Identification of dermatophytes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. (July 2013)

• Record Type: Journal Article
• Authors: de Respinis, Sophie; Tonolla, Mauro; Pranghofer, Sigrid; Petrini, Liliane; Petrini, Orlando; Bosshard, Philipp P.
• Is Part Of: Medical mycology. Volume 51:Number 5(2013)
• Page Start: 514
• Page End: 521
• Publication Date: 2013-07
• Subjects: Medical mycology -- Periodicals; Veterinary mycology -- Periodicals; Mycology -- Periodicals; Mycoses -- Periodicals; Pathogenic fungi -- Periodicals; 616.969005
• DOI: 10.3109/13693786.2012.746476
• Languages: English
• ISSNs: 1369-3786

Abstract

<abstract> <title>Abstract</title> <p>In this study we evaluated the suitability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of dermatophytes in diagnostic laboratories. First, a spectral database was built with 108 reference strains belonging to 18 species of the anamorphic genera <italic>Epidermophyton, Microsporum</italic> and <italic>Trichophyton</italic>. All strains were well characterized by morphological criteria and ITS sequencing (gold standard). The dendrogram resulting from MALDI-TOF mass spectra was almost identical with the phylogenetic tree based on ITS sequencing. Subsequently, MALDI-TOF MS SuperSpectra were created for the identification of <italic>Epidermophyton floccosum, Microsporium audouinii, M. canis, M. gypseum</italic> (teleomorph: <italic>Arthroderma gypseum</italic>), <italic>M. gypseum</italic> (teleomorph: <italic>A. incurvatum</italic>), <italic>M. persicolor, A. benhamiae</italic> (Tax. Entity 3 and Am-Eur. race), <italic>T. erinacei, T. interdigitale</italic> (anthropophilic and zoophilic populations), <italic>T. rubrum</italic>/<italic>T. violaceum, T. tonsurans</italic> and <italic>T. terrestre</italic>. Because <italic>T. rubrum</italic> and <italic>T. violaceum</italic> did not present enough mismatches, a SuperSpectrum covering both species was created, and differentiation between them was done by comparison of eight specific peptide masses. In the second part of this study, MALDI-TOF MS with the newly created SuperSpectra was tested using 141 clinical isolates representing nine species. Analyses were done with 3-day-old cultures. Results were compared to morphological identification and ITS sequencing; 135/141 (95.8%) strains were correctly identified by MALDI-TOF MS compared to 128/141 (90.8%) by morphology. Therefore, MALDI-TOF MS has proven to be a useful and rapid identification method for dermatophytes.</p> </abstract>