P417 Evaluation of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)-Bruker Biotyper Sirius for identification of invasive molds

Abstract

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM ObjectivesSusceptibility to various antifungal drugs varies between different species and subspecies within the same genus. Phenotypic identification of fungi has limitations for species-level identification. Correct identification of species and subspecies in invasive mold infections is important to initiate the appropriate antifungal therapy. Matrix Assisted Laser Desorption Ionization Time-of-Flight mass spectrometry (MALDI-TOF MS) with its proteomic analysis overcomes this limitation and helps in administering the correct anti-fungal therapy. A total of seven mold isolates from invasive fungal infections were evaluated for identification by MALDI-TOF MS and conventional morphological methods.MethodsTotal of seven isolates from invasive mold infections were identified by the conventional method of culturing specimens on Sabouraud's dextrose agar and Potato Dextrose agar with incubation at room temperature and 37°C in Biological oxygen demand (BOD) incubator. Micro-morphological identification of the fungus was done by Lacto Phenol Cotton Blue (LPCB) mount. Same isolates were processed on MALDI-TOF MS Bruker Biotyper Sirius (Bruker Daltonics, Bremen Germany) following recommended extraction protocol using ethanol absolute, acetonitrile, and 70% formic acid.ResultsAs per the below Figure.ConclusionIn four out of seven isolates phenotypic identification upto species level based on LPCB micromorphology was confirmed on MALDI-TOF MS. In the remaining three isolates we could only give a genus level identification based on LPCB mount. These three isolates were further identified upto the level of species after processing on MALDI as Aspergillus tamarii, Phaeoacremonium cinerum, and Fusarium equiseti. All mold isolates were identified with good quality mass spectra. In our experience, mold identification by MALDI-TOF MS using the Bruker Biotyper Sirius platform definitely has an edge over conventional phenotypic methods in species-level differentiation of various molds, impacting targeted antifungal management.