On the ecosystemic network of saliva in healthy young adults

Abstract

A dysbiotic state is believed to be a key factor in the onset of oral disease. Although oral diseases have been studied for decades, our understanding of oral health, the boundaries of a healthy oral ecosystem and ecological shift toward dysbiosis is still limited. Here, we present the ecobiological heterogeneity of the salivary ecosystem and relations between the salivary microbiome, salivary metabolome and host-related biochemical salivary parameters in 268 healthy adults after overnight fasting. Gender-specific differences in the microbiome and metabolome were observed and were associated with salivary pH and dietary protein intake. Our analysis grouped the individuals into five microbiome and four metabolome-based clusters that significantly related to biochemical parameters of saliva. Low salivary pH and high lysozyme activity were associated with high proportions of streptococcal phylotypes and increased membrane-lipid degradation products. Samples with high salivary pH displayed increased chitinase activity, higher abundance of Veillonella and Prevotella species and higher levels of amino acid fermentation products, suggesting proteolytic adaptation. An over-specialization toward either a proteolytic or a saccharolytic ecotype may indicate a shift toward a dysbiotic state. Their prognostic value and the degree to which these ecotypes are related to increased disease risk remains to be determined.

Characterization of oral microbiota and acetaldehyde production

“…had fewer teeth with dental caries, were non-smokers, and other such factors) and had a lower risk for pneumonia-related death [20,26], suggesting that the predominance of N. flavescens, F. periodonticum , and P. pasteri is an indicator of healthy oral microbiota. Furthermore, a recent report by Zaura et al suggested that a bacterial community type characterized by a predominance of N. flavescens and Neisseria subflava positioned away from dysbiosis [27]. However, it is unexpected that a salivary microbiota predominant with Neisseria species is beneficial for health despite their capacity for high ACH production ability.…”

The salivary microbiota in health and disease

“…An elegant example of such an approach was recently published in a study showing that analysis of S. mutans in saliva based on adhesion subtypes could be used for future caries risk prediction [92]. It is also interesting that in a recent cross-sectional study from 2017 data showed that orally healthy individuals can be divided into five ecotypes based on characteristics of SM, the salivary metabolome and host-related biochemical salivary parameters [93]. In addition, a recent longitudinal study in hospitalized cancer patients demonstrated that increased variability of SM was associated with adverse clinical outcomes [94].…”

Salivary Metabolomics: From Diagnostic Biomarker Discovery to Investigating Biological Function

“…At present, very few studies have studied saliva using both sequencing and metabolomics technologies. The most comprehensive study of this type has made steps in elucidating the relationships between salivary metabolites and associated microbial species [145]. There is a clear need for future work to reconcile the functional information provided by metabolomics with the oral microbial composition and host factors that may modify the latter.…”