In vitro activity of terbinafine against medically important non-dermatophyte species of filamentous fungi

Objectives: The activity in vitro of terbinafine against 442 clinical isolates of several species of filamentous fungi was analysed. Methods: A broth microdilution test was carried out following the National Committee for Clinical Laboratory Standards reference method, with modifications described previously. Results: The geometric mean (GM) of MICs of terbinafine for non-Aspergillus fumigatus species was 0.24 mg/L whereas the GM for A. fumigatus rose as far as 2.92 mg/L. Terbinafine showed a very strong activity in vitro against Penicillium spp., Paecilomyces spp., Trichoderma spp., Acremonium spp. and Arthrographis spp. with GMs <1 mg/L. However, some species such as Scedosporium spp., Fusarium spp., Scopulariopsis brevicaulis, and most of Mucorales exhibited high MICs of the allylamine with GMs greater than or equal to 4 mg/L. Conclusions: Overall, the GM of MICs of terbinafine was 1.57 mg/L, but significant differences in susceptibilities were seen between genera and species.