We read with interest the article by Hidayat et al1 that assessed the efficacy of vancomycin for the treatment of MRSA achieving unbound target serum trough levels of 4 or more times the minimal inhibitory concentration (MIC). The authors found that high MIC (1.5-2.0 μg/mL) was an independent predictor of poor clinical response regardless of the achievement of the aimed vancomycin trough levels.1 However, besides the issue of the heteroresistance to vancomycin that was not assessed in the study, but was properly addressed in the “Comment” section, there are some important points not considered by the authors that could potentially determine biased results.
Faulhaber G, Zavascki A, Fuchs SC. Is High Minimal Inhibitory Concentration of Vancomycin a Predictor of Poor Response in MRSA Infections?. Arch Intern Med. 2007;167(11):1206-1207. doi:10.1001/archinte.167.11.1206-b