Bacterial Quorum-Sensing and Virulence Factors Manipulation Using Er:YAG Laser Irradiation

Objectives: Past research has proven that Lasers are efficient in affecting tissues and bacteria, utilizing physical properties of photon energy. All bacteria possess the ability to communicate amongst themselves (Quorum Sensing). We sought to investigate the effect of Laser irradiation at sub-lethal powers on bacterial quorum sensing.
Methods: The effect of Er:YAG (2940 nm wavelength; Syneron, Yokneam, Israel) Laser irradiation at sub lethal doses on bacterial cross communication and virulence factors was investigated. Assessment of post irradiation Quorum Sensing levels was performed for both Vibrio harveyi and Streptococcus mutans using an automated plate reader. Swimming ability of irradiated Vibrio harveyi was determined by measurement of motility halos on modified agar plates. Strep. mutans biofilm formation was inspected under confocal microscopy and biomass of biofilm formed post irradiation was assessed using qPCR.
Results: Following irradiation, significant dose dependent changes in Quorum Sensing levels were recorded for both bacterial strains. Swimming ability of Vibrio harveyi was significantly affected post irradiation as well as Strep. mutans biofilm production.
Conclusions: Results suggest on a possible unique effect of Laser irradiation on bacterial characteristics via the quorum sensing cascade.