Findings of Methicillin-Resistant Strains of Staphylococcus aureus in Livestock

The aim of our study was to determine the occurrence of methicillin resistant Staphylococcus aureus (MRSA) at dairy farms in the Czech Republic. Altogether 1061 samples from 95 farms were examined. The samples analysed were milk (individual and bulk tank milk samples), animal swabs and swabs from the farm environment. In total, 299 S. aureus isolates were obtained, of which 23 were MRSA. These MRSA isolates originated from three farms (13 isolates from farm A and 5 isolates from each of farms B and C). All MRSA isolates carried the mecA gene while none of them carried the genes for PVL, TSST-I and exfoliatins. Only the isolates from goat farm C were positive for the genes encoding enterotoxins. By SCCmec typing, the strains were classified as community-associated MRSA carrying SCCmec IV or V. This study revealed that animals can be an important source of methicillin resistant staphylococci and represent a potential hazard of further spread.