Helicobacter pylori antibiotic resistance patterns and genotypes in adult dyspeptic patients from a regional population in North Wales

Objective: Surveillance data on Helicobacter pylori antibiotic susceptibilities in Wales are limited, despite resistance being a key factor in treatment failure. A single-centre survey was undertaken over 3 years to determine local antibiotic resistance rates on isolates from dyspeptic patients in Bangor, Gwynedd (North Wales). Methods: Susceptibilities were determined for 363 isolates by disc diffusion and the Etest. Isolates were also genotyped (cagA presence and vacA allelic types). Results: Overall in vitro resistance rates were 24% for metronidazole and 7% for clarithromycin, with 4% resistant to both antibiotics. Resistant strains typically had high MICs of >256mg/L. Tetracycline resistance was identified in only one isolate whereas no isolates showed resistance to amoxicillin. There was a two-fold increase in resistance over the study period. No gender and age associations with resistance were detected. Resistant and susceptible isolates were genotypically diverse with respect to cagA/vacA type but the vacA s1m2 form was a feature of all clarithromycin-resistant isolates compared with 56% of the susceptible isolates. Conclusion: Although the overall antibiotic resistance rates of H. pylori from North Wales were low compared with many other regions in Europe, continued surveillance, particularly of high-level resistance (MIC >256mg/L), is recommended to monitor the effects of the 'test and treat' strategy for H. pylori eradication.