Helicobacter pylori Primary and Secondary Antimicrobial Resistance through 22 Years of Culture Experience (2000-2021)

Abstract

Abstract Background Helicobacter pylori gastritis is considered to be an infectious disease, irrespective of an individual’s symptoms and stage of disease. Until now, most consensus recommendations were based on empirical treatments conditional on local antimicrobial susceptibility patterns. The aim of this study was to provide information about the primary and secondary antimicrobial resistance rates in Gipuzkoa, Basque Country, Spain, and to share the experience of H. pylori culture followed by susceptibility testing. Methods In total, 31,406 gastroduodenal biopsies and 2,641 string tests from patients over the age of 15 were plated on selective media, isolating H. pylori in 36.7% of biopsies and 50.7% of string tests. Antibiograms could be performed in 96.6% (12,399/12,835) of H pylori isolates. Overall, 10.8% (1,343/12,399) of antibiograms were obtained from second or subsequent samples from the same patient. PCRs were also used to detect H. pylori and its clarithromycin resistance. Results Primary resistance to amoxicillin and tetracycline was unusual, 0.6% and 0.2%, respectively. Primary resistances to clarithromycin and metronidazole remained constant through the 22-years of study, around 14% and 30% respectively. Primary resistance to levofloxacin tripled from 7.6% in 2000 to 21.7% in 2021 (p < 0.001) and grew with patient’s increasing age. Simultaneous resistance to clarithromycin, metronidazole and levofloxacin was 1.8%. Secondary resistance to all antimicrobials was significantly higher than primary resistance. Conclusion We encourage Microbiology laboratories to perform culture and/or PCR of H. pylori followed by antimicrobial susceptibility testing, allowing physicians to follow a tailored treatment strategy.