AUTHOR=Belstrøm Daniel , Constancias Florentin , Markvart Merete , Sikora Martin , Sørensen Christiane Elisabeth , Givskov Michael 

TITLE=Transcriptional Activity of Predominant Streptococcus Species at Multiple Oral Sites Associate With Periodontal Status

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.752664

DOI=10.3389/fcimb.2021.752664

ISSN=2235-2988

ABSTRACT=<sec><title>Background</title><p><italic>Streptococcus</italic> species are predominant members of the oral microbiota in both health and diseased conditions. The purpose of the present study was to explore if different ecological characteristics, such as oxygen availability and presence of periodontitis, associates with transcriptional activity of predominant members of genus <italic>Streptococcus.</italic> We tested the hypothesis that genetically closely related <italic>Streptococcus</italic> species express different transcriptional activities in samples collected from environments with critically different ecological conditions determined by site and inflammatory status.</p></sec><sec><title>Methods</title><p>Metagenomic and metatranscriptomic data was retrieved from 66 oral samples, subgingival plaque (n=22), tongue scrapings (n=22) and stimulated saliva (n=22) collected from patients with periodontitis (n=11) and orally healthy individuals (n=11). Species-specific transcriptional activity was computed as Log2(RNA/DNA), and transcriptional activity of predominant <italic>Streptococcus</italic> species was compared between multiple samples collected from different sites in the same individual, and between individuals with different oral health status.</p></sec><sec><title>Results</title><p>The predominant <italic>Streptococcus</italic> species were identified with a site-specific colonization pattern of the tongue and the subgingival plaque. A total of 11, 4 and 2 pathways expressed by <italic>S. parasanguinis, S. infantis</italic> and <italic>S. salivarius</italic>, respectively, were recorded with significantly higher transcriptional activity in saliva than in tongue biofilm in healthy individuals. In addition, 18 pathways, including pathways involved in synthesis of peptidoglycan, amino acid biosynthesis, glycolysis and purine nucleotide biosynthesis expressed by <italic>S. parasanguinis</italic> and 3 pathways expressed by <italic>S. salivarius</italic> were identified with significantly less transcriptional activity in patients with periodontitis.</p></sec><sec><title>Conclusion</title><p>Data from the present study significantly demonstrates the association of site-specific ecological conditions and presence of periodontitis with transcriptional activity of the predominant <italic>Streptococcus</italic> species of the oral microbiota. In particular, pathways expressed by <italic>S. parasanguinis</italic> being involved in peptidoglycan, amino acid biosynthesis, glycolysis, and purine nucleotide biosynthesis were identified to be significantly associated with oral site and/or inflammation status.</p></sec>