The aim of our study will be to assess in an open-label, multicenter, randomized controlled trial whether a tailored therapy guided by a non-invasive antibiotic susceptibility test on stool samples achieves higher Helicobacter eradication rates than an empiric antibiotic regimen. For this purpose, consecutive patients with dyspeptic symptoms, diagnosis of Helicobacter pylori infection and naïve to eradicating treatments will be allocated to either of the two intervention arms.

Study design:

Eligible subjects will be defined by the positivity to at least 2 out of 4 tests for Helicobacter pylori infection diagnosis (i.e. histology, rapid urease test, urea breath test and serology). Stool samples and gastric biopsy specimens of eligible patients will be analyzed at enrollment, using real time-polymerase chain reaction (RT-PCR) to detect bacterial DNA mutations conferring resistance to amoxicillin, clarithromycin, tetracycline, metronidazole, and levofloxacin. Participants allocated to the tailored intervention arm will receive an antibiotic combination therapy according to the result of stool sample molecular analysis. Participants allocated to the empiric intervention arm will be treated by either a quadruple concomitant or bismuth-containing regimen, according to the 2017 European Helicobacter pylori management guidelines. In all participants, infection eradication will be evaluated 30 days after treatment end, using urea breath test. We will also assess the diagnostic accuracy of the RT-PCR on fecal samples in detecting bacterial antibiotic resistances, using the RT-PCR on gastric biopsy specimens as the reference standard.

Inclusion Criteria:

• presence of dyspeptic symptoms, according to Rome IV criteria;
• Helicobacter pylori infection diagnosis by the positivity of at least 2 out of 4 diagnostic tests (i.e. histology, rapid urease test, urea breath test, and serology);
• naive to Helicobacter pylori treatment;
• written informed consent.

Exclusion Criteria:

• previous Helicobacter pylori treatment;
• diagnosis of gastric cancer or other diseases requiring surgery;
• contraindications to upper endoscopy;
• chronic diarrhea;
• known allergy to any drugs used in the intervention and control arm.

Investigators performing urea breath test 30 days after the end of the treatment (assessment of the primary outcome: eradication rate) will not be aware of participants' allocation and received therapy. Moreover, two independent investigators will perform RT-PCR on stool samples and gastric biopsy specimens, blinded to the other test results.