For a study, a growing number of research employed high-throughput molecular approaches that have rapidly expanded the researcher’s understanding of gut microbial colonization in preterm newborns, whose immaturity and need for intensive therapy may result in a different colonization process. The researchers used 16S rRNA gene-specific sequencing to describe gut microbiota profile in 50 critically unwell children with extremely low birth weight (1200 g) at three different time points throughout the first two months of life. Stool samples were taken at 1 week, 1 month, and 2 months of age. Bacterial community profiling was carried out utilizing universal 16S rRNA gene amplification and 454 pyrosequencing. In the first week of life, the diversity of gut microbiota in preterm newborns was modest, but it grew dramatically during the next two months. Throughout the investigation, facultatively anaerobic bacteria (Staphylococcus spp. and Enterobacteriaceae) dominated the gut microbiota, devoid of microorganisms known to confer pathogen resistance (Bacteroides, Bifidobacterium, and Lactobacillus). Maturity was positively linked with the colonization of Escherichia coli and uncultured Veillionella. Bacterial diversity was substantially higher in infants born to women with chorioamnionitis than in those who did not. Combining a high prevalence and abundance of potentially pathogenic Enterobacteriaceae and Staphylococcaceae with a low prevalence and abundance of colonization resistance provides taxa bifidobacteria, Bacteroides, and lactobacilli, microbial translocation from the gut may result in high infection risk. Furthermore, the researchers’ findings imply that maternal chorioamnionitis may influence the diversity of an infant’s gut microbiota. However, the processes involved are unknown.