Antimicrobial resistance genes in Andean foxes inhabiting anthropized landscapes in central Chile

Antimicrobial resistance (AMR) is considered an emerging public health problem. Greater AMR development rate is associated with "antibiotic-using" environments. Wildlife thriving in anthropized landscapes could be good indicators of the burden of AMR and antibiotic resistance genes (ARGs) in these areas. The aim of this study was to determine the presence and load of ARGs in fecal swabs of wild Andean foxes (Lycalopex culpaeus) from anthropized landscapes of central Chile. DNA was extracted from samples of 72 foxes; 22 ARGs encoding resistance against 8 antibiotic groups were evaluated using qPCR. Eighteen of the 22 ARGs were found and tet(Q) (65.3%; 15/72 of the samples) was the most common gene detected. Almost half of the foxes presented a 'multiresistant microbiome' (i.e. at least three ARG encoding resistance to different groups of antimicrobials). Prevalence of tet(Q) was higher in the cold-humid season than in the warm-dry season, but not for other genes. Up to 15 and 13 ARGs were detected in the fecal samples from two additional foxes that were kept 6 and 11 days, respectively, in a clinical environment (Wildlife Rescue Center) and received antibiotic treatment. Some of the ARGs detected (e.g. mecA and bla_CTX-M) in the present study are of particular concern from the public health perspective. Wild foxes seem to be good sentinels for ARG environmental burden in highly anthropized environments of central Chile.