Taj-Aldeen Saad J, Al-Ansari Hamda I, Boekhout Teun, Theelen Bart
Department of Laboratory Medicine and Pathology, Division of Microbiology, Hamad Medical Corporation, Doha, Qatar.
Med Mycol. 2004 Feb;42(1):87-92. doi: 10.1080/1369378032000141453.
White piedra is a rare fungal infection of the hair shaft characterized by small, firm, irregular white-brown nodules. The infection is caused by basidiomycetous yeasts in the genus Trichosporon. We report a case of a 28-year-old female patient who acquired the infection in Qatar. In this case, the scalp was the only site affected, but infection at that site was extensive. The hair had a Saccharomyces-like yeast odor and appeared to be beaded, with light-brown nodules of varying sizes up to 2 mm long. Trichosporon sp. accompanied by Candida parapsilosis grew out along hair shafts planted in primary isolation media. Molecular identification of the Trichosporon carried out by analyzing the 26S ribosomal gene gave a 100% match with Trichosporon inkin, a major cause of pubic white piedra. The patient was treated with daily applications of ketoconazole shampoo followed by econazole shampoo and cream, and was considered clinically and mycologically cured after 2 months. Novel findings in the present case are the first identification of T. inkin as an agent of scalp white piedra, and the heavy outgrowth of C. parapsilosis from the concretions, although in the latter case it is not clear if the co-occurring yeast was etiologically contributory to the pathogenesis of the white piedra.
白癣是一种罕见的毛干真菌感染,其特征为小的、坚硬的、不规则的白棕色结节。该感染由毛孢子菌属的担子菌酵母引起。我们报告一例28岁女性患者,她在卡塔尔感染了此病。在该病例中,头皮是唯一受影响的部位,但该部位的感染范围广泛。头发有类似酵母菌的气味,看起来呈串珠状,有大小不一的浅棕色结节,最长达2毫米。在接种于初次分离培养基的毛干上,毛孢子菌属与近平滑念珠菌一同生长出来。通过分析26S核糖体基因对毛孢子菌进行分子鉴定,结果显示与引起阴部白癣的主要病原菌英克毛孢子菌100%匹配。患者接受了每日使用酮康唑洗发水,随后使用益康唑洗发水和乳膏的治疗,2个月后临床和真菌学检查均认为已治愈。本病例中的新发现是首次鉴定出英克毛孢子菌为头皮白癣的病原菌,并从结石中大量培养出近平滑念珠菌;不过在后一种情况下尚不清楚同时存在的酵母菌是否在病因上对白癣发病机制有促成作用。