The purpose of this study is to assess efficacy of 14-day antimicrobial susceptibility test guided quadruple therapy for the rescue treatment of Helicobacter pylori infection, then comparing it with 14-day personal medication history guided therapy to tell which one has a better performance in both efficacy and safety.

Helicobacter pylori (H.pylori), which infects about 50% of the global population, has been recognized as a main risk factor of multiple gastric pathology, especially non-cardiac gastric cancer. Strong evidence supports that H.pylori eradication is an effective approach to reduce the incidence of those pathological processes. Antimicrobial susceptibility test can pick out sensitive drugs to kill Helicobacter pylori, and reduce secondary drug resistance. But, there is a lack of high quality RCT to compare its efficacy with empirical regimen in the rescue treatment.

This study aims to assess the efficacy of 14-day antimicrobial susceptibility test guided quadruple therapy for the rescue treatment of Helicobacter pylori infection. Comparing this regimen with 14-day personal Medication History guided therapy to tell which one is better in clinic practice. Alterations in H.pylori assosicated dyspepsia and safety outcomes will also be evaluated.

Inclusion Criteria:

Patients aged 18-70 with H. pylori infection. Patients with previous H. pylori eradication therapy for one or two times.

Exclusion Criteria:

Patients unable or unwilling to receive gastroscopy; Patients treated with H2-receptor antagonist, PPI, bismuth and antibiotics in the previous 4 weeks; Patients with gastrectomy, acute GI bleeding and advanced gastric cancer; Patients with known or suspected allergy to study medications; Currently pregnant or lactating; Inability to provide informed consent and other situations that could interfere with the examination or therapeutic protocol.