PTU-062 “The only good H. pylori is a dead H. pylori” – challenges in isolation and eradication

Introduction Helicobacter pylori (HP) resistance to antibiotics is frequent and resistance patterns are country and region-specific. There are multiple cases of repeatedly failed eradication, where bacterial isolation for culture and sensitivities is needed to inform re-treatment. HP culture, however, has a high rate of failure. The aims of this study were: To assess the success rate for HP culture, investigate the causes of failure and improve the diagnostic yield. To identify the local resistance pattern after failed eradication and develop a local eradication protocol. Methods HP culture data was collected by the microbiology laboratory and clinical information from our electronic records. We retrospectively evaluated HP cultures performed in 2017 and analysed the possible causes of false negative results. Then we developed a protocol for optimal sample processing and transportation and prospectively evaluated the diagnostic yield of the new protocol. This was integrated with a local guidance for re-treatment after failed eradication based on local resistance patterns. Results In 2017, 49 patients had endoscopic biopsy for HP culture due to failed eradication. HP was isolated in 10/49 (20%). There was no growth in 35 samples (71%) and 4 samples were contaminated. Nineteen culture negative samples were proven to be false negatives (HP positivity confirmed by other methods). Antibiotic sensitivities were: amoxicillin 100%, clarithromycin 33%, metronidazole 11%, levofloxacin 56%, and doxycycline 89%. The analysis of culture negativity indicated that the time from sampling to laboratory was the main predictor of unsuccessful isolation. The new sampling protocol involved endoscopies for HP culture being scheduled only on morning lists, Monday to Thursday, samples sent to reference lab on the same day, a minimum of 6 biopsies taken, control sampling for urease test or histology. After the implementation of the new protocol for sample processing, the rate of positive culture increased to 71% (24/34; Chi-square 21.9, p Conclusions The high failure rate of HP culture in our setting was mainly a consequence of inadequate sampling and delay in transportation to the laboratory. This issue can be effectively addressed by simple changes in local practice. The resistance rate to clarithromycin and metronidazole is high in patients who failed initial eradication and the use of these antibiotics as 2nd or 3rd line may not be justified unless sensitivity has been proven. Our findings highlight that sampling protocol is crucial to obtain positive HP cultures and assessing the local resistance pattern is important to optimise re-treatment.