How does normal flora enter the body?
The gastrointestinal tract of a normal fetus is sterile. During birth and rapidly thereafter, bacteria from the mother and the surrounding environment colonise the infant’s gut. Immediately after vaginal delivery, babies have bacterial strains in the upper gastrointestinal tract derived from the mothers’ feces. Infants born by caesarean section may also be exposed to their mothers’ microflora, but the initial exposure is most likely to be from environmental microbes such as the air, other infants, and the nursing staff which serve as vectors for transfer. The primary gut flora in infants born by cesarean delivery may be disturbed for up to 6 months after birth whereas vaginally born infants take up to 1 month for their intestinal micro flora 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 colonised by large numbers of E. coli and stre
