Helicobacter Pylori Infection Occurrence in Russia

Inclusion Criteria: * willingness to participate (based on the signed informed consent form); * age older than 12 y.o. (for subjects younger than 18 y.o. written informed consent of a legal representative was obligatory); * availability of demographic data and medical history, including previous treatment for H.pylori infection For subjects of "treatment-naïve" group: * no previous treatment for H.pylori infection in the anamnesis; * at least 6 weeks after previous use of any antimicrobial agents for any reason; * at least 2 weeks' time frame free of use of proton pump inhibitors, other anti-secretory agents and bismuth preparations. For "Previously treated" group of subjects: * infection caused by H.pylori established earlier and * not less than 6 weeks after the end of eradication therapy with at least 2 antibiotics and a proton pump inhibitor for at least 7 days, based on a patient's report Exclusion Criteria: * history of surgery on chest, stomach, gut (excluding appendectomy or laparoscopic cholecystectomy performed more than 6 month before the enrolment); * advanced stage of chronic obstructive pulmonary disease, * allergies to citruses, * pregnant and breastfeeding women.