Geographic Distribution of The cagA, vacA, iceA, oipA and dupA Genes of Helicobacter Pylori Strains Isolated in China

Abstract Background: There were geographical differences in the distribution of Helicobacter pylori (H. pylori) genotypes (cagA, vacA, iceA, oipA and dupA, et al). The population in different regions in China have grant different patterns of gastroduodenal diseases which are associated with these genotypes, but the geographical characteristics of H. pylori genotypes were still unknown. Materials and Methods: Gastric biopsy specimens were obtained from 348 patients from five regions in China. The regional distribution was 89 patients from Shandong, 91 from Guangxi, 57 from Hunan, 58 from Qinghai and 53 from Heilongjiang. DNA extracted from cultured isolates were analyzed by polymerase chain reaction (PCR) to determine the presence of cagA, vacA, iceA, oipA and dupA genotypes.Results: A total of 269 H. pylori isolates were obtained, of which 74 isolates were from Shandong, 78 from Guangxi, 46 from Hunan, 33 from Qinghai and 38 from Heilongjiang. The cagA gene was predominant in all the five regions (e.g. 100% in Hunan, Qinghai and Heilongjiang). The predominant vacA genotypes in the 269 isolates were s1a (88.1%) and m1(72.1%). vacA s1b was not detected in our study. In strains from Guangxi and Hunan, s1c was dominant; in contrast, s1a was dominant in Shandong, Qinghai and Heilongjiang. The prevalence of m1 strains in Heilongjiang (92.1%) was significantly higher (P<0.001) than in Shandong (60.8%) and Qinghai (51.5%). The dominant vacA subtype combination was s1a/m1 (62.8%) and detection of vacA s1a/m1 was significantly high 34 (89.5%) in Heilongjiang strains (P<0.001). The prevalence of iceA alleles in Hunan and Qinghai was much higher than that in the other three regions, and the difference was statistically significant. The oipA-positive strains were more prevalent in Guangxi (100%) and Hunan (100%) than in Qinghai (78.8%) (P<0.001). Conversely, the dupA-positive strains were less than half in Guangxi (15.4%) and Shandong (32.4%), whereas it was 73.9% in Hunan and 81.8% in Qinghai (P<0.001).Conclusions: There are significant geographic differences in the distribution of H. pylori genotypes. These datas may be used to explain the gastroduodenal diseases patterns in different geographic regions of China.