Prevalence of cagA and vacA subtypes of Helicobacter pylori and their relations to gastrointestinal diseases / 中国实用内科杂志

ABSTRACT

Objective To investigate the prevalence of cytotoxin associated gene(cagA)and vacuolating cytotoxin gene(vacA)subtypes of Helicobacter pylori(H.pylori)in patients with upper gastrointestinal disease in Shijiazhuang area,and to assess the relationship between cagA,vacA subtypes and H.pylori related gastrointestinal disease.Methods Totally 55 H.pylori strains were isolated from patients with chronic gastrointestinal disease in Shijiazhuang area.Bacterial DNA from all these strains was extractedThe prevalence and genetic diversity in cagA 3′ region,vacA signal sequence and middle-region alleles were studied by the technique of polymerase chain reaction(PCR).Results In Shijiazhuang area,H.pylori cagA positive rate was 89.1%(49/55);cagA positive rate was not significant ly different between chronic gastritis and peptic ulcer(?~2=0.376,P=0.540).There were three vacA subtypes,including s1a/ m2 90.4%(47/52),s1a/ m1b-m2 5.8%(3/52)and s1a/ m1b 3.8%(2/52).The vacA s1a/m2 subtype showed no significant difference between chronic gastritis and peptic ulcer(?~2=0,P=1.000).Conclusion cagA~+and vacA s1a/m2 subtype of H.pylori are predominant in patients with upper gastrointestinal disease in Shijiazhuang area.There is no relationship between cagA,vacA subtypes and H.pylori related gastrointestinal disease.