Susceptibility Testing of 28 Strains of Yeasts to the Combination of Antifungal Drugs in vitro

Objective To study the interaction between antifungal drugs to yeasts in vitro.Methods The in vitro interaction of antifungal drugs was detected with checkerboard microdilution method based on M27-A of NCCLS for28strains of yeasts.Results There was a significant reduction in the geometric means of MICs by the combinations of antifungal drugs to the yeasts compared with the individual agents(P0.05).Synergetic and additive interactions were obviously observed in the following three combinations without antag-onism:amphotericin B+5-flucytosine,terbinafine+itraconazole,terbinafine+fluconazole.Although the an-tagonistic interaction could be found in the combinations of other six groups to some strains of yeasts,the syn-ergetic interactions remained for the majority of yeasts,because the average FICIs(fractional inhibitory con-centration indexes)of all combinations were less than1.Conclusion There is synergetic interaction of the combinations of common antifungal drugs against pathogenic yeasts.