Antimicrobial activity of aqueous dispersions of silver nanoparticles against pathogens of purulent-inflammatory diseases

Abstract

Currently, metal nanostructures are widely used in medical, microbiological, and veterinary practice. Silver nanoparticles are especially promising as antimicrobial agents, becauseno published data regarding antimicrobial resistance are available. Whiledeveloping preparations based on metal nanoparticles, an important remainingissue is the choice of a stabilizer, introduction of which during the synthesis ensures the preservation of structures at the nanoscale range, and, consequently, relevant main characteristics, including biocidal properties. The object of the study was to investigate silver nanoparticle aqueous dispersions stabilized by natural and synthetic polymeric compounds. Routine strains of Gram-positive and Gram-negative bacteria were used as experimental models: S. aureus 209 P, Escherichia coli ATCC 25922, Proteus mirabilis ATCC 3177 (O-form), Klebsiella pneumoniae ATCC 31488, obtained from the Scientific Centre for Expert Evaluation of Medicinal Products. The antimicrobial activity of diverse variants of silver nanoparticle aqueous dispersions was assessed by serial dilution platingon dense nutrient medium. In this work, we examined no effect of silver nanoparticles without stabilizers, because their absence led to rapid agglomeration of nanostructures and loss of nanoscale characteristics. The highest sensitivity of Gram-positive and Gram-negative bacteria was foundto the action of ansilver nanoparticle aqueous dispersions stabilized by polyazolidinammoniumand modified with iodine hydrate ions. Drug working concentrations ranging from 0.5 to 3% had a bactericidal effect against pathogens of purulent-inflammatory diseases, and the minimum working concentration of 0.125% led to decreased colony-forming units by 2057% for diverse bacterial strains. Silver nanoparticles stabilized with sodium dodecyl sulfate showed high efficiency against the studied test strainsprobably due to the high toxicity of the stabilizer used as was previously established during a comprehensive safety assessment using biotest objects and cell cultures. In this regard, its use as a component of antimicrobial preparations is not preferred. The results of the studies showed that among the variants of silver nanoparticle aqueous dispersions, preparations stabilized with polyvinyl alcohol and polyazolidinammonium modified with iodine hydrate ions are the most promising for use in biomedical practice, because they demonstrate a high level of antibacterial activity against both Gram-positive and Gram-negative bacteria as causative agents of purulent-inflammatory diseases and a low toxicity level. This allows us to recommend them as safe and effective antimicrobial components indisinfectants, as well as antiseptic preparations for prevention and treatment of skin and soft tissue infectious diseases.