Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2023

Quantitative PCR of string-test collected gastric material: A feasible approach to detect Helicobacter pylori and its resistance against clarithromycin and levofloxacin for susceptibility-guided therapy (#197)

Xinyuan Han 1 , Xiqiu Yu 2 , Xiaojuan Gao 2 , Xiangyu Wang 3 , Alfred Chin Yen Tay 4 5 , Xiaolan Wei 2 , Bing Lai 2 , Barry Marshall 4 5 , Xiuming Zhang 2 , Eng Guan Chua 5
  1. Department of Clinical Laboratory, Anhui University of Science and Technology, Anhui, Huainan, China
  2. Shenzhen Luohu People's Hospital, The Third Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, China
  3. Department of Gastroenterology, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, China
  4. Marshall Laboratory of Biomedical Engineering, International Cancer Center, Laboratory of Evolutionary Theranostics (LET), School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen, Guangdong, China
  5. Helicobacter Research Laboratory, The Marshall Centre for Infectious Disease Research and Training, University of Western Australia, Perth, Western Australia, Australia

Background: As the reduced eradication rate of Helicobacter pylori (H. pylori), we introduced string-test and quantitative PCR (qPCR) for susceptibility-guided therapy innovatively. The practicality of the string test was evaluated.

Methods: It was an open-label, non-randomized, parallel, single-center study, in which subjects tested by 13 C- urea breath test (UBT) and string-qPCR were enrolled. Based on the results of string-qPCR, we calculated clarithromycin and levofloxacin resistance rates and gave 13 C-UBT positive patients 14 days susceptibility-guided bismuth quadruple therapy. In the empirical therapy group, we retrospectively analyzed the treatment results of 13 C-UBT positive patients also treated with bismuth quadruple at Shenzhen Luohu People's Hospital from January 2021 to May 2022. The eradication rate was compared between susceptibility-guided therapy and empirical therapy groups.

Results: The diagnosis of H. pylori infection using the string-qPCR had an overall concordance rate of 95.9% with the 13 C-UBT results. Based on the results of string-qPCR, the clarithromycin and levofloxacin resistance rates were 26.1% and 31.8%, respectively. The patients who were given 14 days susceptibility-guided bismuth-based quadruple therapy achieved a high H. pylori eradication rate of 91.8%. Retrospective analysis of patient treatment data from January 2021 to May 2022 available in the hospital database revealed an overall success rate of 82.3% for those who received empirical bismuth-based quadruple therapies, which is marginally significantly lower than that of the string-qPCR susceptibility-guided group (p = 0.084).

Conclusion: The high treatment success rate of 91.8% indicates that the string-qPCR test is a valuable and feasible approach for clinical practice to help improve H. pylori treatment success rate.