In the study, the scientists observed that people with Alzheimer's Disease presented higher rates of toxic enzymes produced by P. gingivalis called gingipains.
The findings are published in the latest edition of the journal Science Advances.
The BDA claims this study highlights the fact that oral health can't remain an "optional extra" in the health service. Some had HIV-related dementia that resolved after they got antiviral drugs.
When the team examined the brains and cerebrospinal fluid of Alzheimer's patients, they found DNA from the bacterium.
Tau is normally found in the brain - even in healthy people - but under certain conditions it can clump together into tangles that injure nearby tissue and presage cognitive decline.
Interestingly, the brains of 50 control bodies, who were elderly but did not suffer from Alzheimer's, contained low levels of gingipains. That early appearance is important, Lynch says, because "you would expect it to be there before the onset" of symptoms. P. gingivalis causes periodontitis, an infection that destroys the gums and can lead to tooth loss.
Researchers sampled brain and spinal cord fluid from eight people after a normal night of sleep and again after a night when they were kept awake for the entire night. A compound called COR388, which was formulated by the start-up, reduced bacterial load of an established Pg brain infection, blocked the production of amyloid-beta, reduced neuroinflammation, and protected the neurons in the hippocampus. Her team previously found that P. gingivalis actively invades the brains of mice with gum infections.
"That is why we have created highly potent, brain penetrant, anti-gingipain small molecules to target P. gingivalis and gingipians in the brain", he said.
'But the evidence of causation hasn't been convincing. "These are unusual ideas, but they seem to be getting some traction".
AD results from both genetic and environmental risk factors, such as ageing, which combine to result in epigenetic changes, leading to gene expression changes, but little is known about how that occurs.
One drug, given to mice in food, effectively treated P. gingivalis brain infections and prevented the loss of memory neurons. However, the second theory is the most concerning one. But he's skeptical that the bacteria or its toxin directly cause Alzheimer's.
As the number of Latinos in the United States grows, it will be vital that physicians and dementia clinicians use protocols that allow them to best assess the Latino demographic, the study said.
Howard Fillit, a neuroscientist and chief science officer at the nonprofit Alzheimer's Drug Discovery Foundation in New York City, is more impressed.
"The idea that bacteria and viruses may play a part in brain disease like Alzheimer's is not necessarily new", Rebecca Edelmayer, Ph.D., director of scientific engagement for the Alzheimer's Association, told CBS News. They found 96 percent of 53 patients with the condition had RgpB, or a form of the gingipains enzyme known as arginine-gingipain.