Comparison of the Filamentous Fungi Library v4.0 MALDI Biotyper Platform vs MSI-2 performance for identifying filamentous fungi from liquid cultures.

Correct, rapid, and reliable filamentous fungi identification is crucial for timely diagnosis and therapy. We compared the performance of the FFLv4.0 MALDI Biotyper and MSI-2 to identify filamentous fungi from clinical isolates. We analyzed 307 clinical isolates of Aspergillus spp., Fusarium spp., and Mucorales and compared them to sequencing as the reference standard. The overall identification rates to genus (Mucorales), section (Aspergillus), and species complex (Fusarium) level were 96% (296/307) for FFLv4.0 and 78.5% (241/307) for MSI-2. By each genus, correct species identification was achieved by FFLv4.0 and MSI-2 as follows: 72.4% (165/228) and 55.3% (126/228) for Aspergillus species, 17.6% (6/34) and 38.2% (13/34) for Fusarium species, and 88.9% (40/45) and 55.5% (25/45) for the Mucorales. The rates of non-identification by FFLv4.0 and MSI-2, respectively, were 4% (9/228) and 18% (41/228) for Aspergillus spp., 0% and 17.6% (6/34) for Fusarium spp. and 4.4% (2/45) and 42.2% (19/45%) for the Mucorales. Misidentification rates by FFLv4.0 and MSI-2, respectively, were 16.2% (37/228) and 6.1% (14/228) for Aspergillus species, 67.6% (23/34) and 14.7% (5/34) for Fusarium spp., and 0% and 2.2% (1/45) for the Mucorales. The FFLv4.0 MALDI Biotyper outperformed MSI-2 in identifying filamentous fungi from liquid culture spectra.