Population-based incidence and characteristics of community-onset Staphylococcus aureus infections with bacteremia in 4 metropolitan Connecticut areas, 1998

This study retrospectively analyzed the magnitude and epidemiology of commu nity-onset Staphylococcus aureus (COSA) infections and methicillin-resistan t S. aureus (MRSA) infections in 4 Connecticut metropolitan areas (populati on, 1.1 million). The study looked at hospital medical records of persons a dmitted with S. aureus bacteremia in 1998. COSA was categorized as "health care associated," "with underlying medical condition," or "no underlying me dical condition." Overall, 48% of S. aureus bacteremic infections were COSA (incidence, 17 cases/100,000 persons). Incidence increased with age and hi gher population density. In all, 62% of infections were health care associa ted; 85% of the remaining cases had underlying medical conditions. MRSA acc ounted for 16% of health care-associated cases and cases with underlying co nditions but no cases with no underlying conditions. COSA bacteremic infect ions are as common as those due to pneumococci. MRSA is a well-established cause of COSA among persons at high medical risk for S. aureus infection. A dditional study to understand community-onset MRSA acquisition is needed.