London, Aug 11 (IANS) A new species of bacteria discovered in the mouth can help scientists understand tooth decay and gum disease and enable them devise better treatment, according to a report. “The healthy human mouth is home to a tremendous variety of microbes including viruses, fungi, protozoa and bacteria,” said William Wade from King’s College London Dental Institute.

“The bacteria are the most numerous: there are 100 million in every mm of saliva and more than 600 different species in the mouth. Around half of these have yet to be named and we are trying to describe and name the new species,” he added.

Scientists studied healthy tissue as well as tumours in the mouth found three strains of bacteria called Prevotella that could not be identified. Prevotella species are part of the normal microbial flora in humans and are also associated with various oral diseases and infections in other parts of the body. The researchers named the new species Prevotella histicola; histicola means ‘inhabitant of tissue’.

“Interestingly, this species was isolated from within the oral tissues, both in oral cancers and normal, healthy tissue,” said Wade. “This confirms other work showing that oral bacteria can invade both tissues and individual cells.”

Tooth decay and gum disease are the most common bacterial diseases and are caused by changes in mouth microbes. To understand them better, scientists first need to know which bacteria are present in human mouths.

Understanding the composition of the oral microbiota will also help scientists devise new prevention measures and treatments for oral diseases.

“A detailed description and name for each species of bacteria are needed so that different laboratories can recognise all of the bacterial species present in the mouth,” said Wade.

The research has been published in the August issue of the International Journal of Systematic and Evolutionary Microbiology.