Onychomycosis caused by Trichosporon mucoides

A case of onychomycosis caused by Trichosporon mucoides in a man with diabetes is presented. The infection was characterized by a brown-black pigmentation of the nail plates and subungual hyperkeratosis of the first three toes of both feet. Onychogryphosis was also visible on the third left toe. Direct microscopic examinations revealed wide and septate hyphae and spores. Three cultures on Sabouraud-gentamicin-chloramphenicol 2 agar and chromID Candida agar produced white, creamy, and smooth colonies that were judged to be morphologically typical of T. mucoides. Microscopic examinations of the colonies showed arthroconidia and blastoconidia. The urease test was positive. A sugar assimilation test on yeast nitrogen base agar showed assimilation of galactitol, sorbitol, and arabinitol. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) confirmed the diagnosis of T. mucoides infection. The patient was treated with topical urea and oral itraconazole. Three months later, a mild improvement was observed. The patient was subsequently lost to follow-up.