Enumeration, isolation, and identification of bifidobacteria from infant feces

Thirty-three fully breast-fed infants aged between 1 and 12 weeks were screened for bifidobacteria in feces. Bifidobacteria counts in most fecal samples determined both by TPY agar and FISH procedure ranged from 108 to 1011 CFU/g. Three infants did not contain any bifidobacteria in their fecal samples. One child was delivered by caesarean section and the other two by normal vaginal delivery. All bifidobacteria-free infants possessed Gram-positive regular rods as a major group of their fecal flora. These bacteria were identified as clostridia using genus-specific FISH probe. In bifidobacteria-positive samples,B. longum (57.9 % of the samples) was the most frequently found species, followed byB. adolescentis (31.6 %),B. bifidum (21.0 %),B. breve (10.5 %),B. pseudocatenulatum (5.3 %), andB. dentium (5.3 %).