Abstract Regarding the bacterial resistance of current antibiotics, many studies have been conducted to evaluate the antimicrobial properties of metal nanoparticles such as silver and copper oxide. This study was carried out to compare the effects of these nanoparticles on the genome of Escherichia coli strain O157: H7 as a model for gram-negative bacteria. For this purpose, the bacteria were first treated by 30 and 60 μg/ml the nanoparticles and the growth of bacteria was controlled at certain time intervals by spectrophotometry to evaluate the antimicrobial activity. Then the DNA was extracted to investigate the effects of the nanoparticles on the genomes 4 hours after treatment using RAPD-PCR. The bands obtained from electrophoresis of PCR products on agarose gel 2% were analyzed. The results of the study revealed that silver and copper oxide nanoparticles not only inhibit the growth of bacteria, but also change the genomic DNA sequences and cause genetic differences between control and treated samples. Metal nanoparticles are antibacterial compounds, and copper oxide was more effective than silver on E. coli genome as a model for gram-negative bacteria.
