Abstract
Recently, many cases have been reported on treatment failure in association with methicillin-resistant S. aureus (MRSA) strains at vancomycin (VCM) minimum inhibitory concentrations (MICs) of 2.0 μg/ml. It is known that results of VCM MICs vary depending on the measurement method. In particular, in the microscan Pos Combo 3.1J panel (SIMENS), results differ between the prompt method and the manual method, which involve different methods of preparing the bacterial suspension. We studied the difference between those methods in comparison with the Broth Dilution Method using 91 strains of Staphylococcus aureus from our Laboratory Division. Data showed that the results of the manual method correlated with 81.3% of the Broth Dilution Method results, but those of the prompt method correlated with only 40.7%. In conclusion, when we measure VCM MICs using the microscan Pos Combo 3.1J panel, we should adopt the manual method.
