Frequent detection of Streptococcus tigurinus in the human oral microbial flora by a specific 16S rRNA gene real-time TaqMan PCR.

Andrea Zbinden,Guido V Bloemberg,Fatma Aras,Nagihan Bostanci,Forouhar Mouttet,Reinhard Zbinden,Patrick R Schmidlin

doi:10.1186/s12866-014-0231-5

Andrea Zbinden, Guido V Bloemberg + Show 5 more

Open Access

https://doi.org/10.1186/s12866-014-0231-5

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Journal: BMC microbiology	Publication Date: Aug 24, 2014
Citations: 41	License type: CC BY 4.0

Affiliation: University of Zurich

Abstract

BackgroundMany 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.ResultsWe 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.ConclusionAlthough 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.

Highlights

Many bacteria causing systemic invasive infections originate from the oral cavity by entering the bloodstream
This pathogenic association between the oral cavity and other parts of the human body is potentially triggered by oral bacteria entering the bloodstream, which increases the risk for invasive infections such as infective endocarditis [10]
All S. tigurinus samples including S. tigurinus strain AZ_4a were detected due to the incorporation of two probes Sti3 and Sti4, respectively. Related species such as S. pneumoniae, S. mitis, S. oralis, S. pseudopneumoniae and S. infantis were not detected by the S. tigurinus specific RT-PCR, as well as other more distantly related species, i.e., S. gordonii, S. sanguinis, S. parasanguinis, S. salivarius, S. anginosus, S. mutans and S. dysgalactiae, showing the specificity of the assay

Summary

Introduction

Many bacteria causing systemic invasive infections originate from the oral cavity by entering the bloodstream. A novel pathogenic bacterium, Streptococcus tigurinus, was identified as causative agent of infective endocarditis, spondylodiscitis and meningitis. Significant associations have been elucidated between periodontitis and other very common systemic diseases, including diabetes mellitus [8] and cardiovascular diseases [9]. This pathogenic association between the oral cavity and other parts of the human body is potentially triggered by oral bacteria entering the bloodstream, which increases the risk for invasive infections such as infective endocarditis [10]. It has been shown to be highly virulent in experimental animal models [14]

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