Pyrosequencing-based Molecular Monitoring of the Intestinal Bacterial Colonization in Preterm Infants

Abstract

Objectives: The aim of the study was to investigate the previously unexplored diversity of neonatal intestinal microbiota and monitor early intestinal colonization patterns in Korean preterm infants using high-throughput pyrosequencing technology combined with 16S rDNA-based molecular methods. Subjects and Methods: A total of 46,369 partial 16S rDNA sequences obtained from 30 fecal samples serially taken from 10 very-low-birth weight preterm infants were analyzed. Results: A significant proportion of the molecular species (21.9%) was found to be unclassified. The pathogenic or potentially pathogenic molecular species belonging to the classes Gammaproteobacteria and Bacilli were predominant during the entire observation period. Anaerobic or nonpathogenic molecular species belonging to the class Clostridia (except Clostridium difficile) and phyla Bacteroidetes were ubiquitous even within 72 hours after birth. The proportion of these species increased significantly at 1 month of age. The most ubiquitous and abundant major molecular genera common to all of the postnatal ages were Escherichia, Enterobacter, Enterococcus, Veillonella, Serratia, Staphylococcus, Roseburia, Acinetobacter, Citrobacter, Bacteroides, Faecalibacterium, Blautia, and Streptococcus. Conclusions: The diversity and dynamic nature of intestinal bacterial colonization in very-low-birth weight preterm infants were revealed using pyrosequencing technology. The results of the present pilot study may provide a basis to consider when investigating or interpreting the role of intestinal microbiota in certain preterm infant diseases such as necrotizing enterocolitis or systemic infection.