%0 Journal Article
%T Multilocus sequence analysis of Treponema denticola strains of diverse origin
%A Mo Sisu
%A You Meng
%A Su Yvonne CF
%A Lacap-Bugler Donnabella C
%J BMC Microbiology
%D 2013
%I BioMed Central
%R 10.1186/1471-2180-13-24
%X Background The oral spirochete bacterium Treponema denticola is associated with both the incidence and severity of periodontal disease. Although the biological or phenotypic properties of a significant number of T. denticola isolates have been reported in the literature, their genetic diversity or phylogeny has never been systematically investigated. Here, we describe a multilocus sequence analysis (MLSA) of 20 of the most highly studied reference strains and clinical isolates of T. denticola; which were originally isolated from subgingival plaque samples taken from subjects from China, Japan, the Netherlands, Canada and the USA. Results The sequences of the 16S ribosomal RNA gene, and 7 conserved protein-encoding genes (flaA, recA, pyrH, ppnK, dnaN, era and radC) were successfully determined for each strain. Sequence data was analyzed using a variety of bioinformatic and phylogenetic software tools. We found no evidence of positive selection or DNA recombination within the protein-encoding genes, where levels of intraspecific sequence polymorphism varied from 18.8% (flaA) to 8.9% (dnaN). Phylogenetic analysis of the concatenated protein-encoding gene sequence data (ca. 6,513 nucleotides for each strain) using Bayesian and maximum likelihood approaches indicated that the T. denticola strains were monophyletic, and formed 6 well-defined clades. All analyzed T. denticola strains appeared to have a genetic origin distinct from that of ¡®Treponema vincentii¡¯ or Treponema pallidum. No specific geographical relationships could be established; but several strains isolated from different continents appear to be closely related at the genetic level. Conclusions Our analyses indicate that previous biological and biophysical investigations have predominantly focused on a subset of T. denticola strains with a relatively narrow range of genetic diversity. Our methodology and results establish a genetic framework for the discrimination and phylogenetic analysis of T. denticola isolates, which will greatly assist future biological and epidemiological investigations involving this putative ¡®periodontopathogen¡¯.
%K Treponema denticola
%K Periodontal disease
%K Phylogeny
%K Multilocus sequence analysis
%K MLSA
%K Spirochete
%K Oral microbiota
%K Infectious diseases
%K Dentistry
%U http://www.biomedcentral.com/1471-2180/13/24