Studies on Phaeohyphomycosis and Its Causative Agents in China

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 Veronaea botryosa (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 microscope. Besides of these, physiological and other studies were also carried out to aid the correct classification 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 verrucosa was the most dominant species in nature in Shandong, China, followed by Exophiala spinifera and Veronaea botryosa. The pathogenicity of Veronaea botryosa 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.