OBJECTIVE: To investigate whether adding rifampicin to vancomycin could cure more patients with nosocomial methicillin-resistant Staphylococcus aureus pneumonia compared with vancomycin-only. DESIGN: Prospective randomized open-label study. Setting: Medical intensive care unit in Seoul, Korea. Patients: Ninety-three of 183 patients with Gram-positive nosocomial pneumonia. Interventions: The enrolled patients with subsequently documented methicillin-resistant Staphylococcus aureus pneumonia (modified intention-to-treat population) were treated with vancomycin (1 g intravenous every 12 hrs) plus rifampicin (300 mg twice daily by mouth) (n = 41) or with vancomycin-only (n = 42). The intended treatment (at least 5 days) was completed in 30 patients in the vancomycin plus rifampicin group and 34 patients in the vancomycin-only group (per protocol population).

MEASUREMENTS AND MAIN RESULTS: The primary outcome was the clinical cure rate on day 14 of treatment. The secondary outcomes were intensive care unit mortality on days 28 and 60, and microbiological eradication on day 14. The clinical cure rate in the modified intention-to-treat population was 53.7% (22 of 41) in the vancomycin plus rifampicin group, and 31.0% (13 of 42) in the vancomycin-only group (p = .047), and the respective rates in the per protocol population were 63.3% (19 of 30) and 38.2% (13 of 34) (p = .079). The respective mortality rates were nine (22.0%) of 41 and 16 (38.1%) of 42 on day 28 (p = .151), and 11 (26.8%) of 41 and 21 (50.0%) of 42 on day 60 (p = .042). The microbiological eradication rate did not differ between groups (p = .472).

CONCLUSIONS: Vancomycin plus rifampicin seems to be more effective than vancomycin alone in the treatment of nosocomial methicillin-resistant Staphylococcus aureus pneumonia.