A preliminary analysis of changes in composition of intestinal microbiota during infancy using polymerase chain reaction-denaturing gradient gel electrophoresis / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the composition of bacteria in the stools of infants and the colonization of intestinal microbiota during infancy.</p><p><b>METHODS</b>Fresh stools were collected from 15 healthy infants at 0, 2, 4, 7, 10, 14, and 28 days and 3, 6, and 12 months after birth. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the composition of intestinal microbiota, perform sequencing of dominant bacteria, and to analyze the changes in the composition of intestinal microbiota during infancy.</p><p><b>RESULTS</b>DGGE fingerprint showed that the composition of intestinal microbiota during infancy changed significantly over time after birth. The cloning and sequencing results indicated that Proteobacteria colonized the earliest, mainly the obligate aerobes Enterobacter and Pseudomonas, followed by the obligate anaerobes (Clostridium hathewayi and Veillonella parvula) and the facultative anaerobe Clostridium ramosum in Firmicutes, and Verrucomicrobia. Actinobacteria colonized the latest, mainly Bifidobacterium, and gradually became dominant bacteria.</p><p><b>CONCLUSIONS</b>During infancy, obligate aerobes colonize the intestinal tract the earliest, followed by obligate anaerobes and facultative anaerobes. Proteobacteria colonizes the earliest, followed by Firmicutes and Verrucomicrobia, and Actinobacteria, mainly Bifidobacterium, colonizes the latest.</p>

Colonization and development of intestinal bifidobacteria in early infancy / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the characteristics of the colonization of 8 species of bifidobacteria by systematically profiling fecal bifidobacterial community in the early life of infants.</p><p><b>METHODS</b>Fresh fecal samples including meconium samples were collected for culture and isolation of fecal bifidobacteria from 16 cases of full-term newborn infants born between March and April 2013 at their life of 2, 4, 7, 10, 14, 28, and 90 days. The isolated fecal bifidobacteria were taxonomically identified to genus and 8 species with PCR analysis.</p><p><b>RESULTS</b>One hundred and fifty-two predominant bifidobacteria strains were detected in the fecal samples, the detection rate of B. breve (22.4%) were the highest. Bifidobacteria were found in the feces of 8% infants 4 days after birth. The colonization rates increased to 54% and 60% at 28 days and 3 months respectively, significantly exceeding the colonization rate at 4 days after birth (P<0.05). Adult-type bifidobacteria B. catenulatum were found in the infants 10 days after birth, and infant-type bifidobacteria B. infantis were found at 14 days after birth, but infant-type bifidobacteria B. infantis were detected at a high level until 3 months after birth. The most tested infants had 2 species or less of bifidobacteria.</p><p><b>CONCLUSIONS</b>Intestinal bifidobacteria in infants might have less diversity in early infancy. Infant-type bifidobacteria appear late, while adult-type bifidobacteria colonize earlier.</p>