problem and a public health issue. In recent decades, various genetic mechanisms involved in the spread of resistance genes among bacteria have been identified. Integrons -- genetic elements that acquire, exchange and express genes embedded within gene cassettes (GC -- are one of these mechanisms. Integrons are widely distributed, especially in Gram-negative bacteria; they are carried by mobile genetic elements, plasmids and transposons, which promote their spread within bacterial communities. Initially studied mainly in the clinical setting for their involvement in antibiotic resistance, their role in the environment is now an increasing focus of attention. The aim of this review is to provide an in-depth analysis of recent studies of antibiotic-resistance integrons in the environment, highlighting their potential involvement in antibiotic resistance outside the clinical context. We will focus particularly on the impact of human activities (agriculture, industries, wastewater treatment, etc..

  20. Antibiotic resistance in the wild: an eco-evolutionary perspective

    Science.gov (United States)

    Virta, Marko

    2017-01-01

    The legacy of the use and misuse of antibiotics in recent decades has left us with a global public health crisis: antibiotic-resistant bacteria are on the rise, making it harder to treat infections. At the same time, evolution of antibiotic resistance is probably the best-documented case of contemporary evolution. To date, research on antibiotic resistance has largely ignored the complexity of interactions that bacteria engage in. However, in natural populations, bacteria interact with other species; for example, competition and grazing are import interactions influencing bacterial population dynamics. Furthermore, antibiotic leakage to natural environments can radically alter bacterial communities. Overall, we argue that eco-evolutionary feedback loops in microbial communities can be modified by residual antibiotics and evolution of antibiotic resistance. The aim of this review is to connect some of the well-established key concepts in evolutionary biology and recent advances in the study of eco-evolutionary dynamics to research on antibiotic resistance. We also identify some key knowledge gaps related to eco-evolutionary dynamics of antibiotic resistance, and review some of the recent technical advantages in molecular microbiology that offer new opportunities for tackling these questions. Finally, we argue that using the full potential of evolutionary theory and active communication across the different fields is needed for solving this global crisis more efficiently. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences'. PMID:27920384

  1. Antibiotic Resistance of Diverse Bacteria from Aquaculture in Borneo

    Science.gov (United States)

    Kathleen, M. M.; Felecia, C.; Reagan, E. L.; Kasing, A.; Lesley, M.; Toh, S. C.

    2016-01-01

    The administration of antimicrobials in aquaculture provides a selective pressure creating a reservoir of multiple resistant bacteria in the cultured fish and shrimps as well as the aquaculture environment. The objective of this study was to determine the extent of antibiotic resistance in aquaculture products and aquaculture's surrounding environment in Sarawak, Malaysian Borneo. Ninety-four identified bacterial isolates constituted of 17 genera were isolated from sediment, water, and cultured organisms (fish and shrimp) in selected aquaculture farms. These isolates were tested for their antibiotic resistance against 22 antibiotics from several groups using the disk diffusion method. The results show that the highest resistance was observed towards streptomycin (85%, n = 20), while the lowest resistance was towards gentamicin (1.1%, n = 90). The multiple antibiotic resistant (MAR) index of the isolates tested ranged between 0 and 0.63. It was suggested that isolates with MAR index > 0.2 were recovered from sources with high risk of antibiotic resistant contamination. This study revealed low level of antibiotic resistance in the aquaculture bacterial isolates except for streptomycin and ampicillin (>50% resistance, n = 94) which have been used in the aquaculture industry for several decades. Antibiotic resistant patterns should be continuously monitored to predict the emergence and widespread of MAR. Effective action is needed to keep the new resistance from further developing and spreading.

  2. Term-seq reveals abundant ribo-regulation of antibiotics resistance in bacteria.

    Science.gov (United States)

    Dar, Daniel; Shamir, Maya; Mellin, J R; Koutero, Mikael; Stern-Ginossar, Noam; Cossart, Pascale; Sorek, Rotem

    2016-04-01

    Riboswitches and attenuators are cis-regulatory RNA elements, most of which control bacterial gene expression via metabolite-mediated, premature transcription termination. We developed an unbiased experimental approach for genome-wide discovery of such ribo-regulators in bacteria. We also devised an experimental platform that quantitatively measures the in vivo activity of all such regulators in parallel and enables rapid screening for ribo-regulators that respond to metabolites of choice. Using this approach, we detected numerous antibiotic-responsive ribo-regulators that control antibiotic resistance genes in pathogens and in the human microbiome. Studying one such regulator in Listeria monocytogenes revealed an attenuation mechanism mediated by antibiotic-stalled ribosomes. Our results expose broad roles for conditional termination in regulating antibiotic resistance and provide a tool for discovering riboswitches and attenuators that respond to previously unknown ligands.

  3. Assessment of altered binding specificity of bacteriophage for ciprofloxacin-induced antibiotic-resistant Salmonella Typhimurium.

    Science.gov (United States)

    Kim, Jeongjin; Jo, Ara; Ding, Tian; Lee, Hyeon-Yong; Ahn, Juhee

    2016-08-01

    This study describes a new effort toward understanding the interaction mechanisms between antibiotic-resistant Salmonella Typhimurium and phages. The antibiotic susceptibility, β-lactamase activity, bacterial motility, gene expression, and lytic activity were evaluated in ciprofloxacin-induced antibiotic-sensitive Salmonella Typhimurium (ASST(CIP)) and ciprofloxacin-induced antibiotic-resistant S. Typhimurium (ARST(CIP)), which were compared to the wild-type strains (ASST(WT) and ARST(WT)). The MIC values of ampicillin, norfloxacin, chloramphenicol, and tetracycline were significantly increased to > 512, 16, 16, and 256 μg/ml, respectively, in the ARST(CIP). The lowest and highest extracellular lactamase activities were observed in ASST(WT) (6.85 μmol/min/ml) and ARST(CIP) (48.83 μmol/min/ml), respectively. The acrA, lpfE, and hilA genes were significantly upregulated by more than tenfold in both ASST(CIP) and ARST(CIP). The induction of multiple antibiotic resistance resulted from the increased efflux pump activity (AcrAB-TolC). The highest phage adsorption rates were more than 95 % for ASST(WT), ASST(CIP), and ARST(WT), while the lowest adsorption rate was 52 % for ARST(CIP) at 15 min of infection. The least lytic activity of phage was 20 % against the ARST(CIP), followed by ASST(CIP) (30 %). The adsorption rate of phage against ARST(CIP) was 52 % at 15 min of infection, which resulted in the decrease in lytic activity (12 %). Understanding the interaction of phage and bacteria is essential for the practical application of phage to control and detect antibiotic-resistant bacteria. The results provide useful information for understanding the binding specificity of phages for multiple antibiotic-resistant pathogens.

  4. A window of opportunity to control the bacterial pathogen Pseudomonas aeruginosa combining antibiotics and phages.

    Science.gov (United States)

    Torres-Barceló, Clara; Arias-Sánchez, Flor I; Vasse, Marie; Ramsayer, Johan; Kaltz, Oliver; Hochberg, Michael E

    2014-01-01

    The evolution of antibiotic resistance in bacteria is a global concern and the use of bacteriophages alone or in combined therapies is attracting increasing attention as an alternative. Evolutionary theory predicts that the probability of bacterial resistance to both phages and antibiotics will be lower than to either separately, due for example to fitness costs or to trade-offs between phage resistance mechanisms and bacterial growth. In this study, we assess the population impacts of either individual or combined treatments of a bacteriophage and streptomycin on the nosocomial pathogen Pseudomonas aeruginosa. We show that combining phage and antibiotics substantially increases bacterial control compared to either separately, and that there is a specific time delay in antibiotic introduction independent of antibiotic dose, that minimizes both bacterial density and resistance to either antibiotics or phage. These results have implications for optimal combined therapeutic approaches.

  5. Enterobacter aerogenes and Enterobacter cloacae; versatile bacterial pathogens confronting antibiotic treatment.

    Science.gov (United States)

    Davin-Regli, Anne; Pagès, Jean-Marie

    2015-01-01

    Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution.

  6. Campylobacter spp., Salmonella spp., Verocytotoxic Escherichia coli, and Antibiotic Resistance in Indicator Organisms in Wild Cervids

    Directory of Open Access Journals (Sweden)

    Handeland K

    2005-03-01

    Full Text Available Faecal samples were collected, as part of the National Health Surveillance Program for Cervids (HOP in Norway, from wild red deer, roe deer, moose and reindeer during ordinary hunting seasons from 2001 to 2003. Samples from a total of 618 animals were examined for verocytotoxic E. coli (VTEC; 611 animals for Salmonella and 324 animals for Campylobacter. A total of 50 samples were cultivated from each cervid species in order to isolate the indicator bacterial species E. coli and Enterococcus faecalis/E. faecium for antibiotic resistance pattern studies. Salmonella and the potentially human pathogenic verocytotoxic E. coli were not isolated, while Campylobacter jejuni jejuni was found in one roe deer sample only. Antibiotic resistance was found in 13 (7.3% of the 179 E. coli isolates tested, eight of these being resistant against one type of antibiotic only. The proportion of resistant E. coli isolates was higher in wild reindeer (24% than in the other cervids (2.2%. E. faecalis or E. faecium were isolated from 19 of the samples, none of these being reindeer. All the strains isolated were resistant against one (84% or more (16% antibiotics. A total of 14 E. faecalis-strains were resistant to virginiamycin only. The results indicate that the cervid species studied do not constitute an important infectious reservoir for either the human pathogens or the antibiotic resistant microorganisms included in the study.

  7. Occurrence and antibiotic resistance of Vibrio parahaemolyticus from shellfish in Selangor, Malaysia

    Directory of Open Access Journals (Sweden)

    Vengadesh eLetchumanan

    2015-12-01

    Full Text Available High consumer demand for shellfish has led to the need for large-scale, reliable shellfish supply through aquaculture or shellfish farming. However, bacterial infections which can spread rapidly among shellfish poses a major threat to this industry. Shellfish farmers therefore often resort to extensive use of antibiotics, both prophylactically and therapeutically, in order to protect their stocks. The extensive use of antibiotics in aquaculture has been postulated to represent a major contributing factor in the rising incidence of antimicrobial resistant pathogenic bacteria in shellfish. This study aimed to investigate the incidence of pathogenic Vibrio parahaemolyticus and determine the antibiotic resistance profile as well as to perform plasmid curing in order to determine the antibiotic resistance mediation. Based on colony morphology, all 450 samples tested were positive for Vibrio spp; however, tox-R assay showed that only 44.4% (200/450 of these were Vibrio parahaemolyticus. Out of these 200 samples, 6.5% (13/200 were trh-positive while none were tdh-positive. Antibiotic resistance was determined for all Vibrio parahaemolyticus identified against 14 commonly used antibiotics and the multiple antibiotic resistance index (MAR was calculated. The isolates demonstrated high resistance to several antibiotics tested- including second and third-line antibiotics- with 88% resistant to ampicillin, 81% to amikacin ,70.5% to kanamycin, 73% to cefotaxime and 51.5% to ceftazidime. The MAR index ranged from 0.00 to 0.79 with the majority of samples having an index of 0.36 (resistant to 5 antibiotics. Among the 13 trh-positive strains, almost 70% (9/13 demonstrated resistance to 4 or more antibiotics. Plasmid profiling for all Vibrio parahaemolyticus isolates revealed that 86.5% (173/200 contained plasmids - ranging from 1 to 7 plasmids with DNA band sizes ranging from 1.2kb to greater than 10kb. 6/13 of the pathogenic V. pathogenic strains contained

  8. Occurrence and Antibiotic Resistance of Vibrio parahaemolyticus from Shellfish in Selangor, Malaysia.

    Science.gov (United States)

    Letchumanan, Vengadesh; Pusparajah, Priyia; Tan, Loh Teng-Hern; Yin, Wai-Fong; Lee, Learn-Han; Chan, Kok-Gan

    2015-01-01

    High consumer demand for shellfish has led to the need for large-scale, reliable shellfish supply through aquaculture or shellfish farming. However, bacterial infections which can spread rapidly among shellfish poses a major threat to this industry. Shellfish farmers therefore often resort to extensive use of antibiotics, both prophylactically and therapeutically, in order to protect their stocks. The extensive use of antibiotics in aquaculture has been postulated to represent a major contributing factor in the rising incidence of antimicrobial resistant pathogenic bacteria in shellfish. This study aimed to investigate the incidence of pathogenic Vibrio parahaemolyticus and determine the antibiotic resistance profile as well as to perform plasmid curing in order to determine the antibiotic resistance mediation. Based on colony morphology, all 450 samples tested were positive for Vibrio sp; however, tox-R assay showed that only 44.4% (200/450) of these were V. parahaemolyticus. Out of these 200 samples, 6.5% (13/200) were trh-positive while none were tdh-positive. Antibiotic resistance was determined for all V. parahaemolyticus identified against 14 commonly used antibiotics and the multiple antibiotic resistance index (MAR) was calculated. The isolates demonstrated high resistance to several antibiotics tested- including second and third-line antibiotics- with 88% resistant to ampicillin, 81% to amikacin,70.5% to kanamycin, 73% to cefotaxime, and 51.5% to ceftazidime. The MAR index ranged from 0.00 to 0.79 with the majority of samples having an index of 0.36 (resistant to five antibiotics). Among the 13 trh-positive strains, almost 70% (9/13) demonstrated resistance to 4 or more antibiotics. Plasmid profiling for all V. parahaemolyticus isolates revealed that 86.5% (173/200) contained plasmids - ranging from 1 to 7 plasmids with DNA band sizes ranging from 1.2 kb to greater than 10 kb. 6/13 of the pathogenic V. pathogenic strains contained plasmid. After plasmid

  9. Molecular mechanisms of antibiotic resistance.

    Science.gov (United States)

    Blair, Jessica M A; Webber, Mark A; Baylay, Alison J; Ogbolu, David O; Piddock, Laura J V

    2015-01-01

    Antibiotic-resistant bacteria that are difficult or impossible to treat are becoming increasingly common and are causing a global health crisis. Antibiotic resistance is encoded by several genes, many of which can transfer between bacteria. New resistance mechanisms are constantly being described, and new genes and vectors of transmission are identified on a regular basis. This article reviews recent advances in our understanding of the mechanisms by which bacteria are either intrinsically resistant or acquire resistance to antibiotics, including the prevention of access to drug targets, changes in the structure and protection of antibiotic targets and the direct modification or inactivation of antibiotics.

  10. The population genetics of antibiotic resistance: integrating molecular mechanisms and treatment contexts.

    Science.gov (United States)

    MacLean, R Craig; Hall, Alex R; Perron, Gabriel G; Buckling, Angus

    2010-06-01

    Despite efforts from a range of disciplines, our ability to predict and combat the evolution of antibiotic resistance in pathogenic bacteria is limited. This is because resistance evolution involves a complex interplay between the specific drug, bacterial genetics and both natural and treatment ecology. Incorporating details of the molecular mechanisms of drug resistance and ecology into evolutionary models has proved useful in predicting the dynamics of resistance evolution. However, putting these models to practical use will require extensive collaboration between mathematicians, molecular biologists, evolutionary ecologists and clinicians.

  11. Exploring the immediate and long-term impact on bacterial communities in soil amended with animal and urban organic waste fertilizers using pyrosequencing and screening for horizontal transfer of antibiotic resistance.

    Science.gov (United States)

    Riber, Leise; Poulsen, Pernille H B; Al-Soud, Waleed A; Skov Hansen, Lea B; Bergmark, Lasse; Brejnrod, Asker; Norman, Anders; Hansen, Lars H; Magid, Jakob; Sørensen, Søren J

    2014-10-01

    We investigated immediate and long-term effects on bacterial populations of soil amended with cattle manure, sewage sludge or municipal solid waste compost in an ongoing agricultural field trial. Soils were sampled in weeks 0, 3, 9 and 29 after fertilizer application. Pseudomonas isolates were enumerated, and the impact on soil bacterial community structure was investigated using 16S rRNA amplicon pyrosequencing. Bacterial community structure at phylum level remained mostly unaffected. Actinobacteria, Proteobacteria and Chloroflexi were the most prevalent phyla significantly responding to sampling time. Seasonal changes seemed to prevail with decreasing bacterial richness in week 9 followed by a significant increase in week 29 (springtime). The Pseudomonas population richness seemed temporarily affected by fertilizer treatments, especially in sludge- and compost-amended soils. To explain these changes, prevalence of antibiotic- and mercury-resistant pseudomonads was investigated. Fertilizer amendment had a transient impact on the resistance profile of the soil community; abundance of resistant isolates decreased with time after fertilizer application, but persistent strains appeared multiresistant, also in unfertilized soil. Finally, the ability of a P. putida strain to take up resistance genes from indigenous soil bacteria by horizontal gene transfer was present only in week 0, indicating a temporary increase in prevalence of transferable antibiotic resistance genes.

  12. What Can Be Done about Antibiotic Resistance?

    Science.gov (United States)

    ... Us General Background: What can be done about Antibiotic Resistance? What can I do? Are antibacterial agents, such ... regulated? Is there any international action on the antibiotic resistance issue? Can the effectiveness of existing antibiotics be ...

  13. Recent changes in bacteremia in patients with cancer: a systematic review of epidemiology and antibiotic resistance.

    Science.gov (United States)

    Montassier, E; Batard, E; Gastinne, T; Potel, G; de La Cochetière, M F

    2013-07-01

    Bacteremia remains a major cause of life-threatening complication in patients with cancer. Significant changes in the spectrum of microorganisms isolated from blood culture have been reported in cancer patients over the past years. The aim of our systematic review was to inventory the recent trends in epidemiology and antibiotic resistance of microorganisms causing bacteremia in cancer patients. Data for this review was identified by searches of Medline, Scopus and Cochrane Library for indexed articles and abstracts published in English since 2008. The principal search terms were: "antimicrobial resistance", "bacteremia", "bacterial epidemiology", "bloodstream infection", "cancer patients", "carbapenem resistance", "Escherichia coli resistance", "extended-spectrum β-lactamase producing E. coli", "febrile neutropenia", "fluoroquinolone resistance", "neutropenic cancer patient", "vancomycin-resistant Enterococcus", and "multidrug resistance". Boolean operators (NOT, AND, OR) were also used in succession to narrow and widen the search. Altogether, 27 articles were selected to be analyzed in the review. We found that Gram-negative bacteria were the most frequent pathogen isolated, particularly in studies with minimal use of antibiotic prophylaxis. Another important trend is the extensive emergence of antimicrobial-resistant strains associated with increased risk of morbidity, mortality and cost. This increasing incidence of antibiotic resistance has been reported in Gram-negative bacteria as well as in Gram-positive bacteria. This exhaustive review, reporting the recent findings in epidemiology and antibiotic resistance of bacteremia in cancer patients, highlights the necessity of local continuous surveillance of bacteremia and stringent enforcement of antibiotic stewardship programs in cancer patients.

  14. Assessment of antibiotic resistance of Escherichia coli isolates and screening of Salmonella spp. in wild ungulates from Portugal.

    Science.gov (United States)

    Dias, Diana; Torres, Rita T; Kronvall, Göran; Fonseca, Carlos; Mendo, Sónia; Caetano, Tânia

    2015-09-01

    Antibiotic resistance is an emerging global problem. Wild animals are rarely exposed to antibiotics and therefore low levels of antibiotic resistance are expected. However, the growing interactions of these animals with humans and livestock may have a huge impact on their bacterial flora. This study aimed to assess the levels of antibiotic resistance in Escherichia coli isolated from widespread wild ungulates in Portugal. The interpretation of inhibition zone diameters was performed according to clinical breakpoints and epidemiological cut-offs, determined with the normalized resistance interpretation (NRI) method. For clinical breakpoints, 16% of the isolates were resistant to at least one antibiotic, including ampicillin (10%), tetracycline (9%), streptomycin (5%) co-trimoxazole (4%), amoxicillin/clavulanic acid (1%) and cefoxitin (1%). The levels of resistance detected in E. coli strains isolated from wild boar were statistically different for ampicillin and co-trimoxasol. According to NRI cut-offs, 10% of the population showed a non-wild-type phenotype against at least one antibiotic, also including tetracycline (9%), co-trimoxazole (6%), streptomycin (4%), ampicillin (2%) and amoxicillin/clavulanic acid (1%). Considering this parameter of comparison, no statistically different levels of resistance were identified between E. coli recovered from the three wild ungulates. Screening of Salmonella spp., which can be potentially pathogenic, was also performed, revealing that its prevalence was very low (1.5%). The study demonstrated that wild ungulates from Portugal are also reservoirs of antibiotic-resistant bacteria.

  15. 3种典型消毒副产物对细菌抗生素抗性的影响%Effect of Three Typical Disinfection Byproducts on Bacterial Antibiotic Resistance

    Institute of Scientific and Technical Information of China (English)

    吕露; 张梦露; 王春明; 林惠荣; 于鑫

    2015-01-01

    本文研究了消毒副产物对细菌抗生素抗性的作用.分别选取三卤甲烷类(THMs)﹑卤乙酸类(HAAs)以及醛类消毒副产物中典型物质一氯二溴甲烷(CDBM)﹑碘乙酸(IAA)和水合三氯乙醛(CH),研究了细菌经消毒副产物染毒之后,对多种抗生素的抗性变化情况.结果发现,3种消毒副产物均可以诱导野生型铜绿假单胞菌提高对5种受试抗生素的抗性,提高作用IAA 〉 CH 〉 CDBM. IAA 对多重抗性也具有一定的提高作用.野生型大肠杆菌的抗生素抗性同样能够被 DBPs 诱导提高,说明DBPs 对抗性的影响具有普遍性.其作用机制可能是 DBPs 通过氧化胁迫机制诱导细菌发生突变,进而提高细菌抗生素抗性.本研究表明饮用水系统中部分细菌抗生素抗性的获得可能与消毒副产物有关;除毒理学风险外,消毒副产物的流行病学风险同样不容忽视.%The effect of typical disinfection byproducts ( DBPs) on bacterial antibiotic resistance was investigated in this study. chlorodibromomethane (CDBM), iodoacetic acid (IAA) and chloral hydrate (CH) were selected, which belong to trihalomethanes (THMs), haloacetic acids (HAAs) and aldehydes, respectively. After exposure to the selected DBPs, the resistance change of the tested strains to antibiotics was determined. As a result, all of the three DBPs induced Pseudomonas aeruginosa PAO1 to gain increased resistance to the five antibiotics tested, and the DBPs ranked as IAA 〉 CH 〉 CDBM according to their enhancement effects. Multidrug resistance could also be enhanced by treatment with IAA. The same result was observed in Escherichia coli K12, suggesting that the effect of DBPs on antibiotic resistance was a common phenomenon. The mechanism was probably that DBPs stimulated oxidative stress, which induced mutagenesis. And the antibiotic resistance mutation frequency could be increased along with mutagenesis. This study revealed that the acquisition of bacterial

  16. Antibiotic resistance shaping multi-level population biology of bacteria.

    Science.gov (United States)

    Baquero, Fernando; Tedim, Ana P; Coque, Teresa M

    2013-01-01

    Antibiotics have natural functions, mostly involving cell-to-cell signaling networks. The anthropogenic production of antibiotics, and its release in the microbiosphere results in a disturbance of these networks, antibiotic resistance tending to preserve its integrity. The cost of such adaptation is the emergence and dissemination of antibiotic resistance genes, and of all genetic and cellular vehicles in which these genes are located. Selection of the combinations of the different evolutionary units (genes, integrons, transposons, plasmids, cells, communities and microbiomes, hosts) is highly asymmetrical. Each unit of selection is a self-interested entity, exploiting the higher hierarchical unit for its own benefit, but in doing so the higher hierarchical unit might acquire critical traits for its spread because of the exploitation of the lower hierarchical unit. This interactive trade-off shapes the population biology of antibiotic resistance, a composed-complex array of the independent "population biologies." Antibiotics modify the abundance and the interactive field of each of these units. Antibiotics increase the number and evolvability of "clinical" antibiotic resistance genes, but probably also many other genes with different primary functions but with a resistance phenotype present in the environmental resistome. Antibiotics influence the abundance, modularity, and spread of integrons, transposons, and plasmids, mostly acting on structures present before the antibiotic era. Antibiotics enrich particular bacterial lineages and clones and contribute to local clonalization processes. Antibiotics amplify particular genetic exchange communities sharing antibiotic resistance genes and platforms within microbiomes. In particular human or animal hosts, the microbiomic composition might facilitate the interactions between evolutionary units involved in antibiotic resistance. The understanding of antibiotic resistance implies expanding our knowledge on multi

  17. Regional characteristics of postoperative bacterial infection and antibiotic resistance following traumatic limb fractures%四肢创伤性骨折术后细菌感染及耐药的地域性特征分析

    Institute of Scientific and Technical Information of China (English)

    任有亮; 彭笳宸; 李政道; 刘曦明; 杨晋; Stephen L.Kates; Edward M.Schwarz; Chao Xie

    2016-01-01

    结果分析、对本地区感染病灶彻底清除术前后经验性抗生素治疗的选择建议为:Gram阳性细菌感染选用替加环素、呋喃妥因、万古霉素,Gram阴性细菌感染选用亚胺硫霉素为宜.%Objective To investigate regional characteristics of postoperative Gram-positive/negative bacterial infection and antibiotic resistance following traumatic limb fracture patients in Southwest of China,and to provide evidence-based guidelines for empiric antibiotic therapy.Methods All human subject studies were performed using protocols approved by the institutional review board.A retrospective chart review was performed of 3,728 medical records of the patients who had been treated for extremity traumatic fracture from January 2012 to January 2015.Included in the present study were 51 patients whose osteomyelitis had been confirmed by Gram-positive/negative bacterial infections,and susceptibility data determined by the M-100-S22 protocol (Clinical & Laboratory Standards Institute(CLSI) 2012 USA).The data of fracture type with Gram-positive/negative,MRSA(methicillin-resistant S.aureus)/MSSA (methicillin-susceptible S.aureus) distribution and antibiotic resistance were analyzed.Results The overall postoperative infection rate was 1.37% (51/3,728).In the 51 osteomyelitis patients:the most common fracture sites were tibia-fibula (25 cases,49.02%),femur (11 cases,21.57%) and radius-ulna(8 cases,15.69%).Monomicrobial infection was found in 45 cases of them (88.23%) and polymicrobial infection in 6(11.76%).The Gram-positive infections were caused by S.aureus (27 cases,47.37%),S.epidermidis (4 cases,7.02%) and Enterococcus avium (2 cases,3.51%) and the Gram-negative infections mainly by E.coli (9 cases,15.79%),E.cloacae (4 cases,7.02%),and Klebsiella pneumonia (2 cases,3.51%).The antibiotic resistance by the Gram-positive bacteria was observed in penicillin and erythromycin (100%),lincomycin (51.86% by S.aureus,75% by S

  18. Antibiotic resistance among Helicobacter pylori clinical isolates in Lima, Peru

    Science.gov (United States)

    Boehnke, Kevin F; Valdivieso, Manuel; Bussalleu, Alejandro; Sexton, Rachael; Thompson, Kathryn C; Osorio, Soledad; Reyes, Italo Novoa; Crowley, John J; Baker, Laurence H; Xi, Chuanwu

    2017-01-01

    Objectives Gastric carcinoma is the most common cancer and cause of cancer mortality in Peru. Helicobacter pylori, a bacterium that colonizes the human stomach, is a Group 1 carcinogen due to its causal relationship to gastric carcinoma. While eradication of H. pylori can help prevent gastric cancer, characterizing regional antibiotic resistance patterns is necessary to determine targeted treatment for each region. Thus, we examined primary antibiotic resistance in clinical isolates of H. pylori in Lima, Peru. Materials and methods H. pylori strains were isolated from gastric biopsies of patients with histologically proven H. pylori infection. Primary antibiotic resistance among isolates was examined using E-test strips. Isolates were examined for the presence of the cagA pathogenicity island and the vacA m1/m2 alleles via polymerase chain reaction. Results Seventy-six isolates were recovered from gastric biopsies. Clinical isolates showed evidence of antibiotic resistance to 1 (27.6%, n=21/76), 2 (28.9%, n=22/76), or ≥3 antibiotics (40.8%). Of 76 isolates, eight (10.5%) were resistant to amoxicillin and clarithromycin, which are part of the standard triple therapy for H. pylori infection. No trends were seen between the presence of cagA, vacA m1, or vacA m2 and antibiotic resistance. Conclusion The rate of antibiotic resistance among H. pylori isolates in Lima, Peru, is higher than expected and presents cause for concern. To develop more targeted eradication therapies for H. pylori in Peru, more research is needed to better characterize antibiotic resistance among a larger number of clinical isolates prospectively. PMID:28331349

  19. Crystallographic Studies of Two Bacterial AntibioticResistance Enzymes: Aminoglycoside Phosphotransferase (2')-Ic and GES-1\\beta-lactamase

    Energy Technology Data Exchange (ETDEWEB)

    Brynes, Laura; /Rensselaer Poly.

    2007-10-31

    Guiana Extended-Spectrum-1 (GES-1) and Aminoglycoside phosphotransferase (2')-Ic (APH(2')-Ic) are two bacteria-produced enzymes that essentially perform the same task: they provide resistance to an array of antibiotics. Both enzymes are part of a growing resistance problem in the medical world. In order to overcome the ever-growing arsenal of antibiotic-resistance enzymes, it is necessary to understand the molecular basis of their action. Accurate structures of these proteins have become an invaluable tool to do this. Using protein crystallography techniques and X-ray diffraction, the protein structure of GES-1 bound to imipenem (an inhibitor) has been solved. Also, APH(2')-Ic has been successfully crystallized, but its structure was unable to be solved using molecular replacement using APH(2')-Ib as a search model. The structure of GES-1, with bound imipenem was solved to a resolution of 1.89A, and though the inhibitor is bound with only moderate occupancy, the structure shows crucial interactions inside the active site that render the enzyme unable to complete the hydrolysis of the {beta}-lactam ring. The APH(2')-Ic dataset could not be matched to the model, APH(2')-Ib, with which it shares 25% sequence identity. The structural information gained from GES-1, and future studies using isomorphous replacement to solve the APH(2')-Ic structure can aid directly to the creation of novel drugs to combat both of these classes of resistance enzymes.

  20. Molecular tools for the characterisation of antibiotic-resistant bacteria

    NARCIS (Netherlands)

    Aarts, H.J.M.; Boumedine, K.S.; Nesme, X.; Cloeckaert, A.

    2001-01-01

    This review will discuss a number of molecular tools which are currently used as well as some innovative approaches for the characterisation of antibiotic-resistant bacterial strains. Various methods involved in the detection and characterisation of genes and mutations associated with antibiotic res

  1. Determination of the Antibiotic Resistance Profile of Student Cell Phones

    Directory of Open Access Journals (Sweden)

    Lisa Ann Blankinship

    2012-08-01

    Full Text Available Sampling of common use items (e.g., student cell phones for bacterial presence, identification, and antibiotic resistance profiling helps students to recognize the need for routine cleaning of personal items and encourages thoughtful use of currently available medications. This multilab period project can be used to teach or reinforce several methods from general microbiology including aseptic technique, isolation streak, serial dilution, spread plating, Kirby Bauer testing, unknown identification, and media production. The data generated can be saved and added to each semester, thus providing a data set that reflects a local trend of antibiotic resistance.      

  2. Mechanisms of Helicobacter pylori antibiotic resistance and molecular testing

    Directory of Open Access Journals (Sweden)

    Toshihiro eNishizawa

    2014-10-01

    Full Text Available Antibiotic resistance in Helicobacter pylori (H. pylori is the main factor affecting the efficacy of current treatment methods against infection caused by this organism. The traditional culture methods for testing bacterial susceptibility to antibiotics are expensive and require 10 to 14 days. Since resistance to clarithromycin, fluoroquinolone, and tetracycline seems to be exclusively caused by specific mutations in a small region of the responsible gene, molecular methods offer an attractive alternative to the above-mentioned techniques. The technique of polymerase chain reaction (PCR is an accurate and rapid method for the detection of mutations that confer antibiotic resistance. This review highlights the mechanisms of antibiotic resistance in H. pylori and the molecular methods for antibiotic susceptibility testing.

  3. Antibiotic Resistant Salmonella and Vibrio Associated with Farmed Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Sanjoy Banerjee

    2012-01-01

    Full Text Available Salmonella and Vibrio species were isolated and identified from Litopenaeus vannamei cultured in shrimp farms. Shrimp samples showed occurrence of 3.3% of Salmonella and 48.3% of Vibrio. The isolates were also screened for antibiotic resistance to oxolinic acid, sulphonamides, tetracycline, sulfamethoxazole/trimethoprim, norfloxacin, ampicillin, doxycycline hydrochloride, erythromycin, chloramphenicol, and nitrofurantoin. Salmonella enterica serovar Corvallis isolated from shrimp showed individual and multiple antibiotic resistance patterns. Five Vibrio species having individual and multiple antibiotic resistance were also identified. They were Vibrio cholerae (18.3%, V. mimicus (16.7%, V. parahaemolyticus (10%, V. vulnificus (6.7%, and V. alginolyticus (1.7%. Farm owners should be concerned about the presence of these pathogenic bacteria which also contributes to human health risk and should adopt best management practices for responsible aquaculture to ensure the quality of shrimp.

  4. Antibiotic resistant Salmonella and Vibrio associated with farmed Litopenaeus vannamei.

    Science.gov (United States)

    Banerjee, Sanjoy; Ooi, Mei Chen; Shariff, Mohamed; Khatoon, Helena

    2012-01-01

    Salmonella and Vibrio species were isolated and identified from Litopenaeus vannamei cultured in shrimp farms. Shrimp samples showed occurrence of 3.3% of Salmonella and 48.3% of Vibrio. The isolates were also screened for antibiotic resistance to oxolinic acid, sulphonamides, tetracycline, sulfamethoxazole/trimethoprim, norfloxacin, ampicillin, doxycycline hydrochloride, erythromycin, chloramphenicol, and nitrofurantoin. Salmonella enterica serovar Corvallis isolated from shrimp showed individual and multiple antibiotic resistance patterns. Five Vibrio species having individual and multiple antibiotic resistance were also identified. They were Vibrio cholerae (18.3%), V. mimicus (16.7%), V. parahaemolyticus (10%), V. vulnificus (6.7%), and V. alginolyticus (1.7%). Farm owners should be concerned about the presence of these pathogenic bacteria which also contributes to human health risk and should adopt best management practices for responsible aquaculture to ensure the quality of shrimp.

  5. The genomic enzymology of antibiotic resistance.

    Science.gov (United States)

    Morar, Mariya; Wright, Gerard D

    2010-01-01

    The need for new antibiotic therapies is acute and growing in large part because of the emergence of drug-resistant pathogens. A vast number of resistance determinants are, however, found in nonpathogenic micro-organisms. The resistance totality in the global microbiota is the antibiotic resistome and includes not only established resistance genes but also genes that have the potential to evolve into resistance elements. We term these proto-resistance genes and hypothesize that they share common ancestry with other functional units known as housekeeping genes. Genomic enzymology is the study of protein structure-function in light of genetic context and evolution of protein superfamilies. This concept is highly applicable to study of antibiotic resistance evolution from proto-resistance elements. In this review, we summarize some of the genomic enzymology evidence for resistance enzymes pointing to common ancestry with genes of other metabolic functions. Genomic enzymology plays a key role in understanding the origins of antibiotic resistance and aids in designing strategies for diagnosis and prevention thereof.

  6. Gene Network Analysis of Metallo Beta Lactamase Family Proteins Indicates the Role of Gene Partners in Antibiotic Resistance and Reveals Important Drug Targets.

    Science.gov (United States)

    Parimelzaghan, Anitha; Anbarasu, Anand; Ramaiah, Sudha

    2016-06-01

    Metallo Beta (β) Lactamases (MBL) are metal dependent bacterial enzymes that hydrolyze the β-lactam antibiotics. In recent years, MBL have received considerable attention because it inactivates most of the β-lactam antibiotics. Increase in dissemination of MBL encoding antibiotic resistance genes in pathogenic bacteria often results in unsuccessful treatments. Gene interaction network of MBL provides a complete understanding on the molecular basis of MBL mediated antibiotic resistance. In our present study, we have constructed the MBL network of 37 proteins with 751 functional partners from pathogenic bacterial spp. We found 12 highly interconnecting clusters. Among the 37 MBL proteins considered in the present study, 22 MBL proteins are from B3 subclass, 14 are from B1 subclass and only one is from B2 subclass. Global topological parameters are used to calculate and compare the probability of interactions in MBL proteins. Our results indicate that the proteins associated within the network have a strong influence in antibiotic resistance mechanism. Interestingly, several drug targets are identified from the constructed network. We believe that our results would be helpful for researchers exploring MBL-mediated antibiotic resistant mechanisms.

  7. Use of Bacteriophages to control bacterial pathogens

    Science.gov (United States)

    Lytic bacteriophages can provide a natural method and an effective alternative to antibiotics to reduce bacterial pathogens in animals, foods, and other environments. Bacteriophages (phages) are viruses which infect bacterial cells and eventually kill them through lysis, and represent the most abun...

  8. Proteomics of Foodborne Bacterial Pathogens

    Science.gov (United States)

    Fagerquist, Clifton K.

    This chapter is intended to be a relatively brief overview of proteomic techniques currently in use for the identification and analysis of microorganisms with a special emphasis on foodborne pathogens. The chapter is organized as follows. First, proteomic techniques are introduced and discussed. Second, proteomic applications are presented specifically as they relate to the identification and qualitative/quantitative analysis of foodborne pathogens.

  9. The effect of broiler litter, swine effluent, and municipal biosolids land application on small plot pathogen, antibiotic resistance, and nutrient levels

    Science.gov (United States)

    Land applying agricultural and municipal wastes carries an inherent risk associated with nutrient and pathogen runoff and contamination, but with that risk comes a potentially sustainable process to reclaim otherwise residual waste material. Few studies compare the two residuals. The purpose of th...

  10. Prevalence, pathogenic capability, virulence genes, biofilm formation, and antibiotic resistance of Listeria in goat and sheep milk confirms need of hygienic milking conditions.

    Science.gov (United States)

    Osman, Kamelia M; Zolnikov, Tara Rava; Samir, Ahmed; Orabi, Ahmed

    2014-01-01

    Goat and sheep milk is consumed by human populations throughout the world; as a result, it has been proposed as an alternative, nutrient-rich milk to feed infants allergic to cow's milk. Unfortunately, potentially harmful bacteria have not been thoroughly tested in goat or sheep milk. Listeria monocytogenes is a harmful bacterium that causes adverse health effects if ingested by humans. The purpose of this study was to estimate the prevalence and characterize the phenotype, genotype, virulence factors, biofilm formation, and antibiopotential of Listeria isolated from the milk of goat and sheep. Udder milk samples were collected from 107 goats and 102 sheep and screened for mastitis using the California mastitis test (CMT). Samples were then examined for the presence of pathogenic Listeria spp; if detected, the isolation of pathogenic Listeria (L. monocytogenes and Listeria ivanovii) was completed using isolation and identification techniques recommended by the International Organization for Standards (ISO 11290-1, 1996), in addition to serological, in vitro and in vivo pathogenicity tests. The isolates were subjected to PCR assay for virulence associated genes (hlyA, plcA, actA, and iap). Pathogenic Listeria spp. were isolated from 5·6% of goat and 3·9% sheep milk samples, with 33·3 and 25% of these selected samples respectively containing L. monocytogenes. The results of this study provide evidence of the low-likelihood of contamination leading to the presence of L. monocytogenes in raw goat and sheep milk; however, this study also confirmed a strong in vitro ability for biofilm formation and pathogenic capability of L. monocytogenes if discovered in the milk. L. monocytogenes may be present in goat and sheep milk and in order to reduce the exposure, hygienic milking conditions must be employed for the milk to be considered a safe alternative for human consumption.

  11. REDUCTION OF ANTIBIOTIC RESISTANCE IN BACTERIA: A REVIEW

    OpenAIRE

    Suresh Jaiswal et al.

    2012-01-01

    Drug resistant bacteria have been posing a major challenge to the effective control of bacterial infections for quite some time. One of the main causes of antibiotics drug resistance is antibiotic overuse, abuse, and in some cases, misuse, due to incorrect diagnosis. Bacterial antibiotic resistance is a significant issues faced by various industries, including the food and agricultural industries, the medical and veterinary profession and others. The potential for transfer of antibiotics resi...

  12. Antibiotic resistance in cancer patients.

    Science.gov (United States)

    Gudiol, Carlota; Carratalà, Jordi

    2014-08-01

    Bacterial infection is one of the most frequent complications in cancer patients and hematopoietic stem cell transplant recipients. In recent years, the emergence of antimicrobial resistance has become a significant problem worldwide, and cancer patients are among those affected. Treatment of infections due to multidrug-resistant (MDR) bacteria represents a clinical challenge, especially in the case of Gram-negative bacilli, since the therapeutic options are often very limited. As the antibiotics active against MDR bacteria present several disadvantages (limited clinical experience, higher incidence of adverse effects, and less knowledge of the pharmacokinetics of the drug), a thorough acquaintance with the main characteristics of these drugs is mandatory in order to provide safe treatment to cancer patients with MDR bacterial infections. Nevertheless, the implementation of antibiotic stewardship programs and infection control measures is the cornerstone for controlling the development and spread of these MDR pathogens.

  13. Prevalence of MDR pathogens of bacterial meningitis in Egypt and new synergistic antibiotic combinations

    Science.gov (United States)

    Abdelkader, Mona M.; Aboshanab, Khaled M.; El-Ashry, Marwa A.; Aboulwafa, Mohammad M.

    2017-01-01

    The aim of this study was identifying bacterial pathogens involved in meningitis, studying their antibiotic resistance profiles, investigating the antibiotic resistance genes as well as evaluating the use of various antibiotic combinations. Antibiotic susceptibility tests were evaluated according to CLSI guidelines. Antibiotic combinations were evaluated by calculating the Fractional Inhibitory Concentration (FIC) index. A total of 71 bacterial isolates were recovered from 68 culture positive CSF specimens. Sixty five of these isolates (91.5%) were recovered from single infection specimens, while 6 isolates (8.4%) were recovered from mixed infection specimens. Out of the 71 recovered isolates, 48 (67.6%) were Gram-positive, and 23 (32.4%) were Gram-negative. Thirty one of the Gram positive isolates were S. pneumoniae (64.6%, n = 48). Out of the recovered 71 isolates; 26 (36.6%) were multidrug-resistant (MDR) isolates of which, 18 (69.2%) were Gram-negative and 8 (30.8%) were Gram-positive. All MDR isolates (100%) showed resistance to penicillin and ampicillin, however, they showed lower resistance to meropenem (50%), levofloxacin (50%), amikacin (48%), pipercillin-tazobactam (45.8%). Most common antibiotic resistance genes were investigated including: tem (21.1%), shv (15.8%), ctx-m (15.8%) coding for TEM-, SHV, CTX-M extended-spectrum beta-lactamases (ESBLs), respectively; aac(6')-I b(26.3%) coding for aminoglycoside 6’-N-acetyltransferase type Ib ciprofloxacin resistant variant; and qnrA (5.3%) gene coding for quinolone resistance. The DNA sequences of the respective resistance genes of some selected isolates were PCR amplified, analyzed and submitted to the GenBank database under the accession numbers, KX214665, KX214664, KX214663, KX214662, respectively. The FIC values for ampicillin/sulbactam plus cefepime showed either additive or synergistic effect against ten tested Gram-negative MDR isolates, while doxycycline plus levofloxacin combination revealed

  14. Development of Quorum-Based Anti-Virulence Therapeutics Targeting Gram-Negative Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Wen Shan Yew

    2013-08-01

    Full Text Available Quorum sensing is a cell density-dependent signaling phenomenon used by bacteria for coordination of population-wide phenotypes, such as expression of virulence genes, antibiotic resistance and biofilm formation. Lately, disruption of bacterial communication has emerged as an anti-virulence strategy with enormous therapeutic potential given the increasing incidences of drug resistance in pathogenic bacteria. The quorum quenching therapeutic approach promises a lower risk of resistance development, since interference with virulence generally does not affect the growth and fitness of the bacteria and, hence, does not exert an associated selection pressure for drug-resistant strains. With better understanding of bacterial communication networks and mechanisms, many quorum quenching methods have been developed against various clinically significant bacterial pathogens. In particular, Gram-negative bacteria are an important group of pathogens, because, collectively, they are responsible for the majority of hospital-acquired infections. Here, we discuss the current understanding of existing quorum sensing mechanisms and present important inhibitory strategies that have been developed against this group of pathogenic bacteria.

  15. Antibiotic Resistant Bacteria And Their Associated Resistance Genes in a Conventional Municipal Wastewater Treatment Plant

    KAUST Repository

    Aljassim, Nada I.

    2013-12-01

    With water scarcity as a pressing issue in Saudi Arabia and other Middle Eastern countries, the treatment and reuse of municipal wastewater is increasingly being used as an alternative water source to supplement country water needs. Standards are in place to ensure a safe treated wastewater quality, however they do not regulate pathogenic bacteria and emerging contaminants. Information is lacking on the levels of risk to public health associated with these factors, the efficiency of conventional treatment strategies in removing them, and on wastewater treatment in Saudi Arabia in general. In this study, a municipal wastewater treatment plant in Saudi Arabia is investigated to assess the efficiency of conventional treatment in meeting regulations and removing pathogens and emerging contaminants. The study found pathogenic bacterial genera, antibiotic resistance genes and antibiotic resistant bacteria, many of which were multi-resistant in plant discharges. It was found that although the treatments are able to meet traditional quality guidelines, there remains a risk from the discussed contaminants with wastewater reuse. A deeper understanding of this risk, and suggestions for more thorough guidelines and monitoring are needed.

  16. Bioinformatics and structural characterization of a hypothetical protein from Streptococcus mutans: implication of antibiotic resistance.

    Directory of Open Access Journals (Sweden)

    Jie Nan

    Full Text Available As an oral bacterial pathogen, Streptococcus mutans has been known as the aetiologic agent of human dental caries. Among a total of 1960 identified proteins within the genome of this organism, there are about 500 without any known functions. One of these proteins, SMU.440, has very few homologs in the current protein databases and it does not fall into any protein functional families. Phylogenetic studies showed that SMU.440 is related to a particular ecological niche and conserved specifically in some oral pathogens, due to lateral gene transfer. The co-occurrence of a MarR protein within the same operon among these oral pathogens suggests that SMU.440 may be associated with antibiotic resistance. The structure determination of SMU.440 revealed that it shares the same fold and a similar pocket as polyketide cyclases, which indicated that it is very likely to bind some polyketide-like molecules. From the interlinking structural and bioinformatics studies, we have concluded that SMU.440 could be involved in polyketide-like antibiotic resistance, providing a better understanding of this hypothetical protein. Besides, the combination of multiple methods in this study can be used as a general approach for functional studies of a protein with unknown function.

  17. Microfluidic system for the identification of bacterial pathogens causing urinary tract infections

    Science.gov (United States)

    Becker, Holger; Hlawatsch, Nadine; Haraldsson, Tommy; van der Wijngaart, Wouter; Lind, Anders; Malhotra-Kumar, Surbi; Turlej-Rogacka, Agata; Goossens, Herman

    2015-03-01

    Urinary tract infections (UTIs) are among the most common bacterial infections and pose a significant healthcare burden. The growing trend in antibiotic resistance makes it mandatory to develop diagnostic kits which allow not only the determination of a pathogen but also the antibiotic resistances. We have developed a microfluidic cartridge which takes a direct urine sample, extracts the DNA, performs an amplification using batch-PCR and flows the sample over a microarray which is printed into a microchannel for fluorescence detection. The cartridge is injection-molded out of COP and contains a set of two-component injection-molded rotary valves to switch between input and to isolate the PCR chamber during thermocycling. The hybridization probes were spotted directly onto a functionalized section of the outlet microchannel. We have been able to successfully perform PCR of E.coli in urine in this chip and perform a fluorescence detection of PCR products. An upgraded design of the cartridge contains the buffers and reagents in blisters stored on the chip.

  18. Photoinactivation of major bacterial pathogens in aquaculture

    Directory of Open Access Journals (Sweden)

    Heyong Jin Roh

    2016-08-01

    Full Text Available Abstract Background Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and 68.4 J cm−2, respectively, produced one log reduction in the bacterial populations, whereas Streptococcus parauberis was the least susceptible (153.8 J cm−2 per one log reduction. In general, optical density (OD values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

  19. Acquired antibiotic resistance genes: an overview.

    OpenAIRE

    Hoek, Angela H.A.M. van; Dik eMevius; Beatriz eGuerra; Peter eMullany; Adam Paul Roberts; Aarts, Henk J. M.

    2011-01-01

    In this review an overview is given on antibiotic resistance mechanisms with special attentions to the antibiotic resistance genes described so far preceded by a short introduction on the discovery and mode of action of the different classes of antibiotics. As this review is only dealing with acquired resistance, attention is paid to mobile genetic elements such as plasmids, transposons and integrons, which are associated with antibiotic resistance genes, and involved in the dispersal of anti...

  20. Priorities for antibiotic resistance surveillance in Europe

    DEFF Research Database (Denmark)

    Fluit, A. C.; van der Bruggen, J. T.; Aarestrup, Frank Møller

    2006-01-01

    Antibiotic resistance is an increasing global problem. Surveillance studies are needed to monitor resistance development, to guide local empirical therapy, and to implement timely and adequate countermeasures. To achieve this, surveillance studies must have standardised methodologies...... to the various reservoirs of antibiotic-resistant bacteria, such as hospitalised patients, nursing homes, the community, animals and food. Two studies that could serve as examples of tailored programmes are the European Antimicrobial Resistance Surveillance System (EARSS), which collects resistance data during...... of antibiotic resistance....

  1. Antibiotic-resistant soil bacteria in transgenic plant fields.

    Science.gov (United States)

    Demanèche, Sandrine; Sanguin, Hervé; Poté, John; Navarro, Elisabeth; Bernillon, Dominique; Mavingui, Patrick; Wildi, Walter; Vogel, Timothy M; Simonet, Pascal

    2008-03-11

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 10-successive-year culture of the transgenic Bt176 corn, which has a blaTEM marker gene, could have had on the soil bacterial community. The bla gene encoding resistance to ampicillin belongs to the beta-lactam antibiotic family, which is widely used in medicine but is readily compromised by bacterial antibiotic resistance. Our results indicate that soil bacteria are naturally resistant to a broad spectrum of beta-lactam antibiotics, including the third cephalosporin generation, which has a slightly stronger discriminating effect on soil isolates than other cephalosporins. These high resistance levels for a wide range of antibiotics are partly due to the polymorphism of bla genes, which occur frequently among soil bacteria. The blaTEM116 gene of the transgenic corn Bt176 investigated here is among those frequently found, thus reducing any risk of introducing a new bacterial resistance trait from the transgenic material. In addition, no significant differences were observed in bacterial antibiotic-resistance levels between transgenic and nontransgenic corn fields, although the bacterial populations were different.

  2. Transfer of antibiotic-resistance genes via phage-related mobile elements.

    Science.gov (United States)

    Brown-Jaque, Maryury; Calero-Cáceres, William; Muniesa, Maite

    2015-05-01

    Antibiotic resistance is a major concern for society because it threatens the effective prevention of infectious diseases. While some bacterial strains display intrinsic resistance, others achieve antibiotic resistance by mutation, by the recombination of foreign DNA into the chromosome or by horizontal gene acquisition. In many cases, these three mechanisms operate together. Several mobile genetic elements (MGEs) have been reported to mobilize different types of resistance genes and despite sharing common features, they are often considered and studied separately. Bacteriophages and phage-related particles have recently been highlighted as MGEs that transfer antibiotic resistance. This review focuses on phages, phage-related elements and on composite MGEs (phages-MGEs) involved in antibiotic resistance mobility. We review common features of these elements, rather than differences, and provide a broad overview of the antibiotic resistance transfer mechanisms observed in nature, which is a necessary first step to controlling them.

  3. Plasmid metagenomics reveals multiple antibiotic resistance gene classes among the gut microbiomes of hospitalised patients

    DEFF Research Database (Denmark)

    Jitwasinkul, Tossawan; Suriyaphol, Prapat; Tangphatsornruang, Sithichoke

    2016-01-01

    Antibiotic resistance genes are rapidly spread between pathogens and the normal flora, with plasmids playing an important role in their circulation. This study aimed to investigate antibiotic resistance plasmids in the gut microbiome of hospitalised patients. Stool samples were collected from seven...... sequences (using >80% alignment length as the cut-off), and ResFinder was used to classify the antibiotic resistance gene pools. Plasmid replicon modules were used for plasmid typing. Forty-six genes conferring resistance to several classes of antibiotics were identified in the stool samples. Several...... antibiotic resistance genes were shared by the patients; interestingly, most were reported previously in food animals and healthy humans. Four antibiotic resistance genes were found in the healthy subject. One gene (aph3-III) was identified in the patients and the healthy subject and was related...

  4. Molecular Mechanisms of Bacterial Pathogenicity

    Science.gov (United States)

    Fuchs, Thilo Martin

    Cautious optimism has arisen over recent decades with respect to the long struggle against bacteria, viruses, and parasites. This has been offset, however, by a fatal complacency stemming from previous successes such as the development of antimicrobial drugs, the eradication of smallpox, and global immunization programs. Infectious diseases nevertheless remain the world's leading cause of death, killing at least 17 million persons annually [61]. Diarrheal diseases caused by Vibrio cholerae or Shigella dysenteriae kill about 3 million persons every year, most of them young children: Another 4 million die of tuberculosis or tetanus. Outbreaks of diphtheria in Eastern Europe threatens the population with a disease that had previously seemed to be overcome. Efforts to control infectious diseases more comprehensively are undermined not only by socioeconomic conditions but also by the nature of the pathogenic organisms itself; some isolates of Staphylococcus aureus and Enterobacter have become so resistant to drugs by horizontal gene transfer that they are almost untreatable. In addition, the mechanism of genetic variability helps pathogens to evade the human immune system, thus compromising the development of powerful vaccines. Therefore detailed knowledge of the molecular mechanisms of microbial pathogenicity is absolutely necessary to develop new strategies against infectious diseases and thus to lower their impact on human health and social development.

  5. Analysis of Distribution and Antibiotic Resistance of Pathogenic Bacteria of Blood Cultures in Newborns in Nanjing Area%南京地区新生儿血培养病原菌分布及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    张晓洁; 邱胜丰; 葛高霞; 黎青

    2012-01-01

    目的:了解南京地区新生儿败血症病原菌分布及其耐药情况,为临床合理选择抗生素提供参考.方法:收集2009年1月-2011年9月我院住院新生儿血培养标本1546例,分析其病原菌分布及耐药性.结果:1 546例新生儿血培养标本共检出细菌186株,总阳性率为12.03%,因无临床表现支持而被视为假菌血症者7例,污染率为3.76%(7/186).其中革兰阳性茵129株,占总分离菌的72.07%,革兰阳性菌以凝固酶阴性葡萄球菌为主,占革兰阳性茵的76.74%,占总分离菌的55.31%;革兰阴性菌50株,占总分离菌的27.93%,革兰阴性菌以肺炎克雷伯茵居多,占革兰阴性菌的42.00%,占总分离菌的11.73%.革兰阳性菌对抗生素耐药率最高的为青霉素,其次为红霉素,对万古霉素、哌拉西林/他唑巴坦、阿米卡星以及左氧氟沙星表现了较低的耐药率;革兰阴性菌对抗生素耐药率最高的为氨苄西林,其次为哌拉西林、头孢唑林、氨曲南,对亚胺培南、头孢吡肟、阿米卡星、左氧氟沙星以及加酶抑制剂的复合制剂表现了较低的耐药率.结论:凝固酶阴性葡萄球菌是南京地区近2年新生儿败血症最常见的病原菌,其次为肺炎克雷伯菌,对常用抗生素均有不同程度的耐药.%OBJECTIVE: To investigate distribution and antibiotic resistance of pathogens causing neonatal septicemia and to provide evidence for reasonable use of antibiotics in clinic in Nanjing area. METHODS: 1546 neonatal blood samples were collect-ed from our hospital during Jan. 2009 -Sept. 2011. The distribution and antibiotic resistance of pathogens causing neonatal septice-mia were analyzed. RESULTS: 186 pathogenic strains were isolated from 1546 specimens and the positive rate was 12.03%. 7 cas-es were considered as false bacteremia due to non-clinical support, in which contamination rate was 3.76% (7/186). Among them, 129 strains were Gram-positive bacteria (72.07% ) , and the

  6. Recent Insights into Antibiotic Resistance in Helicobacter pylori Eradication

    Directory of Open Access Journals (Sweden)

    Wenming Wu

    2012-01-01

    Full Text Available Antibiotics have been useful in the treatment of H. pylori-related benign and malignant gastroduodenal diseases. However, emergence of antibiotic resistance often decreases the eradication rates of H. pylori infections. Many factors have been implicated as causes of treatment failure, but the main antibiotic resistance mechanisms described to date are due to point mutations on the bacterial chromosome, a consequence of a significantly phenotypic variation in H. pylori. The prevalence of antibiotic (e.g., clarithromycin, metronidazole, tetracycline, amoxicillin, and furazolidone resistance varies among different countries; it appears to be partly determined by geographical factors. Since the worldwide increase in the rate of antibiotic resistance represents a problem of relevance, some studies have been performed in order to identify highly active and well-tolerated anti-H. pylori therapies including sequential, concomitant quadruple, hybrid, and quadruple therapy. These represent a promising alternatives in the effort to overcome the problem of resistance. The aim of this paper is to review the current status of antibiotic resistance in H. pylori eradication, highlighting the evolutionary processes in detail at alternative approaches to treatment in the past decade. The underlying resistance mechanisms will be also followed.

  7. Occurrence and prevalence of antibiotic resistance in landfill leachate.

    Science.gov (United States)

    Wang, Yangqing; Tang, Wei; Qiao, Jing; Song, Liyan

    2015-08-01

    Antibiotic resistance (AR) is extensively present in various environments, posing emerging threat to public and environmental health. Landfill receives unused and unwanted antibiotics through household waste and AR within waste (e.g., activated sludge and illegal clinical waste) and is supposed to serve as an important AR reservoir. In this study, we used culture-dependent methods and quantitative molecular techniques to detect and quantify antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in 12 landfill leachate samples from six geographic different landfills, China. Five tested ARGs (tetO, tetW, bla(TEM), sulI, and sulII) and seven kinds of antibiotic-resistant heterotrophic ARB were extensively detected in all samples, demonstrating their occurrence in landfill. The detected high ratio (10(-2) to 10(-5)) of ARGs to 16S ribosomal RNA (rRNA) gene copies implied that ARGs are prevalent in landfill. Correlation analysis showed that ARGs (tetO, tetW, sulI, and sulII) significantly correlated to ambient bacterial 16S rRNA gene copies, suggesting that the abundance of bacteria in landfill leachate may play an important role in the horizontal spread of ARGs.

  8. Detecção da resistência a antibióticos de bactérias isoladas de casos clínicos ocorridos em animais de companhia Detection of antibiotic resistance in clinical bacterial strains from pets

    Directory of Open Access Journals (Sweden)

    P. Poeta

    2008-04-01

    Full Text Available The identification of different bacterial strains and the occurrence of antibiotic resistance were investigated in several infection processes of pets as skin abscess with purulent discharge, bronco alveolar fluid, earwax, urine, mammary, and eye fluid. Streptococcus spp. and Staphylococcus spp. were the most detected in the different samples. A high frequency of antimicrobial resistance has been observed and this could reflect the wide use of antimicrobials in pets, making the effectiveness of antibiotic treatment to become more complicated.

  9. Antibiotic resistance mechanisms inform discovery: identification and characterization of a novel amycolatopsis strain producing ristocetin.

    Science.gov (United States)

    Truman, Andrew W; Kwun, Min Jung; Cheng, Jinhua; Yang, Seung Hwan; Suh, Joo-Won; Hong, Hee-Jeon

    2014-10-01

    Discovering new antibiotics is a major scientific challenge, made increasingly urgent by the continued development of resistance in bacterial pathogens. A fundamental understanding of the mechanisms of bacterial antibiotic resistance will be vital for the future discovery or design of new, more effective antibiotics. We have exploited our intimate knowledge of the molecular mechanism of glycopeptide antibiotic resistance in the harmless bacterium Streptomyces coelicolor to develop a new two-step cell wall bioactivity screen, which efficiently identified a new actinomycete strain containing a previously uncharacterized glycopeptide biosynthetic gene cluster. The screen first identifies natural product extracts capable of triggering a generalized cell wall stress response and then specifically selects for glycopeptide antibacterials by assaying for the induction of glycopeptide resistance genes. In this study, we established a diverse natural product extract library from actinomycete strains isolated from locations with widely varying climates and ecologies, and we screened them using the novel two-step bioassay system. The bioassay ultimately identified a single strain harboring the previously unidentified biosynthetic gene cluster for the glycopeptide ristocetin, providing a proof of principle for the effectiveness of the screen. This is the first report of the ristocetin biosynthetic gene cluster, which is predicted to include some interesting and previously uncharacterized enzymes. By focusing on screening libraries of microbial extracts, this strategy provides the certainty that identified producer strains are competent for growth and biosynthesis of the detected glycopeptide under laboratory conditions.

  10. Antibiotic resistance: An ethical challenge.

    Science.gov (United States)

    Littmann, Jasper; Buyx, Alena; Cars, Otto

    2015-10-01

    In this paper, we argue that antibiotic resistance (ABR) raises a number of ethical problems that have not yet been sufficiently addressed. We outline four areas in which ethical issues that arise in relation to ABR are particularly pressing. First, the emergence of multidrug-resistant and extensively drug-resistant infections exacerbates traditional ethical challenges of infectious disease control, such as the restriction of individual liberty for the protection of the public's health. Second, ABR raises issues of global distributive justice, both with regard to the overuse and lack of access to antibiotics. Third, the use of antibiotics in veterinary medicine raises serious concerns for animal welfare and sustainable farming practices. Finally, the diminishing effectiveness of antibiotics leads to questions about intergenerational justice and our responsibility for the wellbeing of future generations. We suggest that current policy discussions should take ethical conflicts into account and engage openly with the challenges that we outline in this paper.

  11. Antibiotic resistance determinants in a Pseudomonas putida strain isolated from a hospital.

    Directory of Open Access Journals (Sweden)

    Lázaro Molina

    Full Text Available Environmental microbes harbor an enormous pool of antibiotic and biocide resistance genes that can impact the resistance profiles of animal and human pathogens via horizontal gene transfer. Pseudomonas putida strains are ubiquitous in soil and water but have been seldom isolated from humans. We have established a collection of P. putida strains isolated from in-patients in different hospitals in France. One of the isolated strains (HB3267 kills insects and is resistant to the majority of the antibiotics used in laboratories and hospitals, including aminoglycosides, ß-lactams, cationic peptides, chromoprotein enediyne antibiotics, dihydrofolate reductase inhibitors, fluoroquinolones and quinolones, glycopeptide antibiotics, macrolides, polyketides and sulfonamides. Similar to other P. putida clinical isolates the strain was sensitive to amikacin. To shed light on the broad pattern of antibiotic resistance, which is rarely found in clinical isolates of this species, the genome of this strain was sequenced and analysed. The study revealed that the determinants of multiple resistance are both chromosomally-borne as well as located on the pPC9 plasmid. Further analysis indicated that pPC9 has recruited antibiotic and biocide resistance genes from environmental microorganisms as well as from opportunistic and true human pathogens. The pPC9 plasmid is not self-transmissible, but can be mobilized by other bacterial plasmids making it capable of spreading antibiotic resistant determinants to new hosts.

  12. Update on antibiotic resistance in foodborne Lactobacillus and Lactococcus species

    Directory of Open Access Journals (Sweden)

    Chiara eDevirgiliis

    2013-10-01

    Full Text Available Lactobacilli represent a major Lactic Acid Bacteria (LAB component within the complex microbiota of fermented foods obtained from meat, dairy and vegetable sources. Lactococci, on the other hand, are typical of milk and fermented dairy products, which in turn represent the vast majority of fermented products. As is the case for all species originating from the environment, foodborne lactobacilli and lactococci consist of natural, uncharacterized strains, whose biodiversity depends on geographical origin, seasonality, animal feeding/plant growth conditions. Although a few species of opportunistic pathogens have been described in lactobacilli and lactococci, they are mostly non-pathogenic, Gram-positive bacteria displaying probiotic features. Since antibiotic resistant (AR strains do not constitute an immediate threat to human health, scientific interest for detailed studies on AR genes in these species has been greatly hindered. However, increasing evidence points at a crucial role for foodborne LAB as reservoir of potentially transmissible AR genes, underlining the need for further, more detailed studies aimed at identifying possible strategies to avoid AR spread to pathogens through fermented food consumption. The availability of a growing number of sequenced bacterial genomes has been very helpful in identifying the presence/distribution of mobile elements associated with AR genes, but open questions and knowledge gaps still need to be filled, underlining the need for systematic and datasharing approaches to implement both surveillance and mechanistic studies on transferability of AR genes. In the present review we report an update of the recent literature on AR in lactobacilli and lactococci following the 2006 EU-wide ban of the use of antibiotics as feed additives in animal farming, and we discuss the limits of the present knowledge in evaluating possible risks for human health.

  13. Antibiotic resistance of common pathogenic bacteria causing clinical Infection in geriatric department%老年病科患者临床感染细菌耐药性分析

    Institute of Scientific and Technical Information of China (English)

    徐卫刚; 沈瑜; 浦裕美; 徐伟民

    2011-01-01

    OBJECTIVE To analysis the distribution and antibiotic resistance of commom pathogenic bacteria in the patients with Clinical infection in Geriatrics Dept. METHODS An investigation of all bacteriology specimens was carried out in 2009. Microbial sensitivity tests were performed by K-B disk diffusion method and the data was analyzed by WHONET5.4. RESULTS The bacteriology detection rate of patients in Geriatrics Dept was 51.5 %.The top three clinical isolates of Gram-positive cocci were Staphylococcus aureus, Enterococcus faecalis and E.faecium, which were 100.0% sensitive to vancomycin. The top 3 Enterobacteriaceae bacteria were E. coli, Klebsiella pneumoniae and P. aeruginosa. Enterobacteriaceae was most sensitive to imipenem. Cefoperazone/sulbactam, which was inferior to carbapenem, was the most sensitive antibiotic. The detection rates of ESBLsproducing E. col i and K. pneumoniae were 48% and 18. 3%, respectively. The detection rate of MRSA was 62.8%. The drug sensitivity of the antibiotics which were added enzyme inhibitors to E. coli and K. pneumoniae was significantly higher than that without adding. CONCLUSIONS The antibiotic resistance of the pathogenic bacteria is very high in geriatrics department. Cefoperazone/sulbactam and vancomycin are the ideal antibiotics.%目的 探讨老年病科临床感染常见病原菌分布及耐药状况. 方法 对2009年老年病科所有细菌送检标本进行专项分析,药敏采用K-B纸片法,WHONET 5.4软件进行统计. 结果 老年病科患者细菌学检出率低,为51.5%;排在前3位的革兰阳性球菌分别是金黄色葡萄球菌(10.0%)、粪肠球菌(1.9%)、屎肠球菌(1.6%)均对万古霉素100.0%敏感,排在前3位的革兰阴性菌主要为大肠埃希菌(28.8%)、肺炎克雷伯菌(16.6%)、铜绿假单胞菌(16.4%)其对亚胺培南敏感率最高,头孢哌酮/舒巴坦是仅次于碳青霉烯类外最敏感的抗菌药物;产超广谱β-内酰胺酶的大肠埃希菌和肺炎克

  14. Pattern of Bacterial Pathogens and Their Susceptibility Isolated from Surgical Site Infections at Selected Referral Hospitals, Addis Ababa, Ethiopia

    Directory of Open Access Journals (Sweden)

    Walelign Dessie

    2016-01-01

    Full Text Available Background. The emergence of multidrug resistant bacterial pathogens in hospitals is becoming a challenge for surgeons to treat hospital acquired infections. Objective. To determine bacterial pathogens and drug susceptibility isolated from surgical site infections at St. Paul Specialized Hospital Millennium Medical College and Yekatit 12 Referral Hospital Medical College, Addis Ababa, Ethiopia. Methods. A cross-sectional study was conducted between October 2013 and March 2014 on 107 surgical site infected patients. Wound specimens were collected using sterile cotton swab and processed as per standard operative procedures in appropriate culture media; and susceptibility testing was done using Kirby-Bauer disc diffusion technique. The data were analyzed by using SPSS version 20. Result. From a total of 107 swabs collected, 90 (84.1% were culture positive and 104 organisms were isolated. E. coli (24 (23.1% was the most common organism isolated followed by multidrug resistant Acinetobacter species (23 (22.1%. More than 58 (75% of the Gram negative isolates showed multiple antibiotic resistance (resistance ≥ 5 drugs. Pan-antibiotic resistance was noted among 8 (34.8% Acinetobacter species and 3 (12.5% E. coli. This calls for abstinence from antibiotic abuse. Conclusion. Gram negative bacteria were the most important isolates accounting for 76 (73.1%. Ampicillin, amoxicillin, penicillin, cephazoline, and tetracycline showed resistance while gentamicin and ciprofloxacin were relatively effective antimicrobials.

  15. Antibiotic Resistance Related to Biofilm Formation in Klebsiella pneumoniae

    Directory of Open Access Journals (Sweden)

    Claudia Vuotto

    2014-09-01

    Full Text Available The Gram-negative opportunistic pathogen, Klebsiella pneumoniae, is responsible for causing a spectrum of community-acquired and nosocomial infections and typically infects patients with indwelling medical devices, especially urinary catheters, on which this microorganism is able to grow as a biofilm. The increasingly frequent acquisition of antibiotic resistance by K. pneumoniae strains has given rise to a global spread of this multidrug-resistant pathogen, mostly at the hospital level. This scenario is exacerbated when it is noted that intrinsic resistance to antimicrobial agents dramatically increases when K. pneumoniae strains grow as a biofilm. This review will summarize the findings about the antibiotic resistance related to biofilm formation in K. pneumoniae.

  16. Emerging antibiotic resistance in bacteria with special reference to India

    OpenAIRE

    Raghunath, D.

    2008-01-01

    The antibiotic era started in the 1940s and changed the profi le of infectious diseases and human demography. The burgeoning classes and numbers promised much and elimination of this major cause of human (and animal) morbidity appeared possible. Bacterial antibiotic resistance which was observed soon after antibiotic introduction has been studied extensively. Diverse mechanisms have been demonstrated and the genetic basis elucidated. The resilience of the prokaryote ecosystems to antibiotic s...

  17. Mechanisms of Helicobacter pylori antibiotic resistance and molecular testing

    OpenAIRE

    Toshihiro eNishizawa; Hidekazu eSuzuki

    2014-01-01

    Antibiotic resistance in Helicobacter pylori (H. pylori) is the main factor affecting the efficacy of current treatment methods against infection caused by this organism. The traditional culture methods for testing bacterial susceptibility to antibiotics are expensive and require 10 to 14 days. Since resistance to clarithromycin, fluoroquinolone, and tetracycline seems to be exclusively caused by specific mutations in a small region of the responsible gene, molecular methods offer an attracti...

  18. Insights from genomics into bacterial pathogen populations.

    Directory of Open Access Journals (Sweden)

    Daniel J Wilson

    2012-09-01

    Full Text Available Bacterial pathogens impose a heavy burden of disease on human populations worldwide. The gravest threats are posed by highly virulent respiratory pathogens, enteric pathogens, and HIV-associated infections. Tuberculosis alone is responsible for the deaths of 1.5 million people annually. Treatment options for bacterial pathogens are being steadily eroded by the evolution and spread of drug resistance. However, population-level whole genome sequencing offers new hope in the fight against pathogenic bacteria. By providing insights into bacterial evolution and disease etiology, these approaches pave the way for novel interventions and therapeutic targets. Sequencing populations of bacteria across the whole genome provides unprecedented resolution to investigate (i within-host evolution, (ii transmission history, and (iii population structure. Moreover, advances in rapid benchtop sequencing herald a new era of real-time genomics in which sequencing and analysis can be deployed within hours in response to rapidly changing public health emergencies. The purpose of this review is to highlight the transformative effect of population genomics on bacteriology, and to consider the prospects for answering abiding questions such as why bacteria cause disease.

  19. Detection of antibiotic resistance in probiotics of dietary supplements

    OpenAIRE

    Wong, Aloysius; Ngu, Davey Yueh Saint; Dan, Lydia Annabel; Ooi, Amanda; Lim, Renee Lay Hong

    2015-01-01

    Background Probiotics are live microorganisms that confer nutrition- and health-promoting benefits if consumed in adequate amounts. Concomitant with the demand for natural approaches to maintaining health is an increase in inclusion of probiotics in food and health products. Since probiotic bacteria act as reservoir for antibiotic resistant determinants, the transfer of these genes to pathogens sharing the same intestinal habitat is thus conceivable considering the fact that dietary supplemen...

  20. Bacteriophage Resistance Mechanisms in the Fish Pathogen Flavobacterium psychrophilum: Linking Genomic Mutations to Changes in Bacterial Virulence Factors

    DEFF Research Database (Denmark)

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Dalsgaard, Inger

    2015-01-01

    Flavobacterium psychrophilum is an important fish pathogen in salmonid aquaculture worldwide. Due to increased antibiotic resistance, pathogen control using bacteriophages has been explored as a possible alternative treatment. However, the effective use of bacteriophages in pathogen control...... requires overcoming the selection for phage resistance in the bacterial populations. Here, we analyzed resistance mechanisms in F. psychrophilum after phage exposure using whole-genome sequencing of the ancestral phage-sensitive strain 950106-1/1 and six phage-resistant isolates. The phage......-resistant strains had all obtained unique insertions and/or deletions and point mutations distributed among intergenic and genic regions. Mutations in genes related to cell surface properties, gliding motility, and biosynthesis of lipopolysaccharides and cell wall were found. The observed links between phage...

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

    Science.gov (United States)

    Capita, Rosa; Alonso-Calleja, Carlos

    2013-01-01

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

  2. Distribution and antibiotic resistance of pathogenic bacteria causing lower respiratory tract infection in ICU%ICU下呼吸道感染病原菌分布与耐药现状分析

    Institute of Scientific and Technical Information of China (English)

    金晓冰; 邓敏; 邹俊宁; 江新姣; 吴艳艳

    2011-01-01

    目的 了解重症监护病房(ICU)患者下呼吸道感染的病原菌分布和耐药谱,为临床治疗提供依据. 方法 入选2008年1月-2009年6月入住ICU下呼吸道感染患者,进行深部痰液病原菌培养,分析病原菌分布情况和耐药性. 结果 革兰阴性杆菌是下呼吸道感染的主要病原菌,占66.9%,以鲍氏不动杆菌占优势,为31.6%;革兰阳性球菌占10.3%,以金黄色葡萄球菌为主,占8.1%;真菌感染占22.8%,除真菌耐药率较低外,其他病原菌均有较高耐药性,多药耐药鲍氏不动杆菌检出率达69.8%. 结论 ICU下呼吸道感染病原菌的菌群分布发生了变化,真菌感染率上升,多药耐药菌增多,临床医师需密切关注分离菌的变迁及耐药情况,合理使用抗菌药物.%OBJECTIVE To investigate the distribution and antibiotic resistance status of pathogenic bacteria from lower respiratory tract in patients of intensive care unit (ICU) in hospital, and provide basis for rational selection of clinical drugs. METHODS Totally 89 cases of lower respiratory infection admitted to the ICU from Jan 2008 to Jun 2009 were reviewed. Pathogens in the sputum were isolated and indenified,and the distribution of pathogenic bactieria and their drug resistance profile were analyzed. RESULTS 66. 9 % of pathogenic bacteria were Gramnegative ones, among which Acinetobater baumannii occupy 31.6 %, 10.3 % were Gram-positive bacteria, Staphylococcus aureus (8. 1 %)was the most prominent bacteria. Fungi accounted for 22.8%. All pathogenic bacteria showed high resistance to the antibiotics but fungi. Multi-drug resistant (MDR) Acinetobater baumannii were test out with 69.8 % occurrence. CONCLUSION The pathogenic bacteria and their resistance to the antibiotic have been changed in ICU. The fungal infection rate is increased and there is an increasing trend in the detection rate of MDR. Clinicians should pay close attention to the changes and resistance of pathogenic bacteria and

  3. 儿童社区获得性肺炎病原体及细菌药敏结果分析%Pathogens and antibiotic resistance of community-acquired pneumonia in children

    Institute of Scientific and Technical Information of China (English)

    刘俊英

    2012-01-01

    Objective To investigate the pathogens and antibiotic resistance of community-acquired pneumonia (CAP) in children. Methods Pathogens were isolated from sputum specimens, drug sensitivity testing was done using the disc diffusion method (KB method) , and atypical pathogens and viruses were detected using immunofluorescence Results A total of 385 strains of pathogens were isolated from 651 children with CAP. These consisted of 142 strains of bacteria, 105 strains of viruses, and 138 strains of atypical pathogens. The pathogen most often detected was Mycoplasma pneumoniae (MP), with 108 strains delected. There were 54 strains of respiratory syncytial virus, 47 of hemophilus, 27 of parainfluenza virus, 23 of Chlamydiu pneumoniae , and 21 of Streptococcus pneumoniae. Eighty-nine children had a mixed infection. Hemophilus was resistant to ciprofloxacin and sensitive to azithromycin, vancomycin, and amoxicillin/clavu-lanate potassium. Conclusion MP was the predominant pathogen in children with community-acquired pneumonia. The isolates had little drug resistance.%目的 了解2011年医院儿童社区获得性肺炎(CAP)感染病原体类型及细菌的耐药情况. 方法 收集患儿痰液,进行菌种鉴定,KB纸片法进行药敏试验;非典型病原体、呼吸道合胞病毒等采用免疫荧光法检测鉴定. 结果 651例CAP患儿病原体感染385例,感染率为59.14%,其中检出细菌142株,病毒105株,非典型病原体138株.检出菌株数最多的是肺炎支原体,为108株(占28.05%),其次为呼吸道合胞病毒,为54株(占14.03%),其他病原体,如嗜血杆菌(47株),副流感病毒(27株),肺炎衣原体(23株)和肺炎链球菌(21株).患儿混合感染89例,以病毒和细菌混合感染为主.嗜血杆菌对环丙沙星耐药率最高,为55.32%;嗜血杆菌、肺炎链球菌和肺炎克雷伯菌对阿奇霉素、万古霉素、阿莫西林/克拉维酸敏感. 结论 CAP患儿以肺炎支原体感染为主,分离细菌对常见抗生素耐药性较低.

  4. Analysis of pathogen distribution and antibiotic resistance in 1606 blood cultures from neonates%1606例新生儿败血症病原菌分布及其耐药性分析

    Institute of Scientific and Technical Information of China (English)

    唐晓娟; 冯星

    2014-01-01

    Objective To determine the pathogen profile and antibiotic resistance in aerobic isolates from blood cultures of neonates. Methods All blood culture reports (n=28120) from newborns admitted to the Department of Neonatology during 2002-2012 were analyzed, and the sensitivity patterns were recorded. Results A total of 1665 bacteria were isolated from 1606 blood culture-positive samples and the positive rate of blood cultures was 5.7%(1606/28120). Gram-positive bacteria were iso-lated in 1336 cases, with Staphylococcus epidermidis (902 cases) and Staphylococcus haemolyticus (206 cases) being the com-mon bacteria. Klebsiella pneumoniae (108 cases), followed by Escherichia coli (73 cases), were the major Gram-negative bacte-ria (235 cases). The determination of the antibiotic resistance of aerobic isolates was performed in 2012. Most Gram-positive iso-lates were sensitive to vancomycin and moxifloxacin, and more than 90%were resistant to penicillin while most of Gram-nega-tive isolates were sensitive to amikacin and imipenem. Conclusions Staphylococcus epidermidis, Staphylococcus haemolyticus, Klebsiella pneumoniae and Escherichia coli remain to be the principal organisms responsible for neonatal sepsis.%目的:研究败血症新生儿的病原菌分布及其耐药情况。方法回顾性分析2002年至2012年间收入新生儿重症监护病房的新生儿血培养及其药敏分析结果。结果共28120份新生儿血培养标本中培养阳性1606份(5.7%),共培养出病原菌1665株;其中革兰阳性菌1336株,以表皮葡萄球菌(902株)及溶血性葡萄球菌(206株)为主;革兰阴性菌235株,以肺炎克雷伯杆菌(108株)及大肠埃希菌(73株)为主。逐年比较,不同菌株的检出率差异有统计学意义(P<0.05)。2012年175株病原菌的药敏结果显示,革兰阳性菌对利奈唑胺、替加环素和万古霉素的敏感率高,对青霉素耐药性达90%以上;革兰阴性菌对阿米卡星

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

    Science.gov (United States)

    Fraqueza, Maria João

    2015-11-06

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

  6. Antibiotic resistance is prevalent in an isolated cave microbiome.

    Directory of Open Access Journals (Sweden)

    Kirandeep Bhullar

    Full Text Available Antibiotic resistance is a global challenge that impacts all pharmaceutically used antibiotics. The origin of the genes associated with this resistance is of significant importance to our understanding of the evolution and dissemination of antibiotic resistance in pathogens. A growing body of evidence implicates environmental organisms as reservoirs of these resistance genes; however, the role of anthropogenic use of antibiotics in the emergence of these genes is controversial. We report a screen of a sample of the culturable microbiome of Lechuguilla Cave, New Mexico, in a region of the cave that has been isolated for over 4 million years. We report that, like surface microbes, these bacteria were highly resistant to antibiotics; some strains were resistant to 14 different commercially available antibiotics. Resistance was detected to a wide range of structurally different antibiotics including daptomycin, an antibiotic of last resort in the treatment of drug resistant Gram-positive pathogens. Enzyme-mediated mechanisms of resistance were also discovered for natural and semi-synthetic macrolide antibiotics via glycosylation and through a kinase-mediated phosphorylation mechanism. Sequencing of the genome of one of the resistant bacteria identified a macrolide kinase encoding gene and characterization of its product revealed it to be related to a known family of kinases circulating in modern drug resistant pathogens. The implications of this study are significant to our understanding of the prevalence of resistance, even in microbiomes isolated from human use of antibiotics. This supports a growing understanding that antibiotic resistance is natural, ancient, and hard wired in the microbial pangenome.

  7. 重症监护病房感染菌株种类及药敏分析%Analysis on pathogenic bacteria distribution and antibiotic resistance in the intensive care unit (ICU)

    Institute of Scientific and Technical Information of China (English)

    曾洪伟

    2011-01-01

    Objective To explore pathogenic bacteria distribution and antibiotic resistance in the intensive care unit (ICU) for the guidance of antibiotic clinical use of drug therapy. Methods From January 2009 ~ December 2010,the kinds of pathogens and results of susceptibility testing in patients of ICU were retrospectively reviewed. Results In 2009,215 pathogens were isolated,pathogenic Gram - negative bacilli were still dominated, accounted for 51.16%, Gram - positive cocci accounted for 26. 05 %, fungi accounted for 12. 56% of the total composition; Ultra - extended - spectrum β - lactamases (ESBLs) had a detection rate of 51.82% ,methicillin -resistant Staphylococcus aureus (MRSA) had a detection rate of 71.43%. In 2010,231 pathogens were isolated,pathogenic Gram -negative bacilli were still dominated, accounted for 54.55%, Gram -positive cocci accounted for 25.97% ,fungi accounted for 13.42% of the total composition;Ultra - extended - - spectrum β - lactamases (ESBLs) had a detection rate of 53.17%, methicillin - resistant Staphylococcus aureus (MRSA) had a detection rate of 76. 67%, there were no significant differences( P > 0. 05 ). Conclusion Gram - negative bacilli were predominant in ICU patients, Gram - negative bacilli were the highest resistance to Ampicillin,whereas were the lowest resistance to Imipenem;The gram - positive coccus were the highest resistance to Axithromycin,whereas were the lowest resistance to Vancomycin.%目的探讨重症监护病房(ICU)患者感染菌株的分布特点及耐药情况,为临床选用抗菌药物治疗提供可靠依据.方法 分析2009年1月至2010年12月本院ICU患者送检的各类标本中分离出的病原菌和药物敏感试验结果.结果 2009年,分离出病原菌215株,病原菌以革兰阴性杆菌为主,占51.16%,革兰阳性球菌占26.05%,真菌占12.56%;超广谱β-内酰胺酶(ESBLs)检出率51.82%,耐甲氧西林葡萄球菌(MRSA)检出率71.43%.2010年,分离出病原菌231

  8. Emerging bacterial pathogens: the past and beyond.

    Science.gov (United States)

    Vouga, M; Greub, G

    2016-01-01

    Since the 1950s, medical communities have been facing with emerging and reemerging infectious diseases, and emerging pathogens are now considered to be a major microbiologic public health threat. In this review, we focus on bacterial emerging diseases and explore factors involved in their emergence as well as future challenges. We identified 26 major emerging and reemerging infectious diseases of bacterial origin; most of them originated either from an animal and are considered to be zoonoses or from water sources. Major contributing factors in the emergence of these bacterial infections are: (1) development of new diagnostic tools, such as improvements in culture methods, development of molecular techniques and implementation of mass spectrometry in microbiology; (2) increase in human exposure to bacterial pathogens as a result of sociodemographic and environmental changes; and (3) emergence of more virulent bacterial strains and opportunistic infections, especially affecting immunocompromised populations. A precise definition of their implications in human disease is challenging and requires the comprehensive integration of microbiological, clinical and epidemiologic aspects as well as the use of experimental models. It is now urgent to allocate financial resources to gather international data to provide a better understanding of the clinical relevance of these waterborne and zoonotic emerging diseases.

  9. Bacteriophages as potential treatment option for antibiotic resistant bacteria.

    Science.gov (United States)

    Bragg, Robert; van der Westhuizen, Wouter; Lee, Ji-Yun; Coetsee, Elke; Boucher, Charlotte

    2014-01-01

    The world is facing an ever-increasing problem with antibiotic resistant bacteria and we are rapidly heading for a post-antibiotic era. There is an urgent need to investigate alterative treatment options while there are still a few antibiotics left. Bacteriophages are viruses that specifically target bacteria. Before the development of antibiotics, some efforts were made to use bacteriophages as a treatment option, but most of this research stopped soon after the discovery of antibiotics. There are two different replication options which bacteriophages employ. These are the lytic and lysogenic life cycles. Both these life cycles have potential as treatment options. There are various advantages and disadvantages to the use of bacteriophages as treatment options. The main advantage is the specificity of bacteriophages and treatments can be designed to specifically target pathogenic bacteria while not negatively affecting the normal microbiota. There are various advantages to this. However, the high level of specificity also creates potential problems, the main being the requirement of highly specific diagnostic procedures. Another potential problem with phage therapy includes the development of immunity and limitations with the registration of phage therapy options. The latter is driving research toward the expression of phage genes which break the bacterial cell wall, which could then be used as a treatment option. Various aspects of phage therapy have been investigated in studies undertaken by our research group. We have investigated specificity of phages to various avian pathogenic E. coli isolates. Furthermore, the exciting NanoSAM technology has been employed to investigate bacteriophage replication and aspects of this will be discussed.

  10. Detection of antibiotic-resistant bacteria endowed with antimicrobial activity from a freshwater lake and their phylogenetic affiliation

    Directory of Open Access Journals (Sweden)

    Zothanpuia

    2016-06-01

    Full Text Available Antimicrobial resistance poses a serious challenge to global public health. In this study, fifty bacterial strains were isolated from the sediments of a freshwater lake and were screened for antibiotic resistance. Out of fifty isolates, thirty-three isolates showed resistance against at least two of the selected antibiotics. Analysis of 16S rDNA sequencing revealed that the isolates belonged to ten different genera, namely Staphylococcus(n = 8, Bacillus(n = 7, Lysinibacillus(n = 4, Achromobacter(n=3, bacterium(n = 3, Methylobacterium(n = 2, Bosea(n = 2, Aneurinibacillus(n = 2, Azospirillum(n = 1, Novosphingobium(n = 1. Enterobacterial repetitive intergenic consensus (ERIC and BOX-PCR markers were used to study the genetic relatedness among the antibiotic resistant isolates. Further, the isolates were screened for their antimicrobial activity against bacterial pathogens viz., Staphylococcus aureus(MTCC-96, Pseudomonas aeruginosa(MTCC-2453 and Escherichia coli(MTCC-739, and pathogenic fungi viz., Fusarium proliferatum (MTCC-286, Fusarium oxysporum (CABI-293942 and Fusarium oxy. ciceri (MTCC-2791. In addition, biosynthetic genes (polyketide synthase II (PKS-II and non-ribosomal peptide synthetase (NRPS were detected in six and seven isolates, respectively. This is the first report for the multifunctional analysis of the bacterial isolates from a wetland with biosynthetic potential, which could serve as potential source of useful biologically active metabolites.

  11. Exploring the contribution of bacteriophages to antibiotic resistance.

    Science.gov (United States)

    Lekunberri, Itziar; Subirats, Jèssica; Borrego, Carles M; Balcázar, José Luis

    2017-01-01

    Bacteriophages (phages) are the most abundant and diverse biological entities in our planet. They infect susceptible bacterial hosts into which they either multiply or persist. In the latter case, phages can confer new functions to their hosts as a result of gene transfer, thus contributing to their adaptation (short-term) and evolution (long-term). In this regard, the role of phages on the dissemination of antibiotic resistance genes (ARGs) among bacterial hosts in natural environments has not yet been clearly resolved. Here, we carry out a comprehensive analysis of thirty-three viromes from different habitats to investigate whether phages harbor ARGs. Our results demonstrate that while human-associated viromes do not or rarely carry ARGs, viromes from non-human sources (e.g. pig feces, raw sewage, and freshwater and marine environments) contain a large reservoir of ARGs, thus pointing out that phages could play a part on the spread of antibiotic resistance. Given this, the role of phages should not be underestimated and it should be considered when designing strategies to tackle the global crisis of antibiotic resistance.

  12. Transport and transformation of genetic information in the critical zone: The case of antibiotic resistance genes

    Science.gov (United States)

    Zhu, Y. G.

    2015-12-01

    In addition to material and energy flows, the dynamics and functions of the Earth's critical zone are intensively mediated by biological actions performed by diverse organisms. These biological actions are modulated by the expression of functional genes and their translation into enzymes that catalyze geochemical reactions, such as nutrient turnover and pollutant biodegradation. Although geobiology, as an interdisciplinary research area, is playing and vital role in linking biological and geochemical processes at different temporal and spatial scales, the distribution and transport of functional genes have rarely been investigated from the Earth's critical zone perspectives. To illustrate the framework of studies on the transport and transformation of genetic information in the critical zone, antibiotic resistance is taken as an example. Antibiotic resistance genes are considered as a group of emerging contaminants, and their emergence and spread within the critical zone on one hand are induced by anthropogenic activities, and on other hand are threatening human health worldwide. The transport and transformation of antibiotic resistance genes are controlled by both horizontal gene transfer between bacterial cells and the movement of bacteria harboring antibiotic resistance genes. In this paper, the fate and behavior of antibiotic resistance genes will be discussed in the following aspects: 1) general overview of environmental antibiotic resistance; 2) high through quantification of the resistome in various environmental media; 3) pathways of resistance gene flow within the critical zone; and 4) potential strategies in mitigating antibiotic resistance, particularly from the critical zone perspectives.

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

    Science.gov (United States)

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

    2016-02-01

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

  14. Improved annotation of antibiotic resistance determinants reveals microbial resistomes cluster by ecology.

    Science.gov (United States)

    Gibson, Molly K; Forsberg, Kevin J; Dantas, Gautam

    2015-01-01

    Antibiotic resistance is a dire clinical problem with important ecological dimensions. While antibiotic resistance in human pathogens continues to rise at alarming rates, the impact of environmental resistance on human health is still unclear. To investigate the relationship between human-associated and environmental resistomes, we analyzed functional metagenomic selections for resistance against 18 clinically relevant antibiotics from soil and human gut microbiota as well as a set of multidrug-resistant cultured soil isolates. These analyses were enabled by Resfams, a new curated database of protein families and associated highly precise and accurate profile hidden Markov models, confirmed for antibiotic resistance function and organized by ontology. We demonstrate that the antibiotic resistance functions that give rise to the resistance profiles observed in environmental and human-associated microbial communities significantly differ between ecologies. Antibiotic resistance functions that most discriminate between ecologies provide resistance to β-lactams and tetracyclines, two of the most widely used classes of antibiotics in the clinic and agriculture. We also analyzed the antibiotic resistance gene composition of over 6000 sequenced microbial genomes, revealing significant enrichment of resistance functions by both ecology and phylogeny. Together, our results indicate that environmental and human-associated microbial communities harbor distinct resistance genes, suggesting that antibiotic resistance functions are largely constrained by ecology.

  15. Formaldehyde stress responses in bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Nathan Houqian Chen

    2016-03-01

    Full Text Available Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed.

  16. Detection of antibiotic resistance in probiotics of dietary supplements

    KAUST Repository

    Wong, Aloysius Tze

    2015-09-14

    Background Probiotics are live microorganisms that confer nutrition- and health-promoting benefits if consumed in adequate amounts. Concomitant with the demand for natural approaches to maintaining health is an increase in inclusion of probiotics in food and health products. Since probiotic bacteria act as reservoir for antibiotic resistant determinants, the transfer of these genes to pathogens sharing the same intestinal habitat is thus conceivable considering the fact that dietary supplements contain high amounts of often heterogeneous populations of probiotics. Such events can confer pathogens protection against commonly-used drugs. Despite numerous reports of antibiotic resistant probiotics in food and biological sources, the antibiogram of probiotics from dietary supplements remained elusive. Findings Here, we screened five commercially available dietary supplements for resistance towards antibiotics of different classes. Probiotics of all batches of products were resistant towards vancomycin while batch-dependent resistance towards streptomycin, aztreonam, gentamycin and/or ciprofloxacin antibiotics was detected for probiotics of brands Bi and Bn, Bg, and L. Isolates of brand Cn was also resistant towards gentamycin, streptomycin and ciprofloxacin antibiotics. Additionally, we also report a discrepancy between the enumerated viable bacteria amounts and the claims of the manufacturers. Conclusions This short report has highlighted the present of antibiotic resistance in probiotic bacteria from dietary supplements and therefore serves as a platform for further screenings and for in-depth characterization of the resistant determinants and the molecular machinery that confers the resistance.

  17. Helicobacter pylori and Antibiotic Resistance, A Continuing and Intractable Problem.

    Science.gov (United States)

    Hu, Yue; Zhang, Meng; Lu, Bin; Dai, Jinfeng

    2016-10-01

    Helicobacter pylori, a human pathogen with a high global prevalence, is the causative pathogen for multiple gastrointestinal diseases, especially chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric malignancies. Antibiotic therapies remain the mainstay for H. pylori eradication; however, this strategy is hampered by the emergence and spread of H. pylori antibiotic resistance. Exploring the mechanistic basis of this resistance is becoming one of the major research questions in contemporary biomedical research, as such knowledge could be exploited to devise novel rational avenues for counteracting the existing resistance and devising strategies to avoid the development of a novel anti-H. pylori medication. Encouragingly, important progress in this field has been made recently. Here, we attempt to review the current state and progress with respect to the molecular mechanism of antibiotic resistance for H. pylori. A picture is emerging in which mutations of various genes in H. pylori, resulting in decreased membrane permeability, altered oxidation-reduction potential, and a more efficient efflux pump system. The increased knowledge on these mechanisms produces hope that antibiotic resistance in H. pylori can ultimately be countered.

  18. Targets for Combating the Evolution of Acquired Antibiotic Resistance.

    Science.gov (United States)

    Culyba, Matthew J; Mo, Charlie Y; Kohli, Rahul M

    2015-06-16

    Bacteria possess a remarkable ability to rapidly adapt and evolve in response to antibiotics. Acquired antibiotic resistance can arise by multiple mechanisms but commonly involves altering the target site of the drug, enzymatically inactivating the drug, or preventing the drug from accessing its target. These mechanisms involve new genetic changes in the pathogen leading to heritable resistance. This recognition underscores the importance of understanding how such genetic changes can arise. Here, we review recent advances in our understanding of the processes that contribute to the evolution of antibiotic resistance, with a particular focus on hypermutation mediated by the SOS pathway and horizontal gene transfer. We explore the molecular mechanisms involved in acquired resistance and discuss their viability as potential targets. We propose that additional studies into these adaptive mechanisms not only can provide insights into evolution but also can offer a strategy for potentiating our current antibiotic arsenal.

  19. Controlling antibiotic resistance in the ICU

    NARCIS (Netherlands)

    Derde, L.P.G.

    2013-01-01

    Patients admitted to intensive care units (ICUs) are frequently colonized with (antibiotic-resistant) bacteria, which may lead to healthcare associated infections. Antimicrobial-resistant bacteria (AMRB), such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (V

  20. Analysis of antibiotic-resistant gene mecA and pathogenic genes in Staphylococcus aureus%金黄色葡萄球菌耐药基因及致病毒素基因的研究

    Institute of Scientific and Technical Information of China (English)

    王凤玲; 刘静; 杨青

    2009-01-01

    目的 研究金葡菌耐药基因及致病因子中毒休克综合征毒素-Ⅰ(TSST-Ⅰ)基因和杀白细胞毒素 (PVL) 基因的分布特征.方法 收集临床分离的74株金葡菌,PCR法检测毒素基因TSST-Ⅰ、PVL和mecA耐药基因.结果 74株金葡菌 PCR法对其行mecA基因检测,检出率为55.4% (41/74).PVL阳性菌株的分离率为29.7%(22/74),PVL阳性的MRSA为15株(15/41,36.6%), PVL阳性的MSSA为7株(7/33,21.2%),差异无统计学意义(P>0.05).TSST-Ⅰ基因检出率为6.8%, MSSA中未检出TSST-Ⅰ基因.结论 MRSA呈多重耐药性,易造成医院内暴发流行,携带PVL和TSST-Ⅰ的金葡菌其致病力更强,应加强医院感染控制,防止其播散流行.%Objective To investigate the antibiotic-resistant gene mecA and the prevalence of Panton-Valentine leukocidin (PVL) gene, toxic shock syndrome toxin (TSST-Ⅰ) gene in S. aureus. Methods A total of 74 S. aureus were collected from clinical specimens. The mecA, PVL and TSST-Ⅰ genes were detected by PCR.Results PVL gene was identified in 22 S. aureus isolates. The prevalence of PVL was 29.7% in S. aureus, 36.6% in MRSA and 21.2% in MSSA. The difference was not statistically significant (P>0.05). The prevalence of MRSA was 55.4% in 74 S. aureus. The prevalence of TSST-Ⅰ gene was 6.8%. TSST-Ⅰ gene was not detected in MSSA.Conclusions MRSA strains show highly resistant to antibiotics. PVL- and TSST-Ⅰ-positive S. aureus are more pathogenic.

  1. Prevalence and antibiotic resistance of Campylobacter, Salmonella, and L. monocytogenes in ducks: a review.

    Science.gov (United States)

    Adzitey, Frederick; Huda, Nurul; Ali, Gulam Rusul Rahmat

    2012-06-01

    Campylobacter, Salmonella, and Listeria monocytogenes are important bacterial pathogens associated with gastroenteritis. The consumption of poultry meat and their products is considered as a major and leading source of human infection. While surveys of chicken meat and products, and its association with foodborne pathogens are widely available, such information on ducks is scarce. This survey examines the prevalence and antibiotic resistance of Campylobacter, Salmonella and L. monocytogenes isolated from ducks. Data obtained from key surveys are summarized. The observed prevalence of these pathogens and their resistance to various antibiotics varies from one study to the other. The mean prevalence (and range means from individual surveys) are duck 53.0% (0.0-83.3%), duck meat and parts 31.6% (12.5-45.8%), and duck rearing and processing environment 94.4% (92.0-96.7%) for Campylobacter spp. For Salmonella spp., the mean prevalence data are duck 19.9% (3.3-56.9%), duck meat and parts 28.4% (4.4-75.6%), duck egg, shell, and content 17.5% (0-4.17%), and duck rearing and processing environment 32.5% (10.5-82.6%). Studies on the prevalence and antibiotic resistance of L. monocytogenes in ducks are by far very rare compared to Campylobacter and Salmonella, although ducks have been noted to be a potential source for these foodborne pathogens. From our survey, ducks were more frequently contaminated with Campylobacter than Salmonella. Campylobacter and Salmonella spp. also exhibited varying resistance to multiple antibiotics.

  2. The determinants of the antibiotic resistance process

    Directory of Open Access Journals (Sweden)

    Beatriz Espinosa Franco

    2009-04-01

    Full Text Available Beatriz Espinosa Franco1, Marina Altagracia Martínez2, Martha A Sánchez Rodríguez1, Albert I Wertheimer31Facultad de Estudios Superiores Zaragoza (UNAM, Mexico; 2Universidad Autónoma Metropolitana Unidad Xochimilco, Mexico; 3Temple University, Philadelphia, Pennsylvania, USABackground: The use of antibiotic drugs triggers a complex interaction involving many biological, sociological, and psychological determinants. Resistance to antibiotics is a serious worldwide problem which is increasing and has implications for morbidity, mortality, and health care both in hospitals and in the community.Objectives: To analyze current research on the determinants of antibiotic resistance and comprehensively review the main factors in the process of resistance in order to aid our understanding and assessment of this problem.Methods: We conducted a MedLine search using the key words “determinants”, “antibiotic”, and “antibiotic resistance” to identify publications between 1995 and 2007 on the determinants of antibiotic resistance. Publications that did not address the determinants of antibiotic resistance were excluded.Results: The process and determinants of antibiotic resistance are described, beginning with the development of antibiotics, resistance and the mechanisms of resistance, sociocultural determinants of resistance, the consequences of antibiotic resistance, and alternative measures proposed to combat antibiotic resistance.Conclusions: Analysis of the published literature identified the main determinants of antibiotic resistance as irrational use of antibiotics in humans and animal species, insufficient patient education when antibiotics are prescribed, lack of guidelines for treatment and control of infections, lack of scientific information for physicians on the rational use of antibiotics, and lack of official government policy on the rational use of antibiotics in public and private hospitals.Keywords: antibiotic drug resistance

  3. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004

    DEFF Research Database (Denmark)

    Hendriksen, Rene S.; Mevius, Dik J; Schroeter, Andreas

    2008-01-01

    Background: The project "Antibiotic resistance in bacteria of animal origin - II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003 - 2005, with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories...... in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected. Method: Antimicrobial susceptibility data for several bovine pathogens were obtained over a three year period...... from 13 European countries. For Staphylococcus aureus from bovine mastitis major differences were apparent in the occurrence of resistance between countries and between the different antimicrobial agents tested. The highest frequency of resistance was observed for penicillin. For Mannheimia haemolytica...

  4. Assessing Antibiotic Resistance of Staphyloccocus: Students Use Their Own Microbial Flora To Explore Antibiotic Resistance.

    Science.gov (United States)

    Omoto, Charlotte K.; Malm, Kirstin

    2003-01-01

    Describes a microbiology laboratory experiment in which students test their own microbial flora of Staphylococcus for antibiotic resistance. Provides directions on how to conduct the experiment. (YDS)

  5. Membrane permeability, a pivotal function involved in antibiotic resistance and virulence in Enterobacter aerogenes clinical isolates.

    Science.gov (United States)

    Lavigne, J-P; Sotto, A; Nicolas-Chanoine, M-H; Bouziges, N; Bourg, G; Davin-Regli, A; Pagès, J-M

    2012-06-01

    Imipenem-susceptible E. aerogenes isolates exhibiting extended spectrum β-lactamases, target mutations and a basal efflux expression, were identified in five patients. After imipenem treatment, imipenem-intermediate susceptible (IMI-I) or resistant (IMI-R) isolates emerged in these patients. Alteration in porin synthesis and increase in efflux expression were observed in the IMI-I isolates whereas complete loss of the porins, LPS alteration and efflux overexpression were observed in the IMI-R isolates. Bacterial virulence of the strains was investigated by the Caenorhabditis elegans model. The IMI-R isolates were shown to be significantly less virulent than the IMI-susceptible or IMI-I isolates. The pleiotropic membrane alteration and its associated fitness burden exhibited by E. aerogenes isolates influence their antibiotic resistance and their virulence behaviour. These findings highlight the balance between the low permeability-related resistance and virulence and their relationships with the treatment of resistant pathogens.

  6. Surveillant antibiotic resistant bacterial strians in hospital infection for choosing antibiotics of empirical therapy%细菌耐药性检测在细菌性感染经验治疗中的作用

    Institute of Scientific and Technical Information of China (English)

    李家娅

    2009-01-01

    目的 为细菌性感染经验治疗提供依据.方法 应用Kirby-Bauer扩散法检测28种属620株菌对14种抗菌药物的耐药百分率,用Nitrocefin测试β-内酰胺酶.结果 革兰氏阴性杆菌中亚胺培南耐药率最低(0~4.3%),氨苄西林耐药率最高(58.3%~96.7%).革兰氏阳性球菌万古霉素耐药率最低(0~7.1%),苯唑西林耐药率最高(5.3%~90.7%)(甲氧苯西林敏感金黄色葡萄球菌、甲氧苯西林敏感凝固酶阴性葡萄球菌和肺炎球菌除外).结论 经验治疗应选用对病原菌耐药率低、单一抗菌药物或联合使用的两种药物.%Objective To choose antibiotics for empirical therapy of bacterial infection. Methods Six hundrend and twenty strians including 28 genus and species were studied with kirby Bauer diffusion method. Results The resistant rates of 620 strians versus 14 kinds of antibiotics and the clata of multi -resistant strians and β -lactamas positive strians were shown. Among the gram negative rods, the maximum antibiotic resis - tant rate (Max. A. R. R.) of imipenem 0 - 4.3%, and the minimum antibiotic resistant rate (Min A. R. R.) of ampicillin 58.3% -96.7%. Among the gram positive cocci,the Max. A. R. R of vacomycin was 0 - 17.1% ,and the Min. A.R.R. of oxicillin 5.3% -90.7% (except MSSA, MSCNS and strepto - coccus pneumoniae). Conclusions The clinicians should choose an antibiotic of low resistant rate or acombined use of two antibiotics for the empirical therapy of bactericl infection.

  7. Evaluating the mobility potential of antibiotic resistance genes in environmental resistomes without metagenomics

    Science.gov (United States)

    Pärnänen, Katariina; Karkman, Antti; Tamminen, Manu; Lyra, Christina; Hultman, Jenni; Paulin, Lars; Virta, Marko

    2016-01-01

    Antibiotic resistance genes are ubiquitous in the environment. However, only a fraction of them are mobile and able to spread to pathogenic bacteria. Until now, studying the mobility of antibiotic resistance genes in environmental resistomes has been challenging due to inadequate sensitivity and difficulties in contig assembly of metagenome based methods. We developed a new cost and labor efficient method based on Inverse PCR and long read sequencing for studying mobility potential of environmental resistance genes. We applied Inverse PCR on sediment samples and identified 79 different MGE clusters associated with the studied resistance genes, including novel mobile genetic elements, co-selected resistance genes and a new putative antibiotic resistance gene. The results show that the method can be used in antibiotic resistance early warning systems. In comparison to metagenomics, Inverse PCR was markedly more sensitive and provided more data on resistance gene mobility and co-selected resistances. PMID:27767072

  8. Antibiotic resistance-the need for global solutions.

    Science.gov (United States)

    Laxminarayan, Ramanan; Duse, Adriano; Wattal, Chand; Zaidi, Anita K M; Wertheim, Heiman F L; Sumpradit, Nithima; Vlieghe, Erika; Hara, Gabriel Levy; Gould, Ian M; Goossens, Herman; Greko, Christina; So, Anthony D; Bigdeli, Maryam; Tomson, Göran; Woodhouse, Will; Ombaka, Eva; Peralta, Arturo Quizhpe; Qamar, Farah Naz; Mir, Fatima; Kariuki, Sam; Bhutta, Zulfiqar A; Coates, Anthony; Bergstrom, Richard; Wright, Gerard D; Brown, Eric D; Cars, Otto

    2013-12-01

    The causes of antibiotic resistance are complex and include human behaviour at many levels of society; the consequences affect everybody in the world. Similarities with climate change are evident. Many efforts have been made to describe the many different facets of antibiotic resistance and the interventions needed to meet the challenge. However, coordinated action is largely absent, especially at the political level, both nationally and internationally. Antibiotics paved the way for unprecedented medical and societal developments, and are today indispensible in all health systems. Achievements in modern medicine, such as major surgery, organ transplantation, treatment of preterm babies, and cancer chemotherapy, which we today take for granted, would not be possible without access to effective treatment for bacterial infections. Within just a few years, we might be faced with dire setbacks, medically, socially, and economically, unless real and unprecedented global coordinated actions are immediately taken. Here, we describe the global situation of antibiotic resistance, its major causes and consequences, and identify key areas in which action is urgently needed.

  9. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  10. CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    S. Thangapandiyan and P. Prema*

    2012-05-01

    Full Text Available Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100µL/disc, the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%, Escherichia coli (62.50%, and Staphylococcus aureus (46% followed by rifampicin against Bacillus cereus (66.67% and kanamycin against Streptococcus epidermis (25%. These results signify that the silver nanoparticles showed potential antibacterial action of ß-lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.

  11. ABC-F Proteins Mediate Antibiotic Resistance through Ribosomal Protection.

    Science.gov (United States)

    Sharkey, Liam K R; Edwards, Thomas A; O'Neill, Alex J

    2016-03-22

    Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to anin vitrotranslation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosomein vitro To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection.IMPORTANCEAntimicrobial resistance ranks among the greatest threats currently facing human health. Elucidation of the mechanisms by which microorganisms resist the effect of antibiotics is central to understanding the biology of this phenomenon and has the potential to inform the development of new drugs capable of blocking or circumventing resistance. Members of the ABC-F family, which includelsa(A),msr(A),optr(A), andvga(A), collectively yield resistance to a broader range of clinically significant antibiotic classes than any other family of resistance determinants, although their mechanism of action has been controversial since their discovery 25 years ago. Here we present the first direct evidence that proteins of the ABC-F family act to protect the bacterial ribosome from antibiotic-mediated inhibition.

  12. Chemical Countermeasures for Antibiotic Resistance

    Science.gov (United States)

    2014-04-01

    SUPPLEMENTARY NOTES 14.ABSTRACT New approaches are required to control multi-drug resistant (MDR) bacterial infections in military medical facilities ...New approaches are required to control multi-drug resistant (MDR) bacterial infections in military medical facilities , as injured Warfighters...current position: postdoc in the Disney lab TSRI Florida 15 CONCLUSION: New approaches are desperately required to control multi-drug resistant

  13. Bacterial distribution and antibiotic resistance analysis of 352 positive blood-culture samples%血培养阳性标本352份的细菌分布及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    董筱莉; 殷莹

    2012-01-01

    目的 了解血培养阳性标本细菌分布及耐药情况,为菌血症、败血症的诊断及临床用药提供依据.方法 回顾分析2011年江阴市人民医院住院及门诊病人送检的血培养阳性标本.采用美国BD公司的BACTEC9120全自动血培养仪及法国梅里埃公司的VITEK32全自动细菌分析仪对阳性标本进行鉴定及药敏试验.结果 352份血培养阳性标本中革兰阳性菌173株,占49.15%;以表皮葡萄球菌、溶血性葡萄球菌、金黄色葡萄球菌为主,对大多数试验药物敏感性较高,但对青霉素均耐药.革兰阴性菌176株,占50.00%;以大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌为主,除铜绿假单胞菌耐药性较高外,其他2种菌对多数抗菌药敏感程度较高.另外,还检出1株白假丝酵母菌,1株热带假丝酵母菌,1株厌氧菌.结论 血培养分离的病原菌中革兰阳性菌与革兰阴性菌所占比率差别不大,但病原菌种类较多,根据耐药试验结果,提示应高度重视合理使用抗菌药物,减少细菌耐药性产生,以提高临床治疗效果.%[Objective] To understand the bacterial distribution and antibiotic resistance of blood-culture samples, and provide evidence for diagnosis and clinical treatment of bacteremia and sepsis. [Methods] Retrospective analysis was performed on positive blood-culture samples collected from inpatients and outpatients of Jiangyin People's Hospital in 2011. The identification and susceptibility testing were performed by BD BACTEC9120 automated blood culture system and Merieux VITEK32 fully automated bacterial analyzer. [Results] Of 352 samples, 173 (49. 15% ) were Gram-positive, the major were staphylococcus, Hemolytic staphylococcus and Staphylococcus aureus which were sensitive to most antibiotics, but resistant to penicillin; 176 (50. 00) were Gram-negative, most were Escherichia coli , Klebsiella pneumoniae and Pseudomonas aeruginosa, except Pseudomonas aeruginosa, the others were

  14. Carriage of antibiotic-resistant enteric bacteria varies among sites in Galapagos reptiles.

    Science.gov (United States)

    Wheeler, Emily; Hong, Pei-Ying; Bedon, Lenin Cruz; Mackie, Roderick I

    2012-01-01

    Increased overlap between humans and wildlife populations has increased the risk for novel disease emergence. Detecting contacts with a high risk for transmission of pathogens requires the identification of dependable measures of microbial exchange. We evaluated antibiotic resistance as a molecular marker for the intensity of human-wildlife microbial connectivity in the Galápagos Islands. We isolated Escherichia coli and Salmonella enterica from the feces of land iguanas (Conolophus sp.), marine iguanas (Amblyrhynchus cristatus), giant tortoises (Geochelone nigra), and seawater, and tested these bacteria with the use of the disk diffusion method for resistance to 10 antibiotics. Antibiotic-resistant bacteria were found in reptile feces from two tourism sites (Isla Plaza Sur and La Galapaguera on Isla San Cristóbal) and from seawater close to a public use beach near Puerto Baquerizo Moreno on Isla San Cristóbal. No resistance was detected at two protected beaches on more isolated islands (El Miedo on Isla Santa Fe and Cape Douglas on Isla Fernandina) and at a coastal tourism site (La Lobería on Isla San Cristóbal). Eighteen E. coli isolates from three locations, all sites relatively proximate to a port town, were resistant to ampicillin, doxycycline, tetracycline, and trimethoprin/sulfamethoxazole. In contrast, only five S. enterica isolates showed a mild decrease in susceptibility to doxycycline and tetracycline from these same sites (i.e., an intermediate resistance phenotype), but no clinical resistance was detected in this bacterial species. These findings suggest that reptiles living in closer proximity to humans potentially have higher exposure to bacteria of human origin; however, it is not clear from this study to what extent this potential exposure translates to ongoing exchange of bacterial strains or genetic traits. Resistance patterns and bacterial exchange in this system warrant further investigation to understand better how human associations

  15. Bioaerosol emissions and detection of airborne antibiotic resistance genes from a wastewater treatment plant

    Science.gov (United States)

    Li, Jing; Zhou, Liantong; Zhang, Xiangyu; Xu, Caijia; Dong, Liming; Yao, Maosheng

    2016-01-01

    Air samples from twelve sampling sites (including seven intra-plant sites, one upwind site and four downwind sites) from a wastewater treatment plant (WWTP) in Beijing were collected using a Reuter Centrifugal Sampler High Flow (RCS); and their microbial fractions were studied using culturing and high throughput gene sequence. In addition, the viable (fluorescent) bioaerosol concentrations for 7 intra-plant sites were also monitored for 30 min each using an ultraviolet aerodynamic particle sizer (UV-APS). Both air and water samples collected from the plant were investigated for possible bacterial antibiotic resistance genes and integrons using polymerase chain reaction (PCR) coupled with gel electrophoresis. The results showed that the air near sludge thickening basin was detected to have the highest level of culturable bacterial aerosols (up to 1697 CFU/m3) and fungal aerosols (up to 930 CFU/m3). For most sampling sites, fluorescent peaks were observed at around 3-4 μm, except the office building with a peak at 1.5 μm, with a number concentration level up to 1233-6533 Particles/m3. About 300 unique bacterial species, including human opportunistic pathogens, such as Comamonas Testosteroni and Moraxella Osloensis, were detected from the air samples collected over the biological reaction basin. In addition, we have detected the sul2 gene resistant to cotrimoxazole (also known as septra, bactrim and TMP-SMX) and class 1 integrase gene from the air samples collected from the screen room and the biological reaction basin. Overall, the screen room, sludge thickening basin and biological reaction basin imposed significant microbial exposure risks, including those from airborne antibiotic resistance genes.

  16. Potential use of Bacillus thuringiensis bacteriocins to control antibiotic-resistant bacteria associated with mastitis in dairy goats.

    Science.gov (United States)

    Gutiérrez-Chávez, A J; Martínez-Ortega, E A; Valencia-Posadas, M; León-Galván, M F; de la Fuente-Salcido, N M; Bideshi, D K; Barboza-Corona, J E

    2016-01-01

    Mastitis caused by microbial infections in dairy goats reduces milk yield, modifies milk composition, and potentially contributes to morbidity in herds and consumers of dairy products. Microorganisms associated with mastitis in dairy goats are commonly controlled with antibiotics, but it is known that continued use of these chemical agents promotes antibiotic resistance among bacterial populations. Recently, it has been shown that bacteriocins of Bacillus thuringiensis inhibit growth of food-borne pathogens and also bacteria associated with bovine mastitis. However, there is no report on their ability to inhibit microorganisms linked to mastitis in dairy goats. In this study, using 16S rDNA and ITS regions of rDNA, we identified nine bacterial isolates and an encapsulated yeast associated with mastitis in dairy goats. Enterococcus durans, Brevibacillus sp., and Staphylococcus epidermidis 2 were resistant to, respectively, 75, ~67, ~42, and ~42 % of the antibiotics screened. In addition, 60 % of the bacterial isolates were resistant to penicillin, ampicillin, vancomycin, and dicloxacillin. Importantly, 60 % of the isolates were inhibited by the bacteriocins, but S. epidermidis 1, Enterobacter sp., Escherichia vulneris, and Cryptococcus neoformans were not susceptible to these antimicrobial peptides. Using Brevibacillus sp. and Staphylococcus chromogenes as indicator bacteria, we show that peptides of ~10 kDa that correspond to the molecular mass of bacteriocins used in this study are responsible for the inhibitory activity. Our results demonstrate that multiple antibiotic-resistant bacteria associated with subclinical mastitis in dairy goats from Guanajuato, Mexico, are susceptible to bacteriocins produced by B. thuringiensis.

  17. Bacterial Toxins as Pathogen Weapons Against Phagocytes.

    Science.gov (United States)

    do Vale, Ana; Cabanes, Didier; Sousa, Sandra

    2016-01-01

    Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favor microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signaling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.

  18. Bacterial toxins as pathogen weapons against phagocytes

    Directory of Open Access Journals (Sweden)

    Ana edo Vale

    2016-02-01

    Full Text Available Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favour microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signalling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.

  19. How to Fight Back Against Antibiotic Resistance

    DEFF Research Database (Denmark)

    Dantas, Gautam; Sommer, Morten

    2014-01-01

    Mapping the exchange of genes between pathogens and nonpathogens offers new ways to understand and manage the spread of drug-resistant strains. In reality, the development of new antibiotics is only part of the solution, as pathogens will inevitably develop resistance to even the most promising new...... compounds. To save the era of antibiotics, scientists must figure out what it is about bacterial pathogens that makes resistance inevitable. Although most studies on drug resistance have focused on disease causing pathogens, recent efforts have shifted attention to the resistomes of nonpathogenic bacteria...

  20. Russian vaccines against especially dangerous bacterial pathogens

    Science.gov (United States)

    Feodorova, Valentina A; Sayapina, Lidiya V; Corbel, Michael J; Motin, Vladimir L

    2014-01-01

    In response to the epidemiological situation, live attenuated or killed vaccines against anthrax, brucellosis, cholera, glanders, plague and tularemia were developed and used for immunization of at-risk populations in the Former Soviet Union. Certain of these vaccines have been updated and currently they are used on a selective basis, mainly for high risk occupations, in the Russian Federation. Except for anthrax and cholera these vaccines currently are the only licensed products available for protection against the most dangerous bacterial pathogens. Development of improved formulations and new products is ongoing. PMID:26038506

  1. Deciphering the role of coumarin as a novel quorum sensing inhibitor suppressing virulence phenotypes in bacterial pathogens.

    Science.gov (United States)

    Gutiérrez-Barranquero, José A; Reen, F Jerry; McCarthy, Ronan R; O'Gara, Fergal

    2015-04-01

    The rapid unchecked rise in antibiotic resistance over the last few decades has led to an increased focus on the need for alternative therapeutic strategies for the treatment and clinical management of microbial infections. In particular, small molecules that can suppress microbial virulence systems independent of any impact on growth are receiving increased attention. Quorum sensing (QS) is a cell-to-cell signalling communication system that controls the virulence behaviour of a broad spectrum of bacterial pathogens. QS systems have been proposed as an effective target, particularly as they control biofilm formation in pathogens, a key driver of antibiotic ineffectiveness. In this study, we identified coumarin, a natural plant phenolic compound, as a novel QS inhibitor, with potent anti-virulence activity in a broad spectrum of pathogens. Using a range of biosensor systems, coumarin was active against short, medium and long chain N-acyl-homoserine lactones, independent of any effect on growth. To determine if this suppression was linked to anti-virulence activity, key virulence systems were studied in the nosocomial pathogen Pseudomonas aeruginosa. Consistent with suppression of QS, coumarin inhibited biofilm, the production of phenazines and swarming motility in this organism potentially linked to reduced expression of the rhlI and pqsA quorum sensing genes. Furthermore, coumarin significantly inhibited biofilm formation and protease activity in other bacterial pathogens and inhibited bioluminescence in Aliivibrio fischeri. In light of these findings, coumarin would appear to have potential as a novel quorum sensing inhibitor with a broad spectrum of action.

  2. Functional characterization of the antibiotic resistance reservoir in the human microflora

    DEFF Research Database (Denmark)

    Sommer, Morten; Church, George M; Dantas, Gautam

    2010-01-01

    The increasing levels of multi-drug resistance in human pathogenic bacteria are compromising our ability to treat infectious disease. Since antibiotic resistance determinants are readily exchanged between bacteria through lateral gene transfer, there is an increasing interest in investigating...... reservoirs of antibiotic resistance accessible to pathogens. Due to the high likelihood of contact and genetic exchange with pathogens during disease progression, the human microflora warrants special attention as perhaps the most accessible reservoir of resistance genes. Indeed, numerous previous studies...... have demonstrated substantial antibiotic resistance in cultured isolates from the human microflora. By applying metagenomic functional selections, we recently demonstrated that the functional repertoire of resistance genes in the human microbiome is much more diverse than suggested using previous...

  3. Distribution and antibiotic resistance of pathogens isolated from inpatients with urinary tract infections%住院患者尿路感染病原菌分布及耐药性监测

    Institute of Scientific and Technical Information of China (English)

    郭远瑜; 雷和月; 陈琴琴; 张国祥

    2012-01-01

    Objective To investigate the distribution and antibiotic resistance of pathogens isolated from inpatients with urinary tract infections.Methods A retrospective analysis was carried out on 1033 strains of pathogens isolated from urine culture in patients with urinary tract infections in Zhejiang Xiaoshan Hospital during January 2009 and December 2011.Urine specimens were cultured with Uricult,and K-B method was used for drug susceptibility test,WHONET 5.6 software was used to analyse drug susceptibility test.Results Among 1033 strains of pathogens,681 (65.9%) were gram-negative bacteria,197 (19.1%) were gram-positive bacteria,and 155 (15.0%) were fungi.The three most prevalent bacteria were Escherichia coli (402 strains,38.9%),Klebsiella pneumoniae (74 strains,7.2%) and Candida albicans (64 strains,6.2%).60.7% (244/402) of Escherichia coli and 45.9% (34/74) of Klebsiella pneumoniae were extended-spectrum β-lactamases (ESBLs) positive.Escherichia coli and Klebsiella pneumoniae were susceptible to imipenem,meropenem,cefoperazone/sulbactam,piperacillin/tazobactam and amikacin.Enterococcus and staphylococcus were susceptible to vancomycin,linezolid and furadantin.Candida was sensitive to flucytosine,voriconazole and amphotericin B.Conclusion Gram-negative bacteria mainly E.coli is the predominant pathogen to urinary tract infections in this group of patients.Regular analysis and monitoring of pathogen species and drug resistance is important for rational use of antibiotics.%目的 通过调查和分析住院患者尿路感染病原菌的分布及耐药状况,为抗菌药物的合理应用提供参考.方法 对浙江萧山医院2009年1月-2011年12月住院患者尿培养阳性样本中分离的1033株菌株进行回顾性分析,尿液采用经典型浸片Uricult培养,药敏试验用K-B法进行,采用WHONET 5.6软件对药敏试验结果进行分析.结果 1033株阳性菌株中,革兰阴性菌681株(65.9%),革兰阳性菌197株(19.1%),真菌155

  4. Origins and evolution of antibiotic resistance.

    Science.gov (United States)

    Davies, Julian; Davies, Dorothy

    2010-09-01

    Antibiotics have always been considered one of the wonder discoveries of the 20th century. This is true, but the real wonder is the rise of antibiotic resistance in hospitals, communities, and the environment concomitant with their use. The extraordinary genetic capacities of microbes have benefitted from man's overuse of antibiotics to exploit every source of resistance genes and every means of horizontal gene transmission to develop multiple mechanisms of resistance for each and every antibiotic introduced into practice clinically, agriculturally, or otherwise. This review presents the salient aspects of antibiotic resistance development over the past half-century, with the oft-restated conclusion that it is time to act. To achieve complete restitution of therapeutic applications of antibiotics, there is a need for more information on the role of environmental microbiomes in the rise of antibiotic resistance. In particular, creative approaches to the discovery of novel antibiotics and their expedited and controlled introduction to therapy are obligatory.

  5. Antibiotic resistance genes in the environment

    Directory of Open Access Journals (Sweden)

    Jianqiang Su

    2013-07-01

    Full Text Available Antibiotic resistance and its spread in bacteria are topics of great importance in global research. In this paper, we review recent progress in understanding sources, dissemination, distribution and discovery of novel antibiotics resistance genes (ARGs in the environment. Bacteria exhibiting intrinsic resistance and antibiotic resistant bacteria in feces from humans and animals are the major sources of ARGs occurring in the environment. A variety of novel ARGs have been discovered using functional metagenomics. Recently, the long-term overuse of antibotics in drug therapy and animal husbandry has led to an increase in diversity and abundance of ARGs, causing the environmental dissemination of ARGs in aquatic water, sewage treatmentplants, rivers, sediment and soil. Future research should focus on dissemination mechanisms of ARGs, the discovery of novel ARGs and their resistant mechanisms, and the establishment of environmental risk assessment systems for ARGs.

  6. Water Microbiology. Bacterial Pathogens and Water

    Directory of Open Access Journals (Sweden)

    João P. S. Cabral

    2010-10-01

    Full Text Available Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers. Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  7. Water microbiology. Bacterial pathogens and water.

    Science.gov (United States)

    Cabral, João P S

    2010-10-01

    Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water-cholera, typhoid fever and bacillary dysentery-is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  8. Economic implications of antibiotic resistance in a global economy.

    Science.gov (United States)

    Rudholm, Niklas

    2002-11-01

    This paper concerns the economic implications of antibiotic resistance in a global economy. The global economy consists of several countries, where antibiotic consumption creates a stock of bacteria which is resistant to antibiotics. This stock affects the welfare in all countries because of the risk that resistant bacterial strains may be transmitted. The main purpose of the paper is to compare the socially optimal resource allocation with the allocation brought forward by the decentralized market economy. In addition, a dynamic Pigouvian tax designed to implement the globally optimal resource allocation is presented.

  9. 脑性瘫痪儿童医院获得性肺炎的病原菌分布及耐药性分析%Pathological bacterial distribution and antibiotic resistance of hospital acquired pneumonia in children with cerebral palsy

    Institute of Scientific and Technical Information of China (English)

    刘常青; 左满凤; 钟新; 杨恩华; 朱木良; 高翠姣

    2016-01-01

    目的:了解脑性瘫痪(简称脑瘫)儿童医院获得性肺炎( HAP)的病原菌分布及耐药情况。方法收集2012年1月至2015年5月在本院儿童康复科住院期间感染肺炎的脑瘫患儿402例。结果402份痰标本中共分离到菌株291株,检出率72.4%,其中革兰阴性菌259株(89.0%),革兰阳性菌26株(8.9%),真菌6株(2.1%)。革兰阴性菌主要为大肠埃希菌(32.6%)、肺炎克雷伯菌(24.4%)和铜绿假单胞菌(14.4%),其中大肠埃希菌和肺炎克雷伯菌主要产超广谱β内酰胺酶( ESBLs,产酶率分别为58.9%、59.2%),产ESBLs菌的平均耐药率为55.5%,对碳青霉烯类抗生素的平均耐药率为5.0%。铜绿假单胞菌的平均耐药率34.9%,对碳青霉烯类抗生素均敏感。结论脑瘫儿童HAP的病原菌以革兰阴性菌“大肠埃希菌、肺炎克雷伯菌”为主,两者产ESBLs 菌检出率达58%以上,平均耐药率为55.5%,可指导临床首次经验性选药,以提高脑瘫儿童HAP的治疗有效率。%Objective To investigate the pathological bacterial distribution and their antibiotic resistance of hospital acquired pneumonia in children with cerebral palsy. Methods Induced sputum was extracted from 402 ca-ses of hospitalized children with cerebral palsy infected hospital acquired pneumonia in children rehabilitation depart-ment from January 2012 to May 2015. Results A total of 291 (72. 4%) strains of bacteria were isolated from in-duced sputum in the 402 children. The Gram-negative strains were detected in 259 strains (89. 0%), and the Gram-positive strains were found in 26 strains ( 8. 9%) in 291 strains. The others were fungal strains ( 6 strains, 2. 1%) . The Gram-negative bacteria included Escherichia coli ( 32. 6%) , Klebsiella pneumoniae ( 24. 4%) , and Pseudomonas aeruginosa (14. 4%). Escherichia coli and Klebsiella pneumoniae could produce extended-spectrumβ-lactamases ( ESBLs) ( The rates of enzyme production were 58. 9% and 59. 2%) . The

  10. Chemical Countermeasures for Antibiotic Resistance

    Science.gov (United States)

    2015-01-01

    library for suppression of MRSA resistance to penicillin G and oxacillin. Synthetic methodologies to access seven scaffolds (Figure 2)3-8 based...Infective Agents, Accepted Bacterial biofilms are defined as a surface attached community of bacteria embedded in a matrix of extracellular polymeric ...a surface attached community of bacteria embedded in a matrix of extracellular polymeric substances that they have produced. When in the biofilm

  11. The survey of shigellosis frequency and determination of antibiotic resistance profile of isolated strains from infected children in Tehran

    Directory of Open Access Journals (Sweden)

    Shahla Abbaspour

    2014-04-01

    Full Text Available Background: Shigellosis is endemic throughout the world and it is among the most common causes of bacterial diarrheal diseases. Antibiotic resistance of Shigella is becoming a progressive problem in world. The aim of this study was the survey of shigellosis frequency and determination of antibiotic resistance profile of isolated strains from infected children in Tehran. Material and Methods: This study conducted on 9131 patients with acute diarrheal disease. For isolation of Shigella spp. from stool samples, culture performed on different selective and differential media. After confirmation of bacteria by biochemical tests, susceptibility testing was done by disc diffusion method according to clinical and laboratory standards (CLSI recomendations. Results: Among 9131 stool samples, Shigella spp. was isolated from 90 cases. Shigella sonnei was the most common isolated species. 92/2 % of isolates were resistant to cotrimoxazole. In contrast, most of the Shigella spp. was founded to be sensitive to ciprofloxacin, imipenem and third-generation cephalosporins. Conclusion: Surveillance programs on antimicrobial resistance not only identify pathogenic bacterial species, by reporting data like serotyping, microorganisms incidence rates, and susceptibility to the antimicrobial agents currently used for treatment, but also contribute to monitoring the intervention strategies including removing organism from reservoirs.

  12. Shellfish as reservoirs of bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Harry Hariharan

    2016-04-01

    Full Text Available The objective of this article is to present an overview on bacterial pathogens associated with shellfish in Grenada and other countries including the authors’ experience. Although there have been considerable published work on vibrios, there is a lack of information on Salmonella serovars associated with various shellfish. In Grenada, for instance the blue land crabs collected from their habitats were found to harbor several Salmonella serovars. Also, it is notable that only minimal research has been done on shellfish such as conchs and whelks, which are common in the Caribbean and West Indies. Information on anaerobic bacteria, particularly, non-spore forming bacteria associated with shellfish, in general, is also scanty. This review re-examines this globally important topic based on the recent findings as well as past observations. Strategies for reduction of bacteria in oysters are briefly mentioned because of the fact that oysters are consumed commonly without complete cooking.

  13. Shellifsh as reservoirs of bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Harry Hariharan; Victor Amadi

    2016-01-01

    The objective of this article is to present an overview on bacterial pathogens associated with shellfish in Grenada and other countries including the authors’ experience. Although there have been considerable published work on vibrios, there is a lack of information on Salmonellaserovars associated with various shellfish. In Grenada, for instance the blue land crabs collected from their habitats were found to harbor severalSalmonellaserovars. Also, it is notable that only minimal research has been done on shellfish such as conchs and whelks, which are common in the Caribbean and West Indies. Information on anaerobic bacteria, particularly, non-spore forming bacteria associated with shellfish, in general, is also scanty. This review re-examines this globally important topic based on the recent findings as well as past observations. Strategies for reduction of bacteria in oysters are briefly mentioned because of the fact that oysters are consumed commonly without complete cooking.

  14. Acquired antibiotic resistance genes:an overview

    NARCIS (Netherlands)

    Hoek, A.H. van; Mevius, D.; Guerra, B.; Mullany, P.; Robberts, A.P.

    2011-01-01

    In this review an overview is given on antibiotic resistance (AR) mechanisms with special attentions to the AR genes described so far preceded by a short introduction on the discovery and mode of action of the different classes of antibiotics. As this review is only dealing with acquired resistance,

  15. Acquired antibiotic resistance genes: an overview

    NARCIS (Netherlands)

    Hoek, van A.H.; Mevius, D.J.; Guerra, B.; Mullany, P.; Roberts, A.P.; Aarts, H.J.

    2011-01-01

    In this review an overview is given on antibiotic resistance (AR) mechanisms with special attentions to the AR genes described so far preceded by a short introduction on the discovery and mode of action of the different classes of antibiotics. As this review is only dealing with acquired resistance,

  16. Antibiotic resistance: a physicist’s view

    Science.gov (United States)

    Allen, Rosalind; Waclaw, Bartłomiej

    2016-08-01

    The problem of antibiotic resistance poses challenges across many disciplines. One such challenge is to understand the fundamental science of how antibiotics work, and how resistance to them can emerge. This is an area where physicists can make important contributions. Here, we highlight cases where this is already happening, and suggest directions for further physics involvement in antimicrobial research.

  17. Selective decontamination and antibiotic resistance in ICUs

    NARCIS (Netherlands)

    Plantinga, Nienke L.; Bonten, Marc J. M.

    2015-01-01

    Selective digestive decontamination (SDD) and selective oropharyngeal decontamination (SOD) have been associated with reduced mortality and lower ICU-acquired bacteremia and ventilator-associated pneumonia rates in areas with low levels of antibiotic resistance. However, the effect of selective deco

  18. Influence of population density on antibiotic resistance

    NARCIS (Netherlands)

    Bruinsma, N; Hutchinson, JM; van den Bogaard, AE; Giamarellou, H; Degener, J; Stobberingh, EE

    2003-01-01

    Antibiotic consumption and population density as a measure of crowding in the community were related to the prevalence of antibiotic resistance of three cities in three different countries: St Johns in Newfoundland (Canada), Athens in Greece and Groningen in The Netherlands. Antibiotic consumption w

  19. Molecular structure and translocation of a multiple antibiotic resistance region of a Psychrobacter psychrophilus permafrost strain.

    Science.gov (United States)

    Petrova, Mayya; Gorlenko, Zhosephine; Mindlin, Sofia

    2009-06-01

    A Psychrobacter psychrophilus strain resistant to tetracycline and streptomycin was isolated from a 15,000-35,000-year-old permafrost subsoil sediment sampled from the coast of the Eastern-Siberian Sea. The genes conferring antibiotic resistance were localized on an c. 30-kb pKLH80 plasmid. It was shown that the antibiotic resistance region of this plasmid has a mosaic structure and contains closely linked streptomycin resistance (strA-strB) and tetracycline resistance [tetR-tet(H)] genes, followed by a novel IS element (ISPpy1) belonging to the IS3 family. Both the strA-strB and tetR-tet(H) genes of pKLH80 were highly similar to those found in modern clinical bacterial isolates. It was shown that the ISPpy1 element of pKLH80 can direct translocation of the adjacent antibiotic resistance genes to different target plasmids, either by one-ended transposition or by formation of a composite transposon resulting from the insertion of the ISPpy1 second copy at the other side of the antibiotic resistance region. Thus, our data demonstrate that clinically important antibiotic resistance genes originated long before the introduction of antibiotics into clinical practice and confirm an important role of horizontal gene transfer in the distribution of these genes in natural bacterial populations.

  20. Antibiotic resistance in bacteria from shrimp farming in mangrove areas.

    Science.gov (United States)

    Le, Tuan Xuan; Munekage, Yukihiro; Kato, Shin-ichiro

    2005-10-15

    Shrimp farming is a sufficiently large and mature industry to have an effective range of antimicrobial agents for most bacterial diseases in shrimp culture. However, at present, there exists great concern over the widespread use of antibiotics in aquaculture, which may result in residue of antibiotics in water and mud, and subsequently, the development of antibiotic resistance in bacteria in the environment. There is limited understanding about the effect of antibiotic residues on bacteria resistance in shrimp farming environment. Therefore, a study was conducted to investigate bacterial resistance to Norfloxacin (NFXC), Oxolinic Acid (OXLA), Trimethoprim (TMP) and Sulfamethoxazole (SMX), which were found in four shrimp farming locations in mangrove areas in Vietnam. Findings indicate that there is a relatively high incidence of bacteria resistance to these antibiotics observed in most of the studied sites, particularly to antibiotics with concentration of 0.1 microg/ml. Yet the relation between concentration of antibiotic residues and incidence of antibiotic resistance is not clearly defined. Among individual antibiotics, the incidence of resistance to TMP and SMX was higher than the others. Identification of bacteria isolated from mud samples by DNA analyzer shows that Bacillus and Vibrio are predominant among bacteria resistant to the antibiotics. The result of the study also indicates that these antibiotics in media degraded more rapidly due to the presence of resistant bacteria.

  1. Antibiotic-Resistant Bacteria Detected in Sewage Spill

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_160031.html Antibiotic-Resistant Bacteria Detected in Sewage Spill 'People need to be ... News) -- Sewer line breaks can release antibiotic-resistant bacteria that pose a public health threat, a new ...

  2. Peptidomimetic Small Molecules Disrupt Type IV Secretion System Activity in Diverse Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Carrie L. Shaffer

    2016-04-01

    Full Text Available Bacteria utilize complex type IV secretion systems (T4SSs to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85 that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA and peptidoglycan into gastric epithelial cells. In H. pylori, KSK85 impedes biogenesis of the pilus appendage associated with the cag T4SS, while C10 disrupts cag T4SS activity without perturbing pilus assembly. In addition to the effects in H. pylori, we demonstrate that these compounds disrupt interbacterial DNA transfer by conjugative T4SSs in Escherichia coli and impede vir T4SS-mediated DNA delivery by Agrobacterium tumefaciens in a plant model of infection. Of note, C10 effectively disarmed dissemination of a derepressed IncF plasmid into a recipient bacterial population, thus demonstrating the potential of these compounds in mitigating the spread of antibiotic resistance determinants driven by conjugation. To our knowledge, this study is the first report of synthetic small molecules that impair delivery of both effector protein and DNA cargos by diverse T4SSs.

  3. The role of aquatic ecosystems as reservoirs of antibiotic resistance.

    Science.gov (United States)

    Marti, Elisabet; Variatza, Eleni; Balcazar, Jose Luis

    2014-01-01

    Although antibiotic resistance has become a major threat to human health worldwide, this phenomenon has been largely overlooked in studies in environmental settings. Aquatic environments may provide an ideal setting for the acquisition and dissemination of antibiotic resistance, because they are frequently impacted by anthropogenic activities. This review focuses primarily on the emergence and dissemination of antibiotic resistance in the aquatic environment, with a special emphasis on the role of antibiotic resistance genes.

  4. Low Temperature and Modified Atmosphere: Hurdles for Antibiotic Resistance Transfer?

    Science.gov (United States)

    Van Meervenne, Eva; Van Coillie, Els; Van Weyenberg, Stephanie; Boon, Nico; Herman, Lieve; Devlieghere, Frank

    2015-12-01

    Food is an important dissemination route for antibiotic-resistant bacteria. Factors used during food production and preservation may contribute to the transfer of antibiotic resistance genes, but research on this subject is scarce. In this study, the effect of temperature (7 to 37°C) and modified atmosphere packaging (air, 50% CO2-50% N2, and 100% N2) on antibiotic resistance transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes was evaluated. Filter mating was performed on nonselective agar plates with high-density inocula. A more realistic setup was created by performing modified atmosphere experiments on cooked ham using high-density and low-density inocula. Plasmid transfer was observed between 10 and 37°C, with plasmid transfer also observed at 7°C during a prolonged incubation period. When high-density inocula were used, transconjugants were detected, both on agar plates and cooked ham, under the three atmospheres (air, 50% CO2-50% N2, and 100% N2) at 7°C. This yielded a median transfer ratio (number of transconjugants/number of recipients) with an order of magnitude of 10(-4) to 10(-6). With low-density inocula, transfer was only detected under the 100% N2 atmosphere after 10-day incubation at 7°C, yielding a transfer ratio of 10(-5). Under this condition, the highest bacterial density was obtained. The results indicate that low temperature and modified atmosphere packaging, two important hurdles in the food industry, do not necessarily prevent plasmid transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes.

  5. Plasmid metagenomics reveals multiple antibiotic resistance gene classes among the gut microbiomes of hospitalised patients.

    Science.gov (United States)

    Jitwasinkul, Tossawan; Suriyaphol, Prapat; Tangphatsornruang, Sithichoke; Hansen, Martin Asser; Hansen, Lars Hestbjerg; Sørensen, Søren Johannes; Permpikul, Chairat; Rongrungruang, Yong; Tribuddharat, Chanwit

    2016-09-01

    Antibiotic resistance genes are rapidly spread between pathogens and the normal flora, with plasmids playing an important role in their circulation. This study aimed to investigate antibiotic resistance plasmids in the gut microbiome of hospitalised patients. Stool samples were collected from seven inpatients at Siriraj Hospital (Bangkok, Thailand) and were compared with a sample from a healthy volunteer. Plasmids from the gut microbiomes extracted from the stool samples were subjected to high-throughput DNA sequencing (GS Junior). Newbler-assembled DNA reads were categorised into known and unknown sequences (using >80% alignment length as the cut-off), and ResFinder was used to classify the antibiotic resistance gene pools. Plasmid replicon modules were used for plasmid typing. Forty-six genes conferring resistance to several classes of antibiotics were identified in the stool samples. Several antibiotic resistance genes were shared by the patients; interestingly, most were reported previously in food animals and healthy humans. Four antibiotic resistance genes were found in the healthy subject. One gene (aph3-III) was identified in the patients and the healthy subject and was related to that in cattle. Uncommon genes of hospital origin such as blaTEM-124-like and fosA, which confer resistance to extended-spectrum β-lactams and fosfomycin, respectively, were identified. The resistance genes did not match the patients' drug treatments. In conclusion, several plasmid types were identified in the gut microbiome; however, it was difficult to link these to the antibiotic resistance genes identified. That the antibiotic resistance genes came from hospital and community environments is worrying.

  6. Enteric bacterial pathogens in children with diarrhea in Niger: diversity and antimicrobial resistance.

    Directory of Open Access Journals (Sweden)

    Céline Langendorf

    Full Text Available Although rotavirus is the leading cause of severe diarrhea among children in sub-Saharan Africa, better knowledge of circulating enteric pathogenic bacteria and their antimicrobial resistance is crucial for prevention and treatment strategies.As a part of rotavirus gastroenteritis surveillance in Maradi, Niger, we performed stool culture on a sub-population of children under 5 with moderate-to-severe diarrhea between April 2010 and March 2012. Campylobacter, Shigella and Salmonella were sought with conventional culture and biochemical methods. Shigella and Salmonella were serotyped by slide agglutination. Enteropathogenic Escherichia coli (EPEC were screened by slide agglutination with EPEC O-typing antisera and confirmed by detection of virulence genes. Antimicrobial susceptibility was determined by disk diffusion. We enrolled 4020 children, including 230 with bloody diarrhea. At least one pathogenic bacterium was found in 28.0% of children with watery diarrhea and 42.2% with bloody diarrhea. Mixed infections were found in 10.3% of children. EPEC, Salmonella and Campylobacter spp. were similarly frequent in children with watery diarrhea (11.1%, 9.2% and 11.4% respectively and Shigella spp. were the most frequent among children with bloody diarrhea (22.1%. The most frequent Shigella serogroup was S. flexneri (69/122, 56.5%. The most frequent Salmonella serotypes were Typhimurimum (71/355, 20.0%, Enteritidis (56/355, 15.8% and Corvallis (46/355, 13.0%. The majority of putative EPEC isolates was confirmed to be EPEC (90/111, 81.1%. More than half of all Enterobacteriaceae were resistant to amoxicillin and co-trimoxazole. Around 13% (46/360 Salmonella exhibited an extended-spectrum beta-lactamase phenotype.This study provides updated information on enteric bacteria diversity and antibiotic resistance in the Sahel region, where such data are scarce. Whether they are or not the causative agent of diarrhea, bacterial infections and their antibiotic

  7. Evolution of Bacterial Pathogens within the Human Host

    OpenAIRE

    Bliven, Kimberly A.; Maurelli, Anthony T.

    2016-01-01

    Selective pressures within the human host, including interactions with innate and adaptive immune responses, exposure to medical interventions such as antibiotics, and competition with commensal microbiota all facilitate the evolution of bacterial pathogens. In this chapter, we present examples of pathogen strategies which emerged as a result of selective pressures within the human host niche, and discuss the resulting co-evolutionary ‘arms race’ between these organisms. In bacterial pathogen...

  8. Differential epigenetic compatibility of qnr antibiotic resistance determinants with the chromosome of Escherichia coli.

    Directory of Open Access Journals (Sweden)

    María B Sánchez

    Full Text Available Environmental bacteria harbor a plethora of genes that, upon their horizontal transfer to new hosts, may confer resistance to antibiotics, although the number of such determinants actually acquired by pathogenic bacteria is very low. The founder effect, fitness costs and ecological connectivity all influence the chances of resistance transfer being successful. We examined the importance of these bottlenecks using the family of quinolone resistance determinants Qnr. The results indicate the epigenetic compatibility of a determinant with the host genome to be of great importance in the acquisition and spread of resistance. A plasmid carrying the widely distributed QnrA determinant was stable in Escherichia coli, whereas the SmQnr determinant was unstable despite both proteins having very similar tertiary structures. This indicates that the fitness costs associated with the acquisition of antibiotic resistance may not derive from a non-specific metabolic burden, but from the acquired gene causing specific changes in bacterial metabolic and regulatory networks. The observed stabilization of the plasmid encoding SmQnr by chromosomal mutations, including a mutant lacking the global regulator H-NS, reinforces this idea. Since quinolones are synthetic antibiotics, and since the origin of QnrA is the environmental bacterium Shewanella algae, the role of QnrA in this organism is unlikely to be that of conferring resistance. Its evolution toward this may have occurred through mutations or because of an environmental change (exaptation. The present results indicate that the chromosomally encoded Qnr determinants of S. algae can confer quinolone resistance upon their transfer to E. coli without the need of any further mutation. These results suggest that exaptation is important in the evolution of antibiotic resistance.

  9. Antibiotic resistance in bacteria isolated from vegetables with regards to the marketing stage (farm vs. supermarket).

    Science.gov (United States)

    Schwaiger, Karin; Helmke, Katharina; Hölzel, Christina Susanne; Bauer, Johann

    2011-08-15

    The aim of this study was to elucidate whether and to what extent fresh produce from Germany plays a role as a carrier and reservoir of antibiotic resistant bacteria. For this purpose, 1001 vegetables (fruit, root, bulbous vegetables, salads and cereals) were collected from 13 farms and 11 supermarkets in Germany and examined bacteriologically. Phenotypic resistance of Enterobacter cloacae (n=172); Enterobacter gergoviae (n=92); Pantoea agglomerans (n=96); Pseudomonas aeruginosa (n=295); Pseudomonas putida (n=106) and Enterococcus faecalis (n=100) against up to 30 antibiotics was determined by using the microdilution method. Resistance to ß-lactams was most frequently expressed by P. agglomerans and E. gergoviae against cefaclor (41% and 29%). Relatively high resistance rates were also observed for doxycycline (23%), erythromycin (21%) and rifampicin (65%) in E. faecalis, for spectinomycin (28%) and mezlocillin (12%) in E. cloacae, as well as for streptomycin (19%) in P. putida. In P. aeruginosa, relatively low resistance rates were observed for the aminoglycosides amikacin, apramicin, gentamicin, neomycin, netilmicin and tobramycin (4%); 11% was resistant to streptomycin. No glycopeptide-resistant enterococci were observed. Resistance rates of bacteria isolated from farm samples were higher than those of the retail markets whenever significant differences were observed. This suggests that expressing resistance is at the expense of bacterial viability, since vegetables purchased directly at the farm are probably fresher than at the supermarket, and they have not been exposed to stress factors. However, this should not keep the customer from buying directly at the farm, since the overall resistance rates were not higher than observed in bacteria from human or animal origin. Instead, peeling or washing vegetables before eating them raw is highly recommended, since it reduces not only the risk of contact with pathogens, but also that of ingesting and spreading

  10. Bacteriophage selection against a plasmid-encoded sex apparatus leads to the loss of antibiotic-resistance plasmids

    OpenAIRE

    Jalasvuori, Matti; Friman, Ville-Petri; Nieminen, Anne; Jaana K.H. Bamford; Buckling, Angus

    2011-01-01

    Antibiotic-resistance genes are often carried by conjugative plasmids, which spread within and between bacterial species. It has long been recognized that some viruses of bacteria (bacteriophage; phage) have evolved to infect and kill plasmid-harbouring cells. This raises a question: can phages cause the loss of plasmid-associated antibiotic resistance by selecting for plasmid-free bacteria, or can bacteria or plasmids evolve resistance to phages in other ways? Here, we show that multiple ant...

  11. Molecular methods for assessment of antibiotic resistance in agricultural ecosystems: prospects and challenges

    Science.gov (United States)

    Agricultural ecosystems are of special interest for monitoring the potential for antibiotic resistance to spread through the environment and contribute to human exposure. Molecular methods, which target DNA, RNA, and other molecular components of bacterial cells, present certain advantages for char...

  12. Occurrence and movement of antibiotic resistant bacxteria, in tile-drained agricultural fields receiving swine manure

    Science.gov (United States)

    The use of tylosin at subtherapeutic levels by the swine industry provides selective pressure for the development of antibiotic resistance in gastrointestinal bacteria. The land application of swine manure to drained agricultural fields might accelerate the transport of pathogen indicators such as e...

  13. A systematic review and meta-analysis of the effects of antibiotic consumption on antibiotic resistance.

    NARCIS (Netherlands)

    Bell, B.G.; Schellevis, F.; Stobberingh, E.; Goossen, H.; Pringle, M.

    2014-01-01

    Background: Greater use of antibiotics during the past 50 years has exerted selective pressure on susceptible bacteria and may have favoured the survival of resistant strains. Existing information on antibiotic resistance patterns from pathogens circulating among community-based patients is substant

  14. Antibiotic resistance: an editorial review with recommendations.

    Science.gov (United States)

    Rosen, Ted

    2011-07-01

    Within a relatively short period of time after the first antimicrobial drugs were introduced, bacteria began exhibiting varying degrees of resistance. The excessive use (and abuse) of antibiotics in agriculture, and in both human and veterinary medicine, has played a critical causative role in the development of antibiotic resistance, which is now recognized as a global public health threat. Increasing concern over this issue should impact the practice of cutaneous medicine and surgery, as dermatologists can easily adopt new healthcare delivery patterns that might reduce the development of antibiotic resistance and still achieve acceptable treatment outcomes. Dermatologists should seriously consider any and all alternative therapies before committing to an extended course of antibiotic therapy for disease entities that are almost certainly not infectious. Conversely, dermatologists should carefully and closely adhere to dosage and duration recommendations when using antibiotics to treat a bona fide infectious disorder.

  15. The transfer of antibiotic resistance from food to humans: facts, implications and future directions.

    Science.gov (United States)

    Wang, H; McEntire, J C; Zhang, L; Li, X; Doyle, M

    2012-04-01

    The food chain, from production to the consumer's kitchen, can be an important contributor to the development, persistence and dissemination of antibiotic-resistant (ART) microbes, including both ART foodborne pathogens and commensal bacteria. Many factors in the food chain, such as the antimicrobial compounds used and how they were used, microbial co-selection, fitness and persistence mechanisms, host lifestyle, and food treatment conditions, influence the antibiotic resistance (AR) cycle. Targeted mitigation strategies, such as those used in the dairy processing industry, can be effective in reducing the AR gene pool.

  16. Antibiotic resistance genes detected in the marine sponge Petromica citrina from Brazilian coast

    Directory of Open Access Journals (Sweden)

    Marinella Silva Laport

    Full Text Available ABSTRACT Although antibiotic-resistant pathogens pose a significant threat to human health, the environmental reservoirs of the resistance determinants are still poorly understood. This study reports the detection of resistance genes (ermB, mecA, mupA, qnrA, qnrB and tetL to antibiotics among certain culturable and unculturable bacteria associated with the marine sponge Petromica citrina. The antimicrobial activities elicited by P. citrina and its associated bacteria are also described. The results indicate that the marine environment could play an important role in the development of antibiotic resistance and the dissemination of resistance genes among bacteria.

  17. Antimicrobial susceptibility testing for Helicobacter pylori in times of increasing antibiotic resistance.

    Science.gov (United States)

    Smith, Sinéad M; O'Morain, Colm; McNamara, Deirdre

    2014-08-07

    The gram-negative bacterium Helicobacter pylori (H. pylori) causes chronic gastritis, gastric and duodenal ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Treatment is recommended in all symptomatic patients. The current treatment options for H. pylori infection are outlined in this review in light of the recent challenges in eradication success, largely due to the rapid emergence of antibiotic resistant strains of H. pylori. Antibiotic resistance is a constantly evolving process and numerous studies have shown that the prevalence of H. pylori antibiotic resistance varies significantly from country to country, and even between regions within the same country. In addition, recent data has shown that previous antibiotic use is associated with harbouring antibiotic resistant H. pylori. Local surveillance of antibiotic resistance is warranted to guide clinicians in their choice of therapy. Antimicrobial resistance is assessed by H. pylori culture and antimicrobial susceptibility testing. Recently developed molecular tests offer an attractive alternative to culture and allow for the rapid molecular genetic identification of H. pylori and resistance-associated mutations directly from biopsy samples or bacterial culture material. Accumulating evidence indicates that surveillance of antimicrobial resistance by susceptibility testing is feasible and necessary to inform clinicians in their choice of therapy for management of H. pylori infection.

  18. Influence of Dissolved Organic Matter on Tetracycline Bioavailability to an Antibiotic-Resistant Bacterium.

    Science.gov (United States)

    Chen, Zeyou; Zhang, Yingjie; Gao, Yanzheng; Boyd, Stephen A; Zhu, Dongqiang; Li, Hui

    2015-09-15

    Complexation of tetracycline with dissolved organic matter (DOM) in aqueous solution could alter the bioavailability of tetracycline to bacteria, thereby alleviating selective pressure for development of antibiotic resistance. In this study, an Escherichia coli whole-cell bioreporter construct with antibiotic resistance genes coupled to green fluorescence protein was exposed to tetracycline in the presence of DOM derived from humic acids. Complexation between tetracycline and DOM diminished tetracycline bioavailability to E. coli, as indicated by reduced expression of antibiotic resistance genes. Increasing DOM concentration resulted in decreasing bioavailability of tetracycline to the bioreporter. Freely dissolved tetracycline (not complexed with DOM) was identified as the major fraction responsible for the rate and magnitude of antibiotic resistance genes expressed. Furthermore, adsorption of DOM on bacterial cell surfaces inhibited tetracycline diffusion into the bioreporter cells. The magnitude of the inhibition was related to the amount of DOM adsorbed and tetracycline affinity for the DOM. These findings provide novel insights into the mechanisms by which the bioavailability of tetracycline antibiotics to bacteria is reduced by DOM present in water. Agricultural lands receiving livestock manures commonly have elevated levels of both DOM and antibiotics; the DOM could suppress the bioavailability of antibiotics, hence reducing selective pressure on bacteria for development of antibiotic resistance.

  19. Diversity and antibiotic resistance patterns of Sphingomonadaceae isolates from drinking water.

    Science.gov (United States)

    Vaz-Moreira, Ivone; Nunes, Olga C; Manaia, Célia M

    2011-08-15

    Sphingomonadaceae (n = 86) were isolated from a drinking water treatment plant (n = 6), tap water (n = 55), cup fillers for dental chairs (n = 21), and a water demineralization filter (n = 4). The bacterial isolates were identified based on analysis of the 16S rRNA gene sequence, and intraspecies variation was assessed on the basis of atpD gene sequence analysis. The isolates were identified as members of the genera Sphingomonas (n = 27), Sphingobium (n = 28), Novosphingobium (n = 12), Sphingopyxis (n = 7), and Blastomonas (n = 12). The patterns of susceptibility to five classes of antibiotics were analyzed and compared for the different sites of isolation and taxonomic groups. Colistin resistance was observed to be intrinsic (92%). The highest antibiotic resistance prevalence values were observed in members of the genera Sphingomonas and Sphingobium and for beta-lactams, ciprofloxacin, and cotrimoxazole. In tap water and in water from dental chairs, antibiotic resistance was more prevalent than in the other samples, mainly due to the predominance of isolates of the genera Sphingomonas and Sphingobium. These two genera presented distinct patterns of association with antibiotic resistance, suggesting different paths of resistance development. Antibiotic resistance patterns were often related to the species rather than to the site or strain, suggesting the importance of vertical resistance transmission in these bacteria. This is the first study demonstrating that members of the family Sphingomonadaceae are potential reservoirs of antibiotic resistance in drinking water.

  20. 小儿心脏监护病房病原菌分布及超广谱β-内酰胺酶阳性菌的耐药性分析%Distribution of pathogenic bacteria and antibiotic resistance of ESBLs (+)bacteria in CICU

    Institute of Scientific and Technical Information of China (English)

    王保存; 丁力; 张峰

    2016-01-01

    目的:监测、分析小儿心脏监护病房(CICU)病原菌分布特点及超广谱β-内酰胺酶阳性菌[ESBLs(+)]的耐药状况,为指导临床合理用药提供理论依据。方法回顾性分析 CICU 分离的病原菌及耐药性。结果送检各类标本共计1192份,检测出病原菌124株(10.4%),主要来源于呼吸道(74株,59.7%),其中革兰阴性菌62株(50.0%)、革兰阳性菌50株(40.3%)、真菌12株(9.7%)。ESBLs(+)菌共24株(19.4%),均检自肺炎克雷伯菌及大肠埃希菌,对青霉素类、头孢菌素、氨曲南的耐药率高,对氨基糖苷类、喹诺酮类、碳氢霉烯类的耐药率低。结论CICU 病原菌多来源于呼吸道,ESBLs(+)菌的检出率高、耐药严重,应加强监测病原菌分布及耐药性,指导临床合理应用抗菌药物。%Objective To monitor and analyze the distribution of pathogenic bacteria and antibiotic resistance of ESBLs (+)bacteria in CICU of Anhui Provincial Children’s Hospital,in order to provide the theoretical basis for rational use of antibiotics in clinical prac-tice.Methods A retrospective analysis was made of pathogenic bacteria separated in CICU from January 2011 to December 2015 and of their antibiotic resistance.Results From a total of 1 192 samples,the detected pathogenic bacteria were 124 strains (10.4%), mainly derived from the respiratory tract (74 strains,59.7%).Among them,there were 62 strains (50.0%)of gram-negative bacteria, 50 strains (40.3%)of gram positive bacteria and 12 strains (9.7%)of fungus.ESBLs (+)bacteria,a total of 24 strains (19.4%), were both from pneumonia klebsiella bacteria and e.Coli,which were highly resistant to penicillin,cephalosporin and aztreonam,but were lowly resistant to aminoglycoside,quinolone and hydrocarbon alkene.Conclusions Pathogenic bacteria in CICU were mainly de-rived from respiratory tract.The detection rate of ESBLs (+)bacteria was

  1. Acquired Antibiotic Resistance Genes: An Overview

    OpenAIRE

    Hoek, Angela H.A.M. van; Mevius, Dik; Guerra, Beatriz; Mullany, Peter; Roberts, Adam Paul; Aarts, Henk J. M.

    2011-01-01

    In this review an overview is given on antibiotic resistance (AR) mechanisms with special attentions to the AR genes described so far preceded by a short introduction on the discovery and mode of action of the different classes of antibiotics. As this review is only dealing with acquired resistance, attention is also paid to mobile genetic elements such as plasmids, transposons, and integrons, which are associated with AR genes, and involved in the dispersal of antimicrobial determinants betw...

  2. Role of Old Antibiotics in the Era of Antibiotic Resistance. Highlighted Nitrofurantoin for the Treatment of Lower Urinary Tract Infections

    Directory of Open Access Journals (Sweden)

    Maria Jose Munoz-Davila

    2014-02-01

    Full Text Available Bacterial infections caused by antibiotic-resistant isolates have become a major health problem in recent years, since they are very difficult to treat, leading to an increase in morbidity and mortality. Nitrofurantoin is a broad-spectrum bactericidal antibiotic that, through a complex mode of action which is not completely understood, affects both Gram-negative and Gram-positive bacteria. Nitrofurantoin has been used successfully for a long time for the prophylaxis and treatment of acute lower urinary tract infections in adults, children and pregnant women, but the increased emergence of antibiotic resistance has made nitrofurantoin a suitable candidate for the treatment of infections caused by multidrug-resistant pathogens. Here, we review the mechanism of action, antimicrobial spectrum, pharmacology and safety profile of nitrofurantoin. We also investigate the therapeutic use of nitrofurantoin, including recent data which highlight its role in the management of community urinary tract infection, especially in cases of multidrug-resistant isolates, in which oral active antimicrobials are limited resources nowadays.

  3. Determining of antibiotic resistance profile inStaphylococcus aureus isolates

    Institute of Scientific and Technical Information of China (English)

    Hossein Motamedi; Hadis Mirzabeigi; Tahere Shirali

    2010-01-01

    Objective:To determine the pattern of antibiotic resistance amongStaphylococcus aureus (S. aureus) isolates from clinical specimens and to identify community-acquired methicillin-resistantStaphylococcus aureus(CA-MRSA)in specimens that have been collected from patients referring to one of the hospitals of Ahvaz.Methods:S. aureus isolates from a hospital in Ahvaz were screened for resistance to various antibiotics including methicillin. The susceptibility of the isolates was determined by Kirby-Bauer disc diffusion method. TheMRSA was also treated with ethidium bromide to find the origin of resistance.Results: Among the bacterial isolates, all of 11S. aureus were resistant to methicillin and cefixime,2 were resistant to ciprofloxacine,6 were resistant to tetracycline and the reminder were sensitive or intermediate to other antibiotics. The treated isolates were reminded resistant to methicillin and this suggested that the plasmid was not the origin of resistance in these isolates.Conclusions: These results showed that infection due toMRSA is widespread in Ahvaz and with respect to the spread of vancomycin resistance among MRSA and appearance of overwhelming infections. It is necessary to identify continuously the profile of antibiotic resistance amongS. aureus isolates in other regions and finding appropriate antibiotic for infection control and eradication.

  4. Nosocomial infection and its molecular mechanisms of antibiotic resistance.

    Science.gov (United States)

    Xia, Jufeng; Gao, Jianjun; Tang, Wei

    2016-02-01

    Nosocomial infection is a kind of infection, which is spread in various hospital environments, and leads to many serious diseases (e.g. pneumonia, urinary tract infection, gastroenteritis, and puerperal fever), and causes higher mortality than community-acquired infection. Bacteria are predominant among all the nosocomial infection-associated pathogens, thus a large number of antibiotics, such as aminoglycosides, penicillins, cephalosporins, and carbapenems, are adopted in clinical treatment. However, in recent years antibiotic resistance quickly spreads worldwide and causes a critical threat to public health. The predominant bacteria include Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii. In these bacteria, resistance emerged from antibiotic resistant genes and many of those can be exchanged between bacteria. With technical advances, molecular mechanisms of resistance have been gradually unveiled. In this review, recent advances in knowledge about mechanisms by which (i) bacteria hydrolyze antibiotics (e.g. extended spectrum β-lactamases, (ii) AmpC β-lactamases, carbapenemases), (iii) avoid antibiotic targeting (e.g. mutated vanA and mecA genes), (iv) prevent antibiotic permeation (e.g. porin deficiency), or (v) excrete intracellular antibiotics (e.g. active efflux pump) are summarized.

  5. [3] Diseases Caused By Bacterial Pathogens In Inland Water

    OpenAIRE

    若林, 久嗣; 吉田, 照豊; 野村, 哲一; 中井, 敏博; 高野, 倫一

    2016-01-01

    Bacterial diseases cause huge damages in fish farms worldwide, and numerous bacterial pathogens from inland and saline waters have been identified and studied for their characterization, diagnosis, prevention and control. In this chapter, eight important fish diseases viz. 1) streptococcosis (inland water), 2) furunculosis, 3) bacterial gill disease, 4) columnaris disease, 5) bacterial cold-water disease, 6) red spot disease, 7) edwardsiellosis (Edwardsiella ictaluri), and 8) motile aeromonad...

  6. Evaluation of antimicrobial resistance pattern of nosocomial and community bacterial pathogens at a teaching hospital in Tehran,Iran.

    Directory of Open Access Journals (Sweden)

    Samin Zamani

    2014-03-01

    Full Text Available Antimicrobial resistance in pathogens not only in hospitals but also in the community has become an important public health problem. The aim of this study was to determine the antimicrobial resistance patterns of predominant pathogens from hospitalized and outpatients in a university hospital in Tehran, Iran. A total of 820 samples of common Gram-negative and Gram-positive bacteria were collected from a major referral and teaching hospital affiliated to Tehran University of Medical Sciences in Iran during April 2010 to February 2011. The pattern of antibiotic resistance was determined by disk diffusion test as recommended by the Clinical Laboratory and Standards Institute (CLSI. Gram-negative bacilli were the most isolated pathogens. Acinetobacter spp. and Pseudomonas aeruginosa (P. aeruginosa was the most antibiotic-resistant pathogens. Imipenem and piperacillin/tazobactam were the most active antimicrobials against gram-negative bacilli whereas vancomycin was the antimicrobial agent most consistently active against the Gram-positive cocci. Community-acquired organisms were more susceptible to antimicrobial drugs tested than nosocomial isolates. The rates of antibiotic resistance among isolated pathogens in this study were approximately similar to other studies. However, high rates of antibiotic resistance among Acinetobacter spp and P. aeruginosa, the most isolated pathogens, indicating that antibiotic policy is urgently needed to prevent the resistance development ago.

  7. Evaluation of antimicrobial resistance pattern of nosocomial and community bacterial pathogens at a teaching hospital in Tehran,Iran.

    Science.gov (United States)

    Zamani, Samin; Nasiri, Mohammad Javad; Khoshgnab, Behshad Noorazar; Ashrafi, Abbas; Abdollahi, Alireza

    2014-01-01

    Antimicrobial resistance in pathogens not only in hospitals but also in the community has become an important public health problem. The aim of this study was to determine the antimicrobial resistance patterns of predominant pathogens from hospitalized and outpatients in a university hospital in Tehran, Iran. A total of 820 samples of common Gram-negative and Gram-positive bacteria were collected from a major referral and teaching hospital affiliated to Tehran University of Medical Sciences in Iran during April 2010 to February 2011. The pattern of antibiotic resistance was determined by disk diffusion test as recommended by the Clinical Laboratory and Standards Institute (CLSI). Gram-negative bacilli were the most isolated pathogens. Acinetobacter spp. and Pseudomonas aeruginosa (P. aeruginosa) was the most antibiotic-resistant pathogens. Imipenem and piperacillin/tazobactam were the most active antimicrobials against gram-negative bacilli whereas vancomycin was the antimicrobial agent most consistently active against the Gram-positive cocci. Community-acquired organisms were more susceptible to antimicrobial drugs tested than nosocomial isolates. The rates of antibiotic resistance among isolated pathogens in this study were approximately similar to other studies. However, high rates of antibiotic resistance among Acinetobacter spp and P. aeruginosa, the most isolated pathogens, indicating that antibiotic policy is urgently needed to prevent the resistance development ago.

  8. Antibiotic Susceptibility and Immunomodulatory Potential of Chosen Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    M. Sujatha

    2010-01-01

    Full Text Available Problem statement: Antibiotic susceptibility is still the best way for bacterial pathogen escape mechanism against immunity. Approach: In the present investigation, bacterial pathogens like Staphylococcus aureus, Escherichia coli, Aeromonas hydrophila, Klebsiella and Pseudomonas aeruginosa were used to screen antibiotic susceptibility and immunomodulatory potential. Results: All the test pathogens were sensitive to all the test antibiotics 11±2 mm except penicillin. The conditions for the preparation of antigens of intact natural composition and conformation from pathogens (whole cell and heat killed, were determined using Swiss albino mice (Balb/C as experimental species. Immunomodulatory potential of test pathogens were screened using animal model. Test pathogen decreases the body weight comparing that of normal mice, some notable changes were also noted in activity, growth, water consumption, feed consumption. Antibody titre level in animal serum decreased upto 50% in whole cell pathogen and heat killed pathogen treated animals. Conclusion: The five pathogens administered animals, decrement in B-lymphocyte was much pronounced in Pseudomonas aeruginosa followed by Escherichia coli, Staphylococcus aureus, Klebsiella sp., Aeromonas hydrophila in the 5 week. Pathogen treated mice showed an IgG suppressive effect. It is found to be suppressive to T cell production, so induction in cell mediated immunity has confirmed pathogenic potential of test pathogens. All these test pathogenic strains were remarkably suppressing immune system of pathogen exposed animals.

  9. Evolution of Bacterial Pathogens Within the Human Host.

    Science.gov (United States)

    Bliven, Kimberly A; Maurelli, Anthony T

    2016-02-01

    Selective pressures within the human host, including interactions with innate and adaptive immune responses, exposure to medical interventions such as antibiotics, and competition with commensal microbiota all facilitate the evolution of bacterial pathogens. In this chapter, we present examples of pathogen strategies that emerged as a result of selective pressures within the human host niche and discuss the resulting coevolutionary "arms race" between these organisms. In bacterial pathogens, many of the genes responsible for these strategies are encoded on mobile pathogenicity islands or plasmids, underscoring the importance of horizontal gene transfer in the emergence of virulent microbial species.

  10. Lab on a chip sensor for rapid detection and antibiotic resistance determination of Staphylococcus aureus.

    Science.gov (United States)

    Abeyrathne, Chathurika D; Huynh, Duc H; Mcintire, Thomas W; Nguyen, Thanh C; Nasr, Babak; Zantomio, Daniela; Chana, Gursharan; Abbott, Iain; Choong, Peter; Catton, Mike; Skafidas, Efstratios

    2016-03-21

    The Gram-positive bacterium, Staphylococcus aureus (S. aureus), is a major pathogen responsible for a variety of infectious diseases ranging from cellulitis to more serious conditions such as septic arthritis and septicaemia. Timely treatment with appropriate antibiotic therapy is essential to ensure clinical defervescence and to prevent further complications such as infective endocarditis or organ impairment due to septic shock. To date, initial antibiotic choice is empirical, using a "best guess" of likely organism and sensitivity- an approach adopted due to the lack of rapid identification methods for bacteria. Current culture based methods take up to 5 days to identify the causative bacterial pathogen and its antibiotic sensitivity. This paper provides proof of concept for a biosensor, based on interdigitated electrodes, to detect the presence of S. aureus and ascertain its sensitivity to flucloxacillin rapidly (within 2 hours) in a cost effective manner. The proposed method is label-free and uses non-faradic measurements. This is the first study to successfully employ interdigitated electrodes for the rapid detection of antibiotic resistance. The method described has important potential outcomes of faster definitive antibiotic treatment and more rapid clinical response to treatment.

  11. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    Directory of Open Access Journals (Sweden)

    Dongsheng Che

    2014-01-01

    Full Text Available High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs. PAIs have some detectable properties, such as having different genomic signatures than the rest of the host genomes, and containing mobility genes so that they can be integrated into the host genome. In this review, we will discuss various pathogenicity island-associated features and current computational approaches for the identification of PAIs. Existing pathogenicity island databases and related computational resources will also be discussed, so that researchers may find it to be useful for the studies of bacterial evolution and pathogenicity mechanisms.

  12. Bacteriophage selection against a plasmid-encoded sex apparatus leads to the loss of antibiotic-resistance plasmids.

    Science.gov (United States)

    Jalasvuori, Matti; Friman, Ville-Petri; Nieminen, Anne; Bamford, Jaana K H; Buckling, Angus

    2011-12-23

    Antibiotic-resistance genes are often carried by conjugative plasmids, which spread within and between bacterial species. It has long been recognized that some viruses of bacteria (bacteriophage; phage) have evolved to infect and kill plasmid-harbouring cells. This raises a question: can phages cause the loss of plasmid-associated antibiotic resistance by selecting for plasmid-free bacteria, or can bacteria or plasmids evolve resistance to phages in other ways? Here, we show that multiple antibiotic-resistance genes containing plasmids are stably maintained in both Escherichia coli and Salmonella enterica in the absence of phages, while plasmid-dependent phage PRD1 causes a dramatic reduction in the frequency of antibiotic-resistant bacteria. The loss of antibiotic resistance in cells initially harbouring RP4 plasmid was shown to result from evolution of phage resistance where bacterial cells expelled their plasmid (and hence the suitable receptor for phages). Phages also selected for a low frequency of plasmid-containing, phage-resistant bacteria, presumably as a result of modification of the plasmid-encoded receptor. However, these double-resistant mutants had a growth cost compared with phage-resistant but antibiotic-susceptible mutants and were unable to conjugate. These results suggest that bacteriophages could play a significant role in restricting the spread of plasmid-encoded antibiotic resistance.

  13. Rapid antimicrobial susceptibility testing with electrokinetics enhanced biosensors for diagnosis of acute bacterial infections.

    Science.gov (United States)

    Liu, Tingting; Lu, Yi; Gau, Vincent; Liao, Joseph C; Wong, Pak Kin

    2014-11-01

    Rapid pathogen detection and antimicrobial susceptibility testing (AST) are required in diagnosis of acute bacterial infections to determine the appropriate antibiotic treatment. Molecular approaches for AST are often based on the detection of known antibiotic resistance genes. Phenotypic culture analysis requires several days from sample collection to result reporting. Toward rapid diagnosis of bacterial infection in non-traditional healthcare settings, we have developed a rapid AST approach that combines phenotypic culture of bacterial pathogens in physiological samples and electrochemical sensing of bacterial 16S rRNA. The assay determines the susceptibility of pathogens by detecting bacterial growth under various antibiotic conditions. AC electrokinetic fluid motion and Joule heating induced temperature elevation are optimized to enhance the sensor signal and minimize the matrix effect, which improve the overall sensitivity of the assay. The electrokinetics enhanced biosensor directly detects the bacterial pathogens in blood culture without prior purification. Rapid determination of the antibiotic resistance profile of Escherichia coli clinical isolates is demonstrated.

  14. Rapid identification of antibiotic resistance using droplet microfluidics.

    Science.gov (United States)

    Keays, Marie C; O'Brien, Mark; Hussain, Anam; Kiely, Patrick A; Dalton, Tara

    2016-04-02

    Culturing bacteria and monitoring bacterial cell growth is a critical issue when dealing with patients who present with bacterial infections. One of the main challenges that arises is the time taken to identify the particular strain of bacteria and consequently, decide the correct treatment. In the majority of cases, broad spectrum antibiotics are used to target infections when a narrow spectrum drug would be more appropriate. The efficient monitoring of bacterial growth and potential antibiotic resistance is necessary to identify the best treatment options for patients. Minturising the reactions into microfluidic droplets offers a novel method to rapidy analyze bacteria. Microfluidics facilitates low volume reactions that provide a unique system where each droplet reaction acts as an individual bioreactor. Here, we designed and built a novel platform that allowed us to create and monitor E.coli microfluidic droplet cultures. Optical capacity was built in and measurements of bacterial cultures were captured facilitating the continuous monitoring of individual reactions. The capacity of the instrument was demonstrated by the application of treatments to both bacteria and drug resistant strains of bacteria. We were able to detect responses within one hour in the droplet cultures, demonstrating the capacity of this workflow to the culture and rapid characterization of bacterial strains.

  15. Simulation Study for Transfer of Antibiotic Resistance via Mutator Subpopulation

    DEFF Research Database (Denmark)

    Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Aarestrup, Frank Møller

    Evolution of antibiotic resistance in bacterial populations is an increasing problem having fatal consequences for treatment of diseases. Therefore it is very important to understand this evolution. Traditionally evolution is considered to happen by single point mutations, where each mutant must...... have a growth advantage over the parent strain and grow to a sufficient number before a second mutation can occur. However, when multiple mutations are necessary for development of resistance, single mutations occurring with a normal mutation rate can not always explain the observed resistance. We...... introduce an alternative hypothesis by which a subpopulation of mutators drives the evolution process. Resistance is acquired by a subpoplution of mutators, for which the mutation rate is much higher than the wild-type. If the resistance is located on a transferable plasmid it can subsequently...

  16. 228例新生儿血培养分离菌及耐药性分析%Pathogens and antibiotic resistance of lsolates from 228 cases newborn septicemia biood cultures

    Institute of Scientific and Technical Information of China (English)

    刘玉线; 刘冬霞; 张广清

    2015-01-01

    Objective To investigate the pathogen constitutes of neonatal blood culture and drug resistance,provide an objective basis for clinical rational use of antimicrobial drugs. Methods France bioMérieux BacT/Alert 3D blood culture instrument was used for Blood culture,and DL-96 Ⅱ -automatic bacterial identification system was used for bacterial identification and susceptibility testing. Results A total of 228 cases neonatal blood culture positive,the positive rate of 4.68%(228/4867).Gram-positive bacteria accounting for 67.1%(153/228),including staphylococcus epidermidis accounting(42.1%);Gram-negative bacteria(32.0%);Susceptibility results showed Gram-positive bacteria has the highest resistant rate to penicillin G,and has 100.0% sensitive rate for vancomycin,linezolid,teicoplanin;Gram-negative bacteria were sensitive to carbapenems antibiotics. Conclusion Hospital coagulase-negative staphylococci as the principal for our hospital neonatal septicemia pathogenic bacteria,clinicians keep abreast of the results of blood cultures and take appropriate antimicrobial therapy,is important for improve the cure rate and control of cross infection.%目的:了解本院新生儿血培养的病原菌构成及耐药性情况,为指导临床合理应用抗菌药物,提供客观依据。方法采用法国生物梅里埃公司 BacT/Alert 3D 血培养仪进行血培养,所有菌株采用珠海黑马生物有限公司 DL-96Ⅱ型全自动细菌鉴定仪进行鉴定及药敏试验。结果送检的4867例新生儿血培养阳性228例,阳性率4.68%。其中革兰阳性菌153株,占67.1%,并以表皮葡萄球菌为主,占42.1%;革兰阴性菌73株,占32.0%。药敏结果显示革兰阳性菌对青霉素 G 耐药率最高,对万古霉素、利奈唑胺、替考拉宁100.0%敏感;革兰阴性菌对碳青霉烯类抗菌药物均敏感。结论本院新生儿败血症病原菌以凝固酶阴性葡萄球菌为主,临床医生及时了解血培养的结果并采取

  17. Inhibition of mutation and combating the evolution of antibiotic resistance.

    Directory of Open Access Journals (Sweden)

    Ryan T Cirz

    2005-06-01

    Full Text Available The emergence of drug-resistant bacteria poses a serious threat to human health. In the case of several antibiotics, including those of the quinolone and rifamycin classes, bacteria rapidly acquire resistance through mutation of chromosomal genes during therapy. In this work, we show that preventing induction of the SOS response by interfering with the activity of the protease LexA renders pathogenic Escherichia coli unable to evolve resistance in vivo to ciprofloxacin or rifampicin, important quinolone and rifamycin antibiotics. We show in vitro that LexA cleavage is induced during RecBC-mediated repair of ciprofloxacin-mediated DNA damage and that this results in the derepression of the SOS-regulated polymerases Pol II, Pol IV and Pol V, which collaborate to induce resistance-conferring mutations. Our findings indicate that the inhibition of mutation could serve as a novel therapeutic strategy to combat the evolution of antibiotic resistance.

  18. Trends in antibiotic resistance among major bacterial pathogens isolated from blood cultures tested at a large private laboratory network in India, 2008–2014

    Directory of Open Access Journals (Sweden)

    Sumanth Gandra

    2016-09-01

    Conclusion: Increasing resistance to antibiotics of last-resort, particularly among Gram-negatives, suggests an urgent need for new antibiotics and improved antimicrobial stewardship programs in India.

  19. Antibiotic Resistance Determinant-Focused Acinetobacter baumannii Vaccine Designed Using Reverse Vaccinology

    Science.gov (United States)

    Ni, Zhaohui; Chen, Yan; Ong, Edison; He, Yongqun

    2017-01-01

    As one of the most influential and troublesome human pathogens, Acinetobacter baumannii (A. baumannii) has emerged with many multidrug-resistant strains. After collecting 33 complete A. baumannii genomes and 84 representative antibiotic resistance determinants, we used the Vaxign reverse vaccinology approach to predict classical type vaccine candidates against A. baumannii infections and new type vaccine candidates against antibiotic resistance. Our genome analysis identified 35 outer membrane or extracellular adhesins that are conserved among all 33 genomes, have no human protein homology, and have less than 2 transmembrane helices. These 35 antigens include 11 TonB dependent receptors, 8 porins, 7 efflux pump proteins, and 2 fimbrial proteins (FilF and CAM87009.1). CAM86003.1 was predicted to be an adhesin outer membrane protein absent from 3 antibiotic-sensitive strains and conserved in 21 antibiotic-resistant strains. Feasible anti-resistance vaccine candidates also include one extracellular protein (QnrA), 3 RND type outer membrane efflux pump proteins, and 3 CTX-M type β-lactamases. Among 39 β-lactamases, A. baumannii CTX-M-2, -5, and -43 enzymes are predicted as adhesins and better vaccine candidates than other β-lactamases to induce preventive immunity and enhance antibiotic treatments. This report represents the first reverse vaccinology study to systematically predict vaccine antigen candidates against antibiotic resistance for a microbial pathogen. PMID:28230771

  20. Mass spectrometry-based bacterial proteomics: focus on dermatological associated microbial pathogens

    Directory of Open Access Journals (Sweden)

    Youcef eSoufi

    2016-02-01

    Full Text Available The composition of human skin acts as a natural habitat for various bacterial species that function in a commensal and symbiotic fashion. In a healthy individual, bacterial flora serves to protect the host. Under certain conditions such as minor trauma, impaired host immunity, or environmental factors, the risk of developing skin infections is increased. Although a large majority of bacterial associated skin infections are common, a portion can potentially manifest into clinically significant morbidity. For example, Gram positive species that typically reside on the skin such as Staphylococcus and Streptococcus can cause numerous epidermal (impetigo, ecthyma and dermal (cellulitis, necrotizing fasciitis, erysipelas skin infections. Moreover, the increasing incidence of bacterial antibiotic resistance represents a serious challenge to modern medicine and threatens the health care system. Therefore, it is critical to develop tools and strategies that can allow us to better elucidate the nature and mechanism of bacterial virulence. To this end, mass spectrometry (MS-based proteomics has been revolutionizing biomedical research, and has positively impacted the microbiology field. Advances in MS technologies have paved the way for numerous bacterial proteomes and their respective post translational modifications (PTMs to be accurately identified and quantified in a high throughput and robust fashion. This technological platform offers critical information with regards to signal transduction, adherence, and microbial-host interactions associated with bacterial pathogenesis. This mini-review serves to highlight the current progress proteomics has contributed towards the understanding of bacteria that are associated with skin related diseases, infections, and antibiotic resistance.

  1. 革兰氏阴性细菌外膜蛋白耐药功能及其抑菌策略研究进展%An review on the antibiotics resistance function of outer membrane protein in gram-negative bacterial and related antimicrobial strategies

    Institute of Scientific and Technical Information of China (English)

    李碗芯; 孙莉娜; 林向民

    2015-01-01

    The emergence of bacterial resistance to drug use has posed serious problem worldwide. Generally, the drug resistance ca-pability of gram-negative bacteria is stronger than that of gram-positive, which is partially attributed to the antibiotics resistance of the outer membrane proteins ( OMPs) . It is well known that the specific OMPs efflux antibiotics out or inhibits uptakes of antibiot-ics, while the regulation mechanism remains uncertain. With the development of modern science and technology, especially the ap-plication of structure biology, molecular biology and proteomics, many progressive studies have unveiled the mechanisms underlying the antibiotic resistance of OMPs. This review focuses on the recent advances in the structure and antibiotic resistance mechanisms of OMP, which provides helpful insight into manufacture of new OMPs-targeting antimicrobial drug.%当前细菌耐药的形势日益严峻,已引起全世界的广泛关注.革兰氏阴性细菌的耐药性普遍比革兰氏阳性细菌强,这与镶嵌或锚定在革兰氏阴性细菌外膜上的蛋白耐药功能密切相关.目前已知外膜蛋白能够阻碍抗生素通过外膜以及将抗生素排出胞外等方式使细菌产生耐药性,但具体的耐药与调控机制还有待进一步研究.近年来,随着现代科学技术的不断发展,特别是结构生物学、分子生物学与蛋白质组学在该领域的充分运用,有关外膜蛋白功能的研究和技术取得了很大的进步.本文对近年来国内外在细菌外膜蛋白的结构与耐药机理、耐药新功能及新机制等方面的研究进展进行了概述,为揭示革兰氏阴性菌耐药形成机制奠定基础.

  2. Investigation of septins using infection by bacterial pathogens.

    Science.gov (United States)

    Krokowski, S; Mostowy, S

    2016-01-01

    Investigation of the host cytoskeleton during infection by bacterial pathogens has significantly contributed to our understanding of cell biology and host defense. Work has shown that septins are recruited to the phagocytic cup as collarlike structures and enable bacterial entry into host cells. In the cytosol, septins can entrap actin-polymerizing bacteria in cage-like structures for targeting to autophagy, a highly conserved intracellular degradation process. In this chapter, we describe methods to investigate septin assembly and function during infection by bacterial pathogens. Use of these methods can lead to in-depth understanding of septin biology and suggest therapeutic approaches to combat infectious disease.

  3. Antibiotic resistance: are we all doomed?

    Science.gov (United States)

    Collignon, P

    2015-11-01

    Antibiotic resistance is a growing and worrying problem associated with increased deaths and suffering for people. Overall, there are only two factors that drive antimicrobial resistance, and both can be controlled. These factors are the volumes of antimicrobials used and the spread of resistant micro-organisms and/or the genes encoding for resistance. The One Health concept is important if we want to understand better and control antimicrobial resistance. There are many things we can do to better control antimicrobial resistance. We need to prevent infections. We need to have better surveillance with good data on usage patterns and resistance patterns available across all sectors, both human and agriculture, locally and internationally. We need to act on these results when we see either inappropriate usage or resistance levels rising in bacteria that are of concern for people. We need to ensure that food and water sources do not spread multi-resistant micro-organisms or resistance genes. We need better approaches to restrict successfully what and how antibiotics are used in people. We need to restrict the use of 'critically important' antibiotics in food animals and the entry of these drugs into the environment. We need to ensure that 'One Health' concept is not just a buzz word but implemented. We need to look at all sectors and control not only antibiotic use but also the spread and development of antibiotic resistant bacteria - both locally and internationally.

  4. The world alliance against antibiotic resistance: consensus for a declaration.

    Science.gov (United States)

    Carlet, Jean

    2015-06-15

    Antibiotic resistance is increasing worldwide and has become a very important threat to public health. The overconsumption of antibiotics is the most important cause of this problem. We created a World Alliance Against Antibiotic Resistance (WAAAR), which now includes 720 people from 55 different countries and is supported by 145 medical societies or various groups. In June 2014, WAAAR launched a declaration against antibiotic resistance. This article describes the process and the content of this declaration.

  5. Fighting antibiotic resistance in the intensive care unit using antibiotics.

    Science.gov (United States)

    Plantinga, Nienke L; Wittekamp, Bastiaan H J; van Duijn, Pleun J; Bonten, Marc J M

    2015-01-01

    Antibiotic resistance is a global and increasing problem that is not counterbalanced by the development of new therapeutic agents. The prevalence of antibiotic resistance is especially high in intensive care units with frequently reported outbreaks of multidrug-resistant organisms. In addition to classical infection prevention protocols and surveillance programs, counterintuitive interventions, such as selective decontamination with antibiotics and antibiotic rotation have been applied and investigated to control the emergence of antibiotic resistance. This review provides an overview of selective oropharyngeal and digestive tract decontamination, decolonization of methicillin-resistant Staphylococcus aureus and antibiotic rotation as strategies to modulate antibiotic resistance in the intensive care unit.

  6. Distribution characteristics and antibiotic resistance analysis of pathogens from diabetic foot infection in recent 15 years%糖尿病足感染病原菌特点及耐药性15年变迁

    Institute of Scientific and Technical Information of China (English)

    黄莺; 曹瑛; 邹梦晨; 李文霞; 罗祥蓉; 蒋娅; 薛耀明; 高方

    2016-01-01

    foot patients and analyze the drug susceptibility so as to provide guidance for reasonable clinical use of antibiotics. Methods A retrospective study was carried out on the clinical materials from 580 patients with diabetic foot infections hospitalized in Nanfang Hospital from January 2000 to December 2014. The patients were grouped according to Wagner grading and type of ulcers. Seasons were classified by pentad mean temperature method, then the distribution characteristics of pathogens in different groups was analyzed. And the data were divided into two phases according to the variation trend of drug resistance as follow:from 2000 to 2010, from 2011 to 2014, then analysis was carried out on the change of drug resistance in recent 15 years. The data among groups were compared by usingχ2 test. Results Among 580 cases, there were 347 males(59.8%) and 233 females(40.2%), mean age was 35-87(62±12) years, duration of diabetes was 0-35(8± 6) years. And 349(46.8%) strains of gram-positive bacteria, 354(47.4%) strains of gram-negative bacteria and 43(5.8%) strains of fungi were isolated from ulcers. With rising Wagner grade, bacterial floras transformed from Gram-positive bacteria (62.3%in Wagner grade≤2) to Gram-negative bacteria (61.7%in Wagner grade≥4) while composite infections increased(χ2=24.645, P<0.05). Gram-positive bacteria were the main pathogens of diabetic foot ulcers in neuropathic ulcers(51.7%) while Gram-negative bacteria were the most frequently isolated in ischemic and neuroischemic ulcers(60.9%, 53.0%). There were significant difference in distribution of pathogens among ulcers with different Wagner grades and different types(χ2=37.383, 13.045, P<0.05). The distribution of pathogens was influenced by seasons in Wagner grade 3 ulcers. Gram-negative bacteria were the most frequently isolated in summer(55.5%) while gram-positive bacteria were the most common in spring or autumn(60.1%) (χ2=17.740, P<0.05). Among Gram-positive bacteria, Staphylococci

  7. Impact of urban contamination of the La Paz River basin on thermotolerant coliform density and occurrence of multiple antibiotic resistant enteric pathogens in river water, irrigated soil and fresh vegetables.

    Science.gov (United States)

    Poma, Violeta; Mamani, Nataniel; Iñiguez, Volga

    2016-01-01

    present. Moreover, some Salmonella isolates were distinguished by their multi-resistance to ≥8 antibiotics, within soil and vegetable samples. Overall, this study demonstrates that La Paz River-an affluent of the Amazon macrobasin-is heavily polluted along the year with a high density of thermotolerant coliforms and is a reservoir of multiple antibiotic resistant enteropathogens, present in river water, soil and vegetables. These data highlight health risk associated with food and waterborne diseases at the region.

  8. Addressing the antibiotic resistance problem with probiotics: Reducing the risk of its double-edged sword effect

    Directory of Open Access Journals (Sweden)

    Ivan Christian VJ Imperial

    2016-12-01

    Full Text Available Antibiotic resistance is a global public health problem that requires our attention. Indiscriminate antibiotic use is a major contributor in the introduction of selective pressures in our natural environments that have significantly contributed in the rapid emergence of antibiotic-resistant microbial strains. The use of probiotics in lieu of antibiotic therapy to address certain health conditions in both animals and humans may alleviate these antibiotic-mediated selective pressures. Probiotic use is defined as the actual application of live beneficial microbes to obtain a desired outcome by preventing diseased state or improving general health. Multiple studies have confirmed the beneficial effects of probiotic use in the health of both livestock and humans. As such, probiotics consumption is gaining popularity worldwide. However, concerns have been raised in the use of some probiotics strains that carry antibiotic resistance genes themselves, as they have the potential to pass the antibiotic resistance genes to pathogenic bacteria through horizontal gene transfer. Therefore, with the current public health concern on antibiotic resistance globally, in this review, we underscore the need to screen probiotic strains that are used in both livestock and human applications to assure their safety and mitigate their potential in significantly contributing to the spread of antibiotic resistance genes in our natural environments.

  9. Genomic and Transcriptomic Analyses of Foodborne Bacterial Pathogens

    Science.gov (United States)

    Zhang, Wei; Dudley, Edward G.; Wade, Joseph T.

    DNA microarrays (often interchangeably called DNA chips or DNA arrays) are among the most popular analytical tools for high-throughput comparative genomic and transcriptomic analyses of foodborne bacterial pathogens. A typical DNA microarray contains hundreds to millions of small DNA probes that are chemically attached (or "printed") onto the surface of a microscopic glass slide. Depending on the specific "printing" and probe synthesis technologies for different microarray platforms, such DNA probes can be PCR amplicons or in situ synthesized short oligonucleotides. DNA microarray technologies have revolutionized the way that we investigate the biology of foodborne bacterial pathogens. The major advantage of these technologies is that DNA microarrays allow comparison of subtle genomic or transcriptomic variations between two bacterial samples, such as genomic variations between two different bacterial strains or transcriptomic alterations of same bacterial strain under two different treatments. Some applications of comparative genomic hybridization microarrays and global gene expression microarrays have been covered in previous chapters of this book.

  10. Mobile antibiotic resistance encoding elements promote their own diversity.

    Directory of Open Access Journals (Sweden)

    Geneviève Garriss

    2009-12-01

    Full Text Available Integrating conjugative elements (ICEs are a class of bacterial mobile genetic elements that disseminate via conjugation and then integrate into the host cell genome. The SXT/R391 family of ICEs consists of more than 30 different elements that all share the same integration site in the host chromosome but often encode distinct properties. These elements contribute to the spread of antibiotic resistance genes in several gram-negative bacteria including Vibrio cholerae, the agent of cholera. Here, using comparative analyses of the genomes of several SXT/R391 ICEs, we found evidence that the genomes of these elements have been shaped by inter-ICE recombination. We developed a high throughput semi-quantitative method to explore the genetic determinants involved in hybrid ICE formation. Recombinant ICE formation proved to be relatively frequent, and to depend on host (recA and ICE (s065 and s066 loci, which can independently and potentially cooperatively mediate hybrid ICE formation. s065 and s066, which are found in all SXT/R391 ICEs, are orthologues of the bacteriophage lambda Red recombination genes bet and exo, and the s065/s066 recombination system is the first Red-like recombination pathway to be described in a conjugative element. Neither ICE excision nor conjugative transfer proved to be essential for generation of hybrid ICEs. Instead conjugation facilitates the segregation of hybrids and could provide a means to select for functional recombinant ICEs containing novel combinations of genes conferring resistance to antibiotics. Thus, ICEs promote their own diversity and can yield novel mobile elements capable of disseminating new combinations of antibiotic resistance genes.

  11. Recent investigations and updated criteria for the assessment of antibiotic resistance in food lactic acid bacteria.

    Science.gov (United States)

    Clementi, Francesca; Aquilanti, Lucia

    2011-12-01

    The worldwide use, and misuse, of antibiotics for about sixty years in the so-called antibiotic era, has been estimated in some one to ten million tons, a relevant part of which destined for non-therapeutic purposes such as growth promoting treatments for livestock or crop protection. As highly adaptable organisms, bacteria have reacted to this dramatic change in their environment by developing several well-known mechanisms of antibiotic resistance and are becoming increasingly resistant to conventional antibiotics. In recent years, commensal bacteria have become a cause of concern since they may act as reservoirs for the antibiotic resistance genes found in human pathogens. In particular, the food chain has been considered the main route for the introduction of animal and environment associated antibiotic resistant bacteria into the human gastrointestinal tract (GIT) where these genes may be transferred to pathogenic and opportunistic bacteria. As fundamental microbial communities in a large variety of fermented foods and feed, the anaerobe facultative, aerotolerant lactic acid bacteria (LAB) are likely to play a pivotal role in the resistance gene exchange occurring in the environment, food, feed and animal and human GIT. Therefore their antibiotic resistance features and their genetic basis have recently received increasing attention. The present article summarises the results of the latest studies on the most typical genera belonging to the low G + C branch of LAB. The evolution of the criteria established by European regulatory bodies to ensure a safe use of microorganisms in food and feed, including the assessment of their antibiotic resistance is also reviewed.

  12. Functional Screening of Antibiotic Resistance Genes from a Representative Metagenomic Library of Food Fermenting Microbiota

    Directory of Open Access Journals (Sweden)

    Chiara Devirgiliis

    2014-01-01

    Full Text Available Lactic acid bacteria (LAB represent the predominant microbiota in fermented foods. Foodborne LAB have received increasing attention as potential reservoir of antibiotic resistance (AR determinants, which may be horizontally transferred to opportunistic pathogens. We have previously reported isolation of AR LAB from the raw ingredients of a fermented cheese, while AR genes could be detected in the final, marketed product only by PCR amplification, thus pointing at the need for more sensitive microbial isolation techniques. We turned therefore to construction of a metagenomic library containing microbial DNA extracted directly from the food matrix. To maximize yield and purity and to ensure that genomic complexity of the library was representative of the original bacterial population, we defined a suitable protocol for total DNA extraction from cheese which can also be applied to other lipid-rich foods. Functional library screening on different antibiotics allowed recovery of ampicillin and kanamycin resistant clones originating from Streptococcus salivarius subsp. thermophilus and Lactobacillus helveticus genomes. We report molecular characterization of the cloned inserts, which were fully sequenced and shown to confer AR phenotype to recipient bacteria. We also show that metagenomics can be applied to food microbiota to identify underrepresented species carrying specific genes of interest.

  13. Antibiotic Resistance Pattern in Pseudomonas Aeruginosa Species Isolated at a Tertiary Care Hospital, Ahmadabad

    Directory of Open Access Journals (Sweden)

    Rajat Rakesh M

    2012-04-01

    Full Text Available Introduction: Pseudomonas aeruginosa (Ps.aeruginosa is one of the important bacterial pathogens isolated from various samples. Despite advances in medical and surgical care and introduction of wide variety of antimicrobial agents against having anti-pseudomonal activities, life threatening infection caused by Ps. aeruginosa continues to cause complications in hospital acquired infections. Several different epidemiological studies indicate that antibiotic resistance is increasing in clinical isolates. Material and Method: This study was conducted during April 2009 to april 2010. During this period total of 630 samples were tested, in which 321 samples showed growth of bacteria. Out of 321 samples, 100 clinical isolates of Pseudomonas aeruginosa were isolated. The samples were selected on the basis of their growth on routine MacConkey medium which showed lactose Non-fermenting pale colonies which were oxidase test positive and on Nutrient agar pigmented and non-pigmented colonies with oxidase positive. Antimicrobial susceptibility of all the isolates was performed by the disc-diffusion (Modified-Kirby Baur disc diffusion method according to CLSIs guidelines. Result: In present study, maximum isolates of Ps. aeruginosa isolated from various samples are resistant to tobramycin (68% followed by gentamycin (63%, piperacillin (50%, ciprofloxacin (49% and ceftazidime (43%. Conclusion: To prevent the spread of the resistant bacteria, it is critically important to have strict antibiotic policies while surveillance programmes for multidrug resistant organisms and infection control procedures need to be implemented. [National J of Med Res 2012; 2(2.000: 156-159

  14. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria.

    Science.gov (United States)

    Li, Xian-Zhi; Plésiat, Patrick; Nikaido, Hiroshi

    2015-04-01

    The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.

  15. Contamination of lettuce with antibiotic resistant E. coli after slurry application

    DEFF Research Database (Denmark)

    Jensen, Annette Nygaard; Storm, Christina; Baggesen, Dorte Lau

    2011-01-01

    was therefore performed to assess the survival and transfer of antibiotic-resistant E. coli from animal manure to lettuces, with E. coli serving as an indicator of bacterial enteric pathogens. Animal slurry was applied to 3 Danish fields prior to planting of lettuce seedlings, then 5-8 weeks later at the normal...... time of harvest, inner and outer leafs of 10 lettuce heads were pooled into one sample unit with a total of 50 pools per field. Additionally, in one field, 15 soil samples were collected weekly until the harvest time. E. coli was enumerated by plating 1 mL of 10-fold serial dilutions of 5 g...... of homogenized sample material, i.e. manure, soil and lettuce onto PetrifilmTM Select E. coli count plates (3M) containing 16 mg/L streptomycin or 16 mg/L ampicilin or no antibiotics. Plates were then incubated 24 h at 44°C. Selected isolates of E. coli (n=83) from slurry, soil and lettuce were analysed by PFGE...

  16. A pseudo-tRNA modulates antibiotic resistance in Bacillus cereus.

    Directory of Open Access Journals (Sweden)

    Theresa E Rogers

    Full Text Available Bacterial genomic islands are often flanked by tRNA genes, which act as sites for the integration of foreign DNA into the host chromosome. For example, Bacillus cereus ATCC14579 contains a pathogenicity island flanked by a predicted pseudo-tRNA, tRNA(Other, which does not function in translation. Deletion of tRNA(Other led to significant changes in cell wall morphology and antibiotic resistance and was accompanied by changes in the expression of numerous genes involved in oxidative stress responses, several of which contain significant complementarities to sequences surrounding tRNA(Other. This suggested that tRNA(Other might be expressed as part of a larger RNA, and RACE analysis subsequently confirmed the existence of several RNA species that significantly extend both the 3' and 5'-ends of tRNA(Other. tRNA(Other expression levels were found to be responsive to changes in extracellular iron concentration, consistent with the presence of three putative ferric uptake regulator (Fur binding sites in the 5' leader region of one of these larger RNAs. Taken together with previous data, this study now suggests that tRNA(Other may function by providing a tRNA-like structural element within a larger regulatory RNA. These findings illustrate that while integration of genomic islands often leaves tRNA genes intact and functional, in other instances inactivation may generate tRNA-like elements that are then recruited to other functions in the cell.

  17. Molecular basis of NDM-1, a new antibiotic resistance determinant.

    Directory of Open Access Journals (Sweden)

    Zhongjie Liang

    Full Text Available The New Delhi Metallo-β-lactamase (NDM-1 was first reported in 2009 in a Swedish patient. A recent study reported that Klebsiella pneumonia NDM-1 positive strain or Escherichia coli NDM-1 positive strain was highly resistant to all antibiotics tested except tigecycline and colistin. These can no longer be relied on to treat infections and therefore, NDM-1 now becomes potentially a major global health threat.In this study, we performed modeling studies to obtain its 3D structure and NDM-1/antibiotics complex. It revealed that the hydrolytic mechanisms are highly conserved. In addition, the detailed analysis indicates that the more flexible and hydrophobic loop1, together with the evolution of more positive-charged loop2 leads to NDM-1 positive strain more potent and extensive in antibiotics resistance compared with other MBLs. Furthermore, through biological experiments, we revealed the molecular basis for antibiotics catalysis of NDM-1 on the enzymatic level. We found that NDM-1 enzyme was highly potent to degrade carbapenem antibiotics, while mostly susceptible to tigecycline, which had the ability to slow down the hydrolysis velocity of meropenem by NDM-1. Meanwhile, the mutagenesis experiments, including D124A, C208A, K211A and K211E, which displayed down-regulation on meropenem catalysis, proved the accuracy of our model.At present, there are no effective antibiotics against NDM-1 positive pathogen. Our study will provide clues to investigate the molecular basis of extended antibiotics resistance of NDM-1 and then accelerate the search for new antibiotics against NDM-1 positive strain in clinical studies.

  18. Molecular basis of NDM-1, a new antibiotic resistance determinant.

    Science.gov (United States)

    Liang, Zhongjie; Li, Lianchun; Wang, Yuanyuan; Chen, Limin; Kong, Xiangqian; Hong, Yao; Lan, Lefu; Zheng, Mingyue; Guang-Yang, Cai; Liu, Hong; Shen, Xu; Luo, Cheng; Li, Keqin Kathy; Chen, Kaixian; Jiang, Hualiang

    2011-01-01

    The New Delhi Metallo-β-lactamase (NDM-1) was first reported in 2009 in a Swedish patient. A recent study reported that Klebsiella pneumonia NDM-1 positive strain or Escherichia coli NDM-1 positive strain was highly resistant to all antibiotics tested except tigecycline and colistin. These can no longer be relied on to treat infections and therefore, NDM-1 now becomes potentially a major global health threat.In this study, we performed modeling studies to obtain its 3D structure and NDM-1/antibiotics complex. It revealed that the hydrolytic mechanisms are highly conserved. In addition, the detailed analysis indicates that the more flexible and hydrophobic loop1, together with the evolution of more positive-charged loop2 leads to NDM-1 positive strain more potent and extensive in antibiotics resistance compared with other MBLs. Furthermore, through biological experiments, we revealed the molecular basis for antibiotics catalysis of NDM-1 on the enzymatic level. We found that NDM-1 enzyme was highly potent to degrade carbapenem antibiotics, while mostly susceptible to tigecycline, which had the ability to slow down the hydrolysis velocity of meropenem by NDM-1. Meanwhile, the mutagenesis experiments, including D124A, C208A, K211A and K211E, which displayed down-regulation on meropenem catalysis, proved the accuracy of our model.At present, there are no effective antibiotics against NDM-1 positive pathogen. Our study will provide clues to investigate the molecular basis of extended antibiotics resistance of NDM-1 and then accelerate the search for new antibiotics against NDM-1 positive strain in clinical studies.

  19. Looking in ticks for human bacterial pathogens.

    Science.gov (United States)

    Mediannikov, O; Fenollar, F

    2014-12-01

    Ticks are considered to be second worldwide to mosquitoes as vectors of human diseases and the most important vectors of disease-causing pathogens in domestic and wild animals. A number of emerging tick-borne pathogens are already discovered; however, the proportion of undiagnosed infectious diseases, especially in tropical regions, may suggest that there are still more pathogens associated with ticks. Moreover, the identification of bacteria associated with ticks may provide new tool for the control of ticks and tick-borne diseases. Described here molecular methods of screening of ticks, extensive use of modern culturomics approach, newly developed artificial media and different cell line cultures may significantly improve our knowledge about the ticks as the agents of human and animal pathology.

  20. Selection of antibiotic-resistant standard plate count bacteria during water treatment.

    Science.gov (United States)

    Armstrong, J L; Calomiris, J J; Seidler, R J

    1982-08-01

    Standard plate count (SPC) bacteria were isolated from a drinking-water treatment facility and from the river supplying the facility. All isolates were identified and tested for their resistance to six antibiotics to determine if drug-resistant bacteria were selected for as a consequence of water treatment. Among the isolates surviving our test procedures, there was a significant selection (P less than 0.05) of gram-negative SPC organisms resistant to two or more of the test antibiotics. These bacteria were isolated from the flash mix tank, where chlorine, alum, and lime are added to the water. Streptomycin resistance in particular was more frequent in this population as compared with bacteria in the untreated river water (P less than 0.01). SPC bacteria from the clear well, which is a tank holding the finished drinking water at the treatment facility, were also more frequently antibiotic resistant than were the respective river water populations. When 15.8 and 18.2% of the river water bacteria were multiply antibiotic resistant, 57.1 and 43.5%, respectively, of the SPC bacteria in the clear well were multiply antibiotic resistant. Selection for bacteria exhibiting resistance to streptomycin was achieved by chlorinating river water in the laboratory. We concluded that the selective factors operating in the aquatic environment of a water treatment facility can act to increase the proportion of antibiotic-resistant members of the SPC bacterial population in treated drinking water.

  1. Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC).

    Science.gov (United States)

    Colello, Rocío; Etcheverría, Analía I; Di Conza, Jose A; Gutkind, Gabriel O; Padola, Nora L

    2015-03-01

    Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome in humans (HUS). Cattle are the main reservoir of STEC and transmission to humans occurs through contaminated food and water. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in the dissemination of antibiotic resistance genes to the bacteria. Integrons have been identified in resistant bacteria allowing for the acquisition and dissemination of antibiotic resistance genes. STEC strains isolated from humans and animals have developed antibiotic resistance. In our laboratory, 21 non-157 STEC strains isolated from pigs were analyzed to detect class 1 and 2 integrons by PCR. Eight carried integrons, 7 of them harbored intl2. In another study 545 STEC strains were also analyzed for the presence of intl1 and intl2 . Strains carrying intl1 belonged to isolates from environment (n = 1), chicken hamburger (n = 2), dairy calves (n = 4) and pigs (n = 8). Two strains isolated from pigs harbored intl2 and only one intl1 / intl2 , highlighting the presence of intl2 in pigs. The selection for multiresistant strains may contribute to the emergence of antibiotic resistant pathogens and facilitate the spreading of the mobile resistance elements to other bacteria.

  2. Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC

    Directory of Open Access Journals (Sweden)

    Rocío Colello

    2015-03-01

    Full Text Available Shiga toxin-producing Escherichia coli (STEC cause hemorrhagic colitis (HC and hemolytic-uremic syndrome in humans (HUS. Cattle are the main reservoir of STEC and transmission to humans occurs through contaminated food and water. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in the dissemination of antibiotic resistance genes to the bacteria. Integrons have been identified in resistant bacteria allowing for the acquisition and dissemination of antibiotic resistance genes. STEC strains isolated from humans and animals have developed antibiotic resistance. In our laboratory, 21 non-157 STEC strains isolated from pigs were analyzed to detect class 1 and 2 integrons by PCR. Eight carried integrons, 7 of them harbored intl2. In another study 545 STEC strains were also analyzed for the presence of intl1 and intl2. Strains carrying intl1 belonged to isolates from environment (n = 1, chicken hamburger (n = 2, dairy calves (n = 4 and pigs (n = 8. Two strains isolated from pigs harbored intl2 and only one intl1/intl2, highlighting the presence of intl2 in pigs. The selection for multiresistant strains may contribute to the emergence of antibiotic resistant pathogens and facilitate the spreading of the mobile resistance elements to other bacteria.

  3. Antibiotic resistance patterns of Salmonella and Escherichia coli in the groundwater of Cyprus.

    Science.gov (United States)

    Economides, Constantinos; Liapi, Maria; Makris, Konstantinos C

    2012-08-01

    In addition to diet-based vectors of disease, the contribution of water-borne zoonotic agents to gastrointestinal illnesses may be significant, but this has yet to be investigated for Cyprus. Our main objective was to evaluate antibiotic resistance patterns of Salmonella and Escherichia coli in groundwater samples collected at confined animal feeding operations. This is the first report on the occurrence of antibiotic-resistant Salmonella and E. coli strains in the groundwater of Cyprus. Most of Salmonella isolates belonged to the subgroup enterica, whereas none of the E. coli isolates expressed the verotoxin-encoding gene. Out of 27 isolated Salmonella strains, nearly half of them were resistant to at least one or more antibiotic, whereas the highest resistance was exhibited by sulphamethoxazole (85%), followed by streptomycin (39%), and tetracycline (31%). For the E. coli isolates, nearly a third of them showed resistance to at least one antibiotic, whereas the selection of antibiotic resistance was equal among sulphamethoxazole, tetracycline and streptomycin (20%). This study demonstrated that Salmonella and E. coli in groundwater could pose a public health risk via oral ingestion of contaminated water. Best management practices are needed for overexploited groundwater supplies of rural areas, minimizing human exposure to antibiotic-resistant pathogens.

  4. Effect of analgesics and their derivatives on antibiotic resistance of environmental microbes.

    Science.gov (United States)

    Dhanapal, L P; Morse, A N

    2009-01-01

    This research is a preliminary study conducted to determine the effects of aspirin (acetyl-salicylic acid) and salicylic acid (analgesics and their derivatives) on the antibiotic resistance of ammonia oxidizing bacterium (AOB) (a non-pathogenic environmental microbe) cultured from the Texas Tech University-Water Recovery System that treats a space related wastewater for NASA. The effect of salicylic acid was investigated by obtaining the minimal inhibition concentration (MIC) of antibiotics (amoxicillin, ciprofloxacin, and nalidixic acid) in the presence of aspirin and salicylic acid. The possibility of transfer of resistance genes between unrelated species was investigated by analyzing the similarity of the AcrA protein (a multi-drug efflux protein) in Nitrosomonas europaea, Escherichia coli and Salmonella enterica. The protein alignment analysis was done using ExPASy, a proteomics tool. The results of this preliminary study indicated that the antibiotic resistance of AOBs increased in the presence of aspirin and salicylic acid and similarities in the AcrA protein of different species indicated the likelihood of possible resistance transfer between the species. This paper high lights the importance of research and further investigation on antibiotic resistance and resistance transfer, highlighting the number of parameters that should be considered while assessing antibiotic resistance in environmental samples.

  5. Insertion sequence IS256 in canine pyoderma isolates of Staphylococcus pseudintermedius associated with antibiotic resistance.

    Science.gov (United States)

    Casagrande Proietti, P; Bietta, A; Coletti, M; Marenzoni, M L; Scorza, A V; Passamonti, F

    2012-06-15

    Staphylococcus pseudintermedius is the most frequent staphylococcal species isolated from canine pyoderma. The control of S. pseudintermedius infection is often difficult due to the expanded antimicrobial resistance phenotypes. Antibiotic resistance in staphylococcal pathogens is often associated to mobile genetic elements such as the insertion sequence IS256 that was first described as a part of the transposon Tn4001, which confers aminoglycoside resistance in Staphylococcus aureus and in Staphylococcus epidermidis. In this study a collection of 70 S. pseudintermedius isolates from canine pyoderma was used to investigate antimicrobial susceptibility to 15 antibiotics and the presence of IS256, not revealed in S. pseudintermedius yet. Antibiotic resistance profiling demonstrated that all S. pseudintermedius isolates had a multi-drug resistance phenotype, exhibiting simultaneous resistance to at least five antibiotics; indeed methicillin resistant S. pseudintermedius isolates were simultaneously resistant to at least nine antibiotics and all were also gentamicin resistant. PCR analyses revealed the presence of IS256 in 43/70 S. pseudintemedius isolates. The association between the presence of IS256 and the resistance was particularly significant for certain antibiotics: cefovecin, amikacin, gentamicin and oxacillin (χ(2)p-valuepseudintermedius isolates and its association with antibiotic resistance. Our findings suggest that S. pseudintermedius may acquire antibiotic resistance genes through mobile genetic elements which may play a predominant role in the dissemination of multi-drug resistance.

  6. Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC)

    Science.gov (United States)

    Colello, Rocío; Etcheverría, Analía I.; Conza, Jose A. Di; Gutkind, Gabriel O.; Padola, Nora L.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome in humans (HUS). Cattle are the main reservoir of STEC and transmission to humans occurs through contaminated food and water. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in the dissemination of antibiotic resistance genes to the bacteria. Integrons have been identified in resistant bacteria allowing for the acquisition and dissemination of antibiotic resistance genes. STEC strains isolated from humans and animals have developed antibiotic resistance. In our laboratory, 21 non-157 STEC strains isolated from pigs were analyzed to detect class 1 and 2 integrons by PCR. Eight carried integrons, 7 of them harbored intl2. In another study 545 STEC strains were also analyzed for the presence of intl1 and intl2 . Strains carrying intl1 belonged to isolates from environment (n = 1), chicken hamburger (n = 2), dairy calves (n = 4) and pigs (n = 8). Two strains isolated from pigs harbored intl2 and only one intl1 / intl2 , highlighting the presence of intl2 in pigs. The selection for multiresistant strains may contribute to the emergence of antibiotic resistant pathogens and facilitate the spreading of the mobile resistance elements to other bacteria. PMID:26221083

  7. Cytosolic Access of Intracellular Bacterial Pathogens: The Shigella Paradigm.

    Science.gov (United States)

    Mellouk, Nora; Enninga, Jost

    2016-01-01

    Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.

  8. Antibiotic-Resistant Vibrios in Farmed Shrimp

    Directory of Open Access Journals (Sweden)

    Renata Albuquerque Costa

    2015-01-01

    Full Text Available Antimicrobial susceptibility pattern was determined in 100 strains of Vibrio isolated from the Litopenaeus vannamei shrimp and identified phenotypically. A high antibiotic-resistance index (75% was observed, with the following phenotypic profiles: monoresistance (n=42, cross-resistance to β-lactams (n=20 and multiple resistance (n=13. Plasmid resistance was characterized for penicillin (n=11, penicillin + ampicillin (n = 1, penicillin + aztreonam (n = 1, and ampicillin (n = 1. Resistance to antimicrobial drugs by the other strains (n=86 was possibly mediated by chromosomal genes. The findings of this study support the conclusion that the cultured shrimps can be vehicles of vibrios resistant to β-lactam and tetracycline.

  9. How to measure the impacts of antibiotic resistance and antibiotic development on empiric therapy: new composite indices

    Science.gov (United States)

    Hughes, Josie S; Hurford, Amy; Finley, Rita L; Patrick, David M; Wu, Jianhong; Morris, Andrew M

    2016-01-01

    Objectives We aimed to construct widely useable summary measures of the net impact of antibiotic resistance on empiric therapy. Summary measures are needed to communicate the importance of resistance, plan and evaluate interventions, and direct policy and investment. Design, setting and participants As an example, we retrospectively summarised the 2011 cumulative antibiogram from a Toronto academic intensive care unit. Outcome measures We developed two complementary indices to summarise the clinical impact of antibiotic resistance and drug availability on empiric therapy. The Empiric Coverage Index (ECI) measures susceptibility of common bacterial infections to available empiric antibiotics as a percentage. The Empiric Options Index (EOI) varies from 0 to ‘the number of treatment options available’, and measures the empiric value of the current stock of antibiotics as a depletable resource. The indices account for drug availability and the relative clinical importance of pathogens. We demonstrate meaning and use by examining the potential impact of new drugs and threatening bacterial strains. Conclusions In our intensive care unit coverage of device-associated infections measured by the ECI remains high (98%), but 37–44% of treatment potential measured by the EOI has been lost. Without reserved drugs, the ECI is 86–88%. New cephalosporin/β-lactamase inhibitor combinations could increase the EOI, but no single drug can compensate for losses. Increasing methicillin-resistant Staphylococcus aureus (MRSA) prevalence would have little overall impact (ECI=98%, EOI=4.8–5.2) because many Gram-positives are already resistant to β-lactams. Aminoglycoside resistance, however, could have substantial clinical impact because they are among the few drugs that provide coverage of Gram-negative infections (ECI=97%, EOI=3.8–4.5). Our proposed indices summarise the local impact of antibiotic resistance on empiric coverage (ECI) and available empiric treatment options

  10. Helicobacter pylori antibiotic resistance in Iran

    Institute of Scientific and Technical Information of China (English)

    Marjan Mohammadi; Delaram Doroud; Nazanin Mohajerani; Sadegh Massarrat

    2005-01-01

    AIM: To examine the frequency of antibiotic resistance in Iranian Helicobacter pylori(H pylori) strains isolated from two major hospitals in Tehran.METHODS: Examination of antibiotic resistance was performed on 120 strains by modified disc diffusion test and PCR-RFLP methods. In addition, in order to identify the possible causes of the therapeutic failure in Iran, we also determined the resistance of these strains to the most commonly used antibiotics (metronidazole, amoxicillin,and tetracycline) by modified disc diffusion test.RESULTS: According to modified disc diffusion test, 1.6% of the studied strains were resistant to amoxicillin, 16.7% to clarithromycin, 57.5% to metronidazole, and there was no resistance to tetracycline. Of the clarithromycin resistant strains, 73.68% had the A2143G mutation in the 23S rRNA gene, 21.05% A2142C, and 5.26% A2142G.None of the sensitive strains were positive for any of the three point mutations. Of the metronidazole resistant strains, deletion in rdxA gene was studied and detected in only 6 (5%) of the antibiogram-based resistant strains.None of the metronidazole sensitive strains possessed rdxA gene deletion.CONCLUSION: These data show that despite the fact that clarithromycin has not yet been introduced to the Iranian drug market as a generic drug, nearly 20% rate of resistance alerts toward the frequency of macrolide resistance strains, which may be due to the widespread prescription of erythromycin in Iran. rdxA gene inactivation,if present in Iranian H pylori strains, may be due to other genetic defects rather than gene deletion.

  11. Recognition of bacterial plant pathogens: local, systemic and transgenerational immunity.

    Science.gov (United States)

    Henry, Elizabeth; Yadeta, Koste A; Coaker, Gitta

    2013-09-01

    Bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. The plant innate immune system comprises extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (NLR) proteins that recognize specific bacterial effectors delivered into host cells. Plants lack the adaptive immune branch present in animals, but still afford flexibility to pathogen attack through systemic and transgenerational resistance. Here, we focus on current research in plant immune responses against bacterial pathogens. Recent studies shed light onto the activation and inactivation of pattern recognition receptors and systemic acquired resistance. New research has also uncovered additional layers of complexity surrounding NLR immune receptor activation, cooperation and sub-cellular localizations. Taken together, these recent advances bring us closer to understanding the web of molecular interactions responsible for coordinating defense responses and ultimately resistance.

  12. Daphnia as a refuge for an antibiotic resistance gene in an experimental freshwater community.

    Science.gov (United States)

    Eckert, Ester M; Di Cesare, Andrea; Stenzel, Birgit; Fontaneto, Diego; Corno, Gianluca

    2016-11-15

    Mechanisms that enable the maintenance of antibiotic resistance genes in the environment are still greatly unknown. Here we show that the tetracycline resistance gene tet(A) is largely removed from the pelagic aquatic bacterial community through filter feeding by Daphnia obtusa while it becomes detectable within the microbiome of the daphniids themselves, where it was not present prior to the experiment. We moreover show that a multitude of Daphnia-associated bacterial taxa are potential carriers of tet(A) and postulated that the biofilm-like structures, where bacteria grow in, may enable horizontal transfer of such genes. This experiment highlights the need to take ecological interactions and a broad range of niches into consideration when studying and discussing the fate of antibiotic resistance genes in nature.

  13. Metagenomics and other Methods for Measuring Antibiotic Resistance in Agroecosystems

    Science.gov (United States)

    Background: There is broad concern regarding antibiotic resistance on farms and in fields, however there is no standard method for defining or measuring antibiotic resistance in environmental samples. Methods: We used metagenomic, culture-based, and molecular methods to characterize the amount, t...

  14. Transmission of antibiotic resistance from animals to humans

    NARCIS (Netherlands)

    Huijbers, P.M.C.

    2016-01-01

    Huijbers, P.M.C. (2016). Transmission of antibiotic resistance from animals to humans: Broilers as a reservoir of ESBL-producing bacteria. PhD thesis, Wageningen University, Wageningen, the Netherlands. Antibiotic resistance in animals becomes a public health issue when there is transmission of anti

  15. Fighting antibiotic resistance in the intensive care unit using antibiotics

    NARCIS (Netherlands)

    Plantinga, Nienke L.; Wittekamp, Bastiaan H J; Van Duijn, Pleun J.; Bonten, Marc J M

    2015-01-01

    Antibiotic resistance is a global and increasing problem that is not counterbalanced by the development of new therapeutic agents. The prevalence of antibiotic resistance is especially high in intensive care units with frequently reported outbreaks of multidrug-resistant organisms. In addition to cl

  16. 544例急性腹泻门诊病例粪便的细菌菌谱及药敏分析%Analysis bacterial culture,identification and antibiotics resistance of 544 stools specimens of acute diarrhea outpatients

    Institute of Scientific and Technical Information of China (English)

    杨焕章; 严育忠; 范慧清; 徐英

    2015-01-01

    Objective To investigate the bacterial spectrum and antimicrobial resistance of pathogens isolated from stool of acute diarrhea outpatients ,and provide scientific evidence for clinic rational use of antibiotics .Methods Bacteria was detected by conven‐tional feces culture method ,including separation and biochemistry appraisal sure strains .The predominant bacteria were conducted antimicrobial resistance testing in acute diarrhea outpatients .Results 544 stool specimens were collected from acute diarrhea outpa‐tients from January 2011 to December 2012 .The total positive rate was 17 .83% .Positive rates of Escherichia coli ,Salmonella , Campylobacter ,Vibrio parahaemolyticus ,Other Aeromonas ,Shiga Plesiomonas ,Shigella and Aeromonas hydrophila were 4 .78% ,3 .68% ,2 .57% and 2 .39% ,1 .84% ,1 .28% ,0 .92% and 0 .37% ,respectively .Salmonella ,Campylobacter and Vibrio parahaemolyticus were susceptible to Ofloxacin ,Amoxicillin ,Ceftazidime .They were different resistance to conventional antibiot‐ics ,which were commonly used by clinic ,and the most serious resistance are ampicillin and nalidixic acid .Conclusion Escherichia coli ,Salmonella ,Campylobacter and Vibrio parahaemolyticus are predominant bacteria pathogens .It is important to better under‐stand pathogens spectrum and antimicrobial resistance of bacteria for controlling infection in acute diarrhea outpatients .%目的:了解急性腹泻患者粪便细菌菌群分布及其抗菌药物耐药情况,为临床合理使用抗菌药物提供科学依据。方法对该院2011年1月至2012年12月544例肠道门诊患者的粪便标本进行分离鉴定和药物敏感试验。结果544份粪便标本共分离到97株致病菌,总检出率为17.83%,其中致泻性大肠埃希氏菌属、非伤寒沙门氏菌属、弯曲菌属、副溶血性弧菌、其他气单胞菌、类志贺邻单胞菌、志贺氏菌属和嗜水气单胞菌的检出率分别为4.78%、3.68%、2.57%、2.39

  17. Bats as reservoir hosts of human bacterial pathogen, Bartonella mayotimonensis.

    Science.gov (United States)

    Veikkolainen, Ville; Vesterinen, Eero J; Lilley, Thomas M; Pulliainen, Arto T

    2014-06-01

    A plethora of pathogenic viruses colonize bats. However, bat bacterial flora and its zoonotic threat remain ill defined. In a study initially conducted as a quantitative metagenomic analysis of the fecal bacterial flora of the Daubenton's bat in Finland, we unexpectedly detected DNA of several hemotrophic and ectoparasite-transmitted bacterial genera, including Bartonella. Bartonella spp. also were either detected or isolated from the peripheral blood of Daubenton's, northern, and whiskered bats and were detected in the ectoparasites of Daubenton's, northern, and Brandt's bats. The blood isolates belong to the Candidatus-status species B. mayotimonensis, a recently identified etiologic agent of endocarditis in humans, and a new Bartonella species (B. naantaliensis sp. nov.). Phylogenetic analysis of bat-colonizing Bartonella spp. throughout the world demonstrates a distinct B. mayotimonensis cluster in the Northern Hemisphere. The findings of this field study highlight bats as potent reservoirs of human bacterial pathogens.

  18. Biology of Acinetobacter baumannii: Pathogenesis, Antibiotic Resistance Mechanisms, and Prospective Treatment Options

    Science.gov (United States)

    Lee, Chang-Ro; Lee, Jung Hun; Park, Moonhee; Park, Kwang Seung; Bae, Il Kwon; Kim, Young Bae; Cha, Chang-Jun; Jeong, Byeong Chul; Lee, Sang Hee

    2017-01-01

    Acinetobacter baumannii is undoubtedly one of the most successful pathogens responsible for hospital-acquired nosocomial infections in the modern healthcare system. Due to the prevalence of infections and outbreaks caused by multi-drug resistant A. baumannii, few antibiotics are effective for treating infections caused by this pathogen. To overcome this problem, knowledge of the pathogenesis and antibiotic resistance mechanisms of A. baumannii is important. In this review, we summarize current studies on the virulence factors that contribute to A. baumannii pathogenesis, including porins, capsular polysaccharides, lipopolysaccharides, phospholipases, outer membrane vesicles, metal acquisition systems, and protein secretion systems. Mechanisms of antibiotic resistance of this organism, including acquirement of β-lactamases, up-regulation of multidrug efflux pumps, modification of aminoglycosides, permeability defects, and alteration of target sites, are also discussed. Lastly, novel prospective treatment options for infections caused by multi-drug resistant A. baumannii are summarized. PMID:28348979

  19. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms.

    Science.gov (United States)

    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.

  20. Analysis of Romanian Bacteroides isolates for antibiotic resistance levels and the corresponding antibiotic resistance genes.

    Science.gov (United States)

    Székely, Edit; Eitel, Zsuzsa; Molnár, Szabolcs; Szász, Izabella Éva; Bilca, Doina; Sóki, József

    2015-02-01

    As part of an ESCMID Study Group on Anaerobic Infections (ESGAI) project, a study was conducted to measure the antibiotic susceptibilities and corresponding gene contents of 53 Bacteroides fragilis group strains isolated in Romania. The antibiotic resistance data was comparable with the data found for other East-European countries. Here, no resistant isolate was found for imipenem, metronidazole and tigecycline. An increasing role of the cepA, cfxA and cfiA genes was observed in their corresponding antibiotic resistances. Moreover, no isolate was found that harbored the cfiA gene with a possible activating IS element. Clindamycin resistance was low, similarly to that the rate for the ermF gene. However, we did find some isolates with nimB, ermB, msrSA, linA, satG, tetX, tetM and bexA genes. This study was the first to provide antibiotic resistance data for clinical Bacteroides strains from Romania.

  1. Occurrence and Antibiotic Resistance of Mesophilic Aeromonas in Three Riverine Freshwaters of Marrakech, Morocco

    OpenAIRE

    2001-01-01

    I n order to evaluate the impact of pollution and sewage on the occurrence and antibiotic resistance of mesophilic aeromonads in riverine freshwaters of Marrakech, samples were collected from three rivers (Oukaimeden, Ourika, and Tensift) upstream and downstream from the principal bordering villages. During a 2-year study, indicators of pollution increased dramatically in the downstream waters. Bacterial indicators (faecal coliforms and faecal streptococci) correlated wit...

  2. Functional characterization of the antibiotic resistance reservoir in the human microflora

    OpenAIRE

    Sommer, Morten O. A.; Dantas, Gautam; Church, George M.

    2009-01-01

    To understand the process by which antibiotic resistance genes are acquired by human pathogens, we functionally characterized the resistance reservoir in the microbial flora of healthy individuals. Most of the resistance genes we identified using culture independent sampling have not been previously identified and are evolutionarily distant from known resistance genes. By contrast, nearly half of the resistance genes we identified in cultured aerobic gut isolates (a small subset of the gut mi...

  3. Dynamics of bacterial diversity and antibiotic resistance of Escherichia coli in Fu River, Chengdu%成都府河水体细菌动态变化及耐药性

    Institute of Scientific and Technical Information of China (English)

    黎丽雯; 邹立扣; 周杨; 胡苏; 庞玉娟

    2012-01-01

    To analyze the water quality of the Fu River, nine sampling sites were chosen from Baopingkou site in Dujiangyan to Wangjiang Park site in Fu River. Three microbiological indexes, including total number of bacteria, total coliform and the number of fecal coliform, have been selected to evaluate the water quality, analyze seasonal factors and find out the contamination sources in two different seasons. Besides, taking the antibiotic resistance rate of Escherichia coli at Baopingkou as background, 102 E. Coli identified by morphology and 16S rDNA have been selected for following antimicrobial susceptibility testing, and the susceptibility has been performed according to the standard disk diffusion K-B method. The results show that though the total number of bacteria, total coliform and fecal coliform varied from Baopingkou, Dujiangyan to Wangjiang Park, the total number of bacteria shows an increasing trend as the water flows. The nutrients enrich in spring and summer, and water quality decrease. The susceptibility of 13 antimicrobial agents tested against E. Coli isolated shows that 0.96% - 33.33% of the isolates are resistant to B-lactam, 1. 39% -7.84% to aminoglycoside, 11.43% -11.76% to fluoroquinolone, and 52.78% to trimethoprim-sulfamethoxazole. The resistance to B-lactam and fluoroquinolone is related with the source of water, however, other resistances are in connection with polluted water discharged from hospital and residential areas. Generally, this study has provided theoretical foundation for the control of pollution in Fu River.%将府河从都江堰宝瓶口段至望江公园段分设9个监测点,在秋冬、春夏两季分别取水,首次建立由细菌总数、总大肠菌群数及粪大肠菌群数三个微生物学指标组成的体系,对府河两季水质进行对比监测分析,以综合评价水质、分析季节影响因素并反映出污染物来源.以都江堰宝瓶口大肠杆菌耐药率作为背景值,对整个河段的9个采

  4. IDENTIFICATION AND ANTIBIOTIC RESISTANCE PROFILE OFENTEROBACTERIACEAE SPECIES AND LACTOBACILLUS SPP. ISOLATED FROM HONEY BEES (APIS MELLIFERA DIGESTIVE TRACT

    Directory of Open Access Journals (Sweden)

    Lukáš Hleba

    2014-02-01

    Full Text Available Honey bees play important role in agricultural environment as main pollinators. Its important for many agricultural and wild plants. Also honey bee are producers of honey, which is consumed directly and it should be not a heat treatment. Many bacteria can be survive in honey for long time. Some of these bacteria are human and animal facultative pathogens, including Enterobactericaeae genera. If these bacteria contain antibiotic resistant genes than it can to leads to troubles in healing of some of bacterial infections. Lactobacillus spp. can be a reservoir of resistant genes for pathogenic bacterial strains. In this study we isolated Enterobacteriaceae strains from digestive tracts of honey bees. These strains was tested to the eight selected antibiotics by disc diffusion method and strains were indentified by MALDI TOF MS Biotyper. From this study we determined resistance to piperacillin in the highest level. Equally, we determined that Citrobacter gillenii was resistant to three antibiotics (piperacillin, chloramphenicol and levofloxacin from eight. Resistance to other antibiotics were determined in low levels and other indentified bacteria were resistant to one antibiotic, if any. Also we detected resistance in Lactobacillus spp. and determined MICs distribution for some selected antibiotics. For absence of similar studies we could not to discuss our results and we think that further experiments and studies are needed.

  5. Novel Conserved Genotypes Correspond to Antibiotic Resistance Phenotypes of E. coli Clinical Isolates.

    Directory of Open Access Journals (Sweden)

    Michelle C Swick

    Full Text Available Current efforts to understand antibiotic resistance on the whole genome scale tend to focus on known genes even as high throughput sequencing strategies uncover novel mechanisms. To identify genomic variations associated with antibiotic resistance, we employed a modified genome-wide association study; we sequenced genomic DNA from pools of E. coli clinical isolates with similar antibiotic resistance phenotypes using SOLiD technology to uncover single nucleotide polymorphisms (SNPs unanimously conserved in each pool. The multidrug-resistant pools were genotypically similar to SMS-3-5, a previously sequenced multidrug-resistant isolate from a polluted environment. The similarity was evenly spread across the entire genome and not limited to plasmid or pathogenicity island loci. Among the pools of clinical isolates, genomic variation was concentrated adjacent to previously reported inversion and duplication differences between the SMS-3-5 isolate and the drug-susceptible laboratory strain, DH10B. SNPs that result in non-synonymous changes in gyrA (encoding the well-known S83L allele associated with fluoroquinolone resistance, mutM, ligB, and recG were unanimously conserved in every fluoroquinolone-resistant pool. Alleles of the latter three genes are tightly linked among most sequenced E. coli genomes, and had not been implicated in antibiotic resistance previously. The changes in these genes map to amino acid positions in alpha helices that are involved in DNA binding. Plasmid-encoded complementation of null strains with either allelic variant of mutM or ligB resulted in variable responses to ultraviolet light or hydrogen peroxide treatment as markers of induced DNA damage, indicating their importance in DNA metabolism and revealing a potential mechanism for fluoroquinolone resistance. Our approach uncovered evidence that additional DNA binding enzymes may contribute to fluoroquinolone resistance and further implicate environmental bacteria as a

  6. The Antibiotic Resistance ‘Mobilome’: searching for the link between environment and clinic.

    Directory of Open Access Journals (Sweden)

    Julie ePerry

    2013-05-01

    Full Text Available Antibiotic resistance is an ancient problem, owing to the co-evolution of antibiotic-producing and target organisms in the soil and other environments over millennia. The environmental ‘resistome’ is the collection of all genes that directly or indirectly contribute to antibiotic resistance. Many of these resistance determinants originate in antibiotic-producing organisms (where they serve to mediate self-immunity, while others become resistance determinants only when mobilized and over-expressed in non-native hosts (like plasmid-based β-lactamases. The modern environmental resistome is under selective pressure from human activities such as agriculture, which may influence the composition of the local resistome and lead to gene transfer events. Beyond the environment, we are challenged in the clinic by the rise in both frequency and diversity of antibiotic resistant pathogens. We assume that clinical resistance originated in the environment, but few examples of direct gene exchange between the environmental resistome and the clinical resistome have been documented. Strong evidence exists to suggest that clinical aminoglycoside and vancomycin resistance enzymes, the extended-spectrum β-lactamase CTX-M and the quinolone resistance gene Qnr have direct links to the environmental resistome. In this review, we highlight recent advances in our understanding of horizontal gene transfer of antibiotic resistance genes from the environment to the clinic. Improvements in sequencing technologies coupled with functional metagenomic studies have revealed previously underappreciated diversity in the environmental resistome, and also established novel genetic links to the clinic. Understanding mechanisms of gene exchange becomes vital in controlling the future dissemination of antibiotic resistance.

  7. Risk factors for antibiotic resistance in Campylobacter spp. isolated from raw poultry meat in Switzerland

    Directory of Open Access Journals (Sweden)

    Danuser Jürg

    2003-12-01

    Full Text Available Abstract Background The world-wide increase of foodborne infections with antibiotic resistant pathogens is of growing concern and is designated by the World Health Organization as an emerging public health problem. Thermophilic Campylobacter have been recognised as a major cause of foodborne bacterial gastrointestinal human infections in Switzerland and in many other countries throughout the world. Poultry meat is the most common source for foodborne cases caused by Campylobacter. Because all classes of antibiotics recommended for treatment of human campylobacteriosis are also used in veterinary medicine, in view of food safety, the resistance status of Campylobacter isolated from poultry meat is of special interest. Methods Raw poultry meat samples were collected throughout Switzerland and Liechtenstein at retail level and examined for Campylobacter spp. One strain from each Campylobacter-positive sample was selected for susceptibility testing with the disc diffusion and the E-test method. Risk factors associated with resistance to the tested antibiotics were analysed by multiple logistic regression. Results In total, 91 Campylobacter spp. strains were isolated from 415 raw poultry meat samples. Fifty-one strains (59% were sensitive to all tested antibiotics. Nineteen strains (22% were resistant to a single, nine strains to two antibiotics, and eight strains showed at least three antibiotic resistances. Resistance was observed most frequently to ciprofloxacin (28.7%, tetracycline (12.6%, sulphonamide (11.8%, and ampicillin (10.3%. One multiple resistant strain exhibited resistance to five antibiotics including ciprofloxacin, tetracycline, and erythromycin. These are the most important antibiotics for treatment of human campylobacteriosis. A significant risk factor associated with multiple resistance in Campylobacter was foreign meat production compared to Swiss meat production (odds ratio = 5.7. Conclusion Compared to the situation in other

  8. Kynetic resazurin assay (KRA) for bacterial quantification of foodborne pathogens

    Science.gov (United States)

    Arenas, Yaxal; Mandel, Arkady; Lilge, Lothar

    2012-03-01

    Fast detection of bacterial concentrations is important for the food industry and for healthcare. Early detection of infections and appropriate treatment is essential since, the delay of treatments for bacterial infections tends to be associated with higher mortality rates. In the food industry and in healthcare, standard procedures require the count of colony-forming units in order to quantify bacterial concentrations, however, this method is time consuming and reports require three days to be completed. An alternative is metabolic-colorimetric assays which provide time efficient in vitro bacterial concentrations. A colorimetric assay based on Resazurin was developed as a time kinetic assay (KRA) suitable for bacterial concentration measurements. An optimization was performed by finding excitation and emission wavelengths for fluorescent acquisition. A comparison of two non-related bacteria, foodborne pathogens Escherichia coli and Listeria monocytogenes, was performed in 96 well plates. A metabolic and clonogenic dependence was established for fluorescent kinetic signals.

  9. Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure

    Science.gov (United States)

    Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

    2016-07-01

    Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

  10. Studies of Antibiotic Resistance of Beta-Lactamase Bacteria under Different Nutrition Limitations at the Single-Cell Level.

    Science.gov (United States)

    Wang, Ying; Ran, Min; Wang, Jun; Ouyang, Qi; Luo, Chunxiong

    2015-01-01

    Drug resistance involves many biological processes, including cell growth, cell communication, and cell cooperation. In the last few decades, bacterial drug resistance studies have made substantial progress. However, a major limitation of the traditional resistance study still exists: most of the studies have concentrated on the average behavior of enormous amounts of cells rather than surveying single cells with different phenotypes or genotypes. Here, we report our study of beta-lactamase bacterial drug resistance in a well-designed microfluidic device, which allows us to conduct more controllable experiments, such as controlling the nutrient concentration, switching the culture media, performing parallel experiments, observing single cells, and acquiring time-lapse images. By using GFP as a beta-lactamase indicator and acquiring time-lapse images at the single-cell level, we observed correlations between the bacterial heterogeneous phenotypes and their behavior in different culture media. The feedback loop between the growth rate and the beta-lactamase production suggests that the beta-lactamase bacteria are more resistant in a rich medium than in a relatively poor medium. In the poorest medium, the proportion of dormant cells may increase, which causes a lower death rate in the same generation. Our work may contribute to assaying the antibiotic resistance of pathogenic bacteria in heterogeneous complex media.

  11. Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure.

    Science.gov (United States)

    Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

    2016-07-22

    Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

  12. Exploring the immediate and long-term impact on bacterial communities in soil amended with animal and urban organic waste fertilizers using pyrosequencing and screening for horizontal transfer of antibiotic resistance

    DEFF Research Database (Denmark)

    Riber, Leise; Poulsen, Pernille H. B.; Al-Soud, Waleed A.;

    2014-01-01

    We investigated immediate and long-term effects on bacterial populations of soil amended with cattle manure, sewage sludge or municipal solid waste compost in an ongoing agricultural field trial. Soils were sampled in weeks 0, 3, 9 and 29 after fertilizer application. Pseudomonas isolates were...... time. Seasonal changes seemed to prevail with decreasing bacterial richness in week 9 followed by a significant increase in week 29 (springtime). The Pseudomonas population richness seemed temporarily affected by fertilizer treatments, especially in sludge- and compost-amended soils. To explain...

  13. Bithionol blocks pathogenicity of bacterial toxins, ricin, and Zika virus

    Science.gov (United States)

    Disease pathways form overlapping networks, and hub proteins represent attractive targets for broad-spectrum drugs. Using bacterial toxins as a proof of concept, we describe a new approach of discovering broad-spectrum therapies capable of inhibiting host proteins that mediate multiple pathogenic pa...

  14. Mechanisms of antibiotic resistance of Enterobacteriaceae family representatives

    Directory of Open Access Journals (Sweden)

    K. R. Kotsyuba

    2014-04-01

    Full Text Available The paper deals with the basic medical scheme of antibiotics use for treatment of lesions caused by enterobacteria and mechanisms of resistance of Enterobacteriaceae to different classes of antibiotics. It is known that the main mechanisms of resistance to antibiotics are enzymatic inactivation, modification of the target, efflux, violation of conduct through the membrane and formation of metabolic shunt. The most common cases of resistance to beta-lactams among Enterobacteriaceae relate to production of plasmid and chromosomal beta-lactamases, violation of the permeability of the outer membrane, and modification of target penicillin binding proteins. Active release of antibiotics from the cell, or efflux, in Enterobacteriaceae is used for maintaining resistance to tetracyclines, macrolides, carbapenems. Genes of efflux system are localized on plasmids and contribute to rapid spreading among Enterobacteriaceae. Mutations are the basis of resistance to novobiocinum and rifampicinum. Enzymatic inactivation by modifying is typical for resistance to aminoglycosides. Three groups of enzymes are engaged in the process, by adding the molecule of acetic acid, phosphate or adenine. Joining of these groups is irreversible and leads to complete loss of biological activity of the antibiotic. Resistance to aminoglycosides appears also due to inhibition of drug penetration, that is associated with genetically determined mechanisms of electron transport through the membrane. Resistance to quinolones and fluoroquinolones is associated with the modification of topoisomerase II and IV which are targets of these groups of antibiotics. Resistance is possible as a result of changes in the structure of the target, breaching of penetration into the cell, and active release from the cell. The highest level of resistance is develope in the case of two- or three-stage mutations in one or the other, or both, subunits in different genes. At the same time, for breaching of

  15. The relationship between pneumococcal serotypes and antibiotic resistance.

    Science.gov (United States)

    Song, Jae-Hoon; Dagan, Ron; Klugman, Keith P; Fritzell, Bernard

    2012-04-05

    Streptococcus pneumoniae (SP) causes significant burden of disease, including invasive pneumococcal disease and noninvasive diseases such as pneumonia and acute otitis media. SP has at least 93 different capsular serotypes, with the various serotypes having different propensities for producing disease or developing antibiotic resistance. An increase in the prevalence of antibiotic-resistant SP serotypes has been observed globally. The objective of this paper was to examine the relationship between antibiotic resistance and SP serotypes, with a primary focus on studies published in the past 10 years. Changing trends in antibiotic resistance and serotype distribution during this time, including those before and after the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), were analyzed. Factors that influence the prevalence of antibiotic-resistant serotypes include antibiotic selection pressure, the use of PCV7, and the emergence and spread of antibiotic-resistant clones. The emergence of multidrug resistant serotype 19A is of particular concern. Antibiotic-resistant SP is a global problem that must be addressed through multiple strategies, including national vaccination programs, antibiotic control programs, and ongoing surveillance.

  16. Unraveling Plant Responses to Bacterial Pathogens through Proteomics

    Directory of Open Access Journals (Sweden)

    Tamara Zimaro

    2011-01-01

    Full Text Available Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens.

  17. Methods to classify bacterial pathogens in cystic fibrosis

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Nielsen, Xiaohui Chen; Johansen, Ulla;

    2011-01-01

    Many bacteria can be detected in CF sputum, pathogenic and commensal. Modified Koch's criteria for identification of established and emerging CF pathogens are therefore described. Methods are described to isolate bacteria and to detect bacterial biofilms in sputum or lung tissue from CF patients...... by means of conventional culturing and staining techniques and by the PNA FISH technique. Additionally, the confocal scanning laser microscopy technique is described for studying biofilms in vitro in a flow cell system. The recA-gene PCR and the RFLP-based identification methods are described...... for identification of isolates from the Burkholderia complex to the species level. DNA typing by PFGE, which can be used for any bacterial pathogen, is described as it is employed for Pseudomonas aeruginosa. A commercially available ELISA method is described for measuring IgG antibodies against P. aeruginosa in CF...

  18. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara

    2011-11-03

    Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

  19. A novel method to discover fluoroquinolone antibiotic resistance (qnr genes in fragmented nucleotide sequences

    Directory of Open Access Journals (Sweden)

    Boulund Fredrik

    2012-12-01

    Full Text Available Abstract Background Broad-spectrum fluoroquinolone antibiotics are central in modern health care and are used to treat and prevent a wide range of bacterial infections. The recently discovered qnr genes provide a mechanism of resistance with the potential to rapidly spread between bacteria using horizontal gene transfer. As for many antibiotic resistance genes present in pathogens today, qnr genes are hypothesized to originate from environmental bacteria. The vast amount of data generated by shotgun metagenomics can therefore be used to explore the diversity of qnr genes in more detail. Results In this paper we describe a new method to identify qnr genes in nucleotide sequence data. We show, using cross-validation, that the method has a high statistical power of correctly classifying sequences from novel classes of qnr genes, even for fragments as short as 100 nucleotides. Based on sequences from public repositories, the method was able to identify all previously reported plasmid-mediated qnr genes. In addition, several fragments from novel putative qnr genes were identified in metagenomes. The method was also able to annotate 39 chromosomal variants of which 11 have previously not been reported in literature. Conclusions The method described in this paper significantly improves the sensitivity and specificity of identification and annotation of qnr genes in nucleotide sequence data. The predicted novel putative qnr genes in the metagenomic data support the hypothesis of a large and uncharacterized diversity within this family of resistance genes in environmental bacterial communities. An implementation of the method is freely available at http://bioinformatics.math.chalmers.se/qnr/.

  20. Natural antimicrobial peptide complexes in the fighting of antibiotic resistant biofilms: Calliphora vicina medicinal maggots

    Science.gov (United States)

    Gordya, Natalia; Yakovlev, Andrey; Kruglikova, Anastasia; Tulin, Dmitry; Potolitsina, Evdokia; Suborova, Tatyana; Bordo, Domenico; Rosano, Camillo; Chernysh, Sergey

    2017-01-01

    Biofilms, sedimented microbial communities embedded in a biopolymer matrix cause vast majority of human bacterial infections and many severe complications such as chronic inflammatory diseases and cancer. Biofilms’ resistance to the host immunity and antibiotics makes this kind of infection particularly intractable. Antimicrobial peptides (AMPs) are a ubiquitous facet of innate immunity in animals. However, AMPs activity was studied mainly on planktonic bacteria and little is known about their effects on biofilms. We studied structure and anti-biofilm activity of AMP complex produced by the maggots of blowfly Calliphora vicina living in environments extremely contaminated by biofilm-forming germs. The complex exhibits strong cell killing and matrix destroying activity against human pathogenic antibiotic resistant Escherichia coli, Staphylococcus aureus and Acinetobacter baumannii biofilms as well as non-toxicity to human immune cells. The complex was found to contain AMPs from defensin, cecropin, diptericin and proline-rich peptide families simultaneously expressed in response to bacterial infection and encoded by hundreds mRNA isoforms. All the families combine cell killing and matrix destruction mechanisms, but the ratio of these effects and antibacterial activity spectrum are specific to each family. These molecules dramatically extend the list of known anti-biofilm AMPs. However, pharmacological development of the complex as a whole can provide significant advantages compared with a conventional one-component approach. In particular, a similar level of activity against biofilm and planktonic bacteria (MBEC/MIC ratio) provides the complex advantage over conventional antibiotics. Available methods of the complex in situ and in vitro biosynthesis make this idea practicable. PMID:28278280

  1. Reclaimed water as a reservoir of antibiotic resistance genes: distribution system and irrigation implications

    Directory of Open Access Journals (Sweden)

    Nicole L Fahrenfeld

    2013-05-01

    Full Text Available Treated wastewater is increasingly being reused to achieve sustainable water management in arid regions. The objective of this study was to quantify the distribution of antibiotic resistance genes (ARGs in recycled water, particularly after it has passed through the distribution system, and to consider point-of-use implications for soil irrigation. Three separate reclaimed wastewater distribution systems in the western U.S. were examined. Quantitative polymerase chain reaction (qPCR was used to quantify ARGs corresponding to resistance to sulfonamides (sul1, sul2, macrolides (ermF, tetracycline (tet(A, tet(O, glycopeptides (vanA, and methicillin (mecA, in addition to genes present in waterborne pathogens Legionella pneumophila (Lmip, Escherichia coli (gadAB, and Pseudomonas aeruginosa (ecfx, gyrB. In a parallel lab study, the effect of irrigating an agricultural soil with secondary, chlorinated, or dechlorinated wastewater effluent was examined in batch microcosms. A broader range of ARGs were detected after the reclaimed water passed through the distribution systems, highlighting the importance of considering bacterial re-growth and the overall water quality at the point of use. Screening for pathogens with qPCR indicated presence of Lmip and gadAB genes, but not ecfx or gyrB. In the lab study, chlorination was observed to reduce 16S rRNA and sul2 gene copies in the wastewater effluent, while dechlorination had no apparent effect. ARGs levels did not change with time in soil slurries incubated after a single irrigation event with any of the effluents. However, when irrigated repeatedly with secondary wastewater effluent (not chlorinated or dechlorinated, elevated levels of sul1 and sul2 were observed. This study suggests that reclaimed water may be an important reservoir of ARGs, especially at the point of use, and that attention should be directed towards the fate of ARGs in irrigation water and the implications for human health.

  2. Detection of virulence, antibiotic resistance and toxin (VAT) genes in Campylobacter species using newly developed multiplex PCR assays.

    Science.gov (United States)

    Laprade, Natacha; Cloutier, Michel; Lapen, David R; Topp, Edward; Wilkes, Graham; Villemur, Richard; Khan, Izhar U H

    2016-05-01

    Campylobacter species are one of the leading causes of bacterial gastroenteritis in humans worldwide. This twofold study was sought to: i) develop and optimize four single-tube multiplex PCR (mPCR) assays for the detection of six virulence (ciaB, dnaJ, flaA, flaB, pldA and racR), three toxin (cdtA, cdtB and cdtC) and one antibiotic resistance tet(O) genes in thermophilic Campylobacter spp. and ii) apply and evaluate the developed mPCR assays by testing 470 previously identified C. jejuni, C. coli and C. lari isolates from agricultural water. In each mPCR assay, a combination of two or three sets of primer pairs for virulence, antibiotic resistance and toxin (VAT) genes was used and optimized. Assay 1 was developed for the detection of dnaJ, racR and cdtC genes with expected amplification sizes of 720, 584 and 182bp. Assay 2 generated PCR amplicons for tet(O) and cdtA genes of 559 and 370bp. Assay 3 amplified cdtB ciaB, and pldA genes with PCR amplicon sizes of 620, 527 and 385bp. Assay 4 was optimized for flaA and flaB genes that generated PCR amplicons of 855 and 260bp. The primer pairs and optimized PCR protocols did not show interference and/or cross-amplification with each other and generated the expected size of amplification products for each target VAT gene for the C. jejuni ATCC 33291 reference strain. Overall, all ten target VAT genes were detected at a variable frequency in tested isolates of thermophilic Campylobacter spp. where cdtC, flaB, ciaB, cdtB, cdtA and pldA were commonly detected compared to the flaA, racR, dnaJ and tet(O) genes which were detected with less frequency. The developed mPCR assays are simple, rapid, reliable and sensitive tools for simultaneously assessing potential pathogenicity and antibiotic resistance profiling in thermophilic Campylobacter spp. The mPCR assays will be useful in diagnostic and analytical settings for routine screening of VAT characteristics of Campylobacter spp. as well as being applicable in epidemiological

  3. The negative impact of antibiotic resistance.

    Science.gov (United States)

    Friedman, N D; Temkin, E; Carmeli, Y

    2016-05-01

    Antibacterial therapy is one of the most important medical developments of the twentieth century; however, the spread of resistance in healthcare settings and in the community threatens the enormous gains made by the availability of antibiotic therapy. Infections caused by resistant bacteria lead to up to two-fold higher rates of adverse outcomes compared with similar infections caused by susceptible strains. These adverse outcomes may be clinical or economic and reflect primarily the failure or delay of antibiotic treatment. The magnitude of these adverse outcomes will be more pronounced as disease severity, strain virulence, or host vulnerability increases. The negative impacts of antibacterial resistance can be measured at the patient level by increased morbidity and mortality, at the healthcare level by increased resource utilization, higher costs and reduced hospital activity and at the society level by antibiotic treatment guidelines favouring increasingly broad-spectrum empiric therapy. In this review we will discuss the negative impact of antibiotic resistance on patients, the healthcare system and society.

  4. 深圳儿童医院2010年常见病原菌分布及耐药性调查%Antibiotic-resistance and Distribution of Nosocomial Infection Pathogens among Children Patients in Shenzhen Children's Hospital

    Institute of Scientific and Technical Information of China (English)

    胡瑛; 文飞球; 钟春梅; 王红梅

    2011-01-01

    目的:了解医院常见病原菌及其耐药情况,为临床用药提供参考.方法:对深圳市儿童医院2010年1月 ~12月住院患儿检出的病原菌分布及耐药情况进行回顾性分析.结果:共检出常见病原菌3 629株,其中革兰阴性 (G-) 菌 2 493株,占68 7%,革兰阳性(G+)菌1 136株,占31.3%.G-杆菌以肺炎克雷伯菌(22.7%)、大肠埃希菌(20.4%)、鲍曼不动杆菌(10 7%)等为主,肺炎克雷伯菌和大肠埃希菌产ESBLs率分别是41.3%和51.7%;G+ 球菌中MRSA检出率为15.5%.G- 杆菌对碳青霉烯类及酶抑制剂表现出较高的药物敏感性,对氨基青霉素类耐药性高;G+菌未检出碳青霉烯类、安沙霉素类、磷霉素类、糖肽类及链阳霉素类药物的耐药菌株,对青霉素G耐药率高达93.5%.结论:本地区儿童感染疾病以下呼吸道感染为主,病原菌以肠杆菌科细菌及葡萄球菌为主,对碳青霉烯类(亚胺培南)和糖肽类抗生素(万古霉素)仍保持高度的药物敏感性.%Objective: To understand the main pathogens of nosocomial infection and analyze its distribution as well as its drug resistance, then to find an effective way to deal with such pathogens. Methods: Made a retrospective investigation on the clinical data of hospitalized patients who stayed in Shenzhen Children's Hospital during January to December 2010. Results: It appeared 3,629 cases, among which there were 2,493 Gram-negative strains (took up 68.7% ), while Gram-positive were 1,136 strains ( took up 31.3% ). The main pathogens were Klebsiella pnenmoniae (22.7%), Escherichia coli (20.4%), and Acinetobacter banmanii (10.7%) among gram negative bacteria. The ESBLs-prodncing rates of Escherichia coli and Klebsiella pnenmoniae were 51.7% and 41.3% while MRSA in gram positive coccus was 15.5%. Gram-negative pathogens showed high rates of chug-sensitivity on carbapenem and enzyme inhibitors, and gram-positive pathogens showed 93.5% drug resistance to penicillin. No resistant strains to

  5. 重视细菌生物被膜导致的细菌耐药及其解决方案%Attention to the antibiotic resistance caused by bacterial biofilm and its solutions

    Institute of Scientific and Technical Information of China (English)

    伍勇; 陈丽华

    2014-01-01

    生物被膜的形成使细菌获得了以多细胞生存的生命形式。与浮游菌相比,生物被膜状态下细菌的耐药性显著增强。细菌生物被膜形成是许多亚急性和慢性感染病理过程的一个关键步骤,在临床上可以形成细菌生物被膜病和生物材料相关感染,已成为临床医疗工作的重点和难点。了解细菌生物被膜的耐药机制是提供解决方案的关键。(中华检验医学杂志,2014,37:725-727)%Biofilm formation makes bacteria adopt a multicellular lifestyle.Compared to planktonic cells, biofilm-grown cells express an increased resistance to antimicrobial agents.Bacterial biofilm formation is a crucial step in the pathogenesis of many subacute and chronic bacterial infections.In clinical setting, biofilm can cause bacterial biofilm disease and biomaterial associated infection.Understanding the mechanisms involved in biofilm-associated antimicrobial resistance is key to the development of new solutions.

  6. Pervasive selection for and against antibiotic resistance in inhomogeneous multistress environments.

    Science.gov (United States)

    Chait, Remy; Palmer, Adam C; Yelin, Idan; Kishony, Roy

    2016-01-20

    Antibiotic-sensitive and -resistant bacteria coexist in natural environments with low, if detectable, antibiotic concentrations. Except possibly around localized antibiotic sources, where resistance can provide a strong advantage, bacterial fitness is dominated by stresses unaffected by resistance to the antibiotic. How do such mixed and heterogeneous conditions influence the selective advantage or disadvantage of antibiotic resistance? Here we find that sub-inhibitory levels of tetracyclines potentiate selection for or against tetracycline resistance around localized sources of almost any toxin or stress. Furthermore, certain stresses generate alternating rings of selection for and against resistance around a localized source of the antibiotic. In these conditions, localized antibiotic sources, even at high strengths, can actually produce a net selection against resistance to the antibiotic. Our results show that interactions between the effects of an antibiotic and other stresses in inhomogeneous environments can generate pervasive, complex patterns of selection both for and against antibiotic resistance.

  7. Distinction between the Cfr Methyltransferase Conferring Antibiotic Resistance and the Housekeeping RlmN Methyltransferase

    DEFF Research Database (Denmark)

    Atkinson, Gemma C; Hansen, Lykke H; Tenson, Tanel

    2013-01-01

    The cfr gene encodes the Cfr methyltransferase that primarily methylates C-8 in A2503 of 23S rRNA in the peptidyl transferase region of bacterial ribosomes. The methylation provides resistance to six classes of antibiotics of clinical and veterinary importance. The rlmN gene encodes the Rlm......N methyltransferase that methylates C-2 in A2503 in 23S rRNA and A37 in tRNA, but RlmN does not significantly influence antibiotic resistance. The enzymes are homologous and use the same mechanism involving radical S-adenosyl methionine to methylate RNA via an intermediate involving a methylated cysteine....... The differentiation between the two classes is supported by previous and new experimental evidence from antibiotic resistance, primer extensions, and mass spectrometry. Finally, evolutionary aspects of the distribution of Cfr- and RlmN-like enzymes are discussed....

  8. Unraveling the genetic driving forces enabling antibiotic resistance at the single cell level

    Science.gov (United States)

    Bos, Julia

    Bacteria are champions at finding ways to quickly respond and adapt to environments like the human gut, known as the epicentre of antibiotic resistance. How do they do it? Combining molecular biology tools to microfluidic and fluorescence microscopy technologies, we monitor the behavior of bacteria at the single cell level in the presence of non-toxic doses of antibiotics. By tracking the chromosome dynamics of Escherichia coli cells upon antibiotic treatment, we examine the changes in the number, localization and content of the chromosome copies within one cell compartment or between adjacent cells. I will discuss how our work pictures the bacterial genomic plasticity as a driving force in evolution and how it provides access to the mechanisms controlling the subtle balance between genetic diversity and stability in the development of antibiotic resistance.

  9. Prevalence and antibiotic resistance of commensal Streptococcus pneumoniae in nine European countries.

    Science.gov (United States)

    Yahiaoui, Rachid Y; den Heijer, Casper Dj; van Bijnen, Evelien Me; Paget, W John; Pringle, Mike; Goossens, Herman; Bruggeman, Cathrien A; Schellevis, François G; Stobberingh, Ellen E

    2016-06-01

    The human microbiota represents an important reservoir of antibiotic resistance. Moreover, the majority of antibiotics are prescribed in primary care. For this reason, we assessed the prevalence and antibiotic resistance of nasal carriage strains of Streptococcus pneumoniae, the most prevalent bacterial causative agent of community-acquired respiratory tract infections, in outpatients in nine European countries. Nasal swabs were collected between October 2010 and May 2011, from 32,770 patients, recruited by general practices in nine European countries. Overall prevalence of S. pneumoniae nasal carriage in the nine countries was 2.9%. The carriage was higher in men (3.7%) than in women (2.7%). Children (4-9 years) had a higher carriage prevalence (27.2%) compared with those older than 10 years (1.9%). The highest resistance observed was to cefaclor. The highest prevalence of multidrug resistance was found in Spain and the lowest prevalence was observed in Sweden.

  10. 湖南省即食食品中食源性致病菌污染状况及耐药性研究%Contamination Status of Food Borne Pathogenic Bacteria in Instant Food in Hunan and Their Antibiotic Resistance

    Institute of Scientific and Technical Information of China (English)

    贾华云; 王岚; 胡旃; 刘建琪; 张林青; 张红

    2013-01-01

    目的 了解湖南地区即食食品中食源性致病菌的污染状况和耐药性,为预防和控制食源性疾病提供科学依据. 方法 从湖南地区的农贸市场、超市和餐饮单位采集即食食品(凉拌菜和熟肉制品),依据GB 4789-2010和GB/T 4789-2008方法,对样品进行沙门菌等4种食源性致病菌检测,分离菌株使用微量肉汤稀释法进行药敏试验. 结果 991份样品共检出食源性致病菌92株,检出率为9.28%,其中检出金黄色葡萄球菌68株,检出率为6.86%,检出沙门菌和单增李斯特菌各12株,检出率为1.21%,未检出大肠埃希菌O157.药敏结果显示金黄色葡萄球菌和沙门菌均具有一定的耐药性,其中金黄色葡萄球菌对苯唑西林的耐药率高达61.76%,而且多重耐药明显. 结论 湖南地区即食食品存在一定的食源性致病菌污染,应加大卫生监督力度,防止食源性疾病的暴发流行;同时应控制动物饲料中抗生素的添加使用,加强抗生素的管理和耐药性监测.%Objective To investigate the contamination status of food borne pathogenic bacteria in instant food in Hunan and to test their antibiotic resistance, so as to provide evidence for the prevention and control of food borne diseases. Methods Salad and cooked meat were collected in food produce markets, supermarkets and catering units in Hunan province. Four food borne pathogenic bacteria including Salmonella in food were identified in accordance with GB 4789 - 2010 and GB/T 4789 -2008. The bacteria were isolated by broth dilution technique to test their drug sensitivity. Results Totally, 92 strains of food borne pathogenic bacteria were identified in 991 food samples, with an incidence of 9.28% . The detection rate of Staphylococcus aureus was 6.86% (68/991). The detection rates of Salmonella and Listeria monocytogenes were both 1.21% (12/991). Es-cherichia coli O157 was not detected. The drug sensitivity test indicated that Staphylococcus aureus and

  11. Geriatrics nosocomial pulmonary infection bacterial distribution and antibiotic resistance analysis%老年病科院内肺部感染细菌分布及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    贾巧; 杜万红

    2013-01-01

    Objective To analyze the Department of Geriatrics, acquired pulmonary infections of bacterial distribution and drug resistance, provide the basis for the clinical application of antibiotic treatment. Methods Geriatrics nosocomial pulmonary infection in the separation of bacterial strains, the resistance of fungal strains to investigate. Results G-bacteria mainly the results of hospital-acquired infections still accounted for 73.3%, fol-lowed by G+bacteria 17.9%, fungi 8.7%. In the bacterial infections, G-bacteria accounted for 80.3%of G+bacteria accounted for 19.7%. G-bacteria is still Pseudomonas aeruginosa, accounting for 21.7%. G+bacteria Staphylococ-cus aureus 31.4%. Drug resistance, bacterial resistance to serious fungal resistance lighter. Conclusions of bacte-rial resistance to commonly used antibiotics, and there was the multi-drug resistant. Should strictly adhere to the principle of the use of antibiotics, use of antibiotics based on susceptibility.%  目的:分析老年病科院内获得性肺部感染的细菌的分布及其耐药性,为临床合理应用抗生素治疗提供依据。方法:对老年病科院内肺部感染的所有分离的细菌菌株、真菌菌株的耐药性进行调查。结果:医院获得性感染中仍以G-菌为主占73.3%,其次为G+菌17.9%,真菌8.7%。在细菌感染中,G-菌占80.3%,G+菌占19.7%。 G-菌仍以铜绿假单胞菌为主,占21.7%。 G+菌以金黄色葡萄球菌为主31.4%。耐药性方面,细菌耐药性严重,真菌耐药性较轻。结论:细菌对常用抗生素的耐药性严重,且呈多重耐药。应严格掌握抗生素使用原则,根据药敏选用抗生素。

  12. Population structure of Neisseria gonorrhoeae based on whole genome data and its relationship with antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Matthew N. Ezewudo

    2015-03-01

    Full Text Available Neisseria gonorrhoeae is the causative agent of gonorrhea, a sexually transmitted infection (STI of major importance. As a result of antibiotic resistance, there are now limited options for treating patients. We collected draft genome sequence data and associated metadata data on 76 N. gonorrhoeae strains from around the globe and searched for known determinants of antibiotics resistance within the strains. The population structure and evolutionary forces within the pathogen population were analyzed. Our results indicated a cosmopolitan gonoccocal population mainly made up of five subgroups. The estimated ratio of recombination to mutation (r/m = 2.2 from our data set indicates an appreciable level of recombination occurring in the population. Strains with resistance phenotypes to more recent antibiotics (azithromycin and cefixime were mostly found in two of the five population subgroups.

  13. Insights into novel antimicrobial compounds and antibiotic resistance genes from soil metagenomes

    Directory of Open Access Journals (Sweden)

    Alinne P Castro

    2014-09-01

    Full Text Available In recent years a major worldwide problem has arisen with regard to infectious diseases caused by resistant bacteria. Resistant pathogens are related to high mortality and also to enormous healthcare costs. In this field, cultured microorganisms have been commonly focused in attempts to isolate antibiotic resistance genes or to identify antimicrobial compounds. Although this strategy has been successful in many cases, most of the microbial diversity and related antimicrobial molecules have been completely lost. As an alternative, metagenomics has been used as a reliable approach to reveal the prospective reservoir of antimicrobial compounds and antibiotic resistance genes in the uncultured microbial community that inhabits a number of environments. In this context, this review will focus on resistance genes as well as on novel antibiotics revealed by a metagenomics approach from the soil environment. Biotechnology prospects are also discussed, opening new frontiers for antibiotic development.

  14. Antibiotic sensitivity profile of bacterial pathogens in postoperative wound infections at a tertiary care hospital in Gujarat, India

    Directory of Open Access Journals (Sweden)

    Nutanbala N Goswami

    2011-01-01

    Full Text Available Objective: To find out the most common bacterial pathogens responsible for post-operative wound infection and their antibiotic sensitivity profile. Materials and Methods: This prospective, observational study was carried out in patients of postoperative wound infection. Samples from wound discharge were collected using a sterile swab and studied for identification of isolates by Gram stains and culture growth followed by in vitro antibiotic susceptibility testing performed by disc diffusion method on Mueller Hinton agar. Results: Out of 183 organisms, 126 (68.85% isolated organisms were gram negative. Staphylococcus aureus, 48 (26.23%, was the predominant organism. S. aureus was sensitive to rifampicin (89.58%, levofloxacin (60.42%, and vancomycin (54.17%. Pseudomonas aeruginosa was sensitive to ciprofloxacin (83.78%, gatifloxacin (51.35%, and meropenem (51.35%. Escherichia coli was sensitive to levofloxacin (72.41% and ciprofloxacin (62.07%. Klebsiella pneumoniae was sensitive to ciprofloxacin (63.16%, levofloxacin (63.16%, gatifloxacin (63.16%, and linezolid (56.52%. Proteus mirabilis was sensitive to ciprofloxacin (75% and linezolid (62.50. Proteus vulgaris was sensitive to ampicillin+sulbactam (57.14% followed by levofloxacin (50%. Conclusions: There is an alarming increase of infections caused by antibiotic-resistant bacteria, particularly in the emergence of VRSA/VISA, meropenem, and third generation cephalosporin resistant Pseudomonas aeruginosa. Linezolid showing sensitivity against Gram negative bacteria.

  15. Characterization of Antibiotic Resistance Gene Abundance and Microbiota Composition in Feces of Organic and Conventional Pigs from Four EU Countries

    DEFF Research Database (Denmark)

    Gerzova, Lenka; Babak, Vladimir; Sedlar, Karel

    2015-01-01

    natural lifestyle implies their increased exposure to environmental sources of different microorganisms including pathogens. To address these concerns, we determined the abundance of antibiotic resistance and diversity within fecal microbiota in pigs kept under conventional and organic farming systems...... in Sweden, Denmark, France and Italy. The abundance of sul1, sul2, strA, tet(A), tet(B) and cat antibiotic resistance genes was determined in 468 samples by real-time PCR and the fecal microbiota diversity was characterized in 48 selected samples by pyrosequencing of V3/V4 regions of 16S rRNA. Contrary...... to our expectations, there were no extensive differences between the abundance of tested antibiotic resistance genes in microbiota originating from organic or conventionally housed pigs within individual countries. There were also no differences in the microbiota composition of organic and conventional...

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

    Science.gov (United States)

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

    2016-01-01

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

  17. The Structure of Fitness Landscapes in Antibiotic-Resistant Bacteria

    Science.gov (United States)

    Deris, Barrett; Kim, Minsu; Zhang, Zhongge; Okano, Hiroyuki; Hermsen, Rutger; Gore, Jeff; Hwa, Terence

    2014-03-01

    To predict the emergence of antibiotic resistance, quantitative relations must be established between the fitness of drug-resistant organisms and the molecular mechanisms conferring resistance. We have investigated E. coli strains expressing resistance to translation-inhibiting antibiotics. We show that resistance expression and drug inhibition are linked in a positive feedback loop arising from an innate, global effect of drug-inhibited growth on gene expression. This feedback leads generically to plateau-shaped fitness landscapes and concomitantly, for strains expressing at least moderate degrees of drug resistance, gives rise to an abrupt drop in growth rates of cultures at threshold drug concentrations. A simple quantitative model of bacterial growth based on this innate feedback accurately predicts experimental observations without ad hoc parameter fitting. We describe how drug-inhibited growth rate and the threshold drug concentration (the minimum inhibitory concentration, or MIC) depend on the few biochemical parameters that characterize the molecular details of growth inhibition and drug resistance (e.g., the drug-target dissociation constant). And finally, we discuss how these parameters can shape fitness landscapes to determine evolutionary dynamics and evolvability.

  18. Detection of foodborne bacterial pathogens from individual filth flies.

    Science.gov (United States)

    Pava-Ripoll, Monica; Pearson, Rachel E G; Miller, Amy K; Ziobro, George C

    2015-02-13

    There is unanimous consensus that insects are important vectors of foodborne pathogens. However, linking insects as vectors of the pathogen causing a particular foodborne illness outbreak has been challenging. This is because insects are not being aseptically collected as part of an environmental sampling program during foodborne outbreak investigations and because there is not a standardized method to detect foodborne bacteria from individual insects. To take a step towards solving this problem, we adapted a protocol from a commercially available PCR-based system that detects foodborne pathogens from food and environmental samples, to detect foodborne pathogens from individual flies.Using this standardized protocol, we surveyed 100 wild-caught flies for the presence of Cronobacter spp., Salmonella enterica, and Listeria monocytogenes and demonstrated that it was possible to detect and further isolate these pathogens from the body surface and the alimentary canal of a single fly. Twenty-two percent of the alimentary canals and 8% of the body surfaces from collected wild flies were positive for at least one of the three foodborne pathogens. The prevalence of Cronobacter spp. on either body part of the flies was statistically higher (19%) than the prevalence of S. enterica (7%) and L.monocytogenes (4%). No false positives were observed when detecting S. enterica and L. monocytogenes using this PCR-based system because pure bacterial cultures were obtained from all PCR-positive results. However, pure Cronobacter colonies were not obtained from about 50% of PCR-positive samples, suggesting that the PCR-based detection system for this pathogen cross-reacts with other Enterobacteriaceae present among the highly complex microbiota carried by wild flies. The standardized protocol presented here will allow laboratories to detect bacterial foodborne pathogens from aseptically collected insects, thereby giving public health officials another line of evidence to find out how

  19. Sponge microbiota are a reservoir of functional antibiotic resistance genes

    Directory of Open Access Journals (Sweden)

    Dennis Versluis

    2016-11-01

    Full Text Available Wide application of antibiotics has contributed to the evolution of multi-drug resistant human pathogens, resulting in poorer treatment outcomes for infections. In the marine environment, seawater samples have been investigated as a resistance reservoir; however, no studies have methodically examined sponges as a reservoir of antibiotic resistance. Sponges could be important in this respect because they often contain diverse microbial communities that have the capacity to produce bioactive metabolites. Here, we applied functional metagenomics to study the presence and diversity of functional resistance genes in the sponges Aplysina aerophoba, Petrosia ficiformis and Corticium candelabrum. We obtained 37 insert sequences facilitating resistance to D-cycloserine (n=6, gentamicin (n=1, amikacin (n=7, trimethoprim (n=17, chloramphenicol (n=1, rifampicin (n=2 and ampicillin (n=3. Fifteen of 37 inserts harboured resistance genes that shared <90% amino acid identity with known gene products, whereas on 13 inserts no resistance gene could be identified with high confidence, in which case we predicted resistance to be mainly mediated by antibiotic efflux. One marine-specific ampicillin-resistance-conferring β-lactamase was identified in the genus Pseudovibrio with 41% global amino acid identity to the closest β-lactamase with demonstrated functionality, and subsequently classified into a new family termed PSV. Taken together, our results show that sponge microbiota host diverse and novel resistance genes that may be harnessed by phylogenetically distinct bacteria.

  20. Antibiotic resistance: from Darwin to Lederberg to Keynes.

    Science.gov (United States)

    Amábile-Cuevas, Carlos F

    2013-04-01

    The emergence and spread of antibiotic-resistant bacteria reflects both, a gradual, completely Darwinian evolution, which mostly yields slight decreases in antibiotic susceptibility, along with phenotypes that are not precisely characterized as "resistance"; and sudden changes, from full susceptibility to full resistance, which are driven by a vast array of horizontal gene transfer mechanisms. Antibiotics select for more than just antibiotic resistance (i.e., increased virulence and enhanced gene exchange abilities); and many non-antibiotic agents or conditions select for or maintain antibiotic resistance traits as a result of a complex network of underlying and often overlapping mechanisms. Thus, the development of new antibiotics and thoughtful, integrated anti-infective strategies is needed to address the immediate and long-term threat of antibiotic resistance. Since the biology of resistance is complex, these new drugs and strategies will not come from free-market forces, or from "incentives" for pharmaceutical companies.

  1. Antibiotics and antibiotic resistance in agroecosystems: State of the science

    Science.gov (United States)

    This review article proposes a simple causal model depicting relationships involved in dissemination of antibiotics and antibiotic resistance in agroecosystems and potential effects on human health, functioning of natural ecosystems, and agricultural productivity. Available evidence for each causal ...

  2. Antibiotic Resistance Threats in the U.S.

    Science.gov (United States)

    ... What's this? Submit Button Past Emails CDC Features Antibiotic Resistance Threats in the US Recommend on Facebook Tweet Share Compartir Antibiotics are powerful tools for fighting illness and disease, ...

  3. Handling Time-dependent Variables : Antibiotics and Antibiotic Resistance

    NARCIS (Netherlands)

    Munoz-Price, L. Silvia; Frencken, Jos F.; Tarima, Sergey; Bonten, Marc

    2016-01-01

    Elucidating quantitative associations between antibiotic exposure and antibiotic resistance development is important. In the absence of randomized trials, observational studies are the next best alternative to derive such estimates. Yet, as antibiotics are prescribed for varying time periods, antibi

  4. CURRENT ISSUES REGARDING ENDOCRINE DISRUPTING CHEMICALS AND ANTIBIOTIC RESISTANCE

    Science.gov (United States)

    Recently public concern has increased regarding industrial and environmental substances that may have adverse hormonal effects in human and wildlife populations. This concern has also been expanded to include antibiotic-resistant bacteria and the presence of various antibiotics a...

  5. Antibiotic resistant urinary tract infections in an urology ward

    Directory of Open Access Journals (Sweden)

    A. Rădulescu

    2015-12-01

    Full Text Available Introduction: UTI (urinary tract infections represent a central pathology for a urological service. Antibiotic resistance is growing at a steady and alarming rate worldwide and especially in Romania. Method and materials: We have analyzed all the patients that were admitted to our clinic for continuous hospitalization between January 2015 and October 2015. All patients undergone urine culture and all cultures positive had an antibiogram worked up. We have selected all patients that had antibiotic resistance to at least an antibiotic. Results: From 1745 patients admitted for continuous hospitalization, we had 180 positive urine cultures at admission from which 125 had at least an antibiotic resistance. Conclusions: Antibiotic resistance is a serious phenomenon, with potential lethal complications, which we encounter daily in urological practice.

  6. Functional metagenomics for the investigation of antibiotic resistance.

    Science.gov (United States)

    Mullany, Peter

    2014-04-01

    Antibiotic resistance is a major threat to human health and well-being. To effectively combat this problem we need to understand the range of different resistance genes that allow bacteria to resist antibiotics. To do this the whole microbiota needs to be investigated. As most bacteria cannot be cultivated in the laboratory, the reservoir of antibiotic resistance genes in the non-cultivatable majority remains relatively unexplored. Currently the only way to study antibiotic resistance in these organisms is to use metagenomic approaches. Furthermore, the only method that does not require any prior knowledge about the resistance genes is functional metagenomics, which involves expressing genes from metagenomic clones in surrogate hosts. In this review the methods and limitations of functional metagenomics to isolate new antibiotic resistance genes and the mobile genetic elements that mediate their spread are explored.

  7. Predation and selection for antibiotic resistance in natural environments

    DEFF Research Database (Denmark)

    Leisner, Jørgen; Jørgensen, Niels O. G.; Middelboe, Mathias

    2016-01-01

    Genes encoding resistance to antibiotics appear, like the antibiotics themselves, to be ancient, originating long before the rise of the era of anthropogenic antibiotics. However, detailed understanding of the specific biological advantages of antibiotic resistance in natural environments is still...... lacking, thus limiting our efforts to prevent environmental influx of resistance genes. Here, we propose that antibiotic-resistant cells not only evade predation from antibiotic producers but also take advantage of nutrients released from cells that are killed by the antibiotic-producing bacteria. Thus......, predation is potentially an important mechanism for driving antibiotic resistance during slow or stationary phase of growth when nutrients are deprived. This adds to explain the ancient nature and widespread occurrence of antibiotic resistance in natural environments unaffected by anthropogenic antibiotics...

  8. Pediatric fecal microbiota harbor diverse and novel antibiotic resistance genes.

    Directory of Open Access Journals (Sweden)

    Aimée M Moore

    antibiotic pressure in the human host, and that cryptic gut microbes are an important resistance reservoir. The observed transferability of gut-associated resistance genes to a gram-negative (E. coli host also suggests that the potential for gut-associated resistomes to threaten human health by mediating antibiotic resistance in pathogens warrants further investigation.

  9. A review of the influence of treatment strategies on antibiotic resistant bacteria and antibiotic resistance genes.

    Science.gov (United States)

    Sharma, Virender K; Johnson, Natalie; Cizmas, Leslie; McDonald, Thomas J; Kim, Hyunook

    2016-05-01

    Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) in the aquatic environment have become an emerging contaminant issue, which has implications for human and ecological health. This review begins with an introduction to the occurrence of ARB and ARG in different environmental systems such as natural environments and drinking water resources. For example, ARG or ARB with resistance to ciprofloxacin, sulfamethoxazole, trimethoprim, quinolone, vancomycin, or tetracycline (e.g., tet(A), tet(B), tet(C), tet(G), tet(O), tet(M), tet(W), sul I, and sul II) have been detected in the environment. The development of resistance may be intrinsic, may be acquired through spontaneous mutations (de novo), or may occur due to horizontal gene transfer from donor bacteria, phages, or free DNA to recipient bacteria. An overview is also provided of the current knowledge regarding inactivation of ARB and ARG, and the mechanism of the effects of different disinfection processes in water and wastewater (chlorination, UV irradiation, Fenton reaction, ozonation, and photocatalytic oxidation). The effects of constructed wetlands and nanotechnology on ARB and ARG are also summarized.

  10. Bacteriophage functional genomics and its role in bacterial pathogen detection.

    Science.gov (United States)

    Klumpp, Jochen; Fouts, Derrick E; Sozhamannan, Shanmuga

    2013-07-01

    Emerging and reemerging bacterial infectious diseases are a major public health concern worldwide. The role of bacteriophages in the emergence of novel bacterial pathogens by horizontal gene transfer was highlighted by the May 2011 Escherichia coli O104:H4 outbreaks that originated in Germany and spread to other European countries. This outbreak also highlighted the pivotal role played by recent advances in functional genomics in rapidly deciphering the virulence mechanism elicited by this novel pathogen and developing rapid diagnostics and therapeutics. However, despite a steady increase in the number of phage sequences in the public databases, boosted by the next-generation sequencing technologies, few functional genomics studies of bacteriophages have been conducted. Our definition of 'functional genomics' encompasses a range of aspects: phage genome sequencing, annotation and ascribing functions to phage genes, prophage identification in bacterial sequences, elucidating the events in various stages of phage life cycle using genomic, transcriptomic and proteomic approaches, defining the mechanisms of host takeover including specific bacterial-phage protein interactions and identifying virulence and other adaptive features encoded by phages and finally, using prophage genomic information for bacterial detection/diagnostics. Given the breadth and depth of this definition and the fact that some of these aspects (especially phage-encoded virulence/adaptive features) have been treated extensively in other reviews, we restrict our focus only on certain aspects. These include phage genome sequencing and annotation, identification of prophages in bacterial sequences and genetic characterization of phages, functional genomics of the infection process and finally, bacterial identification using genomic information.

  11. 新生儿败血症病原菌分布及耐药性10年回顾分析%Retrospective analysis of distribution and antibiotic resistance of pathogenic bacteria in neonatal sepsis over 10 years

    Institute of Scientific and Technical Information of China (English)

    黄梦; 李克诚; 徐旭

    2014-01-01

    目的:分析新生儿败血症病原菌及细菌耐药情况。方法回顾性分析2004年1月至2013年12月收治的新生儿败血症的血培养病原菌分布及药敏结果,比较前后5年的变化。结果前后5年间,无乳链球菌检出构成比由1.0%上升至4.2%,真菌由1.9%上升到7.9%,但新生儿血培养各细菌检出分布的差异无统计学意义(P=0.282);大肠埃希菌的超广谱β-内酰胺酶(ESBLs)发生概率由28.6%升至36.0%,但差异无统计学意义(P>0.05),未发现对亚胺培南、美罗培南耐药大肠埃希菌;葡萄球菌对苯唑西林和氨苄西林舒巴坦的耐药性升高,差异有统计学意义(P均0.05). The Escherichia coli resistant to imipenem and meropenem had not been found. The Staphylococcus resistance to oxacallin and ampicillin/sulbactam was increased. The Staphylococcus resistant to vancomycin had not been found. Conclusions The main pathogens of neonatal sepsis are coagulase-negative staphylococci and E. coli. The fungi and Streptococcus agalactiae infections are signiifcantly increased.

  12. Bacterial pathogen phytosensing in transgenic tobacco and Arabidopsis plants.

    Science.gov (United States)

    Liu, Wusheng; Mazarei, Mitra; Rudis, Mary R; Fethe, Michael H; Peng, Yanhui; Millwood, Reginald J; Schoene, Gisele; Burris, Jason N; Stewart, C Neal

    2013-01-01

    Plants are subject to attack by a wide range of phytopathogens. Current pathogen detection methods and technologies are largely constrained to those occurring post-symptomatically. Recent efforts were made to generate plant sentinels (phytosensors) that can be used for sensing and reporting pathogen contamination in crops. Engineered phytosensors indicating the presence of plant pathogens as early-warning sentinels potentially have tremendous utility as wide-area detectors. We previously showed that synthetic promoters containing pathogen and/or defence signalling inducible cis-acting regulatory elements (RE) fused to a fluorescent protein (FP) reporter could detect phytopathogenic bacteria in a transient phytosensing system. Here, we further advanced this phytosensing system by developing stable transgenic tobacco and Arabidopsis plants containing candidate constructs. The inducibility of each synthetic promoter was examined in response to biotic (bacterial pathogens) or chemical (plant signal molecules salicylic acid, ethylene and methyl jasmonate) treatments using stably transgenic plants. The treated plants were visualized using epifluorescence microscopy and quantified using spectrofluorometry for FP synthesis upon induction. Time-course analyses of FP synthesis showed that both transgenic tobacco and Arabidopsis plants were capable to respond in predictable ways to pathogen and chemical treatments. These results provide insights into the potential applications of transgenic plants as phytosensors and the implementation of emerging technologies for monitoring plant disease outbreaks in agricultural fields.

  13. Temperature dependent bacteriophages of a tropical bacterial pathogen

    Directory of Open Access Journals (Sweden)

    Martha Rebecca Jane Clokie

    2014-11-01

    Full Text Available There is an increasing awareness of the multiple ways that bacteriophages (phages influence bacterial evolution, population dynamics, physiology and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model Burkholderia thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C, the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C, the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial life, and on our ability to culture and correctly enumerate viable bacteria.

  14. Investigation of magnetic microdiscs for bacterial pathogen detection

    Science.gov (United States)

    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.

  15. Temperature dependent bacteriophages of a tropical bacterial pathogen

    Science.gov (United States)

    Shan, Jinyu; Korbsrisate, Sunee; Withatanung, Patoo; Adler, Natalie Lazar; Clokie, Martha R. J.; Galyov, Edouard E.

    2014-01-01

    There is an increasing awareness of the multiple ways that bacteriophages (phages) influence bacterial evolution, population dynamics, physiology, and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model B. thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C), the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C), the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial biology, and on our ability to culture and correctly enumerate viable bacteria. PMID:25452746

  16. Protease-dependent mechanisms of complement evasion by bacterial pathogens.

    Science.gov (United States)

    Potempa, Michal; Potempa, Jan

    2012-09-01

    The human immune system has evolved a variety of mechanisms for the primary task of neutralizing and eliminating microbial intruders. As the first line of defense, the complement system is responsible for rapid recognition and opsonization of bacteria, presentation to phagocytes and bacterial cell killing by direct lysis. All successful human pathogens have mechanisms of circumventing the antibacterial activity of the complement system and escaping this stage of the immune response. One of the ways in which pathogens achieve this is the deployment of proteases. Based on the increasing number of recent publications in this area, it appears that proteolytic inactivation of the antibacterial activities of the complement system is a common strategy of avoiding targeting by this arm of host innate immune defense. In this review, we focus on those bacteria that deploy proteases capable of degrading complement system components into non-functional fragments, thus impairing complement-dependent antibacterial activity and facilitating pathogen survival inside the host.

  17. The role of surveillance systems in confronting the global crisis of antibiotic-resistant bacteria

    Science.gov (United States)

    Perez, Federico; Villegas, Maria Virginia

    2015-01-01

    Purpose of Review It is widely accepted that infection control, advanced diagnostics, and novel therapeutics are crucial to mitigate the impact of antibiotic-resistant bacteria. The role of global, national and regional surveillance systems as part of the response to the challenge posed by antibiotic resistance is not sufficiently highlighted. We provide an overview of contemporary surveillance programs, with emphasis on Gram-negative bacteria. Recent Findings The World Health Organization and public health agencies in Europe and the United States recently published comprehensive surveillance reports. These highlight the emergence and dissemination of carbapenem-resistant Enterobacteriaceae (CRE) and other multidrug resistant Gram-negative bacteria. In Israel, public health action to control CRE, especially Klebsiella pneumoniae carbapenemase (KPC) producing-Klebsiella pneumoniae, has advanced together with a better understanding of its epidemiology. Surveillance models adapted to the requirements and capacities of each country are in development. Summary Robust surveillance systems are essential to combat antibiotic resistance, and need to emphasize a “One Health” approach. Refinements in surveillance will come from advances in bioinformatics and genomics that permit the integration of global and local information about antibiotic consumption in humans and animals, molecular mechanisms of resistance, and bacterial genotyping. PMID:26098505

  18. Exposure to mutagenic disinfection byproducts leads to increase of antibiotic resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Lv, Lu; Jiang, Tao; Zhang, Shenghua; Yu, Xin

    2014-07-15

    Bacterial antibiotic resistance (BAR) in drinking water has become a global issue because of its risks on the public health. Usually, the antibiotic concentrations in drinking water are too low to select antibiotic resistant strains effectively, suggesting that factors other than antibiotics would contribute to the emergence of BAR. In the current study, the impacts of mutagenic disinfection byproducts (DBPs) on BAR were explored, using four typical DBPs: dibromoacetic acid, dichloroacetonitrile, potassium bromate, and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX). After exposure to DBPs, resistances to 10 individual antibiotics and multiple antibiotics were both raised by various levels, norfloxacin and polymycin B resistances were enhanced even greater than 10-fold compared with control. MX increased the resistance most observably in the selected DBPs, which was consistent with its mutagenic activity. The resistant mutants showed hereditary stability during 5-day culturing. The increase of BAR was caused by the mutagenic activities of DBPs, since mutation frequency declined by adding ROS scavenger. Mutagenesis was further confirmed by sequencing of the related genes. Our study indicated that mutagenic activities of the selected DBPs could induce antibiotic resistance, even multidrug resistance, which may partially explain the lack of agreement between BAR and antibiotic levels in drinking water.

  19. Surveillance of antibiotics resistance of pathogenic bacteria isolated from hospitalized patients in 2011%2011年住院患者分离病原菌对抗菌药物耐药监测

    Institute of Scientific and Technical Information of China (English)

    穆惠荣; 王继美

    2012-01-01

    OBJECTIVE To investigate the species and the drug resistance to common antibacterials of the pathogenic bacteria isolated from inpatients of Dongying People's Hospital, so as to provide reference for the clinical selection of antibiotics. METHODS The species of the kinds of microorganisms isolated during year 2011 and their antibacterial-resistance were analyzed by software WHONET5. 4. RESULTS A total of 1272 clinical isolates of non-repeated bacteria were isolated, including 868(68. 23%) strains of gram-negative bacteria, 284 (22. 32%)strains of gram-positive bacteria, and 120(9. 43%)strains of fungi. The drug resistance rates of methi-cillin-resistant Staphylococcus aureus(MRSA)to all the antibiotics except vancomycin, teicoplanin,fusidic acid,and quinupristin/dalfopristin were higher than 60. 0%. The positive rates of ESBLs-producing Klebsiella and Esche-richia coli were 50. 8% and 59. 1% , Except carbopenems, the drug resistance rate of the ESBLs-producing strains to all the antibiotics except carbapenems was significantly higher than that of the non-ESBLs-producing strains,and no strains of carbopenems-resistant strains were found. The detection rate and drug resistance of Pseudomonas aeruginosa varied little, the drug susceptibility rates to piperacillin/tazobactam,amikacin and cefoxitin were higher than 70. 0%. The detection rate and drug resistance of Acinetobacter baumannii increased significantly, the drug susceptibility rate was less than 35. 0% to all the tested antibiotics except carbopenems, four strains of A. baumannii strains simultaneously resistant to carbapenems were first reported. CONCLUSION The drug resistance of clinical isolates of bacteria to common antibacterials shows an upward tendency during the year 2011, the multidrug- resistant A. baumannii isolates are first detected, thus it is necessary to strengthen the clinical application management of antibiotics so as to control the nosocomial infections .%目的 了解东营市人民医院

  20. Characterization and comparative analysis of antibiotic resistance plasmids isolated from a wastewater treatment plant.

    Directory of Open Access Journals (Sweden)

    Teddie O Rahube

    2014-10-01

    Full Text Available A wastewater treatment plant (WWTP is an environment high in nutrient concentration with diverse bacterial populations and can provide an ideal environment for the proliferation of mobile elements such as plasmids. WWTPs have also been identified as reservoirs for antibiotic resistance genes that are associated with human pathogens. The objectives of this study were to isolate and characterize self-transmissible or mobilizable resistance plasmids associated with effluent from wastewater treatment plant. An enrichment culture approach designed to capture plasmids conferring resistance to high concentrations of erythromycin was used to capture plasmids from an urban wastewater treatment plant servicing a population of ca. 210,000. DNA sequencing of the plasmids revealed diversity of plasmids represented by incompatibility groups IncU, col-E, IncFII and IncP-1β. Genes coding resistance to clinically relevant antibiotics (macrolide, tetracycline, beta-lactam, trimethoprim, chloramphenicol, sulphonamide, quaternary ammonium compounds and heavy metals were co-located on these plasmids, often within transposable and integrative mobile elements. Several of the plasmids were self-transmissible or mobilizable and could be maintained in the absence of antibiotic selection. The IncFII plasmid pEFC36a showed the highest degree of sequence identity to plasmid R1 which has been isolated in England more than fifty years ago from a patient suffering from a Salmonella infection. Functional conservation of key regulatory features of this F-like conjugation module were demonstrated by the finding that the conjugation frequency of pEFC36a could be stimulated by the positive regulator of plasmid R1 DNA transfer genes, TraJ.

  1. Characterization and comparative analysis of antibiotic resistance plasmids isolated from a wastewater treatment plant.

    Science.gov (United States)

    Rahube, Teddie O; Viana, Laia S; Koraimann, Günther; Yost, Christopher K

    2014-01-01

    A wastewater treatment plant (WWTP) is an environment high in nutrient concentration with diverse bacterial populations and can provide an ideal environment for the proliferation of mobile elements such as plasmids. WWTPs have also been identified as reservoirs for antibiotic resistance genes that are associated with human pathogens. The objectives of this study were to isolate and characterize self-transmissible or mobilizable resistance plasmids associated with effluent from WWTP. An enrichment culture approach designed to capture plasmids conferring resistance to high concentrations of erythromycin was used to capture plasmids from an urban WWTP servicing a population of ca. 210,000. DNA sequencing of the plasmids revealed diversity of plasmids represented by incompatibility groups IncU, col-E, IncFII and IncP-1β. Genes coding resistance to clinically relevant antibiotics (macrolide, tetracycline, beta-lactam, trimethoprim, chloramphenicol, sulphonamide), quaternary ammonium compounds and heavy metals were co-located on these plasmids, often within transposable and integrative mobile elements. Several of the plasmids were self-transmissible or mobilizable and could be maintained in the absence of antibiotic selection. The IncFII plasmid pEFC36a showed the highest degree of sequence identity to plasmid R1 which has been isolated in England more than 50 years ago from a patient suffering from a Salmonella infection. Functional conservation of key regulatory features of this F-like conjugation module were demonstrated by the finding that the conjugation frequency of pEFC36a could be stimulated by the positive regulator of plasmid R1 DNA transfer genes, TraJ.

  2. Network-assisted investigation of virulence and antibiotic-resistance systems in Pseudomonas aeruginosa

    Science.gov (United States)

    Hwang, Sohyun; Kim, Chan Yeong; Ji, Sun-Gou; Go, Junhyeok; Kim, Hanhae; Yang, Sunmo; Kim, Hye Jin; Cho, Ara; Yoon, Sang Sun; Lee, Insuk

    2016-05-01

    Pseudomonas aeruginosa is a Gram-negative bacterium of clinical significance. Although the genome of PAO1, a prototype strain of P. aeruginosa, has been extensively studied, approximately one-third of the functional genome remains unknown. With the emergence of antibiotic-resistant strains of P. aeruginosa, there is an urgent need to develop novel antibiotic and anti-virulence strategies, which may be facilitated by an approach that explores P. aeruginosa gene function in systems-level models. Here, we present a genome-wide functional network of P. aeruginosa genes, PseudomonasNet, which covers 98% of the coding genome, and a companion web server to generate functional hypotheses using various network-search algorithms. We demonstrate that PseudomonasNet-assisted predictions can effectively identify novel genes involved in virulence and antibiotic resistance. Moreover, an antibiotic-resistance network based on PseudomonasNet reveals that P. aeruginosa has common modular genetic organisations that confer increased or decreased resistance to diverse antibiotics, which accounts for the pervasiveness of cross-resistance across multiple drugs. The same network also suggests that P. aeruginosa has developed mechanism of trade-off in resistance across drugs by altering genetic interactions. Taken together, these results clearly demonstrate the usefulness of a genome-scale functional network to investigate pathogenic systems in P. aeruginosa.

  3. Short communication: prevalence and antibiotic resistance of Staphylococcus aureus isolated from bovine clinical mastitis.

    Science.gov (United States)

    Jamali, Hossein; Radmehr, Behrad; Ismail, Salmah

    2014-01-01

    The aims of this study were to determine the prevalence and antibiotic resistance of Staphylococcus aureus isolated from bovine clinical mastitis in Varamin, Tehran Province, Iran. All of the isolated Staph. aureus were identified by morphology and culture and confirmed using the API Staph identification system (bioMérieux, Marcy-l'Étoile, France). Antibiotic resistance genes were detected by PCR with oligonucleotide primers specific for each gene. Staphylococcus aureus was recovered from 43 of 207 (20.1%) bovine clinical milk samples. Using disk diffusion, methicillin-resistant Staph. aureus was detected in 5 of 43 (11.6%) samples. The pathogen showed high resistance against penicillin G (86%) and tetracycline (76.7%). The blaZ (penicillin) (86%), tetM (tetracycline), and ermC (erythromycin) genes (39.5% each) were the most prevalent antibiotic resistance genes. The findings of this study are useful for designing specific control programs for bovine clinical mastitis caused by Staph. aureus in this region of Iran.

  4. Production of transgenic medaka with increased resistance to bacterial pathogens.

    Science.gov (United States)

    Sarmasik, Aliye; Warr, Gregory; Chen, Thomas T

    2002-06-01

    Cecropins, first identified in silk moth (Hyalophora cecropia), are a group of antimicrobial peptides with bactericidal activity against a broad spectrum of bacteria. In this study we investigated whether (1) this group of antimicrobial peptides could exhibit bactericidal activity toward known fish bacterial pathogens and (2) expression of cecropin transgenes in transgenic medaka (Oryzias latipas) could result in increasing resistance of the transgenic fish to infection by fish bacterial pathogens. Cecropin gene construct containing silk moth preprocecropin B, procecropin B and cecropin B, and porcine cecropin P1 driven by a cytomegalovirus (CMV) promoter were transfected into chinook salmon embryonic cells (CHSE-214) by lipofection, and the resulting permanent transformants were collected. In an "inhibition zone" assay medium isolated from each transformant exhibited strong bactericidal activity toward known fish bacterial pathogens such as Pseudomonas fluorescens, Aeromonas hydrophila, and Vibrio anguillarum. The same cecropin transgene constructs were introduced into newly fertilized medaka eggs by electroporation to produce transgenic fish. About 40% to 60% of the embryos survived from electroporation, and about 5% to 11% of the surviving fish were shown to contain cecropin transgenes by polymerase chain reaction analysis of genomic DNA samples isolated from presumptive transgenic fish. These P1 transgenic fish were used as founder stocks, and following generations of successive breeding, a total of 20 F2 families of transgenic fish were established. Expression of cecropin transgenes was detected in the F2 transgenics by reverse transcriptase polymerase chain reaction analysis. Southern blot analysis of genomic DNA isolated from different F2 fish showed that cecropin transgenes were integrated into the genomes of F2 transgenic fish. To determine whether transgenic fish carrying cecropin transgenes could exhibit resistance to infection by known fish bacterial

  5. Occurrence and persistence of antibiotic resistance genes in river biofilms after wastewater inputs in small rivers.

    Science.gov (United States)

    Proia, Lorenzo; von Schiller, Daniel; Sànchez-Melsió, Alexandre; Sabater, Sergi; Borrego, Carles M; Rodríguez-Mozaz, Sara; Balcázar, José Luis

    2016-03-01

    The extensive use of antibiotics in human and veterinary medicine and their subsequent release into the environment may have direct consequences for autochthonous bacterial communities, especially in freshwater ecosystems. In small streams and rivers, local inputs of wastewater treatment plants (WWTPs) may become important sources of organic matter, nutrients and emerging pollutants, such as antibiotic resistance genes (ARGs). In this study, we evaluated the effect of WWTP effluents as a source of ARGs in river biofilms. The prevalence of genes conferring resistance to main antibiotic families, such as beta-lactams (blaCTX-M), fluoroquinolones (qnrS), sulfonamides (sul I), and macrolides (ermB), was determined using quantitative PCR (qPCR) in biofilm samples collected upstream and downstream WWTPs discharge points in four low-order streams. Our results showed that the WWTP effluents strongly modified the hydrology, physico-chemistry and biological characteristics of the receiving streams and favoured the persistence and spread of antibiotic resistance in microbial benthic communities. It was also shown that the magnitude of effects depended on the relative contribution of each WWTP to the receiving system. Specifically, low concentrations of ARGs were detected at sites located upstream of the WWTPs, while a significant increase of their concentrations was observed in biofilms collected downstream of the WWTP discharge points (particularly ermB and sul I genes). These findings suggest that WWTP discharges may favour the increase and spread of antibiotic resistance among streambed biofilms. The present study also showed that the presence of ARGs in biofilms was noticeable far downstream of the WWTP discharge (up to 1 km). It is therefore reasonable to assume that biofilms may represent an ideal setting for the acquisition and spread of antibiotic resistance determinants and thus be considered suitable biological indicators of anthropogenic pollution by active

  6. Persistence of Antibiotic Resistance Plasmids in Biofilms

    Science.gov (United States)

    2014-10-01

    wounds, facilitates the persistence of MDR plasmids in Acinetobacter baumannii , a problematic wound pathogen. Moreover, we have shown that plasmids...which plasmid persistence can improve in Acinetobacter baumannii and other wound pathogens when grown in biofilm environments. This project has the... Acinetobacter * baumannii ,!Klebsiella*pneumoniae,!Enterobacter*sp.,! and! Escherichia* coli! (Eardley! et! al.,! 2011;! Gaynes! &! Edwards,! 2005;! Murray

  7. Antibiotic resistance patterns of Pseudomonas spp. isolated from the River Danube

    Directory of Open Access Journals (Sweden)

    Clemens eKittinger

    2016-05-01

    Full Text Available Spread and persistence of antibiotic resistance pose a severe threat to human health, yet there is still lack of knowledge about reservoirs of antibiotic resistant bacteria in the environment. We took the opportunity of the Joint Danube Survey 3 (JDS3, the world's biggest river research expedition of its kind in 2013, to analyse samples originating from different sampling points along the whole length of the river. Due to its high clinical relevance, we concentrated on the characterization of Pseudomonas spp. and evaluated the resistance profiles of Pseudomonas spp. which were isolated from eight sampling points. In total, 520 Pseudomonas isolates were found, 344 (66.0% isolates were identified as Pseudomonas putida, and 141 (27.1% as Pseudomonas fluorescens, all other Pseudomonas species were represented by less than five isolates, among those two P. aeruginosa isolates. Thirty seven percent (37% of all isolated Pseudomonas species showed resistance to at least one out of eleven tested antibiotics. The most common resistance was against meropenem (30.4% / 158 isolates piperacillin/tazobactam (10.6% / 55 isolates and ceftazidime (4.2% / 22 isolates. 16 isolates (3.1% / 16 isolates were multi-resistant. For each tested antibiotic at least one resistant isolate could be detected. Sampling points from the upper stretch of the River Danube showed more resistant isolates than downriver. Our results suggest that antibiotic resistance can be acquired by and persists even in Pseudomonas species that are normally not in direct contact with humans. A possible scenario is that these bacteria provide a reservoir of antibiotic resistance genes that can spread to related human pathogens by horizontal gene transfer.

  8. Detection of antibiotic resistance and tetracycline resistance genes in Enterobacteriaceae isolated from the Pearl rivers in South China

    Energy Technology Data Exchange (ETDEWEB)

    Tao Ran [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Ying Guangguo, E-mail: guangguo.ying@gmail.co [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Su Haochang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Zhou Hongwei [Department of Environmental Health, School of Public Health and Tropical Medicine, Southern Medical University, 1838 North Guangzhou Street, Baiyun District, Guangzhou 510515 (China); Sidhu, Jatinder P.S. [CSIRO Land and Water, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia QLD 4067 (Australia)

    2010-06-15

    This study investigated antibiotic resistance profiles and tetracycline resistance genes in Enterobacteriaceae family isolates from the Pearl rivers. The Enterobacteriaceae isolates were tested for susceptibility to seven antibiotics ampicillin, chloramphenicol, ciprofloxacin, levofloxacin, sulphamethoxazole/trimethoprim, tetracycline and trimethoprim. In Liuxi reservoir, with an exception to ampicillin resistant strains (11%) no other antibiotic resistance bacterial strains were detected. However, multiple drug resistance in bacte