A study has shed new light on the movement of bacteria during pregnancy.
Pregnant women given nose drops containing harmless bacteria did not pass it on to their babies. This suggests the bacteria babies receive are selectively filtered.
The findings suggest infants are not passive recipients of their mothers’ bacteria, and will prompt new research into how babies can be protected from infections.
The research was jointly led by Professor Robert Read and Dr Chrissie Jones at the NIHR Southampton Biomedical Research Centre.
Dr Anastasia Theodosiou was the lead investigator and author on the paper, published in the Lancet Microbe.
Bacterial starter set
The complete set of bacteria that a baby naturally has living in their nose, throat and airways is known as their ‘respiratory microbiome’.
The microbiome helps train the baby’s immune system, and microbiome disruption may be linked to later health problems, like infections and allergies.
While the microbiome mainly comes from the baby’s mother, it is unclear exactly how this happens.
This study investigated whether babies whose mothers were given the harmless bacteria Neisseria lactamica during pregnancy acquired it from their mothers after birth.
Neisseria lactamica is naturally found in young children’s throats, but it is rarely found in babies. People carrying Neisseria lactamica are less likely to carry or get ill from Neisseria meningitidis, the bacteria that causes meningitis.
The researchers wanted to know if giving pregnant women Neisseria lactamica could help babies acquire this protective bacteria from birth.
Unexpected results
A total of 21 pregnant women were infected with the Neisseria lactamica under controlled conditions at the NIHR Southampton Clinical Research Facility. This had previously been shown to be safe in research with non-pregnant adults.
Of these 21 women, 15 were subsequently found to have the bacteria living in their throats. However, none of their babies acquired Neisseria lactamica by four months after birth. This suggests it wasn’t passed on.
Another type of bacteria called Moraxella catarrhalis, which is commonly found in babies and adults, was transferred to six of the babies from their mothers.
This suggests there may be a selective process that shapes newborn babies’ respiratory microbiome.
Dr Theodosiou, now a Clinical Lecturer at the University of Glasgow, said: “We often think of a baby as being a passive recipient of its mother’s microbiome. This result is so exciting, as it suggests the baby may play a more active role. Our findings will help us design trials to encourage protective bacteria in babies.”
The research was funded by the Medical Research Council and the National Institute for Health and Care Research (NIHR).
Pregnant women in research
For many years, pregnant women have been excluded from research trials due to safety concerns.
However, this has been changing in recent years, to make research more inclusive and to improve healthcare for pregnant women and their babies.
The researchers also did a questionnaire-based study, exploring the perspectives of participants in the trial. This has been published in The Pediatric Infectious Disease Journal.
As the first ever controlled infection study in pregnant women, this trial is important, as it shows that this type of research can be both safe and acceptable.
These findings pave the way for future studies that could help protect infants from infections.
Comments