Study shows mouth bacteria could be used to identify ethnicity

0 23 October 2014

COLUMBUS, Ohio, USA: Microbiologists have suggested that bacteria present in the oral cavity are a reliable indicator of a person’s ethnicity. In a study of participants from four different ethnic groups, they found that each group had an individual set of oral microbes. They believe that these microbes might also predispose individuals to certain oral diseases. The study included 192 healthy individuals aged 18 and over who consisted of non-Hispanic blacks, non-Hispanic whites, Chinese people and Latinos. Researchers at the Ohio State University compared the oral microbial communities they obtained from bacterial samples from the participants’ saliva, tooth surfaces and gums after sequencing their DNA. Using a special machine, they were able to predict an individual’s ethnicity with 62 percent accuracy based on a given bacterial community. African-Americans were correctly identified according to their microbial signature 100 percent of the time. Latinos were identified with 67 percent accuracy and Caucasians with 50 percent. The classifying machine performed best when subgingival microbes were used. This was attributed to the fact that these bacteria are the least likely to be disrupted by environmental changes in the mouth, such as food, toothpaste and tobacco. Overall, they found 398 species, with an average of about 150 species per person. Only 2 percent were present in all

0 23 October 2014

AUSTIN, Texas, USA: Studies on the human microbiome have shown that shifts in oral microbiota are associated with a number of diseases, including obesity, Crohn’s disease, diabetes and periodontitis. Now, U.S. scientists have found that oral bacteria act differently in diseased patients compared with healthy individuals. They believe that the findings could be used to develop methods to prevent or even reverse diseases such as periodontal disease. Although it is known that the composition of the microbiome changes during the transition from health to disease, it is still unclear how specific activities of different members of the microbial community affect diseases. In order to understand how different bacteria act in healthy and diseased individuals, researchers at the University of Texas at Austin examined periodontal plaque samples from ten patients from Izmir in Turkey with aggressive periodontitis. Using supercomputers, the researchers compared the expression of 160,000 genes in healthy and diseased periodontal communities and found that these communities show defined differences in metabolism. “In other words, a species of bacteria that ate one thing, such as fructose, can switch to a different kind of sugar to feed on if diseased,” explained Dr. Marvin Whiteley, professor of molecular biosciences at the university. A major question concerning the mechanism underlying the

0 23 October 2014

TOKYO, Japan: The results of a recently published study have shown that ozone nano-bubble water (NBW3) is very effective against two bacteria that cause periodontitis. The researchers believe that this new antimicrobial agent could be used in the development of new therapies for the inflammatory disease, which affects 15 to 20 per cent of middle-aged adults in its severest form worldwide. In in vitro experiments, researchers at Tokyo Medical and Dental University and the National Institute of Advanced Industrial Science and Technology in Japan tested the effectiveness of NBW3 against Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. They found that the levels of both bacteria dropped to below the lower limit of detection after only 30 seconds of exposure. In addition, they observed that NBW3 had no significant impact on human oral tissue. Using an in vitro human oral tissue model, composed of human-derived epithelial cells, they found only minor decreases in the viability of cells after 24 hours of exposure. Such models are used to test the toxicity and irritation potential of new dental materials and oral care products. According to the researchers, they are more predictive of human responses and more clinically relevant than are animal and monolayer cell culture test systems. Conventional antibiotic therapies for treating periodontitis hold the risk of sever