Evaluation of the Performance of ASTA MicroIDSys, a Novel Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry System, in Identification of Bacterial Clinical Isolates

Abstract

Background: We evaluated the performance of ASTA MicroIDSys (ASTA, Korea) and Bruker Biotyper (Bruker Daltonics, Germany) systems in the identification of bacterial isolates from clinical microbiology laboratory specimens during the study period. In addition, species for which the identification accuracy using MALDI-TOF MS systems was previously reported to be poor were also identified by comparing the MS results with those obtained using molecular identification. Methods: A total of 889 non-duplicated clinical isolates were included in this study. The results of ASTA MicroIDSys were compared with those of Bruker Biotyper; 16S rRNA sequencing was performed for the species for which results obtained using the two systems did not match. The sequences of rpoB, hisA, and/or recA for the clinical isolates of Acinetobacter species, Klebsiella species, and Burkholderia cepacia complex were analyzed and used as reference identifications. Results: The concordance rates for bacterial identification using ASTA MicroIDSys and Bruker Biotyper were 100% at the genus level and 98.3% at the species level for isolates belonging to the order Enterobacterales. Similarly, the concordance rates at the genus and species levels were 98.8% and 91.0% for glucose non-fermenting bacilli, 100% and 100% for gram-positive cocci, and 98.9% and 98.9% for other isolates, respectively. ASTA MicroIDSys was expected to correctly identify 97.9% of the 108,251 isolates identified in our clinical microbiology laboratory over the past 5 years. Conclusion: ASTA MicroIDSys showed excellent performance in bacterial identification for most of the clinically relevant species. Further extension of the database could improve the identification accuracy of ASTA MicroIDSys.