Analysis on the variance of vacA genotypes and their vacuolating toxin activity of Helicobacter pylori isolates in Zhejiang area / 中华流行病学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To analyze the variance of vacA genotypes and their vacuolating toxin activity of Helicobacter pylori (H. pylori) isolates from patients with peptic ulcer (PU) or chronic gastritis (CG) in Zhejiang area.</p><p><b>METHODS</b>Signal and middle regions of parts of seventy H. pylori strains were sequenced after T-A cloning. Vacuolating toxin activity was detected with cell culture method.</p><p><b>RESULTS</b>Compared with the reported sequences of H. pylori strain 60190 with s1a/m1 genotype, similarities of the signal-region sequences from 6 s1a-type H. pylori isolates were found to be 93.2%-98.3%, and from 1 m1b-type strain was 87.3%. When compared with the corresponding sequences of H. pylori strain 87-203 with m2 genotype, similarities of the mid-region from 4 m2-type isolates and 1 m1b-type isolates were 93.8%-97.6% and 71.7%, respectively. All 5 strains with s1a/m1 type produced vacuolating toxin activity detected by HeLa, RK-13, and SGC-7901 cell lines. Only 12 strains with s1a/m2 type produced cytotoxin in HeLa cells but 65.1% (28/43) and 62.8% (27/43) strains had cytotoxin in RK-13 and SGC-7901 cells. In RK-13 cells, 81.0% (17/21) strains with s1a/m1b produced vacuolating toxin activity.</p><p><b>CONCLUSION</b>Variance of vacA genotypes of local H. pylori isolates mainly lied in mid-region. H. pylori isolates with m2 type produced high cytotoxin in RK-13 and SGC-7901 cells, and low cytotoxin in HeLa cells. Cytotoxin strength of m1b-type strains was between strains with ml and m2 types. Vacuolating toxin activity of strains from PU group seemed obviously higher than that from CG group.</p>