Background: There has been a reduction in successful H. pylori eradication rates recently, which is largely attributed to increasing antibiotic resistance. In areas of high dual clarithromycin and metronidazole resistance such as ours, Maastricht VI/Florence guidelines recommend bismuth quadruple therapy (BQT) as first line of therapy; however, the availability of bismuth was poor in Ireland until recently. Similarly, tetracycline, a component of BQT, is restricted locally, with doxycycline (D) being approved and reimbursed for most indications. Aims: To assess the efficacy of BQT-D therapy for H. pylori eradication in an Irish cohort. Methods: All patients testing positive for H. pylori in three Irish referral centres by urea breath test, stool antigen, or histology were treated prospectively with BQT-D (bismuth subcitrate 120 mg QDS, metronidazole 400 mg TDS, doxycycline 100 mg BD and esomeprazole 40 mg BD) for 14 days. Eradication was evaluated with a urea breath test (UBT) >4 weeks after therapy cessation or by stool antigen testing, as available. Outcomes were recorded and analysed according to demographics and H. pylori treatment history of the patients. Results: 217 patients completed post-eradication testing. Of which, 124 (57%) were female, with a mean age 52 years. 180 patients (83%) were treatment-naïve. A total of 165/180 (92%) of the treatment-naïve patients had successful eradication. There was no association between eradication and gender or age in this cohort (p = 0.3091, p = 0.962 respectively). A total of 29 patients received this therapy as second-line therapy, of which 22 (76%) had successful eradication. Eight patients received the regimen as rescue therapy, with seven (88%) having successful eradication. No serious adverse events were reported. Eleven individuals (6.5%) commented on the complicated nature of the regimen, with 11 tablets being taken at five intervals daily. Conclusions: BQT-D as first-line therapy for H. pylori infection is highly effective in a high dual-resistance population, achieving >90% eradication. BQT-D as a second-line treatment performed less well. Our data support BQT-D as a first-line treatment.

Resistance surveillance programmes are essential for choosing the most appropriate eradication therapy for the stomach pathogen Helicobacter pylori. This study aimed to determine H. pylori antimicrobial resistance rates in Ireland. H. pylori was cultured from patients attending four gastroenterology clinics from 2018 to 2023. Antimicrobial susceptibility testing (AST) was performed using Etests for metronidazole, clarithromycin, levofloxacin, amoxicillin, tetracycline and rifampicin and resistance classified using EUCAST guidelines. Resistance rates were compared between H. pylori treatment-naïve and previously treated patients (primary and secondary resistance, respectively). Samples from 138 culture-positive patients (mean age 49.4 ± 15.7 years, 47.1% female) were analysed. A total of 28.7% of isolates from treatment-naïve patients were susceptible to all antimicrobials tested. Primary resistance rates to metronidazole, clarithromycin, levofloxacin, amoxicillin, tetracycline and rifampicin were 44.3%, 36.5%, 18.3%, 14.6%, 9.6% and 9.6%, respectively. Primary dual resistance to clarithromycin and metronidazole was 22.6% and primary multidrug resistance was 13.0%. Secondary resistance rates were significantly higher than primary resistance rates for clarithromycin, metronidazole, dual resistance to clarithromycin and either amoxicillin, metronidazole or levofloxacin, and multidrug resistance. Female sex and older age were associated with increased risk of resistance. H. pylori resistance rates were high in our cohort. Clarithromycin-based triple therapy should no longer be used in Ireland in the absence of pre-treatment AST. Resistance to amoxicillin, tetracycline and rifampicin should be monitored closely.