Performance Evaluation of Bruker Biotyper, ASTA MicroIDSys, and VITEK-MS and Three Extraction Methods for Filamentous Fungal Identification in Clinical Laboratories

Abstract

Filamentous fungi are a major cause of life-threatening infections in immuno-compromised patients; thus, rapid and accurate identification is critical. Filamentous fungal identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been demonstrated with high sensitivity and reproducibility; however, its wider application has been limited in clinical laboratories because of practical challenges such as database availability or lack of standardization. In this study, we compared the performance of the Bruker Biotyper, ASTA MicroIDSys, and Vitek MS for 84 clinical filamentous fungal isolates. Moreover, the sensitivity of three independent sample preparation methods (direct, on plate, in tube) was compared. Bruker Biotyper identified 71.43% (60/84) of isolates correctly (species, genus, or complex/group level). ASTA MicroIDSys and Vitek MS showed accuracy rates of 70.24% (59/84) and 55.95% (47/84), respectively. We found that any difference in sensitivity may be attributed to the database of the systems. In addition, the "in tube" method showed the highest sensitivity among the three methods; however, there was no statistical difference among them. For the broader application of MALDI-TOF MS for filamentous fungal identification, further studies from multiple perspectives are required.