Detection of Helicobacter pylori cagA gene in gastric biopsies, clinical isolates and faeces

Purpose: Helicobacter pylori infection is common in the developing countries. The cagA gene is a marker of pathogenicity island (PAI) in H. pylori. The aim of this study was to determine the prevalence of cagA among dyspeptic patients in Bahrain directly from gastric biopsy and stool specimen. Methods: A total of 100 gastric biopsy samples, 16 clinical isolates and 44 faecal specimens were collected from Bahraini adult dyspeptic patients. cagA gene of H. pylori was assessed using polymerase chain reaction (PCR). Results: The cagA gene was detected in 59 (59%) from biopsy specimens, 10 (62%) clinical isolates and in 10 (22.7%) faecal specimens. The detection of cagA positive H. pylori was significantly higher in patients with duodenal ulcer (80%) compared to those with other endoscopic finding (42%) (P<0.05). Conclusions: Using PCR to detect cagA gene directly from biopsy is a rapid and reliable technique. However, using stool specimen for genotyping in our patients showed reduced sensitivity.