ABSTRACT
Objective To investigate the characteristics of intestinal flora in infants with different feeding patterns.Methods Sixty-two cases of health infants(30-120 d)were divided into 4 groups according to their feeding patterns:breast feeding,imported powder milk feeding,domestic powder milk feeding and mixed feeding.Samples of their fresh feces in each group were collected and divided into sections equally:the bifidobacteria were isolated in anaerobic box and the number was counted for one section;for the other section,total DNA of intestinal flora was extracted and enterobacterial repetitive intergenic consensus (ERIC) fingerprints were amplified with the method of ERIC-PCR.After that,the specific bands observed in different groups were cloned and sequenced and alignmented.Results The colonies of bifidobacteria were more in breast feeding and mixed feeding groups[(9.10 ± 1.33) cfu/g;(8.62 ± 1.35) cfu/g]than those in domestic powder milk feeding and imported powder milk feeding groups[(7.62 ± 1.22) cfu/g;(7.32 ± 0.80) cfu/g,t =3.23,P ＜ 0.05];while there was no significant difference between breast feeding and mixed feeding groups,and between 2 powder milk feeding groups.Two specific bands were found from the ERIC fingerprints (A:1 100 bp mainly in breast feeding,domestic powder milk feeding and mixed feeding groups;B:1 000 bp mainly in imported powder milk feeding group).Sequencing and analysis of Basic Local Alignment Search Tool showed that homologous bacteria of A and B fragments were bifidobacterium longum.The encoding protein of A fragments might be related to the enzymes of carbohydrate metabolism,and B fragments were related to the enzymes of protein metabolism.Conclusions The colonies of bifidobacteria in intestinal tract are more in breast feeding and mixed feeding infants than those in formula feeding groups.The distribution of intestinal flora in domestic powder milk feeding infants is more similar to that of the breast feeding infants.