Effects of amphotericin B and voriconazole on ultrastructure of a clinical isolate of Penicillium marneffei / 中华皮肤科杂志

ABSTRACT

Objective To observe ultrastructural changes in a clinical isolate of Penicillium marneffei(PM) before and after treatment with amphotericin B or voriconazole by using scanning electron microscopy (SEM)and transmission electron microscopy (TEM). Methods A microdilution method was performed to determine the minimum inhibitory concentration (MIC)of amphotericin B and voriconazole against a clinical isolate of PM. Then, the PM isolate was treated with amphotericin B or voriconazole at their MICs and 10-fold MICs for 24, 48 and 72 hours. The ultrastructural changes in this isolate before and after the treatment were observed by using SEM and TEM. Results After the treatment with amphotericin B, SEM showed that the conidia or yeast cells of the PM isolate were gradually damaged, and their outer layers experienced detachment, shrinkage, breakage and adhesion with the increase in treatment duration and concentrations of amphotericin B; TEM also showed degenerated mitochondria, broken nuclei and cell walls, and shrunken cytoplasmic membrane with disappearance of cytoplasmic organelles. Similarly, the damage, shrinkage, shriveling and collapse of PM cells were seen by using SEM, and TEM showed many high-density electron-dense granules in cytoplasm, degeneration of mitochondria, roughening of cell wall surface, damage and shrinkage of cytoplasmic membrane, and disappearance of cytoplasmic organelles after voriconazole treatment. Conclusions Amphotericin B and voriconazole both had a strong antifungal effect on PM, and could induce evident ultrastructural changes, which were positively associated with treatment duration and concentrations. Moreover, amphotericin B caused more severe damage to PM compared with voriconazole.