A new study is identifying a link between bacteria that cause oral infections and abscesses in the brain. Abscesses are groups of pus that can accumulate in the brain when there’s an infection. Though these abscesses are “relatively uncommon,” they can be deadly.

For the study, researchers looked at 87 brain abscess patients who were being treated in the hospital and took culture samples of the microbial content of the abscesses. They could see whether oral bacteria were also present and if they could determine what caused the abscess or not.

Of the 87 patients, 35 had a known cause. However, 52 of them did not – it was three times more likely for those 52 patients to have oral bacteria in their samples. These same patients also had more Streptococcus anginosus, which is also found in oral abscesses and can cause infections in internal organs.

Lead author of the study, Dr. Holly Roy says, “While many potential causes of brain abscesses are recognized, the origin of infection often remains clinically unidentified. However, it was still surprising to frequently find orally occurring bacteria in brain abscesses of unexplained origin.”

Researchers say this is an obvious area to investigate when no other cause of brain abscesses have been found.

This study highlights the importance of good oral hygiene, as previous studies have connected oral health with heart health, digestive health, and immunity.