P441 Molecular identification, genotyping, and antifungal susceptibility of Trichosporon species isolated from clinical samples of patients at various parts of the Indian subcontinent

POSTER SESSION 3, SEPTEMBER 23, 2022, 12:30 PM - 1:30 PM: OBJECTIVES: (1) To study mycological characteristics of strains belonging to Trichosporon and its related genera obtained from clinical samples of patients from India. (2) Molecular identification by intergenic spacer (IGS) region 1 sequencing of the rDNA locus. (3) Genotyping of the major causative agent, T. asahii, and its in vitro drug susceptibility testing. MATERIALS AND METHODS: A total of 55 clinical isolates of Trichosporon species were collected from NCCPF (National culture collection of pathogenic fungi) PGIMER, Chandigarh along with different health institutions of India. These isolates were recovered from urine, blood, sputum, nail, tissue biopsy, pleural fluid, hair, BAL, and wound discharge over a period of 12 years (2006–2018). The isolates were molecularly characterized and genotyped using IGS-1 region sequencing. In vitro drug susceptibility testing of the isolates was performed against amphotericin-B, fluconazole, itraconazole, voriconazole, and posaconazole according to the CLSI M27-A3 guidelines (CLSI 2008). RESULTS: Predominant underlying risk factors identified were presence of an indwelling catheter, use of broad-spectrum antibiotics, and presence of comorbid conditions such as diabetes, hypertension, and anemia. A total of 47 (85%) of the 55 isolates were identified as T. asahii, 6 were T. inkin (11%), and 2 were Cutaneo Trichosporon dermatis (3.6%). Trichosporon asahii genotype III (22; 41%) was the most common type, followed by genotype IV (12; 22%), I (8; 15%), and VII (2; 4%). In addition to the 15 known T. asahii genotypes, one novel genotype was identified in this study. Indian T. asahii isolates showed high MIC ranges to amphotericin B (0.06-4 μg/l) and fluconazole (0.25-64 μg/l). Relatively low MIC ranges were found in the case of voriconazole (0.03-1 μg/l), Posaconazole (0.06-1 μg/l), and itraconazole (0.06-1 μg/l). Voriconazole appeared to be the most active drug in maximum T. asahii isolates. The MICs for all the drugs were comparatively lower in the case of non-T. asahii strains. CONCLUSION: Trichosporon asahii remains the most common etiology of Trichosporonosis in India and presents a challenge for both diagnosis and treatment. With increasing drug resistance, therapeutic options are limited, and antifungal regimens with triazoles especially voriconazole appear to be the best. Accurate timely identification, removal of indwelling catheters/central venous lines, and voriconazole-based treatment along with control of underlying conditions were associated with favorable outcomes. Identification of the novel genotype has epidemiological implications and requires further work up.