Background: Halitosis is caused by metabolites produced by oral microorganisms. Hydrogen sulfide is the most important compound that leads to the oral malodor, and is thought to be closely correlated with the activity of oral microorganism. Therefore, it is important to clarify the correlation between oral microbes and metabolites. Methods: Based on the 16S rRNA gene amplicon and shotgun metagenomic sequencing of oral microorganism, and oral malodor test, this study attempted to explain the contribution of oral microorganisms to the hydrogen sulfide of oral malodor.
Results: The data shows that microbial taxa consisted in the H2S low and high groups are different, and most of the enriched taxa in the H2S high group are genus that correlated with H2S concentration. The two species Fusobaeterium periodonticum and Prevotella nanceiensis are significant different in both coverage breadth and depth and LPS biosynthesis contributions in two groups. According to KEGG metabolism pathways detected by HUMAnN2, subjects of the H2S high group may have a high risk to bacterial infection, since the LPS biosynthesis is enrichment. The contribution of F. periodonticum to sulfur metabolism between two groups is significantly different, and the relative abundance of F. periodonticum is higher in the H2S high group as well.
Conclusions: The H2S content, is significantly associated with the composition and abundance of microorganisms in the oral cavity. The increase of microbial abundance and metabolism of some sulfide products are the main causes of halitosis. The most of the enriched microorganisms enriched in people with high H2S are associated with oral diseases such as caries and periodontal diseases, indicating that the diseases associated with oral microbes are not independent of each other and have some associations between some oral diseases.