RESUMO
BACKGROUND: The purpose of this study was to survey the nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA) among the patients admitted in a medical intensive care unit (MICU) and analyze risk factors associated with the colonization. METHODS: The study was carried out on patients admitted into the MICU in a 1,250-bed tertiary care university hospital from January through December 2006. Nasal surveillance cultures were obtained from patients within 24 hours of admission to the unit. Data were analyzed retrospectively by the review of medical records. RESULTS: A total of 312 patients were screened with active nasal cultures; 36 patients (11.6%) were positive for MRSA. Of these, 22 (7.1%) were positive in the nasal cultures only and 14 (4.5%) were positive in the cultures of other specimens (13, sputum; 1, joint fluid) in addition to the nasal swabs. Among the risk factors for MRSA nasal colonization were sex (man), route of admission (from other ICUs or wards), a history of ICU admission during the recent 12 months, and prolonged hospital days in ICU. CONCLUSION: MRSA nasal carrier rate was found higher in this study than in those reported in the literature. Most of the patients colonized with MRSA in the nostril were not colonized with the organism elsewhere in the body. Whether or not active surveillance for MRSA should be performed would depend on the nasal colonization rate of the patients at the time of admission to the ICU.