Jpn. J. Med. Mycol. Vol. 37, 135-141, 1996 ISSN 0916-4804 Review Studies on Phaeohyphomycosis and Its Causative Agents in China Ruoyu Li, Duanli Wang Department of Dermatology, First Hospital of Beijing Medical University, Beijing, China Abstract Until now, 10 cases of phaeohyphomycosis have been reported in China. Their causative agents were as follows: Exophiala dermatitidis (4 cases), E, spinifera (3), E. jeanselmei (1), Alternaria alternata (1) and Veronaeabotryosa (1). The clinical data will be reviewed in this paper. The pathogenic dematiaceous fungi isolated from the phaeohyphomycosis patients were identified carefully and the conidiogenesis of these organisms was studied by using a scanning electron micro- scope. Besides of these, physiological and other studies were also carried out to aid the correct classi- fication and identification. RAPD-PCR technique was applied to the genomic DNA assay of pathogenic black yeasts' and reveled highly polymorphisms in their genomic fingerprints. The ecological studies were carried out and seven species were isolated from the soil and rotting plant materials. Phialophora aerrucosa was the most dominant species in nature in Shandong, China, followed by Exophiala spinifera and Veronaeabotryosa. The pathogenicity of Yeronaeabotryosa and Exophiala spinifera were studied by using both normal and precompromised mice. The results show that both natural and clinical strains of V. botryosa have potential pathogenicity. E. spinifera is neurotropic and its pathogenicity is specially potential in immunodeficient hosts. Key words: Phaeohyphomycosis, dematiaceous fungi, Exophiala spp., Conidiogenesis, RAPD-PCR mycosis as an opportunistic fungal infection, and Introduction dematiaceous yeast-like cells, pseudohyphae-like Dematiaceous fungi represent a group of fungi elements, hyphae of various shapes or any combi- that bear melanin-like pigment on the wall of nation of these forms could be found in tissue. hyphae and/or spores. Until now, about 57 genus This concept includes many well-established clinical and 101 species have been found to be pathogenic entities such as piedra, keratitis and so on. to human1). They may produce several types of Phaeohyphomycosis has been diagnosed in clinical patterns such as chromoblastomycosis, China only in the last decade. Before that time, phaeohyphomycosis, mycetoma, onychomycosis, the diseases met the same characteristics of the tinea nigra, black piedra, and keratitis2). definition were diagnosed as chromomycosis. To Chromoblastomycosis is the most frequently the present, 10 cases have been reported in the encountered dematiaceous fungal infection in Chinese literature. Their causative agents were as China. Cladosporiumcarrionii is a dominant pathogen follows: Exophiala dermatitidis (4 cases), Exophiala in northeast China in contrast to Fonsecaeapedrosoi spinifera (3), Exophiala jeanselmei (1), Alternaria sp. in southeast China. (1) and Yeronaea botryosa (1)6-8, 10-12,15-17). This The term phaeohyphomycosis was coined in article aims to review the clinical infections and 1974 by Dr. Aiello to cover all the infections of the basic researches on their pathogens in recent cutaneous, subcutaneous and systemic nature 10 years in China. caused by hyphomycetous fungi that develop in the host tissues in the form of dark-walled Clinical reports dematiaceous septate mycelial elements 4) The Exophiala dermatitidis infections: The first clinical types of phaeohyphomycosis include five case was reported by Dr. Bai and Zhang in categories, i.e., superficial, cutaneous, subcutaneous, Dalian, China in 19646). The patient was a 19- systemic and allergic. In 1983, Dr. McGinnis 5) year-old girl with lymphadenopathy and low gave a more boundary definition to phaeohypho- fever for four months. Symptoms of the central 136 真 菌誌 第37巻 第3号 平 成8年 nervous system soon appeared and she died. E. dermatitidis (Fonsecaea dermatitidis) was isolated from the lymphonodes, so that she was diagnosed as having chromomycosis. Including this case, a total of four cases of E. dermatitidis infections was reported. Three of them were systemic and two cases of central nervous system infection were fetal',). E. dermatitidis infection in China also has a broad clinical spectrum as was recently summa- rized by Dr. Matsumodo et a19>. Their review found that the fatality rate of these infections was 48%, which indicates that E. dermatitidis is an important neurotropic dematiaceous hyphomycete since it has a marked tendency to invade the central nervous system. E. spinifera infections: The first case of E. spinifera infection was reported in 1987 in Shandong province by Dr. Dai et al 10). The patient was a 9-year-old boy with extensive grey to black, verrucous lesions covering the whole surface of his body for over a year (Fig. IA). X-rays showed multiple cystic degenerations and pathologic fractures of the bone in the upper and lower extremities. The diagnosis was confirmed by repeated fungal cultures and findings of dematiaceous yeast-like cells or their chains in granulomatous lesions (Fig. 1B). Fungal cultures Fig. 1. The first and fetal case of E. spinifera infection were positive in samples of blood, stool, cutaneous found in Shandong in 1987. A) Crusted, verrucous lesions, and lymph nodes. The boy died three lesions on the patient's face. B) Histological findings years after the development of systemic dissemi- showing granulomatous lesion formation and chain of nation. Another case was a 22-year-old girl who brown colored yeast-like cells in the tissue. came from Zhejiang province, China"). The crusted, verrucous lesions could be found on her face and arm. Granulomatous mass also happened in her nasal cavity. Recurrence occurred soon after the surgical removal of the lesions. All of cases of the three E. spinifera infections were associated with disseminated skin lesions, lymph nodes involvement, and skeletal lesions 12). These findings were similar to those reported elsewhere, espe- cially to the first human infection found in India in 19582,13). Another subcutaneous infection caused by E. spinifera found in El ')Salvador in 198314), showing the same clinical -pictures exhibited by our cases except fungal cells were found within multinucleated giant cells. Fig. 2. Histological findings in the first case of phaeohypho- E. jeanselmei infection: IA 1985, Dr. Yu and mycosis caused by Veronaea botryosa. Long septate hyphae his colleagues 15) reported a 23-year-old female could be found located in the microabscess. farmer with swelling and pain of her left eyelid for one year. She didn't show any response to a 5-month Veronaea botryosa infection: The first case of anti-tuberculosis treatment. Histopathological study human infection caused by Veronaea botryosa was of the intraorbital tissues and the eyeball revealed found in 1990 in Henan Province. A 24-year-old a fungal granuloma. A black yeast was isolated male farmer complained of a 10-year history of from the biopsy materials. It was the fist time to diffuse, black verrucouse nodules and cyst-like use the term 'phaeohyphomycosis' in the Chinese lesions on the back of his left hand, forearm and literatures. both cheeks. Histological examination showed Jpn. J. Med. Mycol. Vol. 37 (No. 3), 1996 137 groups of brown walled, septate hyphae and thick genic dematiaceous fungi are usually difficult to walled spores in the upper dermis (Fig. 2). A identify correctly. Moreover, there is much con- black mold was repeatedly isolated from the tissue troversial on speciation of this group of fungi. culture of the patient. This strain was identified Hence, the pathogenic dematiaceous fungi isolated as Veronaeabotryosa by Dr. Nishimura 16). Since this from phaeohyphomycosis patients were carefully fungus is a new pathogenic dematiaceous species, identified, and the conidiogenesis of these organisms its characteristics have been studied extensively was studied under scanning electron microscope by using different methods. ( SEM) . Besides, physiological tests include Many kinds of dematiaceous fungi can be the thermotolerance, gelatin liquefaction, hydrolysis causes of phaeohyphomycosis. The cases reported of urea and starch, assimilation of KNO3, and re- in China demonstrate that some species belonging quirement of Vitamin B1 were also done. (Table 1) to the genus Exophiala play an important role. Exophiala dermatitidis (Kano) de Hoog, 1977: The main type of the conidial ontogeny of Basic studies E. dermatitidis is annellation. Cladosporium type Genus Exophiala, so called black yeasts, contains occasionally can be found. Most of the isolates can several species which are very similar morphologi- grow at 42C but can not utilize KNO3. These cally in the production of annellidec conidiogenous two characteristics are the key points of distin- cells. It is relatively difficult to make an exact guishing E. dermatitidis from E. jeanselmei. Like speciation normally. The taxonomy and classifica- most of the Exophiala sp., E, dermatitidis strains tion of this group of fungi still have problems. In could not hydrolyze urea, gelatin and starch'. recent years, chemical, serological, and molecular E, jeanselmei (Langeron) McGinnis and biological methods have been used successfully in Padhye, 1977: The conidiogenesis of this species this field. Our studies on the pathogens of is similar to that of all Exophiala species. The phaeohyphomycosis also include physiological, bio- conidiogeneous cells are annellides. The maximum logical, ecological, and pathogenicily ones in growth