In vitro activity of clotrimazole for Candida strains isolated from recent patient samples

Minimum inhibitory concentrations (MICs) of clotrimazole (CAS 23593-75-1, Bay 5097, clo) were determined for 142 clinical Candida isolates obtained between 1992 and 1994, including the species Candida albicans (96 strains), Candida glabrata (12 strains), Candida krusei (12 strains), and Candida tropicalis (12 strains). For some of the Candida isolates of all four species, the MICs of amphotericin B and fluconazole were also determined. No MICs of clo of > 4 micrograms/ml were found for all four Candida species, the median of MICs of clo for Candida albicans being 0.03 micrograms/ml with a range from < 0.015 to 4 micrograms/ml. The MICs of clo for Candida albicans were on average 2 log stages below the MICs of fluconazole and 1 log step below the MICs of amphotericin B on the microgram/ml level. Taking account of the present in vitro resistance situation, clo is a highly active antimycotic substance for isolates of all Candida species with human pathogenetic relevance.