Cutaneous infection caused by Trichosporon dermatis: first case report in China.

Abstract

Objective To report a case of cutaneous infection due to Trichosporon dermatis. Methods Lesional discharge and tissue were obtained and subjected to microscopic examination, fungal culture and histopathology, respectively. The fungal isolate was then identified with DNA sequence analysis, API 20C AUX system, gelatin liquefaction test, thermal tolerance test. Antifungal susceptibility test was also performed for the fungus. Results A 70-year-old male presented with a 9-month history of ulcerated swelling of the right medial malleolus after plant puncture. Direct microscopic examination of lesional discharge showed no fungal elements, but histopathological biopsy revealed hyphae and spores in the dermis. Yellowish white yeast-like colony grew on Sabouraud dextrose agar (SDA). Slide culture showed pseudohyphae, true hyphae, arthroconidia and blastoconidia. The isolate was identified as Candida humicola by API 20C AUX system, but as T. dermatis by DNA sequence analysis. The strain was unable to liquefy gelatin, could grow at 25 ℃ to 40 ℃, and was sensitive to amphotericin B, itraconazole, voriconazole and nystatin. The skin lesion completely subsided after 4-month treatment with oral itraconazole. Conclusions The isolate is identified as T. dermatis according to morphological features and DNA sequence, which is sensitive to itraconazole. Key words: Piedra; Trichosporon; Itraconazole