American Chemical Society( August 9, 2023)
Breastfeeding has long been used as a method to help keep newborns healthy and protected
against a variety of diseases. But certain sugars naturally found in breastmilk could also help
prevent infections before a baby arrives. Researchers reporting in ACS Central Science have
found that these sugars can stop a common prenatal infection in human tissues and pregnant
mice. This could someday help avoid preterm births or complications without the need for
additional antibiotics.
One of the most common bacteria that can affect pregnancies is Group B streptococcus (GBS).
If left untreated, GBS infections can potentially lead to adverse effects, including neonatal
pneumonia or preterm birth. Though treatments are available, they primarily rely on antibiotics,
which can give rise to resistant strains. However, many of the compounds already present in
human breast milk, such as human milk oligosaccharides (HMOs), naturally have antibacterial
effects.
Previously, Steven Townsend, Jennifer Gaddy and colleagues explored the antimicrobial
effects of HMOs, finding that they could inhibit growth of GBS in vitro and in certain
reproductive cells. But before the compounds could be used to boost existing antibiotics or
become a new therapeutic option entirely, researchers need to show how the sugars work in
many tissues and in vivo. So now, the team wanted to investigate HMO activity in GBS
infections in pregnant mice and human tissues.
The team first analysed the protective effects of HMOs on human tissue infected with GBS,
using both ex vivo foetal tissues and an organoid model of the vagina. When they added a
mixture of HMOs designed to mimic the sugar composition in breast milk, the bacteria could
not adhere and form colonies. The HMO mixture was then tested in pregnant mice infected
with GBS.
The treated mice had a relatively typical level of inflammation, reduced numbers of bacteria in
several reproductive tissues, and experienced no instances of preterm births, ruptured
membranes or maternal deaths. Taken together, these results demonstrate that HMOs can have
antimicrobial effects without additional antibiotics. The researchers say that this work could
allow for these sugars to be used as a viable therapeutic option to treat GBS infection and
prevent adverse pregnancy outcomes