Oral cavity contains distinct niches with dynamic microbial communities

Abstract

Microbes colonize human oral surfaces within hours after delivery. During postnatal development, physiological changes, such as the eruption of primary teeth and replacement of the primary dentition with permanent dentition, greatly alter the microbial habitats, which, in return, may lead to community composition shifts at different phases in people's lives. By profiling saliva, supragingival and mucosal plaque samples from healthy volunteers at different ages and dentition stages, we observed that the oral cavity is a highly heterogeneous ecological system containing distinct niches with significantly different microbial communities. More importantly, the phylogenetic microbial structure varies with ageing. In addition, only a few taxa were present across the whole populations, indicating a core oral microbiome should be defined based on age and oral niches.

Cigarette smoking and the oral microbiome in a large study of American adults

“…This study was limited by lack of metagenomic data to determine the actual gene content of bacteria altered by smoking and lack of longitudinal samples pre-and post-smoking cessation. Additionally, due to the elderly age of our study participants, our findings may not be generalizable to younger populations, particularly since the oral microbiome changes with age (Xu et al, 2015). Future studies should investigate the impact of smoking on the metagenomic content of the oral microbiome, and whether smoking-related oral bacterial and/or metagenomic changes mediate the health effects of smoking.…”

Acid-resistant genes of oral plaque microbiome from the functional metagenomics

“…The two acid-resistant genes obtained in this study were aligned with sequences from two common cariogenic genera, Actinomyces and Haemophilus [30], which represent two of seven dominant cariogenic phyla (Actinobacteria and Proteobacteria) [31]. Bioinformatics analysis found that the ORF in pSL-2–41 encodes two domains (the malic and Malic_M domains) that form the N-terminal region of the malate dehydrogenase protein, but the acid-resistance assay indicated that this fragment is sufficient to allow E. coli to survive in this hostile environment.…”

Fungi at the Scene of the Crime: Innocent Bystanders or Accomplices in Oral Infections?

“…Within recent years, there has been a number of studies concerned with the compositional makeup of the oral microbiome, which varies dramatically between health and various diseases, as well as distinct ecological niches [4, 21, 22•]. The heterogeneity and diversity between niches observed within the oral microbiome is in part due to the numerous surfaces that exist within the oral cavity [4]. Microbiome studies in oral disease have demonstrated the existence of distinct microbial communities compared to health.…”

“…This almost 150-fold difference in the occupancy of available space upon orally relevant surfaces for fungi suggests that it is at least a bystander, but whether innocent or not remains to be determined. The oral cavity contains numerous different micro-environments, ranging from enamel, mucosa, periodontal pockets, acrylic and metal substrates, and dentine, that are inhabited by tens to hundreds of bacterial species [4]. Polymicrobial communities are able to form biofilms upon this vast variety of substrates [5••, 6, 7].…”