Biological Synthesis of Silver Nanoparticles with Aqueous Extract of Azadirachta indica Leaf and Its Antimicrobial Activity on Uropathogenic MDR and ESBL Producing Escherichia coli

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 µg/ml, and the Minimum bactericidal concentration (MBC) was 121 µg/ml. The IC50 value for AgNPs was 369 µg/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.