Gastric cancer (GC) is a globally important disease. The discovery of Helicobacter pylori (H. pylori) demonstrated that the human stomach is not a sterile environment, and recent advances in molecular biology have led to the detection of large populations of microorganisms in the stomach. A growing number of studies have elucidated differences in the microbiota of patients at various stages of GC development. Evidence from insulin‐gastrin transgenic (INS‐GAS) and human gastric microbiota‐transplanted mouse models have further demonstrated the potential causality of microbiota in the development of GC. To date, H. pylori is still thought to be the strongest risk factor for GC. H. pylori interacts with non‐H. pylori commensals and affects the composition of the gastric microbiota. This review provides an overview of the relationship between the gastric microbiota and GC, including the mechanisms of microbe‐associated carcinogenesis, the clinical value of the microbiota as a GC biomarker, and the potential of modulating the microbiota for GC prevention or therapy.

ObjectivesTo explore the outcomes of Helicobacter pylori infection treatments for naïve patients in the real-world settings.DesignA retrospective observational study.SettingSingle tertiary level academic hospital in China.ParticipantsWe identified patients initially receiving quadruple therapy for H. pylori infection from 2017 to 2020 in whom eradication was confirmed (n=23 470).Primary outcomeEfficacy of different initial H. pylori infection treatments.Secondary outcomeResults of urea breath test (UBT) after H. pylori eradication.ResultsAmong 23 470 patients who received initial H. pylori treatment, 21 285 (90.7%) were treated with amoxicillin-based regimens. The median age of the patients decreased from 2017 to 2020 (45.0 vs 39.0, p<0.0001). The main treatments were therapies containing amoxicillin and furazolidone, which had an eradication rate of 87.6% (14 707/16 784); those containing amoxicillin and clarithromycin had an eradication rate of 85.5% (3577/4182). The date of treatment, age, antibiotic regimen and duration of treatment showed correlations with the failure of H. pylori eradication in a multivariable logistic regression analysis. Finally, positive UBT results after eradication clustered around the cut-off value, in both the 13C-UBT and 14C-UBT.ConclusionsThe major H. pylori infection treatments for naïve patients were those containing amoxicillin and furazolidone, which offered the highest eradication rate. The date of treatment, age, antibiotic regimen and duration of treatment were risk factors for the failure of H. pylori eradication. Additionally, positive UBT results after eradication clustered around the cut-off value.

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IntroductionHelicobacter pyloriis the most well-known risk factor for gastric cancer. Antibiotic resistance is the main reason for the failure ofH. pylorieradication, and understanding the antibiotic resistance before treatment may be the main determinant of successful eradication ofH. pylori. This study aims to evaluate the efficacy and safety of quadruple therapy based on faecal molecular antimicrobial susceptibility tests for the first-line eradication ofH. pyloriinfection.Methods and analysisThis is a single-centre, single-blind, randomised controlled trial, enrolling 855 patients withH. pyloriinfection. Patients are randomised to three groups for a 14-day treatment: group A: amoxicillin- and clarithromycin-based bismuth-containing quadruple therapy (BQT) (rabeprazole 10 mg, amoxicillin 1 g, clarithromycin 500 mg and colloidal bismuth 200 mg two times per day); group B: clarithromycin medication history-based BQT (rabeprazole 10 mg, amoxicillin 1 g, furazolidone 100 mg (with clarithromycin medication history)/clarithromycin 500 mg (without clarithromycin medication history) and colloidal bismuth 200 mg two times per day); group C: antimicrobial susceptibility test-based BQT (rabeprazole 10 mg, amoxicillin 1 g, clarithromycin 500 mg (clarithromycin-sensitive)/furazolidone 100 mg (clarithromycin resistant) and colloidal bismuth 200 mg two times per day). The primary end point is the eradication rate. The secondary end points are the incidence of adverse events and compliance.Ethics and disseminationThis study was approved by the Ethics Committee of Second Affiliated Hospital, School of Medicine, Zhejiang University (Number 20230103). The results will be published in the appropriate peer-reviewed journal.Trial registration numberNCT05718609.