Antibacterial activity of silver nanoparticles from Rhizopus spp against gram negative E.coli-MDR strains

Abstract

Development of reliable and eco-friendly process for synthesis of metallic nanoparticles is an important step in the field of nanotechnology. One of the options to achieve this objective is to use natural biological systems. In this work we have investigated extracellular biosynthesis of silver nanoparticles (AgNPs) using cell-free extract of Rhizopus spp.. Formation of AgNPs was indicated by the change in the colour of the cell-free extract from yellow to dark brown under static condition after 48 hrs of incubation. Characterization of AgNPs was carried out by UV-vis Spectroscopy which gave sharp plasmon resonance peak at 414 nm corresponding to spherical shaped nanoparticles. Transmission electron microscopy (TEM) micrograph showed formation of well-dispersed AgNPs in the range of 27 nm. X-ray diffraction (XRD)-spectrum of the AgNPs exhibited 2, values corresponding to nanocrystal. These biosynthesized AgNPs were used to study their antimicrobial activity against Multi-drug resistant (MDR) E.coli strains, by Agar diffusion method. Zone of inhibition was measured. Our results suggest that, silver nanoparticles are effective against MDR E.coli, which makes them a potential candidate for use in pharmaceutical products and medical devices that may help to prevent the transmission of drug-resistant pathogens in different clinical environments.