Summary Oral microbiome dysbiosis has been associated with various local and systemic human diseases, such as dental caries, periodontal disease, obesity, and cardiovascular diseases. Bacterial composition can be affected by age, oral health, diet and geography, although information is still lacking on the natural variation found in the general public. In this study, citizen scientists used a crowdsourcing model to obtain oral bacterial composition data from visitors to the Denver Museum of Nature and Science to determine whether previously suspected oral microbiome associations with demographics, lifestyle, and / or the genetics of an individual are robust and generalizable enough to be detected within a general population. Consistent with previous research, we found that bacterial composition is more diverse in juvenile microbiomes compared to adults. Adult oral microbiomes were primarily affected by oral health habits, while youth microbiomes were affected by biological sex and weight status. The oral pathogen Treponema was detected more frequently in adults without recent visits to the dentist and in obese young people. Additionally, the oral microbiomes of participants from the same family were more similar to each other than the oral microbiomes of unrelated individuals. These results suggest that previously reported oral microbiome associations are observable in a human population that contains natural variation commonly found in the general public. Furthermore, these results support the use of crowdsourcing data as a valid methodology for obtaining community-based microbiome data. |
Context and results
Most people know that good oral hygiene (brushing, flossing, and regular visits to the dentist) is related to good health. Microbiome researchers at Colorado State University offer new evidence to support that conventional wisdom, taking a closer look at the invisible communities of microbes that live in every mouth.
The oral microbiome , the sum total of microorganisms, including bacteria and fungi, that occupy the human mouth, was the subject of a crowdsourced citizen science-led study by Jessica Metcalf’s research lab at CSU and the team at research by Nicole Garneau at Denver Museum of Nature and Science. Published in Scientific Reports , the study found, among other things, a correlation between people who did not visit the dentist regularly and a greater presence of a pathogen that causes periodontal disease.
For the experiments, conducted by Garneau’s community science team in the Taste Genetics Laboratory at the museum, a large cross-section of museum visitors underwent a cheek swab and answered simple questions about their demographics. , lifestyles and health habits.
Microbial DNA sequencing data analyzed by Metcalf’s group broadly revealed that oral health habits affect bacterial communities in the mouth. The study underscored the need to think of oral health as strongly linked to whole-body health.
"Our study also showed that crowdsourcing and using community scientists can be a very good way to get this type of data, without having to use large, case-controlled studies," said Zach Burcham, postdoctoral researcher and lead author. from the article. Senior author Metcalf is an associate professor in the Department of Animal Sciences and a member of the CSU Microbiome Network.
Cheek swabs
In 2015, paper co-author Garneau and her team trained volunteer citizen scientists to use large swabs to collect cells from the cheeks of museum visitors, a naturally diverse population, who consented to the study. These trained citizen scientists helped collect swabs from 366 individuals: 181 adults and 185 youth ages 8 to 17.
The original impetus for the study was to determine if and to what extent the oral microbiome contributes to how people taste sweets . By collecting this data, which was also reported in the paper, the researchers saw more significant data points about oral health habits.
To help translate the data, Garneau turned to Metcalf’s team of experts at CSU. Burcham and microbiome scientists used sophisticated sequencing and analysis tools to determine which microbes were present in which mouths. The sequencing data was done in collaboration with scientists in Rob Knight’s group at the University of California, San Diego. A nutrition team from Michigan State University also brought expertise in the importance of infant and maternal relationships to the data analysis.
"Together, we had a dream team to use community science to answer complicated questions about human health and nutrition, using next-generation microbial sequencing and analysis," Garneau said.
Flossing and Regular Dental Care
The study grouped together people who flossed or didn’t floss (almost everyone said they brushed, so that wasn’t a useful data point). Participants who flossed were found to have lower microbial diversity in their mouths than those who did not floss. This is likely due to the physical removal of bacteria that could be causing inflammation or disease.
Adults who had been to the dentist in the past three months had lower overall microbial diversity in their mouths than those who had not gone in 12 months or more, and they had less of the periodontal disease-causing oral pathogen, Treponema . This, again, was probably due to dental cleaning that removed the rarer bacterial taxa in the mouth. Young people tended to have had a dental visit more recently than adults.
Youth microbiomes differed between men and women, and by weight. Children considered obese based on their body mass indexes had distinct microbiomes compared to non-obese children. Obese children also tend to have higher levels of Treponema, the same pathogen found in adults who had not been to the dentist in more than a year. In other words, the researchers saw a possible link between childhood obesity and periodontal disease. "This was very interesting to me, that we were able to detect this data in such a general population, with such a variable group of people," Burcham said.
Other data discovered: The microbiomes of the youngest participants, mostly in the 8- to 9-year-old range, had more diversity than those of adults.
However, adult microbiomes vary more from person to person. Researchers think this is because adults’ environments and diets are broader than children’s.
They also saw that people living in the same household shared similar oral microbiomes .
"When you look at families that live together, you find that they share more of those rare taxa, the bacteria that aren’t found as often at the highest abundances," Burcham explained. It was a data point that underscored the relevance of the built environment in relation to the microbial communities in our bodies.
Working on the study of the mouth was fascinating, although outside Burcham’s normal scope; Typically, he focuses on studying the microbial ecology of decomposition.
"I think our lives are essentially driven by our microbiomes and affected by our microbiomes, it’s interesting, no matter what system we’re looking at," Burcham said.
