New York, Oct 25(PTI): The bacteria in the human mouth is unique and can be as powerful as a fingerprint to identify a person, a new study led by an Indian-origin scientist has found.

Scientists have used oral bacteria - particularly those nestled under the gums - to identify a person's ethnicity.

Scientists identified a total of almost 400 different species of microbes in the mouths of 100 study participants belonging to four ethnic affiliations: non-Hispanic blacks, whites, Chinese and Latinos.

Only 2 per cent of bacterial species were present in all individuals - but in different concentrations according to ethnicity - and 8 per cent were detected in 90 per cent of the participants.

Researchers found that each ethnic group in the study was represented by a "signature" of shared microbial communities.

"This is the first time it has been shown that ethnicity is a huge component in determining what you carry in your mouth," said Purnima Kumar, associate professor of periodontology at The Ohio State University.

"No two people were exactly alike. That's truly a fingerprint," said Kumar, senior author of the study.

Kumar used a DNA deep sequencing methodology to obtain an unprecedented in-depth view of these microbial communities in
their natural setting.

When the scientists trained a machine to classify each assortment of microbes from under the gums according to ethnicity, a given bacterial community predicted an individual's ethnicity with 62 per cent accuracy.

he classifier identified African Americans according to their microbial signature correctly 100 per cent of the time.

he research also confirms that one type of dental treatment is not appropriate for all, and could contribute to a more personalised approach to care of the mouth.

"The most important point of this paper is discovering that ethnicity-specific oral microbial communities may predispose individuals to future disease," Kumar said.

hough it's too soon to change dental practice based on this work, she said the findings show that "there is huge potential to develop chair-side tools to determine a patient's susceptibility to disease."

Kumar and colleagues collected samples of bacteria from the saliva, tooth surfaces and under the gums of the study participants.