Role of Green Silver Nanoparticles in the Inhibition of Listeria monocytogenes and Escherichia coli

Background: The quandary of antimicrobial resistance is rapidly becoming a cause for global concern. Meanwhile, green biological synthesis of silver nanoparticles is being extensively studied for their antibacterial properties. However, in the dearth of appropriate and substantial evidence, the development of Green Silver Nanoparticles (GSNPs) as the antibacterial drug is impeded. Objective: The present study aims at surfacing the mechanism behind the inhibitory actions of GSNPs against both gram-positive and gram-negative bacteria. Methods: Silver nanoparticles were fabricated using the peels of Citrus Sinensis and Punica granatum and characterized using UV-Vis Spectrophotometer, XRD, FTIR, SEM and TEM. The GSNPs were further scrutinized for their antibacterial properties against Gran negative Escherichia coli and grampositive Listeria monocytogenes and confirmed using FC analysis. Further multiple parameters were investigated for deciphering the mechanism of antibacterial action. Results: The results reveal the fabrication of 14-60 nm polydispersed GSNPs having 96% inhibition potential against both the test bacteria. Deposition of GSNPs on the bacterial surface resulting in pit formation in the bacterial cell wall and membrane causing leaking of cellular components and deactivation of bacterial enzymes were observed in the present study. Conclusion: The study proves that contrary to earlier investigations, GSNPs prepared using orange and pomegranate peels are effective against both gram positive and gram negative bacteria and may thus be used for the development of antibacterial therapies, subjected to further investigation.