Abstract

We evaluated the in vitro activity of posaconazole and amphotericin B against several clinical strains of the mucoralean fungus Apophysomyces variabilis, and their efficacy in a murine model of disseminated infection caused by that fungus. The in vitro susceptibility of seven strains of A. variabilis to posaconazole and amphotericin B was determined by using a broth microdilution method. The in vivo efficacy of both drugs, posaconazole at 20 mg/kg twice daily orally by gavage and amphotericin B at 0.8 mg/kg once daily intravenously, was evaluated against six of the strains previously tested in vitro using immunocompetent mice. In general, MICs of both drugs were within the range of susceptibility or intermediate susceptibility. Posaconazole and amphotericin B were able to significantly reduce the percentages of positive cultures in the affected tissues. However, in general, posaconazole significantly improved survival (median, 23 days; range, 730 days) compared with untreated controls (median, 6 days; range, 47 days) and, in some cases, with respect to the animals treated with amphotericin B (median, 15 days; range, 530 days). Our results demonstrate the efficacy of posaconazole in the treatment of a disseminated murine infection caused by A. variabilis. However, further clinical studies are required to ascertain the potential use in human infections caused by this fungus.