A preliminary study on the genetic profile of cag pathogenicity-island and other virulent gene loci of Helicobacter pylori strains from Turkey

Helicobacter pylori genetic diversity affects the function and antigenicity of virulence factors associated with the disease outcome. Gene profile was done to identify the distribution of gene loci within and outside the cag pathogenicity-island (PAI). H. pylori strains from 35 patients [21 gastritis, 14 peptic ulcer diseases (PUD)] were analyzed using PCR. The profile of the cag PAI was evaluated using primers spanning the 3 ' end, cagA, promoter region of the cagA, cagE, cagT, 5 ' end (LEC), extreme right end, plasticity region open reading frames (ORFs), oipA (Hp0638) and vacA alleles. We found few intact cag PAI in the strains examined. Deletions were found in LEC 1 (9.5% versus 14.3%), LEC2 (4.8% versus 14.3%), cagT (33.3%, versus 28.6%), cagE (28.6% versus 28.6%) and the promoter region of the cagA (19.0% versus 42.9%) of gastritis and PUD strains, respectively. The cagA gene was detectable in 57. 1 % of gastritis and 92.9% of PUD-associated strains. The cagRJ region also showed deletions for many of its genes. The oipA (Hp0638) gene was detected in 80.9% of gastritis and in 92.9% of PUD strains. The plasticity region ORFs JHP912 and JHP931 were predominant in PUD strains. The vacA-s I a-m I a genotype was predominant in PUD, while s(2)m(2) in gastrifis strains. This comprehensive analysis showed deletions in several genes within and outside the cag PAL However, cagA, oipA, JHP912, JHP931 and vacA-sla-mla were more predominant in PUD strains than gastritis-associated strains, suggesting the importance of genetic diversity on the disease progression and clinical outcome. (c) 2007 Elsevier B.V. All rights reserved.