title: Distribution of Helicobacter pylori in north China.
abstract: OBJECTIVE
  To compare the distribution of virulence-associated genotypes of Helicobacter pylori (H pylori) in two areas of north China with different gastric cancer risk and furthermore probe into the pathogenicity of the bacterium.
  
  
  METHODS
  Gastric biopsies were taken from 355 subjects from Zhuanghe, a high risk area of gastric cancer, and 136 subjects from Shenyang, a low risk area of gastric cancer. A total of 149 H pylori strains isolated from these patients were studied by PCR for differences in the genotypes of cagA, vacA, and iceA.
  
  
  RESULTS
  In patients with high risk for gastric cancer, higher frequencies of vacA s1 or s1m1b genotypes were found as compared to those from the low risk area.
  
  
  CONCLUSIONS
  There is significantly different distribution of H pylori genotypes between Zhuanghe and Shenyang areas in north China.
authors.affiliation: Cancer Institute of the First Affiliated Hospital of China Medical University, 155 Northern Nanjing Street, Heping District, Shenyang 110001, Liaoning Province, China.
authors.forename: Yue-Hua
authors.initials: YH
authors.lastname: Gong
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
mesh_terms: D002681:China / Q000453:epidemiology; D005753:Gastric Mucosa / Q000166:cytology / Q000382:microbiology* / Q000473:pathology; D005838:Genotype; D005843:Geography; D016480:Helicobacter pylori / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D016133:Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000453:epidemiology*