What proportion of hospital patients colonized with methicillin-resistant Staphylococcus aureus are identified by clinical microbiological cultures?
GROUND: Most hospitals in the United States do not perform active surveillance cultures and, thus, rely on clinical microbiological cultures (CMCs) to identify patients colonized with methicillin-resistant Staphylococcus aureus (MRSA). We sought to determine what proportion of patients who are colonized with MRSA at admission are identified by CMCs during hospitalization. METHODS: From February 1998 through November 2002, patients found to be colonized with MRSA at admission by use of active surveillance cultures were identified. The proportion of colonized patients who had a CMC that was positive for MRSA, the number of CMCs performed and their type (ie, according to the anatomical site from which specimens were obtained for culture), and the number and type of CMCs that were positive for MRSA were calculated. RESULTS: Four hundred thirty-seven patients were found to be colonized with MRSA at admission, and 98 of 1,238 CMCs (7.9%; 95% confidence interval, 6.5%-9.6%) performed for 66 o
