Evaluation of the antibacterial activity of silver nanoparticles, doxycycline, collagen and their amalgamation - An in vitro study

Biosynthesis of silver nanoparticles (AgNPs) using aqueous root extract of Delphinium denudatum (Dd). The fabricated DdAgNPs were characterized using UV-vis spectroscopy, high resolution transmission electron microscopy (HRTEM). The spectrum of brownish yellow color colloid exhibited notable peak at 416 nm. The size of DdAgNPs was ranging from 40 to 85 nm and was spherical in shape. The advent of multi-resistant pathogens has imposed the search of new strategies. In this situation, we combined silver nanoparticles (DdAgNPs) with doxycycline (DO) and collagen to assess the potency of this hybrid as a bactericidal agent against Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli, Salmonella paratyphi, Shigella dysentriae and Vibrio cholera. DdAgNPs exhibited antibacterial activity against only two test organisms but combination with collagen exhibited strong antibacterial activity against all test organisms. Doxycycline showed no activity against Escherichia coli, Shigella dysentriae and Vibrio cholera but combination with collagen exhibited antibacterial activity towards all test organisms with increased zone of inhibition except Bacillus cereus. Synergistic action of DdAgNPs, doxycycline and collagen resulted in enhanced antibacterial effect. Moreover, simultaneous action of doxycycline and DdAgNPs has made it difficult for pathogenic bacteria to develop resistance and hence, this combinational therapy can be further studied to develop new formulations of DdAgNPs in conjunction with doxycycline and collagen. (C) 2021 Elsevier Ltd. All rights reserved.