title: Culture-independent analysis of fecal microbiota in infants, with special reference to Bifidobacterium species.
abstract: Fecal microbiota of 31 breast-fed, 26 mix-fed, and 11 bottle-fed infants were analyzed by using terminal restriction fragment length polymorphism (T-RFLP), and culture method. We first determined the total and cultivated bacterial counts in infant fecal microbiota. Only approximately 30% of bacteria present in fecal microbiota were cultivable while the remainder was yet-to-be cultured bacteria. Sixty-eight fecal samples were divided into two clusters (I and II) by T-RFLP analysis, and then subdivided into five subclusters (Ia, Ib, IIa, IIb and IIc). There was no clear relationship between clusters and feeding method. A proportion of bifidobacteria was detected in the fecal material by PCR method using species-specific primers. The predominant Bifidobacterium spp. was Bifidobacterium longum longum type (43 samples (63.2%)), followed by B. longum infantis type (23 samples (33.8%)) and B. breve (16 samples (23.5%)). The distribution of Bifidobacterium spp. was similar in the three feeding groups. In contrast, the high incidence of B. breve in cluster I, especially subcluster Ia and B. longum longum type in cluster II, especially subcluster IIa and IIc were characterized by T-RFLP method. Our results showed that the colonization of Bifidobacterium spp. in infant feces correlated with the T-RFLP clusters.
authors.affiliation: Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Center, Wako, Saitama 351-0198, Japan. sakata@jcm.riken.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakata
authors.forename: Toshiki
authors.initials: T
authors.lastname: Tonooka
authors.forename: Shinobu
authors.initials: S
authors.lastname: Ishizeki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takada
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukuyama
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Benno
mesh_terms: D001644:Bifidobacterium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001903:Bottle Feeding; D001942:Breast Feeding; D015169:Colony Count, Microbial; D003470:Culture Media; D005243:Feces / Q000382:microbiology*; D006801:Humans; D007231:Infant, Newborn; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D003470:Culture Media