A Population‐Based Study of the Incidence and Molecular Epidemiology of Methicillin‐Resistant<i>Staphylococcus aureus</i>Disease in San Francisco, 2004–2005

The annual incidence of community-onset MRSA disease in San Francisco is substantial, surpassing that of hospital-onset disease. USA300 is the predominant clone in both the community and hospitals. The dissemination of USA300 from the community into the hospital setting has blurred its distinction as a community-associated pathogen.