title: Analyses of black fungi by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS): species-level identification of clinical isolates of Exophiala dermatitidis.
abstract: Conventional mycological identifications based on the recognition of morphological characteristics can be problematic. A relatively new methodology applicable for the identification of microorganisms is based on the exploitation of taxon- specific mass patterns recorded from abundant cell proteins directly from whole-cell preparations, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This study reports the application of MALDI-TOF MS for the differentiation and identifications of black yeasts, isolated from the respiratory tracts of patients with cystic fibrosis (CF). Initial phenotypic and DNA sequence-based analyses identified these isolates to be Exophiala dermatitidis. The type strains of E. dermatitidis (CBS 207.35(T)) and other species of Exophiala were included in the MALDI-TOF MS analyses to establish the references for comparing the mass spectra of the clinical isolates of Exophiala. MALDI-TOF MS analyses exhibited extremely close relationships among the clinical isolates and with the spectra generated from the type strain of E. dermatitidis. The relationships observed between the E. dermatitidis strains from the MALDI-TOF MS profiling analyses were supported by DNA sequence-based analyses of the rRNA ITS1 and ITS2 regions. These data demonstrated the applicability of MALDI-TOF MS as a reliable, rapid and cost-effective method for the identification of isolates of E. dermatitidis and other clinically relevant fungi and yeasts that typically are difficult to identify by conventional methods.
authors: Department of Infectious Diseases, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden nahid.kondori@microbio.gu.se.
authors: Nahid
authors: N
authors: Kondori
authors: RIPAC-LABOR GmbH, D-14476 Potsdam, Germany.
authors: Marcel
authors: M
authors: Erhard
authors: Department of Infectious Diseases, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden.
authors: Christina
authors: C
authors: Welinder-Olsson
authors: Centraalbureau voor Schimmelcultures (CBS), CBS-KNAW Fungal Biodiversity Centre, 3584 CT Utrecht, Netherlands.
authors: Marizeth
authors: M
authors: Groenewald
authors: Centraalbureau voor Schimmelcultures (CBS), CBS-KNAW Fungal Biodiversity Centre, 3584 CT Utrecht, Netherlands.
authors: Gerard
authors: G
authors: Verkley
authors: Department of Infectious Diseases, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden Culture Collection University of Gothenburg, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden.
authors: Edward R B
authors: ER
authors: Moore
mesh_terms: D016000:Cluster Analysis; D003550:Cystic Fibrosis / Q000150:complications; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005093:Exophiala / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification*; D006801:Humans; D009181:Mycoses / Q000382:microbiology*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer
keywords: Exophiala dermatitidis; MALDI-TOF MS; fungi; whole-cell protein profiling