This study investigates the succession of bacterial communities in the intestines of two healthy neonates over more than 10 months using 16S ribosomal DNA (rDNA) diversity analysis through PCR and denaturing gradient gel electrophoresis (DGGE). The research combines DGGE profiles with 16S rDNA sequence analysis to monitor the dynamic changes in bacterial colonization. The study found that the bacterial communities in the infants' intestines rapidly colonized after birth, with initial simplicity that became more complex over time. Key bacterial types identified included Bifidobacterium, Ruminococcus, Enterococcus, Clostridium, and Enterobacter. The study also revealed that 19 out of 34 cloned rDNA sequences did not match known bacteria or sequences in databases, indicating the presence of novel bacterial species. The findings highlight the utility of PCR-DGGE and 16S rDNA sequence analysis in understanding the complex dynamics of bacterial colonization in the infant gut ecosystem.This study investigates the succession of bacterial communities in the intestines of two healthy neonates over more than 10 months using 16S ribosomal DNA (rDNA) diversity analysis through PCR and denaturing gradient gel electrophoresis (DGGE). The research combines DGGE profiles with 16S rDNA sequence analysis to monitor the dynamic changes in bacterial colonization. The study found that the bacterial communities in the infants' intestines rapidly colonized after birth, with initial simplicity that became more complex over time. Key bacterial types identified included Bifidobacterium, Ruminococcus, Enterococcus, Clostridium, and Enterobacter. The study also revealed that 19 out of 34 cloned rDNA sequences did not match known bacteria or sequences in databases, indicating the presence of novel bacterial species. The findings highlight the utility of PCR-DGGE and 16S rDNA sequence analysis in understanding the complex dynamics of bacterial colonization in the infant gut ecosystem.