Bacterial meningitis is a severe condition that is linked to high mortality. Unfortunately, newborns are much more susceptible to bacterial meningitis. In fact, this infection occurs more than 30 times more frequently in newborns.

The most common strain of this infection to impact newborns is Group B streptococcus (GBS). This exact strain rarely causes issues in the adult population.

Typically, GBS infection occurs after bacterial colonization within the gut. The gut microbiota is incredibly important as it typically prevents gut pathogens from influencing the body, aids in digestion, and helps the immune system develop. However, newborns do not have any gut microbiota. This is something that develops after birth, therefore making newborns incredibly susceptible to GBS.

A new study has demonstrated the importance of the gut microbiome and epithelial barriers in newborn GBS.

The Study

This study was completed by researchers from the Institut Pasteur, Necker-Enfants Maldades Hospital, and Inserm, Université de Paris. It was recently published in Cell Reports.  Its primary aim was to understand why there is such susceptibility to GBS meningitis in newborns.

They utilized a mouse model to show that it is the immaturity of the epithelial barriers (like gut plexus and choroid plexus), and the immaturity of the gut microbiota, which make newborns more susceptible. The choroid plexus is the interface in-between the cerebrospinal fluid and the blood which moves into the brain. This immaturity then influences all stages of the infection, ranging from gut colonization to dissemination within the brain.

The immaturity of the epithelial barriers was fully unexpected in this study. The researchers explain that the Wnt signaling pathway is more active for newborns. This leads to the barrier function of the gut and the choroid plexus to be less effective.

Together these immaturities can lead to-

• Bacteria more easily being able to colonize in the gut
• The barrier stopping bacteria from entering the brain being less effective
• The immune system struggling to control infections

More largely, this study shows how important the gut microbiota is for protecting the body against infections, particularly in newborns.

You can read more about this study and GBS here.