Acquisition of Gut Flora in Human Infants
The gastrointestinal tract of a normal fetus is sterile. During birth and rapidly thereafter, bacteria from the mother and the surrounding environment colonize the infant's gut. Immediately after vaginal delivery, babies may have bacterial strains derived from the mothers' feces in the upper gastrointestinal tract. Infants born by caesarean section may also be exposed to their mothers' microflora, but the initial exposure is most likely to be from the surrounding environment such as the air, other infants, and the nursing staff, which serve as vectors for transfer. The primary gut flora in infants born by caesarean delivery may be disturbed for up to six months after birth, whereas vaginally born infants take up to one month for their intestinal microflora to be well established. After birth, environmental, oral and cutaneous bacteria are readily transferred from the mother to the infant through suckling, kissing, and caressing. All infants are initially colonized by large numbers of E. coli and streptococci. Within a few days, bacterial numbers reach 108 to 1010 per gram of feces. During the first week of life, these bacteria create a reducing environment favorable for the subsequent bacterial succession of strict anaerobic species mainly belonging to the genera Bifidobacterium, Bacteroides, Clostridium, and Ruminococcus. Breast-fed babies become dominated by bifidobacteria, possibly due to the contents of bifidobacterial growth factors in breast milk. In contrast, the microbiota of formula-fed infants is more diverse, with high numbers of Enterobacteriaceae, enterococci, bifidobacteria, Bacteroides, and clostridia.
Read more about this topic: Gut Flora
Famous quotes containing the words acquisition of, acquisition, gut, flora, human and/or infants:
“Wars and revolutions and battles are due simply and solely to the body and its desires. All wars are undertaken for the acquisition of wealth; and the reason why we have to acquire wealth is the body, because we are slaves in its service.”
—Socrates (469–399 B.C.)
“Wars and revolutions and battles are due simply and solely to the body and its desires. All wars are undertaken for the acquisition of wealth; and the reason why we have to acquire wealth is the body, because we are slaves in its service.”
—Socrates (469–399 B.C.)
“From the gut comes the strut, and where hunger reigns, strength abstains.”
—François Rabelais (1494–1553)
“A man’s interest in a single bluebird is worth more than a complete but dry list of the fauna and flora of a town.”
—Henry David Thoreau (1817–1862)
“But ancient insolence is wont to bear an insolence that has its youth among human miseries, sooner or later, when the fixed time of birth is come.”
—Aeschylus (525–456 B.C.)
“But most thro’ midnight streets I hear
How the youthful Harlots curse
Blasts the new-born Infants tear
And blights with plagues the Marriage hearse”
—William Blake (1757–1827)