Prospective, multicenter clinical study on inter- and intra-patient genetic variability for antimicrobial resistance of Helicobacter pylori.

We report on a large prospective, multicenter clinical investigation on inter- and intra-patient genetic variability for antimicrobial resistance of H. pylori.Therapy-naïve patients (n=2004) with routine diagnostic gastroscopy were included prospectively from all geographic regions of Austria. Gastric biopsy samples were collected separately from antrum and corpus. Samples were analyzed by histopathology and real-time PCR for genotypic resistance to clarithromycin and quinolones. Clinical and demographic information was analyzed in relation to resistance patterns.H. pylori infection was detected in 514/2004 (26%) patients by histopathology and confirmed in 465/514 (90%) patients by real-time PCR. PCR results were discordant for antrum and corpus in 27/514 (5%) patients, indicating inhomogeneous infections. Clarithromycin resistance rates were 17% (77/448) and 19% (84/455), and quinolone resistance rates were 12% (37/310) and 10% (32/334) in antrum and corpus samples, respectively. Combination of test results per patient yielded resistance rates of 21% (98/465) and 13% (50/383) for clarithromycin and quinolones, respectively. Overall, infection with both sensitive and resistant H. pylori was detected in 65/465 (14%) patients.Anatomically inhomogeneous infection with different, multiple H. pylori strains is common. Prospective clinical study design, collection of samples from multiple sites, and microbiological methods that allow the detection of co-infections are mandatory for collection of reliable data on antimicrobial resistance patterns in representative patient populations. ClinicalTrials.gov identifier: NCT02925091.