ASPERGILLOSIS: AN OVERVIEW

Aspergillus produces both airborne and waterborne infections with deadly consequences depending on the species involved and the immune status of patients. Patients may remain asymptomatic for up to 18 months. The severity of aspergillosis is mainly seen in HSCT recipients with mortality up to 90%. Though aspergillosis is primarily opportunistic and lung is the primary site of infection yet deviation observed where the primary site was organs other than lungs. The major reasons behind invasion are prolonged (>3 weeks) high dose corticosteroid therapy, broad-spectrum antibiotics, CMV infection, iron overload, decreased neutrophil count (<500 cells/mm³), etc. Monoclonal technology in the form of EB-A2 and JF5 antibody can identify fungal antigen much before the appearance of clinical symptoms. Selection of a test and its success to determine fungal invasion depend on associated morbidity as galactomannan assay is more suitable in HSCT recipients rather than solid organ transplant recipients whereas PCR is specific for cancer patients with thrombocytopenia to differentiate between aspergillosis and histoplasmosis. Thorough knowledge about the neutrophil profile is required to interpret the results of CT scan and biopsy. The success of treatment depends on early and correct diagnosis as Aspergillus mimics precancerous conditions and there is considerable overlapping of symptoms between different species of Aspergillus and therapy must be species specific. Mutations in Cyp51A, L98H, M220I, F219C, and G54W are responsible for azole resistance, but the mystery of resistance did not resolve completely as certain fungal isolates show no such mutations but are resistant to antifungals; indicating the need of further research.