Rapid Diagnosis of Invasive Fungal Infections Caused by Candida and Aspergillus Species in Patients Admitted to Intensive Care Unit of a Tertiary Care Hospital

Author(s): Shaila Akhtar, Shaheda Anwar, Ahmed Abu Saleh

Introduction: Invasive fungal infections (IFI) are common nosocomial infections in immunosuppressed individuals. Rapid diagnosis of IFIs is important to support the growing number of at-risk patients and standardize the treatment guidelines. The study aimed to assess the role of serum 1,3-β-D-Glucan (BDG) and galactomannan (GM) biomarkers and real-time PCR in the rapid diagnosis of IFIs.

Method: It was a cross-sectional and observational study. A total of 60 peripheral venous blood samples were collected from clinically suspected IFI patients from the intensive care unit (ICU) of Bangabandhu Sheikh Mujib Medical University (BSMMU). The study was conducted from December 2022 to August 2023.

Result: Out of 60 clinically suspected IFI patients, 12 (20%) were positive for fungus in blood culture, of which Candida species accounted for 11 (18.33%) and Aspergillus species accounted for 1 (1.67%). Using serum biomarkers (GM and BDG), 46.7% of patients were positive for the BDG assay, and 20.0% of patients were positive for the GM detection assay. Using real-time PCR, Candida species (C. albicans, C. parapsilosis, C. glabrata, C. krusei) were detected in 24 (40.0%) cases and Aspergillus fumigatus were detected in 14 (23.33%) cases. The agreement between real-time PCR and serum biomarkers was 81.67% and the kappa value was 0.639, which was considered good. The sensitivity of GM, BDG, and real-time PCR were 67.65%, 92.00%, and 92.00% respectively. The specificity of GM, BDG, and real-time PCR were 100.00%, 80.77%, and 58.34% respectively.

Conclusion: Serum GM and BDG biomarkers and PCR are promising and highly sensitive tests for rapidly diagnosing at-risk patients suspected of having invasive fungal infections.