The genus Exophiala contains numerous potential opportunists and pathogens of immunocompetent humans. The most serious pathogens, eventually leading to disseminated, fatal infections are the neurotrope Exophiala dermatitidis, the osteotrope E. spinifera, and the disseminated species E. asiatica. We report a case of subcutaneous phaeohyphomycosis caused by Exophiala equina in a 75-year-old female, who showed subcutaneous abscesses on the both forearms for 8 months. Histopathologically, suppurative granulomatous inflammation and short hyphae & spores were observed. Fungal culture grew out the typical black-gray velvety colonies of Exophiala after 3 weeks. The isolate grew well at 25 _C, but very poorly at 37 _C. No growth could be observed at 40 _C. Initially the species was identified, using colony and microscopic morphology and temperature tolerance test, as E. jeanselmei. However, the results of ITS, BT2 and TEF1 sequencing showed that the correct name is Exophiala equina. This species was initially described from a skin lesion of a horse, but most strains are derived from water, and occasionally from human skin samples. Our report is the first documented human case study of E. equina. The MICs of six of the eight antifungal drugs used in these studies were amphotericin B (1 lg ml-1), fluconazole (>64 lg ml-1), itraconazole (0.063 lg ml-1), voriconazole (2 lg ml-1), Isavuconazole (2 lg ml-1) and posaconazole (0.031 lg ml-1). The two echinocandin agents gave MECs for caspofungin of (>8 lg ml-1) and for micafungin of 0.25 lg ml-1.
- ISHAM 18th (2012)