Antibacterial activity of some saturated polyoxotungstates

Polyoxometalates are important inorganic compounds with a broad range of pharmacological properties, including antiviral, antibacterial, antiprotozoal or antitumoral activities, even that their molecular mechanism of action is poorly understood. Purpose: In this paper we evaluated the antibacterial activity of some saturated polyoxotungstates (POW) compounds, since nowadays, the increasing resistance of bacteria to drugs represents a major health problem. Materials and methods: The antibacterial activity was studied by disk diffusion method as a possible screening method and by successive micro-dilutions method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) have been calculated for each compound by successive dilutions. We also compared the reliability of each testing method for this particular POW evaluation. Results: The best antibacterial activity was expressed by H₄[SiW₁₂O₄₀]*nH₂O and the lowest by Na₃[PW₁₂O₄₀]*nH₂O, but with very good activity on Staphylococcus spp., especially on MRSA. The POW activity occurs only at relatively high concentrations, and it is dependent on bacterial strain, with very good activity on Staphylococcus spp. The most reliable method for assessing the antibacterial effects of POW is micro-dilutions. POWs could be practically applied in hospital decontamination and could have a possible in vivo antibacterial application.