Malassezia pachydermatis isolated from a South American sea lion (Otaria byronia) with dermatitis.

A fungus was isolated from the skin of an Otaria byronia and from the water of the pool in which the animal was kept. It formed creamy colonies with soft texture on Dixon agar and grew well without supplements of long-chain fatty acids. Cells were ovoid to cylindrical in shape, budded from a broad base, and budded and divided at the same location. Thus, the isolate was identified as M. pachydermatis. We compared this very rare isolate from a marine mammal with four strains of M. pachydermatis using the freeze-etching electron-microscopy technique. The cells showed the same characteristic ring-swellings on the protoplasmic membrane on the neck site between the mother and the daughter parts, and the same accumulation of circumvallate bulgings in a small area near the straight sections of spiral grooves as four reference strains. Thus, in terms of morphology and ultrastructure, the isolate could be regarded as a typical M. pachydermatis.