Ampicillin-augmented Silver Nanoparticles for Synergistic Antimicrobial Response: A Promising Therapeutic Approach.

Abstract

Globally, scientists are working to find more efficient antimicrobial drugs to treat microbial infections and kill drug-resistant bacteria. Despite the availability of numerous antimicrobial drugs, bacterial infections still pose a serious threat to global health. A constant decline in the effectiveness of antibiotics owing to their repeated exposure as well as a short-lasting antimicrobial activity led to the demand for developing novel therapeutic agents capable of controlling microbial infections. In this study, we report the antimicrobial activity of chemically synthesized silver nanoparticles (cAgNPs) augmented with ampicillin (amp) in order to increase antimicrobial response against Escherichia coli (gram -ve), Staphylococcus aureus (gram +ve) and Streptococcus mutans (gram +ve). Nanostructure, colloidal stability, morphology and size of cAgNPs before and after functionalization were explored by UV-vis spectroscopy, FT-IR, zeta potential and TEM. The formation and functionalization of cAgNPs were confirmed from UV-vis spectroscopy and FT-IR patterns. From TEM, the average sizes of cAgNPs and cAgNP-amp were found to be 13 and 7.8 nm, respectively, and change in colloidal stability after augmentation was confirmed from zeta potential values. The antimicrobial efficacies of cAgNP-amp and cAgNPs against E. coli S. aureus and S. mutans were studied by determining Minimum Inhibitory Concentrations (MICs), zone of inhibition, assessment of viable and non-viable bacterial cells and quantitative assessment of biofilm. Our results revealed cAgNP-amp to be highly bactericidal compared to cAgNPs or amp alone. The nano-toxicity studies indicated cAgNP-amp to be less toxic compared to cAgNPs alone. This study manifested that cAgNPs show synergistic antimicrobial effects when they get functionalized with amp suggesting their application in curing long-term bacterial infections.