Microbiome profiles in periodontitis in relation to host and disease characteristics

Abstract

Periodontitis is an inflammatory condition that affects the supporting tissues surrounding teeth. The occurrence of periodontitis is associated with shifts in the structure of the communities that inhabit the gingival sulcus. Although great inter-subject variability in the subgingival microbiome has been observed in subjects with periodontitis, it is unclear whether distinct community types exist and if differences in microbial signatures correlate with host characteristics or with the variable clinical presentations of periodontitis. Therefore, in this study we explored the existence of different community types in periodontitis and their relationship with host demographic, medical and disease-related clinical characteristics. Clustering analyses of microbial abundance profiles suggested two types of communities (A and B) existed in the 34 subjects with periodontitis evaluated. Type B communities harbored greater proportions of certain periodontitis-associated taxa, including species historically associated with the disease, such as Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola, and taxa recently linked to periodontitis. In contrast, subjects with type A communities had increased proportions of different periodontitis-associated species, and were also enriched for health-associated species and core taxa (those equally prevalent in health and periodontitis). Periodontitis subgingival clusters were not associated with demographic, medical or disease-specific clinical parameters other than periodontitis extent (proportion of sites affected), which positively correlated with the total proportion of cluster B signature taxa. In conclusion, two types of microbial communities were detected in subjects with periodontitis. Host demographics and underlying medical conditions did not correlate with these profiles, which instead appeared to be related to periodontitis extent, with type B communities present in more widespread disease cases. The two identified periodontitis profiles may represent distinct dysbiotic processes potentially requiring community-tailored therapeutic interventions.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1. Inter-subject variability of subgingival communities in periodontitis and relationship of microbial profiles with demographic, medical and clinical characteristics.

Graph shows a heatmap of the transformed relative abundances for the top 300 OTUs found in the subgingival microbial communities of subjects with periodontitis. Subjects are shown in rows, while OTUs appear in columns. Color scale for heatmap appears in the top left with the most abundant OTUs in yellow and the least abundant in blue. Subject raws are organized according to results of unsupervised hierarchical clustering (complete linkage) of microbial communities based on OTU relative abundances. Dendogram on the left shows a tendency for 2 clusters to form (A and B). Color bars in the right depict the demographic, medical and clinical characteristics for each subject. Color scales for metadata appear on the right side.

Fig 2. Signature OTUs that define periodontitis clusters A and B (hierarchical).

Graph shows OTUs with a statistically significant difference in relative abundance between hierarchical clusters A and B. Bars represent the median and range of relative abundances for each OTU. OTUs increased in Cluster A appear in the top, while OTUs increased in cluster B appear in the bottom. OTUs were labeled according to their association with health or periodontitis considering data from Abusleme et al. [6], Perez-Chaparro et al. [31] and a comparison of our periodontitis samples with HMP healthy subjects (S4 Fig). Taxa were classified as P (periodontitis), H (health) and C (core species), according to at least one study. If a disagreement existed between studies, taxa were labeled under more than one category.