Measuring the subgingival microbiota in periodontitis patients: Comparison of the surface layer and the underlying layers

Abstract

Periodontitis is a major cause of tooth loss in adults that initially results from dental plaque. Subgingival plaque pathogenesis is affected by both community composition and plaque structures, although limited data are available concerning the latter. To bridge this knowledge gap, subgingival plaques were obtained using filter paper (the fourth layer) and curette (the first-third layers) sequentially and the phylogenetic differences between the first-third layers and the fourth layer were characterized by sequencing the V3-V4 regions of 16S rRNA. A total of 11 phyla, 148 genera, and 308 species were obtained by bioinformatic analysis, and no significant differences between the operational taxonomic unit numbers were observed for these groups. In both groups, the most abundant species were Porphyromonas gingivalis and Fusobacterium nucleatum. Actinomyces naeslundii, Streptococcus intermedius, and Prevotella intermedia possessed relatively high proportions in the first-third layers; while in the fourth layer, both traditional pathogens (Treponema denticola and Campylobacter rectus) and novel pathobionts (Eubacterium saphenum, Filifactor alocis, Treponema sp. HOT238) were prominent. Network analysis showed that either of them exhibited a scale-free property and was constructed by two negatively correlated components (the pathogen component and the nonpathogen component), while the synergy in the nonpathogen component was lower in the first-third layers than that in the fourth layer. After merging these two parts into a whole plaque group, the negative/positive correlation ratio increased. With potential connections, the first-third layers and the fourth layer showed characteristic key nodes in bacterial networks. K E Y W O R D Speriodontitis, plaque layers, sequencing, subgingival microbiota Abbreviations: ANCOVA, analysis of covariance; ANOSIM, analysis of the similarities; BI, bleeding index; CAL, clinical attachment loss; FISH, fluorescent in situ hybridization; LDA, linear discriminant analysis; LEfSe, linear discriminant analysis effect size; OTU, operational taxonomic unit; PCoA, principal coordinate analysis; PD, probing depth; PlI, plaque index.

Structure and Function of Oral Microbial Community in Periodontitis Based on Integrated Data

“…Furthermore, we described the variation of microbial composition in different PPDs. Our results showed that some pathobionts were consistent with those reported in previous studies (Kirst et al, 2015;Liu et al, 2020) and supported the finding that periodontal dysbiosis was not due to specific microorganisms, rather due to the increasing level of pathobionts. The two reasons for this are likely that (1) microbial community dysbiosis leads to periodontal disease, and (2) periodontitis is caused by some specific pathogenic bacteria that have not yet been identified.…”

“…The datasets from nine publications (Griffen et al, 2012;Galimanas et al, 2014;Bizzarro et al, 2016;Califf et al, 2017;Chen et al, 2018;Peŕez-Chaparro et al, 2018;Wei et al, 2019;Liu et al, 2020;Shi et al, 2020) were divided into two groups-periodontal disease (PD) and healthy control (HC)-according to our predetermined criteria. The mean age of the HC group was 34.4 ± 7.1 years, and the mean age of the PD group was 43.7 ± 8.2 years.…”

Periodontal Pathogens’ strategies disarm neutrophils to promote dysregulated inflammation

“…found (Liu et al, 2020;Schlafer et al, 2010). Thus, F. alocis is strongly associated with periodontitis as a key player in biofilm formation (Aruni et al, 2011;Chen et al, 2015;Naginyte et al, 2019;Wang et al, 2013).…”

“…While there is a high incidence of F. alocis in periodontitis patients, there is a complete absence or low number detected in healthy patients, designating F. alocis as a crucial marker for periodontitis along with P. gingivalis , T. denticola, and T. forsythia (Ahmed et al., 2009; Deng et al., 2017; Ikeda et al., 2019; Kumar et al., 2003, 2006; Schlafer et al., 2010; Schulz et al., 2019). In the oral cavity, F. alocis forms biofilms in close proximity to the soft tissue where some traditional pathogens like T. denticola are also found (Liu et al., 2020; Schlafer et al., 2010). Thus, F. alocis is strongly associated with periodontitis as a key player in biofilm formation (Aruni et al., 2011; Chen et al., 2015; Naginyte et al., 2019; Wang et al., 2013).…”

The Nexus Between Periodontal Inflammation and Dysbiosis

“…In this context, it is significant that the periodontal pathogens Porphyromonas gingivalis and Treponema denticola are predominantly located in deep periodontal pockets at depths of more than 4 mm (52). Furthermore, these pathogens are found together with other periodontal pathogens in microcolony blooms in the biofilm surface layer adjacent to the epithelial lining at the base of deep pockets (52)(53)(54)(55)(56). This positioning and colocalization would advantage them in terms of release of outer membrane vesicles loaded with virulence factors into the subjacent tissue and access to the exudate from that inflamed tissue as well as being consistent with the established mutualistic symbiosis and pathogenesis displayed by these species (55,(57)(58)(59).…”