In what could lead to better ways to prevent or even reverse the gum disease periodontitis and diabetes, researchers have found that bacteria inside your mouth drastically change how they act when you are sick.

"The main thing that they change when they go from health to disease is that they change their metabolism," said Marvin Whiteley, a professor at University of Texas, Austin.

In other words, a species of bacteria that ate fructose for example can switch to a different kind of sugar to feed on if one is ill.

Bacteria share nutrients and one species will even feed on another as they constantly interact.

"The thing that we found in this paper," said Whiteley, "is that this sharing, and how they interact with each other changes quite drastically in disease than it does in health".

For the study, the researchers used supercomputers at the Texas Advanced Computing Center (TACC).

The researchers chose 60 different species of bacteria to represent the total community. More than 160,000 genes were analysed, yielding 28 to 85 million reads of RNA snippets, including about 17 million mRNA reads for each sample.

"RNA, for those who know about computers, is kind of like the RAM (random access memory), the working memory of the cell," study co-author Keith Turner, a postdoctoral researcher in Whiteley's lab, explained.

The RNA sample acts like a memory image or 'core dump' to reveal the processes of the as-yet unknown bacterium it came from.

The study appeared in the journal mBio.