Exophialaspecies are capable of causing cutaneous and subcutaneous infections in immunocompromised patients. AnExophialaisolate was cultured from a biopsy specimen of a lesion on the forearm of a patient with myasthenia gravis. The patient also had lesions on the palm and distal aspects of the hand, which were successfully treated with a long-term course of itraconazole. A detailed morphological and molecular characterization of the isolate was undertaken. Phylogenetic analysis of the internal transcribed spacer region and portions of the β-tubulin and translation elongation factor 1-alpha genes indicated that the isolate was a novel species closely related to but genetically distinct from species within theExophiala spiniferaclade; the nameExophiala polymorphasp. nov. is proposed. Morphologically,E. polymorphamost closely resemblesE. xenobioticabut it differs in possessing phialides bearing prominent, wide collarettes, and it does not produce chlamydospores.
Morphological and Molecular Characterization of Exophiala polymorpha sp. nov. Isolated from Sporotrichoid Lymphocutaneous Lesions in a Patient with Myasthenia Gravis