Genotyping, antifungal susceptibility testing, and biofilm formation of Trichosporon spp. isolated from urine samples in a University Hospital in Bangkok, Thailand

The basidiomycetes yeast Trichosporon is widespread in the natural environment, but can cause disease, mainly in immunocompromised patients. However, there have been only few studies about this infection in Thailand. In this study, we characterized 53 Trichosporon spp. isolated from urine samples from patients admitted to a single hospital in Bangkok, Thailand over a one-year period from 2019 to 2020. The strains were identified using colony morphology, microscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and nucleotide sequence analysis of intergenic spacer 1 (IGS1). Fifty-one isolates were Trichosporon asahii, and the remaining isolates were Trichosporon inkin and other Trichosporon species. Three genotypes of IGS1-1, 3, and 7 were observed among T. asahii. The sensitivity of the yeasts to the antifungal drugs amphotericin B, fluconazole, and voriconazole ranged from 0.25 to >16 jig ml-1, 0.5-8 jig ml-1, and 0.01-0.25 jig ml-1, respectively. We investigated biofilm formation by the isolates, and no biofilm production was found in one isolate, low biofilm production in forty-four isolates, and medium biofilm production in six isolates. T. inkin produced biofilms at low levels, and Trichosporon spp. produced biofilms at medium levels. This research increases our understanding of the molecular epidemiology of Trichosporon spp. isolated from one university hospital in Bangkok, Thailand, and reveals their genetic diversity, antifungal susceptibility profiles, and capacity for in vitro biofilm production.