Structural degeneration of Aspergillus fumigatus after exposure to saperconazole

Saperconazole is a newly synthesized triazole antifungal with potent activity against Aspergillus fumigatus. Exposure of spores inoculated into BHI agar medium to saperconazole doses as low as 35 ng ml-1, resulted in complete suppression of germination (hyphal outgrowth) when treatment started simultaneously with inoculation. Cultures which were grown for 24 or 48 h in the absence of drug and were then exposed to saperconazole showed a block in the development of hyphae, sporophores, vesicles, sterigmata and spores. Moreover, a substantial proportion of the pre-existent hyphae became necrotic during exposure to the drug. The latter was most obvious with the 70 ng ml-1 dose. Although treatment with lower doses yielded severely altered but non-necrotic cells, an abolishment of further outgrowth and differentiation was achieved.