Bacteria From Mouth Can Lead to Heart Inflammation

A type of bacteria from the mouth can cause blood clots and lead to serious heart problems if it enters the bloodstream, a new study indicates.

The bacteria, called Streptococcus gordonii, contributes to plaque that forms on the surface of teeth. If the bacteria enters the bloodstream through bleeding gums, it can cause problems by masquerading as human proteins, the researchers found.

The study authors, from the Royal College of Surgeons in Ireland and the University of Bristol in the United Kingdom, discovered that S. gordonii can produce a molecule on its surface that enables it to mimic the human protein fibrinogen, which is a blood-clotting factor.

This activates platelets (cells that are found in blood and involved in clotting) and causes them to clump inside blood vessels. The resulting blood clots encase the bacteria, protecting the invader from the immune system and from antibiotics used to treat infection.

Platelet clumping can result in growths on the heart valves (endocarditis) or blood vessel inflammation that can block blood supply to the heart or brain.

The findings, to be presented at a Society for General Microbiology meeting in Dublin this week, could help lead to new treatments for infective endocarditis, said study author Dr. Helen Petersen.

"In the development of infective endocarditis, a crucial step is the bacteria sticking to the heart valve and then activating platelets to form a clot," Petersen said in a society news release. "We are now looking at the mechanism behind this sequence of events in the hope that we can develop new drugs which are needed to prevent blood clots and also infective endocarditis."

The researchers stressed that it's important to keep the gums healthy and get regular dental care.

"We are also trying to determine how widespread this phenomenon is by studying other bacteria related to S. gordonii," Petersen said. "What our work clearly shows is how important it is to keep your mouth healthy through regular brushing and flossing, to keep these bacteria in check."

Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.

More information

The U.S. National Heart, Lung, and Blood Institute has more about endocarditis.