[ad_1]
Conventional wisdom would make us think that the uterus is a relatively virgin environment, at least as far as germs are concerned. Recent studies on fresh placentas, amniotic fluid and even the first baby poop have always said the opposite.
But what if the isolated microbes in these cases were just contaminants? Now, this seems less likely than ever, researchers taking unprecedented precautions in a recent study to make sure that the microflora they discovered could come from one place.
A group of Australian researchers from Edith Cowan University and the University of Western Australia have applied stringent control measures to isolate bacteria from amniotic fluid and meconium, a fecal material produced by newborns .
"Over the past decade, many studies have detected bacterial DNA in amniotic fluid and first-pbad meconium. [baby’s first poop], questioning the longstanding badumption that the uterus is sterile, "said Lisa Stinson, reproductive biologist, University of Western Australia.
"However, some argue that the results are false positives – contaminants in the reagents used in the badysis of DNA."
This is not meant to denigrate the manufacturers of lab products. But bacteria took billions of years to perfect to survive in conditions that we imagined too hostile to life.
To establish something as controversial as the development of our microbiome even before our birth, no one wants a cheeky parasitic bacterium posing as a red harness.
To ensure that their materials were as clean as possible, Stinson and his team did everything possible, leaving little room for doubt about the presence of bacteria in their samples prior to extraction.
Some of these samples came from 43 pregnant women who delivered by caesarean section. During the delivery procedure, 10 ml of amniotic fluid was carefully collected immediately after incision and transferred to sterilized tubes.
The next day, 50 meconium samples were taken from the newborns of the volunteer, also taken with care to preserve their sterile nature.
The team went to search for traces of bacterial DNA. To make sure that no stray genome is hiding in the reagents, they have given them an enzyme capable of shredding double-stranded DNA fragments.
"Despite these measurements, we still found bacterial DNA in almost all the samples," says Stinson.
Interestingly, the meconium microbiome varied enormously from one newborn to another.The amniotic fluid microbiome contained mostly typical skin bacteria, such as Propionibacterium acnes and staphylococcus species."
Since there is no indication that it is an infection, it is safe to badume that it is a healthy process because bacteria colonize a new human body long before he ventures into the world.
It has long been thought that infants receive their initial dose of microbes as they make their way into the birth cbad. This would mean that a cesarean delivery would not give access to the badl microbiome, which would even lead to swabbing newborns with a "seed" of badl fluid.
But recent research has shown that this belief, and subsequently the badl seeding itself, is not based on solid evidence.
Although our initial environment may influence the selection of bacteria that settle in our body, it seems more obvious than ever that there are already founding members on our skin and in our bowels before we are born.
They are probably not just sitting around turning their thumbs.
"We found that the levels of important immune modulators in meconium and inflammatory mediators in the amniotic fluid varied with the amount and species of bacterial DNA present. Fetal microbiome has the potential to influence the developing fetal immune system, "Stinson says.
It is important to emphasize that, despite the team's efforts, it is impossible to categorically eliminate any contamination.
A species called Pelomonas puraquae was found in virtually all the samples in sufficient quantities that one might wonder if it was an outside intruder. But it was also possible that it was a contaminant from meconium itself, jumping between samples, while ultimately representing the uterine bacteria.
Since the results describe the DNA of the bacteria and not the functional cells, we must also leave the possibility that it is the remains of destroyed invaders.
"Here we have proved that bacterial DNA is present in the uterus, but the next step will be to show if these are alive and constitute a true microbiome," Stinson said.
If this is the case, microbes could really shape our development from the first moments of life.
This research was published in Frontiers in Microbiology.
Source link
