• Propolis nanoemulsion effect on multidrug resistant strains of Pseudomonas aeruginosa (MDR) biofilm
  • Fariba Asgharpour,1,*
    1. Cellular and Molecular Biology Research Center, Health Research Institute, Babol university of medical sciences,Babol,Iran


  • Introduction: Pseudomonas aeruginosa is a common cause of nosocomial infections and exhibits innate resistance to a wide range of antibiotics. In recent years, the current trend has been towards the identification of natural products in disinfection. Nanoparticles are able to penetrate bacteria and bacterial biofilms, so they can be a potential agent for controlling the growth of bacterial infections. In this study, our goal is to determine the antibacterial efficacy of synthesized the Propolis nanoemulsion and its combination with ciprofloxacin to obtain a synergistic effect against MDR strains of P. aeruginosa biofilm.
  • Methods: Propolis nanoemulsion (PN) was prepared by the ultrasonication method. Scanning electron microscopy and dynamic light scattering were used to measure the size and morphology of the produced nanoparticles. The PN was evaluated in vitro against ten MDR P. aeruginosa strains by disk diffusion and broth micro-dilution method. The checkerboard testing method was used to evaluate synergism among PN combined with ciprofloxacin against MDR P. aeruginosa strains.
  • Results: The Fe-SEM image reveals that the PN morphology is nearly spherical. PN, with average size 219.3 nm, was effective against MDR P. aeruginosa biofilm with MIC value of 3.2- 15 mg/ml. However, ciprofloxacin showed strong antibacterial activity even at low concentrations. According to the checkerboard results, MDR P. aeruginosa had additive effect with FIC of >0.5 to ≤1 for combining PN with CP. But, an isolate of MDR P. aeruginosa showed a synergistic antibacterial effect for combining PN (0.8 mg/ml) with CP (0.07 mg/ml).
  • Conclusion: PN was able to inhibit MDR P. aeruginosa that could be due to the reduced particle size, better nanoparticle penetration and the synergistic impact of main components in propolis. More research is needed to investigate the synergistic mechanism of PN in combination with antibiotics.
  • Keywords: Antibacterial, MDR P. aeruginosa, Nanoparticles