title: High prevalence of multiple strain colonization of Helicobacter pylori in Korean patients: DNA diversity among clinical isolates from the gastric corpus, antrum and duodenum.
abstract: BACKGROUND
  The aims of our study were to determine the correlation of the strain variation and degree of homogeneity of infecting Helicobacter pylori (H. pylori) with their disease outcomes, and the relevance of duodenal H. pylori expression of cagA and/or vacA gene to the development of duodenal ulcer in Korean patients.
  
  
  METHODS
  One hundred and twenty bacterial colonies isolated from different anatomical sites of the stomach and duodenum were used. The study population was consisted of 40 Korean patients, 21 with duodenal ulcer, 7 with gastric ulcer, 3 with combined gastric and duodenal ulcer, and 9 with chronic gastritis. Genomic characteristics of each strain were analyzed by random amplified polymorphic DNA (RAPD) fingerprinting. The cagA and vacA genes were detected by polymerase chain reaction (PCR).
  
  
  RESULTS
  PCR-based RAPD was proved to be a reliable method for the discrimination of individual bacterial genomic characteristics. Genomic fingerprinting showed a varying degree of inter- and intra-patient variation. Thirteen patients (32.5%) were colonized by a single strain throughout the corpus, antrum and duodenum, whereas the other 27 (67.5%) harbored multiple H. pylori strains. Thirty-six isolates (90.0%) each from the corpus and antrum, and 34 (85.0%) from the duodenum, expressed the cagA gene. The prevalence of duodenal H. pylori expression of the cagA gene was not different between patients with chronic gastritis and those with duodenal ulcer. All isolates were positive for both genes vacA s1 and vacA s1a.
  
  
  CONCLUSIONS
  These results suggested that many of the H. pylori-infected Korean patients were actually colonized with mixed populations of different H. pylori strains and that the prevalence of duodenal H. pylori expression of the cagA and/or vacA gene was not correlated with the development of duodenal ulcer in Korean patients.
authors.affiliation: Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jeong Wook
authors.initials: JW
authors.lastname: Kim
authors.forename: Jae Gyu
authors.initials: JG
authors.lastname: Kim
authors.forename: Seok Lae
authors.initials: SL
authors.lastname: Chae
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Cha
authors.forename: Sill Moo
authors.initials: SM
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000032:analysis* / Q000235:genetics; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis*; D005260:Female; D016680:Genome, Bacterial; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010437:Peptic Ulcer / Q000382:microbiology*; D015995:Prevalence; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori