[Colonization and development of intestinal bifidobacteria in early infancy].

OBJECTIVE

To study the characteristics of the colonization of 8 species of bifidobacteria by systematically profiling fecal bifidobacterial community in the early life of infants.

METHODS

Fresh fecal samples including meconium samples were collected for culture and isolation of fecal bifidobacteria from 16 cases of full-term newborn infants born between March and April 2013 at their life of 2, 4, 7, 10, 14, 28, and 90 days. The isolated fecal bifidobacteria were taxonomically identified to genus and 8 species with PCR analysis.

RESULTS

One hundred and fifty-two predominant bifidobacteria strains were detected in the fecal samples, the detection rate of B. breve (22.4%) were the highest. Bifidobacteria were found in the feces of 8% infants 4 days after birth. The colonization rates increased to 54% and 60% at 28 days and 3 months respectively, significantly exceeding the colonization rate at 4 days after birth (P<0.05). Adult-type bifidobacteria B. catenulatum were found in the infants 10 days after birth, and infant-type bifidobacteria B. infantis were found at 14 days after birth, but infant-type bifidobacteria B. infantis were detected at a high level until 3 months after birth. The most tested infants had 2 species or less of bifidobacteria.

CONCLUSIONS

Intestinal bifidobacteria in infants might have less diversity in early infancy. Infant-type bifidobacteria appear late, while adult-type bifidobacteria colonize earlier.