Identification of Trichosporon species using two methods and determination of their antifungal susceptibility

Purpose: Trichosporon species are part of the human microbiota. However, their presence in urine cultures may indicate invasive infection, particularly in immunocompromised individuals. This study aimed to identify Trichosporon spp. isolated from urine cultures of hospitalized patients at the species level and to determine their antifungal susceptibility profiles.Materials and Methods: Urine samples sent to the microbiology laboratory between June 1 and December 30, 2021, were cultured using standard microbiological methods. Yeast isolates suspected as Trichosporon spp. based on colony morphology and urease positivity were identified using the BD Phoenix™ 100 automated system and MALDI-TOF MS.Results: Trichosporon spp. was isolated from 29 of 16,011 urine samples (0.18%). Using the BD Phoenix™ Yeast ID system, 22 (75.9%) isolates were identified as Trichosporon asahii (T. asahii) and 7 (24.1%) as Trichosporon inkin (T. inkin), whereas all isolates were identified as T. asahii by MALDI-TOF MS. Antifungal susceptibility testing showed the lowest MIC values for voriconazole (MIC₅₀: 0.125 µg/ml; MIC₉₀: 0.25 µg/ml) and the highest MIC values for fluconazole (MIC₅₀: 32 µg/ml; MIC₉₀: >128 µg/ml).Conclusion: Antifungal susceptibility testing may contribute to guiding antifungal therapy and epidemiological surveillance. The BD Phoenix™ system may be useful for genus-level identification. However, further studies with molecular confirmation are required to assess species-level accuracy.