Abstract
The pathogenesis of invasive mycosis caused by filamentous fungi is closely associated with tissue damage resulting from hyphal elongation. The morphological changes that occur during hyphal cell death induced by antifungal drugs, however, have not been extensively investigated. In this study, we cultured Aspergillus fumigatus and Rhizopus oryzae, two representative pathogenic molds, in the presence of isavuconazole and performed dynamic and detailed observations of morphological alterations in their hyphae. We observed cessation of hyphal elongation, degeneration of the cell membrane, and a continuous decrease in the fluidity of the intracellular matrix in both species. As evaluated by propidium iodide positivity, hyphal cell viability was reduced by 96.8% and 100% in A. fumigatus and R. oryzae, respectively. These results suggest that morphological changes in hyphae induced by isavuconazole result in cell death.
