Genotypic analysis of Helicobacter pylori strains circulating in St.Petersburg, Russia at present
Abstract number: P1731
Ferman R., Zhebrun A., Alyapkina Y., Svarval A.
A strain-specific H. pylori gene, cagA, has been recognized as a marker for strains that confer increased risk for peptic ulcer disease and gastric cancer. VacA of H. pylori is a highmolecular weight multimeric pore-forming protein that causes massive vacuolation in epithelial cell lines. As with cagA, no close homologs of vacA exist in other Helicobacter species or in other bacteria, which suggests its importance in the specific relationship of H. pylori with the human stomach. However, unlike cagA, vacA is conserved among all H. pylori strains, although significant polymorphism exists. vacA alleles possess one of two types of signal region, s1 or s2, and one of two mid-regions, m1 or m2, occurring in all possible combinations. H. pylori strains with different forms of vacA exhibit varied phenotypes and have particular associations with gastro-duodenal diseases. vacA s2 strains are rarely isolated from patients with peptic ulcers or gastric adenocarcinoma. s1/m2 forms of VacA bind to and vacuolate a narrower range of cells than s1/m1 forms and induce less damage. vacA s1/m1 strains are most closely associated with gastric carcinoma.
In our study we analysed peculiarity of H. pylori strains that are circulating in Sainkt-Petersburg at present by means of PCR method.
Materials and Methods: We have studied 30 H. pylori strains isolated from patients with chronic gastritis, gastroduodenitis, ulcer disease and gastric cancer. The patients were aged from 13 to 65. The presence of 16SrRNA, CagA, vacA was determined. Genotyping of H. pylori vacA was carry out for 14 strains.
Results: All studied strains of H. pylori revealed 16SrRNA. Estimated that 76.67% of them were cagA-positive. By genotyping vacA it was found out that s1m1 genotype was prevailing (in 57.14% of strains). It was associating with cagA gene in 87.5% cases. The s1m2 vacA genotype was estimated in 21.43% of strains and the s2m2 vacA genotype in 14.29% of strains. There was also one strain of H. pylori separated from the patient with ulcer disease that possessed the genotype cagA+/s1m1m2. The strain isolated from the patient with gastric cancer possessed the genotype cagA+/s2m2 vacA of H. pylori.
Conclusions: The fulfilled analysis showed that in Saint-Petersburg area H. pylori strains with cagA+/s1m1vacA genotype are prevailing. It is known that such strains are associated with more serious pathology therefore dynamic observation of patients with such strains is necessary.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
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