[Identification of Clinical Thymidine-Dependent Small-Colony Variants of Staphylococcus aureus by Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry].

In this study, the performance of MALDI-TOF MS was evaluated for the identification of clinical thymidine-dependent small-colony variants (TD-SCVs) of Staphylococcus aureus. We performed identification of a total of 15 S. aureus TD-SCVs by using biochemical tests, 16S rRNA gene sequencing and MALDI-TOF MS analysis. Although the biochemical method using MicroScan panels could not identify all isolates due to insufficient growth in the control well. MALDI Biotyper (Bruker Daltonics) could correctly identify all of them. Two sample preparation methods, the direct transfer-formic acid method and ethanol-formic acid method, for measurement by MALDI Biotyper made no difference in results. MALDI-TOF MS is useful identification of S. aureus TD-SCVs.