Endophytic Streptomyces sp . BDUSMP R07 from Solanum trilobatum (Thuthuvalai) for the biosynthesis of bactericidal silver nanoparticles against multi resistant Enterococcus spp

The ever-increasing emergence of drug resistant Gram positive Enterococcus sp is a major health concern globally for therapeutic options to the existing antimicrobial compounds. In the present study we de scribe one-pot green synthesis of antimicrobial silver nanoparticles (AgNPs) using th e cell free supernatant (CFS) of an endophytic Streptomyces sp BDUSMP R07. The UV-visible spectroscopy (UV-vis) absorption of colloidal AgNPs showed a surface plas ma resonance (SPR) centered at 425 nm. The synthesized AgNPs were further characterized by Fourier Transform Infra-red spectroscopy (FTIR), Energy dispersive X- ray (EDAX) and X-ray diffraction (XRD) analysis. Dynamic light scatterin g (DLS) analysis revealed particles with an average diameter of 125.8 nm. Tra nsmission Electron Microscopic (TEM) study showed the size of the nanoparticles to be in the range of 20- 48 nm with spherical shape. Zeta potential analysis indicated - 36.5 mV characteristic for stable AgNPs. Biosynthesized AgNPs from CFS (5%) showed significant antimicrobial activity against Gram positive E. faecalis irrespective of whether the strain is drug resistant or non- drug resistant. The results sugge st that Streptomyces sp BDUSMP R07 could be exploited for the fabrication of AgNPs with potential therapeutic applications in nanomedicine especially for Enterococcus infections.