Genotypic characterization of Helicobacter pylori cagA and vacA from biopsy specimens of patients with gastroduodenal diseases

Background: Helicobacter pylori infection is closely associated with gastroduodenal diseases. H. pylori infection with different vacA and cagA genotypes may result in divergent consequences. The aim of the present study was to investigate the prevalence of H. pylori infection and the correlation between cagA and vacA genotypes with the consequences of H. pylori infection in Taiwan. Methods: Genomic DNA from 97 gastric biopsies of patients with various gastroduodenal diseases was collected, and the prevalence of H. pylori infection, cagA genotypes and vacA genotypes, was analyzed by polymerase chain reaction. In addition, the correlations between cagA and vacA genotypes and the consequences of H. pylori-infection were statistically examined. Results: Our results indicated that 57.7% of this sample of patients with gastroduodenal diseases were infected with H. pylori. Prevalence of cagA⁺ strain in H. pylori-infected patients was 71.4%. All of the genotypes of the cagA⁺ H. pylori strains among our patients were type A. Prevalence of vacA signal region s1 and middle region m2 genotype in H. pylori-infected patients was 98.2% and 53.6%, respectively. Conclusions: Our study demonstrated that individuals infected with H. pylori strains that carried cagA gene and vacA s1/m2 genotypes were associated with the development of gastroduodenal diseases, compared to those infected with cagA- gene and vacA- H. pylori strains.