[Molecular biological mechanisms of the variability of Helicobacter pylori].

Nowadays notions on the variability of Helicobacter pylori are reviewed. Genetic polymorphism of H. pylori is manifested by variability of gene properties and their order in different strains due to recombinations occurring in these bacteria much more frequently than in other bacterial species. H. pylori belongs to those bacteria which are capable of natural transformation. Transformation is very often observed both in vitro and in vivo. A significant role in the variability of H. pylori is played by transposons and specific nature of mutagenesis. The author emphasizes that differentiation between the roles played by recombinations and mutations in the variability of H. pylori is difficult. Special attention is paid to the resistance of H. pylori strains to chemotherapeutic drugs and to the mechanisms of its development.