The communities of bacteria (our microbiome) and viruses (our virome) living in our gut play a crucial role in various aspects of our health, including our immune system, digestion, and metabolism. These microbial communities are influenced by various factors, including diet, lifestyle, medication, and human genetics.
In Garmaeva and Sinha’s new study, the authors tracked the mother and infant gut microbiome and virome during pregnancy and across the first year of the baby’s life. They were looking for factors that define early microbial colonization of the gut and whether babies receive their gut viruses from their mothers.
For this study, the researchers processed hundreds of stool samples collected throughout pregnancy up to one year post-birth from 30 mother-infant pairs (including two sets of twins) who are part of the Lifelines NEXT birth cohort. The researchers thoroughly analyzed the microbiome and virome in these samples to find potential clues to the origin of the gut microbes in the infant gut.
In addition to the stool samples, the study examined questionnaires filled out by Lifelines NEXT mothers during and after their pregnancy. As these questionnaires asked about factors such as infant feeding practices, mode of delivery, and place of delivery, the researchers could explore how these factors impact the early gut microbiome and virome.
Previous research has mostly focused on the vaginal microbiome as a source of the early microbes in infants. The new study reveals that some of the bacteria and viruses found in babies' intestines originate from their mother's gut. Interestingly, the researchers also found that, while the mother’s gut microbiome changes during early pregnancy, it then remains stable from the second trimester up until three months after delivery. Similarly, the maternal virome also remains stable during the late pregnancy and early post-delivery period.
This is one of the first studies in the world to describe the gut virome composition in early life, and one of the first to demonstrate that infants obtain some of their viruses directly from their mother’s gut. Understanding how a mother's gut flora can influence that of their baby is important for understanding the origin of the gut microbiome and its relation to health. As both lifestyle and medication can affect the mother's microbiome, these changes may in turn be transmitted to the baby.
Garmaeva and Sinha, together with a large team from the Groningen Microbiome Hub and under the supervision of Prof. Alexandra Zhernakova, have also initiated further research into the environmental factors that can impact a baby's early life virome and microbiome. The current study is just the beginning of a larger set of analyses. Utilizing the data from the 1,450 mother-infant pairs from Lifelines NEXT, the researchers will now follow-up their findings on a much larger scale and focus on the links between early microbes and health outcomes, with the first results expected later this year.
Link to publication: Transmission and dynamics of mother-infant gut viruses during pregnancy and early life | Nature Communications
