Objective In order to know how intestinal Bifidobacteria community could be built in the infants and whether the environmental factors could affect them, the present study was conducted to characterizethe species composition and trace the quantitative changes of intestinal Bifidobacteria of the infants in their early stages with non-culture dependent molecular method. The possible association of Bifidobacteria community of the infants with their health was also discussed. Methods Total 16 of full-term newborn infants born between March and April 2013 were recruited for the present study. Fecal samples were collected from them at 1 day, 2 days, 4 days, 7 days, 10 days, 14 days, 28 days, 3 months, 6 months and 1 year after birth. Real-time fluorescent quantitative PCR with genus and species specific premiers was used to detect Bifidobacteria and 8 predominate species in human intestine qualitatively and quantitatively present in these collected fecal samples. Results Total 136 fecal sample were collected and Bifidobacteria were detected from 93.4% (127/136) of them with the concentration of 1.0×10 5 to 1.0×10 11 CFU/g. Bifidobacteria were found in 83.3% of the fecal samples collected from the first day after birth with more than about 10 5 CFU/g. However, Bifidobacteria were detected relative low until 14 days and were taxonomically belonged only to one or two species. Bifidobacteria were found in almost 100% of the fecal samples
