Determination of Helicobacter pylori virulence by analysis of the cag pathogenicity island isolated from Iranian patients

BackgroundThe cag pathogenicity island (PAI), which can be divided into two parts, cagI and cagII, is the most well-known virulence factor of Helicobacter pylori.AimsWe investigated the association between genetic variations within the cag PAI (cagA and cagE in the cagI and cagT in the cagII) and clinical outcomes in Iranian patients.SubjectsA total of 231 patients including 182 patients with gastritis, 41 with peptic ulcer and 8 with gastric cancer.MethodsThe presence of the cagA, cagE and cagT genes were measured by polymerase chain reaction and the results were compared with clinical outcomes and gastric histology.ResultsThe cagA, cagE and cagT genes were found in 154 (66.7%), 90 (39.0%) and 70 (30.3%) of clinical isolates. At least 144 (62.3%) strains possessed partially deleted cag PAI (e.g., 69 [29.9%] strains were cagA-positive, but cagE and cagT-negative).ConclusionThe single genes as well as the combination of genes in the cag PAI appeared not to be useful markers to predict H. pylori-related diseases in Iranian patients. The genomic sequences of the cag PAI in Iranian strains might be considerably different from those in other geographic locations.