Half of the world's population is infected with Helicobacter pylori. Strong evidence supports that H.pylori eradication is an effective approach to reduce the risk of developing gastric cancer. However, eradication rates of first-line therapy decreased over years due to the rapidly emerging antibiotic resistance of H. pylori worldwide. An ideal rescue therapeutic regimen to cure refractory H.pylori infection is currently warranted.~Traditional sequential therapy failed to achieve an ideal eradication rates (over>95%) as a third line treatment in the region with high antibiotic resistance. The investigator's study aims to evaluate the efficacy 14-day modified sequential therapy in the patients with two or more treatment failure, and whether the adverse effects of this new modified sequential therapy are tolerable.
The purpose of this study is to assess efficacy of a 14-day sequential therapy for the rescue treatment of refractory Helicobacter pylori infection, and whether it is safe while maintaining an ideal eradication rates.