Washington, July 9 (Inditop.com) Is the explosive growth of obesity worldwide being triggered by an infectious agent? Investigators are closing in on the role of oral bacteria as a potential direct contributor to obesity.

J.M. Goodson and colleagues, who carried out a recent study, measured salivary bacterial populations of overweight women.

Saliva was collected from 313 women with a body mass index (BMI, weight to height ratio) between 27 and 32 and bacterial populations were measured by DNA probe analysis. A BMI above 25 is a sign of being overweight.

Levels in this group were compared with data from a population of 232 healthy individuals from periodontal disease studies.

Analysis of saliva revealed that 98.4 percent of the obese women could be identified by the presence of a single bacterial species (Selenomonas noxia) at levels greater than 1.05 percent of the total salivary bacteria.

Analysis of these data suggests that the composition of salivary bacteria changes in overweight women.

It seems likely that these bacterial species could serve as biological indicators of a developing overweight condition.

Of even greater interest, and the subject of future research, is the possibility that oral bacteria may participate in the pathology that leads to obesity, said a International and American Associations for Dental Research release.

The study was published in the June issue of the Journal of Dental Research.