Abstract
The effect of a new azole antimycotic bifonazole on the ultrastructure of hyphal growth of Trichophyton mentagrophytes grown by the slide-culture technique was studied by high resolution scanning electron microscopy. With bifonazole at concentrations ranging from 2 to 500ng/ml, much lower than the MIC value of the drug for this test strain (0.63μg/ml), hyphal growth was significantly inhibited and several ultrastructural changes of the hyphae were produced. These were characterized by: (1) inhibition of hyphal growth showing wavy, curling, bending and twisted hyphae; (2) various abnormal features of growing hyphae and the wrinkled structure; (3) distortion of hyphae (exfoliation of hyphal walls, excretion of amorphous materials with resultant formation of film or seat extending between adjacent hyphae). These ultrastructural changes of the hyphae became more prominent with increasing concentration of the drug. These results strongly suggest that subinhibitory concentrations of bifonazole profoundly affect the normal growth and induce degenerative changes of the hyphae of T. mentagrophytes, probably by affecting some essential metabolism or structure of the cell.
