Abstract
Increase of antimicrobial resistance (AMR) is a global threat to health. The AMR profile of bacteria isolated from domesticated animals and free-ranging wildlife has been studied, but there are relatively few studies of bacteria isolated from captive wild animals. Understanding the dynamics of AMR in different populations is key to minimizing emergence of resistance and to preserve the efficacy of antimicrobials. In this study, fecal samples were collected from 17 species of healthy ungulates from a zoological collection in southeast England, which yielded 39
and 55
spp. isolates for further analysis. Antibiotic sensitivity was investigated using agar disk diffusion.
isolates were resistant to a range of antibiotics, with resistance to ampicillin being the most common (28%). All
isolates were susceptible to apramycin, enrofloxacin, chloramphenicol, and florfenicol. None tested positive for extended-spectrum beta-lactamase or AmpC activity. Seven of 39 (18%)
isolates were resistant to three or more antibiotic classes. The
isolates were further analyzed using multilocus sequence typing, which identified four pairs of identical sequence type isolates and 27 diverse strains. The
spp. isolates were resistant to a range of antibiotics, with resistance to cefpodoxime seen in 95% of isolates. All
spp. isolates were susceptible to ampicillin, gentamicin, chloramphenicol, and vancomycin. This study identified multidrug-resistant phenotypes in enterobacterial isolates that were like those commonly found in domestic ungulates. There was no apparent spatial clustering of the resistance profiles within the zoo. Review of the medical records of individual animals showed no direct relation to the AMR profiles observed. Observed resistance to antibiotics rarely or never used may have been due to coselection or directly acquired from other sources.