Rhizopus microsporus var. microsporus

Rhizopus microsporus var. microsporus is a rare cause of human infection (Kerr et al. 1988, Kwon-Chung and Bennett, 1992). Colonies are pale brownish-grey producing simple rhizoids. Sporangiophores are brownish, up to 400 µm high and 10 µm wide, but most are smaller and are produced in pairs. Sporangia are greyish-black, spherical, up to 80 µm in diameter.   Columellae are subglobose to globose to conical. Sporangiospores are angular to broadly ellipsoidal to lemon-shaped, quite equal in size, up to 5-6 µm in diameter and are distinctly striate. Zygospores, formed by crosses of compatible mating strains, are dark red–brown, spherical, up to 100 µm in diameter, with stellate projections and unequal suspensor cells. There is good growth at 45OC, with a maximum of 46–48OC. RG-2 organism.

Mycosis: Zygomycosis

Further reading:

Domsch, K.H., W. Gams, and T.H. Anderson. 1980. Compendium of soil fungi. Volume 1. Academic Press, London, UK.

Ellis, D.H. 1997. Zygomycetes. Chapter 16 In Topley and Wilson's Microbiology and Microbial Infections. 9th edition Edward Arnold London pp247-277.