To the Editor—A recent article by Peleg et al [1] demonstrated that methicillinresistant Staphylococcus aureus (MRSA) strains with elevated vancomycin minimum inhibitory concentrations (MICs) were significantly less virulent than strains with lower MICs. From a clinician’s perspective, 2 recent articles by Soriano et al [2] and Price et al [3] provided conflicting data regarding mortality risk associated with MRSA bacteremia caused by strains with a high vancomycin MIC (11 mg/mL). Soriano et al [2] reported an increased mortality associated with MRSA bacteremia, whereas Price et al [3] found just the opposite.

We performed a retrospective observational cohort study of patients with MRSA bacteremia from January 2002 through December 2004 in a tertiary-care hospital. Patients were prospectively followed for 3 years. Sixty-three patients with MRSA bacteremia were treated exclusively with vancomycin. Vancomycin MIC was determined by E-test with use of a 0.5 McFarland inoculum in brain-heart infusion agar. The cut off point of vancomycin MIC was 1.5 mg/mL. Thirteen (20.6%) of 63 patients had an MRSA strain with vancomycin MIC1. 5 mg/mL. The main clinical characteristics of the MRSA bacteremia episodes according to the vancomycin MIC (vancomycin MIC 1.5 mg/mL or! 1.5 mg/mL) are shown in Table 1. There were no significant differences between both groups in the time to vancomycin therapy initiation or in the duration of treatment. Patients with MRSA strains with MIC 1.5 mg/mL had