Comparative study of bacterial identification using VITEK MS and VITEK2 in routine clinical microbiological analysis

Abstract

There have been many reports of bacterial identification using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system. However, studies of the bacterial identification using the most recent MALDI-TOF MS system (VITEK MS) compared with that using a conventional biochemical identification system are scarce. We compared VITEK MS with VITEK2 (a conventional biochemical identification system) in the identification of 314 clinical isolates. The identification rate at the genus level for VITEK MS (93.6%) was significantly lower than that for VITEK2 (95.9%); however, the identification rate at the species level for VITEK MS (88.9%) was significantly higher than that for VITEK2 (85.0%). VITEK MS might fail to identify enterobacteria owing to inadequate sampling techniques in some cases or insufficient databases of these bacteria. It is necessary for bacterial identification using VITEK MS to take findings of Gram staining and bacterial colonies into consideration. The identification rate for VITEK MS will be increased by improving sampling techniques and upgrading databases.