In vitro effect of DNA topoisornerase inhibitors on Candida albicans

In this study we investigated the in vitro antifungal activity of 10 DNA topoisomerase inhibitors on the growth of Candida albicans. The EUCAST broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of the compounds for C albicans. In addition, the effect of the inhibitors on the growth mode of C albicans was investigated by light microscopy imaging. Of the 10 DNA topoisomerase inhibitors tested, only the anti-cancer drug aclarubicin displayed antifungal activity with a determinable MIC value of 8.4 mu g/ml (10.3 mu M). Aclarubicin was also active against clinical isolates of C. albicans with MIC values ranging between 0.8 and 7.3 mu g/ml (1-9 mu M). Vitality assays showed that the action of aclarubicin was fungistatic. Four other DNA topoisomerase inhibitors, daunorubicin, doxorubicin, idarubicin and beta-lapachone, affected the morphology of C. albicans. The first three inhibitors encouraged the fungus to grow predominantly in the yeast form, whereas P-lapachone caused hyphal proliferation. The results of this study indicate that some DNA topoisomerase inhibitors effect the growth and morphology of C albicans suggesting a possible role as antifungal agents in the treatment of C. albicans infections.