Chrysosporium tropicum

Colonies are moderately fast growing, flat, white to tan to beige in colour, often with a powdery or granular surface texture. Reverse pigment absent or pale brownish-yellow with age. Hyaline, one-celled (ameroconidia) are produced directly on vegetative hyphae by non-specialized conidiogenous cells. Conidia are typically pyriform to clavate with truncate bases (6 to 7 by 3.5 to 4 um) and are formed either intercalary (arthroconidia), laterally (often on pedicels) or terminally. No macroconidia or hyphal spirals are seen.  RG-2 organism.

Culture of Chrysosporium tropicum.

Chrysosporium tropicum showing typical pyriform to clavate shaped conidia with truncated bases which may be formed either intercalary, laterally or terminally.

Clinical significance:

Species of Chrysosporium are occasionally isolated from skin and nail scrapings, especially from feet, but because they are common soil saprophytes they are usually considered as contaminants. There are about 22 species of Chrysosporium, several are keratinophilic with some also being thermotolerant, and cultures may closely resemble some dermatophytes, especially Trichophyton mentagrophytes, and some strains may also resemble cultures of Histoplasma and Blastomyces.

Mycosis: Hyalohyphomycosis

Further reading:

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

McGinnis, M.R. 1980. Laboratory handbook of medical mycology. Academic Press, London, UK.