mucorales

Mucorales is an order of fungi traditionally grouped with the Zygomycetes and more recently placed in the phylum Mucoromycota. It comprises several genera, including Rhizopus, Mucor, Lichtheimia (formerly Absidia), Rhizomucor, and Cunninghamella. Members are widespread in soil, decaying vegetation, and stored foods, where they mostly function as saprotrophs. Some species are important in food production and fermentation, while others are notable as opportunistic human and animal pathogens.

Morphology and reproduction in Mucorales are characterized by rapidly growing, broad, coenocytic hyphae. The hyphae are typically sparsely septate and produce sporangia at the tips of sporangiophores. Asexual reproduction occurs via sporangiospores released from sporangia; sexual reproduction occurs through zygospores formed inside zygosporangia when compatible mating types meet. In several genera, rhizoids anchor sporangiophores to the substrate.

Ecology and distribution: Mucorales occur globally in soil, decaying plant matter, and decaying food products. They can colonize wounds and medical devices in clinical settings, sometimes leading to nosocomial contamination of environments and supplies.

Pathogenicity and clinical relevance: Mucorales are the causative agents of mucormycosis, a rapidly progressive infection that can affect the sinuses, brain, lungs, or skin. Risk factors include diabetes with ketoacidosis, neutropenia, iron overload, corticosteroid use, and organ transplantation. Diagnosis relies on histopathology showing broad, nonseptate hyphae with characteristic branching, supported by culture. Treatment requires urgent surgical debridement, control of underlying conditions, and antifungal therapy, with liposomal amphotericin B as first-line; posaconazole or isavuconazole may be used in some cases.

See also: mucormycosis.