Study on antimicrobial activities of synthesized nanoparticles against drug resistant Enterotoxigenic Escherichia coli and Salmonella typhi isolated from potable water and their cytotoxic effects on human intestinal epithelial cell line

Abstract

In the present study, potable water samples were collected from different sites of Gwalior city for isolation of Enterotoxigenic Escherichia coli (ETEC) and Salmonella ser. Typhi (S. Typhi). Selective and differential media were used to isolate and identify the strains. Isolated strains were further characterized using biochemical and molecular methods. Specific primer pairs for the virulent genes of S. Typhi and ETEC were used in PCR. Out of the 8 sites, 5 sites were found positive for ETEC and 3 sites were positive for S. Typhi. newlineIsolates from each contamination point were screened for susceptibility to existing antimicrobials. Genotypic profiling was done for the presence of antimicrobial resistance gene in the respective isolates. Further this study comprised of metallic nanoparticles to explore their antimicrobial activity against identified drug resistant pathogens. Zinc, Silver, Copper and Gold nanoparticles were synthesized by biological and chemical methods. Synthesized nanoparticles were further characterized by UV-Visible spectroscopy and Electron Microscopy followed by their antimicrobial activity against drug-resistant ETEC and S. Typhi. The minimum inhibitory concentration and minimum bactericidal concentration were evaluated and found to be much effective than the conventional drug. newlineThe study further explored with the synergistic effects of existing antimicrobials and nanomaterials. The antimicrobial activity of Au- and Ag-nanoparticles was increased in synergistic study. newlineCytotoxicity of synthesized nanoparticles was performed, using sulforhodamine B assay on human intestinal epithelial cell line. Genotoxicity of nanoparticles was performed by chromosomal aberrations and micronucleus test. Both assays in Swiss mice bone marrow cells revealed that low and intermediate doses were non-toxic as compared to high dose. Further, by analyzing all the parameters, the most effective nanoparticle was selected for acute profiling. In acute toxicity, lethal dose was evaluated for Gold nanoparticles.