Comparative activity in different media of ketoconazole, miconazole and amphotericin B against Candida lusitaniae and sucrose-negative Candida tropicalis.

Abstract

This study evaluates the susceptibility of sucrose-negative Candida tropicalis and Candida lusitaniae strains to amphotericin B (AMB), miconazole (MCZ) and ketoconazole (KTZ). The susceptibility tests were carried out in different media: Antibiotic Medium 3 (AM-3m) and Earle Minimum Essential Medium (E-MEM) for AMB: Yeast Nitrogen Base (YNB) and E-MEM for imidazole compounds. The minimal fungicidal concentrations (MFCs) of AMB were slightly higher than minimal inhibitory concentration (MICs) except against Candida lusitaniae strains; whereas the MFCs of MCZ and KTZ were higher than the MICs by almost two-fold for all strains tested. AMB was more efficacious against sucrose-negative Candida tropicalis and the MICs were very definite; on the contrary, the MICs with KTZ were difficult to read. The MICs of AMB in E-MEM were essentially the same as those in AM-3m; whereas for KTZ and MCZ determined in YNB the MICs were generally higher than those obtained in E-MEM.