Urban dust fecal pollution in Mexico City: antibiotic resistance and virulence factors of Escherichia coli. - Related Documents




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278201.0000Urban dust fecal pollution in Mexico City: antibiotic resistance and virulence factors of Escherichia coli. Fecal pollution of settled dust samples from indoor and outdoor urban environments, was measured and characterized by the presence of fecal coliforms (FC), and by the characterization of Escherichia coli virulence genes, adherence and antibiotic resistance traits as markers. There were more FC indoors than outdoors (mean values 1089 and 435MPN/g). Among indoor samples, there were more FC in houses with carpets and/or pets. Using a PCR-based assay for six enteropathogenicity genes (belonging to the EAEC, EHEC and EPEC pathotypes) on randomly selected E. coli isolates, there was no significant difference between isolates from indoors and outdoors (60% and 72% positive to at least one gene). The serotypes commonly associated with pathogenic strains, such as O86 and O28, were found in the indoor isolates; whereas O4, O66 and O9 were found amongst outdoor isolates. However, there were significantly more outdoor isolates resistant to at least one antibiotic (73% vs. 45% from indoors) among the strains positive for virulence factors, and outdoor isolates were more commonly multiresistant. There was no relationship between the presence of virulence genes and resistance traits. These results indicate that outdoor fecal bacteria were more likely from human sources, and those found indoors were related to pets and maintained in carpets. This study illustrates the risk posed by fecal bacteria from human sources, usually bearing virulence and resistance traits. Furthermore, the high prevalence of strains carrying genes associated to EAEC or EHEC pathotypes, in both indoor and outdoor environments, adds to the health risk.200616762593
284710.9995Phenotypic and genotypic antimicrobial resistance patterns of Escherichia coli and Klebsiella isolated from dairy farm milk, farm slurry and water in Punjab, India. Antibiotic resistance is a mushrooming pandemic at national and international levels which if not controlled at this very moment, can lead to global problems. Main reason for emerging bacterial resistance is repeated exposure of bacteria to antimicrobial agents and access of bacteria to increasingly large pools of antimicrobial resistance genes in mixed bacterial populations. A total of 51 villages were sampled in the current study contributing to a total of 153 farms. A total of 612 samples comprising 153 each of raw pooled milk samples, slurry, animal drinking water and human drinking water were gathered from small, medium and large farms located in all seven tehsils of Ludhiana district of Punjab. In addition to that, 37 samples of village pond water were also collected from the targeted villages. Out of total 153 slurry, raw pooled milk samples, animal drinking water and human drinking water samples (each), the prevalence of 24.8%, 60%, 26.7% and 16.3% was found for E. coli respectively. On the other hand, for Klebsiella, the overall prevalence of 19.6%, 51%, 20.2% and 5.8% was found from slurry, raw pooled milk samples, animal drinking water and human drinking water respectively. In all matrices, the comparative frequency of resistance genes in positive isolates of E. coli and K. pneumoniae was: tetA > tetB > tetC, qnrS > qnrB > qnrA, sulII > sulI > sulIII. The highest proportion of resistance genes was found in slurry (193 genes) followed by milk (71 genes). The overall pattern of resistant genes was tetA > sulII > qnrS. In conclusion, data from the present study suggested that commensal E. coli and Klebsiella may act as reservoirs of antimicrobial drug resistance genes which may be mobilised into human populations and untreated animal waste may be considered an important source of resistant bacteria leading to environmental pollution.202133544346
294520.9995Isolation and characterization of antimicrobial-resistant Escherichia coli from national horse racetracks and private horse-riding courses in Korea. Limited information is available regarding horse-associated antimicrobial resistant (AR) Escherichia (E.) coli. This study was designed to evaluate the frequency and characterize the pattern of AR E. coli from healthy horse-associated samples. A total of 143 E. coli (4.6%) were isolated from 3,078 samples collected from three national racetracks and 14 private horse-riding courses in Korea. Thirty of the E. coli isolates (21%) showed antimicrobial resistance to at least one antimicrobial agent, and four of the AR E. coli (13.3%) were defined as multi-drug resistance. Most of the AR E. coli harbored AR genes corresponding to their antimicrobial resistance phenotypes. Four of the AR E. coli carried class 1 integrase gene (intI1), a gene associated with multi-drug resistance. Pulsed-field gel electrophoretic analysis showed no genetic relatedness among AR E. coli isolated from different facilities; however, cross-transmissions between horses or horses and environments were detected in two facilities. Although cross-transmission of AR E. coli in horses and their environments was generally low, our study suggests a risk of transmission of AR bacteria between horses and humans. Further studies are needed to evaluate the risk of possible transmission of horse-associated AR bacteria to human communities through horse riders and horse-care workers.201626645344
294230.9995Longitudinal Shedding Patterns and Characterization of Antibiotic Resistant E. coli in Pastured Goats using a Cohort Study. There is a scarcity of information on antibiotic resistance in goats. To understand shedding of resistant Escherichia coli in pastured goats, we collected fecal samples from a mixed age cohort over a one-year period. No antibiotic had been used on the study animals one year prior to and during the study period. Resistant isolates were detected in all age groups and prevalence in goat kids was significantly higher than adults; 43-48% vs 8-25% respectively. The proportion of resistant isolates was higher when animals were congregated near handling facility than on pasture. Most isolates were resistant to tetracycline (51%) and streptomycin (30%), but also to antibiotics that had never been used on the farm; ampicillin (19%). TetB, bla(-TEM), (aadA and strpA/strpB) genes were detected in 70%, 43%, (44% and 24%) of tetracycline, ampicillin, and streptomycin resistant isolates respectively. Resistant isolates also harbored virulent genes and some belonged to D and B2 phylogenetic groups. Thus, pastured goats, despite minimal exposure to antibiotics, are reservoirs of resistant E. coli that may contaminate the environment and food chain and spread resistant genes to pathogenic bacteria and some that are potential animal and human pathogens. Environmental sources may play a role in acquisition of resistant bacteria in pastured goats.201931480769
287140.9995Antimicrobial resistance in generic Escherichia coli isolates from wild small mammals living in swine farm, residential, landfill, and natural environments in southern Ontario, Canada. To assess the impacts of different types of human activity on the development of resistant bacteria in the feces of wild small mammals, we compared the prevalences and patterns of antimicrobial resistance and resistance genes in generic Escherichia coli and Salmonella enterica isolates from fecal samples collected from wild small mammals living in four environments: swine farms, residential areas, landfills, and natural habitats. Resistance to antimicrobials was observed in E. coli isolates from animals in all environments: 25/52 (48%) animals trapped at swine farms, 6/69 (9%) animals trapped in residential areas, 3/20 (15%) animals trapped at landfills, and 1/22 (5%) animals trapped in natural habitats. Animals trapped on farms were significantly more likely to carry E. coli isolates with resistance to tetracycline, ampicillin, sulfisoxazole, and streptomycin than animals trapped in residential areas. The resistance genes sul2, aadA, and tet(A) were significantly more likely to be detected in E. coli isolates from animals trapped on farms than from those trapped in residential areas. Three S. enterica serotypes (Give, Typhimurium, and Newport) were recovered from the feces of 4/302 (1%) wild small mammals. All Salmonella isolates were pansusceptible. Our results show that swine farm origin is significantly associated with the presence of resistant bacteria and resistance genes in wild small mammals in southern Ontario, Canada. However, resistant fecal bacteria were found in small mammals living in all environments studied, indicating that environmental exposure to antimicrobials, antimicrobial residues, resistant bacteria, or resistance genes is widespread.201121131524
287550.9995Occurrence of virulence and antimicrobial resistance genes in Escherichia coli isolates from different aquatic ecosystems within the St. Clair River and Detroit River areas. Although the number of Escherichia coli bacteria in surface waters can differ greatly between locations, relatively little is known about the distribution of E. coli pathotypes in surface waters used as sources for drinking or recreation. DNA microarray technology is a suitable tool for this type of study due to its ability to detect high numbers of virulence and antimicrobial resistance genes simultaneously. Pathotype, phylogenetic group, and antimicrobial resistance gene profiles were determined for 308 E. coli isolates from surface water samples collected from diverse aquatic ecosystems at six different sites in the St. Clair River and Detroit River areas. A higher frequency (48%) of E. coli isolates possessing virulence and antimicrobial resistance genes was observed in an urban site located downstream of wastewater effluent outfalls than in the other examined sites (average of 24%). Most E. coli pathotypes were extraintestinal pathogenic E. coli (ExPEC) pathotypes and belonged to phylogenetic groups B2 and D. The ExPEC pathotypes were found to occur across all aquatic ecosystems investigated, including riverine, estuarine, and offshore lake locations. The results of this environmental study using DNA microarrays highlight the widespread distribution of E. coli pathotypes in aquatic ecosystems and the potential public health threat of E. coli pathotypes originating from municipal wastewater sources.200717085696
287760.9995Metagenomic insights into isolable bacterial communities and antimicrobial resistance in airborne dust from pig farms. This study aims to investigate bacterial communities and antimicrobial resistance (AMR) in airborne dust from pig farms. Airborne dust, pig feces and feed were collected from nine pig farms in Thailand. Airborne dust samples were collected from upwind and downwind (25 meters from pig house), and inside (in the middle of the pig house) of the selected pig house. Pig feces and feed samples were individually collected from the pen floor and feed trough from the same pig house where airborne dust was collected. A direct total bacteria count on each sampling plate was conducted and averaged. The ESKAPE pathogens together with Escherichia coli, Salmonella, and Streptococcus were examined. A total of 163 bacterial isolates were collected and tested for MICs. Pooled bacteria from the inside airborne dust samples were analyzed using Metagenomic Sequencing. The highest bacterial concentration (1.9-11.2 × 10(3) CFU/m(3)) was found inside pig houses. Staphylococcus (n = 37) and Enterococcus (n = 36) were most frequent bacterial species. Salmonella (n = 3) were exclusively isolated from feed and feces. Target bacteria showed a variety of resistance phenotypes, and the same bacterial species with the same resistance phenotype were found in airborne dust, feed and fecal from each farm. Metagenomic Sequencing analysis revealed 1,652 bacterial species across all pig farms, of which the predominant bacterial phylum was Bacillota. One hundred fifty-nine AMR genes of 12 different antibiotic classes were identified, with aminoglycoside resistance genes (24%) being the most prevalent. A total of 251 different plasmids were discovered, and the same plasmid was detected in multiple farms. In conclusion, the phenotypic and metagenomic results demonstrated that airborne dust from pig farms contained a diverse array of bacterial species and genes encoding resistance to a range of clinically important antimicrobial agents, indicating the significant role in the spread of AMR bacterial pathogens with potential hazards to human health. Policy measurements to address AMR in airborne dust from livestock farms are mandatory.202438872793
294370.9995Pilot study of antimicrobial-resistant Escherichia coli in herring gulls (Larus argentatus) and wastewater in the northeastern United States. Wildlife may be an important reservoir of antibiotic-resistant bacteria and resistance genes. In this pilot study, the prevalence and patterns of antimicrobial resistance in Escherichia coli cultured from wild herring gull (Larus argentatus) feces and human wastewater at Cape Cod, Massachusetts, USA, was compared. Antimicrobial susceptibility was tested using Kirby-Bauer disk diffusion with seven antimicrobial agents. A high proportion of antimicrobial agent-resistant E. coli isolates (59.2%) were detected in wastewater samples compared with a lower prevalence of 17.5% in gull feces. In addition, there was a large proportion of isolates with intermediate susceptibility (93.0%) in gull feces. Although similar resistance patterns and shared resistance genes suggest possible wastewater contamination of the local environment, the relatively low frequency of resistance and high prevalence of intermediate susceptibility detected in E. coli cultured from gull feces depict a complex model of antimicrobial resistance among E. coli strains of wildlife origin.201122946391
284980.9995Antibiotic-resistant bacteria and gut microbiome communities associated with wild-caught shrimp from the United States versus imported farm-raised retail shrimp. In the United States, farm-raised shrimp accounts for ~ 80% of the market share. Farmed shrimp are cultivated as monoculture and are susceptible to infections. The aquaculture industry is dependent on the application of antibiotics for disease prevention, resulting in the selection of antibiotic-resistant bacteria. We aimed to characterize the prevalence of antibiotic-resistant bacteria and gut microbiome communities in commercially available shrimp. Thirty-one raw and cooked shrimp samples were purchased from supermarkets in Florida and Georgia (U.S.) between March-September 2019. The samples were processed for the isolation of antibiotic-resistant bacteria, and isolates were characterized using an array of molecular and antibiotic susceptibility tests. Aerobic plate counts of the cooked samples (n = 13) varied from < 25 to 6.2 log CFU/g. Isolates obtained (n = 110) were spread across 18 genera, comprised of coliforms and opportunistic pathogens. Interestingly, isolates from cooked shrimp showed higher resistance towards chloramphenicol (18.6%) and tetracycline (20%), while those from raw shrimp exhibited low levels of resistance towards nalidixic acid (10%) and tetracycline (8.2%). Compared to wild-caught shrimp, the imported farm-raised shrimp harbored distinct gut microbiota communities and a higher prevalence of antibiotic-resistance genes in their gut. The presence of antibiotic-resistant strains in cooked shrimps calls for change in processing for their mitigation.202133558614
289590.9994Diversity of antimicrobial resistance genes and class-1-integrons in phylogenetically related porcine and human Escherichia coli. Antimicrobial resistant bacteria and resistance genes can be transferred between the microbial flora of humans and animals. To assess the dimension of this risk, we compared the phylogenetic ancestry of human and porcine tetracycline-insusceptible Escherichia coli. Further, we compared the resistance gene profiles (tetA/tetB/tetC/tetD/tetM/sulI/sulII/sulIII/strA-strB/addA) and the prevalence of class-1-integrons in isolates of identical and different phylogroups by endpoint-PCR. This is the first genotypic comparison of antimicrobial resistance in E. coli from humans and animals which allows for the phylogenetic ancestry of the isolates. E. coli isolates from diseased humans belonged regularly to phylogroup B2 (24.3%) or D (30.9%) and were rarely not typeable (7.2%); by contrast, isolates from pig manure were regularly not typeable (46.7%) and rarely grouped into phylogroup B2 (2.2%) or D (2.9%). Class-1-integrons were detected in 40.8% of clinical (n=152), in 9.5% of community-derived (n=21) and in 10.9% of porcine (n=137) E. coli. The prevalence of sulI (42.4%/16.0%) in phylogroup A and of tetA, tetB and sulII in phylogroup B1 differed significantly between human clinical and porcine strains. Human clinical isolates (except B2-isolates) carried significantly more different resistance genes per strain, compared to porcine or community-derived isolates. ERIC-PCR-analysis of B2- (and D-) isolates with identical genetic profiles revealed that only a minor part was clonally related. The dominant resistance gene profiles differed depending on phylogroup and source. Human and porcine isolates do not exceedingly share their genes, and might rapidly adapt their resistance gene equipment to meet the requirements of a new environment. The study underlines that resistance gene transfer between human and porcine isolates is limited, even in phylogenetically related isolates.201222854332
5309100.9994Use of Aeromonas spp. as General Indicators of Antimicrobial Susceptibility among Bacteria in Aquatic Environments in Thailand. Antimicrobials are widely used, not only for treating human infections, but also for treatment of livestock and in fish farms. Human habitats in Southeastern Asian countries are located in close proximity to aquatic environments. As such, the human populations within these regions are at risk of exposure to antimicrobial resistant bacteria, and thereby disseminating antimicrobial resistance genes (ARGs). In this study, we collected water samples from 15 sites (5 sites in Chao Phraya River, 2 sites at the mouth of Chao Phraya River, 3 sites in Ta Chin River, and 5 sites at city canals) and 12 sites (6 sites at city canals; 2 sites at chicken farms; 2 sites at pig farms; and 2 samples from sites at pig farms, which were subsequently treated at a biogas plant) in Thailand in 2013 and 2014, respectively. In total, 117 Aeromonas spp. were isolated from the water samples, and these organisms exhibited various antimicrobial susceptibility profiles. Notably, there was a significant correlation between the environmental concentration of tetracyclines and the rates of tetracycline resistance in the isolated Aeromonas spp.; however, both the concentration and rates of tetracycline resistance in samples derived from pig farms were higher than those of samples harvested from other aquatic environments. These findings suggest that the high concentrations of antimicrobials observed in these aquatic environments likely select for ARGs. Furthermore, they indicate that Aeromonas spp. comprise an effective marker for monitoring antimicrobial resistance in aquatic environments.201627433156
2897110.9994The Role of Flies in Disseminating Plasmids with Antimicrobial-Resistance Genes Between Farms. Dissemination of antimicrobial resistance is a major global public health concern. To clarify the role of flies in disseminating antimicrobial resistance between farms, we isolated and characterized tetracycline-resistant Escherichia coli strains isolated from flies and feces of livestock from four locations housing swine (abattoir, three farms) and three cattle farms. The percentages of isolates from flies resistant to tetracycline, dihydrostreptomycin, ampicillin, and chloramphenicol (80.8%, 61.5%, 53.8%, and 50.0%, respectively) and those from animal feces (80.5%, 78.0%, 41.5%, and 46.3%, respectively) in locations housing swine were significantly higher than those from cattle farms (p<0.05). The rates of resistance in E. coli derived from flies reflected those derived from livestock feces at the same locations, suggesting that antimicrobial resistance spreads between livestock and flies on the farms. The results of pulsed-field gel electrophoresis (PFGE) analysis showed that, with a few exceptions, all E. coli isolates differed. Two pairs of tetracycline-resistant strains harbored similar plasmids with the same tetracycline-resistance genes, although the origin (fly or feces), site of isolation, and PFGE patterns of these strains differed. Therefore, flies may disseminate the plasmids between farms. Our results suggest that flies may be involved not only in spreading clones of antimicrobial-resistant bacteria within a farm but also in the widespread dissemination of plasmids with antimicrobial resistance genes between farms.201526061440
2842120.9994Assessing antimicrobial and metal resistance genes in Escherichia coli from domestic groundwater supplies in rural Ireland. Natural ecosystems can become significant reservoirs and/or pathways for antimicrobial resistance (AMR) dissemination, with the potential to affect nearby microbiological, animal, and ultimately human communities. This is further accentuated in environments that provide direct human exposure, such as drinking water. To date, however, few studies have investigated AMR dissemination potential and the presence of co-selective stressors (e.g., metals/metalloids) in groundwater environments of human health significance. Accordingly, the present study analysed samples from rural (drinking) groundwater supplies (i.e., private wells) in the Republic of Ireland, where land use is dominated by livestock grazing activities. In total, 48 Escherichia coli isolates tested phenotypically for antimicrobial susceptibility in an earlier study were further subject to whole genome sequencing (WGS) and corresponding water samples were further analysed for trace metal/metalloid concentrations. Eight isolates (i.e., 16.7%) were genotypically resistant to antimicrobials, confirming prior phenotypic results through the identification of ten antimicrobial resistance genes (ARGs); namely: aph(3″)-lb (strA; n=7), aph(6)-Id (strA; n = 6), blaTEM (n = 6), sul2 (n = 6), tetA (n = 4), floR (n = 2), dfrA5 (n = 1), tetB (n = 1), and tetY (n = 1). Additional bioinformatic analysis revealed that all ARGs were plasmid-borne, except for two of the six sul2 genes, and that 31.2% of all tested isolates (n = 15) and 37.5% of resistant ones (n = 3) carried virulence genes. Study results also found no significant relationships between metal concentrations and ARG abundance. Additionally, just one genetic linkage was identified between ARGs and a metal resistance gene (MRG), namely merA, a mercury-resistant gene found on the same plasmid as blaTEM, dfrA5, strA, strB, and sul2 in the only isolate of inferred porcine (as opposed to bovine) origin. Overall, findings suggest that ARG (and MRG) acquisition may be occurring prior to groundwater ingress, and are likely a legacy issue arising from agricultural practices.202337343911
2873130.9994Microbiological Quality and Prevalence of β-Lactam Antibiotic Resistance Genes in Oysters ( Crassostrea rhizophorae ). The microbiological quality of oysters reflects the microbiological quality of their habitats because they are filter feeders. The objective of this study was to assess the bacterial composition of the edible oyster Crassostrea rhizophorae in urban and preserved estuaries. Particularly, we assessed the presence of pathogenic bacteria, investigated antibiotic susceptibility in bacterial isolates, and quantified β-lactam antibiotic resistance genes (bla(TEM), bla(SHV), and bla(KPC)) via quantitative PCR of oyster DNA. Our results detected total coliforms, Escherichia coli , and enterobacteria in the oysters from urban estuaries, which is indicative of poor water quality. In addition, our detection of the eaeA and stxA2 virulence genes in 16.7% of E. coli isolates from oysters from this region suggests the presence of multiantibiotic-resistant enteropathogenic and enterohemorrhagic E. coli strains. During periods of low precipitation, increased contamination by E. coli (in winter) and Vibrio parahaemolyticus (in autumn) was observed. In contrast, cultivated oysters inhabiting monitored farms in preserved areas had low levels of bacterial contamination, emphasizing that oyster culture monitoring enhances food quality and makes oysters fit for human consumption. Distinct antibiotic resistance profiles were observed in bacteria isolated from oysters collected from different areas, including resistance to β-lactam antibiotics. The presence of the bla(TEM) gene in 91.3% of oyster samples indicated that microorganisms in estuarine water conferred the capability to produce β-lactamase. To our knowledge, this is the first study to directly quantify and detect β-lactam antibiotic resistance genes in oysters. We believe our study provides baseline data for bacterial dynamics in estuarine oysters; such knowledge contributes to developing risk assessments to determine the associated hazards and consequences of consuming oysters from aquatic environments containing pathogenic bacteria that may possess antibiotic resistance genes.201728207310
2878140.9994Risk factors for antimicrobial resistance among fecal Escherichia coli from residents on forty-three swine farms. Fecal Escherichia coli (n = 555) were isolated from 115 residents on 43 farrow-to-finish swine farms to determine the prevalence of antimicrobial resistance and associated risk factors. Susceptibility to 21 antimicrobials was determined and the overall prevalence of antimicrobial resistance was 25.8%. Pair-wise difference in prevalences of resistance to individual antimicrobials was significant between isolates from residents on farms that fed medicated swine rations compared to those that did not (p = 0.013). Cross-resistance among antimicrobials of same class and multidrug-resistance were observed. Logistic regression models revealed the following risk factors positively associated with antimicrobial resistance: use of antimicrobials in pigs on farms; number of hours per week that farmers spent in their pig barns; handling of sick pigs; and intake of antimicrobials by farm residents. This study indicates that occupational exposure of farmers to resistant bacteria and use of antimicrobials in pig farming may constitute a source of resistance in humans, although the human health impacts of such resistance is unknown. The consumption of antimicrobials by farmers appeared to constitute a significant risk for resistance development. Fecal E. coli from farm residents may act as a reservoir of resistance genes for animal and/or human pathogens.200717536936
2892150.9994Characterization and transferability of class 1 integrons in commensal bacteria isolated from farm and nonfarm environments. This study assessed the distribution of class 1 integrons in commensal bacteria isolated from agricultural and nonfarm environments, and the transferability of class 1 integrons to pathogenic bacteria. A total of 26 class 1 integron-positive isolates were detected in fecal samples from cattle operations and a city park, water samples from a beef ranch and city lakes, and soil, feed (unused), manure, and compost samples from a dairy farm. Antimicrobial susceptibility testing of class 1 integron-positive Enterobacteriaceae isolates from city locations displayed multi-resistance to 12-13 out of the 22 antibiotics tested, whereas class 1 integron-positive Enterobacteriaceae isolates from cattle operations only displayed tetracycline resistance. Most class 1 integrons had one gene cassette belonging to the aadA family that confers resistance to streptomycin and spectinomycin. One isolate from a dog fecal sample collected from a city dog park transferred its class 1 integron to a strain of Escherichia coli O157:H7 at a frequency of 10(-7) transconjugants/donor by in vitro filter mating experiments under the stated laboratory conditions. Due to the numerous factors that may affect the transferability testing, further investigation using different methodologies may be helpful to reveal the transferability of the integrons from other isolates. The presence of class 1 integrons among diverse commensal bacteria from agricultural and nonfarm environments strengthens the possible role of environmental commensals in serving as reservoirs of antibiotic resistance genes.201020704511
2890160.9994Genetic diversity and antimicrobial resistance of Escherichia coli from Tagus estuary (Portugal). Fecal pollution of surface waters is a current world-wide public health concern and may contribute for the dissemination of antibiotic resistance. The Tagus estuary located in the south of Portugal is one of the largest wetlands in the west coast of Europe. In this study, water samples were collected from seven stations with different anthropic pressures along the estuary and evaluated for water quality indicator bacteria. Escherichia coli isolates (n=350) were typed by REP-PCR. Representatives of each REP profile (n=220) were evaluated phenotypically for resistance to 17 antibiotics and characterized in terms of phylogenetic group. Resistant isolates were screened for the presence of antibiotic resistance genes (tet(A), tet(B), sul1, sul2, qnrA, qnrB, qnrS, aacA4-cr, bla(TEM), bla(SHV), bla(CTX-M), bla(CMY-like), bla(IMP), bla(VIM)) and integrase genes (intI1 and intI2). The highest antibiotic resistance prevalence was observed for streptomycin and tetracycline followed by β-lactams and sulphonamides. Among E. coli isolates, 65.16% were resistant to at least one of the 17 antibiotics tested and approximately 19% were multiresistant. In our E. coli population phylo-groups A and D were predominant and characterized by higher prevalence of the antibiotic resistance. intI1 and intI2 genes were found in 12% of the isolates with prevalence of class 1 integrons. A strong correlation between the prevalence of integrons and multiresistance was observed. Differences in terms of antibiotic resistance between phylogenetic groups and between sampling sites were statistically significant. The results demonstrate a high prevalence of antibiotic resistance among E. coli circulating in the Tagus estuary with emphasis on the occurrence of resistance to last-resort antibiotics and on the high incidence of multiresistance.201323714246
2837170.9994Molecular evidence of the close relatedness of clinical, gull and wastewater isolates of quinolone-resistant Escherichia coli. Escherichia coli with reduced susceptibility to quinolones isolated from different environmental sources (urban wastewater treatment plants, n=61; hospital effluent, n=10; urban streams, n=9; gulls, n=18; birds of prey, n=17) and from hospitalised patients (n=28) were compared based on multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). The habitats with the most diversified genotypes of quinolone-resistant E. coli, corresponding to the highest genetic diversity (H'), were wastewater and gulls. In addition, genetically distinct populations were observed in clinical samples and birds of prey, suggesting the influence of the habitat or selective pressures on quinolone-resistant E. coli. The close genetic relatedness between isolates of clinical origin and from gulls and wastewater suggests the existence of potential routes of propagation between these sources. The most common sequence types were ST131 and ST10, with ST131 being highly specific to patients, although distributed in all of the other habitats except birds of prey. The prevalence of antimicrobial resistance was significantly higher in isolates from patients and gulls than from other sources (P<0.01), suggesting that the effect of selective pressures met by isolates subjected to strong human impacts. The evidence presented suggests the potential circulation of bacteria between the environmental and clinical compartments, with gulls being a relevant vector of bacteria and resistance genes.201527842875
5579180.9994Survey of Shiga toxigenic Escherichia coli O157 and drug-resistant coliform bacteria from in-line milk filters on dairy farms in the Czech Republic. AIMS: To determine the occurrence of Shiga toxin-producing Escherichia coli (STEC) O157 and coliform bacteria isolates resistant to antimicrobial agents in dairy herds by examining milk filters and to analyse the influence of management factors and antibiotic use on antimicrobial resistance. METHODS AND RESULTS: A total of 192 in-line milk filters were sampled on 192 dairy farms in the Czech Republic. Information on feeding, husbandry, production, and antibiotic therapy were obtained by questionnaire. The milk filters were cultured for STEC O157 and coliform bacteria. All recovered isolates were examined for antimicrobial susceptibility and presence of antimicrobial-resistance genes. STEC O157 was detected in four (2%) of the filters. Resistant nonpathogenic E. coli and coliform bacteria isolates with specific genes were detected in 44 (23%) of the filters. CONCLUSIONS: The study demonstrated a high prevalence of resistant coliform bacteria in milk filters obtained on Czech dairy farms. SIGNIFICANCE AND IMPACT OF THE STUDY: The occurrence of resistant coliform bacteria in milk filters was significantly higher among isolates from farms where antibiotic therapy against mastitis was employed during the dry period (P < 0.05).200817953684
2872190.9994Escherichia coli Antibiotic Resistance Patterns from Co-Grazing and Non-Co-Grazing Livestock and Wildlife Species from Two Farms in the Western Cape, South Africa. Although limited, studies have found conflicting results on whether co-grazing results in significant antibiotic resistance transfer between species. This type of farming system can act as a vector in the geographical spread of antibiotic-resistant bacteria in the environment. The aim of this study was to determine the antibiotic-resistant patterns between co-grazing and non-co-grazing livestock and wildlife species in South Africa. Escherichia coli was isolated from the faeces of various wildlife and livestock species from two farms in South Africa and was tested for antibiotic resistance using the Kirby-Bauer disk diffusion method against chloramphenicol, nalidixic acid, ampicillin, streptomycin, sulphafurazole, and tetracycline. A selection of some common antibiotic-resistant genes (blaCMY, aadA1, sul1, sul2, tetA, and tetB) were detected using PCR. The E. coli isolates from wildlife and livestock that co-grazed showed no significant differences in antibiotic resistance patterns. However, this was not the case for tetracycline resistance as the livestock isolates were significantly more resistant than the co-grazing wildlife isolates. The E. coli isolates from the non-co-grazing livestock and wildlife had significant differences in their antibiotic susceptibility patterns; the wildlife E. coli isolates were significantly more resistant to sulphafurazole and streptomycin than the livestock isolates, whilst those isolated from the cattle were significantly more resistant to ampicillin than the wildlife and sheep isolates. The results of this study suggest that there could be an exchange of antibiotic-resistant bacteria and genes between livestock and wildlife that co-graze.202134067232