An interaction between two common oral bacteria may result in the formation of a powerful chemical compound closely linked to the development of bad breath and gum disease, according to a study.
A metabolite produced by the oral microorganism Streptococcus gordonii (S. gordonii) triggers the bacterial species Fusobacterium nucleatum (F. nucleatum) to produce methyl mercaptan (CH3SH), a compound that is a major cause of bad breath.
“Identifying the mechanisms involved in CH3SH production is expected to lead to the development of new strategies to combat halitosis,” write the authors, led by Takeshi Hara of the Department of Naval Architecture and Ocean Sciences at Osaka University. in Japan.
To better understand how certain bacteria interact to cause bad breath, researchers developed a large-scale anaerobic co-culture system to study interactions between different oral bacteria, testing both direct physical contact and long-term effects such as chemical secretion.
The team selected Actinomyces naeslundii (A.naeslundii), S.gordonii (early colonizers), F. nucleatum and Prevotella intermedia (P.intermedia) (middle colonizers), and Fusobacterium alocis ( F.alocis) and Porphyromonas gingivalis (P.gingivalis) (late colonizers).
Using stable isotope tracers and gene expression analysis, they found that S. gordonii releases ornithine, an amino acid produced in the body, and stimulates F. nucleatum to produce more polyamine, a compound that regulates cellular and genetic functions. This in turn triggered the F. nucleatum methionine recycling pathway, a process that converts sulfur-containing metabolites into methionine, leading to increased production of CH3SH, the authors write.
It should be noted that the study had no limitations.
Because oral bacteria exchange various metabolites, further research is needed to comprehensively understand the significance of the microbial metabolic interactions that lead to the development of halitosis.
“Metabolic interactions may modulate the release of volatile compounds by microorganisms, thereby potentially contributing to the development of halitosis,” write Hara et al.