The status of the cagA gene does not predict Helicobacter pylori-associated peptic ulcer disease in Singapore

Discrepancies among reports from different geographical regions worldwide o n the association between the presence of cagA and peptic ulcer disease pro mpted this study on the predictive value of the cagA gene in Helicobacter p ylori-associated gastroduodenal diseases in the Singapore population. H. py lori strains were obtained from 169 patients with a peptic ulcer, 83 with n on-ulcer dyspepsia, and nine with gastric cancer. The presence of the cagA gene was evaluated by polymerase chain reaction (PCR). The expected 400 bp PCR product coding for the cagA gene was present in 232/261 (89%) H. pylori isolates. Of these, 151/169 (89%) strains from patients with peptic ulcer, 73/83 (88%) strains from patients with nonulcer dyspepsia and 8/9 (89%) st rains from cancer patients were positive for the cagA gene. There was no st atistically significant difference between the prevalence of cagA-positive strains from patients with distinct clinical outcomes (p > 0.05). The preva lence of cagA-positive strains in the Singapore population is high regardle ss of clinical disease status. The results suggest that the cagA gene is no t a universal virulence marker of H. pylori.