Mucormycosis and entomophthoramycosis: a review of the clinical manifestations, diagnosis and treatment

Abstract

The class Zygomycetes is divided into two orders, Mucorales and Entomophthorales. These two orders produce dramatically different infections. Genera from the order Mucorales (Rhizopus, Mucor, Rhizomucor, Absidia, Apophysomyces, Cunninghamella and Saksenaea) cause an angioinvasive infection called mucormycosis. Mucormycosis presents with rhino-orbito-cerebral, pulmonary, disseminated, cutaneous, or gastrointestinal involvement. Immunocompromising states such as haematological malignancy, bone marrow or peripheral blood stem cell transplantation, neutropenia, solid organ transplantation, diabetes mellitus with or without ketoacidosis, corticosteroids, and deferoxamine therapy for iron overload predispose patients to infection. Mucormycosis in immunocompetent hosts is rare, and is often related to trauma. Mortality rates can approach 100% depending on the patient's underlying disease and form of mucormycosis. Early diagnosis, along with treatment of the underlying medical condition, surgery, and an amphotericin B product are needed for a successful outcome. Genera from the order Entomophthorales produce a chronic subcutaneous infection called entomophthoramycosis in immunocompetent patients. This infection occurs in tropical and subtropical climates. The genus Basidiobolus typically produces a chronic subcutaneous infection of the thigh, buttock, and/or trunk. Rarely, it has been reported to involve the gastrointestinal tract. The genus Conidiobolus causes a chronic infection of the nasal submucosa and subcutaneous tissue of the nose and face. This paper will review the clinical manifestations, diagnosis and treatment of mucormycosis and entomophthoramycosis.