Investigating Synergistic Effect of Silver Nanoparticles and Nisin on Escherichia coli Genome

Introduction: Considering increasing concern about the resistance of microbial infections to antibiotics and nisin peptide reducing effect (AMP) due to resistance growth in bacterial strains; extensive researches were implemented based on nanotechnology. The aim of current research was to investigate synergistic effect of silver nanoparticles conjugated with nisin on genome of Escherichia coli as a gram negative bacteria model. Materials and method: After culturing the bacteria in a Nutrient Broth medium; treatments were performed at concentrations of 50, 75, 100, 125 μg/ml of silver nanoparticles; concentrations of 25, 50, 75, 100 ,150, 200μg/ml of nisin and concentrations of 30, 50, 75 μg/ml of silver nanoparticles conjugated with nisin solution. After reading the optical density at 600 nm of control samples and treated at concentrations of 50 and 75 μg/ml of silver nanoparticles; 50 and 75 μg/ml of nisin, 50 and 75 μg/ml of silver nanoparticles conjugated with nisin, DNA was extracted and RAPD-PCR was used to investigate genomic effect. Analysis of the results of RAPD-PCR was performed by NTSYS-PC software based on Dice coefficient to calculate the similarity matrix and UPGMA. Results: The results showed that the growth inhibitory effect of silver nanoparticles conjugated with nisin was higher than of individual application of nisin and silvernanoparticles and the genomic effect of the above mentioned conjugates was higher and lower than nisin and silver nanoparticles, respectively. Therefore, the mentioned conjugated nanoparticles and nisin had no synergistic effect on the bacterial genome. Discussion and conclusion: these conjugated nanoparticles with nisin can be used as proper and strong antibacterial with the least genomic and mutation effect