The antimicrobial activity of zinc oxide nanoparticles on Enterobacter aerogenes was examined. A set of different concentrations of nanoparticles at 50, 75,100 & 125 µg/ml were tested on gram negative Enterobacter sp. for their concentration dependent antimicrobial effects. A number of other bacteria including E. coli & B. subtilus were also evaluated against zinc oxide nanoparticles suspension to check the bacterial growth.
The antimicrobial activity was examined by drawing growth curves using spectrophotometer assisted absorption observations. The zinc oxide nanoparticles adsorption on bacterium surface was visualized by scanning and transmission electron microscopies. The antimicrobial activity was further confirmed by disc diffusion method. The increased concentrations of zinc oxide nanoparticles effectively checked the bacteria growth and increased the diameter of inhibition zone in the experiment.
In presence of zinc oxide nanoparticles, Enterobacter sp. growth was significantly reduced while the zinc oxide powder showed lower levels of antimicrobial activity when compared at same dose levels of 50, 75, 100 & 125 µg/ml. Further studies on a mixture of lower levels of antimicrobial drugs and zinc oxide nanoparticle formulation are in progress with a view to effectively curtail the comparatively large dose regimen of the anti-microbial drugs.