• Sharing microbes
• Predicting social ties
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What is already known on this topic
The microbes that inhabit the human body, which are collectively known as the human microbiota, play a key role in health and disease. But how social contacts shape the human microbiota composition is poorly understood. -
What this research adds
By analyzing the microbiota of nearly 300 people from the Fiji Islands, researchers found that mouth and gut microbes are commonly transmitted between spouses. Compared to men, women harbor bacteria that are more closely related to those harbored by their close family and friends. -
Conclusions
Although the study didn’t determine the directionality of transmission nor whether it was direct, the findings open the door to understanding how the microbiota is shared between individuals.
Interests are not the only thing that friends have in common. Mouth and gut microbes, too, appear to be shared in close social networks. That’s according to a study by Ilana Brito of Cornell University in Ithaca, New York, and her colleagues.
The results, published in Nature Microbiology, reveal how routine social contacts shape the composition of the human microbiota.
Sharing microbes
The researchers analyzed the microbiota of 287 people living in five villages in the Fiji Islands. Because the villages are in remote locations and rely on local food and water, the team hypothesized that they could track bacterial strains within the communities.
Indeed, people who lived in the same house, and spouses in particular, had very similar strains in their gut microbiota.
Individuals who shared many gut microbes were not the same as those who shared mouth bacteria, and sharing of both gut and mouth microbiota was more associated with women in the network.
Although each pair of connected individuals had a unique signature of shared microbes, the researchers didn’t find bacteria that were consistently transmitted between people. They also didn’t observe any clear pattern of transmission.
The absence of a defined transmission pattern might be due to the fact that the communities analyzed could be prone to sharing bacteria between a wide range of people, for example during gatherings to drink kava, in which everyone shares a vessel and a cup.
Predicting social ties
Next, the researchers sought to predict specific social ties by just looking at shared bacteria. The team could accurately predict family ties, and spousal relationships in particular: nearly 25% of spouses could be easily predicted with high confidence.
Although the study didn’t determine the directionality of transmission nor whether it was direct, the findings open the door to understanding how the microbiota is shared between individuals.
Long-term intimate interactions such as marriage or cohabitation, which occur in adulthood, could influence the composition of the human microbiota, with possible implications on the overall health status of individuals, the scientists say.
