Helicobacter pylori (HP) is an etiological factor in the development of chronic gastritis, which can subsequently progress to more severe forms, including atrophic, which increases the risk of gastric cancer (GC).
Purpose of the study: assessment of HP prevalence among residents of Chita, analysis of clinical and morphological manifestations of the infection.
Material and methods. A survey and determination of HP antigen (AH) in feces were performed in 70 people. 47 participants underwent ultrasound examination of the stomach, 9 of them – control ultrasound examination 8 months after successful eradication of HP. Endoscopy of the stomach and biopsy of the mucous membrane (MM) from 5 points with morphological examination and staging according to the OLGA system were performed in 29 individuals. 38 people underwent eradication treatment with an assessment of its effectiveness by determining the AH of HP in feces 6-8 weeks after the end of therapy.
Results. A positive result of AH of HP in feces was recorded in 50 people. Persons under 39 years old were infected in 75%, 40–59 years old – in 72,7%, over 60 years old – in 64,7%. A history of chronic gastritis occurred 2 times more often, erosive and ulcerative lesions of the stomach – 4,48 times more often, the presence of gastric cancer in relatives – 3 times more often in HP-positive individuals. In the presence of bacteria, the wall thickness in the body of the stomach with ultrasound tended to thicken by 0,21 mm, in the cardiac section – by 0,18 mm (p >0,05). In a histological examination, III degree of inflammation activity by the OLGA system was diagnosed in 55.1%, IV degree in 31%, III stage of atrophy of MM in 10.3%, III type of intestinal metaplasia (incomplete colonic) in 20.7% participants. Indeterminate intraepithelial neoplasia was diagnosed in one person. 38 people held HP eradication therapy. The overall treatment efficiency was 73,3%, among those under 39 years old – 100%, 40–59 years old – 72,2%, over 60 years old – 62,5%. After successful eradication, the wall thickness of the stomach during ultrasound significantly decreased by 1–1,3 mm (p=0,013–0,05).
Conclusion. There is convincing evidence that HP is the cause of the formation of chronic gastritis with the development of atrophy, metaplasia and possible progression in the cancer. To prevent severe changes in gastric mucosa, infection should be eradicated. The best effect of anti-helicobacter therapy in the carcinoma prevention should be expected in young people.

Keywords: Helicobacter pylori, chronic gastritis, gastric cancer, ultrasound of the stomach, histology, eradication