Susceptibility Testing Of Yeasts To The Combination Of Antifungal Drugs In Vitro According To M27-A Method Of NCCLS

Susceptibility testing of yeasts to the combination of antifungal drugs in vitro according to M27-A method of NCCLS Chen Hong(Department of dermatology, Changzheng Hospital affiliated to the Second Military Medical University,Shanghai,200003)Accompanying the elevation of antifungal drug resistance to the fungi year by year ,severe fungal infection increasing under immunosuppressive state and the limited ranges of and troubling side effects of antifungal agents ,the combination of antifungal drugs is one of clinical therapeutic strategies。From the literature we can find some trial conclusions that seems to be self-contradictory。For instance,the same combination of antifungal agents in vitro to various fungi ,sometime to the same fungi,have different interactions。In the clinic cases reports, we can also find that the same combination therapy may have different interactions to vary patients with the same disease。The checkerboard microdilution method was applied to study in vitro interactions of five antifungal drugs according to M27-A method of NCCLS. 28 strains of yeasts were used for combination study。We studied the sterilization effect of AmB plus 5-FC with TEM and FCM。 The correlation between the result of clinical yeasts Susceptibility testing and clinical effect was analysised。Compared with the single agents,there were significant reductions in the geometric mean of the MIC ofthe combinations(P<0.05)。Synergitic and additive interaction were observed obviously in the following three combinations without antagonism:AmB + 5-FC,TBNF+ITRA,TBNF+FCZ。The results of FCM and TEM indicate that the combination of AmB plus 5-FC may enhance the sterilization effect。Although the antagonism can be found in the combinations of other six groups,their main interactions were still additivity,because the average value of their FICIs were all less than 1。The indifferent interaction of AmB + FCZ in vitro to some clinical strains of Cryptococcus neoformans do not influence its clinical effect。...