Analysis of Helicobacter pylori antimicrobial susceptibility and virulence genes in gastric mucosal biopsies in the United Arab Emirates
Alfaresi, M.S.; Abdulsalam, A.I.; Elkoush, A.A.
Indian Journal of Gastroenterology Official Journal of the Indian Society of Gastroenterology 26(5): 221-224
2007
ISSN/ISBN: 0254-8860 PMID: 18227572 Document Number: 611082
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. 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. 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. 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.