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 1 mol lL1 H2O2
was irradiated with a dual wavelength-light emitting diode (LED) at wavelengths of 400 and 465 nm 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 1 mol lL1 H2O2 was irradiated with
LED light, resulting in substantial reduction of the colony forming unit (CFU) of the bacteria within a short time as
2 min. 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.