title: Aetiological diagnosis of infective endocarditis by direct amplification of rRNA genes from surgically removed valve tissue. An 11-year experience in a Finnish teaching hospital.
abstract: OBJECTIVE
  The aetiology of infective endocarditis (IE) can be determined directly from surgically removed valve tissue using broad-range bacterial rDNA polymerase chain reaction (PCR) followed by sequencing. We sought to assess the value of this methodology in a routine clinical setting.
  
  
  METHODS
  Broad-range PCR with primers targeting conserved bacterial rDNA sequences was applied to directly analyse valve samples from 56 patients operated on for diagnosed or suspected IE. Identification of the aetiological agent was performed by partial DNA sequencing of the 16S and 23S rDNA genes.
  
  
  RESULTS
  The final diagnosis was definite IE in 36 patients and possible IE in 2 patients, while the diagnosis of IE was rejected in 18 patients. PCR analysis from removed valve tissue was positive in 25 patients with IE. Molecular identification was consistent with the blood culture finding in 20 of these patients. The PCR approach was the only method to yield the aetiological diagnosis in additional 4 patients (2 Staphylococcus species, 1 Streptococcus bovis, 1 Bartonella quintana), all of whom had received antimicrobials before blood cultures were taken. The mean duration of preoperative antimicrobial treatment for the patients with PCR-positive valves was 19.6 (range 1-58) days.
  
  
  CONCLUSIONS
  Bacterial DNA may persist during treatment in infected valves for long periods. The PCR method is especially useful when the causative agent of IE is fastidious or when the specimen is taken during antimicrobial treatment.
authors.affiliation: Department of Medicine, Turku University Hospital, Finland. pirkko.kotilainen@utu.fi
authors.forename: Pirkko
authors.initials: P
authors.lastname: Kotilainen
authors.forename: Maija
authors.initials: M
authors.lastname: Heiro
authors.forename: Jari
authors.initials: J
authors.lastname: Jalava
authors.forename: Veikko
authors.initials: V
authors.lastname: Rantakokko
authors.forename: Jukka
authors.initials: J
authors.lastname: Nikoskelainen
authors.forename: Simo
authors.initials: S
authors.lastname: Nikkari
authors.forename: Kaisu
authors.initials: K
authors.lastname: Rantakokko-Jalava
mesh_terms: D015373:Bacterial Typing Techniques; D001473:Bartonella / Q000145:classification / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis*; D004275:DNA, Ribosomal / Q000032:analysis*; D004697:Endocarditis, Bacterial / Q000175:diagnosis* / Q000382:microbiology; D005260:Female; D005387:Finland; D006351:Heart Valves / Q000382:microbiology*; D006784:Hospitals, Teaching; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017422:Sequence Analysis, DNA; D013210:Staphylococcus / Q000145:classification / Q000235:genetics*; D013291:Streptococcus / Q000145:classification / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal