Results of a study recently published in the journal Clinical Infectious Diseases are likely to drive increased discussion of antibiotic use in livestock and emergence of antibiotic-resistant pathogens. The researchers, from the University of Iowa, Kent State University and the National Cancer Institute, Rockville, Maryland, tested and monitored 1,242 Iowa residents for Staphylococcus aureus colonization or infection over a 17-month period. The study group included individuals with regular exposure to swine and urban residents for comparison.

The researchers tested for S. aureus, methicillin-resistant S. aureus (MRSA), tetracycline-resistant S. aureus (TRSA), multidrug-resistant S. aureus (MDRSA), and livestock-associated S. aureus ( LA-SA).

Of the participants, 351, or 26 percent, carried S. aureus. Thirty-four, or 2.5 percent of participants tested positive for MRSA, while the tests isolated LA-SA from 131 or 9.8 of the participants.

Individuals with current swine exposure were significantly more likely to carry S. aureus, with a prevalence ratio of  1.8, TRSA with a prevalence ratio of 8.4, MDRSA with a prevalence ratio of 6.1, and LA-SA with a prevalence ratio of 5.8. They did not find a significant difference in MRSA colonization between the swine-exposed and non-swine-exposed groups.

The researchers concluded that swine workers are six times more likely to carry MDRSA than those without swine exposure.

In an article from Reuters, the National Pork Producers Council pointed out that other studies have shown hog farming does not create an increased risk for staph infections.

An abstract of the research report is available online from Clinical Infectious Diseases, and the full report can be purchased on the same site.