Characterization of medically important yeast Trichosporon mucoides and its close sister Trichosporon dermatis by traditional and advanced technologies.

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Characterization of medically important yeast Trichosporon mucoides and its close sister Trichosporon dermatis by traditional and advanced technologies.

J Med Microbiol. 2015 Jul 14;

Authors: Suh SO, Houseknecht JL, Grosso KM, Carrion ME

Abstract
Trichosporon dermatis is a causative agent of several mycoses in immunocompromised patients, but is often misidentified as Trichosporon mucoides due to their phenotypic resemblance. In order to evaluate the current identification keys for these species and to develop a rapid and reliable identification method, eleven strains of these yeasts were fully characterized in this study by traditional and advanced technologies. DNA sequences of the ITS, IGS 1, and D1/D2 regions identified six of the yeasts as T. dermatis which were previously known as T. mucoides, including ATCC® 204094™ that has been used as the QC strain of T. mucoides for the VITEK® 2 system and other commercial yeast identification kits. These two species could not be differentiated reliably by any previously known phenotypic keys for the species, such as growth patterns on ethylamine, phloroglucinol, and tyramine, or by the VITEK® 2 system. On the other hand, matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) proved to be a rapid and reliable identification tool for the two closely related yeasts. With newly added superspectra from fully authenticated reference strains, the VITEK® MS system using MALDI-TOF MS successfully separated strains of T. dermatis and T. mucoides at a similarity level of approximately 67% for the mass spectra data, and could identify these strains at species level with 100% accuracy in repeated tests. Further, the in vitro susceptibility results indicated that itraconazole, posaconazole, and voriconazole are more effective against both T. mucoides and T. dermatis than other antifungal agents tested.

PMID: 26296931 [PubMed - as supplied by publisher]