MRSA found in Midwestern swine, workers

IOWA CITY, Iowa, Jan. 26 (UPI) -- U.S. researchers found a strain of methicillin-resistant Staphylococcus aureus, known as ST398, in a swine production system in the Midwest.

"Our results show that colonization of swine by MRSA was very common in one of two corporate swine production systems we studied," lead author Tara Smith of the University of Iowa College of Public Health said in a statement. "Because ST398 was found in both animals and humans, it suggests transmission between the two."

The findings, published in the journal PLoS One, said that the findings also suggest that once MRSA is introduced, it may spread broadly among both swine and their caretakers.

Agricultural animals could become an important reservoir for this bacterium, Smith said.

Staphylococcus aureus are bacteria commonly carried on the skin or in the nose of healthy people. MRSA is a type of staph that is resistant to the broad-spectrum antibiotics.

Investigators analyzed nasal swabs of 299 swine and 20 swine workers from two different production systems in Iowa and Illinois. At Production System A, the overall prevalence of MRSA was 70 percent in swine and 64 percent in workers. At Production System B, all swine and human samples were negative for MRSA.

The researchers could not determine why System A had a high prevalence rate of MRSA among its swine and swine handlers, but listed several differences compared to System B.