[Effect of silver nanoparticles on anaerobic bacteria].

OBJECTIVE: The aim was to evaluate the antibacterial effect of silver nanoparticles on anaerobic bacteria. MATERIAL AND METHODS: The microdilution method was used to determine the minimum inhibitory concentrations (MICs) of 28 nm silver nanoparticles, both unstabilized and stabilized by casein, gelatin and polyacrylic acid. The following anaerobic bacteria were tested: Bacteroides fragilis, Bacteroides thetaiotaomicron, Eggerthella lenta, Propionibacterium acnes, Clostridium perfringens, Clostridium difficile and Fusobacterium varium. RESULTS: Unstabilized silver nanoparticles exhibited antibacterial activity at concentrations ranging from 13 to 34 mg/L. A more significant effect with MIC values between 1 and 13 mg/L was shown for silver nanoparticles stabilized by casein. CONCLUSION: Unstabilized silver nanoparticles are active against anaerobic bacteria at concentrations proved to be cytotoxic to eukaryotic cells of human fibroblasts and multicellular organisms. Silver nanoparticles stabilized by casein appear to be more suitable for further research.