Preliminary Study On Synergy Of Tetrandrine On Fluconazole Against Bioflim Of Candida Albicans

1 ObjectiveTo investigate the synergistic effect of tetrandrine(TET) on fluconazole(FLC) to biofilm of Candida albicans(C. albicans), providing experimental basis for the prevention and treatment of biofilm related infection.2 MethodsA series of 16 isolates of C. albicans which are differently sensitive to FLC have been investigated. The maximum non-cytotoxic concentration of TET on yeast form of these isolates and the minimum inhibitory concentration(MIC) of FLC alone and combination with TET were determined by the CLSI proposed M27-A microdilution method. Paired-sample t-test was adopted to test the results.The biofilm of C. albicans was built, and the sessile minimum inhibitory concentration(SMIC) of FLC alone and combination with TET on each stage of biofilm were determined by the XTT reduction assay. Paired-sample t-test was adopted to test the results. The MIC of FLC alone and combination with TET on re-suspended C. albicans biofilm were determined by the CLSI proposed M27-A microdilution method. Paired-sample t-test was adopted to test the results.3 ResultsThe maximum concentration at which TET had no cytotoxic effect to the yeast form C. albicans was 30μg/mL. The MIC of FLC alone to the yeast form C. albicans(1×103CFU/mL) were 0.25-64μg/mL and 0.125-16μg/mL when combined with TET. The result had statistical significance(P=0.003). The MIC of FLC alone and combined with TET were> 64μg/mL in the cell counts of 1×106 CFU/mL.In the 0th h of C. albicans biofilm forming, the SMIC50 of FLC were 0.25-64μg/mL and 0.125-16μg/mL when combined with TET. The result was statistically significant(P=0.002). In the 4th h of C. albicans biofilm forming, the SMIC50 of FLC were 8-256μg/mL and 1-64μg/mL when combined with TET. It was statistically different (P=0.000). In the 24th h and 48th h, the SMIC50 of FLC alone and combination with TET were> 1024μg/mL respectively.The MIC of FLC alone to the re-suspended C. albicans biofilm(1×103 CFU/mL) were 0.25-64μg/mL and 0.125-16μg/mL when combined with TET. The result had statistical significance(P=0.003). The MIC of FLC alone and combination with TET were>64μg/mL respectively in the cells counts of 1×106 CFU/mL.4 Conclusions4.1 There is synergistic effect of tetrandrine to fluconazle against the early stage of C. albicans biofilm formation, without any synergistic effect in the medium stage and maturity stage.4.2 Tetrandrine can inhance the inhibitory effect of fluconazole against formation of C. albicans biofilm.4.3 There is synergistic effect of tetrandrine to fluconazle agains the re-suspended thalli of C. albicans biofilm(1×103CFU/mL).4.4 Based on the different drug resistance mechanisms on each stage bioflim formation of C. albicans, the results above demonstrate that synergistic effect of tetrandrine to fluconazle agains C. albicans biofilm is related with efflux pumps directly.