Outbreak among HIV-infected patients of Staphylococcus aureus resistant to cotrimoxazole and methicillin

OBJECTIVE: To describe an outbreak of trimethoprim-sulfamethoxazole (cotrimoxazole)-resistant and methicillin-resistant Staphylococcus aureus (CMRSA) in a unit housing patients infected with the human immunodeficiency virus (HIV). DESIGN: Prospective study involving patients colonized or infected with CMRSA. PATIENTS: 15 hospitalized patients with cultures positive for CMRSA. METHODS: Isolates of CMRSA were collected and characterized. Molecular typing of the epidemic strains was carried out after total DNA extraction by restriction endonuclease analysis and random amplification of polymorphic DNA. RESULTS: The epidemic was brought under control with the reinforcement of nosocomial transmission measures and with systematic nasal decontamination with mupirocin of all patients admitted to the HIV unit. Molecular typing techniques showed the existence of two epidemic strains: strain A was present in the 12 patients admitted to the HIV unit and strain B in the remaining 3 patients hospitalized elsewhere. CONCLUSIONS: Cotrimoxazole may no longer be a reliable and effective alternative for glycopeptides in patients with infection caused by MRSA strains, and HIV units should be particularly alert for CMRSA strains.