I think I was a little too optimistic about MRSA (methicillin resistant Staphylococcus aureus) in pigs staying in pigs and not spreading to humans. A recent study in the Netherlands found that people exposed to pigs were 1000 times (yes, one thousand) more likely to be MRSA carriers than the general population, and the MRSA strain was usually the ‘pig’ strain.
What does this mean? The authors conclude:
After introduction of the new MRSA risk category in a hospital [Mad Biologist: screening those in contact with farm animals], which is located in a region with a relatively high density of pig farms, the number of MRSA carriers immediately increased >300%. This challenges the Search and Destroy strategy. Part of this strategy is the screening of patients at risk of MRSA and isolating them until they are proven to be free of MRSA. If MRSA is present, isolation is continued until hospital discharge. The unexpected and sudden increase of the MRSA incidence in our hospital resulted in a shortage of isolation facilities. An additional problem is the treatment of carriers, which is also part of the Search and Destroy strategy. Pig and cattle farmers colonized with MRSA return to the source of MRSA after hospital discharge; this raises questions about treatment of carriers. Our findings indicate that, currently, this strain does not spread easily among humans, but more research on this aspect is needed. Although the increase in absolute numbers of MRSA carriers is obvious, the true impact for hospitals will depend on the virulence and transmissibility of this new clone.
This is not good.
Cited article: van Rijen MM, Van Keulen PH, Kluytmans JA. 2008. Increase in a Dutch hospital of methicillin-resistant Staphylococcus aureus related to animal farming. Clin Infect Dis. 2008 Jan 15;46(2):261-3.