Spread of Methicillin-ResistantStaphylococcus aureus(MRSA) Among Household Contacts of Individuals With Nosocomially Acquired MRSA

Abstract

Objective: To determine the frequency with which methicillin-resistantStaphylococcus aureus(MRSA) is spread from colonized or infected patients to their household and community contacts.Design: Retrospective cohort study.Setting: University hospital.Participants: Household and community contacts of MRSA-colonized or -infected patients for whom MRSA screening cultures were performed.Results: MRSA was isolated from 25 (14.5%) of 172 individuals. Among the contacts of index patients who had at least one MRSA-colonized contact, those with close contact to the index patient were 7.5 times more likely to be colonized (53% vs 7%; 95% confidence interval, 1.1 to 50.3;P= .002). An analysis of antimicrobial susceptibility and DNA fingerprint patterns suggested person-to-person spread.Conclusions: MRSA colonization occurs frequently among household and community contacts of patients with nosocomially acquired MRSA, suggesting that transmission of nosocomially acquired MRSA outside of the healthcare setting may be a substantial source of MRSA colonization and infection in the community.