title: [Prevalence of cag A and vac A subtypes of Helicobacter pylori in Guangzhou].
abstract: OBJECTIVE
  To investigate the prevalence of cytotoxin associated gene (cag A) and vacuolating cytotoxin gene (vac A) subtypes of Helicobacter pylori (Hp) from patients with upper gastrointestinal diseases in Guangzhou, and to assess the relationship between cag A, vac A subtypes and Hp related gastrointestinal diseases.
  
  
  METHODS
  191 Hp strains were isolated from patients with different gastrointestinal diseases in Guangzhou. Bacterial DNA from all these strains was extracted. cag A and vac A alleles were typed using PCR with specific primers.
  
  
  RESULTS
  In Guangzhou, Hp cag A positive rate was 85.3% (163/191). cag A positive rate was significantly higher in gastric cancer and peptic ulcer than that in chronic gastritis (P < 0.05). There were six vac A mosaicisms, including 168 for s1a/m2 (88.0%), 14 for s1a/m1b (7.3%), 6 for s1b/m2 (3.1%), 1 for s1b/m1b (0.5%), 1 for s2/m2 (0.5%) and 1 for s1a/m1b-m2 (0.5%). The rate of vac A s1a/m2 subtype in chronic gastritis, peptic ulcer and gastric carcinomas was 87.5% (70/80), 87.5% (84/96) and 93.3% (14/15) respectively. There was no significant relationship between cag A and vac A subtypes (P > 0.05).
  
  
  CONCLUSIONS
  cag A(+) and vac A s1a/m2 subtype of Hp is predominant in patients with upper gastrointestinal diseases in Guangzhou, cag A(+) strains are further more common in patients with gastric cancer and peptic ulcer.
authors.affiliation: Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University of Medical Sciences, Guangzhou 510080, China.
authors.forename: Y
authors.initials: Y
authors.lastname: He
authors.forename: P
authors.initials: P
authors.lastname: Hu
authors.forename: X
authors.initials: X
authors.lastname: He
authors.forename: Z
authors.initials: Z
authors.lastname: Zeng
authors.forename: Y
authors.initials: Y
authors.lastname: Cui
authors.forename: C
authors.initials: C
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D002648:Child; D005260:Female; D005756:Gastritis / Q000382:microbiology; D005838:Genotype; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010437:Peptic Ulcer / Q000382:microbiology; D013274:Stomach Neoplasms / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori