1. Gross morphology of Rhizopus,Mucor, and Absidia isolates in culture.
Gross morphology of Rhizopus,Mucor, and Absidia isolates in culture. (A)Rhizopus gross morphology on SABHI medium.Rhizopus spp. typically produce a very high, fibrous colony that rapidly fills the entire petri dish. This isolate has expanded to the lid (known as a “lid lifter”). It has produced abundant pigmented sporangia, which are seen as the dark areas peppering the otherwise pale mycelium. This morphology is characteristic of theRhizopus spp. (B) Low-growing Mucor variant gross morphology on SABHI medium. Mucor spp. will show variation from culture to culture. This particular isolate has produced a low-growing, fibrous colony morphology that readily demonstrates the “woolly” or floccose growth characteristic of theMucoraceae. Pigmentation is also variable, both within and among the Mucor spp. Increased pigmentation is generally reflective of areas of the mycelium that are rich in sporangia. Depending on the individual isolate, Mucor may be extremely floccose or low growing and may range from pure white to shades of gray or brown. (C) Absidia corymbifera gross colony morphology on SABHI medium. A. corymbifera produces a light-colored mycelium, generally cream or gray. The peppered appearance seen in theRhizopus spp. is lacking despite the production of abundant sporangia. The mycelium of this isolate is firmly plastered to the lid of the petri dish, consistent with the lid-lifting properly of this fungus. (D) A. corymbifera, reverse side of the culture plate shown in panel C. The Mucoraceae are hyaline molds that produce a pale reverse in culture on standard media such as SABHI agar. Although some isolates such as Rhizopus spp. may have lightly pigmented hyphal elements, this is generally reflected as a pale yellow or brown reverse and not the darkly pigmented reverse of the dematiaceous fungi.
Julie A. Ribes et al. Clin. Microbiol. Rev. 2000; doi: /CMR