Saccharomyces Boulardii Combined With Bismuth Quadruple Therapy for Helicobacter Pylori Rescue Treatment

This study aims at evaluating efficacy and safety of Saccharomyces boulardii combined with bismuth-containing quadruple Therapy versus bismuth-containing quadruple Therapy(bismuth#esomeprazole#tetracycline and furazolidone) in H. pylori rescue therapy. It is hypothesized that Saccharomyces boulardii combined with bismuth-containing quadruple Therapy is superior to bismuth-containing quadruple Therapy. Patients with confirmed failure of H. pylori eradication will be randomized to one of the treatments described above. At week 6 follow-up visits, a urea breath test#rapid urease test or helicobacter pylori stool antigen test will be performed to confirm eradication.