In vitro antifungal activity of silver nanoparticles against fluconazole-resistant Candida species

Nowadays, current advances in nanotechnology constitute a promising alternative in the development of new antimicrobial agents. Silver nanoparticles (AgNPs) are some very interesting products currently provided by available nanotechnology for control of microbial infection. In the present study, AgNPs were synthesized by eco-friendly method, using cysteine as a reducing agent. Also, antifungal activity against Candida species with resistance to fluconazole was evaluated through determination of Minimum Inhibitory Concentration (MIC50) according to protocol M27-A3 of Clinical and Laboratory Standards Institute (CLSI) and Minimum Fungicide Concentration (MFC). This study was carried out with strains Candida krusei and Candida glabrata. As a result, the formation of spherical nanoparticles was obtained with mean sizes of 19 nm and positive surface charge. Values of MIC50 were 0.1 µg ml(-1) AgNPs for the studied species, and MFC were 0.25 and 0.5 µg ml(-1) for C. glabrata and C. krusei, respectively. The AgNPs synthesized showed cytotoxic effect in 50% of Murine Fibroblast Cells (CC50) at a mean concentrations of 10 µg ml(-1) (100 times higher than MIC50). Consequently, AgNPs could be considered as an alternative potential in the development of new antifungal agents with minimum cytotoxicity in fibroblasts and lethal action on Candida species with resistance to conventional antifungal compounds.