Effect of Helium/Neon Laser Radiation, Sodium Hypochlorite, and Other Selected Disinfectant Combinations on the Killing of Disinfectant-Resistant <i>Staphylococcus </i><i>a</i><i>ureus</i> Isolated from Wounds

Laser as a new phototherapeutic approach was proposed with its basic theory since the beginning of the last century. It was used in wound disinfection, particularly with antibiotics, as well as disinfectant-resistant bacterial pathogens. This lethal photosensitization is thought to be due to membrane-induced damage arising from free radicals generated by photoactivated sensitizers and also membrane and wall damage induced by sodium hypochlorite disinfectant. The laser was a helium-neon (He/Ne) gas type with a measured output at 5 mW (Laser Beacon, I. N. C., Michigan, USA) used in the present study. Toluidine blue 0 and povidone-iodine as photosensitizers were used. Hypochlorite (Britain Drug Home) was utilized. Selected disinfectant-resistant strains of S. aureus were tested. Using the minimal inhibitory concentration of different antibiotics was assessed, and its effect on total viable counts (TVC’s) of strains was concluded. The effect of laser, sodium hypochlorite, and laser-sodium hypochlorite on selected strains of S. aureus was observed. There were significant decreases in TVC’s after exposure to the laser–sodium hypochlorite combination compared to laser, povidone-iodine, or sodium hypochlorite. Exposure of bacterial strains to chemical disinfectants at subminimal inhibitory concentrations caused a sharp decrease in total viable counts of disinfectant-resistant S. aureus, particularly after exposure to the laser-povidone-iodine-sodium hypochlorite combination, with significant statistical differences in viable counts of the pathogen tested (P ≤ 0.05). The present study revealed that the effect of sodium hypochlorite reduced the TVC’s moderately, whereas the combination of laser and sodium hypochlorite showed a dramatic and consistent reduction in TVC’s with minimal variation, revealing strong and reliable antimicrobial synergy.