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

ABSTRACT

BACKGROUND: The cag pathogenicity island (PAI), which can be divided into two parts, cagI and cagII, is the most well-known virulence factor of Helicobacter pylori. AIMS: We 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. SUBJECTS: A total of 231 patients including 182 patients with gastritis, 41 with peptic ulcer and 8 with gastric cancer. METHODS: The 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. RESULTS: The 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). CONCLUSION: The 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.