Consensus and Variable Region PCR Analysis of Helicobacter pylori 3′ Region of cagA Gene in Isolates from Individuals with or without Peptic Ulcer

Abstract

The clinical outcome of Helicobacter pylori infection may be associated with the cagA bacterial genotype. To investigate the cagA status of H. pylori-infected patients and the relationship between cagA and peptic ulcer disease, gastric biopsy specimens from 103 Caucasian patients in Brazil were analyzed by PCR. Since allelic variation in cagA exists and distinct H. pylori subgenotypes may circulate in different regions, PCR using primers for a variable 3 region of the cagA gene according to a Japanese methodology and for a consensus cagA 3 region used in Western methods was used for cagA detection. cagA was present in 53 (71%) of 75 H. pylori-positive cases when analyzed by the consensus region method and was associated with duodenal ulcer 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 was able to detect 43 (57%) cagA-positive cases within the same group of H. pylori-positive patients and showed three subtypes of cagA (A, B/D, and C) that were not associated with clinical outcome. However, in 8 (18%) of the cases, more than one subtype was present, and an association between patients 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 subgenotypes of cagA was associated with gastric ulcer.

cagE as a biomarker of the pathogenicity of Helicobacter pylori

“…The PCR was performed as proposed by Rota et al 20,21 . and the cagE gene was investigated according to Sozzi et al 22 .…”

Variation in number of cagA EPIYA-C phosphorylation motifs between cultured Helicobacter pylori and biopsy strain DNA

“…Different PCR-based assays have been described for molecular typing of EPIYA phosphorylation motifs both in gastric biopsy specimens (Gunn et al, 1998;Monstein et al, 2010;Rota et al, 2001) and in co-cultured H. pylori isolates (Argent et al, 2005). Some studies established a correlation between genotypes and disease outcome, while other studies did not (Acosta et al, 2010;Ahmad et al, 2009;Sgouras et al, 2009;Shokrzadeh et al, 2009).…”

Relationship between caga-positive Helicobacter pylori infection and risk of gastric cancer: a case control study in Porto Alegre, RS, Brazil

“…H. pylori may cause damage to the gastric epithelial cell by mechanisms related to pathogenic factors of the bacteria, mainly by the proteins coded by the genes vacA, cagA, iceA and babA (21) . H. pylori cagA-positive strains have been associated with gastric ulcer (7,25) , duodenal ulcer (7,30) and gastric cancer (1,7,8,28,31) . Approximately 60%-80% of H. pylori strains express a high molecular weight protein, denominated CagA, coded by the cagA gene.…”

“…One gastric biopsy specimen from the antrum was subjected to PCR, targing the ureA, 16SrRNA and cagA gene detection, using sets of synthetic oligonucleotides primers, as described elsewhere by Rota et al (30) . The primers HPU18N (5'-CCCATTTGACTCAATGCGATG-3') and HPU54N (5'-TGGGATTAGCGAGTATGTCGG-3') were used to amplify a 132-bp product from the 16SrRNA gene, and the primers UREA1 (5'-GCCAATGGTAAATTAGTT-3') and UREA2 (5'-CTCCTTAATTGTTTTTAC-3') were used to amplify a 394-bp product from the ureA gene.…”