title: Comparison of three PCR methods for detection of Helicobacter pylori DNA and detection of cagA gene in gastric biopsy specimens.
abstract: OBJECTIVE
  To comparatively evaluate PCR and other diagnostic methods (the rapid urease test and / or culture) in order to determine which of the three PCR methods (ureA, glmM and 26-kDa, SSA gene) was most appropriate in the diagnosis of Helicobacter pylori (H pylori ) infection and also to evaluate the detection of a putative virulence marker of H pylori, the cagA gene, by PCR in biopsy specimens.
  
  
  METHODS
  One hundred and eighty-nine biopsy specimens were collected from 63 patients (three biopsies each) undergoing upper gastroduodenal endoscopy for various dyspeptic symptoms. The PCR methods used to detect H pylori DNA directly from biopsies were the glmM, 26-kDa, ureA and then cagA was used to compare the culture technique and CLO for urease with the culture technique being used as the gold standard.
  
  
  RESULTS
  Thirty-five percent of the biopsies were positive for H pylori DNA using the 3 PCR methods, while 68% of these were positive for the cagA gene. Twenty-four percent of the biopsies were negative for H pylori DNA in all PCR methods screened. The remaining 41% were either positive for ureA gene only, glmM only, 26-kDa only, or ureA + glmM, ureA + 26-kDa, glmM + 26-kDa. Out of the 35% positive biopsies, 41% and 82% were positive by culture and CLO respectively, while all negative biopsies were also negative by culture and cagA. Cag A+ infection was also predominantly found in H pylori DNA of the biopsies irrespective of the clinical diagnosis.
  
  
  CONCLUSIONS
  This method is useful for correctly identifying infections caused by H pylori and can be easily applied in our laboratory for diagnostic purposes.
authors.affiliation: Molecular Biology and Biotechnology Division, Nigerian Institute of Medical Research, P.M.B. 2013, Yaba, Lagos, Nigeria. stellaismith@yahoo.com
authors.forename: S-I
authors.initials: SI
authors.lastname: Smith
authors.forename: K-S
authors.initials: KS
authors.lastname: Oyedeji
authors.forename: A-O
authors.initials: AO
authors.lastname: Arigbabu
authors.forename: F
authors.initials: F
authors.lastname: Cantet
authors.forename: F
authors.initials: F
authors.lastname: Megraud
authors.forename: O-O
authors.initials: OO
authors.lastname: Ojo
authors.forename: A-O
authors.initials: AO
authors.lastname: Uwaifo
authors.forename: J-A
authors.initials: JA
authors.lastname: Otegbayo
authors.forename: S-O
authors.initials: SO
authors.lastname: Ola
authors.forename: A-O
authors.initials: AO
authors.lastname: Coker
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001706:Biopsy; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000382:microbiology / Q000473:pathology*; D016480:Helicobacter pylori / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D006801:Humans; D010733:Phosphoglucomutase / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014510:Urease / Q000235:genetics; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori; D014510:Urease; D010733:Phosphoglucomutase