Potential of silver nanoparticles synthesized using low active mosquitocidal Lysinibacillus sphaericus as novel antimicrobial agents

Abstract

Silver nanoparticles (AgNPs) were synthesized using extracellular filtrates of some Lysinibacillus sphaericus (Ls) strains under simple conditions. Ls synthesized AgNPs showed the optical absorption peaks at 388–412 nm as detected by UV-visible spectrophotometer. Transmission electron micrographs of bacterial synthesized AgNPs revealed that they were polycrystalline with spherical, hexagonal, cuboidal, rod and irregular shapes. The average diameter of the tested AgNPs were ranged from 14–21 nm and they were negatively charged as detected by DLS (−18.2 to −28.9). FTIR spectra showed the presence of nitrogenous biomolecules capping the synthesized AgNPs. The filtrates of tested Ls strains showed nitrate reductase activity (1.45–2.56 µmol/ml/min). Tested AgNPs showed bactericidal activity against Gram positive and Gram negative bacteria, fungicidal activity against yeast and filamentous fungi, and virucidal activity against rotavirus. In addition, it showed synergistic antimicrobial effect to cephradine and nizoarm against all tested microorganisms. Cytotoxicity test revealed the safety of the tested nanoparticles at tested concentrations.

Finally, Ls strains represent microbial sources for ecofriendly, simple and economic biosynthesis of antimicrobial AgNPs. Also, this research may contribute to the medicinal chemistry and pharmaceutical industry for the development of new products used for the public health.

Keywords:

• AgNPs
• antibiotic synergism
• bactericidal
• cytotoxicity
• fungicidal
• Lysinibacillus sphaericus
• virucidal

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors thank and appreciate the financial support of National Research Center for this study under the project No AR111108.