Green synthesis, characterization and antimicrobial activity of iron oxide nanoparticles with tigecycline against multidrug resistant bacterial strains

Objectives: The current study focused on the green synthesis of iron oxide nanoparticles (IONPs) using Salvia officinalis leaf extract, aiming to control nosocomial infections caused by drug-resistant bacterial pathogens. The nanoparticles were characterized and evaluated for antibacterial effectiveness. Methods: The disc diffusion assay was utilized to determine the synergistic antibacterial efficiency of the biogenic IONPs against three nosocomial bacterial pathogens namely, methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa strains. Results and conclusion: The change of color of ferric nitrate solution from orange to black color after addition of the extract preliminary indicated the formation of biogenic IONPs. The phytosynthesized IONPs were characterized using UV-Vis spectroscopy indicating the formation of a broad band at 349 nm. Moreover, X-ray powder diffraction (XRD) analysis revealed the formation of diffraction peaks positioned at 2 theta degrees of 24.80 degrees, 33.41 degrees, 35.03 degrees, 41.28 degrees, 49.15 degrees, 53.41 degrees, 57.37 degrees, 62.40 degrees and 64.31 degrees, corresponding to lattice planes of (012), (104), (110), (202), (024), (116), (214) and (300), respectively. The phytosynthesized nanoparticles revealed a high antibacterial activity against the concerned pathogens at the concentration of 200 mu g/disc with relative inhibitory zones of 21.14 +/- 0.16, 17.26 +/- 0.26, and 20.56 +/- 0.62 mm, respectively against E. coli, P. aeruginosa and MRSA strains. The biogenic IONPs revealed the highest synergistic activity with tigecycline antibiotic against E. coli followed by MRSA and P. aeruginosa strains with relative increase in fold of inhibition values (IFA) of 1.79, 1.29 and 0.93, respectively. In conclusion, the water extract of S. officinalis facilitated the green fabrication of IONPs with distinctive physicochemical properties and synergistic antibacterial activity against the tested nosocomial bacterial pathogens.