(described by Saccardo in 1882)
Taxonomic Classification
Kingdom: Fungi
Phylum: Ascomycota
Class: Euascomycetes
Order: Onygenales
Family: Gymnoascaceae
Genus: Malbranchea
Description and Natural Habitats
Malbranchea is a mould isolated from soil, decaying vegetation, and animal dung. It is commonly isolated as a contaminant. Malbranchea has telemorphs classified in genera Auxarthron, Uncinocarpus, and Myxotrichum.
Species
The most commonly known species of Malbranchea are Malbranchea pulchella and Malbranchea sclerotica. See the summary of synonyms and telemorph-anamorph relations for the Malbranchea spp.
Pathogenicity and Clinical Significance
Malbranchea has been isolated from a case with sinusitis [215]. No other infection associated with Malbranchea has been reported so far.
Macroscopic Features
The colonies of Malbranchea grow moderately rapidly at 25°C. They are raised or flat, with or without furrows, and powdery, woolly, or cottony in texture. The color of the colony may be white, orange, buff, tan, brown, or dark golden [531, 2202].
Microscopic Features
Malbranchea produces hyphae and arthroconidia. Sclerotia may be formed. Conidiophores are absent. Hyphae are septate and hyaline. Arthroconidia are one-celled, cylindrical, straight or curved, truncate, hyaline to greenish-yellow and not wider in diameter than the hypha that bears them. Arthroconidia form straight fertile areas on the primary hyphae. Arthroconidia alternate with disjunctor (sterile and empty) cells and are released by the lysis or fracture of the disjunctor cells. Liberated arthroconidia bear annular frill [531, 2202].
Compare to
Due to the existence of arthroconidia and the disjunctor cells, the two genera, Malbranchea and Coccidioides are similar microscopically. However, Malbranchea differs from Coccidioides immitis by its failure to produce spherules containing endospores, and by not reacting with Coccidiodies immitis specific reagents in the exoantigen test or the DNA test probe. In addition, the fertile hyphae of Malbranchea are curved while those of Coccidioides are straight [531, 2202].
Laboratory Precautions
Due to the extreme similarity of Malbranchea and Coccidioides immitis, isolates should be studied in a biological safety cabinet until they are identified.
Susceptibility
No data are available.