title: [Helicobacter pylori: cagA analysis and vacA genotyping in Chile. Detection of a s2/m1 strain].
abstract: BACKGROUND
  The genes cagA and vacA encode H pylori virulence factors.
  
  
  OBJECTIVE
  To genotype these genes in H pylori strains isolated from patients with upper gastrointestinal symptoms.
  
  
  METHODS
  We studied 50 patients who underwent an upper gastrointestinal endoscopy, with positive culture for H pylori. Detection of cagA and vacA genotyping was done using polymerase chain reactions.
  
  
  RESULTS
  The gene cagA was detected in 19 samples (38%). Signal sequences s1 and s2 of vacA gene were detected in 16 samples each (32%). There was simultaneous amplification of s1 and s2 in 6 samples and they were not detected in 9 samples. The middle region of vacA was m1 in 9 samples, m2 in 29 samples and there was simultaneous amplification of m1 and m2 in 12 samples. In 16 samples (32%), more than one type of signal sequence or medial region was detected. Of those patients in whom vacA was the only genotype detected, 15 were s2/m2, 7 were s1/m1, 4 were s1/m2 and 1 was s2/m1.
  
  
  CONCLUSIONS
  In these patients, the infection with cagA- H pylori strains, predominates, the prevalence of infection with s1 or s2 strains is similar and the predominant medial region is m2.
authors.affiliation: Facultad de Ciencias Biológicas y Facultad de Medicina, Universidad de Concepción, Sección de Gastroenterología, Hospital Asociación Chilena de Seguridad, Concepción, Hospital San Borja Arriarán, Santiago, Chile. h.pylori@usa.net
authors.forename: A
authors.initials: A
authors.lastname: Martínez
authors.forename: C
authors.initials: C
authors.lastname: González
authors.forename: F
authors.initials: F
authors.lastname: Kawaguchi
authors.forename: R
authors.initials: R
authors.lastname: Montoya
authors.forename: A
authors.initials: A
authors.lastname: Corvalán
authors.forename: J
authors.initials: J
authors.lastname: Madariaga
authors.forename: J
authors.initials: J
authors.lastname: Roa
authors.forename: A
authors.initials: A
authors.lastname: García
authors.forename: F
authors.initials: F
authors.lastname: Salgado
authors.forename: H
authors.initials: H
authors.lastname: Solar
authors.forename: M
authors.initials: M
authors.lastname: Palma
mesh_terms: D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics*; D002677:Chile; D005767:Gastrointestinal Diseases / Q000382:microbiology*; D005838:Genotype; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D010437:Peptic Ulcer / Q000382:microbiology; D016133:Polymerase Chain Reaction; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori
vernacular_title: Helicobacter pylori: análisis de cagA y genotipificación de vacA en Chile. Detección de una cepa s2/m1.