Importance of Helicobacter pylori cagA and vacA status for the efficacy of antibiotic treatment.

BACKGROUND Virulence factors of Helicobacter pylori are associated with peptic ulcer disease and may be also associated with the efficacy of treatment. AIMS To determine the relation between the vacA and the cagA status of H pylori, clinical disease, and treatment outcome. PATIENTS 121 patients with H pylori infection and peptic ulcer disease or functional dyspepsia were treated by quadruple antibiotic therapy in two groups for one and two days, respectively. METHODS DNA was isolated from gastric antral biopsy specimens, taken before and after treatment, and the vacA and cagA status was determined by polymerase chain reaction and reverse hybridisation. RESULTS Peptic ulcer disease was significantly associated with the vacA s1 type, and cagA positivity, but not with the vacA m type. Treatment efficacy was significantly higher in patients with peptic ulcer disease, or infected with cagA+/vacA s1 strains. CONCLUSIONS The strong association between the cagA and vacA status and peptic ulcer disease was confirmed. Cure rates seem to be higher for patients with cagA+/vacA s1 H pylori strains, which is consistent with the higher cure rate observed among ulcer patients compared with functional dyspepsia patients. Therefore, treatment studies may require stratification for presence of ulcers as well as H pylori genotypes.