Supragingival Plaque Microbiomes in a Diverse South Florida Population

Abstract

Trillions of microbes comprise the human oral cavity, collectively acting as another bodily organ. Although research is several decades into the field, there is no consensus on how oral microbiomes differ in underrepresented groups such as Hispanic, Black, and Asian populations living in the United States. Here, using 16S ribosomal RNA sequencing, we examine the bacterial ecology of supragingival plaque from four quadrants of the mouth along with a tongue swab from 26 healthy volunteers from South Florida (131 total sequences after filtering). As an area known to be a unique amalgamation of diverse cultures from across the globe, South Florida allows us to address the question of how supragingival plaque microbes differ across ethnic groups, thus potentially impacting treatment regiments related to oral issues. We assess overall phylogenetic abundance, alpha and beta diversity, and linear discriminate analysis of participants based on sex, ethnicity, sampling location in the mouth, and gingival health. Within this cohort, we find the presence of common phyla such as Firmicutes and common genera such as Streptococcus. Additionally, we find significant differences across sampling locations, sex, and gingival health. This research stresses the need for the continued incorporation of diverse populations within human oral microbiome studies.

Keywords: 16S rRNA gene sequencing; dental bacteria; human microbiota; next generation sequencing; oral health; oral microbiomes; periodontal disease; supragingival plaque.

Figure 1

Bar graph reflecting the phyla abundance across all samples. The abundance shown here includes the top 100 most common OTUs after samples were first rarefied to 10,000 reads.

Figure 2

Bar graph reflecting the genus abundance across all samples. The abundance shown here includes the top 100 most common OTUs after samples were first rarefied to 10,000 reads.

Figure 3

Alpha diversity bar plot reflecting the total observed unique OTUs across each of the five sampling locations (LL—lower left, LR—lower right, T—tongue, UL—upper left, UR—upper right). Significance values were documented (* p < 0.05; ** p < 0.01; *** p < 0.001) and all samples were rarefied to 10,000 reads.

Figure 4

Alpha diversity bar plot reflecting the total observed unique OTUs across each sex (M—male, F—female). The results between the two sexes were significant (at the * p < 0.05 level) and all samples were rarefied to 10,000 reads.

Figure 5

Beta diversity plot reflecting weighted Bray–Curtis principal coordinate analyses involving samples rarefied to 10,000 reads. Each point is associated with a single sample, with the shape indicating ethnicity and the color indicating sampling location (LL—lower left, LR—lower right, T—tongue, UL—upper left, UR—upper right).

Figure 6

LefSe analysis showing the enriched groups of bacterial genera associated with the three periodontal health statuses: (A) generalized gingivitis and a periodontally healthy oral cavity, (B) localized gingivitis and a periodontally healthy oral cavity, and (C) generalized gingivitis and localized gingivitis.