Extended susceptibility testing for refractory Helicobacter pylori infection: regional testing should guide antimicrobial decision making.

BACKGROUND: Helicobacter pylori (H. pylori) is a Gram-negative bacterium and common cause of gastritis. Antimicrobial treatment typically involves two agents and is prescribed empirically however therapy can be complicated by drug allergies or previous, unsuccessful regimens. Recent data from Europe suggests rising resistance to commonly used agents but contemporary data relevant to UK populations, particularly following the COVID-19 pandemic is limited. This study aimed to report susceptibility testing results in refractory cases of H. pylori infections to evaluate local resistance patterns, inform treatment strategies, and compare findings with data from the European Registry on H. pylori management. METHODS: A retrospective multi-centre cohort study was conducted between September 2018 and September 2023 at North West London Pathology (London, UK), a central laboratory operating through a hub and spoke model, to assess extended antimicrobial susceptibilities in gastric biopsy samples from patients with refractory H. pylori infection. Antimicrobial susceptibilities were assessed using minimum inhibitory concentration methods as per contemporaneous European Committee on Antimicrobial Susceptibility Testing guidelines. Results were compared with European data. RESULTS: A total of 193 individual isolates were identified. Mean resistance rates were low for tetracycline (2.3%) and amoxicillin (7.3%), moderately low for rifampicin (14.0%), moderate for levofloxacin (27.3%) and high for metronidazole (82.7%) and clarithromycin (75.5%) across the study period. Levofloxacin had a trend of increasing susceptibility (p = 0.10) and rifampicin of increasing resistance (p = 0.31) throughout the study. Resistance rates were significantly higher for the non-naïve North West London cohort compared with the European non-naïve cohort for metronidazole (p < 0.001), amoxicillin (p < 0.01), and clarithromycin (p = 0.02). CONCLUSION: These findings emphasize the necessity of tailored treatment approaches, informed by regional susceptibility patterns. As antimicrobial resistance continues to evolve a proactive and adaptive approach to treatment strategies remains paramount to effectively treat H. pylori infection and mitigate associated clinical and financial burdens. CLINICAL TRIAL: Not applicable.