Detection of methicillin-resistant Staphylococcus aureus sequence type 8 in pigs, production environment, and human beings.

Two follow-up studies of a positive methicillin-resistant Staphylococcus aureus (MRSA) finding in the 2008 European Union baseline survey on MRSA in pig herds were performed to gain more knowledge about the epidemiology of the particular MRSA type, a known human type (ST8/t008), among pigs. Two persons on a Norwegian farm in the study were found to be MRSA carriers, and human-to-animal transmission was suspected. In the first follow-up study, all pigs (n  =  346) were sampled by taking nasal swabs. A pooled sample from 5 individual pigs housed together in a single pen, and a dust sample from the equipment in the same room, were positive. Dust samples from a building housing MRSA-negative animals were negative. The MRSA was not detected in the second follow-up, after removing positive animals from the farm and cleaning and disinfecting. A low MRSA occurrence among the animals was found, suggesting that MRSA ST8/t008 may be less able to colonize and persist in pig holdings compared with more host-adapted S. aureus strains.