Fecal Molecular Susceptibility-guided Hp Rescue Therapy

The goal of this clinical trial is to evaluate the eradication efficacy and health economic benefits of individualized regimens guided by fecal molecular susceptibility testing with 7-day and 14-day courses in the rescue treatment of Helicobacter pylori infection. The main questions it aims to answer are: 1. What is the H. pylori eradication rate of the 7-day versus 14-day individualized regimens? 2. What are the safety, adherence, and cost-effectiveness of the 7-day versus 14-day individualized regimens? Researchers will compare the 7-day course group and the 14-day course group to see if the 7-day course is non-inferior to the 14-day course in terms of eradication rate. Participants will: 1. Undergo fecal H. pylori drug resistance gene testing 2. Receive randomized assignment to either 7-day or 14-day individualized treatment based on drug susceptibility results 3. Complete follow-up visits at 1 week and 4-8 weeks after stopping treatment for adverse event monitoring and 13C-urea breath test