Vancomycin versus Linezolid in the Treatment of Methicillin-Resistant Staphylococcus aureus Meningitis

Background: Vancomycin is the mainstay of treatment for methicillin-resistant Staphylococcus aureus (MRSA) meningitis. However, successful outcomes with linezolid have not been reported in a large series of patients. We conducted a single-center retrospective cohort study to compare vancomycin with linezolid in the treatment of MRSA meningitis. Methods: We extracted data and outcomes for all adult patients (age > 18 years) with culture-proved MRSA meningitis who received vancomycin or linezolid between January 2006 and June 2011. A definite diagnosis of meningitis was based on the isolation of MRSA in at least one cerebrospinal fluid (CSF) culture and findings in CSF that are typical of the infection. Linezolid was given intravenously (IV) at a dosage of 600mg q12h and vancomycin IV at 500mg q6h. Results: A total of 8 patients with MRSA meningitis (5 male, 3 female; age [mean +/- SD] 61.6 +/- 13.2 years) received vancomycin and 9 patients (7 male, 2 female; age 59.1 +/- 15.6 years) received linezolid. All isolated strains of MRSA were susceptible to both vancomycin and linezolid. The rates of microbiologic success with linezolid or vancomycin, in terms of clearance of MRSA from CSF on day 5, were 7/9 and 2/8 (p = 0.044, Fisher exact test). No severe adverse events occurred in either treatment arm of the study. One-month survival of the patients in whom treatment was successful microbiologically was 2/2 in the vancomycin-treated group and 4/7 in the linezolid-treated group. Minimum inhibitory concentration (MIC) data for vancomycin were available for 5/6 treatment failures with vancomycin, and vancomycin MIC values of these five strains were 2 mg/L. Conclusion: Analysis of the findings in the limited cohorts in our study suggests that linezolid is superior to vancomycin for treating MRSA meningitis, especially in cases in which there is a high MIC (2mg/L) for vancomycin. A clinical study involving larger cohorts may increase the evidence available in relation to this question.