When babies are born, microbes from their mothers rapidly "colonize" their bodies.

The microbes slowly increase and mature as the youngsters grow up, allowing the formation of a unique set of gut microbiome.

The role of the gut microbiome extends beyond digesting food. Previous studies suggest that they may also play a role in a person's immune system.

What could possibly happen if the gut microbiome of babies is affected by outside species?

Antibiotic Treatment And C-Section

In recent years, many scientists have become concerned that modernization may upset the establishment of microbiome in babies.

For instance, going through C-section instead of normal delivery would mean that newborn babies could encounter microbes from hospital environments, rather than the typical species from the mother.

Another example is the possible effect of antibiotics to the gut microbiome. Designed to treat infectious diseases, the antibiotics might also assault the microbes that babies rely on.

Scientists believe the attack on gut microbiome could negatively affect the health of babies later in life as these sets of bugs have been found to influence obesity, allergies and asthma.

However, these scenarios contain flaws. In mice and humans, it is evident that antibiotics and C-section can affect the gut microbiome.

As The Atlantic wrote, there is a tendency to assume that the alterations are bad, that they last long and that they matter.

Determining The Truth

Two separate studies may offer further insight on the effects of antibiotic treatment to newborn babies.

The first research, which is published in the journal Science Translational Medicine, was led by Ramnik Xavier and Moran Yassour from Broad Institute.

The second report, also featured in the same journal, was conducted by Martin Blaser and Nicholas Bokulich from New York University.

Both teams collected stool samples from infants. The Broad Institute team collected 39 stool samples, while the NYU team gathered 43, over the first three years of the youngsters' lives.

The findings of both reports showed that a common group of bacteria known as Bacteroides is clearly rare from the microbiome of first-year infants who were born through C-section.

Does that mean there was a disruption? Is the lack of Bacteroides something bad inflicted by an unnatural birth?

Scientists say that it is not that simple. The Broad Institute team actually found that babies born of natural delivery had the same low-Bacteroides signature. They have yet to understand why.

Additionally, both reports found that the repeated use of antibiotics in children reduced the diversity of bacteria that are part of a healthy microbiome.

The NYU study discovered that antibiotic treatment "delayed" the maturation of children's microbiomes, while the other team found that antibiotics made babies' microbiome less stable.

The findings of both studies echo past research that highlighted how C-section and antibiotic treatments affect babies' gut microbiome.

What's Next?

In the meantime, NYU researchers are currently studying whether swabbing infants delivered by C-section with bacteria from the mother's birth canal could make their microbiome resemble those of babies born by natural delivery.

Both the Broad Institute and NYU teams will continue tracking the children involved in the studies to determine if early differences in gut microbiome actually matter later in life.

For now, researchers said they have provided a reason why prescribing antibiotics for toddlers and infants under three years of age may not be a "good thing."

Photo: Donnie Ray Jones | Flickr