# A 5-year review of Helicobacter pylori isolated from gastric biopsies at the UK Health Security Agency Gastrointestinal Bacteria Reference Unit

## TL;DR

This study reviews H. pylori resistance to antibiotics in the UK over five years, finding high resistance to metronidazole and clarithromycin, and highlights the need for updated treatment strategies.

## Contribution

The study provides up-to-date UK data on H. pylori antimicrobial resistance and emphasizes the importance of rapid testing and molecular methods for better patient outcomes.

## Key findings

- High resistance rates to metronidazole (96.1%) and clarithromycin (82.2%) were observed in treatment-refractory patients.
- Viable H. pylori recovery decreased significantly after 4 days post-collection, affecting susceptibility testing.
- Molecular testing is recommended to improve patient management due to delays in traditional testing methods.

## Abstract

Introduction.
Helicobacter pylori colonizes large proportions of the global population and is associated with the development of gastric ulcers and cancer. Antimicrobial resistance to multiple first-line antibiotics is a major contributing factor in treatment failure.

Gap statement. Within the UK, there is limited up-to-date information on antimicrobial susceptibility and resistance (AMR) rates in H. pylori.

Aim. To assess increasing gastric biopsy referrals and temporal trends in antimicrobial resistance in H. pylori recovered from gastric biopsy specimens by the Gastrointestinal Bacteria Reference Unit (GBRU) over a 5-year period (2020 to 2024).

Methodology.
H. pylori was recovered from gastric biopsies of patients predominantly with recurrent/persistent infection, collected by endoscopy across the UK through culture on selective and non-selective agar media. Antimicrobial susceptibility to metronidazole, clarithromycin, levofloxacin, amoxicillin and tetracycline was determined phenotypically by E-test.

Results. Twelve thousand six hundred sixty gastric biopsy specimens were received from which viable H. pylori was successfully recovered and susceptibility testing was performed for 40.5%, with 53.9% recovered from specimens received within 1 day following collection and decreasing to <35.0% after 4 days. Most (96.1%) were found to be resistant to metronidazole, followed by clarithromycin (82.2%) and levofloxacin (31.5%), with resistance to amoxicillin (1.2%) and tetracycline (0.2%) rarely detected.

Conclusion. Within treatment-refractory patients in the UK, there is a high prevalence of resistance to metronidazole and clarithromycin. There is an urgent need to establish UK primary resistance rates in treatment-naïve patients to support a review of regional first-line treatment regimes. These results support a need for rapid, local isolation of H. pylori by clinical microbiology laboratories to maximize patient benefit due to delays in testing, significantly reducing the likelihood of recovering viable strains for susceptibility testing, and demonstrate that implementation of molecular tests could support better patient management.