Methicillin-resistant Staphylococcus aureus containing mecC in Swedish dairy cows

BACKGROUND Hitherto, methicillin-resistant Staphylococcus aureus (MRSA) has not been detected in Swedish cattle. However, due to the report of mecC, a novel homologue to the mecA gene, there was reason to re-evaluate susceptibility results from strain collections of Staphylococcus aureus and test suspected isolates for the presence of mecC. FINDINGS Bovine isolates of S. aureus with elevated minimum inhibitory concentrations of beta-lactams were retrospectively tested for presence of mecC. In four of the isolates mecC was detected. CONCLUSION In Sweden, this is the first finding of MRSA in cattle and the first detection of MRSA harbouring mecC of domestic animal origin. MRSA in animal populations has implications as a potential reservoir with risk for spread to humans. Occurrence of MRSA among Swedish cattle appears still very limited.