title: Effect of treatment failure on the CagA EPIYA motif inHelicobacter pyloristrains from Colombian subjects.
abstract: OBJECTIVE
  To evaluate effect of treatment failure oncagAandvacAgenotypes inHelicobacter pylori(H. pylori) isolates from Colombia.
  
  
  METHODS
  One hundred and seventy-six participants infected withH. pylorifrom Colombia were treated during 14 d with the triple-standard therapy. Six weeks later, eradication was evaluated by13C-Urea breath test. Patients with treatment failure were subjected to endoscopy control; biopsies obtained were used for histopathology and culture. DNA fromH. pyloriisolates was amplified using primers specific forcagAandvacAgenes. The phylogenetic relationships among isolates obtained before and after treatment were established by conglomerate analysis based on random amplified polymorphic DNA (RAPD) fingerprinting.
  
  
  RESULTS
  Treatment effectiveness was at 74.6%. Of the participants with treatment failure, 25 accepted subjected to a second endoscopy. Prevalence of post-treatment infection was 64% (16/25) and 40% (10/25) by histology and culture, respectively. Upon comparing thecagAandvacAgenotypes found before and after therapy, multiplecagAgenotypes (cagA-positive andcagA-negative) were found before treatment; in contrast,cagA-negative genotypes decreased after treatment.vacA s1m1genotype was highly prevalent in patients before and after therapy. The 3'cagAregion was successfully amplified in 95.5% (21/22) of the isolates obtained before and in 81.8% (18/22) of the isolates obtained after treatment. In the isolates obtained from patients with treatment failure, it was found that 72.7% (16/22) presented alterations in the number of EPIYA motifs, compared to isolates found before treatment.
  
  
  CONCLUSIONS
  Unsuccessful treatment limits colonization by low-virulence strains resulting in partial and selective eradication in mixed infections, and acts on thecagA-positive strains inducing genetic rearrangements incagAvariable region that produces a loss or gain of EPIYA repetitions.
authors.affiliation: Javier Andres Bustamante-Rengifo, Department of Microbiology, School of Basic Science, Universidad del Valle, Cali 760043, Colombia.
authors.forename: Javier Andres
authors.initials: JA
authors.lastname: Bustamante-Rengifo
authors.affiliation: Javier Andres Bustamante-Rengifo, Department of Microbiology, School of Basic Science, Universidad del Valle, Cali 760043, Colombia.
authors.forename: Andres Jenuer
authors.initials: AJ
authors.lastname: Matta
authors.affiliation: Javier Andres Bustamante-Rengifo, Department of Microbiology, School of Basic Science, Universidad del Valle, Cali 760043, Colombia.
authors.forename: Alvaro Jairo
authors.initials: AJ
authors.lastname: Pazos
authors.affiliation: Javier Andres Bustamante-Rengifo, Department of Microbiology, School of Basic Science, Universidad del Valle, Cali 760043, Colombia.
authors.forename: Luis Eduardo
authors.initials: LE
authors.lastname: Bravo
mesh_terms: D000328:Adult; D020816:Amino Acid Motifs; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000942:Antigens, Bacterial / Q000235:genetics* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D001706:Biopsy; D001944:Breath Tests; D017291:Clarithromycin / Q000627:therapeutic use; D003105:Colombia / Q000453:epidemiology; D004359:Drug Therapy, Combination; D016099:Endoscopy, Gastrointestinal; D005260:Female; D005838:Genotype; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology; D016480:Helicobacter pylori / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D009853:Omeprazole / Q000627:therapeutic use; D010802:Phylogeny; D015995:Prevalence; D054328:Proton Pump Inhibitors / Q000627:therapeutic use; D019105:Random Amplified Polymorphic DNA Technique; D017211:Treatment Failure; D016896:Treatment Outcome; D037521:Virulence Factors / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D054328:Proton Pump Inhibitors; C074689:VacA protein, Helicobacter pylori; D037521:Virulence Factors; C080866:cagA protein, Helicobacter pylori; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole
keywords: 3’ cagA variable region; EPIYA motifs; Helicobacter pylori; RAPD-PCR; Treatment failure