Trichosporon inkin biofilms produce extracellular proteases and exhibit resistance to antifungals.

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Trichosporon inkin biofilms produce extracellular proteases and exhibit resistance to antifungals.

J Med Microbiol. 2015 Aug 25;

Authors: Cordeiro RA, Serpa R, Alexandre CF, Marques FJ, de Melo CV, Franco JD, Evangelista AJ, de Camargo ZP, Brilhante RS, Rocha MF, Moreira JL, Bandeira TJ, Sidrim JJ

Abstract
The aim of this study was to determine experimental conditions for in vitro biofilm formation of clinical isolates of T. inkin - an important opportunistic pathogen in immunocompromised patients. Biofilms were formed in microtiter plates in three different media (RPMI, Sabouraud and Cled), with inocula of 104, 105 or 106 cells/mL, at pH 5.5 and 7.0, at 35°C and 28°C, under static and shaking conditions for 72 h. Growth kinetics of biofilms were evaluated at 6, 24, 48 and 72 h. Biofilm milieu analysis were assessed by counting viable cells and quantification of nucleic acids released into biofilm supernatants. Biofilms were also analyzed regarding proteolytic activity and antifungal resistance against amphotericin B, caspofungin, fluconazole, itraconazole and voriconazole. Finally, ultrastructural characterization of biofilms formed in microtiter plates and catheter disks was performed by scanning electron microscopy. Higher biofilm formation was observed with starter inocula of 106 cells/mL, in pH 7.0 at 35°C and 80 rpm, in both RPMI and Sabouraud media. Growth kinetics showed increase of both viable cells and biomass with increasing incubation time, with maximum production at 48 h. Biofilms were able to disperse viable cells and nucleic acids into the supernatant throughout the developmental cycle. T. inkin biofilms produced more protease than planktonic cells and showed high tolerance to amphotericin B, caspofungin and azole derivatives. Mature biofilms were formed by different morphotypes, such as blastoconidia, arthroconidia and hyphae, in a strain-specific manner. The present article details the multicellular lifestyle of T. inkin and provides perspectives for further research.

PMID: 26310576 [PubMed - as supplied by publisher]