Antibiotics administered during labor delay a healthy gut colonization in infants
Roughly one third of pregnant woman carry Group B Streptococcus (GBS) in their gut and vagina. While it is harmless to adults, it may cause serious illness including meningitis and death in a very small portion of infants. In the United States physicians include the testing for GBS as a routine in prenatal care, in Germany the patients have to ask for it. The risk for the baby of becoming ill when the mother is colonized with GBS, is one out of 200. Because of the illnesses high severity, physicians recommend to take antibiotics as a prophylaxis during labor.
The latest research of Jennifer C. Stearns investigated the effect of antibiotic administration during labor on the infants gut microbiome. In their study they compared infants born vaginally with no exposure to antibiotics with infants who were exposed to antibiotics via their mothers and with infants born by C-section. The molecular analysis (16s rRNA) revealed that there is a delay in the expansion of Bifidobacterium over the first twelve weeks and a persistence of Escherichia when the infants were exposed to antibiotics for GBS during labor. Bifidobacterium is one of the first dominant gut colonizers in infants. A longer duration of the antibiotic exposure increased the effect on the Bifidobacterium population, indicating a longer delay in microbiome maturation. Infants born via C-section showed an altered microbiome, including a notable lack of Bacteroidetes, which has already been observed in earlier studies.
An atypical maturation of microbiota early in life may contribute to lifelong changes in the host but details in this early formation stage are rare. As written in the articles in this website, a dysbiosis correlates with various diseases such as obesity, allergies, IBD and colon cancer and many more. As the microbiome and its development are an enormously complex area and research on this topic is still in its infancy, many further studies are necessary to prove direct impacts of early microbiome development on chronic diseases in adulthood.
Prophylactic antibiotic administration is being practiced during labor in 50% of cases (low risk, full term infants) in the United States due to C-Section or GBS. Although antibiotic administration during labor is considered save, the influence on the gut microbiome development of the infant is uncertain.
Nature.com, Stearns et al., 2017