Microbes: With us since birth

“Okay, I understand that we have bacteria in and on us… making our microbiome. But, how did it get there?”

For those whose mother had a traditional labor, we received our first introduction to the human microbiome at birth.  As we passed through the birth canal, our mothers unknowingly slathered us with lactobacillus-rich bacteria which found our way into our body.  That first coating is scientifically fascinating.  Not only does it use quick-colonizing bacteria as a guard against other bacterias, but it sets the stage in the digestive system for easily processing mother’s milk.  

For those born via cesarean section, the data is not so encouraging since the first bacterial colonizers for those babies were whatever happened to be in the hospital room and on the hospital tools, plus the bacteria on the hands and clothes of the hospital staff and family in the room.  Many of these microbes aren’t necessarily ideal for a newborn, and some can even be resistant to antibiotics (aka, possibly dangerous). Immediately after c-section births, some parents and birthing staff are starting to swab the mother’s vaginal area and rub that on the newborn to get some similar benefits. 

“Children delivered by caesarean section have a different gut microbiota from those born vaginally. Breastfed and formula-fed babies also have distinct microbiotas in their gut. Epidemiological studies suggest that caesarean delivery and formula feeding are associated with an increased risk of obesity and asthma, as well as other conditions, and many researchers think that these effects might be shaped by the gut microbiota.” (DeWeerdt, 2018).

Women and mothers have enough challenges in this world, so don’t stress if you were part of a caesarean birth style. There’s no room for shame here in the Holobiont community. Cesarean births can be medically necessary and very much worth it. After all, beyond the birth experience, an infant’s microbiome is further influenced by countless more factors, including breastfeeding, formula, food, family and friends with infant contact, pets and the overall home environment, medications, and so much more. After just a few years, the gut microbiome is considered fairly stable and resembles the bacteria makeup that they will have at age 17, 37, etc. 

Oh, wait… did you mean how did ancient humans and microbial life get so intertwined in the first place? Great question, holobiont! We’ll tackle that later.

TLDR: Our microbiome is first bestowed upon us through the birth canal, and/or the bacterial community in the room and on the humans during your first few moments of life. After that, breastmilk, environment, pets, family, food, and medicines play a role in shaping- adding to or removing- the bacterial makeup of your microbiome until it is considered stable as a toddler.

Sources and helpful info:

DeWeerdt, S. (2018, March 7). How baby’s first microbes could be crucial to future health. Nature, 555, S18-19.
https://media.nature.com/original/magazine-assets/d41586-018-02480-6/d41586-018-02480-6.pdf 

Howes, L. (2019, September 18). Hospital bacteria can colonize the guts of babies born by C-section. Chemical and Engineering News, 97(37).
https://cen.acs.org/biological-chemistry/microbiome/Hospital-bacteria-colonize-guts-C/97/i37