Transmission of Human-Associated Microbiota Along Family and Social Networks

By Dr. Katie E.Golden

CMIT researchers study village populations in Fiji to try and understand how social networks influence the development of the human microbiome.

The microbiome is an integral part of the human gastrointestinal system that contributes to our daily metabolism and immune function. It develops and changes throughout our lifespan, and scientists are currently working to understand the factors that influence its variation and dynamic nature. We still know very little about the genetic, physiologic, and environmental forces that ultimately determine the colonization of specific microbial populations in our intestine.

There has been a body of research that shows the role of mother-to-child transmission in the early establishment of an individual’s microbiome. A group of dedicated researchers recently took this one step further, and investigated how interpersonal relations contribute to the continued evolution and maintenance of our microbiota later in life. In a manuscript recently published in Nature Microbiology, Brito et.al. (along with colleagues from CMIT)¹ ask the important question: is there commensal transmission between friends and family?

They carried out their research in Fijian villages, with tight social networks that are relatively isolated from other populations, and performed metagenomic sequencing of bacterial species from paired oral and fecal samples. While they did observe high rates of transmission within the populations, specifically among households and spouses, they did not identify any clear direction or patterns of bacterial transmission. Interestingly, they found that women’s microbial profiles have more commonality with their surrounding contacts than men. They also studied whether they could predict intimate relationships based on bacterial DNA profiles, and found that spousal relationships were much easier to predict than household members.

Given the critical role of the intestinal microbiota in various diseases, understanding transmission patterns of both commensal and infective strains is a fundamental step in understanding microbiome-associated pathophysiology. Brito and her team’s work has opened an important door for future research to characterize the factors contributing to microbiome transmission and colonization.

1. Brito IL, Gurry T, Zhao S, Huang K, Young SK, Shea TP, Naisilisili W, Jenkins AP, Jupiter SD, Gevers D, Alm EJ. Transmission of human-associated microbiota along family and social networks. Nat Microbiol. 2019 Mar 25.