Prevalence of methicillin-resistant Staphylococcus aureus colonization in surgical patients, on admission to a Welsh hospital.

Nosocomial infection with methicillin-resistant Staphylococcus aureus (MRSA) is on the increase and expensive to treat. Because surgical wound infection is one of the most frequent MRSA-induced infections with often disastrous consequences, it was decided to estimate the incidence and risk factors of MRSA colonization in surgical patients. All patients admitted to general surgical and orthopaedic wards were studied prospectively. At the time of admission, a detailed questionnaire was completed, nasal swabs and swabs of any pre-existing wound sites in each patient were sent for culture. Of 430 patients studied, 23 patients were positive for MRSA on admission. The prevalence of MRSA colonization in this study was 5.3% of whom 15 (65%) were nasal carriers and eight (35%) had MRSA colonization elsewhere. All nasal MRSA carriers had at least one documented hospital admission in the preceding year. Among the MRSA-positive patients, 10 (43%) either were admitted directly from, or had been previously admitted to, a nursing home. MRSA remains mainly a hospital-acquired infection although a significant proportion is acquired in the community. The risk factors identified were previous hospital admission, patients from nursing homes, male and aged over 70. Copyright 2002 The Hospital Infection Society.