Outbreak of skin infections sheds light on risk factors for bacterial resistance.

2004 MAY 14 - (NewsRx.com & NewsRx.net) -- Scientists identify two major risk factors for community-acquired skin infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in a report: previous antibiotic use and a genetic predisposition.

S. aureus is a common bacterium found on human nasal mucous membranes and skin, and strains that are resistant to methicillin can cause disease. Until recently drug-resistant strains were considered to be acquired almost exclusively in hospital settings, but reports of MRSA acquired in the community are increasing, and are most often associated with skin and soft-tissue infections such as furunculosis and cellulitis. Risk factors for infection by community-onset MRSA have to date been poorly understood by public health officials and other scientists.

To address this issue, Dr. Thomas W. Hennessy and colleagues of the U.S. Centers for Disease Control and Prevention and other institutions investigated a 1999 outbreak of furunculosis in rural southwestern Alaska. Their findings were published in the May 1, 2004, issue of the Journal of Infectious Diseases.

The researchers conducted a case-control study in one village located in the region of the outbreak. They identified 34 people with a laboratory-confirmed skin infection caused by community-onset MRSA, and 94 people with no history of skin infection in the previous year who were the study "controls." Infected persons and controls were similar in age and sex. Hennessy and colleagues found that people with MRSA skin infections had received significantly more courses of antibiotics in the year before the outbreak than had the controls (a median of four vs. two courses, p=0.01).

The researchers ...