Background
Currently, three commercial in vitro diagnostic matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) systems are widely used in clinical laboratories. The ASTA MicroIDSys system (ASTA Inc, South Korea) is a newly developed MALDI‐TOF MS system used for the identification of pathogenic microorganisms. In the present study, we assessed the performance of the ASTA MALDI‐TOF MS system for the identification of pathogenic yeast from clinical samples.
Methods
We tested 284 clinical yeast isolates from various clinical specimens using ASTA MALDI‐TOF MS, and the results were compared with those using molecular sequencing of the ITS or D1‐D2 regions of rDNA and biochemical assays.
Results
A total of 284 isolates were tested and found to be distributed across 14 species including Candida albicans (n = 100) and other yeast species (n = 184). ASTA MALDI‐TOF MS correctly identified 95.1% (270/284) of the yeast species compared to molecular sequencing. Among them, 262 isolates showed acceptable MALDI‐TOF MS scores (≥140), and 98.1% (257/262) isolates were identified correctly. In addition, among 22 isolates with a MALDI‐TOF MS score <140, 59.1% (13/22) of the isolates showed concordance with molecular typing at the species level. Clustering analysis revealed the effectiveness of the new MALDI‐TOF MS system for the identification of yeast species.
Conclusions
ASTA MALDI‐TOF MS showed high accuracy in the identification of yeast species; it involves facile sample preparation and extraction procedures. ASTA MALDI‐TOF MS is expected to be useful for yeast identification in clinical microbiology laboratories due to its reliability and cost‐effectiveness.