title: Bacterial community composition of chronic periodontitis and novel oral sampling sites for detecting disease indicators.
abstract: BACKGROUND
  Periodontitis is an infectious and inflammatory disease of polymicrobial etiology that can lead to the destruction of bones and tissues that support the teeth. The management of chronic periodontitis (CP) relies heavily on elimination or at least control of known pathogenic consortia associated with the disease. Until now, microbial plaque obtained from the subgingival (SubG) sites has been the primary focus for bacterial community analysis using deep sequencing. In addition to the use of SubG plaque, here, we investigated whether plaque obtained from supragingival (SupG) and tongue dorsum sites can serve as alternatives for monitoring CP-associated bacterial biomarkers.
  
  
  RESULTS
  Using SubG, SupG, and tongue plaque DNA from 11 healthy and 13 diseased subjects, we sequenced V3 regions (approximately 200 bases) of the 16S rRNA gene using Illumina sequencing. After quality filtering, approximately 4.1 million sequences were collapsed into operational taxonomic units (OTUs; sequence identity cutoff of >97%) that were classified to a total of 19 phyla spanning 114 genera. Bacterial community diversity and overall composition was not affected by health or disease, and multiresponse permutation procedure (MRPP) on Bray-Curtis distance measures only supported weakly distinct bacterial communities in SubG and tongue plaque depending on health or disease status (P < 0.05). Nonetheless, in SubG and tongue sites, the relative abundance of Firmicutes was increased significantly from health to disease and members of Synergistetes were found in higher abundance across all sites in disease. Taxa indicative of CP were identified in all three locations (for example, Treponema denticola, Porphyromonas gingivalis, Synergistes oral taxa 362 and 363).
  
  
  CONCLUSIONS
  For the first time, this study demonstrates that SupG and tongue dorsum plaque can serve as alternative sources for detecting and enumerating known and novel bacterial biomarkers of CP. This finding is clinically important because, in contrast with SubG sampling that requires trained professionals, obtaining plaque from SupG and tongue sites is convenient and minimally-invasive and offers a novel means to track CP-biomarker organisms during treatment outcome monitoring.
authors.affiliation: Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, ON M51G6, Canada.
authors.forename: Vaia
authors.initials: V
authors.lastname: Galimanas
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Michael William
authors.initials: MW
authors.lastname: Hall
authors.affiliation: Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, ON M51G6, Canada.
authors.forename: Natasha
authors.initials: N
authors.lastname: Singh
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Michael David Joseph
authors.initials: MD
authors.lastname: Lynch
authors.affiliation: Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, ON M51G6, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Goldberg
authors.affiliation: Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, ON M51G6, Canada.
authors.forename: Howard
authors.initials: H
authors.lastname: Tenenbaum
authors.affiliation: Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, ON M51G6, Canada.
authors.forename: Dennis Gerard
authors.initials: DG
authors.lastname: Cvitkovitch
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Josh David
authors.initials: JD
authors.lastname: Neufeld
authors.affiliation: Dental Research Institute, University of Toronto, 124 Edward Street, Toronto, ON M51G6, Canada.
authors.forename: Dilani Braziunas
authors.initials: DB
authors.lastname: Senadheera
keywords: 16S rRNA gene; Bacterial community; Chronic periodontitis; Oral microbiome; Plaque; Subgingival; Supragingival; Tongue