Mucormycosis in COVID-19: A clinico-microbiological dilemma

Abstract

Mucormycosis, a fungal infection caused by microorganisms in the phylum Glomeromycota, has been reclassified from a rare disease to an emerging pathogen. These fungi are ubiquitous, mainly found in soil and decaying organic matter. Globally, mucormycosis incidence ranges from 0.005 to 1.7 per million people, while in India, it is 140 per million. Known as Zygomycosis, it primarily affects individuals with uncontrolled diabetes, undergoing chemotherapy, or suffering from chronic illnesses. Infection occurs through inhalation or ingestion of spores, impacting sinuses, orbit, brain, or lungs, and can be fatal if untreated. The most common form is Rhino-orbito-cerebral, followed by Pulmonary mucormycosis. COVID-19 associated Mucormycosis (CAM) was prominent during the second wave, with a mortality rate of 31–50%. Contrary to the misnomer "Black fungus," these fungi have transparent hyaline ribbon-like hyphae and invade blood vessels, leading to extensive necrosis (Black eschar). Diagnosis involves biopsy and fungal staining (KOH mount), with Liposomal amphotericin B as the preferred early treatment. Preventing COVID-associated mucormycosis requires addressing underlying risk factors, better glycemic control in diabetic patients, appropriate use of systemic corticosteroids, and avoiding unnecessary antibiotics, antifungals, and immunomodulators. This review aims to understand the microbiology, clinicopathogenesis, and prevention strategies of mucormycosis, especially during the COVID-19 pandemic.