文本框: STUDY ON THE RELATIONSHIP BETWEEN HELICOBACTER PYLORI STRAINS POSSESSING CAGA, VACA AND GASTRODUODENAL DISEASE Deng Z-H, Xu C-D, Zheng J, Chen S-N. Department of Pediatrics, Ruijin Hospital, The Shanghai Second Medical University, Shanghai, China Objective: Helicobacter pylori (Hp) plays an important role in chronic gastritis, peptic ulcer and gastric adenocarcinoma. H. pylori infection is contracted primarily in childhood .We have investgated the children’s infective prevalence of cytotoxin-associated gene (cagA) and vacuolating cytotoxin gene (vacA) of Hp in shanghai in order to elucidate the relationship between the characteristics of cagA and vacA of Hp and gastroduodenal disease. Methods: CagA and vacA genotype of 61 Hp strains isolated from children with chronic gastritis (CG), duodenal ulcer (DU) have been investgated by polymerase chain reaction method (PCR). Results: Among 61 Hp strains, 62.30% strains possessed cagA and 42.62%Hp possessed vacA. The positivity rate of cagA in CG and DU is similar (61.70%vs64.28%). But the positivity rate of vagA in DU was higher than that of CG (71.43%vs34.40%, X2=6.166 P<0.05). 50% strains from DU are type I strains(cagA+, vacA+) that was significantly higher than the other genotypes. Conclusion: DU patients were mainly infected by type I strains. VacA contributes to ucler as virulent factor. CagA is not reliable as a single marker for discrimination of H.plori strains with respect to gastroduodenal diseases. 0891