Apophysomyces

Apophysomyces is a genus of filamentous fungi in the order Mucorales, within the broader group of mucoralean fungi. The genus is characterized by sporangiophores that bear apophyses, a feature reflected in its name. It includes several species, with Apophysomyces variabilis and Apophysomyces trapeziformis among the better studied representatives. These fungi are thermotolerant and commonly found as saprobes in soil and decaying vegetation in tropical and subtropical regions.

Apophysomyces species are notable human pathogens that can cause mucormycosis, a serious invasive fungal infection. Infections are often associated with traumatic injuries, burns, or contaminated wounds and can progress rapidly to involve soft tissue, muscle, and bone. Cutaneous and subcutaneous infections are more frequently reported, but rhino-orbito-cerebral and disseminated forms can occur, particularly in individuals with immune compromise or uncontrolled diabetes. The reported incidence is higher in tropical and subtropical areas, with notable cases in India and surrounding regions.

Identification of Apophysomyces relies on clinical specimens and culture. Microscopic examination reveals broad, nonseptate to sparsely septate hyphae and characteristic sporangiophores ending in sporangia with apophyses. Cultures may produce fluffy, gray-to-tan colonies. Molecular methods and sequencing of ribosomal DNA regions are used for definitive species-level identification.

Treatment requires prompt, combined therapy: aggressive surgical debridement of necrotic tissue and systemic antifungal therapy, typically amphotericin B. Alternatives such as posaconazole or isavuconazole may be considered in certain cases. Early diagnosis and management are associated with improved outcomes, given the potential for rapid progression and high mortality in mucormycosis caused by Apophysomyces.