Abstract:

To report a case of cutaneous and subcutaneous coinfection caused by Lichtheimia corymbifera and Candida parapsilosis. A 67-year-old female peasant consulted about proliferative granuloma developing on her left forearm after topical application of a Chinese herbal drug and splint fixation for the treatment of suspected fracture of the wrist. Direct microscopic examination showed gram positive budding yeast cells in lesion secretions. Pathological study with periodic acid-Schiff （PAS） and gormori methenamine silver （GMS） staining revealed broad non-separate hyphae in the corneum and dermis. Fungal culture of lesional tissue at 35℃ grew both mould and yeast. The mould was identified as Lichtheimia corymbifera based on morphological findings and sequences of the internal transcribed space （ITS） 1-4 regions. Thermal tolerance study revealed that the isolate grew fast at 37℃ but slowly at 40℃. Under a scanning electron microscope, the acrogenous sporangia were pear-shaped with conical sporangiophores originating from the top of stolon, which were among but not opposite to the rhizoids. The yeast was identified as Candida parapsilosis by Chromagar test and D1/D2 region sequencing. As antimicrobial susceptibility test indicated, the Lichtheimia corymbifera isolate was most sensitive to terbinafine and itraconazole. The proteolytic activity of Lichtheimia corymbifera was higher than that of Candida parapsilosis. The granuloma completely subsided after surgical resection and 6-week treatment with oral itraconazole 200 mg twice a day. No recurrence was observed during a 4-year follow-up.

Key words: Cutaneous and Subcutaneous Infection