[Helicobacter pylori population characteristic in patients with diseases of gastrointestinal tract].

Aim: Study H. pylori strains circulating in St. Petersburg among patients with various gastrointestinal tract pathology as well as study of frequency of infection by H. pylori based on serological markers data among this group of patients.
Materials and Methods: By using serological method 162 individuals with various chronic diseases of stomach and duodenum were examined. The presence in blood serum of IgG against H. pylori bacterial antigen and IgG against its toxin--CagA was studied. 129 patients were examined bacteriologically, biopsy samples of stomach mucous membrane were studied. PCR in real time format was used for study of H. pylori strains (49) and biopsy samples (36) of stomach mucous membrane.
Results: The analysis performed showed that on the territory of St. Petersburg H. pylori strains containing cagA gene predominate (81.63% of the isolated strains). Genotyping of strains by vacA showed that s1m1 genotype was more frequent (in 57.14% of cases). The fraction of CagA positive strains in patients in St. Petersburg is maximum for stomach cancer (90.8%), whereas for peptic ulcer disease and gastritis it is 64.7% and 72.2%, respectively. In patients with stomach and duodenum pathology the parameters of seropositivity for H. pylori were significantly higher than in individuals without clinical manifestations of H. pylori infection (86.72% against 65.09%; p < 0.05).
Conclusion: The data obtained on increase of fraction of CagA positive strains among H. pylori circulating in St. Petersburg determine the importance of conducting eradication H. pylori.