Small Bowel, Nutrition and Miscellaneous Poster Awards 2021 - First Prize

Dr Paul Richard Armstrong
Tallaght University Hospital Dublin

TBA (21W196)

An evolving resistant pandemic. Rising community H. Pylori resistance to Clarithromycin; an observational study.


Armstrong P, Butler T.J, Smith SI, McNamara D.


Gastroenterology Department, Tallaght University Hospital, Dublin, Ireland Trinity Academic Gastroenterology Group, Dublin, Ireland


Clarithromycin based triple therapy is commonly prescribed as first line treatment of H. pylori in Ireland. Worldwide, increased clarithromycin resistance has been reported. It is unclear whether this is due to personalised antibiotic exposure inducing resistance over time, or endemic community prevalence of a resistant strain of H. pylori, from youth. We hypothesise that older age cohorts would have had more exposure to antibiotics and that increased resistance rates with age would support a developed resistance model.


To identify resistance rates to clarithromycin based triple therapy and to compare rates according to age.


All patients referred for their first post eradication urea breath test, having received clarithromycin based triple therapy in 2020 were identified from a database. A positive UBT, delta >4 was considered a surrogate marker of clinical resistance.


In all 166 patients were identified. The overall clarithromycin resistance rate was 25%. We found no statistical difference in resistance rates across ages (Welch’s t-test p=0.24) or between age groups, divided into decades analysed via two way ANOVA. Dividing the cohort into those aged less than 45 and greater than 45, the resistance rates were also similar.


Across adult age groups, clarithromycin resistance has reached alarmingly high levels. In addition it suggests a high community prevalence of clarithromycin resistant H pylori. The authors propose that Clarithromycin based triple therapy should no longer be used without sensitivity testing as treatment for H pylori in Ireland.

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