A survey of the antimicrobial susceptibility of Escherichia coli isolated from Sable Island horses.
The feral horses of Sable Island are a geographically isolated population located ∼160 km off the east coast of Nova Scotia, Canada. Because these horses have no contact with domestic animals, have minimal contact with people, and have never received antimicrobials, they offer a unique opportunity to study the dissemination of antimicrobial resistance in unmanaged populations. As part of an ongoing multidisciplinary and individual-based monitoring program, we collected feces from 508 geolocalized horses (92% of the total population) between July and September 2014. We selectively cultured Escherichia coli on MacConkey and CHROMagar ESBL media. Antimicrobial susceptibilities were determined, and organisms resistant to β-lactam antimicrobials were screened for β-lactamase genes by PCR. Escherichia coli was recovered from 146 (28.7%) individuals, and the majority of isolates (97%) were susceptible to all drugs tested. Resistance to tetracycline was most common, including organisms isolated from 4 (2.7%) of the colonized horses. A single isolate resistant to ampicillin, ceftriaxone, and ceftiofur was identified, which possessed the CTX-M-1 gene. Our findings demonstrate that although antimicrobial resistance is not common in this remote population, clinically relevant resistance genes are present.
a Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
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Timonin
b Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada.|c College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn, TR10 9FE, UK.
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Poissant
b Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada.
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McLoughlin
a Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
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Hedlin
a Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
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Rubin
D000818:Animals; D000835:Animals, Wild / Q000382:microbiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002170:Canada; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D005243:Feces / Q000382:microbiology; D006736:Horses / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D009674:Nova Scotia; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases
BLSE; ESBL; Escherichia coli; Sable Island horses; animaux sauvages; antimicrobial resistance; chevaux de Sable Island; résistance aux antimicrobiens; wildlife