Antibacterial and cytotoxic activity of metronidazole and levofloxacin composites with silver nanoparticle

The aim of the work is to to ascertain their antibacterial activity, as well as the toxic effects toward human cells of composites of silver nanoparticles immobilized by electron-beam technology onto crystals of antimicrobial agents metronidazole and levofloxacin

The assessment of antibacterial activity and cytotoxic action of silver naonparticled metronidazole and levofloxacin composites was carried out using the MTT-test. Objects of study of antibacterial activity were three strains of microorganisms: Staphylococcus aureus ATCC25923, Escherichia coli dH5α, Pseudomonas aeruginosa ATCC9027. For the investigation of cytotoxic action, cells of HEK 293 line obtained from human kidney embryos were used. Nanocomposites of metronidazole and levofloxacin were tested at concentrations known as the minimum toxic dose of antibiotics and at concentrations reduced/increased in 2 times.

Immobilization of silver nanoparticles on the surface of metronidazole and levofloxacin by electron-beam technology gives a different effect on their antibacterial and cytotoxic activity. Nanocomposites of metronidazole exhibit a weaker antibacterial effect on E. coli than metronidazole alone, while levofloxacin nanocomposites have higher antibacterial activity compared to levofloxacin alone. Nanocomposites of the levofloxacin, compared to free levofloxacin, are characterized by a higher antibacterial effect towards gram-negative bacteria (E. coli), but practically do not differ in activity toward P. aeruginosa and S. aureus. Immobilization of silver nanoparticles on metronidazole crystals does not affect on its cytotoxicity relative to pseudonormal human cells line HEK 293, while the nanocomposites of levofloxacin with silver are more toxic to these cells than levofloxacin alone.