Distributions of Synergistetes Bacteria Within Diseased and Asymptomatic Periodontal Niches

Abstract

Objective To survey the diversity and distributions of Synergistetes taxa, within diseased and asymptomatic periodontal and peri-implant sites, within a cohort of subjects with both periodontitis and peri-implantitis lesions. Methods Four single-site samples of subgingival/submucosal plaque were collected from Chinese subjects (n=18; 9 male/9 female), recruited with informed consent (previously described by Zhuang et al., Clinical Oral Implants Research 2014, doi: 10.1111/clr.12508). Plaque was sampled (using paper points) from one healthy gingival site (HT); one periodontitis site (PPD≥4mm; DT); one healthy peri-implant site (HI); and one peri-implantitis site with PPD≥5mm, presence of BOP, and radiographic bone loss (DI). PCR primer sets were used to selectively PCR-amplify ca. 650 bp regions of the 16S rRNA gene from oral cluster A and B Synergistetes, respectively, from DNA purified from each sample (n=72). Plasmid clone libraries of PCR amplicons were constructed, and ca. 50-60 clones were sequenced for each positive sample. Sequence data was analyzed using various bioinformatic, phylogenetic and statistical approaches. Results 21/72 single-site samples (from 12/18 subjects) yielded Synergistetes 16S rRNA PCR products: HT (n=6), DT (n=6), HI (n=2), DI (n=6). Clone libraries were successfully constructed for these 21 samples, yielding a total of 1,338 quality-filtered 16S rRNA sequences. Sequences were assigned to Synergiststes operational taxonomic units (OTUs, using 98.5% identity cut-off). 20 oral cluster A OTUs and 1 oral cluster B OTU (OTU-004=Pyramidobacter piscolens) were identified. Three OTUs predominated, including Fretibacterium fastidiosum (OTU-003). Neither the prevalence nor clonal abundances of Synergistetes exhibited significant differences between the 4 clinical sites. The numbers of F. fastidiosum clones were positively correlated to gingival index, BOP and levels of bone resorption. Conclusions Diverse Synergistetes taxa were widely distributed across diseased and asymptomatic periodontal and peri-implant sites, in subjects with both periodontitis and peri-implantitis. Fretibacterium fastidiosum levels were correlated with disease-related clinical parameters. Support Funding Agency/Grant Number: Research Grants Council (RGC) of Hong Kong, General Research Fund (#780713) Financial Interest Disclosure: none