Clinical and Epidemiological Profile of Pathogenic Moulds Causing Systemic Mycoses in Patients Receiving Immunosuppressive Therapy and Their Antifungal Susceptibility in a Tertiary Care Hospital

Abstract

Background: Invasive mould infections remain a serious problem in immunosuppressed patients because the disease often evolves rapidly, presents with nonspecific features, and demands early antifungal selection.

Aim: To describe the clinical and epidemiological profile of pathogenic moulds causing systemic mycoses in patients receiving immunosuppressive therapy and to assess their antifungal susceptibility pattern.

Materials and Methods: This prospective cross-sectional study was conducted in a tertiary care teaching hospital in Chennai over 12 months in the year 2022.Three hundred immunosuppressed adults with suspected systemic mycosis were evaluated using conventional mycological methods. Mould isolates were identified by culture characteristics and lactophenol cotton blue microscopy. Antifungal susceptibility testing was performed by the CLSI M38-A2 broth microdilution method.

Results: Systemic mycoses were confirmed in 28 of 300 patients, yielding an incidence of 9.3%. Men constituted 67.9% of confirmed cases, and the 41-60-year age group was most affected (60.7%). Thoracic Medicine contributed the largest share of cases (39.3%). Aspergillus spp. were the predominant isolates (57.1%), followed by Mucor spp. (25.0%) and Rhizopus spp. (17.9%). All proven mould infections occurred among corticosteroid-exposed COVID-19 patients, with a significant association between steroid regimen and proven mycosis within that subgroup (chi-square=24.7411, p=0.000001). Amphotericin B showed 100% in-vitro susceptibility across all isolates. Voriconazole retained excellent activity against Aspergillus spp., whereas itraconazole and posaconazole showed reduced activity against Mucorales.

Conclusion: Systemic mould infections in immunosuppressed patients in this setting were driven mainly by Aspergillus spp. and Mucorales, with a clear concentration among steroid-exposed patients. Species-level identification and routine antifungal susceptibility testing remain important for timely and appropriate therapy.