Susceptibility of clinical isolates of yeasts to anti-fungal agents.

The antimicrobial activity of amphotericin B, 5-fluorocytosine, nystatin, clotrimazole and miconazole were compared in vitro against 244 strains of yeasts that had been isolated from clinical specimens. The yeasts used in this study included 20 species of Candida, Cryptococcus, Saccharomyces Geotrichum, Rhodotorula, Torulopsis and Trichosporon. The majority of the strains (78%) had an MIC of less than or equal to 0.5 microgram/ml for amphotericin B, 81% an MIC of less than or equal to 1 microgram/ml for 5-fluorocytosine, 99% less than or equal to 8 micrograms/ml for nystatin, 91%, less than or equal to 8.0 micrograms/ml for clotrimazole and 98% had an MIC of less than or equal to 4.0 for miconazole. Of the anti-fungal agents tested, 5-fluorocytosine and nystatin were found to have the greatest antifungal activity.