title: Quantitation of Helicobacter pylori in dental plaque samples by competitive polymerase chain reaction.
abstract: OBJECTIVE
  To establish a competitive PCR (cPCR) assay for quantitation of H pylori organisms in dental plaque samples.
  
  
  METHODS
  The cPCR co-amplified target H pylori DNA and a known amount of internal standard template in the same tube with the same primers directed to 0.86 kb DNA of H pylori. The internal standard was a synthesised DNA bearing the same primer recognition sites at two ends and a non-homologous core sequence as the target DNA fragment. Quantitation was based on determination of the relative, not absolute, amounts of the differently sized and [32P]-dCTP labelled products derived from H pylori DNA and the competitive internal standard after gel electrophoresis separation.
  
  
  RESULTS
  A significant correlation between known amounts of H pylori added to dental plaque samples and the results of the cPCR was found, and a standard line was developed which allowed quantitation of H pylori in the plaque samples. cPCR was performed on supragingival plaque samples from 10 adult patients with H pylori infection in the stomach, and from five adults and six children without H pylori infection in the stomach. The ranges of H pylori numbers were 1-213 (median 25), 6-76 (10), and 4-94 (14) cells/mg of dental plaque in the three groups, respectively.
  
  
  CONCLUSIONS
  cPCR is useful for quantitation of H pylori in supragingival dental plaque samples; however, the number of the organisms in dental plaque samples seems very low.
authors.affiliation: Department of Internal Medicine I, University of Ulm, Germany.
authors.forename: Q
authors.initials: Q
authors.lastname: Song
authors.forename: B
authors.initials: B
authors.lastname: Haller
authors.forename: D
authors.initials: D
authors.lastname: Ulrich
authors.forename: A
authors.initials: A
authors.lastname: Wichelhaus
authors.forename: G
authors.initials: G
authors.lastname: Adler
authors.forename: G
authors.initials: G
authors.lastname: Bode
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003773:Dental Plaque / Q000382:microbiology*; D004587:Electrophoresis, Agar Gel; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods