Objective:To investigate the distribution of Helicobacter pylori (H.pylori) VacA genotypes in different gastrointestinal diseases and the relationship among each other.Methods:VacA genotypes of 108 H.pylori strains isolated from patients with chronic gastritis

peptic ulcer and gastric cancer were tested by polymerase chain reaction (PCR).Results:The frequencies of the signal allele sla

slb and the middle-region allele m1

m2 were 85 (79%)

22 (20%)

29 (27%)

77 (71%) respectively.The numbers of H.pylori strains of VacA s1a/m2 positive were 66 (61.1%).The s2 form was not found.The positive rates of VacA s la of H.pylori strains isolated from patients with chronic gastritis

peptic ulcer and gastric cancer were 65.4% (34/52)

90% (36/40) and 94% (15/16) respectively.Conclusion:The majority of H.pylori strains isolated from Chongqing patients express s1a/m2.The s1a/m2 genotype is dispersed in all of the gastrointestinal diseases associated with H.pylori.However the s2 form is not found.