| Background: The outcome of Helicobacter pylori infection is thought to reflect an interplay between the virulence of the infecting strain, host genetics, and environmental factors. Identification of a disease-specific H. pylori virulence factors predictive of the outcome of infection remains unachieved. Recent researches suggest that jhp0917-0918 (dupA),jhp0947 and jhp0949 gene may play critical roles in the pathogenesis of H. pylori-associated Chronic gastritis and Duodenal ulcer(DU),but there are different results in different districts.Aims: 1) To investigate the distribution of H. pylori jhp0917-0918 (dupA),jhp0947 and jhp0949 gene in patients with Chronic gastritis and Duodenal ulcer in Fujian Province. 2) Explore the relation of H. pylori strains with chronic gastritis and duodenal ulcer. 3) To determine if the presence of any particular gene correlates with disease.Methods: Patients were divided into two groups,chronic gastritis and duodenal ulcer(DU). Patients with chronic gastritis were recruited by age, sex, diagnosis and pathological diagnosis. Patients with DU were excluded NSAID administration. A total of 80 H. pylori strains was isolated from gastric biopsy samples of 61 patients with chronic gastritis, 19 patients with DU. All samples were cultured in a microaerobic atmosphere, then were subcultured and extracted of total DNA. The jhp0917-0918 (dupA), jhp0947, jhp0949 gene were determined by polymerase chain reaction (PCR), and detected the sequence to validate them. Datas were analyzed with the SPSS 10.0 software package. The association about jhp genes was valued by spearman rank correlation.Results: 1) The total positive rates of jhp0917,jhp0918,jhp0947 and jhp0949 genes were 28.6%,48.8%,22.5%和10.0%, respectively. Jhp0947 gene precence in chronic gastritis strains(27.8%) was significantly higher than that in DU strains(5.3%) (P<0.05), which might be implicated in the development of chronic gastritis. Jhp0917 were present in 29.5% and 26.3% of H. pylori strains isolated from patients with gastritis and DU respectively. jhp0918 were present in 52.5% and 36.8% respectively. jhp0949 were present in 11.5% and 5.3% respectively. There were also no significant differernces in jhp0917,jhp0918 and jhp0949 genes between chronic gastritis and DU(P>0.05). 2) There was positive correlation between jhp0917 and jhp0918 (r=0.604,P<0.01), meaning that the prevalence of the jhp0917 and jhp0918 genes was closely linked to each other. There was positive correlation between jhp0947 and jhp0949(r=0.391,P>0.01), which showed that the jhp0947 and jhp0949 genes were not completely linked. 3) Among 80 isolated H. pylori strains, 21 were positive and 39 were negative for both jhp0917 and jhp0918. 5 were positive and 58 were negative for both jhp0947 and jhp0949. Positive rates of both jhp0917 and jhp0918 were not higher in the strains isolated from chornic gastritis than those from DU(P>0.05). The presence of jhp0917 and jhp0918 genes,jhp0947 and jhp0949 genes were not significantly associated with development of DU and chronic gastritis. 4) Contrasted with standard strain J99, analyzed by PubMed BLAST,the sequence of jhp0917,jhp0918,jhp0947 and jhp0949 isolated in the study to a certain extent has genetic variability. These differences may well reflect the geographic variation.Conclusions: 1) Jhp0947 gene was more likely to be found in chronic gastritis strains, which might be implicated in the development of chronic gastritis. The presence of the jhp0917,jhp0918 and jhp0949 genes was not firmly associated with both DU and chronic gastritis. 2) The prevalence of the jhp0917 and jhp0918 genes was closely linked to each other, the jhp0947 and jhp0949 genes were not completely linked. 3) The presence of jhp0917 and jhp0918 genes,jhp0947 and jhp0949 genes were not significantly associated with development of DU and chronic gastritis. 4) Contrasted with standard strain J99, the sequence of jhp0917,jhp0918,jhp0947 and jhp0949 isolated in the study has to a certain extent genetic variability. These differences may well reflect the geographic variation.
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