Antibacterial Activity of Phyto-Synthesized Silver Nanoparticles From Dryopteris cristata Against Staphylococcus aureus ATCC 28923 and Escherichia coli ATCC 28922.

Introduction Nanotechnology has emerged as a vital field, particularly in synthesizing nanoparticles. Silver nanoparticles (AgNPs) are recognized for their strong antimicrobial properties against various pathogens, including  and , due to their small size and high surface area. Green synthesis using plant extracts offers an eco-friendly alternative. The rise of multidrug-resistant bacteria underscores the urgent need for new antimicrobial agents. This study investigates the antibacterial activities of AgNPs (DC-AgNPs) against  and , employing antimicrobial susceptibility testing (AST), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assessments, along with nanoparticle characterization. Materials and method The antimicrobial activity ofDC-AgNPs was evaluated using clinical isolates of  and . Bacterial inoculums were standardized to 0.5 MacFarlard (1.5 × 10 CFU/mL) and tested via a modified agar-well diffusion method. The MIC and MBC were determined using broth microdilution and sub-culturing methods, respectively. Characterization of the nanoparticles was conducted using Ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results and conclusion  was identified as the plant used to synthesize AgNPs, confirmed by the University of Ilorin, Nigeria. Phytochemical screening revealed the presence of tannins, flavonoids, glycosides, and phenolics. The AgNPs were synthesized by adding the aqueous extract to silver nitrate, resulting in a color change. Characterization via UV-Vis spectrophotometry confirmed nanoparticle formation. Antimicrobial testing showed that DC-AgNPs effectively inhibited  and , with minimum inhibitory concentrations of 125 μg and 250 μg, respectively, indicating their potential as antimicrobial agents.