Consensus and variable region PCR analysis of Helicobacter pylori 3 ' region of cagA gene in isolates from individuals with or without peptic ulcer

The clinical outcome of Helicobacter pylori infection may be associated wit h the cagA bacterial genotype. To investigate the cagA status of H. pylori- infected patients and the relationship between cagA and peptic ulcer diseas e, gastric biopsy specimens from 103 Caucasian patients in Brazil were anal yzed by PCR. Since allelic variation in cagA exists and distinct H. pylori subgenotypes may circulate in different regions, PCR using primers for a va riable 3' region of the cagA gene according to a Japanese methodology and f or a consensus cagA 3' region used in Western methods was used for cagA det ection, cagA was present in 53 (71%) of 75 H. pylori-positive cases when an alyzed by the consensus region method and was associated with duodenal ulce r disease (P = 0.02), but not with gastric ulcer (P = 0.26), when compared to patients with duodenitis or gastritis. The variable region PCR method wa s able to detect 43 (57%) cagA-positive cases within the same group of H. p ylori-positive patients and showed three subtypes of cagA (A, B/D, and C) t hat were not associated with clinical outcome. However, in 8 (18%) of the c ases, more than one subtype was present, and an association between patient s with multiple subtypes and disease outcome was observed when compared to patients with isolated subtypes (P = 0.048). cagA was a marker of H. pylori strains for duodenal ulcer disease in our population, and in spite of the differences in the 3' region of the cagA gene, the Japanese methodology was able to detect the cagA status in most cases. The presence of multiple sub genotypes of cagA was associated with gastric ulcer.