Mucorales and Mucormycosis

Abstract

Mucorales are thermotolerant opportunistic fungi abundantly present in the environment, and morphologically characterized by broad aseptate hyphae. The fungi can grow easily and rapidly on growth media. The taxonomy of those fungi is undergoing evolution and 38 species have been implicated in human disease “mucormycosis.” Rhizopus arrhizus is the most common species of mucormycosis worldwide, and there exists geographical variation in the distribution of other agents. Tissue necrosis with angio-invasion is the hallmark of the disease. The incidence of mucormycosis has increased globally over the past two decades, the highest being from China, India, Mexico and Pakistan. The clinical types of mucormycosis have been described with involvement of specific anatomical sites– rhino-orbital-cerebral being the most common, followed by pulmonary, cutaneous, gastro-intestinal, and disseminated forms. Though specific risk factors are strongly associated with clinical types, hematological malignancy serves as the most important risk factor in developed countries, and diabetes mellitus in developing countries. Early diagnosis is crucial for prompt management, as the disease has high morbidity and mortality. Combined clinical, radiological, microbiological and histopathological tools are needed for timely diagnosis. Optimal management requires a combination of surgical resection of necrotic tissue, antifungal therapy and correction of underlying condition.