Das, P.

Background: The plethora of Escherichia coli (E. coli) strains that show multidrug resistance (MDR) has risen. The production of extended-spectrum beta-lactamases (ESBL) enzymes has greatly aided in this. There have been speculations on the effectiveness of silver nanoparticles in treating drug-resistant infections. Aim: This research aims to utilize Azadirachta indica (neem) leaf extract for the production of silver nanoparticles (AI-AgNPs), considering its medicinal and antimicrobial properties. Additionally, this research intends to evaluate the efficacy of these nanoparticles on resistant E. coli infections. Method: The antimicrobial activities and cytotoxicity of silver nanoparticles synthesized using neem leaves extract were tested on MDR and ESBL producing E. coli strains, as well as on Human Embryonic Kidney-293 (HEK-239) cell line, respectively. The characterization of silver nanoparticles was done by UV-Vis Spectrophotometry, Fourier-transform infrared spectrometry (FTIR), Dynamic Light Scattering-Zeta Potential (DLS-Zeta), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Energy Dispersive X-Ray Spectroscopy (EDAX). Results: The synthesized nanoparticles were spherical, smooth, and stable with an average size of approximately 74 nm. The Minimum inhibitory concentration (MIC) of AI-AgNPs was 9.5 g/ml, and the Minimum bactericidal concentration (MBC) was 121 g/ml. The IC50 value for AgNPs was 369 g/mL for HEK-293 cell line exposure. Conclusion: This study showed that the biosynthesis of silver nanoparticles from A. indica extract is highly effective, exhibiting strong antibacterial activity against multidrug-resistant bacteria while exhibiting low toxicity to normal human kidney cells. Hence, biosynthesized silver nanoparticles may be useful as antimicrobial materials for infection control because of their remarkable antibacterial activity.