Real‐Time Assessment of <i>H. pylori</i> Infection to Guide Molecular Antibiotic Resistance Testing: A Combined Endoscopy‐Gastric Juice Analysis Approach

Abstract

BACKGROUND: Helicobacter pylori antibiotic resistance is the most relevant cause of treatment failure. Antibiotic susceptibility testing (AST) allows for selecting the appropriate eradication regimen. AIMS: To assess the diagnostic accuracy of gastric aspirate-based genotypic AST (G-AST) for detecting clarithromycin and levofloxacin resistance compared with conventional phenotypic AST (P-AST). METHODS: We recruited 461 consecutive patients scheduled for endoscopy. H. pylori was detected intraprocedurally using Endofaster, a novel method combining endoscopy with gastric juice analysis. For H. pylori-positive patients, we collected gastric aspirates and biopsies. G-AST was performed using DNA extracted from aspirates, with Sanger sequencing to detect polymorphisms in the 23S rRNA and gyrA genes associated, respectively, with resistance to macrolides and fluoroquinolones. P-AST was performed on H. pylori isolated from biopsies using ETEST. RESULTS: One hundred and seventy-eight (40.4%) patients tested positive for H. pylori during endoscopy. Paired gastric biopsies and aspirates were available from 152 H. pylori-positive patients. By P-AST, resistance rates were 15.1% (23/152) for clarithromycin and 18.4% (28/152) for levofloxacin. G-AST showed a high level of agreement with P-AST for clarithromycin (kappa 0.86) and levofloxacin (kappa 0.81) resistance and diagnostic accuracy of 97% and 95%, respectively. CONCLUSIONS: The novel method combining endoscopy with immediate intraprocedural gastric juice analysis for the detection of H. pylori, followed by AST in case of a positive finding, is valid and practical for tailoring eradication regimens for H. pylori infection. Genotypic AST from gastric aspirates is highly accurate for detecting clarithromycin and levofloxacin resistances.

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