Oral bacteria linked to the risk of stroke

Summary: A new study reveals that bacteria Streptococcus Anginosus is more abundant in the saliva and intestine of people who have had a stroke and are associated with a higher risk of death and major cardiovascular events. The researchers compared 189 patients with stroke with 55 non -time participants, noting that this bacteria increased the risk of stroke by 20%.

Meanwhile, beneficial bacteria like Anaerostipes Hadrus And Bacteroides Plebeius were linked to a reduction in the risk of stroke. The results highlight the importance of oral hygiene in stroke prevention, as Streptococcus Anginosus contributes to dental caries.

Key facts:

• Risk factor for stroke: Streptococcus Anginosus was linked to a risk of 20% higher and lower results.
• Protective bacteria: Anaerostipes Hadrus And Bacteroides Plebeius were associated with a reduction in the risk of stroke.
• Oral health connection: Poor oral hygiene can contribute to inflammation, increasing stroke sensitivity.

Source: Aha

A current bacteria generally found in the mouth and gastrointestinal tracks, Streptococcus pseudonymCan be abundant in the guts of people with a stroke and is associated with a worse prognosis and an increased risk of death, according to a preliminary study to present at the International Conference of the AVCA 2025 of the American Stroche Association .

The meeting is in Los Angeles, from February 5 to 7, 2025 and is a global meeting for researchers and clinicians dedicated to the science of strokes and brain health.

“In the future, if there was a quick test to detect harmful bacteria in the mouth and the intestine, we could use information to calculate the risk of stroke.

“The targeting of these specific harmful oral bacteria can help prevent cerebral vascular accidents,” said Shuichi Tonomura, MD, principal author of the study doctor and staff in the neurology department of the National Cerebral and Cardiovascular Center in Osaka, in Japan.

Everyone has thousands of bacteria in their intestine, collectively known as the intestinal microbiota. There is also another community of bacteria in the mouth called oral microbiota.

“Most of these bacteria positively affect the body and help with normal body processes, such as digestion. However, when the types of useful and unnecessary bacteria are unbalanced, a disease can occur, noted Tonomura.

Previously, these researchers have discovered that a different bacteria that causes dental caries, Streptococcus mutanswas associated with a higher risk of bleeding inside the brain.

In this new study, conducted in the largest stroke center in Japan, researchers quantified all detectable bacteria both in saliva and in the intestines People who had recently had any type of stroke, comparing them to people without a vascular accident of similar age with routine medical examinations.

Researchers have discovered that a species of bacteria, Streptococcus Anginosus, was significantly more abundant in the saliva and intestine of people with an acute stroke than in the witness group of people who had not had a stroke.

An analysis of various groups of bacteria revealed:

• Streptococcus Anginosus in the intestine was independently associated with chances of 20% higher stroke after having controlled the vascular risk factors, while Anaerostipes Hadrus (a intestinal bacteria associated with beneficial effects) was associated with a drop in risk of 18% and bacteroides plebeius (A common intestinal bacteria in the Japanese population) was associated with a drop in risk of 14%.
• During the two -year follow -up, the survivors of a stroke with Streptococcus Anginosus In the intestine, a significantly higher risk of death and major cardiovascular events during the two -year follow -up period.
• An increased risk of death and poor results was not noted in stroke survivors with Anaerostipes Hadrus And Bacteroides Plebeius compared to witnesses.

“Our results offer new information on the link between bacteria bacteria and the risk of stroke, as well as potential stroke prevention strategies. Streptococcus mutans and Streptococcus Anginos are bacteria that contribute to dental caries by producing acids that decompose dental enamel.

“This highlights the importance of preventing dental caries, which can be carried out by reducing sugar intake and using toothpaste that targets these bacteria. It is essential to maintain good oral hygiene, ”said Tonomura.

Researchers hope to conduct similar studies in people who have not experienced stroke, but who have risk factors for stroke.

“The extent of the analysis to populations at risk of stroke is crucial to understanding wider implications and developing potential preventive strategies for people sensitive to stroke,” said Tonomura.

Since the study was conducted in a Japanese population with a relatively small sample size (189 patients with stroke and 55 non-time participants), the results may not be entirely generalizable to other populations or to more diverse groups.

“The oral and intestinal microbiome is strongly affected by the lifestyle. Other bacteria can be the main stakeholders in stroke in other countries, “said Tonomura.

“Poor oral health can lead to inflammation and can increase the risk of stroke. Increased levels of Streptococcus Anginosus Found in the intestine of patients with a recent stroke is intriguing, and the fact that the levels were linked to increased mortality two years after a stroke suggest that he could play a role in the risk of continuous stroke, ” said Louise D. McCullough, MD, PHD, FAHA, who is the distinguished president of Roy M. and Phyllis GOUGH HUFFINGTON of neurology at the McGovern Medical School; Head of neurology at the Memorial Hermann Hospital-Texas Medical Center and co-director of Uthealth Neurosciences, all in Houston, who was not involved in the study.

“Since this study was conducted after a stroke, examining a larger group of people who have not yet had a stroke but who have risk factors could improve our understanding of how these bacteria are linked to the risk of stroke.

“This knowledge could help improve prevention strategies.” McCullough also co-author the commentary and the microbiome published in the January 2024 issue of the American Heart Association Stroke newspaper.

Study details, background or design:

• The study included 250 people (average aged 70, 40% of women, all Japanese). Two hundred patients diagnosed (using brain imaging) with a stroke (bleeding or clot) in the last seven days have been compared to 50 people at the same age without a stroke of stroke who received a medical examination of routine. The control group can have other medical problems such as high blood pressure, diabetes or high cholesterol.
• Patients with stroke have been observed in the national cerebral and cardiovascular center in Osaka, the largest stroke center in Japan. The witnesses were participants in the SATA study based on the current population, which examines the cardiovascular risk factors in people of average age and the elderly.
• The researchers analyzed the oral and intestinal microbiomas using saliva samples and stools obtained from stroke patients and witnesses between July 2020 and July 2021. During a two -year follow -up period, they have Observed how many stroke patients have died or have had new cardiovascular events.

Co-authors, disclosure and sources of funding are listed in the manuscript.

About this news of research in neurology

Author: Karen Astle
Source: Aha
Contact: Karen Astle – Aha
Picture: The image is credited with Neuroscience News

Original search: The results will be presented at the International International Stroke 2025 ASA conference