Oral microbiome profiles of gingivitis and periodontitis by next-generation sequencing among a group of hospital patients in Korea: A cross-sectional study

Objectives: The oral microbiome plays an important role in the development and progression of periodontal disease. The purpose of this study was to compare microbial profiles of oral cavities in good health, with gingivitis, and in a state of periodontitis, and to identify novel pathogens involved in periodontal diseases. Methods: One hundred and two participants, including 33 healthy controls, 41 patients with gingivitis, and 28 patients with periodontitis, were included in this cross-sectional study. Salivary oral microbiomes were investigated using 16S rRNA metagenomic sequencing, and the microbial profiles of each group were compared using age- and sex-adjusted general linear models. Results: The abundance of amplicon sequence variants and Chao1 diversity were significantly elevated in the gingivitis and periodontitis groups relative to healthy controls (p = 0.046). Based on linear discriminant analysis (LDA) scores (>2), Tenericutes, Mollicutes, Mycoplasmatales, Mycoplasmataceae, Mycoplasma, Bacteroidaceae, and Phocaeicola were significantly enriched in the gingivitis group, and Synergistetes, Synergistia, Synergistales, Synergistaceae, Fretibacterium, Sinanaerobacter, and Filifactor were enriched in the periodontitis group. The relative abundances of Fretibacterium fastidiosum, Sinanaerobacter chloroacetimidivorans, and Filifactor alocis (q = 0.008, all bacteria) were highest in the periodontitis group and lowest in the control group. The relative abundance of Treponema denticola was significantly elevated in the periodontitis group compared to the other two groups (q = 0.024). Conclusions: Oral microbiomes differed between groups. T. denticola, F. fastidiosum, S. chloroacetimidivorans and F. alocis were significantly more abundant in the periodontitis group than in the control group. Additionally, the abundance of T. denticola and F. fastidiosum in the periodontitis group was significantly different from that in the gingivitis group.