# Antimicrobial Resistance and Wildlife: Occurrence of Antimicrobial Resistance Genes in Red Foxes (Vulpes vulpes, Linnaeus, 1758), in Italy

## TL;DR

This study shows that red foxes in Italy carry antimicrobial resistance genes, suggesting they can act as indicators of environmental contamination.

## Contribution

The study demonstrates that red foxes can serve as sentinels for antimicrobial resistance in the environment using a culture-independent molecular method.

## Key findings

- 61% of red fox samples tested positive for one or more antimicrobial resistance genes.
- 13 specific resistance genes were detected in the foxes, including tet and sul family genes.
- Red foxes may act as indicators of antimicrobial-resistant bacteria in contaminated environments.

## Abstract

Antimicrobial resistance is a widespread problem, occurring in clinical, veterinary, agricultural, and environmental settings, strongly influenced by human activities like the overuse and misuse of antimicrobials. In this study, an epidemiological investigation of the spread of antimicrobial resistance genes was performed by testing splenic samples of 127 red foxes via a molecular approach. Positivity for one or more resistance genes was found in 78 (61%) of the samples tested. These results confirm that foxes, which feed on human waste, scavenge contaminated carcasses, and consume peri-domestic prey, could be sentinels of the presence of antimicrobial resistant bacteria in contaminated environments.

Clinically significant antimicrobial-resistant bacteria and resistance genes are increasingly being reported in wildlife. In this study, 127 splenic samples from red foxes (Vulpes vulpes) from northern and central Italy were analysed for the presence of resistance genes against antimicrobials such as tetracycline, sulphonamide, β-lactam, and colistin, which were previously extensively used in human and veterinary management of bacterial diseases. One or more antimicrobial resistance genes were detected in 78 (61%) of 127 splenic samples. Polymerase chain reaction positivity was revealed for 13 genes—tet(A), tet(B), tet(K), tet(L), tet(M), tet(O), tetA(P), tet(Q), tet(S), tet(X), sul1, sul2, and blaTEM-1—out of the 21 tested genes. Our results, corroborated by reports in the literature, confirm the potential role of the red fox as a sentinel for antimicrobial-resistant bacteria in contaminated environments and suggest that detecting resistance genes in biological samples by a culture-independent method might be an effective tool for the epidemiological study of antimicrobial resistance in wildlife.