Intestinal Microflora and Atopy Development in Infants during the First Nine Months

The intestinal microflora varies according to the factors such as age, diet and environment. It is debated whether the changes of microbiota after birth are associated with atopic disease. The purpose of this study was to investigate colonization rates of some intestinal microflora during the initial 9 months after birth, and their association with the development of atopy. Methods: Stool specimens were collected at 1, 3, 7 days and at 1, 2, 4, 6, 9 months after birth, and Escherichia coli, Lactobacillus, Bifidobacterium, Staphylococcus aureus were cultured with selective media. Diagnosis for atopy was accomplished via clinical history of atopy, serum total IgE, and skin prick test. Results: By 12 months of age, among 48 infants, 36 (75.0%) were non-atopic while 12 (25.0%) had developed atopy. Although not statistically significant, the intestinal microflora of infants with atopy vs. non-atopy was characterized by being less often colonized with E. coli (12.5% vs. 52.4%; P=0.093) and S. aureus (0% vs. 38.1%; P=0.066) at three days after birth. Colonization rates of E. coli reached 50% after 3 days of birth in non-atopy group whereas this rate was not achieved until after 1 month in the atopy group.