title: Diagnosis of Helicobacter pylori recurrence: relapse or reinfection? Usefulness of molecular tools.
abstract: OBJECTIVE
  Infection due to Helicobacter pylori causes many gastrointestinal diseases including peptic ulcers and gastric carcinoma. Their treatment and prevention depends on the successful eradication of H. pylori. However, even after a well-conducted treatment, H. pylori persists in about 10-30% of patients. Recurrent infections can correspond to relapse or to re-infection and require appropriate medical care. In this study, we explore retrospectively three clinical cases using molecular methods, and propose new guidelines for the diagnosis of recurrence.
  
  
  METHODS
  Ten colonies of H. pylori were selected from the primary culture of biopsy samples taken from the antrum and fundus for each patient. The genotype of each isolated colony was determined by analyzing the polymorphism of two housekeeping genes, hspA and glmM. The genome-wide composition of H. pylori strains was studied using in house macro-arrays designed.
  
  
  RESULTS
  Relapses were demonstrated by the stability of genotypes and the slight genetic variability of strains on macro-arrays. Two patients suffered from relapses, one and three years after H. pylori treatment. For the third patient, both the polymorphism of glmM and hspA genotypes and the diversity of CDSs identified on macro-arrays suggested that several episodes of re-infection occurred, 1-8 years after eradication.
  
  
  CONCLUSIONS
  For the three clinical cases, molecular methods allowed identifying the causes of recurrent infections. We suggest to study genotype to distinguish between relapse and re-infection in order to adapt the treatment and the follow-up of patients to the nature of recurrence.
authors.affiliation: a Department of Bacteriology , University of Paris-Descartes, Cochin Hospital , Paris , France ;
authors.forename: Josette
authors.initials: J
authors.lastname: Raymond
authors.affiliation: b Unit of Research and Expertise - Environment and Infectious Risk, Institut Pasteur , Paris , France ;
authors.forename: Jean Michel
authors.initials: JM
authors.lastname: Thiberge
authors.affiliation: c International Group of Data Analysis , Paris , France ;|d Department Genome and Genetics , Institut Pasteur , Paris , France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Dauga
mesh_terms: D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D017291:Clarithromycin / Q000627:therapeutic use; D004269:DNA, Bacterial / Q000032:analysis; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D005819:Genetic Markers; D005838:Genotype; D060005:Genotyping Techniques; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D016480:Helicobacter pylori / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D010802:Phylogeny; D054328:Proton Pump Inhibitors / Q000627:therapeutic use; D012008:Recurrence; D012189:Retrospective Studies
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D005819:Genetic Markers; D054328:Proton Pump Inhibitors; D000658:Amoxicillin; D017291:Clarithromycin
keywords: Helicobacter pylori; molecular typing; re-infection; recurrence; relapse