title: Use of matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of molds of the Fusarium genus.
abstract: The rates of infection with Fusarium molds are increasing, and a diverse number of Fusarium spp. belonging to different species complexes can cause infection. Conventional species identification in the clinical laboratory is time-consuming and prone to errors. We therefore evaluated whether matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a useful alternative. The 289 Fusarium strains from the Belgian Coordinated Collections of Microorganisms (BCCM)/Institute of Hygiene and Epidemiology Mycology (IHEM) culture collection with validated sequence-based identities and comprising 40 species were used in this study. An identification strategy was developed, applying a standardized MALDI-TOF MS assay and an in-house reference spectrum database. In vitro antifungal testing was performed to assess important differences in susceptibility between clinically relevant species/species complexes. We observed that no incorrect species complex identifications were made by MALDI-TOF MS, and 82.8% of the identifications were correct to the species level. This success rate was increased to 91% by lowering the cutoff for identification. Although the identification of the correct species complex member was not always guaranteed, antifungal susceptibility testing showed that discriminating between Fusarium species complexes can be important for treatment but is not necessarily required between members of a species complex. With this perspective, some Fusarium species complexes with closely related members can be considered as a whole, increasing the success rate of correct identifications to 97%. The application of our user-friendly MALDI-TOF MS identification approach resulted in a dramatic improvement in both time and accuracy compared to identification with the conventional method. A proof of principle of our MALDI-TOF MS approach in the clinical setting using recently isolated Fusarium strains demonstrated its validity.
authors.affiliation: Service of Mycology and Aerobiology, BCCM/IHEM Fungal Collection, Scientific Institute of Public Health, Brussels, Belgium david.triest@wiv-isp.be.
authors.forename: David
authors.initials: D
authors.lastname: Triest
authors.affiliation: Service of Mycology and Aerobiology, BCCM/IHEM Fungal Collection, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Stubbe
authors.affiliation: Service of Biomonitoring, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: De Cremer
authors.affiliation: Department of Microbiology and Infection Control, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Denis
authors.initials: D
authors.lastname: Piérard
authors.affiliation: Laboratoire de Parasitologie-Mycologie, APHM, CHU Timone-Adultes, Marseille, France Aix-Marseille Université, UMR MD3 IP-TPT, Marseille, France.
authors.forename: Anne-Cécile
authors.initials: AC
authors.lastname: Normand
authors.affiliation: Laboratoire de Parasitologie-Mycologie, APHM, CHU Timone-Adultes, Marseille, France Aix-Marseille Université, UMR MD3 IP-TPT, Marseille, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Piarroux
authors.affiliation: Service of Mycology and Aerobiology, BCCM/IHEM Fungal Collection, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Monique
authors.initials: M
authors.lastname: Detandt
authors.affiliation: Service of Mycology and Aerobiology, BCCM/IHEM Fungal Collection, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Marijke
authors.initials: M
authors.lastname: Hendrickx
mesh_terms: D001530:Belgium; D060585:Fusariosis / Q000175:diagnosis / Q000382:microbiology; D005670:Fusarium / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification*; D006801:Humans; D008828:Microbiological Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013997:Time Factors