The organs are far from sterile, whole pathways are very close, there is a lot of pushing beyond control which uses sort of same muscles... it doesn't mean every natural baby is born with big poop on their head (mine weren't), but these transfers do happen. You don't need that many bacteria to make it work, infant's intestines are a sterile place at the beginning so not much competition and food for them starts coming soon.
The digestive system is supposed to be fully sandboxed from the host. Topologically it is as exoneous to your body as your skin and the sandboxing is necessary for your bacteria to not digest yourself.
I would appreciate references on permeability mechanisms allowing for bacteria movement inside the body, on healthly humans.
I mean there is a digestive system to human blood interface but I doubt it allow bacteria/archae/parasites/shrooms/atypical single celled eukaryotes to cross it.
(little known but ~30% of your microbes are not bacteria but archae and withouth those we would not fart)
Did you read the comment you are responding to as saying bacterial travel through the intestinal wall, through the vagina, and into the fetus? It seems like it, but that isn't at all what op said.
The bacterial transfer happens after the placenta has broken and the baby is being pushed out of the vagina. The vaginal opening and anus are inches away. The woman is bearing down to push out the baby and there can be discharges from the anus. Even if that doesn't happen, the area around the anus isn't entirely antiseptic.
of course contamination can happen once the baby it out of the mother body. I was refuting the intra-body contamination thesis.
cf: > The organs are far from sterile, whole pathways are very close
That does not imply intra-body transfer, though. It’s exactly what it says. The digestive organs and the vaginal canal are not sterile, and their pathways converge at the bottom end. Seems pretty straightforward from the rest of the comment that, once the amniotic sac breaks it’s a bacterial slip all the way out, with a surprise at the end.
That bears repeating. One of the grossest things I've ever witnessed (which wasn't something dead) was my son immediately after he was born. I was impressed.
