The Frequency of dupA Gene among Clinical Isolates of Helicobacter pylori and its Association with Gastro-Duodenal Diseases

Helicobacter pylori is a gram negative, spiral shaped bacterium which colonises in the human gastric tract. It plays an important etiologic role in gastric ulcers and gastroduodenal disorders. The dupA gene is one of its virulence factors that seems to cause duodenal ulcers in human hosts on the other hand some studies indicated the converse relationship between this gene and gastric cancer disease. The aim of the current study was to determine the prevalence of dupA gene of H. pylori isolated and find its relationship with gastroduodenal diseases.

This cross-sectional descriptive study was performed on 150 H. pyloripositive isolates obtained from patients with dyspeptic symptoms. DNA was extracted from biopsies and the dupA gene status was determined by Polymerase Chain Reaction (PCR). Statistical analyses were performed to find any significant relationship between this virulence factor and clinical outcomes.

A total of 131 H. pylori samples, 123 (94%) were confirmed to be H. pylori positive based on 16S rRNA gene. The dupA gene was found in 41 (33.33%) of H. pylori-positive samples. There was not any significant relationship between this gene and duodenal disease, however there was a reverse association between this gene and gastric cancer (P<0.05). Furthermore, we found significant association between the presence of dupA gene, smoke usage (P< 0.04) and flatulence (P<0.03).

As the results show, dupA gene can be the predictable marker for severity of gastric disorders such as gastric cancer. Similarly to what has been seen with other H. pylori virulence markers, there may be wide regional differences in the distribution of dupA. Extended molecular epidemiology researchers in other populations are recommended.