Intraluminal Metronidazole Powder Monotherapy for Helicobacter Pylori Infection

Helicobacter pylori (H. pylori) is the most common chronic bacterial infection in humans. The prevalence of H. pylori is about 30\~50% in the Western adult population. It is estimated that about 50% of people are infected with this bacterium in Taiwan. Many studies have shown that H. pylori is an important causal factor of chronic gastritis, peptic ulcer disease, gastric cancer and gastric lymphoma. The World Health Organization classified H. pylori as a Group 1 carcinogen in 1994. Endoscopic examination is indicated to confirm the above diagnosis for patient with H. pylori infection. Eradication of H. pylori infection reduces the risk of gastric cancer and recurrence of peptic ulcer disease. However, the eradication rate of clarithromycin-based triple therapy has been declining in recent years, probably related to the increasing resistant rate to clarithromycin. Several strategies have been proposed to overcome the declining eradication rate, including (1) extending the treatment duration of triple therapy to 14 days; (2) the use of bismuth quadruple therapy which contains bismuth, a proton pump inhibitor, and two antibiotics (usually metronidazole and tetracycline); (3) non-bismuth quadruple therapy (concomitant therapy) which contains a proton pump inhibitor and three antibiotics (usually amoxicillin, metronidazole, and clarithromycin); (4) sequential therapy which contains a proton pump inhibitor (PPI) plus amoxicillin for five days, followed by a PPI plus clarithromycin and tinidazole for another five days. The investigators aim to evaluate the efficacy of Metronidazole powder in the Intraluminal therapy for Helicobacter pylori infection while an endoscopic examination is performed.