Significance of cagA status and vacA subtypes of Helicobacter pylori in determining gastric histopathology: virulence markers of H. pylori and histopathology

BACKGROUND: It has been suggested that Helicobacter pylori strains containing the cytotoxin-associated gene A (cagA), and s1m1 genotype of vacuolating cytotoxin gene A (vacA) may have been associated with peptic ulcer disease. The aim of the present study was to analyze such an association of cagA presence and vacA subtypes of H. pylori with histopathological findings in patients with gastritis. METHODS: Sixty-five independent H. pylori strains isolated from Turkish patients with gastritis were analyzed. The antral biopsy specimens were processed for culture and histopathology. Histopathological features were recorded and graded according to updated Sydney system. The vacA subtypes and cagA gene were tested by polymerase chain reaction. RESULTS: Mild degree of antral density was associated with mild degree of gastric neutrophil infiltration (P = 0.010). Positive cagA status correlated significantly with the presence of atrophy (P = 0.035) and neutrophil infiltration (P < 0.001), but not with H. pylori density (P = 0.754) nor the degree of mononuclear cell infiltration (P = 0.945). The vacA subtypes were independent of gastric histopathology. The odds ratios for atrophy and neutrophil infiltration of cagA+ versus cagA- strains were 3.62 (95% confidence interval CI]: 1.04-12.66) and 53.18 (95%CI: 11.08-255.23), respectively. CONCLUSION: The presence of the cagA gene is strongly associated with atrophic and active gastritis. Distinct vacA subtypes of H. pylori appear to have no association with histopathological findings of gastritis.