In the clinical HelicoPTER study, data on the frequency and severity of H. pylori infections and the antibiotic resistance situation in Germany will initially be collected in a cross-sectional study. Knowledge of the resistance situation is necessary for the selection of suitable empirical treatment regimes. In addition, molecular detection methods are to be compared with conventional microbiological methods in order to be able to diagnose resistance more quickly. Furthermore, long-term monitoring of study participants who have tested positive for H. pylori will be carried out. Specific parameters will be identified that will make it possible to recognise H. pylori infected patients at a high risk of gastric cancer or already precancerous lesions as a result of the infection at an early stage.