| Abstract: | Scanning and transmission electron microscopy was performed on the various phases of Coccidioides immitis, exposed for different periods of time to the imidazole antifungals miconazole and ketoconazole. The development of spherules into endospores, which takes place in cultures under normal growth conditions, was suppressed in the drug treated cultures. Typical ultrastructural changes were localized at the cell periphery and in the vacuolar system. The drugs did induce changes in mature, resting endospore cultures and in cultures incubated statically at room temperature. Aerobically growing endospores were not susceptible to either drug. The transformation of arthroconidia into mycelium was fully prevented after treatment. Mycelial cells were most susceptible to the antifungals for necrosis was induced in a substantial part of the hyphae after exposure for 24 h. |
