Helicobacter pylori antimicrobial resistance in Melbourne, Australia. Time to review therapeutic guidelines?

BACKGROUND Antimicrobial resistance (AMR) in Helicobacter pylori is a global concern. The AMR data to inform the Australian Therapeutic Guidelines is based upon data over 20 years old. AIMS To evaluate the frequency of antimicrobial resistance in H. pylori isolates from gastric biopsy specimens received in our laboratory in Melbourne, Australia To review the literature on resistance rates in Australia and compare historic data. METHODS A retrospective, observational study summarising AMR rates in all H. pylori isolates from our laboratory from 2015 to June 2020. SETTING Microbiology laboratory in metropolitan Melbourne, Australia, receiving referrals from private hospitals, gastroenterology clinics, and endoscopy suites. OUTCOME MEASURES Population minimum inhibitory concentration distributions and frequency of resistance to clarithromycin, amoxicillin, metronidazole, and tetracycline in H. pylori isolates. RESULTS 386 H. pylori isolates with susceptibility testing data were identified. The frequency of resistance in this cohort was: clarithromycin 89.9%, amoxicillin 23.5%, metronidazole 66.1%, and tetracycline 4.4%. Comparison with historical data may suggest increasing AMR rates in Australia. Main limitation is lack of treatment history to correlate AMR results. CONCLUSIONS Definitive conclusions from this cohort cannot be made, but trends suggest rising levels of primary H. pylori AMR rates in Australia. This has important implications for empirical treatment decision making and treatment outcomes. Primary H. pylori AMR requires dedicated studies and current Australian therapeutic guideline recommendations may require re-evaluation. We propose considerations for improving the management of H. pylori in Australia. A centralised public health approach to H. pylori AMR surveillance should be established. This article is protected by copyright. All rights reserved.