Susceptibility testing of yeasts to combination of amphotericin B and 5-flucytosine in vitro according to M27-A method

This article is to study the interaction between amphotericin B and 5-flucytosine to yeasts in vitro. The checkerboard microdilution method was applied to study in vitro interaction according to M27-A method of NCCLS. Twenty-eight strains of yeasts were used for combination study. Compared with the single agents,there were significant reductions in the geometric mean of the minimal inhibitory concentration of the combination(P0. 01). Synergetic and additive interactions were observed obviously without antagonism. The average value of fractional inhibitory concentration index was 0. 8. Antifun-gal synergy exists between amphotericin B and 5-flucytosine against pathogenic yeasts.