Özet:

Objective: The synthesis of nanoparticles using microorganism and their metabolites are of increasing interest because they are potential producer of biocompatible and environmental friendly nanoparticles. Their nanoparticles can serve as potent alternatives to antibiotics against multidrug resistance bacteria (MDR). Antibacterial potential of Bacillus spp. metabolite, its silver nanoparticles and some antibiotics against multi drug resistant Salmonella spp. was evaluated. Method: The antimicrobial potential of metabolites from Bacillus spp. was determined and SNPs biosynthesized using the metabolites was characterized. The effect of physicochemical parameters on SNPs biosynthesis, antimicrobial activity of the SNPs and combination of SNPs and antibiotics against Multidrug Resistant (MDR) Salmonella strains were evaluated. Result: The bioactive metabolites of the Bacillus spp. exhibited varied antimicrobial potential against the tested MDR Salmonella spp. The metabolites were able to bio-reduced AgNO3 to Ag0 for SNPs biosynthesis. Change in colour from whitish to darkish brown and Surface Plasma Resonance (SPR) peak of 600 – 800 nm was observed. The SNPs were aggregated, rods and crystalline in shape and the sizes were 15 μm, 16 μm and 13 μm. Carboxylic acid, amino acid, alcohol, esters and aldehydes were the functional group found in the biosynthesized SNPs. The antibacterial activity of BAC1-SNPs, BAC7-SNPs and BAC20-SNPs against the MDRSA9 and MDRSA18 ranged from 6.0 – 22 mm and 11 – 20 mm. SNPs biosynthesized at pH 7 and 10mM AgNO3 had the highest antagonistic activity. Combination of SNPs and antibiotics exhibited the best antagonistic potential. Conclusion: The metabolites and SNPs biosynthesized using Bacillus spp. Metabolites exhibited antagonistic effect against MDR Salmonella spp. The combined SNPs and antibiotics had better antimicrobial activity.

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