Reservoir Of Antimicrobial-resistant Bacteria Research Articles

Private and well drinking water are reservoirs for antimicrobial resistant bacteria

Water quality testing does not recognise antimicrobial resistance (AMR) and is often limited to indicators of faecal contamination Escherichia coli and Enterococcus species. In Europe, data on AMR in drinking water is scarce. In Ireland, as in many countries, household drinking water is supplied via mains or via private wells or water schemes. Using citizen science, we identified Irish private drinking water supplies as reservoirs of antimicrobial resistant bacteria (ARB). Gram-negative (n = 464) and Gram-positive (n = 72) bacteria were isolated. We identified instances of potentially opportunistic ARB such as Enterobacter cloacae, Acinetobacter baumannii and Enterococcus species. We report reservoirs of multidrug resistance in Enterococcus casseliflavus, E. cloacae, E. coli, Stenotrophomonas maltophilia, and Serratia rubidaea. We also identified linezolid-resistant Enterococcus in Irish drinking water. Linezolid is a last-resort antibiotic used to treat vancomycin-resistant Enterococcus sp. Additionally, we identified mobile AMR in three water samples, two of which were carried on IncF group, one on IncQ and five on Col-like plasmids. Our work suggests that private drinking water is a potential sink and source of AMR pathogens. This highlights a value of drinking water surveillance in a One Health framework as the surveillance would provide information regarding the movement and persistence of ARB and ARGs that are able to survive in drinking water and subsequently have the opportunity to be mobilised through humans; linking the environment to the human and potentially threatening human health.

Genome-Wide Analysis of Escherichia coli Isolated from Dairy Animals Identifies Virulence Factors and Genes Enriched in Multidrug-Resistant Strains.

The gastrointestinal tracts of dairy calves and cows are reservoirs of antimicrobial-resistant bacteria (ARB), which are present regardless of previous antimicrobial therapy. Young calves harbor a greater abundance of resistant bacteria than older cows, but the factors driving this high abundance are unknown. Here, we aimed to fully characterize the genomes of multidrug-resistant (MDR) and antimicrobial-susceptible Escherichia coli strains isolated from pre-weaned calves, post-weaned calves, dry cows, and lactating cows and to identify the accessory genes that are associated with the MDR genotype to discover genetic targets that can be exploited to mitigate antimicrobial resistance in dairy farms. Results indicated that both susceptible and resistant E. coli isolates recovered from animals on commercial dairy operations were highly diverse and encoded a large pool of virulence factors. In total, 838 transferrable antimicrobial resistance genes (ARGs) were detected, with genes conferring resistance to aminoglycosides being the most common. Multiple sequence types (STs) associated with mild to severe human gastrointestinal and extraintestinal infections were identified. A Fisher's Exact Test identified 619 genes (ARGs and non-ARGs) that were significantly enriched in MDR isolates and 147 genes that were significantly enriched in susceptible isolates. Significantly enriched genes in MDR isolates included the iron scavenging aerobactin synthesis and receptor genes (iucABCD-iutA) and the sitABCD system, as well as the P fimbriae pap genes, myo-inositol catabolism (iolABCDEG-iatA), and ascorbate transport genes (ulaABC). The results of this study demonstrate a highly diverse population of E. coli in commercial dairy operations, some of which encode virulence genes responsible for severe human infections and resistance to antibiotics of human health significance. Further, the enriched accessory genes in MDR isolates (aerobactin, sit, P fimbriae, and myo-inositol catabolism and ascorbate transport genes) represent potential targets for reducing colonization of antimicrobial-resistant bacteria in the calf gut.

Antimicrobial-Resistant Enterobacterales Recovered from the Environment of Two Zoological Institutions Include Enterobacter cloacae Complex ST171 Producing KPC-4 Carbapenemase.

Environmental surfaces can serve as reservoirs for pathogens and antimicrobial-resistant (AMR) bacteria in healthcare settings. Although active surveillance programs are used in veterinary and human healthcare, unconventional settings like zoological facilities are often overlooked, even though antimicrobials are used to maintain the health of their animal collections. Here, we used electrostatic cloths to conduct active environmental surveillance over a 2-year period at two zoological institutions to determine contamination prevalence of human-only and mixed animal-human touch environments with AMR bacteria. We recovered Enterobacterales isolates that expressed quinolone resistance, an AmpC-like phenotype, and an extended-spectrum β-lactamase phenotype from 144 (39%), 141 (38.2%), and 72 (19.5%) of the environmental samples, respectively. The zoological institutions, areas and exhibits within the zoological facility, and sampling surface type affected the odds of recovering AMR bacteria from the environment. Three carbapenemase-producing Enterobacter cloacae complex ST171 isolates recovered from one zoological facility harbored an IncH12 plasmid with a Tn4401b-KPC-4 transposon conferring multidrug resistance. One isolate maintained three tandem repeats of a Tn4401b-KPC-4 element on an IncHI2 plasmid, although this isolate was susceptible to the four carbapenem drugs tested. These three isolates and their IncH12 plasmids shared significant genomic similarity with two E. cloacae complex isolates recovered from canine patients at a regional veterinary hospital during year 2 of this study. Our results indicated that surface environments at zoological institutions can serve as reservoirs for AMR bacteria and their genes and have implications for animal and public health. IMPORTANCE Environmental surfaces can be a source of antimicrobial-resistant (AMR) bacteria that pose a risk to human and animal health. Zoological institutions are unique environments where exotic animals, staff, and visitors intermingle and antimicrobials are used to maintain animal health. However, zoological environments are often overlooked as reservoirs of AMR bacteria. Here, we show that zoological environments can serve as reservoirs of fluoroquinolone-resistant and extended-spectrum cephalosporin-resistant bacteria. In addition, we isolated three carbapenemase-producing Enterobacter cloacae complex strains carrying blaKPC-4, including one with a unique, tandem triplicate of the Tn4401b-KPC-4 element. Comparative whole genomics of these isolates with two E. cloacae complex isolates from patients at a regional veterinary hospital highlighted the possibility of local KPC-4 spread between animal environments. Our results suggest that environments at zoological institutions serve as reservoirs for AMR bacteria and pose a hypothetical One Health risk to the public, staff, and the wild animal populations in captivity.

Trophic level and proteobacteria abundance drive antibiotic resistance levels in fish from coastal New England

BackgroundThe natural marine environment represents a vast reservoir of antimicrobial resistant bacteria. The wildlife that inhabits this environment plays an important role as the host to these bacteria and in the dissemination of resistance. The relationship between host diet, phylogeny, and trophic level and the microbiome/resistome in marine fish is not fully understood. To further explore this relationship, we utilize shotgun metagenomic sequencing to define the gastrointestinal tract microbiomes of seven different marine vertebrates collected in coastal New England waters.ResultsWe identify inter and intraspecies differences in the gut microbiota of these wild marine fish populations. Furthermore, we find an association between antibiotic resistance genes and host dietary guild, which suggests that higher trophic level organisms have a greater abundance of resistance genes. Additionally, we demonstrate that antibiotic resistance gene burden is positively correlated with Proteobacteria abundance in the microbiome. Lastly, we identify dietary signatures within the gut of these fish and find evidence of possible dietary selection for bacteria with specific carbohydrate utilization potential.ConclusionsThis work establishes a link between host lifestyle/dietary guild, and microbiome composition and the abundance of antibiotic resistance genes within the gastrointestinal tract of marine organisms. We expand the current understanding of marine organism-associated microbial communities and their role as reservoirs of antimicrobial resistance genes.

High Prevalence of bla CTXM-1/IncI1-Iγ/ST3 Plasmids in Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolates Collected From Domestic Animals in Guadeloupe (French West Indies).

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) have been classified in the group of resistant bacteria of highest priority. We determined the prevalence of ESBL-E collected in feces from household and shelter pets in Guadeloupe (French West Indies). A single rectal swab was taken from 125 dogs and 60 cats between June and September 2019. The prevalence of fecal carriage of ESBL-E was 7.6% (14/185, 95% CI: 4.2-12.4), within the range observed worldwide. The only risk factor associated with a higher prevalence of ESBL-E rectal carriage was a stay in a shelter, suggesting that refuges could be hotspots for their acquisition. All but one (Klebsiella pneumoniae from a cat) were Escherichia coli. We noted the presence of a blaCTX–M–1/IncI1-Iγ/sequence type (ST3) plasmid in 11 ESBL-producing E. coli isolates belonging to ST328 (n = 6), ST155 (n = 4) and ST953 (n = 1). A blaCTX–M–15 gene was identified in the three remaining ESBL-E isolates. The blaCTX–M–1 and most of the antimicrobial resistance genes were present in a well-conserved large conjugative IncI1-Iγ/ST3 plasmid characterized by two accessory regions containing antibiotic resistance genes. The plasmid has been detected worldwide in E. coli isolates from humans and several animal species, such as food-producing animals, wild birds and pets, and from the environment. This study shows the potential role of pets as a reservoir of antimicrobial-resistant bacteria or genes for humans and underlines the importance of basic hygiene measures by owners of companion animals.

Infiltration of hidden antimicrobial resistance among healthy people in a Japanese community.

BackgroundUnder non-antimicrobial selective pressure, antimicrobial-resistant bacteria do not easily become dominant in the microbiota. Furthermore, their low levels prevent detection by isolation, resulting in an underestimation of the prevalence of antimicrobial-resistant bacteria.ObjectivesWe evaluated the infiltration of antimicrobial-resistant bacteria and their related β-lactamase genes among healthy people in non-clinical settings.MethodsCephalosporin- and fluoroquinolone-resistant Escherichia coli and bla genes were quantified in 217 faecal samples from healthy people in non-clinical settings in Japan. E. coli colonies grown on deoxycholate hydrogen sulphide-lactose (DHL) agar, with and without antimicrobials (cefotaxime and ciprofloxacin), were quantified, and E. coli isolates were analysed for their susceptibility to antimicrobials and the presence of bla genes. DNA extracted from faecal samples was used to quantify bla genes using quantitative PCR (qPCR).ResultsThe isolation rates of cefotaxime- and ciprofloxacin-resistant E. coli were 6.9% and 12.4%, respectively, using agars without antimicrobials, and 12.0% and 24.4%, respectively, using agars with antimicrobials. For samples from which cefotaxime- and ciprofloxacin-resistant E. coli were isolated only using agars with antimicrobials, the ratios of cfu on DHL agars with and without antimicrobials were below −2 log. E. coli harbouring bla genes were isolated from 35.0% of the faecal samples using agars, and bla genes were detected in 65.0% of faecal DNA samples using qPCR.ConclusionsAmong people carrying cefotaxime- and ciprofloxacin-resistant E. coli in non-clinical settings, cefotaxime- and ciprofloxacin-resistant E. coli were not dominant in half of the subjects. These individuals may play a role as reservoirs of antimicrobial-resistant bacteria.

Temporal Trends in Antimicrobial Resistance of Fecal Escherichia coli from Deer

The changing epidemiologic role of wildlife as reservoirs of antimicrobial-resistant bacteria (ARB) is poorly understood. In this study, we characterize the phenotypic resistance of commensal Escherichia coli from fecal samples of 879 individual white-tailed (Odocoileus virginianus; WTD) over a ten-year period and analyze resistance patterns. Our results show commensal E. coli from WTD had significant linear increases in reduced susceptibility to 5 of 12 antimicrobials, including broad-spectrum cephalosporins and fluoroquinolones, from 2006 to 2016. In addition, the relative frequency distribution of minimal inhibitory concentrations of two additional antimicrobials shifted towards higher values from across the study period. The prevalence of multidrug-resistant commensal E. coli increased over the study period with a prevalence of 0%, 2.2%, and 3.7% in 2006, 2012, and 2016, respectively. WTD may be persistently and increasingly exposed to antibiotics or their residues, ARB, and/or antimicrobial resistance genes via contaminated environments like surface water receiving treated wastewater effluent.

Bacterial zoonoses transmitted by household pets and as reservoirs of antimicrobial resistant bacteria

Numerous individuals are committed to growing pet creatures like cats, dogs, and rats etc., pay care for them and as a result of this, there's a boost of their populace in advanced culture. The close interaction between family pets and individuals offers ideal conditions for bacterial transmission. Distinctive sorts of antimicrobial agents are exploited for animal husbandry and studies have revealed that many bacteria have attained confrontation against them viz., Staphylococcus intermedius, Escherichia coli, methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococci and multidrug-resistant Salmonella typhi etc. and a few of these are a prospective for zoonotic transmission. In the current review, the attention has been paid on how household pets, especially dogs disperse the antimicrobial resistance in contrast to that of food animals. A lot of evidences are accessible on food animals and nation-wide scrutiny programmes solely hub on food animals; therefore, for steerage antimicrobial use policy in small animal veterinary exercise as well as for gauging the chance of transmission of antimicrobial resistance to humans' statistics on pet animals are sincerely needed. Transmission of such organisms, especially pathogenic staphylococci, occurs between pets, owners, and veterinary staff, and pets can act as reservoirs of such bacteria; this may additionally have an impact on the use of antimicrobials in human medicine. There is a need to generate statistics concerning each the levels of carriage of such microorganism in pets and the risk factors associated with the switch of the microorganism to human beings who have contact with infected pets, as nicely as to improve hygiene measures in veterinary practice.

Faecal microbiota and antibiotic resistance genes in migratory waterbirds with contrasting habitat use

Migratory birds may have a vital role in the spread of antimicrobial resistance across habitats and regions, but empirical data remain scarce. We investigated differences in the gut microbiome composition and the abundance of antibiotic resistance genes (ARGs) in faeces from four migratory waterbirds wintering in South-West Spain that differ in their habitat use. The white stork Ciconia ciconia and lesser black-backed gull Larus fuscus are omnivorous and opportunistic birds that use highly anthropogenic habitats such as landfills and urban areas. The greylag goose Anser anser and common crane Grus grus are herbivores and use more natural habitats. Fresh faeces from 15 individuals of each species were analysed to assess the composition of bacterial communities using 16S rRNA amplicon-targeted sequencing, and to quantify the abundance of the Class I integron integrase gene (intI1) as well as genes encoding resistance to sulfonamides (sul1), beta-lactams (blaTEM, blaKPC and blaNDM), tetracyclines (tetW), fluoroquinolones (qnrS), and colistin (mcr-1) using qPCR. Bacterial communities in gull faeces were the richest and most diverse. Beta diversity analysis showed segregation in faecal communities between bird species, but those from storks and gulls were the most similar, these being the species that regularly feed in landfills. Potential bacterial pathogens identified in faeces differed significantly between bird species, with higher relative abundance in gulls. Faeces from birds that feed in landfills (stork and gull) contained a significantly higher abundance of ARGs (sul1, blaTEM, and tetW). Genes conferring resistance to last resort antibiotics such as carbapenems (blaKPC) and colistin (mcr-1) were only observed in faeces from gulls. These results show that these bird species are reservoirs of antimicrobial resistant bacteria and suggest that waterbirds may disseminate antibiotic resistance across environments (e.g., from landfills to ricefields or water supplies), and thus constitute a risk for their further spread to wildlife and humans.

More diversified antibiotic resistance genes in chickens and workers of the live poultry markets

BackgroundPoultry farms and LPMs are a reservoir of antimicrobial resistant bacteria and resistance genes from feces. The LPM is an important interface between humans, farm animals, and environments in a typical urban environment, and it is considered a reservoir for ARGs and viruses. However, the antibiotic resistomes shared between chicken farms and LPMs, and that of LPM workers and people who have no contact with the LPMs remains unknown. MethodsWe characterized the resistome and bacterial microbiome of farm chickens and LPMs and LPM workers and control subjects. The mobile ARGs identified in chickens and the distribution of the mcr-family genes in publicly bacterial genomes and chicken gut metagenomes was analyzed, respectively. In addition, the prevalence of mcr-1 in LPMs following the ban on colistin-positive additives in China was explored. ResultsBy profiling the microbiomes and resistomes in chicken farms, LPMs, LPM workers, and LPM environments, we found that the bacterial community composition and resistomes were significantly different between the farms and the LPMs, and the LPM samples possessed more diversified ARGs (59 types) than the farms. Some mobile ARGs, such as mcr-1 and tet(X3), identified in chicken farms, LPMs, LPM workers, and LPM environments were also harbored by human clinical pathogens. Moreover, we found that the resistomes were significantly different between the LPM workers and those who have no contact with the LPMs, and more diversified ARGs (188 types) were observed in the LPM workers. It is also worth noting that mcr-10 was identified in both human (5.2%, 96/1,859) and chicken (1.5%, 14/910) gut microbiomes. Although mcr-1 prevalence decreased significantly in the LPMs across the eight provinces in China, from 190/333 (57.1%) samples in September 2016-March 2017 to 208/544 (38.2%) samples in August 2018-May 2019, it is widespread and continuous in the LPMs. ConclusionLive poultry trade has a significant effect on the diversity of ARGs in LPM workers, chickens, and environments in China, driven by human selection with the live poultry trade. Our findings highlight the live poultry trade as ARG disseminators into LPMs, which serve as an interface of LPM environments even LPM workers, and that could urge Government to have better control of LPMs in China. Further studies on the factors that promote antibiotic resistance exchange between LPM environments, human commensals, and pathogens, are warranted.

Farm dust resistomes and bacterial microbiomes in European poultry and pig farms

BackgroundLivestock farms are a reservoir of antimicrobial resistant bacteria from feces. Airborne dust-bound bacteria can spread across the barn and to the outdoor environment. Therefore, exposure to farm dust may be of concern for animals, farmers and neighboring residents. Although dust is a potential route of transmission, little is known about the resistome and bacterial microbiome of farm dust. ObjectivesWe describe the resistome and bacterial microbiome of pig and poultry farm dust and their relation with animal feces resistomes and bacterial microbiomes, and on-farm antimicrobial usage (AMU). In addition, the relation between dust and farmers’ stool resistomes was explored. MethodsIn the EFFORT-study, resistomes and bacterial microbiomes of indoor farm dust collected on Electrostatic Dust fall Collectors (EDCs), and animal feces of 35 conventional broiler and 44 farrow-to-finish pig farms from nine European countries were determined by shotgun metagenomic analysis. The analysis also included 79 stool samples from farmers working or living at 12 broiler and 19 pig farms and 46 human controls. Relative abundance of and variation in resistome and bacterial composition of farm dust was described and compared to animal feces and farmers’ stool. ResultsThe farm dust resistome contained a large variety of antimicrobial resistance genes (ARGs); more than the animal fecal resistome. For both poultry and pigs, composition of dust resistomes finds (partly) its origin in animal feces as dust resistomes correlated significantly with fecal resistomes. The dust bacterial microbiome also correlated significantly with the dust resistome composition. A positive association between AMU in animals on the farm and the total abundance of the dust resistome was found. Occupational exposure to pig farm dust or animal feces may contribute to farmers’ resistomes, however no major shifts in farmers resistome towards feces or dust resistomes were found in this study. ConclusionPoultry and pig farm dust resistomes are rich and abundant and associated with the fecal resistome of the animals and the dust bacterial microbiome.

High-Throughput Detection and Characterization of Antimicrobial Resistant Enterococcus sp. Isolates from GI Tracts of European Starlings Visiting Concentrated Animal Feeding Operations.

Antimicrobial resistant enteric bacteria can easily contaminate the environment and other vehicles through the deposition of human and animal feces. In turn, humans can be exposed to these antimicrobial resistant (AMR) bacteria through contaminated food products and/or contaminated drinking water. As wildlife are firmly established as reservoirs of AMR bacteria and serve as potential vectors in the constant spread of AMR, limiting contact between wildlife and livestock and effective tracking of AMR bacteria can help minimize AMR dissemination to humans through contaminated food and water. Enterococcus spp., which are known opportunistic pathogens, constantly found in gastrointestinal tracts of mammalian and avian species, swiftly evolve and cultivate AMR genotypes and phenotypes, which they easily distribute to other bacteria, including several major bacterial pathogens. In this study, we evaluated the use of high throughput detection and characterization of enterococci from wildlife [European starlings (Sturnus vulgaris)] by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) following culture-based isolation. MALDI-TOF MS successfully identified 658 Enterococcus spp. isolates out of 718 presumptive isolates collected from gastrointestinal tracts of European starlings, which were captured near livestock operations in Colorado, Iowa, Kansas, Missouri, and Texas; antimicrobial susceptibility testing was then performed using 13 clinically significant antibiotics.

Inactivation of carbapenemase-producing Enterobacterales during anaerobic co-digestion of food waste and pig manure

Animal manures and food wastes are significant reservoirs of antimicrobial resistant bacteria, among which carbapenemase-producing Enterobacterales (CPE) are resistant to almost all antibiotics and have been detected in these wastes. This study investigated the inactivation of three different CPE strains (KPC-3, OXA-48 and NDM-1 carbapenemase-producing Klebsiella pneumoniae) during anaerobic co-digestion of food waste and pig manure at various total solids (TS) contents. The results showed that the elimination of CPE strains was more efficient at higher TS contents. While increasing the TS contents from 5% to 20%, the survival time of CPE decreased from 9 days to 2 days. Statistical analysis revealed significant negative correlations between total volatile fatty acids (VFAs) and the survival time of two CPE strains (KPC-3 and OXA-48 producing Klebsiella pneumoniae) (P < 0.05), indicating the possible elimination effects of VFAs on antibiotic resistant bacteria.

Novel Mobilizable Genomic Island GEI-D18A Mediates Conjugational Transfer of Antibiotic Resistance Genes in the Multidrug-Resistant Strain Rheinheimera sp. D18.

Aquatic environments act as reservoirs of antimicrobial-resistant bacteria and antimicrobial resistance (AMR) genes, and the dissemination of antibiotic resistance from these environments is of increasing concern. In this study, a multidrug-resistant bacterial strain, identified as Rheinheimera sp. D18, was isolated from the sea water of an industrial maricultural system in the Yellow Sea, China. Whole-genome sequencing of D18 revealed the presence of a novel 25.8 kb antibiotic resistance island, designated GEI-D18A, which carries several antibiotic resistance genes (ARGs), including aadA1, aacA3, tetR, tet(B), catA, dfrA37, and three sul1 genes. Besides, integrase, transposase, resolvase, and recombinase encoding genes were also identified in GEI-D18A. The transferability of GEI-D18A was confirmed by mating experiments between Rheinheimera sp. D18 and Escherichia coli 25DN, and efflux pump inhibitor assays also suggested that tet(B) in GEI-D18A was responsible for tetracycline resistance in both D18 and the transconjugant. This study represents the first characterization of a mobilizable antibiotic resistance island in a species of Rheinheimera and provides evidence that Rheinheimera spp. could be important reservoirs and vehicles for ARGs in the Yellow Sea area.

Slovak Sheep Cheese Bryndza as a Reservoir of Antimicrobial-Resistant Bacteria

Abstract The aim of this study was to determine antibiotic resistance of bacteria isolated from sheep cheese “bryndza”. The cheese samples were obtained from five Slovak farms and different groups of bacteria isolated from cheese samples. Enterobacteriaceae and Lactobacillaceae were the most distributed bacterial families with other bacterial families as Enterococcaceae, Staphylococcaceae and Moraxellaceae were identified. Enterobacteriaceae were tested to cefepime (cephalosporins) and imipenem (carbapenems), Lactobacillaceae family were tested for resistance to vancomycin (glycosides) and to imipenem. Staphylococcaceae were tested for resistance against tigecycline (tetracycline) and chloramphenicol (amphenicols). Enterococcaceae family was tested against tigecycline and imipenem. Genus Acinetobacter of the Moraxellaceae family was tested for resistance to ciprofloxacin (fluoroquinolones) and to imipenem. All tested bacteria showed susceptibility against the chosen antibiotics.

Wild boar as a reservoir of antimicrobial resistance.

Antimicrobial resistance (AMR) has been recognized as an emerging and growing problem worldwide. Knowledge concerning AMR bacteria circulating in wildlife is currently limited, although it could provide important insights into AMR emergence and persistence. Across Europe, wild boar (Sus scrofa) populations have dramatically increased their distribution and number over the last decades. In the context of AMR dynamics, wild boar is a perfect model species to unveil the emergence, spread and persistence of AMR at the human-livestock-wildlife interface. Here, we summarize the current knowledge on the importance of wild boar as a reservoir of antimicrobial resistant bacteria, and its possible use as sentinel species for surveillance. Analyses of available data showed a rising interest on this topic in the last years, highlighting the growing concern on wild boar potential role as AMR facilitator and it is foreseen that the importance of antimicrobial resistance research in wild boar will continue to increase in years to come. Available studieshave been focused on specific bacterial species, particularlyE. coli, Salmonellaspp. andEnterococcusspp., bioindicators of AMR, and have been mainly conducted in three countries: Spain, Portugal and Germany.Strikingly, AMR surveillance in wild boar is uneven and still poorly allocated as many wild boar high-density countries do not yet have publications on the topic.Overall, accumulated data showed thatwild boar are carriers of antimicrobial resistant bacteria, withvariation in the prevalence of bacterial species and thepercentage of resistance to different antibiotics. Thelack of harmonized sampling and testing protocols makes it difficult to compare AMR in wild boar.The need for the establishment of standardised protocols keen to provide quantitative comparable data is highlighted. We finally suggest the long-term monitoring of wild boar as a sentinel species for AMR surveillance in order to inform public policies on this topic.

Occurrence of extended-spectrum β-lactamase-producing bacteria in urban Clinton River habitat.

The aim of this study was to determine whether Clinton River water is contaminated with antibiotics and is a reservoir of antimicrobial-resistant bacteria. Water samples were taken from two sites of Clinton River. Antimicrobial-resistant bacteria were enumerated on agar plates supplemented with six commonly used antibiotics. Extended-spectrum β-lactamase (ESBL)-producing bacteria were identified using a BD Phoenix™ System and by 16S rRNA gene sequencing. Antimicrobial resistance gene transfer was performed by conjugation studies and the location of genes was determined by Southern hybridisation. Virulence properties of ESBL-producing isolates were determined by assessing their biofilm-forming ability, cellular toxicity, and induction of an inflammatory response in intestinal epithelial (Caco-2) cells. 16S rRNA analysis of water samples showed the presence of potentially pathogenic bacteria (e.g. Shigella flexneri, Klebsiella pneumoniae, Aeromonas punctata and Pseudomonas aeruginosa). Among 64 biochemically identified bacterial isolates tested, 42% were resistant to cefotaxime, 34% to chloramphenicol, 9% to tetracycline, 11% to ciprofloxacin and 9% to gentamicin. Of 27 cefotaxime-resistant isolates, 11 (41%) were ESBL-positive and possessed either blaCTX-M (n=9), blaTEM (n=1) or blaKPC (n=1). Comparative analysis of ESBL gene sequences from Clinton River water bacteria showed 98-100% identity with clinical isolates. ESBL-producing isolates from Clinton River water were found to form biofilms, induced inflammatory cytokines and caused toxicity to epithelial cells. Clinton River water contains isolates with ESBL genes identical to clinical isolates and possessing virulence properties, thus it could be a potential reservoir in causing human infections.

Role of Flies in the Maintenance of Antimicrobial Resistance in Farm Environments.

Flies play an important role as vectors in the transmission of antimicrobial-resistant bacteria (ARB) and are hypothesized to transfer ARB between internal and external livestock housing areas. The aim of this study was to understand the role that flies may play in the maintenance of ARB in the farm environment. We first evaluated the fate of ingested antimicrobial-resistant Escherichia coli harboring a plasmid containing antimicrobial-resistance genes (ARGs) throughout the housefly (Musca domestica) life cycle, from adult to the subsequent F1 generation. Antimicrobial-resistant E. coli was isolated from different life cycle stages and ARG carriage quantified. The ingested E. coli persisted throughout the fly life cycle, and ARG carriage was maintained at a constant level in the housefly microbiota. To clarify the transmission of ARB from flies to livestock, 30-day-old chickens were inoculated with maggots containing antimicrobial-resistant E. coli. Based on the quantification of bacteria isolated from cecal samples, antimicrobial-resistant E. coli persisted in these chickens for at least 16 days. These results suggest that flies act as a reservoir of ARB throughout their life cycle and may therefore be involved in the maintenance and circulation of ARB in the farm environment.

First report on extended-spectrum beta-lactamase (ESBL) producing Escherichia coli from European free-tailed bats (Tadarida teniotis) in Portugal: A one-health approach of a hidden contamination problem.

The main aim of this study was to characterize the diversity of extended-spectrum beta-lactamases (ESBLs) in Escherichia coli isolates from European free tailed-bats (Tadarida teniotis) in Portugal. ESBL-producing E. coli isolates were recovered from 14 of 146 faecal samples (9.6%) and a total of 19 isolates were completely characterized. The more prevalent beta-lactamase genes detected were blaCTX-M-1 (57.9%) and blaCTX-M-3 (36.8%), followed by blaSHV (31.6%), blaTEM (21.1%), blaOXA (10.5%) and blaCTX-M-9 (10.5%). Among other associated resistance genes studied, tet(A) and tet(B) were predominant and fimA was the main virulence factor detected. Phylogroups D (47.4%) and A (31.6%) were the more prevalent, followed by group B2 (21.1%). Bats are reservoirs of antimicrobial-resistant bacteria and resistance determinants and is important in further studies to identify the main sources of pollution in the environment, such as water or insects that may contain these multiresistant organisms.

Otter fecal enterococci as general indicators of antimicrobial resistance dissemination in aquatic environments

Antimicrobial resistance is an emerging worldwide concern, as the use of antibiotics is crucial for human and animal health protection. Evaluations of the antimicrobial susceptibility of enteric microbiota can be used as an indicator of resistance dispersion in the environment. Commensal intestinal bacteria, such as Enterococcus spp., often act as reservoirs for antimicrobial resistance determinants and may allow gene transfer to animal or human pathogens present in the same habitats, including contaminated water. As contact between wild animals and human and domestic animal populations is increasing, the potential for dissemination of resistant pathogens to wildlife can be considered an emerging problem.This study aimed to confirm the potential of the intestinal commensal bacteria of otters as a model for assessing antimicrobial resistance dissemination in the environment. We evaluated the presence of antimicrobial-resistant enterococci in spraints from Eurasian and Neotropical otters, collected in Portugal and Brazil during 2015 and 2016 in different climatic seasons. We isolated Enterococcus spp., and then determined their clonal diversity and antimicrobial resistance profiles.The bacterial collection studied revealed high genomic diversity, ensuring its representativeness regarding the diversity of enterococci eliminated to the environment via otter spraints. Only one isolate, collected in Portugal, was susceptible to all the antimicrobial compounds tested, and the majority showed resistance to more than one antibiotic. We found high resistance levels to clindamycin in isolates from spraints collected in both countries, representing a particular concern for human health, as lincosamides are frequently used in cases of therapeutic failure. Antimicrobial resistance was higher in enterococci obtained from otter spraints collected in Brazil. However, significant correlations between antimicrobial resistance to individual compounds and country were only observed for Enrofloxacin and Vancomycin, which may be due to enrofloxacin use in animal production near the sample areas, particularly in poultry and cattle farms.Our results confirm the potential for these microorganisms to be used as indicators for monitoring antimicrobial resistance dissemination. These findings suggest that aquatic habitats occupied by otters may act as reservoirs of antimicrobial-resistant bacteria, the presence of which could impact human health through exposure to contaminated waters during fishing or recreational activities. Appropriate management and monitoring plans must be established to protect the environment and public health against the adverse effects of antibiotics, with this being particularly important in countries where antibiotics are increasingly being administered in veterinary settings.