Genetic but No Phenotypic Associations between Biocide Tolerance and Antibiotic Resistance in Escherichia coli from German Broiler Fattening Farms. - Related Documents




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572801.0000Genetic but No Phenotypic Associations between Biocide Tolerance and Antibiotic Resistance in Escherichia coli from German Broiler Fattening Farms. Biocides are frequently applied as disinfectants in animal husbandry to prevent the transmission of drug-resistant bacteria and to control zoonotic diseases. Concerns have been raised, that their use may contribute to the selection and persistence of antimicrobial-resistant bacteria. Especially, extended-spectrum β-lactamase- and AmpC β-lactamase-producing Escherichia coli have become a global health threat. In our study, 29 ESBL-/AmpC-producing and 64 NON-ESBL-/AmpC-producing E.coli isolates from three German broiler fattening farms collected in 2016 following regular cleaning and disinfection were phylogenetically characterized by whole genome sequencing, analyzed for phylogenetic distribution of virulence-associated genes, and screened for determinants of and associations between biocide tolerance and antibiotic resistance. Of the 30 known and two unknown sequence types detected, ST117 and ST297 were the most common genotypes. These STs are recognized worldwide as pandemic lineages causing disease in humans and poultry. Virulence determinants associated with extraintestinal pathogenic E.coli showed variable phylogenetic distribution patterns. Isolates with reduced biocide susceptibility were rarely found on the tested farms. Nine isolates displayed elevated MICs and/or MBCs of formaldehyde, chlorocresol, peroxyacetic acid, or benzalkonium chloride. Antibiotic resistance to ampicillin, trimethoprim, and sulfamethoxazole was most prevalent. The majority of ESBL-/AmpC-producing isolates carried bla(CTX-M) (55%) or bla(CMY-2) (24%) genes. Phenotypic biocide tolerance and antibiotic resistance were not interlinked. However, biocide and metal resistance determinants were found on mobile genetic elements together with antibiotic resistance genes raising concerns that biocides used in the food industry may lead to selection pressure for strains carrying acquired resistance determinants to different antimicrobials.202133801066
204310.9999Antimicrobial Resistance Genotypes and Mobile Genetic Elements of Poultry-Derived Escherichia coli: A Retrospective Genomic Study from the United States. The presence of antibiotic resistance in commensal bacteria may be an influential factor in the persistence of resistance in pathogens. This is especially critical for Escherichia coli that consumers may be exposed to through the consumption of uncooked meat. In this study, E. coli isolates previously recovered from poultry in the US between 2001 and 2012 were whole-genome sequenced to identify their antibiotic resistance genes and mobile genetic elements. The genomes of 98 E. coli isolates from poultry carcass rinsates and 2 isolates from poultry diagnostic samples with multidrug resistance or potential extended-spectrum β-lactam (ESBL)-producing phenotypes as well as the genetic variabilities among the E. coli were assessed. All E. coli isolates were positive for at least one antibiotic resistance gene and plasmid replicon, with 37 resistance genes and 27 plasmid replicons detected among the isolates. While no ESBL genes were detected, bla(CMY-2) was the most common β-lactamase gene, and bla(TEM) and bla(CARB-2) were also identified. Most isolates (95%) harbored at least one intact phage, and as many as seven intact phages were identified in one isolate. These results show the occurrence of antibiotic resistance genes and mobile genetic elements in these 100 poultry-associated E. coli isolates, which may be responsible for the resistance phenotypes exhibited by the isolates. This retrospective study also enables comparisons of resistance genes and mobile genetic elements from more recent E. coli isolates associated with poultry to aid in understanding the trends of both antibiotic resistance phenotypes and genotypes in the poultry setting over time.202540872236
159120.9999Influence of agricultural practice on mobile bla genes: IncI1-bearing CTX-M, SHV, CMY and TEM in Escherichia coli from intensive farming soils. Many calls have been made to address antibiotic resistance in an environmental perspective. With this study, we showed the widespread presence of high-level antibiotic resistant isolates on a collection of non-susceptible Gram-negative bacteria (n = 232) recovered from soils. Bacteria were selected using amoxicillin, cefotaxime and imipenem, from sites representing different agricultural practices (extensive, intensive and organic). Striking levels of non-susceptibility were noticed in intensive soils for norfloxacin (74%), streptomycin (50.7%) and tetracycline (46.6%); indeed, the exposure to intensive agricultural practices constituted a risk factor for non-susceptibility to many antibiotics, multidrug resistance and production of extended-spectrum β-lactamases (ESBL). Analyses of non-susceptibility highlighted that environmental and clinical bacteria from the same species might not share the same intrinsic resistance patterns, raising concerns for therapy choices in environment-borne infections. The multiple sequence-type IncI1-driven spread of penicillinases (blaTEM-1, blaTEM-135), ESBL (blaSHV-12 and blaCTX-M-1) and plasmid-mediated AmpC β-lactamases (blaCMY-2), produced by isolates that share their molecular features with isolates from humans and animals, suggests contamination of agricultural soils. This is also the first appearance of IncI1/ST28-harbouring blaCTX-M-1, which should be monitored to prevent their establishment as successfully dispersed plasmids. This research may help disclose paths of contamination by mobile antibiotic resistance determinants and the risks for their dissemination.201626279315
196430.9999Antimicrobial resistance of pet-derived bacteria in China, 2000-2020. With the rapid growth of the pet industry in China, bacterial infectious diseases in pets have increased, highlighting the need to monitor antimicrobial resistance (AMR) in pet-derived bacteria to improve the diagnosis and treatment. Before the establishment of the China Antimicrobial Resistance Surveillance Network for Pets (CARPet) in 2021, a comprehensive analysis of such data in China was lacking. Our review of 38 point-prevalence surveys conducted between 2000 and 2020 revealed increasing trends in AMR among pet-derived Escherichia coli, Klebsiella pneumoniae, Staphylococcus spp., Enterococcus spp., and other bacterial pathogens in China. Notable resistance to β-lactams and fluoroquinolones, which are largely used in both pets and livestock animals, was observed. For example, resistance rates for ampicillin and ciprofloxacin in E. coli frequently exceeded 50.0%, with up to 41.3% of the isolates producing extended-spectrum β-lactamases. The emergence of carbapenem-resistant K. pneumoniae and E. coli, carrying bla(NDM) and bla(OXA) genes, highlighted the need for vigilant monitoring. The detection rate of SCCmec (Staphylococcal Cassette Chromosome mec), a genetic element associated with methicillin resistance, in Staphylococcus pseudintermedius isolated from pets in China was found to be over 40.0%. The resistance rate of E. faecalis to vancomycin was 2.1% (5/223) in East China, which was higher than the detection rate of human-derived vancomycin-resistant Enterococcus (0.1%, 12/11,215). Establishing the national AMR surveillance network CARPet was crucial, focusing on representative cities, diverse clinical samples, and including both commonly used antimicrobial agents in veterinary practice and critically important antimicrobial agents for human medicine, such as carbapenems, tigecycline, and vancomycin.202540135877
557040.9999Monitoring the Spread of Multidrug-Resistant Escherichia coli Throughout the Broiler Production Cycle. The extensive use of antimicrobials in broiler production is changing the bird microbiota, fostering drug-resistant bacteria, and complicating therapeutic interventions, making the problem of multidrug resistance global. The monitoring of antimicrobial virulence and resistance genes are tools that have come to assist the breeding of these animals, directing possible treatments as already used in human medicine and collecting data to demonstrate possible dissemination of multidrug-resistant strains that may cause damage to industry and public health. This work aimed to monitor broiler farms in southern Brazil, isolating samples of E. coli and classifying them according to the profile of resistance to antimicrobials of interest to human and animal health. We also monitored the profile of virulence genes and conducted an epidemiological survey of possible risk factors that contribute to this selection of multidrug-resistant isolates. Monitoring was carried out on farms in the three southern states of the country, collecting samples of poultry litter, cloacal swabs, and beetles of the species Alphitobius diaperinus, isolating E. coli from each of these samples. These were evaluated by testing their susceptibility to antimicrobials of animal and human interest; detecting whether the samples were extended-spectrum β-lactamase enzyme (ESBL) producers; and when positive, selected for genotypic tests to identify resistant genes (CTX-M, TEM, and SHV) and virulence. Among the antimicrobials tested, enrofloxacin and ciprofloxacin demonstrated some of the highest frequencies of resistance in the isolated strains, with significant statistical results. The use of these antimicrobials increased the likelihood of resistance by over three times and was associated with a 1.5-fold higher probability of multidrug resistance. Of all isolates, 95% were multidrug-resistant, raising concerns for production and public health. Among 231 ESBL-positive samples, the CTX-M1 group predominated.202539858355
557150.9999ESβL E. coli isolated in pig's chain: Genetic analysis associated to the phenotype and biofilm synthesis evaluation. Resistance to new generation cephalosporins is an important public health problem globally, in terms of economic and social costs, morbidity and mortality. Βeta-lactamase enzymes are mainly responsible for the antibiotic resistance of Gram negative bacteria and extended-spectrum-β-lactamases (ESβLs) are one of the major determinants of resistance against oxymino-cephalosporins in Enterobacteriaceae. Food-producing animals represent one of the sources of antibiotic resistant bacteria, including pigs. Here we analysed the presence of E. coli resistant to III generation cephalosporins isolated from different matrices collected from intensively bred pigs. A total of 498 E. coli were isolated from faeces and carcasses of pigs at slaughterhouse as well as from pork meat and sausages. Among these, 73 were phenotypically confirmed to be ESβL producers. Genetic analysis revealed that all except two harboured at least one of the three selected genes: bla(CTX-M), bla(TEM), and bla(SHV). Furthermore, six of the E. coli ESβL isolated from faeces and carcasses swabs, were also able to produce biofilm, highlighting the virulence potential of these strains. The presence of Multi-Drug-Resistance patterns (MDR) recorded by the 73 ESβL E. coli was significant (60% of the strains were resistant to more than six antibiotics in MIC test). Results from the present study show that the transmission of resistant bacteria is possible along the food chain, including production of pork, one the most highly consumed meats around the world. Transmission is possible through the ingestion of raw meat products, and following cross-contamination between raw and cooked foods during preparation. The potential risk for human health demonstrated here, associated with the consumption of pork contaminated with bacterial strains characterized by multidrug resistance patterns, and the ability to produce ESβL and biofilm, is cause for concern. It is imperative to study future control strategies to avoid or limit as much as possible the transmission of these highly pathogenic strains through food consumption and/or contact with the environment.201930245289
161860.9999Molecular Characterization of Multidrug-Resistant Escherichia coli from Fecal Samples of Wild Animals. Antimicrobial resistance (AMR) surveillance in fecal Escherichia coli isolates from wildlife is crucial for monitoring the spread of this microorganism in the environment and for developing effective AMR control strategies. Wildlife can act as carriers of AMR bacteria and spread them to other wildlife, domestic animals, and humans; thus, they have public health implications. A total of 128 Escherichia coli isolates were obtained from 66 of 217 fecal samples obtained from different wild animals using media without antibiotic supplementation. Antibiograms were performed for 17 antibiotics to determine the phenotypic resistance profile in these isolates. Extended-spectrum β-lactamase (ESBL) production was tested using the double-disc synergy test, and 29 E. coli strains were selected for whole genome sequencing. In total, 22.1% of the wild animals tested carried multidrug-resistant E. coli isolates, and 0.93% (2/217) of these wild animals carried E. coli isolates with ESBL-encoding genes (bla(CTX-M-65), bla(CTX-M-55), and bla(EC-1982)). The E. coli isolates showed the highest resistance rates to ampicillin and were fully susceptible to amikacin, meropenem, ertapenem, and imipenem. Multiple resistance and virulence genes were detected, as well as different plasmids. The relatively high frequency of multidrug-resistant E. coli isolates in wildlife, with some of them being ESBL producers, raises some concern regarding the potential transmission of antibiotic-resistant bacteria among these animals. Gaining insights into antibiotic resistance patterns in wildlife can be vital in shaping conservation initiatives and developing effective strategies for responsible antibiotic use.202439453061
186370.9999Genomic surveillance of extended-spectrum cephalosporin-resistant Escherichia coli isolated from poultry in the UK from 2016 to 2020. INTRODUCTION: Surveillance is vital for monitoring the increasing risk of antimicrobial resistance (AMR) in bacteria leading to failures in humans and animals to treat infections. In a One Health context, AMR bacteria from livestock and food can transfer through the food chain to humans, and vice versa, which can be characterized in detail through genomics. We investigated the critical aspects of AMR and the dynamics of AMR in poultry in the UK. METHODS: In this study, we performed whole genome sequencing for genomic characterization of 761 extended-spectrum cephalosporinases (ESCs) harboring Escherichia coli isolated from poultry caeca and meat through EU harmonized monitoring of AMR in zoonotic and commensal bacteria from 2016 and 2018 and UK national monitoring in 2020. RESULTS: The most common ESC in 2016 and 2018 was blaCTX-M-1; however, 2020 had a greater diversity of ESCs with blaCTX-M-55 dominant in chickens and blaCTX-M-15 more prevalent in turkeys. Co-resistance to sulphonamides, tetracycline, and trimethoprim was widespread, and there were several positive correlations between the sequence types (STs) and ESC genes. We identified certain AMR genotypes and STs that were frequent each year but not as successful in subsequent years, e.g., ST350 harboring blaCTX-M-1, sul2, and tetA-v4.Phylogenetic comparison of isolates prevalent in our panel with global ones from the same STs available in public databases showed that isolates from the UK generally clustered together, suggesting greater within-country than between-country transmission. DISCUSSION: We conclude that future genomic surveillance of indicator organisms will be invaluable as it will enable detailed comparisons of AMR between and within neighboring countries, potentially identifying the most successful sequence types, plasmids, or emerging threats.202338352060
572980.9999Virulome and genome analyses identify associations between antimicrobial resistance genes and virulence factors in highly drug-resistant Escherichia coli isolated from veal calves. Food animals are known reservoirs of multidrug-resistant (MDR) Escherichia coli, but information regarding the factors influencing colonization by these organisms is lacking. Here we report the genomic analysis of 66 MDR E. coli isolates from non-redundant veal calf fecal samples. Genes conferring resistance to aminoglycosides, β-lactams, sulfonamides, and tetracyclines were the most frequent antimicrobial resistance genes (ARGs) detected and included those that confer resistance to clinically significant antibiotics (blaCMY-2, blaCTX-M, mph(A), erm(B), aac(6')Ib-cr, and qnrS1). Co-occurrence analyses indicated that multiple ARGs significantly co-occurred with each other, and with metal and biocide resistance genes (MRGs and BRGs). Genomic analysis also indicated that the MDR E. coli isolated from veal calves were highly diverse. The most frequently detected genotype was phylogroup A-ST Cplx 10. A high percentage of isolates (50%) were identified as sequence types that are the causative agents of extra-intestinal infections (ExPECs), such as ST69, ST410, ST117, ST88, ST617, ST648, ST10, ST58, and ST167, and an appreciable number of these isolates encoded virulence factors involved in the colonization and infection of the human urinary tract. There was a significant difference in the presence of multiple accessory virulence factors (VFs) between MDR and susceptible strains. VFs associated with enterohemorrhagic infections, such as stx, tir, and eae, were more likely to be harbored by antimicrobial-susceptible strains, while factors associated with extraintestinal infections such as the sit system, aerobactin, and pap fimbriae genes were more likely to be encoded in resistant strains. A comparative analysis of SNPs between strains indicated that several closely related strains were recovered from animals on different farms indicating the potential for resistant strains to circulate among farms. These results indicate that veal calves are a reservoir for a diverse group of MDR E. coli that harbor various resistance genes and virulence factors associated with human infections. Evidence of co-occurrence of ARGs with MRGs, BRGs, and iron-scavenging genes (sit and aerobactin) may lead to management strategies for reducing colonization of resistant bacteria in the calf gut.202235298535
204290.9999Genome Analysis of Multidrug-Resistant Escherichia coli Isolated from Poultry in Nigeria. Escherichia coli is one of the most common commensal bacteria of the gastrointestinal tract of humans and warm-blooded animals. Contaminated poultry can lead to disease outbreaks in consumers causing massive economic losses in the poultry industry. Additionally, commensal E. coli can harbor antibiotic resistance genes that can be transferred to other bacteria, including pathogens, in a colonized human host. In a previous study on antimicrobial resistance of E. coli from food animals from Nigeria, multidrug-resistant E. coli were detected. Three of those isolates were selected for further study using whole-genome sequencing due to the extensive drug resistance exhibited. All of the isolates carried the extended-spectrum β-lactamase (ESBL) genes, bla(CTX-M15) and bla(TEM-1), whereas one isolate harbored an additional ESBL, bla(OXA-1). All of the tetracycline-resistant isolates carried tet(A). The genes aac3-IIa and aacA4, conferring resistance to aminoglycosides, were identified in an E. coli isolate resistant to gentamicin and tobramycin. In two E. coli isolates, dfrA14, qnrS1, and sulII, were detected conferring resistance to trimethoprim, fluoroquinolones, and sulfonamides, respectively. The third isolate carried dfrA17, no fluoroquinolone resistance gene, an additional sulI gene, and a chloramphenicol resistance gene, catB3. Mutations in candidate genes conferring resistance to fosfomycin and fluoroquinolones were also detected. Several efflux systems were detected in all the E. coli isolates and virulence-associated genes related to serum resistance, motility, and adhesion. E. coli and non-E. coli origin prophages were also identified in the isolates. The results underline the higher resolution power of whole-genome sequencing for investigation of antimicrobial resistance, virulence, and phage in E. coli.202031509034
5567100.9999Comparison of Antibiotic Resistance and Virulence Factors among Escherichia coli Isolated from Conventional and Free-Range Poultry. Microbiological contamination in commercial poultry production has caused concerns for human health because of both the presence of pathogenic microorganisms and the increase in antimicrobial resistance in bacterial strains that can cause treatment failure of human infections. The aim of our study was to analyze the profile of antimicrobial resistance and virulence factors of E. coli isolates from chicken carcasses obtained from different farming systems (conventional and free-range poultry). A total of 156 E. coli strains were isolated and characterized for genes encoding virulence factors described in extraintestinal pathogenic E. coli (ExPEC). Antimicrobial susceptibility testing was performed for 15 antimicrobials, and strains were confirmed as extended spectrum of β-lactamases- (ESBLs-) producing E. coli by phenotypic and genotypic tests. The results indicated that strains from free-range poultry have fewer virulence factors than strains from conventional poultry. Strains from conventionally raised chickens had a higher frequency of antimicrobial resistance for all antibiotics tested and also exhibited genes encoding ESBL and AmpC, unlike free-range poultry isolates, which did not. Group 2 CTX-M and CIT were the most prevalent ESBL and AmpC genes, respectively. The farming systems of poultries can be related with the frequency of virulence factors and resistance to antimicrobials in bacteria.201526579536
1615110.9999Evaluation of the Antibiotic Resistance and Virulence of Escherichia coli Strains Isolated from Chicken Carcasses in 2007 and 2013 from Paraná, Brazil. The frequent use of antimicrobials in commercial poultry production has raised concerns regarding the potential impact of antimicrobials on human health due to selection for resistant bacteria. Several studies have reported similarities between extraintestinal pathogenic Escherichia coli (ExPEC) strains isolated from birds and humans, indicating that these contaminant bacteria in poultry may be linked to human disease. The aim of our study was to analyze the frequency of antimicrobial resistance and virulence factors among E. coli strains isolated from commercial chicken carcasses in Paraná, Brazil, in 2007 and 2013. A total of 84 E. coli strains were isolated from chicken carcasses in 2007, and 121 E. coli strains were isolated in 2013. Polymerase chain reaction was used to detect virulence genes (hlyF, iss, ompT, iron, and iutA) and to determine phylogenetic classification. Antimicrobial susceptibility testing was performed using 15 antimicrobials. The strains were also confirmed as extended-spectrum β-lactamase (ESBL)-producing E. coli with phenotypic and genotypic tests. The results indicated that our strains harbored virulence genes characteristic of ExPEC, with the iutA gene being the most prevalent. The phylogenetic groups D and B1 were the most prevalent among the strains isolated in 2007 and 2013, respectively. There was an increase in the frequency of resistance to a majority of antimicrobials tested. An important finding in this study was the large number of ESBL-producing E. coli strains isolated from chicken carcasses in 2013, primarily for the group 2 cefotaximase (CTX-M) enzyme. ESBL production confers broad-spectrum resistance and is a health risk because ESBL genes are transferable from food-producing animals to humans via poultry meat. These findings suggest that our strains harbored virulence and resistance genes, which are often associated with plasmids that can facilitate their transmission between bacteria derived from different hosts, suggesting zoonotic risks.201525974222
1594120.9998Production of extended-spectrum beta-lactamases in Escherichia coli isolated from poultry in Rio de Janeiro, Brazil. The overuse of antimicrobials in poultry has led to the development and dissemination of multidrug-resistant bacteria in the poultry industry. One of the most effective mechanisms of resistance found in Escherichia coli is the production of extended-spectrum β-lactamases (ESBL); there are several ESBLs, including the TEM, SHV, and CTX-M families. This resistance mechanism and the risks associated with transmitting these resistant microorganisms between animals, the environment, and humans can occur through direct contact and consumption of infected animals. This study aimed to determine the prevalence of E. coli in samples isolated from three broiler farms in Rio de Janeiro, Brazil, and screen the isolates for ESBL genes. The findings of this study demonstrated the presence of ESBL-producing E. coli in all farms studied. The findings of this study highlight the urgency for a program to monitor the poultry industry value chains at the regional level to control the spread of antimicrobial resistance. Therefore, we recommend that the enzyme subtypes produced by bacterial isolates should be determined to effectively characterize the distribution of genes related to antimicrobial resistance.202236533205
1653130.9998Resistance Genes, Plasmids, Multilocus Sequence Typing (MLST), and Phenotypic Resistance of Non-Typhoidal Salmonella (NTS) Isolated from Slaughtered Chickens in Burkina Faso. The emergence of antimicrobial-resistant bacteria in developing countries increases risks to the health of both such countries' residents and the global community due to international travel. It is consequently necessary to investigate antimicrobial-resistant pathogens in countries such as Burkina Faso, where surveillance data are not available. To study the epidemiology of antibiotic resistance in Salmonella, 102 Salmonella strains isolated from slaughtered chickens were subjected to whole-genome sequencing (WGS) to obtain information on antimicrobial resistance (AMR) genes and other genetic factors. Twenty-two different serotypes were identified using WGS, the most prevalent of which were Hato (28/102, 27.5%) and Derby (23/102, 22.5%). All strains analyzed possessed at least one and up to nine AMR genes, with the most prevalent being the non-functional aac(6')-Iaa gene, followed by aph(6)-Id. Multi-drug resistance was found genotypically in 36.2% of the isolates for different classes of antibiotics, such as fosfomycin and β-lactams, among others. Plasmids were identified in 43.1% of isolates (44/102), and 25 plasmids were confirmed to carry AMR genes. The results show that chicken can be considered as a reservoir of antibiotic-resistant Salmonella strains. Due to the prevalence of these drug-resistant pathogens and the potential for foodborne illnesses, poultry processing and cooking should be performed with attention to prescribed safe handling methods to avoid cross-contamination with chicken products.202235740187
5588140.9998Phenotypic and genotypic analyses of antimicrobial resistant bacteria in livestock in Uganda. Antimicrobial resistant bacteria (ARB) in livestock are a global public health concern, not only because they prolong infectious diseases but also they can be transferred from animals to humans via the food chain. Here, we studied ARB in livestock at commercial and subsistence farms (n = 13) in Wakiso and Mpigi districts, Uganda. We enquired from the farmers about the type and the purpose of antimicrobial agents they have used to treat their livestock. After collecting faeces, we isolated antimicrobial resistant Escherichia coli from livestock faeces (n = 134) as an indicator bacterium. These strains showed resistance to ampicillin (44.8%), tetracycline (97.0%), and sulfamethoxazole-trimethoprim (56.7%). The frequency of ampicillin-resistance was significantly correlated with the usage of penicillins to livestock in the farms (p = 0.04). The metagenomics data detected 911 antimicrobial resistant genes that were classified into 16 categories. Genes for multidrug efflux pumps were the most prevalent category in all except in one sample. Interestingly, the genes encoding third-generation cephalosporins (bla(CTX-M) ), carbapenems (bla(ACT) ), and colistin (arnA) were detected by metagenomics analysis although these phenotypes were not detected in our E. coli strains. Our results suggest that the emergence and transmission of cephalosporin, carbapenem, and/or colistin-resistant bacteria among livestock can occur in future if these antimicrobial agents are used.201930260584
2038150.9998Salmonella enterica Serotype 4,[5],12:i:- in Swine in the United States Midwest: An Emerging Multidrug-Resistant Clade. BACKGROUND: Salmonella 4,[5],12:i:-, a worldwide emerging pathogen that causes many food-borne outbreaks mostly attributed to pig and pig products, is expanding in the United States. METHODS: Whole-genome sequencing was applied to conduct multiple comparisons of 659 S. 4,[5],12:i:- and 325 Salmonella Typhimurium from different sources and locations (ie, the United States and Europe) to assess their genetic heterogeneity, with a focus on strains recovered from swine in the US Midwest. In addition, the presence of resistance genes and other virulence factors was detected and the antimicrobial resistance phenotypes of 50 and 22 isolates of livestock and human origin, respectively, was determined. RESULTS: The S. 4,5,12:i:- strains formed two main clades regardless of their source and geographic origin. Most (84%) of the US isolates recovered in 2014-2016, including those (48 of 51) recovered from swine in the US Midwest, were part of an emerging clade. In this clade, multiple genotypic resistance determinants were predominant, including resistance against ampicillin, streptomycin, sulfonamides, and tetracyclines. Phenotypic resistance to enrofloxacin (11 of 50) and ceftiofur (9 of 50) was found in conjunction with the presence of plasmid-mediated resistance genes (qnrB19/qnrB2/qnrS1 and blaCMY-2/blaSHV-12, respectively). Higher similarity was also found between S. 4,[5],12:i:- from the emerging clade and S. Typhimurium from Europe than with S. Typhimurium from the United States. CONCLUSIONS: Salmonella 4,[5],12:i:- currently circulating in swine in the US Midwest are likely to be part of an emerging multidrug-resistant clade first reported in Europe, and can carry plasmid-mediated resistance genes that may be transmitted horizontally to other bacteria, and thus may represent a public health concern.201829069323
1600160.9998Simultaneous Carriage of mcr-1 and Other Antimicrobial Resistance Determinants in Escherichia coli From Poultry. The use of antimicrobial growth promoters (AGPs) in sub-therapeutic doses for long periods promotes the selection of resistant microorganisms and the subsequent risk of spreading this resistance to the human population and the environment. Global concern about antimicrobial resistance development and transference of resistance genes from animal to human has been rising. The goal of our research was to evaluate the susceptibility pattern to different classes of antimicrobials of colistin-resistant Escherichia coli from poultry production systems that use AGPs, and characterize the resistance determinants associated to transferable platforms. E. coli strains (n = 41) were obtained from fecal samples collected from typical Argentine commercial broiler farms and susceptibility for 23 antimicrobials, relevant for human or veterinary medicine, was determined. Isolates were tested by PCR for the presence of mcr-1, extended spectrum β-lactamase encoding genes and plasmid-mediated quinolone resistance (PMQR) coding genes. Conjugation and susceptibility patterns of the transconjugant studies were performed. ERIC-PCR and REP-PCR analysis showed a high diversity of the isolates. Resistance to several antimicrobials was determined and all colistin-resistant isolates harbored the mcr-1 gene. CTX-M-2 cefotaximase was the main mechanism responsible for third generation cephalosporins resistance, and PMQR determinants were also identified. In addition, co-transference of the qnrB determinant on the mcr-1-positive transconjugants was corroborated, which suggests that these resistance genes are likely to be located in the same plasmid. In this work a wide range of antimicrobial resistance mechanisms were identified in E. coli strains isolated from the environment of healthy chickens highlighting the risk of antimicrobial abuse/misuse in animals under intensive production systems and its consequences for public health.201830090095
1948170.9998Identification and Characterization of Cefotaxime Resistant Bacteria in Beef Cattle. Third-generation cephalosporins are an important class of antibiotics that are widely used in treatment of serious Gram-negative bacterial infections. In this study, we report the isolation of bacteria resistant to the third-generation cephalosporin cefotaxime from cattle with no previous cefotaxime antibiotic exposure. The prevalence of cefotaxime-resistant bacteria was examined by a combination of culture based and molecular typing methods in beef cattle (n = 1341) from 8 herds located in North Central Florida. The overall prevalence of cefotaxime-resistant bacteria was 15.8% (95% CI: 13.9, 17.8), varied between farms, and ranged from 5.2% to 100%. A subset of isolates (n = 23) was further characterized for the cefotaxime minimum inhibitory concentration (MIC) and antibiotic susceptibility against 10 different antibiotics, sequencing of nine β- lactamase genes, and species identification by 16S rRNA sequencing. Most of the bacterial isolates were resistant to cefotaxime (concentrations, > 64 μg/mL) and showed high levels of multi-drug resistance. Full length 16S rRNA sequences (~1300 bp) revealed that most of the isolates were not primary human or animal pathogens; rather were more typical of commensal, soil, or other environmental origin. Six extended spectrum β-lactamase (ESBL) genes identical to those in clinical human isolates were identified. Our study highlights the potential for carriage of cefotaxime resistance (including "human" ESBL genes) by the bacterial flora of food animals with no history of cefotaxime antibiotic exposure. A better understanding of the origin and transmission of resistance genes in these pre-harvest settings will be critical to development of strategies to prevent the spread of antimicrobial resistant microorganisms to hospitals and communities.201627642751
5727180.9998Genetic mechanisms of antimicrobial resistance identified in Salmonella enterica, Escherichia coli, and Enteroccocus spp. isolated from U.S. food animals. The prevalence of antimicrobial resistance (AR) in bacteria isolated from U.S. food animals has increased over the last several decades as have concerns of AR foodborne zoonotic human infections. Resistance mechanisms identified in U.S. animal isolates of Salmonella enterica included resistance to aminoglycosides (e.g., alleles of aacC, aadA, aadB, ant, aphA, and StrAB), β-lactams (e.g., bla CMY-2, TEM-1, PSE-1), chloramphenicol (e.g., floR, cmlA, cat1, cat2), folate pathway inhibitors (e.g., alleles of sul and dfr), and tetracycline [e.g., alleles of tet(A), (B), (C), (D), (G), and tetR]. In the U.S., multi-drug resistance (MDR) mechanisms in Salmonella animal isolates were associated with integrons, or mobile genetic elements (MGEs) such as IncA/C plasmids which can be transferred among bacteria. It is thought that AR Salmonella originates in food animals and is transmitted through food to humans. However, some AR Salmonella isolated from humans in the U.S. have different AR elements than those isolated from food animals, suggesting a different etiology for some AR human infections. The AR mechanisms identified in isolates from outside the U.S. are also predominantly different. For example the extended spectrum β-lactamases (ESBLs) are found in human and animal isolates globally; however, in the U.S., ESBLs thus far have only been found in human and not food animal isolates. Commensal bacteria in animals including Escherichia coli and Enterococcus spp. may be reservoirs for AR mechanisms. Many of the AR genes and MGEs found in E. coli isolated from U.S. animals are similar to those found in Salmonella. Enterococcus spp. isolated from animals frequently carry MGEs with AR genes, including resistances to aminoglycosides (e.g., alleles of aac, ant, and aph), macrolides [e.g., erm(A), erm(B), and msrC], and tetracyclines [e.g., tet(K), (L), (M), (O), (S)]. Continuing investigations are required to help understand and mitigate the impact of AR bacteria on human and animal health.201323734150
2534190.9998Prevalence, antibiotic resistance, and virulence gene profile of Escherichia coli strains shared between food and other sources in Africa: A systematic review. BACKGROUND AND AIM: Foodborne diseases caused by Escherichia coli are prevalent globally. Treatment is challenging due to antibiotic resistance in bacteria, except for foodborne infections due to Shiga toxin-producing E. coli, for which treatment is symptomatic. Several studies have been conducted in Africa on antibiotic resistance of E. coli isolated from several sources. The prevalence and distribution of resistant pathogenic E. coli isolated from food, human, and animal sources and environmental samples and their virulence gene profiles were systematically reviewed. MATERIALS AND METHODS: Bibliographic searches were performed using four databases. Research articles published between 2000 and 2022 on antibiotic susceptibility and virulence gene profile of E. coli isolated from food and other sources were selected. RESULTS: In total, 64 articles were selected from 14 African countries: 45% of the studies were conducted on food, 34% on animal samples, 21% on human disease surveillance, and 13% on environmental samples. According to these studies, E. coli is resistant to ~50 antimicrobial agents, multidrug-resistant, and can transmit at least 37 types of virulence genes. Polymerase chain reaction was used to characterize E. coli and determine virulence genes. CONCLUSION: A significant variation in epidemiological data was noticed within countries, authors, and sources (settings). These results can be used as an updated database for monitoring E. coli resistance in Africa. More studies using state-of-the-art equipment are needed to determine all resistance and virulence genes in pathogenic E. coli isolated in Africa.202338023276