The distribution and significance of cag pathogenicity island of Helicobacter pylori isolated from Chinese patients

Objective To investigate the distribution of cag pathogenicity island of Helicobacter pylori (Hp) isolated from Chinese patients and its relationship to gastroduodenal diseases. Methods cagA, cagⅠ and cagⅡ in cag pathogenicity island were determined by polymerase chain reaction(PCR) in 107 Hp strains isolated from Chinese patients. Results The amplicom was positive to cag A in 99 strains, positive to both cagⅠ and cagⅡin 66 strains and positive to cagⅠ or cagⅡalone in 27 or 8 strains respectively. One strain which was positive only to cag A but negative to other parts of the cag pathogenicity island was found. Four strains having negative cag pathogenicity island came from patients with chronic gastritis and another strain from a patient person with cardiac cancer. Conclusions The detention rate of cag pathogenicity island is high among Chinese Hp strains. In most of the strains, cag pathogenicity island is not deleted. There is no relationship between the partial deletion of cag pathogenicity island and occurrence of Hp related diseases, but primarily strains with negative cag pathogenicity island are from patients with chronic gastritis. It is suggested that cag pathogenicity island may be related to the virulence of Hp.