Identification of molds with MALDI-TOF mass spectrometry: performance of the newly developed MSI-2 application in comparison with the Bruker filamentous fungi database and MSI-1

Anne-Cécile Normand (1) , Marion Blaize (1) , Sébastien Imbert (1) , Ann Packeu (2) , Pierre Becker (2) , Arnaud Fekkar (1) , Dirk Stubbe (2) , Renaud Piarroux (3)

1 CHU Pitié-Salpêtrière [AP-HP]
2 Sciensano [Bruxelles]
3 iPLESP - Institut Pierre Louis d'Epidémiologie et de Santé Publique

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) represents a promising tool for the rapid and efficient identification of molds, but improvements are still necessary to achieve satisfactory results when identifying cryptic species. Here, we aimed to validate a new web application, MSI-2, which replaces MSI-1, an application that was built and deployed online in 2017. For the evaluation, we gathered 633 challenging isolates obtained from daily hospital practice that were first identified with DNA-based methods, and we submitted their corresponding mass spectra to three identification programs (Bruker, MSI-1 and MSI-2). The MSI-2 application had a better identification performance at the species level than MSI-1 and Bruker, reaching 83.25% correct identifications compared with 63.19% (MSI-1), 38.07% (Bruker with 1.7 threshold) and 21.8% (Bruker with 2.0 threshold). The MSI-2 application performed especially well for Aspergillus and Fusarium species, including for many cryptic species, reaching 90% correct identifications for Aspergillus species and 78% for Fusarium species compared to 69% and 43% with MSI-1. Such improvement may have a positive impact on patient management by facilitating the identification of cryptic species potentially associated with a specific antifungal resistance profile.

Mots clés: MALDI-TOF mass spectrometry; mold; online identification; MSI; database

Domaines: Microbiologie et Parasitologie

Anne-Cécile Normand, Marion Blaize, Sébastien Imbert, Ann Packeu, Pierre Becker, et al.. Identification of molds with MALDI-TOF mass spectrometry: performance of the newly developed MSI-2 application in comparison with the Bruker filamentous fungi database and MSI-1. Journal of Clinical Microbiology, 2021, 59 (10), ⟨10.1128/JCM.01299-21⟩. ⟨hal-03349849⟩