title: The role of cagA Helicobacter pylori strains in gastro-oesophageal reflux disease.
abstract: OBJECTIVE
  The role of Helicobacter pylori infection in gastro-oesophageal reflux disease is controversial. The aim of this study was to evaluate the prevalence of colonization by cagA-positive and cagA-negative H. pylori strains in the spectrum of gastro-oesophageal reflux disease.
  
  
  METHODS
  A total of 108 patients (50 male/58 female; mean age, 50.3 years) with dyspepsia and peptic ulcer or erosive gastritis/duodenitis were categorized into patients without reflux and patients with reflux oesophagitis graded from I to IV. All patients underwent upper endoscopy with biopsies of the antrum. H. pylori was detected by histology, urease test and polymerase chain reaction. The cagA status was diagnosed in the gastric biopsy by polymerase chain reaction.
  
  
  RESULTS
  The overall prevalence of H. pylori colonization in patients with reflux was 68.6% and was 70.2% in those without oesophageal disease (P = 0.862). Colonization by cagA-positive strains was also not statistically different between the two groups (31.4% versus 40.4%, P = 0.332). However, patients with grades II-IV reflux oesophagitis were less colonized by the bacterium (36.4%) than patients with grade I oesophagitis (77.5%) (P = 0.009). H. pylori cagA-positive strains were also less likely to colonize the stomach of patients with grades II-IV oesophagitis (0%), than grade I reflux oesophagitis (40%) patients and controls (40.4%).
  
  
  CONCLUSIONS
  Infection of the stomach by H. pylori and especially by H. pylori cagA strains may play a protective role against the development of the most severe forms of gastro-oesophageal reflux disease.
authors.affiliation: Department of Gastroenterology and Hepatology of the Porto Alegre School of Medical Sciences (FFFCMPA) of the Santa Casa University Hospital, Porto Alegre, Brazil. jpereiralima@terra.com.br
authors.forename: Júlio C
authors.initials: JC
authors.lastname: Pereira-Lima
authors.forename: Daniela L
authors.initials: DL
authors.lastname: Marques
authors.forename: Lucas F
authors.initials: LF
authors.lastname: Pereira-Lima
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Hornos
authors.forename: Claudia
authors.initials: C
authors.lastname: Rota
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000032:analysis*; D001426:Bacterial Proteins / Q000032:analysis*; D004942:Esophagitis, Peptic / Q000382:microbiology; D005260:Female; D005764:Gastroesophageal Reflux / Q000382:microbiology*; D016481:Helicobacter Infections / Q000150:complications* / Q000382:microbiology; D016480:Helicobacter pylori / Q000145:classification / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori