Phialophora richardsiae

Colonies grow rapidly, and are powdery to woolly or tufted, greyish-brown with a grey-brown to olivaceous-black reverse. Two conidial types are produced; (1) hyaline conidia which are allantoid or cylindrical, 3-6 x 1.5-2.5 μm in size, formed on inconspicuous, peg-like phialides on thin-walled hyphae; and (2) brown, thick-walled conidia which are spherical to sub-spherical, 2.5-3.5 x 2-3 μm, formed on dark brown, slender, tapering phialides with flaring collarettes. RG-2 organism.

Phialides of P. richardsiae producing 2 types of conidia. (1) hyaline conidia, formed on inconspicuous, peg-like phialides on thin-walled hyphae; and (2) brown, thick-walled conidia formed on dark brown, slender, tapering phialides with flaring collarettes.

MIC data is limited.  Antifungal susceptibility testing of individual strains is recommended.

Clinical significance:

Phialophora richardsiae is a soft rot fungus of wood and is an uncommon cause of human infection. However, cases of subcutaneous phaeohyphomycosis have been reported.

Mycosis: Phaeohyphomycosis

Further reading:

De Hoog G.S. and J Guarro. 1995. Atlas of clinical fungi. Centraalbureau voor Schimmelcultures, Baarn and Delft, The Netherlands.

Kwon-Chung, K.J. and J.E. Bennett. 1992. Medical Mycology. Lea & Febiger, Philadelphia and London.