Invasive methicillin-resistant Staphylococcus aureus infections in the United States.

Data was taken from population-based surveillance for invasive MRSA in 9 sites across the US during 2004 and 2005. Reports of MRSA were classified as either healthcare-associated (either hospital-onset or community-onset) or community-associated (patients without established health care risk factors for MRSA). There were 8987 observed cases of invasive MRSA reported. Most infections were healthcare-associated: 5250 (58.4%) were community-onset infections, 2389 (26.6%) were hospital-onset infections; 1234 (13.7%) were community-associated infections, and 114 (1.3%) could not be classified. In 2005, the standardized incidence rate of invasive MRSA was 31.8 per 100 000 (interval estimate, 24.4-35.2). Incidence rates were highest among persons 65 years and older, blacks and males. There were 1598 in-hospital deaths among patients with MRSA infection. JAMA2007;298(15):1763-71.