Clinical Outcomes of Linezolid vs Vancomycin in Methicillin-Resistant Staphylococcus aureus Ventilator-Associated Pneumonia

Background: Vancomycin has been the treatment standard for methicillin-resistant Staphylococcus aureus (MRSA) infections, but clinical efficacy is limited. We report outcomes of a cohort with MRSA ventilator-associated pneumonia (VAP) treated with vancomycin vs linezolid. Methods: Retrospective analysis of 113 participants with MRSA VAP confirmed by bronchoscopy who have been initiated on therapy with either vancomycin or linezolid within 24 hours after bronchoscopy and completed ≥7 days of therapy during their hospitalization from July 2003 to June 2007. The primary endpoints were hospital survival and clinical cure, defined as resolution of signs and symptoms of VAP or microbiological eradication after completion of therapy along with clinical pulmonary infection score (CPIS) ≤6 at day 7 of therapy. Results: At hospital discharge, 23/27 (85.2%) of linezolid and 72/86 (83.7%) of vancomycin recipients had survived (P = .672). In comparison to linezolid recipients, the adjusted odds ratio (OR) for survival was 0.72 (95% confidence interval [CI]: 0.16-3.27) with vancomycin therapy. Clinical cure was achieved in 24/27 (88.9%) of linezolid and 63/86 (73.3%) of vancomycin recipients (P = .066). Compared to linezolid recipients, the adjusted OR for clinical cure was 0.24 (95% CI: 0.05-1.10) with vancomycin therapy. Survival and clinical cure did not differ significantly between vancomycin recipients with trough level ≥15 and <15 μg/mL, respectively. Conclusions: Our results suggested no survival benefit but a trend toward higher cure rate with linezolid therapy. The optimal treatment of MRSA VAP requires further study through randomized, controlled trials.