PROSPECTIVE-STUDY OF INFECTION, COLONIZATION AND CARRIAGE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS IN AN OUTBREAK AFFECTING 990 PATIENTS

In the three years between November 1989 and October 1992, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) affected 990 pa tients at a university hospital. The distribution of patients with car riage, colonization or infection was investigated prospectively. Nosoc omial acquisition was confirmed in at least 928 patients, 525 of whom were identified from clinical specimens as being infected (n = 418) or colonized (n = 107) by MRSA. An additional 403 patients were identifi ed from screening specimens, of whom 58 subsequently became infected a nd 18 colonized. Screening of the nose, throat and perineum detected 9 8 % of all carriers. Of the 580 infections in 476 patients, surgical w ound, urinary tract and skin infections accounted for 58 % of the infe ctions. Of the 476 infected patients, death was attributable to MRSA i nfection in 13 %. Colonization with MRSA was found in 127 patients and 42 % of 165 colonized sites were the skin. Auto-infection from nasal carriage or cross-infection, probably via staff hands, seemed to be th e most common mode of acquisition of MRSA infections.