gut microbiome. Courtesy of Getty Images Bank
A study has found that the microbiome, a community of microorganisms living in the human body, is spread through close contact with people. This means that the microbiome, other than what was acquired from the mother at birth, is acquired through social interactions.
A research team led by Nicola Segata, a professor at the Department of Computational Biology at the University of Trento, Italy, published the results of the study in the international journal Nature on the 18th (local time).
Microbiome, which refers to microorganisms living in our body and their genetic information, regulates immune function, facilitates digestion, and produces various metabolites. Through previous studies, it is known that the microbiome is related to obesity, diabetes, atopy, cancer, autoimmune diseases, depression, cranial nerve diseases, allergic diseases, and infectious diseases. However, it is not known in detail how bacteria and other microorganisms that make up the microbiome are formed and spread in the body.
The research team analyzed more than 9,000 stool and saliva samples from 20 countries to examine how the bacteria spread between generations and between people in close contact, such as family members, friends and partners. Intergenerational transmission means vertical movement, and transmission between people in close contact means horizontal movement.
As a result of the study, the first transmission of the microbiome occurred at birth. There was a 50% chance that the microbiome of the mother and the newborn baby were the same. The microbiome obtained from the mother and breast milk, including the placenta and vagina, has been shown to be very long-lasting.
The microbiome, which was not discovered in childhood but was discovered after becoming an adult, has been confirmed to be acquired through social interactions such as family, friends, and partners. In the case of people living in the same apartment or meeting and interacting constantly, it was confirmed that the number of bacteria exchanged was proportional to the amount of time shared.
It was also confirmed that the oral microbiome has a higher rate of horizontal transmission than the gut microbiome. During the same cohabiting period, the sharing rate of oral microbiome strains was 32%, whereas the sharing rate of intestinal microbiome strains was 12%.
When comparing cohabiting and noncohabiting relationships, the share of oral strains in cohabitation was 10 times higher than in noncohabitation. In other words, living together had a greater impact on the formation of the oral microbiome than age or genetics. Also, bacteria that survive outside the body better are transmitted far more frequently than other bacteria.
Professor Nicola Segata said, “This study is the largest and most diverse large-scale cohort study to date on the spread of the microbiome, in which 20 countries and 18 institutions participated in the study.” “Diseases such as cardiovascular disease, diabetes, and cancer are contagious However, because it is partly related to the altered composition of the microbiome, future therapies that act on microbiome propagation will need to be explored to reduce disease risk.”