Microbiota - gestational age

A pre-term delivered infant is at greater risk for health complications. The microbiota of a pre-term baby is less stable than that of a baby born at the right term. The health risks that pre-term delivered babies face are related to the differences in the gut microbiota.

When a baby is born earlier than week 37, we talk about premature birth. A pre-term delivered baby is prone to health complications, more susceptible to infections (which are more dangerous as their immune system is not ready to face them yet). We know that the microbiota can play a role in the defense against pathogens. The microbiota development is affected by the birth mode, nutrition, environment and medication. All of these factors are not only associated with the microbiota, but also with the newborn physiology, growth and development. Some infants are at higher risks of different microbiota development because of the c-section delivery, antibiotic use and formula feeding (and/or sometimes enteral feeding also). All of these are common traits for pre-term delivered babies. Every one of these factors can lead to sub-optimal conditions for the microbes living in the intestines, so the microbiota of a pre-term born baby is less stable that that of a baby delivered in term. The immediate risks of a premature baby microbiota composition are the increased risk of sepsis and of necrotizing enterocolitis (NEC). All of these infections are life threatening for the baby. There is a direct correlation between the microbiota colonizing rate and the gestational age (meaning that the infants born at younger gestational age got less colonizing microbes).

Another major issue is related to the colonization with Bifidobacteria, which is delayed in pre-term born infants. The duration of the antibiotic treatment is associated with the delayed colonization too, as treating the premature baby with antibiotic form one to seven days will directly affect the colonization rate of Bifidobacteria. The longer the treatment, the longer it takes for Bifidobacteria to start colonize the intestine. To add to this problem, the respiratory support seems to prevent strictly anaerobes such as Bifidobacteria to colonize the intestinal tract. Instead, facultative anaerobes and aerobic bacteria could be present, many of them being opportunistic pathogens. This can contribute to higher risks of infection. The delay in the colonization with Bifidobacteria can be linked to nutritional status, as the lack of it can reduce the nutritional value because of the lesser degradation of the food. We all know that efficient energy uptake from food will improve the growth and development of the infant. All of these pre-term babies have increased colonization by potential pathogens and a delay/decrease colonization of Bifidobacteria.

Awareness of the possible benefits of the microbiota composition for pre-term born infants will help to develop strategies to improve health status of this vulnerable group of children.

Next post will be about the antibiotics effects on the microbiota.