Culture-independent analysis of fecal microbiota in infants, with special reference to Bifidobacterium species.
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.
Sakata
Shinji
S
Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Center, Wako, Saitama 351-0198, Japan. sakata@jcm.riken.jp
Tonooka
Toshiki
T
Ishizeki
Shinobu
S
Takada
Masaaki
M
Sakamoto
Mitsuo
M
Fukuyama
Masafumi
M
Benno
Yoshimi
Y
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
D003470:Culture Media