STANFORD, Calif., June 26 (UPI) -- U.S. researchers have categorized the hundreds of species of bacteria that colonize a newborn's gastrointestinal track.
The Howard Hughes Medical Institute scientists used a sophisticated genetic analysis of a years worth of baby fecal matter, developing a detailed picture of how bacteria develop in a child's intestinal tract during the first year of life.
Scientists have long known humans carry as many as 400 species of microbes in their intestines, helping digest food and mitigate disease, among other things.
"I don't know what a human would look like without a colonized gut," said Chana Palmer, senior author of the research which was led by Patrick Brown at the Stanford University School of Medicine.
Before birth, the intestinal tract is sterile but babies immediately begin acquiring microbes from the birth canal, their mothers' breast and even human touch, the researchers said.
Within days, a microbial community is established and by adulthood, the body has up to 10 times more microbial cells than human cells.
The study, which tracked the evolution of the microbial ecosystems in 14 healthy, full-term human breast-fed infants, is reported in the journal PLoS Biology.