Clinical research of the distribution of H.pylori ureA, vacA s1 gene and cagA subtype distribution in patients with digestive diseases in Guangzhou

Objective To detect the distribution of H.pylori ureA, vacA s1 gene and cagA subtype(ABC, ABD, ABAB, AAD, et al) in patients with digestive diseases in Guangzhou and investigate the relationship with the pathological findings of gastric mucosa.Methods A total of 227 randomly selected gastric mucosa from patients with digestive diseases were enrolled in the research, including 46 without pathological changes, 130 with chronic gastritis, 29 with peptic ulcer, 15 with atrophic gastritis and 7 with gastric cancer.Real-time PCR assay were used to detect Helicobacter pylori ureA gene and vacA s1 gene.EPIYA motifs in the 3′ region of cagA were amplified by conventional PCR followed by subtype sequencing. The conserved gene ureA was used to detect H.pylori infection.Results Among the 227 patients with digestive diseases, 50.7% (115/227) patients were H.pylori positive, in which 91.3%(105/115) carried vacA s1 and 78.3% (90/115) carried cagA. Four types of cagA-EPIYA subtype were detected, including ABC 17.8%(16/90), ABD 78.9%(71/90), AAD 2.2%(2/90) and ABAB 1.1%(1/90).In the non-pathological change group, 32.6% (15/46) were H.pylori positive, in which 28.3% (13/46) carried vacA s1 and 26.1% (12/46) carried cagA;in chronic gastritis group, it was 48.5% (63/130), 43.8% (57/130) and 36.2% (47/130), respectively;in ulcer group, it was 72.4% (21/29), 65.5% (19/29) and 55.2% (16/29), respectively;in atrophic gastritis group, it was 66.7% (10/15), 66.7% (10/15) and 66.7% (10/15), respectively;in gastric cancer group, it was 85.7% (6/7), 85.7% (6/7) and 71.4% (5/7), respectively.The distribution of H.pylori among the 4 groups had statistical significance (χ2=16.72;P<0.01). H.pylori was more prevalent in ulcer, atrophic gastritis and cancer group than in inflammation group and non-pathological change group (χ2=16.02;P<0.01).In patients infected by H.pylori, there was no significant difference in the distribution of vacA s1 gene as high virulence factors among non-pathological change, inflammation, ulcer, atrophic gastritis and cancer group (χ2=2.00;P=0.74), as well as cagA (χ2=3.44;P=0.49) and EPIYA subtypes (χ2=3.66;P=0.45).Conclusions H.pylori infection is significantly associated with the pathological change of gastric mucosa for patients with digestive diseases in Guangzhou, while the relationship with the pathogenicity of H.pylori with high virulence genotype is not significant.More samples and diseases reclassification are needed to make an advanced analysis of the effect of H.pylori with high virulence in gastrointestinal diseases development. Key words: Stomach diseases; Helicobacter pylori; Gastric mucosa; Polymerase chain reaction