Presence of CDC risk factors for HA-MRSA* among patients with MSSA and MRSA infections.

*Absence of these risk factors comprise the CDC case definition for community-associated MRSA infections. Denominators for HA-MRSA risk factors exclude those interviewed patients who answered that that they did not know information requested of them and those patients about whom risk factor information could not be determined from chart review. For all 659 patients it was determined whether MRSA had been isolated from them at UCH since 1994, but for 295 patients, it could not be determined if MRSA had been isolated from them at another health care facility. The information regarding a stay in a long-term care facility was determined only for those patients lacking another health-care risk factor.Abbreviations: HA-, health care associated; MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-susceptible Staphylococcus aureus.