title: Frequent detection of Streptococcus tigurinus in the human oral microbial flora by a specific 16S rRNA gene real-time TaqMan PCR.
abstract: BACKGROUND
  Many bacteria causing systemic invasive infections originate from the oral cavity by entering the bloodstream. Recently, a novel pathogenic bacterium, Streptococcus tigurinus, was identified as causative agent of infective endocarditis, spondylodiscitis and meningitis. In this study, we sought to determine the prevalence of S. tigurinus in the human oral microbial flora and analyzed its association with periodontal disease or health.
  
  
  RESULTS
  We developed a diagnostic highly sensitive and specific real-time TaqMan PCR assay for detection of S. tigurinus in clinical samples, based on the 16S rRNA gene. We analyzed saliva samples and subgingival plaque samples of a periodontally healthy control group (n = 26) and a periodontitis group (n = 25). Overall, S. tigurinus was detected in 27 (53%) out of 51 patients. There is no significant difference of the frequency of S. tigurinus detection by RT-PCR in the saliva and dental plaque samples in the two groups: in the control group, 14 (54%) out of 26 individuals had S. tigurinus either in the saliva samples and/or in the plaque samples; and in the periodontitis group, 13 (52%) out of 25 patients had S. tigurinus in the mouth samples, respectively (P = 0.895). The consumption of nicotine was no determining factor.
  
  
  CONCLUSIONS
  Although S. tigurinus was a frequently detected species of the human oral microbial flora, it was not associated with periodontal disease. Further investigations are required to determine whether S. tigurinus is a commensal or an opportunistic oral pathogen with a potential for development of invasive infections.
authors.forename: Andrea
authors.initials: A
authors.lastname: Zbinden
authors.forename: Fatma
authors.initials: F
authors.lastname: Aras
authors.forename: Reinhard
authors.initials: R
authors.lastname: Zbinden
authors.forename: Forouhar
authors.initials: F
authors.lastname: Mouttet
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Schmidlin
authors.forename: Guido V
authors.initials: GV
authors.lastname: Bloemberg
authors.forename: Nagihan
authors.initials: N
authors.lastname: Bostanci
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D008969:Molecular Sequence Data; D009055:Mouth / Q000382:microbiology*; D010510:Periodontal Diseases / Q000382:microbiology; D011446:Prospective Studies; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013291:Streptococcus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S