Antibiotic treatment to control majority of infections was slowly becoming a problematic as most of the antibacterial studies were designed for the free planktonic forms. But when it comes to biofilm studies, the antibiotic usage has been restricted due to the formation of thick wall in the biofilms. So for a proper understanding of the physiological mechanism on antibacterial activities, nanoparticles have been used. The food borne pathogens like Salmonella typhii and Salmonella paratyphii have been used in our study to investigate the effect of silver nanoparticles on them. Our results suggest that there was a significant increase in the percent of inhibition among the two species with the increasing concentration of the nanoparticles. But there was no such effect found between the species. It was found from the results that the rate of percent inhibition was concentration dependent. The inhibition of biofilm formation in Salmonella typhii was found to be 0.74± 0.13, 0.69± 0.3, 0.61± 0.23, 0.5± 0.13, 0.42± 0.38, 0.28± 0.29 and 0.17± 0.53 for control, 50μg/ml, 100μg/ml, 200μg/ml, 300μg/ml, 400μg/ml and 500μg/ml respectively. The effect of nanoparticles on the biofilm formation and primary adherence assay was found to be concentration dependent.
