Investigation on cagA/vacA dominant genotypes and the coinfection of Helicobacter pylori isolates from patients in Zhejiang / 中华流行病学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To determine cagA/vacA dominant genotypes of Helicobacter pylori in patients suffering from chronic gastritis (CG) or peptic ulcer (PU), and to understand the correlation of different genotype H. pylori infection, coinfection and the gastroduodenal diseases.</p><p><b>METHODS</b>H. pylori strains were isolated from antrum and corpus samples on 42 patients with CG and 36 patients with PU. Polymerase chain reaction was used to detect cagA and the s and m regions of vacA in 156 H. pylori isolates from both antrum and corpus. The distribution of H. pylori genotypes and coinfection in CG and PU was analyzed.</p><p><b>RESULTS</b>Almost all of the isolated H. pylori strains were cagA positive. In region of vacA, only one genotype of signal region (s1a) and four genotypes of the middle region (m1, m2, m1b and m1b-m2) were found. The proportions of s1a/m1, s1a/m2, s1a/m1b, s1a/m1b-m2 and coinfection of multiple H. pylori strains in 78 isolates from antrum samples were 6.4%, 55.1%, 26.9%, 1.3% and 3.8%; and the related proportions of those from corpus samples were 6.4%, 53.8%, 25.6%, 3.8% and 5.1%, respectively. Sixteen (20.5%) patients had multiple H. pylori strains with different cagA and vacA genotypes, and multiple samples were better than single sample taken from one stomach to increase the positive proportion of coinfection.</p><p><b>CONCLUSION</b>cagA(+) s1a/m2 was the dominant genotype of H. pylori in the CG or PU patients followed by cagA(+) s1a/m1b in the Zhejiang area of China. Some of the patients were coinfected with multiple H. pylori strains of different cagA and vacA genotypes. However, there was no significant correlation between the genotypes or mixed infection with multiple strains, CG or PU.</p>