In Vitro Antifungal Activity and Mechanism of Ag(3)PW(12)O(40) Composites against Candida Species

Fungal infections pose a serious threat to human health. Polyoxometalates (POMs) are metal–oxygen clusters with potential application in the control of microbial infections. Herein, the Ag(3)PW(12)O(40) composites have been synthesized and verified by Fourier transform infrared (FT-IR) spectrum, transmission electron microscopy (TEM), scanning electron microscope (SEM), elemental analysis, and X-ray diffraction (XRD). The antifungal activities of Ag(3)PW(12)O(40) were screened in 19 Candida species strains through the determination of minimum inhibitory concentration (MIC) by the microdilution checkerboard technique. The minimum inhibitory concentration (MIC(50)) values of Ag(3)PW(12)O(40) are 2~32 μg/mL to the Candida species. The MIC(80) value of Ag(3)PW(12)O(40) to resistant clinical isolates C. albicans HL963 is 8 μg/mL, which is lower than the positive control, fluconazole (FLC). The mechanism against C. albicans HL963 results show that Ag(3)PW(12)O(40) can decrease the ergosterol content. The expressions of ERG1, ERG7, and ERG11, which impact on the synthesis of ergosterol, are all prominently upregulated by Ag(3)PW(12)O(40). It indicates that Ag(3)PW(12)O(40) is a candidate in the development of new antifungal agents.