1Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA; 2Infectious Diseases, Department of Medicine, School of Medicine, University of Wisconsin, Madison, WI, USA; 3University of Alberta Microfungus Collection and Herbarium, Devonian Botanic Garden, Edmonton, AB, Canada
Clinicians are increasingly confronted with sick reptiles in need of safe and effective antifungal drugs. There few studies of pharmacokinetics of antifungal drugs have involved even fewer reptile species, and none addresses efficacy. There are currently no guidelines for selection of appropriate antifungal agents in reptiles because there are no data on efficacy of drugs against many of the fungi pathogenic to reptiles. The susceptibility of 26 fungal isolates originating from reptiles to various antifungal drugs was determined using NCCLS protocols standardized testing methods for filamentous fungi. Preliminary analysis of data indicates that MICs obtained for amphotericin B, fluconazole, terbinafine, and voriconazole were similar for the teleomorphic Nannizziopsis vriesii isolate and all 16 Chrysosporium anamorphs of Nannizziopsis vriesii (CANV) isolates, but that MICs for itraconazole were slightly higher for CANV isolates from bearded dragons. Low MICs for amphotericin B, terbinafine, itraconazole and voriconazole (in isolates other than bearded dragon) suggest CANV isolates are sensitive to these compounds. Fluconazole MICs were high for all fungi except Trichosporon asahii. Paecilomyces lilacinus was resistant to fluconazole and to amphotericin B, but sensitive to terbinafine and voriconazole. Amphotericin B MICs were high for Fusarium solani and F. verticillioides isolates, and terbinafine and voriconazole MICs were also high for F. solani. In vitro sensitivity testing of reptile isolates suggests that itraconazole, voriconazole, and terbinafine are more potent than amphotericin B and fluconazole. Considering the pharmacokinetics of these drugs, itraconazole, voriconazole, and terbinafine would be expected to be the best options for treatment of CANV, Paecilomyces lilacinus, Trichosporon asahii, and Fusarium spp. mycoses in reptiles.
The authors thank Kerry O’Donnell for supply of Fusarium isolates. This study was funded by the Association of Reptilian and Amphibian Veterinarians.