title: Infective endocarditis: does a new 16S rDNA set of primers improve the microbiological diagnosis?
abstract: BACKGROUND
  In infective endocarditis (IE), blood cultures are negative in 2.5-31% of cases because of a previously prescribed antimicrobial treatment. Molecular methods may represent an alternative to conventional microbiological techniques to identify the causative agent. The aim of this prospective study was to evaluate the performance of a new primer pair (341F/785R) for 16S rDNA amplification in heart valves compared with primers 91E/13BS already used for the diagnosis of IE. The primer pair 341F/785R was previously selected in silico to allow 16S rDNA amplification for a large coverage of bacterial species.
  
  
  RESULTS
  A total of 74 patients suspected of having IE were included in this study. IE was diagnosed in 55 of these patients using the modified Duke criteria, which was the gold standard here. 91E/13BS primers were more sensitive than 341F/785R primers: 38/55 (69.1%) samples were positive using 91E/13BS primers against 28/55 (50.9%) with 341F/785R (p = 0.013). When at least one of the two molecular methods was positive, the sensitivity and specificity of 16S rDNA amplification was 72.7% and 94.7%, respectively.
  
  
  CONCLUSIONS
  Even if the new primer pair 341F/785R seemed promising in silico, it was less sensitive for 16S rDNA amplification in heart valves than the 91E/13BS pair already used. This study underlines a lack of standardization for 16S rDNA amplification for clinical samples.
authors: a From the Laboratoire de Bactériologie-Hygiène, Centre de Biologie Pathologie, CHRU de Lille, Université de Lille 2 , Lille , France.
authors: Rémi
authors: R
authors: Le Guern
authors: a From the Laboratoire de Bactériologie-Hygiène, Centre de Biologie Pathologie, CHRU de Lille, Université de Lille 2 , Lille , France.
authors: Caroline
authors: C
authors: Loïez
authors: a From the Laboratoire de Bactériologie-Hygiène, Centre de Biologie Pathologie, CHRU de Lille, Université de Lille 2 , Lille , France.
authors: Sylvie
authors: S
authors: Armand
authors: a From the Laboratoire de Bactériologie-Hygiène, Centre de Biologie Pathologie, CHRU de Lille, Université de Lille 2 , Lille , France.
authors: Laure
authors: L
authors: Marceau
authors: a From the Laboratoire de Bactériologie-Hygiène, Centre de Biologie Pathologie, CHRU de Lille, Université de Lille 2 , Lille , France.
authors: René
authors: R
authors: Courcol
authors: a From the Laboratoire de Bactériologie-Hygiène, Centre de Biologie Pathologie, CHRU de Lille, Université de Lille 2 , Lille , France.
authors: Frédéric
authors: F
authors: Wallet
mesh_terms: D000328:Adult; D000368:Aged; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D017931:DNA Primers; D004275:DNA, Ribosomal / Q000235:genetics*; D004697:Endocarditis, Bacterial / Q000175:diagnosis* / Q000382:microbiology*; D005260:Female; D006351:Heart Valves / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S
keywords: 16S rDNA amplification; Infective endocarditis; PCR; cardiac valve