The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver, platinum, palladium and copper nanoparticles on Proteus sp. and Klebsiella Sp. isolated from polluted water samples. This study investigated the growth of the two tested bacterial cells in order to observe the action of different concentrations of nanoparticles in addition to the effects on the morphological structure and nucleic acid of these bacteria, It showed AgNPs exhibited a potentially antibacterial effects at most investigated concentrations, While, no detection for the antibacterial activity of PtNPs, PdNPs or CuNPs against both bacterial isolates at all tested concentrations was investigated. The cell morphology of normal and AgNPs-treated bacteria cells was assessed by transmission electron microscopy (TEM), there were investigated a randomly distributed nuclear area and obvious bright electron areas in the center of bacterial cells, it was also noticed that, a rupture in the cell wall of both treated bacterial cells. The effects of silver nanoparticles on genome of bacterial cells revealed that there was a destructive effect on Proteus and Klebsiella genome.

metal nanoparticles, metal nanoparticles, antibacterial activity, action mechanism, Proteus sp., Klebsiella sp.