Caesarean section recipients are usually given prophylactic antibiotics just before the procedure to prevent subsequent surgical site infections. But there are concerns about whether these antibiotics could have a negative effect on newborns and their microbiome if the drugs travel through the umbilical cord and reach the baby before the umbilical cord is cut. Now a study from the Netherlands has confirmed that while these antibiotics can cause subtle changes in babies’ microbiomes, these are far less significant than the impact of the way the babies are fed. The findings were reported in the journal on August 14 Cell host and microbe.
“We decided to conduct this study because it answers an important clinical question with potentially profound implications for infant health,” said first and corresponding author Trishla Sinha of the University Medical Center Groningen. “It is critical to balance high-quality evidence of immediate benefits to the mother with equally robust evidence of potential short- and long-term risks to the child. Mothers often wonder whether the antibiotics they take affect their child, and this study may provide reassurance that they have only minor effects on babies’ gut microbiomes.”
A handful of previous studies have looked at this question, but they had smaller sample sizes. In the first part of the current study, 28 mother-infant pairs were prospectively included. Twelve of the mothers received antibiotics before the skin incision, and the remaining 16 received them after the umbilical cord was clamped. For this group, a total of 172 infant microbiome samples were collected at 8 different time points after birth, up to one year. The second part of the analysis also included data from two other similar studies for a total of 79 infants.
“Our combined analysis makes this the largest study in this area,” says Sinha. “Additionally, our longitudinal data and in-depth metagenomic sequencing were unprecedented.”
For the samples they collected, the researchers looked at the composition of infants’ gut microbiome and strain variability, as well as the composition of antibiotic resistance genes. They also looked at the composition of bile and short-chain fatty acids. In addition to information about antibiotic use, the researchers also had information about whether the infants were bottle-fed or breastfed.
The results showed that overall, diet had a significant influence on gut microbial diversity, species and bacterial composition at the strain level, as well as bile acid composition. Formula-fed infants had a significantly different overall microbiome profile, with feeding mode explaining 12% of the variation in the overall composition of infants’ gut microbiome during the first six weeks of life. These differences were also reflected in the bile acid profiles in the feces of these infants. Recent research has highlighted the crucial role of the gut microbiome and bile acids in the development of immune disorders later in life. Therefore, these changes in early life can have important long-term consequences. However, further long-term studies are needed to confirm these findings. Antibiotics, in contrast to feeding mode, had only subtle effects on antibiotic resistance genes and strain variability.
“We were surprised that the antibiotics did not drastically change the microbiome, as other research has reported a major impact of antibiotics on the composition of infants’ gut microbiome,” says Sinha. “This is likely due to the fact that it is a single exposure to intravenous antibiotics during birth, as opposed to long-term antibiotic exposure during infancy.”
In their next study, the researchers plan to examine a group of 1,500 mother-child pairs from the Dutch Lifelines NEXT cohort, looking at various health, environmental and nutritional factors during pregnancy and birth, as well as post-birth factors that could affect the pregnancy. the composition of the intestinal microbiome of infants. The researchers plan to follow the babies throughout childhood and adulthood to assess the long-term impact of the babies’ gut microbiome on future health outcomes.
“It is also important to realize that changes in the gut microbiome do not immediately translate into future health outcomes for the child,” says Sinha. “These have yet to be extensively studied in longitudinal studies with longer follow-up time.”
