title: Is the recurrence of Helicobacter pylori infection after eradication therapy resultant from recrudescence or reinfection, in Japan.
abstract: BACKGROUND
  Reinfection of Helicobacter pylori after eradication is rare in developed countries but most often occurs within 1 year. In the present study, we attempted to differentiate between reinfection and recrudescence of H. pylori strains between 6 months and 6 years after successful eradication in Japan, a country with a high prevalence of H. pylori infection.
  
  
  METHODS
  After successful eradication of H. pylori, 274 patients were followed up by endoscopy and urea breath test. In recurrent patients, H. pylori strains isolated initially and after recurrence were compared using PCR-based restriction fragment length polymorphism (RFLP) analysis.
  
  
  RESULTS
  Recurrence of H. pylori occurred in 15 of 274 patients (5.5%) at 6 months after eradication and the annual recurrence rate was 2.0% per patient year (between 1 and 6 years). PCR-based RFLP analysis of H. pylori strains isolated initially and after recurrence showed that 62.5% (at 6 months) and 100% (after 1 years) of bacteria were of different strains.
  
  
  CONCLUSIONS
  Reinfection of H. pylori was not as rare at 6 months after eradication as reported previously, and up to 6 years after eradication, the annual reinfection rate is 2.0% per patient year in Japan.
authors.affiliation: Second Department of Internal Medicine, and Department of General Medicine, Oita Medical University, Oita, Japan.
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Okimoto
authors.forename: Kazunari
authors.initials: K
authors.lastname: Murakami
authors.forename: Ryugo
authors.initials: R
authors.lastname: Sato
authors.forename: Hajime
authors.initials: H
authors.lastname: Miyajima
authors.forename: Masaru
authors.initials: M
authors.lastname: Nasu
authors.forename: Jiro
authors.initials: J
authors.lastname: Kagawa
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kodama
authors.forename: Toshio
authors.initials: T
authors.lastname: Fujioka
mesh_terms: D000328:Adult; D000368:Aged; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D005500:Follow-Up Studies; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000628:therapy*; D016480:Helicobacter pylori / Q000145:classification / Q000235:genetics*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012008:Recurrence
chemical_list: D004269:DNA, Bacterial