Livestock-associated Methicillin-ResistantStaphylococcus aureusin Humans, the Netherlands

To determine whether persons living in areas of high animal density are at increased risk for carrying livestockassociated methicillin-resistant Staphylococcus aureus (LA-MRSA), we used an existing dataset of persons in the Netherlands with LA-MRSA carriage and controls who carried other types of MRSA.Results of running univariate and multivariate logistic regression models indicated that living in livestock-dense areas increases the odds of nasal carriage of LA-MRSA.We found that doubling pig, cattle, and veal calf densities per municipality increased the odds of LA-MRSA carriage over carriage of other types of MRSA by 24.7% (95% CI 0.9%-54.2%),76.9% (95% CI 11.3%-81.3%),and 24.1% (95% CI 5.5%-45.9%),respectively, after adjusting for direct animal contact, living in a rural area, and the probable source of MRSA carriage.Controlling the spread of LA-MRSA thus requires giving attention to community members in animal-dense regions who are unaffi liated with livestock farming.S taphylococcus aureus is a zoonotic and human patho- gen that can cause a range of health outcomes in humans from minor to life-threatening infections of the skin, bloodstream, respiratory system, urinary tract, and surgical sites ( 1).An increasing proportion of S. aureus infections involve drug-resistant strains, including methicillin-resistant S. aureus (MRSA) (2).In 2007, 171,200 MRSA infec- Livestock Density as Risk Factor for Livestock-associated Methicillin-Resistant Staphylococcus aureus, the Netherlands