Virulence and resistance to antifungal therapies of Scopulariopsis species

Abstract

Scopulariopsis is an emerging opportunistic fungus characterized by its high resistance to antifungal therapies. We have developed a murine model of disseminated infection in immunosuppressed animals by intravenous inoculation of Scopulariopsis brevicaulis and Scopulariopsis brumptii, the most clinically relevant species, in order to evaluate their virulence and their responses to conventional antifungal treatments. Survival and tissue burden studies showed that S. brumptii was more virulent than S. brevicaulis. The three drugs tested, liposomal amphotericin B, posaconazole, and voriconazole, prolonged the survival of mice infected with S. brumptii, but none showed efficacy against S. brevicaulis. The different therapies were only able to modestly reduce the fungal burden of infected tissue; however, in general, despite the high serum levels reached, they showed poor efficacy in the treatment of the infection. Unfortunately, the most effective therapy for Scopulariopsis infections remains unresolved.