Nosocomial acquisition of methicillin-resistant Staphylococcus aureus during an outbreak of severe acute respiratory syndrome.

Poutanen, Susan M; Vearncombe, Mary; McGeer, Allison J; Gardam, Michael; Large, Grant; Simor, Andrew E

OBJECTIVE The four hospitals assessed in this study use active surveillance cultures for methicillin-resistant Staphylococcus aureus (MRSA) and contact precautions for MRSA-positive patients as part of routine infection control practices. The objective of this study was to determine whether nosocomial acquisition of MRSA decreased in these hospitals during an outbreak of severe acute respiratory syndrome (SARS) when barrier precautions were routinely used for all patients. DESIGN Retrospective cohort study. SETTING Three tertiary-care hospitals (a 1100-bed hospital; a 500-bed hospital; and an 823-bed hospital) and a 430-bed community hospital, each located in Toronto, Ontario, Canada. PATIENTS All admitted patients were included. RESULTS The nosocomial rate of MRSA in all four hospitals combined during the SARS outbreak (3.7 per 10,000 patient-days) was not significantly different from that before (4.7 per 10,000 patient-days) or after (3.4 per 10,000 patient-days) the outbreak (P = .30 and P = .76, respectively). The nosocomial rate of MRSA after the outbreak was significantly lower than that before the outbreak (P = .003). Inappropriate reuse of gloves and gowns and failure to wash hands between patients on non-SARS wards were observed during the outbreak. Increased attention was paid to infection control education following the outbreak. CONCLUSIONS Inappropriate reuse of gloves and gowns and failure to wash hands between patients may have contributed to transmission of MRSA during the SARS outbreak. Attention should be paid to training healthcare workers regarding the appropriate use of precautions as a means to protect themselves and patients.