Antibacterial activity of biosynthetized silver nanoparticles against Pseudomonas aeruginosa

Objective : to analyze the antibacterial effect of bioformed silver nanoparticles on the museum and clinical strain of Pseudomonas aeruginosa in vitro . Material and methods . Silver nanoparticles were obtained using metabolites of the non-pathogenic bacterium Azospirillum brasilense SR80. The size, shape, homogeneity and degree of aggregation of the obtained nanoparticles were characterized by electron microscopy, UV-visible spectroscopy and dynamic light scattering. The antibacterial effect of various concentrations of silver nanoparticles was assessed by the level of metabolic activity of cells using the resazurin test. Results . Biosynthesized silver nanoparticles exhibited antibacterial activity against the reference strain P. aeruginosa ATCC 27853 and the clinical strain P. aeruginosa . A decrease in the metabolic activity of bacterial cells was shown, depending on the concentration of nanoparticles. Maximum antibacterial activity (100% cell death) for the reference strain P. aeruginosa was achieved when the cells were treated with silver nanoparticles at a concentration of 12,5 μg/ml, for the clinical strain, complete suppression of cell growth was noted when adding nanoparticles at a final concentration of 25 μg/ml. Conclusion . Silver nanoparticles obtained by the "green" synthesis method using the cell-free extract of A. brasilense SR80 exhibit pronounced concentration-dependent antimicrobial activity against the clinical and standard strains of P. aeruginosa in vitro .