Identification of fungal clinical isolates by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry

Background. Recently, bacterial identification by MALDI-TOF MS has acquired a high relevance in terms of speed and reliability. Conventional mycological identification has some disadvantages: it is frequently slow, reliability is sometimes low, and an extensive experience is required. The risk population for fungal infections, and therefore their clinical significance has progressively increased in recent years. Methods. 153 yeast and mould clinical isolates were analyzed by MALDI-TOF MS and conventional identification. When both methods were discrepant to the genus or species level, ITS-2 sequencing was performed. Results. The correlation in yeasts identification between conventional identification methods and MALDI-TOF MS was extremely high (99.2% to the species level and 1000% to the genus level). The only discrepancy was checked by ITS-2 sequencing and confirmed the MALDI-TOF identification. The correlation in moulds identification was more heterogeneous. 68.70/0 of the isolates showed correlation at least to the genus level and 40.6% to the species level. Therefore, the correlation between conventional identification and MALDI-TOF MS in fungal identification was, In whole, 87% to the species level, and 93.5% to the genus level. Conclusions. Identification of fungi by MALDI-TOF MS is reliable and shows potential advantages over conventional identification methods.