Methicillin-resistant and methicillin-susceptible Staphylococcus aureus in French hedgehogs admitted to a wildlife health center

The <i>mecC</i> gene conferring methicillin-resistance has always been found on a SCC<i>mec</i> type XI element and is largely restricted to the few clonal complexes CC130, CC1943, CC425, CC49 and CC599. The occurrence of the <i>mecC</i> gene in many different hosts highlighted its One Health importance, even though European hedgehogs (<i>Erinaceus europaeus</i>) are considered its natural reservoir, most probably because of the selective pressure imposed by beta-lactam-producing dermatophytes (<i>Trichophyton erinacei</i>) that colonize the skin of these mammals. Surprisingly, while the presence of <i>T. erinacei</i> on the French territory has been proven, no <i>mecC</i>-positive methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) isolate has been reported yet from hedgehogs. We thus sampled 139 hedgehogs brought to a wildlife center; 128 were <i>S. aureus</i> carriers and 25 (18.0 %) presented a MRSA isolate, of which 21 (15.1 %) displayed the <i>mecC</i> gene. All 161 <i>S. aureus</i> collected were whole-genome sequenced. The <i>mecC</i>-MRSA belonged to the classical CCs, i.e. CC130, CC1943 and CC49. The majority (98/139, 70.5 %) of the methicillin-susceptible <i>Staphylococcus aureus</i> (MSSA) isolates also belonged to these three CCs. A phylogenetic comparison with <i>mecC</i>-MRSA isolates from all over Europe and New-Zealand showed local adaptations, despite the fact that they all belonged to the same CCs. The acquisition of the SCC<i>mec</i> type XI element by a concomitant MSSA could not be observed in the same animal, but such a transfer might be suggested since identical clones were identified, one MSSA and one MRSA, though in different animals. In parallel, we conducted a detailed analysis of the SCC<i>mec</i> type XI element as well as specific virulence factors (a <i>tst</i> variant and the <i>vwb</i> _SaPI gene). Results led us to hypothesize that the <i>mecC</i> gene might be acquired through selective pressure of <i>T. erinacei</i> on MSSA, some of which were acquired a long time ago from ruminants and are now colonizing the skin of the hedgehogs.