Experimental Infection of Mice with as a Model for Human Phaeohyphomycosis.

is a ubiquitous, dematiaceous mold capable of causing cutaneous and subcutaneous lesions in humans. In the last decade, has been associated with emergent systemic fungal infections in aquatic animals, including cultured sturgeon ( spp.), captive amphibians, and wild reptiles. Recently, repetitive extragenic palindromic PCR (rep-PCR) fingerprinting has demonstrated intraspecific variability among isolates from different clinically affected hosts and geographic regions. However, little is known regarding the pathogenic potential of the different genetic clades, and no mammalian model currently exists to investigate phaeohyphomycosis. In this study, we inoculated immunocompetent heterozygotic () and immunodeficient homozygotic () Hsd:Athymic Nude-Fox1 mice subcutaneously or through orogastric gavage with 1 of 3 representative strains that had been recovered from white sturgeon (), green sea turtle (), and human hosts and typed by using rep-PCR analysis. Daily mortality and morbidity were recorded, and dissemination of the fungus was investigated through culture of splenic samples and histologic analysis of the injection site, regional lymph nodes, salivary gland, spleen, liver, mesenteric lymph node, and gastrointestinal tract. No differences in survival, fungal burden, or dissemination were observed between fungal strains, routes of inoculation, or host immune status. Fungal infection was observed after subcutaneous inoculation only, was localized to the inoculation site, and was identified in both and mice. Fungal strain variability was not associated with virulence in a murine model of infection, and this novel mouse model of phaeohyphomycosis recapitulates the human clinical condition.