Sensitivity of yeasts to amphotericin B and 5-fluorocytosine.

One hundred and forty-four clinical yeast isolates were tested for antifungal susceptibility to Amphotericin B (AMB) and 5-Fluorocytosine (5FC). 61% (88 of 144) of the total yeast isolates were C. albicans. Yeasts were most frequently isolated from high vaginal swabs. High vaginal swabs constituted 64% (92 of 144) of the total number of specimens. Antifungal susceptibility testing of yeasts was conducted by employing an agar dilution technique. 76% (67 of 88) of C. albicans demonstrated MIC values of less than or equal to 1.0 ug/ml to 5FC. All yeasts tested against AMB demonstrated MICs of less than or equal to 0.25 ug/ml. Resistance to 5FC and AMB was defined as any isolate demonstrating an MIC of greater than 16 ug/ml and MIC greater than or equal to 2 ug/ml respectively. Based on this definition approximately 6% of total yeasts and 8% of C. albicans were resistant to 5FC. All yeasts tested were sensitive to AMB.