[Structure of preschoolers intestinal Bifidobacteria and its relationship with milk consumption]

To determine the population structure of intestinal Bifidobacteria in preschool children, and evaluate its relationship with milk consumption.

The study was performed among 200 healthy children aged 2 to 6 in a kindergarten, Chengdu. Half of the children were female. The information of their milk consumption was collected through questionnaire finished by their parents. The levels of Bifidobacterium and 8 Bifidobacterium species in the subject feces were analyzed by real-time fluorescence quantitative PCR. The differences between the population structures of intestinal Bifidobacteria in children with different milk consumption were compared.

The detection rate of Bifidobacteria in the feces of the children was 100%, and the bacterial amount was(9.33±0.54) log_(10 )CFU/g. In comparison with the group whose daily milk consumption was less than 300 mL, the detection rate of B. breve(88.9% vs. 78.4%, χ~2=4.039, P=0.044), the amount of B. breve and B. infantis [(7.35±1.25) log_(10 )CFU/g vs.(6.91±1.32) log_(10 )CFU/g, t=-2.096, P=0.038;(7.36±1.35) log_(10 )CFU/g vs.(6.68±1.45) log_(10 )CFU/g, t=-2.412, P=0.018]were higher in the group whose daily milk consumption was no less than 300 mL.

The detection rate of Bifidobacteria is 100% in the 200 preschool children of Chengdu. B. catenulatum, B. longum and B. breve are believed to be major bifidobacterial species in children intestinal microbiota. The study manifests the association between milk consumption and B. breve or B. infantis engraftment.