Newborn babies are born with a type of bacterium in their gut that could be used to develop new personalised infant therapeutic probiotics, finds a new study involving UCL researchers.
In the largest study of UK baby microbiomes to date, published in Nature Microbiology, researchers from UCL, the Wellcome Sanger Institute and the University of Birmingham, used whole genome sequencing to analyse stool samples from 1,288 healthy infants, all under one month old from the UK Baby Biome Study.
They found that all newborn babies fall into one of three microbiome profiles, each characterised by a different dominant pioneer bacterium.
The gut microbiome is a complex ecosystem of millions of microbes that are vital for human health and important in immune system development. It begins to form immediately at birth.
Two of these pioneer bacteria, Bifidobacterium longum subsp. longum (B. longum) and Bifidobacterium breve (B. breve), are considered beneficial as they promote the stable colonisation of other beneficial microbes.
B. breve was found to be genetically adapted to make full use of the nutrients in breast milk, suggesting that it is the most suited to thrive in a baby's microbiome.
And the team found that this bacterium can also block potential pathogens from colonising the babies' gut, highlighting its role as a possible natural probiotic.
However, the third bacterium (Enterococcus faecalis or E. faecalis) is considered risky, as it can lead to the colonisation of antibiotic-resistant bacteria. This can interfere with the development of the infant microbiome and increase the risk of pathogens colonising the gut.
The researchers hope that their findings could support the development of infant formulas and therapeutic probiotics containing the most effective natural strains for the baby's gut.
Co-author, Professor Nigel Field (UCL Institute for Global Health) said: "While our study has shortlisted three pioneer bacteria as important for babies' microbiome development, it remains to be determined if and how different pioneer bacteria affect health and diseases, both in childhood and later in life. The UK Baby Biome Study is actively following up participants to give clues about this, and now even bigger cohorts are needed to investigate the role of the infant microbiome on health."
In the future, it could be possible to predict how a baby's gut will develop by mapping their microbiome profile right after birth to assess which pioneer bacteria they have. If needed, a personalised probiotic could be provided to help promote healthy microbiome development and protect against potentially pathogenic infections.
Currently, most commercial infant probiotics contain a different bacterial strain (Bifidobacterium longum subsp. infantis or B. infantis), which is not commonly found in the early microbiomes of infants in industrialised societies like the UK and the US.
This suggests that B. breve could be a more effective natural probiotic.
Dr Yan Shao, first author from the Wellcome Sanger Institute, said: "If we think of a newborn baby's gut as an ecosystem that starts to establish right from birth, there was very little known about which and how microbes plant the very first seeds to establish themselves before the findings of the UK Baby Biome Study. By analysing the high-resolution genomic information from over 1,200 babies, we have identified three pioneer bacteria that drive the development of the gut microbiota, allowing us to group them into infant microbiome profiles. Being able to see the make-up of these ecosystems and how they differ is the first step in developing effective personalised interventions to help support a healthy microbiome."
Around 85 per cent of the babies studied were breastfed in the first few weeks of life. Researchers found that breastfeeding versus formula feeding did not seem to influence the type of pioneer bacteria in the baby's gut, however the use of antibiotics did. Researchers highlight that other factors such as maternal age and how many times someone has given birth may also play a role.
However, further research such as the Microbes, Milk, Mental Health and Me project is needed to understand the long-term impact of pioneer bacteria on health. This project, co-led by UCL is part of the Children Growing Up in Liverpool (C-GULL) study involving 10,000 mothers and infants.
This extensive research seeks to explore how factors such as the infant gut microbiome and early life feeding affect brain development, behaviour, emotions and mental health later in life.
Professor Louise Kenny, Lead Investigator of C-GULL from the University of Liverpool, said: "Decisions around mode of childbirth and breastfeeding are complex and personal, and it's important to note that there is no one size fits all approach when it comes to what the best options are for you and your baby. It is also important to note that we still have an incomplete understanding of how the role of mode of birth and different methods of infant feeding influence microbiome development and how this impacts later health. That's why this research is vital. We must continue to find new ways to ensure that all children are supported to have the best possible start in life."
