Van Tieghem 1875, Scholer 1970

Macroscopic morphology

Colonies on potato dextrose agar at 25°C are woolly and initially white, quickly becoming pale gray and then developing small gray dots in the mycelium which are mature sporangia. Good growth at 46°C; no growth at 50 °C.

Microscopic morphology

Hyphae are hyaline, broad (5-15 µm), ribbon-like, irregularly branched, and aseptate to sparsely septate. Sporangiophores and rhizoids are borne from creeping aerial hyphae known as stolons. Sporangiophores (up to 400 µm in length but usually shorter) are mostly unbranched, brown to dark brown, are produced singly or in pairs, and bear small grayish-black sporangia (up to 80 µm in diameter) with subglobose to conical columellae. Sporangiospores are angular to broadly ellipsoid, up to 6.5 -7.5 µm, and distinctly striate. Rhizoids are simple, hyaline to pale brown, and occur at the junctions of the stolons and sporangiophores (nodal). The species is heterothallic, requiring compatible mating strains for the production of zygospores [2202], [2049], [531], [2408].

Special notes

There are three documented human infections owing to this organism. Kerr et al [1183] reported an infection in the limb of a patient who was receiving hemodialysis and who survived with aggressive treatment and amputation. It has also been isolated form a lung biopsy specimen in a leukemic patient with pneumonia [1274], and as an agent of zygomycosis in the leg of a diabetic requiring amputation [2408].

FTL* in vitro susceptibility data

0.5 µg/ml=1 4.0 µg/ml=1

* Fungus Testing Laboratory unpublished data (NCCLS M38-A)