Researchers from Japan have discovered a potential connection between a common mouth and gut bacteria, Streptococcus anginosus, and increased stroke risk. The study, to be presented at the American Stroke Association's International Stroke Conference 2025, provides preliminary evidence that this bacterial strain could be a significant indicator of stroke outcomes.
The research, conducted at Japan's largest stroke center, analyzed oral and gut bacteria in 250 participants, comparing 200 stroke patients with 50 non-stroke individuals. Scientists found that Streptococcus anginosus was significantly more abundant in stroke patients' saliva and gut samples.
Key findings revealed that Streptococcus anginosus in the gut was independently associated with 20% higher odds of stroke after controlling for vascular risk factors. Moreover, stroke survivors with this bacteria experienced a significantly higher risk of death and major cardiovascular events during a two-year follow-up period.
Lead researcher Dr. Shuichi Tonomura suggested that future diagnostic approaches might include quick tests to detect harmful bacteria, potentially helping calculate stroke risk. The study also highlighted the importance of maintaining good oral hygiene and reducing sugar intake to prevent tooth decay-causing bacteria.
However, researchers caution that the study's limitations include its small sample size and focus on a Japanese population, which may limit generalizability to other demographic groups. Further research is needed to understand the broader implications of bacterial interactions and stroke risk.
The findings underscore the complex relationship between oral microbiota and cardiovascular health, suggesting that bacterial composition could become a valuable tool in stroke prevention strategies.
