In vitro and in vivo anti-Staphylococcus aureus activities of a new disinfection system utilizing photolysis of hydrogen peroxide

The present study aimed to evaluate in vitro and in vivo antibacterial activity of hydroxyl radical generation system by photolysis of H₂O₂, which is a new disinfection system for the treatment of oral infection diseases such as periodontitis developed in our laboratory. Firstly, generation of the hydroxyl radical by the photolysis of H₂O₂ in which 1moll^-1 H₂O₂ was irradiated with a dual wavelength-light emitting diode (LED) at wavelengths of 400 and 465nm was confirmed by applying an electron spin resonance-spin trapping technique. Secondly, the bactericidal effect of the system was examined under a similar condition in which Staphylococcus aureus suspended in 1moll^-1 H₂O₂ was irradiated with LED light, resulting in substantial reduction of the colony forming unit (CFU) of the bacteria within a short time as 2min. Finally, in vivo antibacterial effect of the photolysis of H₂O₂ on a rat model of S. aureus infection was evaluated by a culture study. Since a significant reduction of recovered CFU of S. aureus was obtained, it is expected that in vitro antibacterial effect attributable to hydroxyl radicals generated by photolysis of H₂O₂ could be well reflected in in vivo superficial bacterial infection.