Description:
The Mucorales, formerly known as Zygomycetes, have large ribbon-like aseptate hyphae (though occasional septa occur). They have sporangia (sac-like structures) that produce yellow or brown spores. The sporangia are supported by sporangiophores, which are connected by stolons. The production of these spores within sporangia is unique to the Mucorales (Zygomycetes). Rhizoids arise at contact points in some species (e.g., Rhizopus spp.). They are also fairly rapid growers, which is not unique to this group, since Aspergullus spp. and others can grow fairly rapidly. The colonies are often grey.
Representative organisms:
Rhizopus (most common), Mucor, Cokeromyces, Rhizomucor, Saksenaea, Apophysomyces, and Cunninghamella spp. will be discussed here. Cunninghamella spp. and Syncephalastrum spp. are also occasionally found, mainly as laboratory contaminants.
Epidemiology and disease:
Infections by these organisms are important in immunocompromised people, especially those with Diabetes Mellitus. These molds are normally found in decaying matter and stale bread (especially Mucor spp.). They are acquired by inhalation or ingestion and occasionally by scrapes on the skin. They can cause various symptoms, from thrombosis to nasal sinuses and brain infections and, less commonly, the lungs, GI tract, skin, and subcutaneous tissues.
Diagnosis and Identification:
Direct samples are best cultured on potato dextrose, 2% malt, and acidic agars. The mycelium grows within 24–48 hours at 27–30° C. It grows rapidly and produces fluffy white/grey or brown hyphae.
