Helicobacter pylori in patients can be killed by visible light

Background: Helicobacter pylori colonizes the mucus layer of the human stomach and may cause peptic ulcer and adenocarcinoma. Novel antimicrobial approaches are sought due to the occurrence of antibiotic resistance and consequent treatment failure. We report here that H. pylori is susceptible to inactivation by blue light. Study Design/Materials and Methods: A controlled, prospective, blinded, trial of endoscopically delivered blue light to eradicate H. pylori in regions of the gastric antrum, in 10 patients between the ages of 21 and 80 who tested positive for H. pylori. Light (405 nm) (40 J/cm ²) was delivered to a 1-cm diameter spot in the gastric antrum via optical fiber passed through the endoscope and weighed biopsies were taken from treated and control spots and colonies quantitatively cultured. Results: Blue light killed 5 logs of bacteria in vitro. The mean reduction in H. pylori colonies per gram tissue between treated and control spots was 91% (7.4 ± 4.8 × 10⁶ vs. 8.1 ± 1.9 × 10⁷, two-tailed P<0.0001). Some patients had reductions approaching 99%. No differences were observed on histological examination of light-treated and control gastric tissue. Conclusion: Blue light phototherapy may represent a novel approach to eradication of H. pylori, particularly, in patients who have failed standard antibiotic treatment.