Characteristics of the Intestinal Microbiota and Metabolism in Infants with Extrauterine Growth Restriction

Objective: Infants with extrauterine growth restriction (EUGR) experience significant postnatal growth restriction in the first week after birth, which indicates a failure of energy absorption. This study aimed to determine the different intestinal microbial species and metabolites between infants with EUGR and those without EUGR. Methods A total of 73 infants hospitalized in a neonatal intensive care unit were enrolled and divided into the EUGR group (n = 50) and the non-EUGR group (n = 23). Fecal samples were collected during hospitalization. Bacterial species and their relative abundance were identified with metagenome sequencing. The metabolites in the feces and blood were identified with an LC-MS–based non-targeted metabolome. Results The intestinal microbiota of the EUGR group contained less Bacteroides vulgatus , Dorea unclassified , Lachnospiraceae bacterium 1_1_57FAA , and Roseburia unclassified compared to that of the non-EUGR group. More importantly, the intestinal microbiota of the EUGR group contained Streptococcus mitis_oralis_pneumoniae , while that of the non-EUGR group did not. Furthermore, KEGG prediction and a correlation analysis identified that the majority of different microbial species higher in the non-EUGR group were related to metabolism. The results of the non-targeted metabolome revealed that several metabolites in the feces and blood were much higher in either group, some of which were related to the different microbial species. Conclusions This study identified several different intestinal microbial species and metabolites in the patients feces and blood, which may provide evidence to identify the biomarkers of infants with EUGR.