Bacteremia due to methicillin-resistant Staphylococcus aureus

During a three-year period, Staphylococcus aureus phage type D11/83A/85 that was resistant to methicillin, cephalothin, and multiple aminoglycosides was recovered from 260 infected patients in an urban general hospital in Cincinnati, Ohio. This methicillin-resistant S. aureus (MRSA) was recovered from 30% of all blood cultures positive for S. aureus and represented 50% of all episodes of nosocomial bacteremia due to S. aureus. Bacteremia due to MRSA occurred most often in surgical patients (especially burn patients), occurred late in hospitalization, and was recovered frequently from wounds and intravascular catheters. Infection with S. aureus was the direct cause of death of 44% of the patients with bacteremia due to MRSA. Nine of 10 MRSA-infected patients who were treated with vancomycin alone responded to therapy compared with seven of 15 who were treated with other antistaphylococcal antibiotics (P less than 0.05). The present study defines the epidemiologic characteristics of bacteremia due to MRSA, demonstrates the virulence of MRSA, and proves that vancomycin is effective as therapy.