Study shows mouth bacteria could be used to identify ethnicity

October 23, 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 study participants in different concentrations according to their ethnicity. According to the scientists, the findings could help explain why some ethnic groups, and African-Americans in particular, are more susceptible to gum disease and provide further evidence of the necessity of personalized dental treatments. The study, titled “Deep Sequencing Identifies Ethnicity-Specific Bacterial Signatures in the Oral Microbiome,” was published online on Oct. 23 in the PLOS ONE journal.