Mode of birth delivery shapes microbiota: Correlation found at age ten

13 Aug 2019 --- Whether a child is born by vaginal delivery or Caesarian section has a major influence on shaping the microbiome, proposes new research in the Journal of Investigative Dermatology. The maturation of skin microbial communities is key to skin health in children, and for the development of the adult immune system. Additionally, the bacterial population of a child’s skin is more similar to that of their mother’s than to a stranger’s.

“To date, research into the maternal influence on her child’s skin microbiome has been mostly limited to a narrow postpartum window in children younger than one year old and fewer studies have explored the maternal relationship with the child’s microflora after infancy,” explains lead investigator Zhe-Xue Quan, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, China. “Therefore, we expanded the scope of our analysis to include sampling from different body sites and direct comparison to the mother of the child in order to provide novel insights.”

The researchers investigated skin microbiota changes in 158 children between the ages of one and ten. The relationship between the skin microbiome and microenvironment, as well as between the microbiota composition of children and mothers was also examined. Samples from the center of the cheek, one-quarter of the length of the forearm from the hand and the center of the calf were taken to compare the microbiota structures between the children and their mothers using 16S rRNA gene amplicon sequencing.

Sample location and age were the main factors determining a child’s bacterial composition.“Our results suggest that the bacterial population on a child’s skin is to a large extent similar to that of their mothers and is affected in the long term by the way they were delivered at birth. One possible explanation is that the developing skin microbiome interacts with the immune system, which may be educated by exposure to microbes during a critical window early in life. It means that microbial colonization runs in parallel with immune system development,” says Professor Quan.

Sample location and age were the main factors determining a child’s bacterial composition, with there being a negative correlation between the abundances of Streptococcus and Granulicatella and age. The amount of most of the children’s bacterial genera was more similar to those of their own mothers than those of unrelated women. Additionally, the facial bacterial composition of ten-year-old children was strongly associated with whether they were born by Caesarian section or vaginal delivery.

“By analyzing the microbial community structure at three very different skin sites of children, we demonstrated that the skin microbiome is strongly impacted by the surrounding microenvironment and that the alpha diversity of the skin microbiome increases during childhood,” he continues.

The skin hosts around ten billion bacterial cells per 1.8 square meters and is the body’s first line of defense. Skin-associated bacteria make up a significant proportion of the human microbiome and interact with the host immune system via numerous pathways, with certain bacteria acting as beneficial microbes or opportunistic pathogens.

Research in the skin microbiome space is growing, and it has been pegged as an area with significant growth potential. Earlier this year, DSM Venturing invested in skin microbiome company S-Biomedic NV, underlining DSM’s interest in the skin microbiome.

The role of early life in the development of a healthy microbiome has also been identified. Earlier this year, a study found that a high-fat diet during pregnancy may contribute to the impairment of the gut barrier. This could lead to metabolic shifts and impede fetal development, with the study suggesting that changes in the maternal gut microbiome may contribute to metabolic changes. 

Other factors such as diet can also shape the microbiome. A recent study found an association between diet quality and microbiome composition in human colonic mucosa. A high-quality diet is linked to more potentially beneficial bacteria, while a low-quality diet is associated with an increase in potentially harmful bacteria. 

By Katherine Durrell