Helicobacter Pylori Local Prevalence and Antibiotic Resistance

Infection with H. pylori occurs in childhood and usually leads to lifelong persistence of the pathogen. The prevalence of the infection depends on socioeconomic status (occupation, income, housing situation), especially during childhood, when the transmission occurs most frequently. H. pylori infections are most common in East Asia, e.g. China, with prevalence rates of around 60-80 %, and in Africa, with prevalence rates of partly over 80 %. In Europe, there is a south-north divide in infection rates with a higher prevalence in southern countries. The prevalence in Germany varies between 21% for the Hannover area and 44% for Saxony-Anhalt; the prevalence in children is significantly lower than in adults. Current data on the larger population in Germany are lacking. While antibiotics in combination with PPIs can be used to treat the infection, rising antibiotic resistance rates reduce effectiveness of eradication regimens.

We therefore initiated a multicenter observational study to assess the prevalence of H. pylori infection and antibiotic resistance rates in Germany. In Part A, volunteers are screened for H. pylori infection by serology. If the test is positive, a breath test is performed for confirmation and further visits and examinations follow for long-term observation. Positive patients undergoing endoscopy can enter Part B, in which biopsies are taken for antibiotic resistance, and establishment of a serum, stool and a tissue bank for molecular analysis including microbiome sequencing.

Part A - Primary study objectives - screening phase The primary aim of this part of the study is to collect data on the prevalence of H. pylori in an age- and gender-stratified random sample of the populations of Munich, Tübingen, Hannover, Regensburg, and Magdeburg and their respective surroundings. If the initial serologic test is negative, no further study visits are planned for these subjects. The serum samples already collected will be used as control samples for the serologic study. If the serologic test is positive, a breath test is performed for confirmation. If the confirmatory breath test is positive and the subject is evaluated by his/her primary doctor and deemed a candidate for endoscopic evaluation, then s/he is referred for participation in part B of the study.

Part B - Secondary study objectives - investigation phase

As secondary study objectives, the following should be investigated in H. pylori infected study participants:

* Establishment of a patient cohort for long-term observation (5-10 years). * Establishment of a serum, stool and tissue bank in this cohort for subsequent testing:

* H. pylori subtype determination for gastric cancer risk, early detection via antibody responses in serum, identification of risk factors * PCR or sequencing of H. pylori strains (from stomach biopsy or stool sample) * H. pylori isolation and antibiotic resistance testing from gastric mucosa biopsies, only to be performed as part of a clinically indicated esophago-gastro- duodenoscopy - ÖGD (for diagnosis before initiation of therapy or also after completion of therapy to monitor success or progression) * Correlation of microbiological findings with histopathological findings and atrophy markers. * Determination of H. pylori associated microbiome characteristics and microbiome changes after eradication therapy

Only patients undergoing gastroscopy for clinical indications are included into Part B of the study

• H. pylori strain analyses [Time frame: 1 year]
• subsequent medical events [Time frame: 10 years]
• risk factors for gastric cancer [Time frame: 10 years]