Foxes as a potential wildlife reservoir for mecA-positive Staphylococci

Methicillin-resistant staphylococci (MRS), and methicillin-resistant Staphylococcus aureus (MRSA) in particular, have become a public and veterinary health concern. The search for MRS reservoirs outside human hospitals is needed in order to understand the reasons for their persistence and to control their spread. MRS have been isolated from rats, but little is known about their occurrence in foxes. In view of the perceived increasing proximity between people and foxes in the U.K. and the well-documented potential of foxes as hosts for zoonotic pathogens, this study examined whether foxes can be a reservoir for MRS. This study examined the carriage of staphylococci and their antimicrobial resistance patterns in 38 foxes (Vulpes vulpes) from rural and semirural areas in the U.K. Staphylococci were isolated by enrichment culture from nasal, oral, axillary, and perineal swabs and speciated by standard bacteriological tests and API ID32 STAPH (bioMérieux, Marcy l'Etoile, France). Antimicrobial resistance was investigated by disc diffusion tests and identification of mecA. Thirty-seven staphylococcal isolates were identified from 35 of the 38 foxes. All isolates were coagulase-negative and most frequently included species from the S. sciuri group (35%), S. equorum (27%), and S. capitis (22%). All were phenotypically resistant to methicillin, and mecA was detected in 33 (89%) of isolates, but only 10 (27%) showed broad β-lactam antibiotic resistance. Methicillin-resistant S. aureus was not identified. These results indicate that foxes are a potential wildlife reservoir for mecA-positive staphylococci. Selection pressure from environmental contamination with antimicrobials should be considered.