Pathway between oral bacteria, Parkinson’s disease identified

Dec 11, 2025 | Clinical

The oral bacteria Streptococcus mutans could be associated with Parkinson’s disease, according to a news report from Oral Health.

In a study published in Nature Communications, researchers examined the stool samples of nearly 750 patients with or without Parkinson’s disease.

The researchers found that patients with Parkinson’s disease had S. mutans in their gut microbiomes. They noted that the bacteria are capable of producing the enzyme urocanate reductase that in turn forms the metabolite imidazole propionate, which then damages midbrain dopaminergic neurons and induces neurodegeneration.

After exposing mice to urocanate reductase-producing bacteria, the researchers uncovered neurologic symptoms resembling Parkinson’s disease such as dopaminergic neuronal loss, astrogliosis, microgliosis and motor impairment.

The findings suggested that imidazole propionate could be a pathologic mediator in Parkinson’s disease and highlighted the need for further studies exploring the role of oral bacteria in the gut-brain axis.

Read more: Oral Health