Antimicrobial Resistance In Enterobacteriales Isolates From Wild Foxes (Vulpes Vulpes)

Antimicrobial resistance (AMR) is recognized as a global public health threat. Resistant bacteria have been disseminated in ecosystems with AMR in isolates from wildlife which were not directly exposed to antimicrobials has been reported. The aim of the present study was to detect AMR in Enterobacteriales isolates recovered from wild red foxes (Vulpes vulpes) in Latvia. Identified microorganisms were confirmed with matrix-assisted laser desorption/ionization (MALDI-TOF MS), and antimicrobial resistance was detected with the minimum inhibitory concentration (MIC) test. Antimicrobial resistance genes were identified with whole-genome sequencing (WGS). A total of 27 isolates of Enterobacteriales, including Enterobacter cloacea (1), E. asburiae (1), Enterobacter coli (21), Hafnia alvei (3) and Salmonella Typhimurium (1), were identified in 32 red fox faecal samples. Among the isolates, 19 (70%) did not exhibit resistance to any of the tested antimicrobials. None of the strains exhibited multidrug resistance. Resistances to ampicillin (4/27, 15%), colistin (3/27, 11%), azithromycin (2/27, 7%), ceftazidime (2/27, 7%) and cefotaxime (2/27, 7%) were the most frequently reported; the antimicrobial resistance pattern differed between Enterobacteriales species. S. Typhimurium was susceptible against all antibiotics tested. The most prevalent AMR genes were acrF, blaEC and mdtM. One E. coli (1/21, 5%) isolate was confirmed as extended-spectrum beta-lactamase producing E. coli (blaTEM-1). The present study highlights the presence of AMR in Enterobacteriales in foxes from areas without direct exposure to anthropogenic factors.