Phaeohyphomycosis due to Exophiala xenobiotica as a cause of fungal arthritis in an HIV-infected patient

Black yeasts including Exophiala species are increasingly recognized as agents of human disease. In recent years, progress in molecular phylogeny and taxonomy of the genus Exophiala has led to the description of numerous novel species. The 'classical' but highly variable species Exophiala jeanselmei was split into a number of morphological siblings, which, however, were phylogenetically and clinically remote from each other. E. jeanselmei was restricted to an uncommon species causing subcutaneous infections. Hence only limited information is available on the segregants, among which is E. xenobiotica. We describe a case of an HIV-patient presenting with fungal arthritis and subcutaneous nodules caused by the latter species, which was identified by means of phenotypic and molecular methods.