[Epidemic outbreak of methicillin-resistant Staphylococcus aureus in a general hospital. Preliminary report]

Abstract

The incidence of MRSA infections in Spain had remained in a low level through the years, being MRSA usually less than 1.5% of all S. aureus isolates. Since October 1988, we have detected in our hospital a MRSA outbreak. The epidemic started in the surgical wards, and spread through the rest of the institution. The incidence of cases was higher in the ICU's, areas that act as "multipliers" of the outbreak. In spite of standard control measures, the total number of patients with MRSA was 245 in April 1990. We studied prospectively a sample of 100 MRSA patients: thirty-six percent were colonized and 46% infected. The more common source of infection was the lower respiratory tract and primary bacteremia. The infection-related mortality was 30%. Our MRSA strain belong to phage type III, and shows a characteristic multiple antibiotic resistant pattern, the MRSA strain is sensitive to vancomycin, fusidic acid, phosphomycin and cotrimoxazole. Over the entire outbreak period, the MRSA strain developed resistance to rifampin, imipenem-cilastatin and ciprofloxacin. In spite of all control measures implemented, the outbreak can not have been totally controlled, and MRSA is now an endemic pathogen in our institution. Therefore, major changes in therapeutic approach to nosocomial infections have been since then introduced.