OBJECTIVETo 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.

METHODSSignal 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.

RESULTSCompared 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.

CONCLUSIONVariance 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.