Supplementary Material for: Appropriateness of Repeating <b><i>Helicobacter pylori</i></b> Culture and Susceptibility Testing Following Failure of Individualized Antibiotic Therapy

<b><i>Background:</i></b> Current guidelines recommend direct <i>Helicobacter pylori</i> culture and antibiotic susceptibility testing following 2 failed eradication attempts. If this process is followed and yet subsequent treatment is unsuccessful, it is unclear whether susceptibility testing should be repeated. This is the first study to examine the appropriateness of repeated <i>H. pylori</i> culture and susceptibility testing following failure of individualized treatment. <b><i>Methods:</i></b> Between 2007 and 2014, consecutive patients who underwent at least 2 upper gastrointestinal endoscopies with <i>H. pylori</i> culture and susceptibility testing at our institution following several treatment failures were retrospectively identified. Antibiotic susceptibility was recorded and linked to demographic data. <b><i>Results:</i></b> A total of 68 cultures from 34 patients were included (12 (35.3%) men, 41.4 ± 16.6 years), and 20 (58.8%) cultures had a different antibiotic susceptibility profile on repeat testing (8 (23.5%) with new susceptibility and 13 (38.2%) with new resistance). Acquired resistance to clarithromycin, levofloxacin and metronidazole was observed in 9 (26.5%), 2 (5.9%) and 10 (29.4%) cultures, respectively. Subjects with resistance to ≤1 antibiotic at baseline were more likely to develop resistance to at least 1 antibiotic on subsequent culture, compared to subjects with resistance to ≥2 antibiotics at baseline (13 (100%) vs. 5 (23.8%), p < 0.01). <b><i>Conclusion:</i></b> Repeating <i>H. pylori</i> culture and susceptibility testing usually yields new antimicrobial susceptibility data. However, the clinical usefulness of this approach remains unclear.