A study at the wildlife-livestock interface unveils the potential of feral swine as a reservoir for extended-spectrum β-lactamase-producing Escherichia coli. - Related Documents




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181701.0000A study at the wildlife-livestock interface unveils the potential of feral swine as a reservoir for extended-spectrum β-lactamase-producing Escherichia coli. Wildlife is known to serve as carriers and sources of antimicrobial resistance (AMR). Due to their unrestricted movements and behaviors, they can spread antimicrobial resistant bacteria among livestock, humans, and the environment, thereby accelerating the dissemination of AMR. Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is one of major concerns threatening human and animal health, yet transmission mechanisms at the wildlife-livestock interface are not well understood. Here, we investigated the mechanisms of ESBL-producing bacteria spreading across various hosts, including cattle, feral swine, and coyotes in the same habitat range, as well as from environmental samples over a two-year period. We report a notable prevalence and clonal dissemination of ESBL-producing E. coli in feral swine and coyotes, suggesting their persistence and adaptation within wildlife hosts. In addition, in silico studies showed that horizontal gene transfer, mediated by conjugative plasmids and insertion sequences elements, may play a key role in spreading the ESBL genes among these bacteria. Furthermore, the shared gut resistome of cattle and feral swine suggests the dissemination of antibiotic resistance genes at the wildlife-livestock interface. Taken together, our results suggest that feral swine may serve as a reservoir of ESBL-producing E. coli.202438788585
186510.9998Characterization of mobile resistance elements in extended-spectrum β-lactamase producing gram-negative bacteria from aquatic environment. Extended-spectrum β-lactamase producing (ESBL) bacteria from aquatic environments can pose potential threats to public health due to their capability of spreading antimicrobial resistance (AMR) genes through mobile genetic elements (MGEs), such as plasmids, insertion sequences (ISs), transposons, and integrons. Currently, there is no policy for routine monitoring of AMR genes in aquatic environments and their roles in transmission are therefore unknown. Previous metagenomic and PCR-based culture-independent approaches are limited in recovering AMR resistant aquatic bacteria isolates and the data resolution generated are not able to provide detailed genetic comparison with known human pathogens particularly for determining genetic islands harbouring AMR genes. To address these gaps, we thus investigated the genetic profiles of ESBL-producing gram-negative aquatic bacteria found from water body sites within Singapore, examining the AMR genes carried and their associated MGEs. In total, 16 ESBL-producing gram-negative bacteria were identified, of which 8 were Escherichia coli, 3 Klebsiella pneumoniae, and 5 Aeromonas spp. Whole genome sequencing (WGS) analysis revealed the presence of 12 distinct classes of AMR genes, including 16 distinct variants of β-lactamase, of which bla(CTX-M) was the dominant beta-lactamase genotype in all 11 Enterobacterales. The AMR genetic islands in the aquatic bacteria were also found to share similar genetic structures similar to those of circulating ESBL bacteria causing human infections. These findings underscore the potential role of aquatic ESBL bacteria as AMR reservoirs for human pathogens, suggesting that aquatic bacteria may facilitate the hidden transmission of AMR mediated by MGEs through horizontal gene transfer across different sources and species, highlighting the importance of integrating environmental AMR monitoring into local surveillance strategies.202540245502
186620.9997Drivers of the emergence and dissemination of high-risk resistance genes in cattle farm. Extended spectrum β-lactamase (ESBL)- and carbapenemase-producing Enterobacterales (CPE) are recognized by WHO as critical concerns. The high cephalosporin resistance rate in a cattle farm in 2018 prompted us to conduct long-term (2019-2023) and extensive monitoring to explore risk factors for the import and transmission of ESBLs and CPE in this farm. Among 1288 samples from cattle, the environment, milk, and biological vectors, 48.8 % carried bla(CTX-M)-positive Enterobacterales with bla(CTX-M-55) being dominant (76.4 %), and bla(NDM-5)-positive strains emerged in 2022 with a 1.9 % detection rate. bla(CTX-M-55) and bla(NDM-5) were likely introduced through various routes, especially wild birds, and have persisted due to overuse of cephalosporins in the farm. The spread of these genes was driven by the horizontal transmission of IncHI2 and IncX3 plasmids and clonal dissemination of certain clones. Cross-regional and cross-border transmission of bla(CTX-M-55)- and/or bla(NDM-5)-bearing bacteria and plasmids possibly occurred via wild birds, animal trade, and other means. Our findings suggest that the import, persistence, and dissemination of these genes within and beyond this farm, were fueled by suboptimal biosecurity practices and inadequate antibiotic stewardship, highlighting the urgency for integrated public and ecosystem health policies to prevent the spread of resistance genes as part of a holistic One Health strategy. ENVIRONMENTAL IMPLICATION: The high prevalence and long-term persistence of extended-spectrum β-lactamases and the emergence of carbapenemases in cattle and the environment signify a critical risk of transmitting high-risk resistance genes, posing a significant threat to human health. Consequently, bacteria carrying these genes in animal farms should be regarded as "hazardous materials". Import, persistence, and dissemination of these genes within and beyond this farm were exacerbated by suboptimal biosecurity practices and inadequate antibiotic stewardship, highlighting the urgency for integrated public and ecosystem health policies to mitigate the environmental risks associated with gene transmission as part of a comprehensive One Health strategy.202539899930
330730.9997Diversity of β-lactamase-encoding genes in wastewater: bacteriophages as reporters. A reservoir of antibiotic resistance genes (ARGs) is present in pathogenic, commensal, and environmental bacteria as well as in mobile genetic elements, including bacteriophages. Wastewater treatment plants (WWTPs) are considered hotspots for the spread of ARGs. The aim of this work was to analyze the diversity of the highly prevalent ARGs bla(CTX-M) and bla(TEM) in bacterial and bacteriophage fractions associated with human and animal environments through the study of urban waste and animal residues discharged into WWTPs to provide information about the composition and maintenance of the current resistome in Buenos Aires, Argentina. The results showed that a putative extended-spectrum variant of the bla(TEM) gene was the most frequently detected, with bla(TEM-116) being the most prevalent, while a recently described type, bla(TEM-229), was also found. In the bacteriophage fraction, we detected bla(CTX-M) genes from four out of the five clusters described. The detection of bla(CTX- M-9)-like and bla(CTX-M-25)-like genes was unexpected based on surveys of the ARGs from clinical pathogens circulating regionally. The finding of divergent bla(CTX-M) sequences associated with previously reported environmental genes argues in favor of the natural environment as a reservoir of resistance genes. ARGs were detected in bacteriophages as frequently as in bacterial communities, and furthermore, the bla(CTX-M) genes were more diverse in the bacteriophage fraction. Bacteriophages might therefore play a role in the spread of ARGs in the environment, but they might also be used as "reporters" for monitoring circulating ARGs.202133683473
159640.9997Distribution of bla(CTX-M-)gene variants in E. coli from different origins in Ecuador. The increasing abundance of extended spectrum (β-lactamase (ESBL) genes in E. coli, and other commensal and pathogenic bacteria, endangers the utility of third or more recent generation cephalosporins, which are major tools for fighting deadly infections. The role of domestic animals in the transmission of ESBL carrying bacteria has been recognized, especially in low- and middle-income countries, however the horizontal gene transfer of these genes is difficult to assess. Here we investigate bla(CTX-M) gene diversity (and flanking nucleotide sequences) in E. coli from chicken and humans, in an Ecuadorian rural community and from chickens in another location in Ecuador. The bla(CTX-M) associated sequences in isolates from humans and chickens in the same remote community showed greater similarity than those found in E. coli in a chicken industrial operation 200 km away. Our study may provide evidence of bla(CTX-M) transfer between chickens and humans in the community.202338148908
571850.9997A newly identified IncY plasmid from multi-drug-resistant Escherichia coli isolated from dairy cattle feces in Poland. Comprehensive whole-genome sequencing was performed on two multi-drug-resistant Escherichia coli strains isolated from cattle manure from a typical dairy farm in Poland in 2020. The identified strains are resistant to beta-lactams, aminoglycosides, tetracyclines, trimethoprim/sulfamethoxazole, and fluoroquinolones. The complete sequences of the harbored plasmids revealed antibiotic-resistance genes located within many mobile genetic elements (e.g., insertional sequences or transposons) and genes facilitating conjugal transfer or promoting horizontal gene transfer. These plasmids are hitherto undescribed. Similar plasmids have been identified, but not in Poland. The identified plasmids carried resistance genes, including the tetracycline resistance gene tet(A), aph family aminoglycoside resistance genes aph(3″)-lb and aph (6)-ld, beta-lactam resistance genes bla(TEM-1) and bla(CTX-M-15), sulfonamide resistance gene sul2, fluoroquinolone resistance gene qnrS1, and the trimethoprim resistance gene dfrA14. The characterized resistance plasmids were categorized into the IncY incompatibility group, indicating a high possibility for dissemination among the Enterobacteriaceae. While similar plasmids (99% identity) have been found in environmental and clinical samples, none have been identified in farm animals. These findings are significant within the One Health framework, as they underline the potential for antimicrobial-resistant E. coli from livestock and food sources to be transmitted to humans and vice versa. It highlights the need for careful monitoring and strategies to limit the spread of antibiotic resistance in the One Health approach. IMPORTANCE: This study reveals the identification of new strains of antibiotic-resistant Escherichia coli in cattle manure from a dairy farm in Poland, offering critical insights into the spread of drug resistance. Through whole-genome sequencing, researchers discovered novel plasmids within these bacteria, which carry genes resistant to multiple antibiotics. These findings are particularly alarming, as these plasmids can transfer between different bacterial species, potentially escalating the spread of antibiotic resistance. This research underscores the vital connection between the health of humans, animals, and the environment, emphasizing the concept of One Health. It points to the critical need for global vigilance and strategies to curb the proliferation of antibiotic resistance. By showcasing the presence of these strains and their advanced resistance mechanisms, the study calls for enhanced surveillance and preventive actions in both agricultural practices and healthcare settings to address the imminent challenge of antibiotic-resistant bacteria.202439012117
499360.9997The role of the natural aquatic environment in the dissemination of extended spectrum beta-lactamase and carbapenemase encoding genes: A scoping review. The natural aquatic environment is a significant contributor to the development and circulation of clinically significant antibiotic resistance genes (ARGs). The potential for the aquatic environment to act as a reservoir for ARG accumulation in areas receiving anthropogenic contamination has been thoroughly researched. However, the emergence of novel ARGs in the absence of external influences, as well as the capacity of environmental bacteria to disseminate ARGs via mobile genetic elements remain relatively unchallenged. In order to address these knowledge gaps, this scoping literature review was established focusing on the detection of two important and readily mobile ARGs, namely, extended spectrum beta-lactamase (ESBL) and carbapenemase genes. This review included 41 studies from 19 different countries. A range of different water bodies including rivers (n = 26), seawaters (n = 6) and lakes (n = 3), amongst others, were analysed in the included studies. ESBL genes were reported in 29/41 (70.7%) studies, while carbapenemase genes were reported in 13/41 (31.7%), including joint reporting in 9 studies. The occurrence of mobile genetic elements was evaluated, which included the detection of integrons (n = 22), plasmids (n = 18), insertion sequences (n = 4) and transposons (n = 3). The ability of environmental bacteria to successfully transfer resistance genes via conjugation was also examined in 11 of the included studies. The findings of this scoping review expose the presence of clinically significant ARGs in the natural aquatic environment and highlights the potential ability of environmental isolates to disseminate these genes among different bacterial species. As such, the results presented demonstrate how anthropogenic point discharges may not act as the sole contributor to the development and spread of clinically significant antibiotic resistances. A number of critical knowledge gaps in current research were also identified. Key highlights include the limited number of studies focusing on antibiotic resistance in uncontaminated aquatic environments as well as the lack of standardisation among methodologies of reviewed investigations.202032438141
500970.9997Types and prevalence of extended-spectrum beta-lactamase producing Enterobacteriaceae in poultry. For several billion years, bacteria have developed mechanisms to resist antibacterial substances. In modern time, antibiotics are frequently used in veterinary and human medicine for prevention and treatment of diseases, globally still also for their growth promoting effects as feed additives. This complex situation has evolved in accelerating development and prevalence of multi-drug resistant bacteria in livestock and people. Extended-spectrum beta-lactamase (ESBL) producing bacteria are resistant to a wide range of ß-lactam antibiotics. They are currently considered as one of the main threats for the treatment of infections in humans and animals. In livestock and animal products, poultry and poultry products show the highest prevalence of ESBL-producers with CTX-M-1, TEM-52 and SHV-12 being the most common ESBL-types in poultry. Escherichia coli and Salmonella spp. are the bacteria in poultry, which carry ESBL-genes most frequently. ESBL-producing bacteria are present at every level of the poultry production pyramid and can be detected even in the meconium of newly hatched chicks. The environment close to poultry barns shows high prevalence rates of these bacteria and contributes to an ongoing infection pressure with further ESBL-types. Probiotics have been shown to successfully reduce ESBL-producers in chicken, as well as ESBL-gene transfer. Other feed additives, such as zinc and copper, increase the prevalence of ESBL-producing bacteria when fed to animals. To our best knowledge, this is the first publication presenting a comparative overview of the prevalence of ESBL-types using data from different countries. To reduce the hazard for public health from poultry carrying high numbers of ESBL-producers, preventive measurements must include the surrounding environment and avoidance of antibiotic usage at all levels of the production pyramid. The first results, of the research on the impact of feed additives on the spread of ESBL-genes, indicate the diet as a further, possible magnitude of influence.201728641596
499680.9997Antimicrobial resistance of Escherichia coli isolated from fish and aquaculture water: an emerging concern for consumers. Antimicrobial resistance (AMR) constitutes a significant global health threat, exacerbated using antimicrobials in aquaculture, which accelerates the spread of resistant bacteria. In fish and aquaculture water, Escherichia coli acts as a key reservoir and vector for AMR, facilitating the dissemination of strains resistant to critically important antibiotics such as carbapenems and colistin, often through the production of enzymes such as extended-spectrum ß-lactamases. This review aimed to synthesize recent findings on AMR patterns and associated genes in E. coli from fish and aquaculture waters globally. Studies indicate a high prevalence of resistant E. coli, with multidrug resistance to β-lactams, tetracyclines, quinolones, and sulfonamides. Common resistance genes identified include blaTEM, blaCTX-M, tet(A), sul1, and qnrS. The presence of bacterial strains harboring these resistance genes poses a significant public health risk through transmission in the food chain and the environment. The study concludes that tackling this challenge effectively demands robust surveillance, optimized aquaculture management, responsible antimicrobial stewardship, and a cohesive One Health framework aimed at reducing AMR in aquaculture and preserving public health.202540693960
501090.9997Carbapenemase-producing bacteria in food-producing animals, wildlife and environment: A challenge for human health. Antimicrobial resistance is an increasing global health problem and one of the major concerns for economic impacts worldwide. Recently, resistance against carbapenems (doripenem, ertapenem, imipenem, meropenem), which are critically important antimicrobials for human cares, poses a great risk all over the world. Carbapenemases are β-lactamases belonging to different Ambler classes (A, B, D) and encoded by both chromosomal and plasmidic genes. They hydrolyze a broad variety of β-lactams, including carbapenems, cephalosporins, penicillins and aztreonam. Despite several studies in human patients and hospital settings have been performed in European countries, the role of livestock animals, wild animals and the terrestrial and aquatic environment in the maintenance and transmission of carbapenemase- producing bacteria has been poorly investigated. The present review focuses on the carbapenemase-producing bacteria detected in pigs, cattle, poultry, fish, mollusks, wild birds and wild mammals in Europe as well as in non-European countries, investigating the genetic mechanisms for their transmission among food-producing animals and wildlife. To shed light on the important role of the environment in the maintenance and genetic exchange of resistance determinants between environmental and pathogenic bacteria, studies on aquatic sources (rivers, lakes, as well as wastewater treatment plants) are described.201931316921
1864100.9997Colonization of White-Tailed Deer (Odocoileus virginianus) from Urban and Suburban Environments with Cephalosporinase- and Carbapenemase-Producing Enterobacterales. Wildlife play a role in the acquisition, maintenance, and dissemination of antimicrobial resistance (AMR). This is especially true at the human-domestic animal-wildlife interface, like urbanized areas, where interactions occur that can promote the cross-over of AMR bacteria and genes. We conducted a 2-year fecal surveillance (n = 783) of a white-tailed deer (WTD) herd from an urban park system in Ohio to identify and characterize cephalosporin-resistant and carbapenemase-producing bacteria using selective enrichment. Using generalized linear mixed models we found that older (OR = 2.3, P < 0.001), male (OR = 1.8, P = 0.001) deer from urbanized habitats (OR = 1.4, P = 0.001) were more likely to harbor extended-spectrum cephalosporin-resistant Enterobacterales. In addition, we isolated two carbapenemase-producing Enterobacterales (CPE), a Klebsiella quasipneumoniae harboring bla(KPC-2) and an Escherichia coli harboring bla(NDM-5), from two deer from urban habitats. The genetic landscape of the plasmid carrying bla(KPC-2) was unique, not clustering with other reported plasmids encoding KPC-2, and only sharing 78% of its sequence with its nearest match. While the plasmid carrying bla(NDM-5) shared sequence similarity with other reported plasmids encoding NDM-5, the intact IS26 mobile genetic elements surrounding multiple drug resistant regions, including the bla(NDM-5), has been reported infrequently. Both carbapenemase genes were successfully conjugated to a J53 recipient conferring a carbapenem-resistant phenotype. Our findings highlight that urban environments play a significant role on the transmission of AMR bacteria and genes to wildlife and suggest WTD may play a role in the dissemination of clinically and epidemiologically relevant antimicrobial resistant bacteria. IMPORTANCE The role of wildlife in the spread of antimicrobial resistance is not fully characterized. Some wildlife, including white-tailed deer (WTD), can thrive in suburban and urban environments. This may result in the exchange of antimicrobial resistant bacteria and resistance genes between humans and wildlife, and lead to their spread in the environment. We found that WTD living in an urban park system carried antimicrobial resistant bacteria that were important to human health and resistant to antibiotics used to treat serious bacterial infections. This included two deer that carried bacteria resistant to carbapenem antibiotics which are critically important for treatment of life-threatening infections. These two bacteria had the ability to transfer their AMR resistance genes to other bacteria, making them a threat to public health. Our results suggest that WTD may contribute to the spread of antimicrobial resistant bacteria in the environment.202235736227
5006110.9997Genomic insights of mcr-1 harboring Escherichia coli by geographical region and a One-Health perspective. The importance of the One Health concept in attempting to deal with the increasing levels of multidrug-resistant bacteria in both human and animal health is a challenge for the scientific community, policymakers, and the industry. The discovery of the plasmid-borne mobile colistin resistance (mcr) in 2015 poses a significant threat because of the ability of these plasmids to move between different bacterial species through horizontal gene transfer. In light of these findings, the World Health Organization (WHO) recommends that countries implement surveillance strategies to detect the presence of plasmid-mediated colistin-resistant microorganisms and take suitable measures to control and prevent their dissemination. Seven years later, ten different variants of the mcr gene (mcr-1 to mcr-10) have been detected worldwide in bacteria isolated from humans, animals, foods, the environment, and farms. However, the possible transmission mechanisms of the mcr gene among isolates from different geographical origins and sources are largely unknown. This article presents an analysis of whole-genome sequences of Escherichia coli that harbor mcr-1 gene from different origins (human, animal, food, or environment) and geographical location, to identify specific patterns related to virulence genes, plasmid content and antibiotic resistance genes, as well as their phylogeny and their distribution with their origin. In general, E. coli isolates that harbor mcr-1 showed a wide plethora of ARGs. Regarding the plasmid content, the highest concentration of plasmids was found in animal samples. In turn, Asia was the continent that led with the largest diversity and occurrence of these plasmids. Finally, about virulence genes, terC, gad, and traT represent the most frequent virulence genes detected. These findings highlight the relevance of analyzing the environmental settings as an integrative part of the surveillance programs to understand the origins and dissemination of antimicrobial resistance.202236726572
2577120.9997Molecular Detection of bla(TEM) and bla(SHV) Genes in ESBL-Producing Acinetobacter baumannii Isolated from Antarctic Soil. The phenomenon of antimicrobial resistance (AMR) in cold environments, exemplified by the Antarctic, calls into question the assumption that pristine ecosystems lack clinically significant resistance genes. This study examines the molecular basis of AMR in Acinetobacter spp. Isolated from Antarctic soil, focusing on the bla(TEM) and bla(SHV) genes associated with extended-spectrum beta-lactamase (ESBL) production; Soil samples were collected and processed to isolate Antarctic soil bacteria. Molecular detection was then conducted using polymerase chain reaction (PCR) to identify the bacteria species by 16S rRNA/rpoB and 10 different beta-lactamase-producing genes. PCR amplicons were sequenced to confirm gene identity and analyze genetic variability. Acinetobacter baumannii were identified by both microbiological and molecular tests. Notably, both the bla(TEM) and bla(SHV) genes encoding the enzymes responsible for resistance to penicillins and cephalosporins were identified, indicating the presence of resistance determinants in bacteria from extreme cold ecosystems. The nucleotide sequence analysis indicated the presence of conserved ARGs, which suggest stability and the potential for horizontal gene transfer within microbial communities. These findings emphasize that AMR is not confined to human-impacted environments but can emerge and persist in remote, cold habitats, potentially facilitated by natural reservoirs and global microbial dispersal. Understanding the presence and role of AMR in extreme environments provides insights into its global dissemination and supports the development of strategies to mitigate the spread of resistance genes in both environmental and clinical contexts.202540142377
5016130.9997Broad-spectrum β-lactamases among Enterobacteriaceae of animal origin: molecular aspects, mobility and impact on public health. Broad-spectrum β-lactamase genes (coding for extended-spectrum β-lactamases and AmpC β-lactamases) have been frequently demonstrated in the microbiota of food-producing animals. This may pose a human health hazard as these genes may be present in zoonotic bacteria, which would cause a direct problem. They can also be present in commensals, which may act as a reservoir of resistance genes for pathogens causing disease both in humans and in animals. Broad-spectrum β-lactamase genes are frequently located on mobile genetic elements, such as plasmids, transposons and integrons, which often also carry additional resistance genes. This could limit treatment options for infections caused by broad-spectrum β-lactam-resistant microorganisms. This review addresses the growing burden of broad-spectrum β-lactam resistance among Enterobacteriaceae isolated from food, companion and wild animals worldwide. To explore the human health hazard, the diversity of broad-spectrum β-lactamases among Enterobacteriaceae derived from animals is compared with respect to their presence in human bacteria. Furthermore, the possibilities of the exchange of genes encoding broad-spectrum β-lactamases - including the exchange of the transposons and plasmids that serve as vehicles for these genes - between different ecosystems (human and animal) are discussed.201020030731
5003140.9997Updates on the global dissemination of colistin-resistant Escherichia coli: An emerging threat to public health. Colistin drug resistance is an emerging public health threat worldwide. The adaptability, existence and spread of colistin drug resistance in multiple reservoirs and ecological environmental settings is significantly increasing the rate of occurrence of multidrug resistant (MDR) bacteria such as Escherichia coli (E. coli). Here, we summarized the reports regarding molecular and biological characterization of mobile colistin resistance gene (mcr)-positive E. coli (MCRPEC), originating from diverse reservoirs, including but not limited to humans, environment, waste water treatment plants, wild, pets, and food producing animals. The MCRPEC revealed the abundance of clinically important resistance genes, which are responsible for MDR profile. A number of plasmid replicon types such as IncI2, IncX4, IncP, IncX, and IncFII with a predominance of IncI2 were facilitating the spread of colistin resistance. This study concludes the distribution of multiple sequence types of E. coli carrying mcr gene variants, which are possible threat to "One Health" perspective. In addition, we have briefly explained the newly known mechanisms of colistin resistance i.e. plasmid-encoded resistance determinant as well as presented the chromosomally-encoded resistance mechanisms. The transposition of ISApl1 into the chromosome and existence of intact Tn6330 are important for transmission and stability for mcr gene. Further, genetic environment of co-localized mcr gene with carbapenem-resistance or extended-spectrum β-lactamases genes has also been elaborated, which is limiting human beings to choose last resort antibiotics. Finally, environmental health and safety control measures along with spread mechanisms of mcr genes are discussed to avoid further propagation and environmental hazards of colistin resistance.202134364270
5717150.9997Introduction of the transmissible mobile colistin resistance genes mcr-3 and mcr-9 to the USA via imported seafood. The emergence and global dissemination of the mobile colistin resistance genes (mcr) threaten the efficacy of colistin, a high-priority, critically important antibiotic that is used to treat complicated infections with multidrug-resistant Gram-negative bacteria in humans. The occurrence of mcr in the USA has been suggested to be relatively limited, particularly in bacteria associated with domestic foods and food animals. This is because colistin has neither been marketed nor approved for use in agriculture in the USA. However, mcr-carrying bacteria can occur on foods imported from countries where these genes might be relatively more prevalent. Yet, studies on mcr in vulnerable imported foods in the USA are lacking. To address this gap in knowledge, we assessed the role of imported seafood as a potential carrier of mcr genes to the USA. Imported seafood samples were aseptically collected from eight major retail stores across Georgia, USA. In-depth analyses revealed the occurrence of mcr-9 in bacteria isolated from imported shrimp samples. The mcr-9-carrying bacteria were identified as Serratia nevei, a newly described species that belongs to the Serratia marcescens complex. The mcr-9 in the S. nevei isolates was carried on IncHI2 plasmids that were transferable and conferred colistin resistance to naïve Escherichia coli. Further analysis identified a chromosomal mcr-3.17 in Aeromonas salmonicida isolated from imported scallops. All the mcr-carrying isolates harbored other important antibiotic resistance genes. Taken together, our data showed that imported seafood, specifically shrimps, might be an overlooked source contributing to the introduction and spread of transmissible colistin resistance genes in the USA. IMPORTANCE: Colistin, an important antibiotic, is used to treat certain bacterial infections in humans that can be severe and/or life-threatening. However, these bacteria can acquire the mobile colistin resistance (mcr) genes and become resistant to this antibiotic. Plasmid-borne mcr can jump between bacterial species, spreading in bacteria across a variety of hosts and niches. Therefore, monitoring the spread of mcr is critical to maintain the efficacy of colistin. In the USA, the occurrence of mcr in domestically produced food is thought to be limited. In this study, we showed that mcr can be carried into the USA by bacteria on imported seafood. A specific gene, mcr-9, was located on a plasmid that could be transferred to other bacteria. Therefore, imported seafood can be an overlooked source of mcr in the USA. It is important to monitor and assess mcr in imported seafood to control the proliferation of colistin resistance in the USA.202540622135
2562160.9997Characterisation of Antimicrobial Resistance in Special-Fed Veal Production Environments. INTRODUCTION: Antimicrobial resistance (AMR) is one of the leading public health threats globally. AMR genes can be transferred between bacteria through lateral gene transfer, and AMR organisms can spread through environments by contaminated water, agriculture and animals. Thus, widespread environmental dissemination of bacteria and lateral gene transfer facilitate AMR transmission pathways. Farm environments in dairy and calf production are known to harbour AMR bacteria that pose a risk for food contamination and to workers in direct or indirect contact with animals. Escherichia coli is present in farm environments and is known to participate in lateral gene transfer, providing a good marker of resistance genes in each environment. METHODS: In this study, E. coli from nine cohorts of calves was isolated at different time points from nine barns, nine trailers and one slaughterhouse environment in a single special-fed veal calf production facility. The antimicrobial susceptibility to 15 antimicrobials, classified as highly or critically important by the World Health Organization, was characterised for E. coli isolates using Kirby-Bauer disk diffusion. RESULTS: The highest proportion of isolates showing multidrug resistance was present in barn environments (51.7%), where calves were housed from their arrival at < 2 weeks of age until they were transported to slaughter. Additionally, 15 E. coli isolates were resistant to 11 of the 15 antimicrobials tested. Trailer and slaughterhouse environments had greater prevalence of resistance after accommodating calves, including resistance to third-generation cephalosporins. CONCLUSION: These data highlight the importance of calf environments in the dissemination of resistant bacteria and gives insight into where interventions could be most effective in combatting antimicrobial-resistant bacteria that could infect humans and livestock.202539402773
2836170.9996Waste water effluent contributes to the dissemination of CTX-M-15 in the natural environment. OBJECTIVES: Multidrug-resistant Enterobacteriaceae pose a significant threat to public health. We aimed to study the impact of sewage treatment effluent on antibiotic resistance reservoirs in a river. METHODS: River sediment samples were taken from downstream and upstream of a waste water treatment plant (WWTP) in 2009 and 2011. Third-generation cephalosporin (3GC)-resistant Enterobacteriaceae were enumerated. PCR-based techniques were used to elucidate mechanisms of resistance, with a new two-step PCR-based assay developed to investigate bla(CTX-M-15) mobilization. Conjugation experiments and incompatibility replicon typing were used to investigate plasmid ecology. RESULTS: We report the first examples of bla(CTX-M-15) in UK river sediment; the prevalence of bla(CTX-M-15) was dramatically increased downstream of the WWTP. Ten novel genetic contexts for this gene were identified, carried in pathogens such as Escherichia coli ST131 as well as indigenous aquatic bacteria such as Aeromonas media. The bla(CTX-M-15) -gene was readily transferable to other Gram-negative bacteria. We also report the first finding of an imipenem-resistant E. coli in a UK river. CONCLUSIONS: The high diversity and host range of novel genetic contexts proves that evolution of novel combinations of resistance genes is occurring at high frequency and has to date been significantly underestimated. We have identified a worrying reservoir of highly resistant enteric bacteria in the environment that poses a threat to human and animal health.201424797064
5724180.9996Convergence of virulence and resistance in international clones of WHO critical priority enterobacterales isolated from Marine Bivalves. The global spread of critical-priority antimicrobial-resistant Enterobacterales by food is a public health problem. Wild-caught seafood are broadly consumed worldwide, but exposure to land-based pollution can favor their contamination by clinically relevant antimicrobial-resistant bacteria. As part of the Grand Challenges Explorations: New Approaches to Characterize the Global Burden of Antimicrobial Resistance Program, we performed genomic surveillance and cell culture-based virulence investigation of WHO critical priority Enterobacterales isolated from marine bivalves collected in the Atlantic Coast of South America. Broad-spectrum cephalosporin-resistant Klebsiella pneumoniae and Escherichia coli isolates were recovered from eight distinct geographical locations. These strains harbored bla(CTX-M)-type or bla(CMY)-type genes. Most of the surveyed genomes confirmed the convergence of wide virulome and resistome (i.e., antimicrobials, heavy metals, biocides, and pesticides resistance). We identified strains belonging to the international high-risk clones K. pneumoniae ST307 and E. coli ST131 carrying important virulence genes, whereas in vitro experiments confirmed the high virulence potential of these strains. Thermolabile and thermostable toxins were identified in some strains, and all of them were biofilm producers. These data point to an alarming presence of resistance and virulence genes in marine environments, which may favor horizontal gene transfer and the spread of these traits to other bacterial species.202235383231
2563190.9996Dissemination of Resistant Escherichia coli Among Wild Birds, Rodents, Flies, and Calves on Dairy Farms. Antimicrobial resistance (AMR) in bacteria in the livestock is a growing problem, partly due to inappropriate use of antimicrobial drugs. Antimicrobial use (AMU) occurs in Swedish dairy farming but is restricted to the treatment of sick animals based on prescription by a veterinary practitioner. Despite these strict rules, calves shedding antimicrobial resistant Enterobacteriaceae have been recorded both in dairy farms and in slaughterhouses. Yet, not much is known how these bacteria disseminate into the local environment around dairy farms. In this study, we collected samples from four animal sources (fecal samples from calves, birds and rodents, and whole flies) and two environmental sources (cow manure drains and manure pits). From the samples, Escherichia coli was isolated and antimicrobial susceptibility testing performed. A subset of isolates was whole genome sequenced to evaluate relatedness between sources and genomic determinants such as antimicrobial resistance genes (ARGs) and the presence of plasmids were assessed. We detected both ARGs, mobile genetic elements and low rates of AMR. In particular, we observed four potential instances of bacterial clonal sharing in two different animal sources. This demonstrates resistant E. coli dissemination potential within the dairy farm, between calves and scavenger animals (rodents and flies). AMR dissemination and the zoonotic AMR risk is generally low in countries with low and restricted AMU. However, we show that interspecies dissemination does occur, and in countries that have little to no AMU restrictions this risk could be under-estimated.202235432261