Oral tongue plaque Metagenome
To probe the microbial basis of halitosis in natural human populations, we em-ployed a longitudinal study design to compare the tongue microbiota associated with halitosis in 29 Chinese adults who underwent a consecutive three-day evaluation for the amount of volatile sulfur compounds (VSC) excreted orally. Three levels of the disease state (healthy, halitosis and severe halitosis) were defined based on the Halimeter value. Community structure of the tongue plaques was more sensitive to changes of disease state than to inter-personal variations or difference in sampling time. Within each subject, the structure of microbiota was relatively stable, while their variations were correlated with the change in Halimeter value. Severe halitosis micro-biota were the most conserved in community structure, whereas the healthy ones were relatively varied. Halitosis-associated bacteria were identified, among which the rela-tive abundance of Leptotrichia and Prevotella was positively correlated with halitosis severity whereas Haemophilus demonstrated a negative relationship with disease. Our study provided one of the first organismal profiles of disease-associated tongue mi-crobiota and revealed microbes that can potentially be used to evaluate halitosis state and progress.