Objective: This study was aimed to characterize the Helicobacter pylori strains isolated from different geographic regions in China and different ethnic groups in Yunnan province in terms of cagA, iceA, vacA and HP0519 genes which were proposed to be related to the pathogenesis.
Methods: 150 Helicobacter pylori strains were collected from Yunnan province, Fujian province and Beijing. Chromosome DNA was extracted and polymerase chain reaction (PCR) was carried out to determine the 3' region of cagA, iceA, vacA and HP0519 status with specific primers. PCR results were analyzed statistically according to their isolated original and clinical outcomes.
Results: For cagA 3' region, 93% (139/150) of the Chinese Helicobacter pylori strains belonged to East Asian type according to the specific primer of TF/JR. Among the 150 strains, 75% (113/150) belonged to iceA1, and 19% (29/150) to iceA2. The dissemination of iceA was not associated with any of the geographic regions, different ethnic groups or different clinical outcomes. 96% (144/150) of the vacA s region belonged to s1. In the vacA middle region, m2, m1b, m1b-m2 were 57% (85/150), 27% (41/150) and 11% (16/150) respectively. However, m1a was only observed in two strains from Fujian. Neither vacA s1 nor m2 showed significant difference between Yunnan, Fujian and Beijing. However, the distribution of mlb-m2 in Yunnan was higher than that in Fujian and Beijing. In Yunnan province, the distribution of vacA s1 was not associated with different ethnic groups but m2 from Bai group was less than other two ethnic groups. The ratio of m1b in Bai group was higher than that in other groups. Both vacA' s region and m region alleles had no significant relationship with the clinical outcomes. With the 15 bp and 24 bp DNA insertion and deletion primers test, 93% (140/150) of the strains were positive. The distributions of the 15 bp and 24 bp DNA insertion or deletion were different according to the different ethnic groups.
Conclusion: By JF/TR primer, 93% of the Chinese strains cagA's 3' region belonged to East Asian type. Most of the Chinese strains vacA's allele was s1. The distribution of vacA s1 had no relationship with the clinical outcome of the isolates. From different geographic regions and ethnic groups, the distribution of vacA m region allele was different. 93% of the Chinese strains HP0519 genes had 24 bp or 15 bp insertion or deletion character. The biological meaning of the polymorphism of HP0519 needs advanced investigation.