Upper gastrointestinal endoscopy combined with gastric juice analysis by the medical device Endofaster for real-time assessment of H. pylori infection and molecular-based antibiotic resistance

Aims The high prevalence of antibiotic resistance of Helicobacter pylori (H. pylori) demands for antibiotic susceptibility testing (AST) to optimize treatment selection. The aim of our study was to evaluate the accuracy of a gastric juice-based molecular AST (GM-AST) concerning clarithromycin and levofloxacin in a cohort of H. pylori-positive patients identified during diagnostic gastroscopy by use of the medical device Endofaster.

Methods Patients scheduled for routine upper GI endoscopy (UGE) between February 2021 and August 2023 were prospectively recruited. Gastric juice analysis was performed by Endofaster at the beginning of endoscopic procedure and instant diagnosis of H. pylori was made based on real-time ammonium measurement using a cut-off>62 ppm/ml to indicate the presence of H. pylori. In case of intraprocedural H. pylori-detection by rapid urease test and/or Endofaster analysis, gastric juice and biopsies were collected for GM-AST and for culture-based AST (C-AST) by conventional E-test, respectively. Gastric biopsies were assessed according to the updated Sydney system. Sanger sequencing of the 23S rRNA and gyrase A genes from H. pylori was performed using gastric juice samples to detect polymorphisms associated with resistance to macrolides and fluoroquinolones. Test accuracy of GM-AST was determined using C-AST as the gold standard.

Results 461 consecutive patients were included in the study and diagnosis of H. pylori infection was made during the UGE in 178 (40.4%) individuals. Paired gastric biopsies and fluids for AST were available from 152 H. pylori-positive patients (66/86 male/female; mean age, 49.3±14.4 years). According to C-AST the resistance rates were 15.1% (23/152) for clarithromycin and 18.4% (28/152) for levofloxacin. C-AST and GM-AST results showed a very high level of concordance for clarithromycin (κ-value=0.86) and for levofloxacin (κ-value=0.81) susceptibility, respectively. The sensitivity, specificity and accuracy of GM-AST for resistance detection were 78%, 100%, and 97% for clarithromycin and 75%, 99% and 95% for levofloxacin, respectively.

Conclusions Molecular AST performed in gastric aspirate is highly accurate in the detection of H. pylori resistance to clarithromycin and levofloxacin and is comparable to conventional phenotypic AST. GM-AST in conjunction with the intraprocedural diagnosis of H. pylori is a valid tool for selecting tailored eradication regimens for the individual patient.

Conflicts of interest

Authors do not have any conflict of interest to disclose.

Publication History

Article published online:
15 April 2024