The human oral microbiome is a complex microbial
community constantly influenced by several external factors such as diet, oral hygiene,
lifestyle and antibiotic exposures, to name a few. Hence it may be expected that subjects with different
geographical, socioeconomic or ethnic backgrounds will have different oral
microbial community structures. Recent studies using next generation sequencing (NGS) have almost
exclusively focused on the oral microbiota of individuals from North America or
Europe, who have ‘good’ oral health, or common oral diseases such as
periodontitis or caries. Very few
studies have been done on subjects of Asian lineage. Among Chinese communities, oral diseases such as
periodontitis are relatively prevalent; hence it is important to elucidate their
oral microbial communities, to identify putative differences. To address this,
we analyzed the subgingival plaque of subjects with periodontitis versus periodontitis-free
controls using 454 pyrosequencing; targeting hypervariable regions of the 16S rRNA
for Eubacteria and Archaea, and the 18S rRNA for the Eukarya. Analysis of the pyrosequencing data revealed
that Actinobacteria, Bacteriodetes, Firmicutes, Fusobacteria, Proterobacteria
and Spirochaetes were the common phyla recovered from both the periodontitis
and periodontitis-free subjects, although in different proportions. Firmicutes was the most abundant phylum
recovered from periodontitis-free subjects followed by Actinobacteria. As for
the periodontitis subjects, Bacteriodetes was predominant, with the majority of
sequences recovered corresponding to Porphyromonas.
Furthermore, levels of the genus Treponema were also significantly higher
in periodontitis subjects. Only sparse
fungi sequences were recovered and Saccharomycetes was more in number among the
periodontitis-free subjects. Lastly, Archaea
was only evident in the periodontitis subjects and 100% of the sequences
recovered were highly similar to Methanobrevibacter
oralis. This study gives an overview
of the diversity of the three domains of life in the oral micro-niche.