Abstract:

Objective To evaluate the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS） ASTA MicroIDSys with CoreDB database（MicroIDSys system） and Bruker Biotyper MS with DB2969 database（Biotyper system） in clinical microbial identification. Methods A total of 934 microorganisms and 5 standard isolates of 28 genera，70 species or species complexes were included from 2012 to 2020 in the Second Affiliated Hospital of Zhejiang University School of Medicine. The control method for microbial identification was performed with a direct smear method，and measured spectra were analyzed using respective software. Polymerase chain reaction（PCR） and sequencing were used as reference methods if either MALDI-TOF MS system could not identify the isolates or had discrepant results. The result accuracy was evaluated. Results Five standard isolates were accurately identified in species level by the 2 MALDI-TOF MS systems. Of 934 clinical isolates，898 isolates（96.1%） were identified correctly by MicroIDSys system，11 isolates had no identification results，and 25 isolates were misidentified（identified as the other species in genus level）. The Biotyper system identified correctly 918 isolates（98.3%），6 isolates identified in genus level，2 isolates of Chromobacterium haemolyticum showed “no identification”，and 6 isolates were misidentified. Conclusions The performance of MicroIDSys system was comparable to that of Biotyper system for the identification of clinical microorganisms. However，rare and easily confused bacterial species are challenging.

Key words: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Clinical microbiology, Microbial identification, Performance evaluation