The Antibacterial Activity of Silver Nanoparticles Produced in the Plant Sesamum indicum Seed Extract: A Green Method Against Multi-Drug Resistant Escherichia coli

The nanoparticles synthesis through biological processes is evolving a new era of research interests in nanotechnology. In usual methods silver nanoparticles are synthesized through chemical methods, having extremely toxic and flammable natures. The aim of the present study was to synthesize silver nanoparticles, through the green method of utilizing Sesamum indicum (S. indicum) extract and to determine the potential antibacterial effects of the product against multi-drug resistant Escherichia coli (E. coli). The formation and characterization of AgNPs (silver nanoparticles) were confirmed by UV-vis spectroscopy, energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscope (TEM). All 30 strains of E. coli were isolated from urine cultures of hospitalized patients (Amir Al-Momenin Hospital, Zabol, South-Eastern Iran) with urinary tract infection, 2011-2012. The minimum inhibitory (MIC) concentrations were investigated by microdilution method. The results showed that isolated E. coli were resistant to four different antimicrobial agents including ceftazidime (26.6%), cefixime (40%), tetracycline (63.3%) and erythromycin (56.6%). The highest MIC value for produced nano silver in S. indicum seed extract, was 200 ppm, against five isolates of E. coli. Considering the sufficient antimicrobial activities of nanoparticles tested in this study, they are suggested for enterobacterial infection treatment, especially in hospital environment.