Figure 4

Antimicrobial effect of silver nanoparticles against normal and multidrug-resistant human bacteria E . coli by disc diffusion method. (a) Plate showing increasing inhibition zone of E. coli (DH5α) with increasing concentration of nanoparticles: clockwise from top 0.51, 1.02, 2.55, 3.57, and 5.1 μg in a total volume 100 μl in water. (b) Plate showing increasing inhibition zone of MDR E. coli (DH5α-MDR) with increasing concentration of nanoparticles: clockwise from top 0.51, 1.02, 2.55, 3.57, and 5.1 μg in a total volume 100 μl in water. (c) Graph of antimicrobial assay of the nanoparticles on E. coli (DH5α ) in which 10, 20, 50, 70, and 100% nanoparticle solution corresponds to 0.51, 1.02, 2.55, 3.57, and 5.1 μg of silver nanoparticles in 100 μl solution, respectively. (d) Graph of antimicrobial assay of the silver nanoparticles on MDR E. coli (DH5α-MDR). Vertical bars indicate mean of three experiments ± standard error of mean (SEM). Different letters on bars indicate significant differences among treatments (P = 0.05).