Detection of Helicobacter pylori in bioptates of gastric mucosa of patients with gastritis and gastric ulcers using real-time PCR

Helicobacter pylori is currently believed to play an important role in the pathogenesis of gastritis, gastric and duodenal ulcers, and stomach cancer. The ability of H. pylori to colonize gastric mucosa and cause inflammation is determined by genetic factors, three of which are the best studied: the pathogenicity factors CagA and VacA and the adhesion factor BabA. We developed primer systems and probes for real-time polymerase chain reaction (RT PCR), which allowed us to detect H. pylori in specimens and to perform typing of H. pylori virulence factors CagA, VacA, and BabA. Comparison of two H. pylori diagnostic techniques, histological studies of bioptates and RT PCR, demonstrated the superiority of RT PCR in specificity and sensitivity. Typing of H. pylori demonstrated that 70–80% of strains had the cagA + /vacA s1 genotype and 10–20% had the cagA/vacA s2 genotype; babA was detected in 75–85% of all strains. H. pylori typing data did not reveal any correlations between the pathogenicity factors CagA and VacA or the adhesion factor BabA with severity of infection.