Analysis of Helicobacter pylori genotypes in Afghani and Iranian isolates

The geographical variation in Helicobacter pylori genotypes is an observed phenomenon. Cytotoxin associated genes A (cagA) and E (cagE), and vacuolating cytotoxin (vacA) genotypes of H. pylori are associated with peptic ulcer disease (PUD). This study compared the distribution of these genotypes in Iranian and Afghani isolates and their association with clinical outcomes. H. pylori infected patients, as proven by positive culture, were recruited prospectively. A total of 70 patients, 55 Iranian (26 men and 29 women, mean age 48 +/- 18 years) and 15 Afghani immigrants (13 men and 2 women, mean age 34.8 +/- 11 years) living in Tehran, Iran were enrolled in this study. DNA was extracted from isolated H. pylori and polymerase chain reaction was carried out to determine the cagA and cagE status and vacA alleles. The number of gastric cancer, peptic ulcer and gastritis cases was 11, 23 and 36, respectively. The cagA positive isolates were more common in Iranian (67%) than Afghani isolates (60%). cagE was positive in 53% of Afghani compared to 51% of Iranian isolates. The most common vacA s-region genotype was s1; 80% in Afghani and 67% in Iranian. The slml was a frequently observed genotype in Afghani strains (53%) while s1m2 (47%) was more common in strains isolated from Iranian patients. There is a difference in the H. pylori strains between Iranian and Afghani groups, for instance Iranian isolates were similar to European isolates while Afghani isolates were similar to isolates from India. However, there was no significant association between cagA, cagE and vacA genotypes and clinical outcomes in Iranian and Afghani patients.