Malbranchea species are soil fungi of worldwide distribution which microscopically may resemble Coccidioides immitis/posadasii. Note: Culture identification by exoantigen test or ITS sequencing is the method of choice for identification of C. immitis/posadasii.
Colonies are white to sulphur-yellow to ochre-brown in colour, suede-like in texture, with a reddish-brown reverse, and often a reddish diffusible pigment. Microscopic morphology shows typical hyaline, one-celled, cylindrical, truncate, alternate arthroconidia produced in tightly coiled, terminal fertile branches of the hyphae. Arthroconidia are released by lysis of the disjunctor cells. These arthroconidia may be perceived as a yellow dust when released at maturity.
Hyphomycete producing alternate arthroconidia with disjunctor cells.
Cooney and Emerson (1964), Sigler and Carmichael (1976), McGinnis (1980), Rippon (1988), de Hoog et al. (2000, 2015).