Opening the door to a stable subgingival microbiota

Abstract

Certain phylotypes belonging the Treponema genus and Synergistetes phylum are commonly encountered within anaerobic niches in human and animal hosts; e.g. in subgingival dental plaque, animal rumen and insect guts. However, the respective similarities and differences in phylotype composition within these diverse niches is poorly understood. To address this issue, we analyzed the subgingival microbiota of two horses using both 454 pyrosequencing and clone library-based approaches. Analysis of the (V4-V6) pyrosequencing data revealed that Proteobacteria, Firmicutes and Bacteroidetes were predominant within both subgingival plaque samples; constituting ca. 90% of total reads, although in differencing proportions. Synergistetes and Spirochaetes taxa constituted only ca. 0.1-0.4% of the pyrosequencing reads. There was good correlation between the pyrosequencing and 16S rRNA clone-library data. The vast majority of the spirochete taxa present belonged to seven of the 10 human oral treponeme phylogroups; especially phylogroups 1, 2, 3, 4 and 6. One Spirochaeta phylotype was identified. The majority of the Synergistetes phylotypes corresponded to Oral clusters A and B. However, taxa closely related to Synergistes joensii were also present. Considered holistically, the subgingival microbiota present within these two horses shared high levels of similarity with that typically found within healthy human periodontal sites.