Community-associated methicillin-resistant Staphylococcus aureus skin and soft tissue infections at a public hospital: do public housing and incarceration amplify transmission?

To determine characteristics associated with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), 518 community-onset cases between 2001 and 2004 were compared with 704 controls who had community-associated Staphylococcus aureus which responds to methicillin-like antibiotics. The incidence of CA-MRSA skin and soft tissue infections increased from 24 cases per 100,000 people in 2000 to 164.2 cases per 100,000 people in 2005. The number of infections susceptible to antibiotics remained stable over this time, indicating that MRSA occurred in addition to and not in place of methicillin-susceptible Staphylococcus aureus (MSSA). For MRSA the risk factors were incarceration, African-American race/ethnicity and residence at a group of geographically proximate public housing complexes; older age was inversely related. Archives of Internal Medicine 2007;167:1026-33.