Diversity of Treponema and Synergistetes phylotypes in equine subgingival plaque

Abstract

Objectives: To use a 16S rRNA-based molecular approach investigate the composition of bacterial phylotypes belonging to the Spirochaetes and Synergistetes phyla present in equine subgingival plaque Methods: Pooled subgingival plaque samples were collected from multiple sites from two recently euthanized adult horses (EQ1, EQ2) with apparently good oral and periodontal health. Bacterial DNA was purified and 16S rRNA genes were amplified using the TPU1 and C90 ‘spirochete selective’ primers. After cloning into TOPO plasmids, inserts from ca. 100 plasmids from each horse were sequenced bidirectionally. After removal of chimeras and poor quality reads, a variety of bioinformatic and computational phylogenetic approaches were used to analyze the ca. 1500bp 16S rRNA sequence datasets obtained.

Results: 95 and 103 near full-length 16S rRNA sequences were obtained from EQ1 and EQ2, respectively; corresponding to a total of 180 unique sequences and 88 unique phylotypes (99% sequence identity cut-off). Taxa belonging to the Actinobacteria, Firmicutes, Fusobacteria, Proteobacteria, Spirochaetes and Synergistetes phyla were identified. Phylotypes present in EQ1: Spirochaetes (n=7); Synergistetes (n=14). EQ2 phylotypes: Spirochaetes (n=16), Synergistetes (n=2). All Spirochaetes taxa belonged to the genus Treponema, which corresponded to 7 of the 10 human oral treponeme phylogroups. Synergistetes taxa corresponding to oral clusters A and B were identified.

Conclusions: Data obtained from this snapshot of equine subgingival microbiota revealed that bacterial taxa belonging to the Synergistetes and Sprirochaetes phyla were very similar to those detected within equivalent healthy niches in humans.

Student Presenter This abstract is based on research that was funded entirely or partially by an outside source: General Research Fund of the Research Grants Council of Hong Kong [#781911]