Analysis of Helicobacter pylori antimicrobial susceptibility and virulence genes in gastric mucosal biopsies in the United Arab Emirates.

AIM To determine the virulence attributes (presence of cagA and vacA genes) of Helicobacter pylori , and presence of clarithromycin resistance genes in gastric mucosal biopsy samples obtained in the United Arab Emirates. METHODS DNA was extracted from antral gastric biopsy samples from 91 dyspeptic patients. Real-time PCR and melting curve analysis were used to identify patients infected with H. pylori and to further identify strains containing the A(2142/43)G or the A(2142)C mutations that are associated with clarithromycin resistance. PCR was also used to identify cagA - and vacA -positive strains. RESULTS Real-time PCR analysis detected the presence of H. pylori in 55 (60%) samples. Thirty-six pathogen-positive samples contained at least one of three point mutations associated with clarithromycin resistance. The vacA gene was present in 40 (72.7%) and cagA was present in 41 (74.5%) of the positive samples. Both genes were present in 36 (65%) of the positive samples. The presence of each clarithromycin-inducing mutation was largely independent of the others. Mutation at one position, A(2142/43)G, was strongly associated with the presence of both the vacA gene and the cagA gene. CONCLUSIONS A high proportion of gastric mucosal biopsies obtained in the UAE is positive for genes associated with clarithromycin resistance. This may have implications for treatment of the infection.