Low Power He:Ne Laser Radiation in Killing Photosensitized Helicobacter pylori in Vitro

Four photosensitizers were used to test inhibitory effect of Helicobacter pylori bacteria using low power helium: neon red laser radiation. Biopsies were collected from 176 patients and H. pylori were isolated, identified and bacterial suspension was prepared. Samples of this suspension were mixed with various low concentrations of the test sensitizer. The mixture samples were exposed to different laser radiation doses. The samples were then inoculated and the inhibition zones were studied and compared with their analogues of control samples. The most effective sensitizer with optimum concentration and irradiation dose was determined. Statistical analysis of results was performed. The sensitizers' toluidine blue and the methylene blue with concentration of 100 μg/ml were able to produce the same effect of complete killing when irradiation energy density 13 J/cm. However, thionin and crystal violet sensitizers when used with the same concentration and exposed to the same laser dose, showed minor inhibitory effect. Irradiation of bacterial samples with absence of sensitizer or sensitized samples at the concentrations employed with out laser radiation has no effect on H. pylori viability in all of the experiments.