IRA FLATOW: Our microbiome is a delicate balance. Diet, place, genetics– they can all affect our individualized bacterial communities. But just how far back does that microbial mix start to develop? A group of researchers say, well, it happens the second you’re born. Babies born through C-section miss out on the bacteria usually picked up from the birth canal. The scientists swabbed these C-section babies with maternal microbes to see if they could restore their microbiomes. And the results were published in the journal Nature Medicine.

My next guest is an author on those results. Maria Gloria Bello is associate professor in the human microbiome program at New York University. I should have just called you Dominguez-Bello. Thank you for–

MARIA GLORIA DOMINGUEZ-BELLO: Thank you for having me.

IRA FLATOW: Thank you for taking time to be with us today.

Tell us it tell us about this. You conducted a small study. How is the microbial profile of a baby born through a C-section different from the one through vaginal birth?

MARIA GLORIA DOMINGUEZ-BELLO: So if you expose a baby to vaginal fluids, the baby will pick up bacteria from the birth canal of the mother. And these bacteria will flourish in different sites of the baby. And that happened both in vaginally-delivered babies of our study, but also when we exposed the C-section-born babies to a gauze that was kept in the birth canal, before the baby was taken out.

IRA FLATOW: And how did you swab the baby? What was that like?

MARIA GLORIA DOMINGUEZ-BELLO: Well, we made it kind of artisanal tampon with a sterile gauze. We folded gauze as a fan, and then in half, and inserted it with a sterile solution. And then we took it out and waited. You know, we put it in a sterile container. Waited until the doctor took the baby out through the incision.

And the first thing we did after– within the first two minutes, after they cut the umbilical, we swabbed the baby. First mouth, and then the face, and rest of the body.

IRA FLATOW: And how close could you get to the kind of bacteria that would happen in a vaginal birth?

MARIA GLORIA DOMINGUEZ-BELLO: Well, we didn’t restore completely. We achieved partial restoration. I don’t know if we’ll ever restore completely, because labor, in the shortest scenarios, take one-to-two hours. And in the worst scenarios, 18. And those– after the mom breaks waters, they baby gets exposed. And labor takes at least a few hours. So and our procedure is just seconds.

So I think– and on the other hand, of course, we are not recapitulating labor. But we want to study, you know, by at least partially restoring the microbiome, can we also restore health? There are some diseases associated with being born by C-section, or early antibiotics. Anything that impacts the microbes very early seem to have an increased risk in some of the diseases of the immune system.

IRA FLATOW: OK. Is it possible to follow these babies in your study to see how they develop?

MARIA GLORIA DOMINGUEZ-BELLO: Well we are follow them for one year. This paper was only for the first month. And we are follow them for a year. Many more babies– 84 so far. But the study would still be microbiological. To do the clinical study and measure health, we need a randomized design, much bigger study of probably thousands of kids. And follow them for at least three years, and then measure obesity, and if possible, asthma, allergies. So it’s a huge study, very expensive one. We are putting together a proposal, but we don’t know where we– whether we will get the money.

IRA FLATOW: I’m Ira Flatow. This is Science Friday from PRI– Public Radio International– talking with Maria Gloria Dominguez-Bello about this is really interesting work on C-section microbiome.

You also– let’s talk about the gut microbes, the fecal microbes, of the C-section babies. Did they differ as much?

MARIA GLORIA DOMINGUEZ-BELLO: When a C-section baby’s born and is not exposed to vaginal fluids, what they pick up is skin-like bacteria– human skin. We did a study swabbing the operating room, which normally– is normally incredibly clean. You know, the floors, the handles. But there are some sites, like up on the walls of the operating room– the ventilation grids, the top of the huge lamps that the surgeons have, if you swab there, there is some dust.

We did studies of that dust. And we demonstrated there is skin flakes there. And those flakes have bacteria. So we think the built environment is seeding the newborn that is born by C-section.

IRA FLATOW: So the baby is getting the microbiome of the room, instead of the mother?

MARIA GLORIA DOMINGUEZ-BELLO: Yes.

IRA FLATOW: Oh, is that interesting.

MARIA GLORIA DOMINGUEZ-BELLO: The mother is probably the least source, because she’s below. Gravity plays against her transmission. There are all the doctors, nurses are shedding. And also the air. You know, the air contains the previous patients skin flakes, the cleaner team. Who knows? It’s a collective of human skin that is maintained in the operating room.

So you know, I think mammals are born through a birth canal that is loaded with bacteria that are very relevant to milk. And then all mammals drink milk. This is an adapted. This is not by chance. So I think we still don’t know what are the health consequences, but it sounds like adaptive. And we– you know, every time you cheat nature, there seems to be a collateral cost that we pay. And we are mammals. We cannot forget that. So we should restore exposure.

IRA FLATOW: You know, I’d heard a while back that breastfeeding– one of the benefits of breastfeeding was not just that your mother’s milk, which is very important, but that the suckling– the baby is getting the microbiome off the mom’s skin as it breast feeds.

MARIA GLORIA DOMINGUEZ-BELLO: Absolutely. And you know what? The baby– the areola of the mom that had a baby born vaginally has vaginal bacteria. The baby– after the mom inoculates the baby, or seeds the baby, the mouth of the baby comes to the areola and seeds the areola of the mother. And milk has components that are completely resistant to digestion by the baby. But they are– nature has them to select bacteria that lives in the intestine of the baby.

So milk has indigestible components. It makes sense only in the view of feeding microbes of the baby– the good microbes that are all ultimately from maternal origin.

IRA FLATOW: Wow. This microbiome is so fascinating. It’s something we love to talk about. And I want to thank you for taking time to talk with us today and bringing this news to us.

MARIA GLORIA DOMINGUEZ-BELLO: Thank you so much. it’s a pleasure to be there.

IRA FLATOW: Dr. Maria Gloria Dominguez-Bello is an associate professor in the Human Microbiome Program at New York University.

Copyright © 2016 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of ScienceFriday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies.