US Pharm. 2023;48(2):4.

Bacteria known to cause oral infections may also be a contributory factor in patients developing potentially life-threatening abscesses on the brain, new research has shown. The study led by the University of Plymouth, England, and published in the Journal of Dentistry investigated brain abscesses and their association with bacteria that occur in the oral cavity. While this type of abscess is relatively uncommon, it can nonetheless result in significant mortality and morbidity.

Researchers examined the records of 87 patients admitted to hospitals with brain abscesses and used microbiological data obtained from abscess sampling and peripheral cultures. This enabled the scientists to investigate the presence of oral bacteria in patients’ brain abscesses where a cause of the abscess had either been found, as was the case in just 35 of the patients, or not found.

Their results showed that the 52 patients in whom no cause had been found were about three times as likely to have oral bacteria present in their samples. Those patients also carried significantly higher counts of Streptococcus anginosus, a bacterium that can lead to pharyngitis, bacteremia, and infections in internal organs, such as the brain, lung, and liver. This bacterium is often found in dental abscesses, and the researchers said the findings suggest that the oral cavity could be considered a source of infection in cases of brain abscess where no clear cause has been identified.

Holly Roy, a National Institute for Health and Care Research clinical lecturer in neurosurgery based at the University of Plymouth and University Hospitals Plymouth NHS (National Health Service) Trust, is the study’s lead author. She said, “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. It highlights the importance of using more sensitive techniques to assess the oral cavity as a potential bacterial source in brain abscess patients. It also highlights the importance of improving dental care and oral hygiene more generally.”

The study is part of ongoing research within the University’s Oral Microbiome Research Group, led by Raul Bescos Garcia and Zoe Brookes, to explore the links between the oral microbiome and a range of cardiovascular and neurologic conditions.

Other clinical trials are underway investigating the links between gum health and Alzheimer’s disease and identifying patients with high cardiovascular risk in primary care dental clinics. This is because an altered balance of oral bacteria (microbiome) that arises during gum disease, scientists have found, can lead to high blood pressure and strokes.