Genotypic Resistance Guided Therapy for Refractory H. Pylori Infection

The inviestigators aimed to compare the efficacy of genotypic resistance guided versus susceptibility testing guided therapy in the third line treatment for refractory H. pylori infection. Hypothesis:The investigators hypothesized that genotypic resistance guided sequential therapy is non-inferior to empiric therapy in the third line treatment for refractory H. pylori infection. Methods: This multicenter, open label, parallel group, randomized trial will be conducted since 2017.07.20. Adult (≥20 years old) patients who failed from at least two eradication therapies for H. pylori infection will be enrolled. Genotypic and phenotypic resistances will be determined in patients who failed from at least two eradication therapies by polymerase-chain-reaction with direct sequencing and E-test and agar dilution test, respectively. Eligible patients will be randomized into either one of the treatment groups (A) genotypic resistance guided therapy; or (B) susceptibility testing guided therapy. Outcome Measurement The primary outcome is the eradication rate in the third line treatment (genotypic versus susceptibility testing guided therapy) according to intention-to-treat (ITT) analysis.