Risk Factors,Diagnosis and Outcome of Proven and Probable Invasive Trichosporonosis in a Tertiary Care Hospital: A Cross-sectional Analytical Study

Abstract

Introduction: Trichosporon species are basidiomycetous yeast like fungus that is ubiquitous in the environment. They form part of the normal flora in humans. In recent years, they have been causing invasive infections, especially in the immunocompromised hosts. Disseminated cases including trichosporonemia can rapidly progress, leading to increased morbidity and mortality. Aim: To diagnose and identify risk factors and outcomes of proven and probable invasive Trichosporon species infections. Materials and Methods: This cross-sectional analytical study was done at Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India, over a period of one year (March 2023 till February 2024). All the clinical samples sent for routine diagnostics to the laboratory during the study period and archived samples were included (Total isolates, n=60). European Organisation for Research and Treatment of Cancer/Invasive Fungal Infection Cooperative Group (EORTC/IFICG) and the National Institute of Allergy and Infectious Disease/Mycoses Study Group (NIAID/MSG) definitions were used to categorise samples as proven invasive and probable invasive trichosporonosis. Phenotypic characterisation was done by colony morphology on Sabouraud Dextrose Agar (SDA), Gram stain, Dalmau technique and urea hydrolysis. Genotypic characterisation was done by Trichosporon genus specific and Trichosporon asahii specific Polymerase Chain Reaction (PCR). The reference strains used as quality control were Trichosporon asahii Microbial Type Culture Collection (MTCC) 6179, Trichosporon jirovecii MTCC 9036 and Candida albicans American Type Culture Collection (ATCC) 90028. All statistical analysis was performed using Microsoft Excel (2016) and descriptive statistics were presented as numbers and percentages. Results: All the 60 (100%) isolates were characterised as Trichosporon asahii. Amongst them 4 (6.7%) were categorised as proven invasive trichosporonosis and 56 (93.3%) were probable invasive trichosporonosis. Some important risk factors for invasive disease were Intensive Care Unit (ICU) admission, antibiotic usage, diabetes and hypertension. All 4 (6.3%) proven cases were isolated from blood and 2 (50%) amongst them succumbed to the disease. Amongst the probable cases, 16 (28.6%) succumbed to the disease. Conclusion: Invasive infections caused by Trichosporon species have high mortality especially amongst immunocompromised hosts. Hence, identification at an early stage by appropriate diagnostic methods and initiating appropriate antifungal agents can result in better outcome of the patient.

Keywords

• fungaemia
• invasive fungal infection
• trichosporon species