Transmission Dynamics of mecC Resistance Among Staphylococcal Species from Hedgehogs and Ticks

The European hedgehog has been proposed as a reservoir for mecC positive methicillin resistant Staphylococci, although the mechanism of how this methicillin resistance determinant spilled over into other wildlife, livestock and humans is not fully understood. Ticks are well known vectors of tick-borne diseases and parasitise livestock and wild animals, including hedgehogs. Furthermore, within their diverse microbiome they also harbour including Staphylococcaceae. This research aimed to characterise the presence of mecC Staphylococci and Mammaliicocci in ticks removed from hedgehogs and compare these with samples directly from hedgehogs to determine associations between the two. Presumptive Staphylococci were isolated from homogenised tick samples, hedgehog faecal samples and hedgehog skin samples. These isolates were screened for methicillin resistance and resistant isolates were subject to PCR analysis for the presence of mecA and mecC genes. Isolates were then identified using biochemical analysis. In total, 203 ticks from 21 hedgehogs, 254 field collected questing ticks, 17 faecal samples and six skin samples were collected and screened. A total of 54 isolates were obtained and 18 of these were identified to species level which were predominantly obtained from ticks. The most abundantly identified species was Staphylococcus xylosus (n=7), followed by Mammaliicoccus sciuri (n=3) and Mammaliicoccus lentus (n=3). A single mecC positive isolate was obtained from a tick sample; a 718bp mecC amplicon shared 100% sequence identity with the reference strain of mecC-MRSA (Staphylococcus aureus M10/0061). The Staphylococcaceae identified are frequently present in the environment and on the skin of mammals, but often overlooked as a potential reservoir of resistance genes. Similarly, Staphylococcaceae in ticks are not considered as significant. The finding of mecC in ticks but not hedgehogs suggests a potential role for ticks in the transmission of mecC that necessitates further research and consideration of ticks as a reservoir for antimicrobial resistance.