Investigation of virulence factors and antifungal susceptibilities of genotype 1 and 3 Trichosporon asahii strains

Thesis Type: Doctorate

Institution Of The Thesis: Uludağ Üniversitesi, Turkey

Approval Date: 2015

Thesis Language: Turkish




Investigation of Virulence Factors and Antifungal Susceptibilities of Genotype 1 and 3 Trichosporon asahii Strains. In this study, we aimed to investigate the virulence factors and susceptibility to antifungal agents of Trichosporon asahii strains. Acid proteinase, phospholipase, esterase enzyme activities, epitelial adhesion, cell surface hydrophobicity and slime production of a total of 21 Trichosporon asahii strains from urine, blood and plevra fluid were investigated. In this study, in none of the 21 strains acid proteinase and phospholipase acitivities could be detected, while all were found to be esterase positive. Cell surface hydrophobicity were found between 76% and 100% by using microspheres assay. Adhesive properties by the binding to epitelial cells were between 51%-287%. Establishing the production of slime, modified tube assay was performed. 52.4% of strains were found to be moderate producers (++), 28.6% of strains were weakly positive (+) and 19% of strains were defined as strongly positive producers. In vitro activities of amphotericine B, fluconazole, itraconazole, voriconazole and caspofungine against 21 isolates of T asahii were determined by the CLSI M27-A2 reference microdilution method and Etest method. All isolates exibited amphotericin B MICs ≥2.0 µg/mL. Itraconazole and voriconazole were the most potent agents in vitro against all isolates, particularly voriconazole. The echinocandin, caspofungin, demonstrated no activity against T asahii. Since the current data on virulence factors and antifungal susceptibilites of T asahii is insufficient already, these results may contribute to the present data in the literature.