title: Molecular analyses of bacterial DNA in extirpated heart valves from patients with infective endocarditis.
abstract: OBJECTIVE
  Infective endocarditis (IE) is caused by a microbial infection of the endothelial surface of the heart. Although blood culture examinations are commonly used to determine the associated bacterial species, molecular techniques, which enable rapid identification of targeted bacterial species, have recently been applied in clinical cases.
  
  
  METHODS
  Nine heart valve specimens from IE patients (six subacute cases and three acute cases) were extirpated and collected, then bacterial DNA was extracted. Bacterial species in the specimens were determined by two different molecular methods and the results were compared with those from a conventional blood culture technique. In addition, a comparison between the two molecular methods was carried out using known numbers of six streptococcal species.
  
  
  RESULTS
  The conventional blood culture method revealed the bacterial species in eight cases, while one was found to be negative. Multiple species were identified in most of the cases by both molecular methods; however, those specified by one method were not always consistent with those specified by the other. Furthermore, the species determined by the blood culture technique were not always identified by the molecular methods. We also found that the two molecular methods used in the present study were extremely sensitive to detect from 1 to 100 cells of individual oral streptococcal species.
  
  
  CONCLUSIONS
  Our results suggest that species specified by molecular methods may have disseminated incidentally into the bloodstream, so interpretation of such results should be carefully undertaken in clinical situations.
authors.affiliation: Department of Pediatric Dentistry, Division of Oral Infection and Disease Control, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Nomura
authors.forename: K
authors.initials: K
authors.lastname: Nakano
authors.forename: H
authors.initials: H
authors.lastname: Nemoto
authors.forename: T
authors.initials: T
authors.lastname: Mukai
authors.forename: H
authors.initials: H
authors.lastname: Hata
authors.forename: K
authors.initials: K
authors.lastname: Toda
authors.forename: H
authors.initials: H
authors.lastname: Yoshioka
authors.forename: K
authors.initials: K
authors.lastname: Taniguchi
authors.forename: A
authors.initials: A
authors.lastname: Amano
authors.forename: T
authors.initials: T
authors.lastname: Ooshima
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D001769:Blood / Q000382:microbiology; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis; D004697:Endocarditis, Bacterial / Q000097:blood* / Q000382:microbiology*; D005260:Female; D006351:Heart Valves / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012680:Sensitivity and Specificity; D013210:Staphylococcus / Q000302:isolation & purification; D013291:Streptococcus / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S