Epidemiological and molecular evidence of a monophyletic infection with Staphylococcus aureus causing a purulent dermatitis in a dairy farmer and multiple cases of mastitis in his cows.

An epidemiological and molecular investigation of a cutaneous suppurative infection with Staphylococcus aureus in a dairy farmer, occurring concurrently with an outbreak of clinical mastitis in his herd, was carried out. A common aetiology for the diseases in the farmer and his cows was established by combining clinical evidence with a molecular genomic analysis of the bacterial isolates using pulsed field gel electrophoresis of DNA macro-restriction fragments. This case indicates the possibility of the emergence and circulation of anthropozoonotic clones of S. aureus in dairy herds. It also provides further evidence of the severe impact of infection with highly virulent clones on dairy lactating cattle.