[Dynamic changes of intestinal 16S rDNA metagenome in 5 infants].

Objective: To investigate the dynamic changes of intestinal 16S rDNA metagenome in healthy infants.

Methods: Seventeen fecal samples were collected at ages of 3 days, 1 month, 6 months and 1 year in 5 infants. Total bacterial DNAs were extracted and submitted high throughout sequencing on the V6 viable region of 16S rDNA. Tags and Operational Taxonomic Units (OTU) were then obtained and analysis of taxonomy, abundance and alpha diversity were performed.

Results: In total 2,190.66 Mbp raw data in 17 samples were produced. The OTU numbers ranged from 36 to 308. The dominate phylum included Proteobacteria, Firmicutes and Bacteroidetes and Actinobacteria. The bacterial families>1% increased from only 2-4 per sample on day 3 to 7 at 1 or 6 months, 10 at 12 months. The average npShannon and Simpson index on day 3, at 1 month, 6 months and 1 year were 1.117, 1.460, 2.088, 2.50 and 0.443, 0.408, 0.229, 0.143 respectively.

Conclusions: Infants' intestines harbor abounding bacterial genomes. Distinct individual differences exist in infants in terms of intestinal bacterial abundance and composition. The abundance and diversity of gut bacteria increase over time.