Metagenomic Analysis Reveals Alterations in the Gut Microbiome of Preterm Infants with Extrauterine Growth Restriction

Extrauterine growth restriction (EUGR) is a pervasive clinical issue in preterm infants, affecting neonatal development and their long-term health. This study aimed to characterize the gut microbiome and its derived genes in preterm neonates with EUGR using metagenomic sequencing. Sixty-two preterm infants hospitalized in the neonatal intensive care unit at Guangdong Women and Children Hospital were enrolled in this study. Participants were divided into two groups: the EUGR group (n = 34) and the normal growth group (AGA, n = 28). Fecal samples were collected at one month postnatally. Total bacterial DNA was extracted and sequenced using the Illumina HiSeq X Ten system. Significant differences in the gut microbial community between the EUGR and AGA groups were observed, as evidenced by the Bray-Curtis dissimilarity index. The EUGR group exhibited a notable increase in Klebsiella pneumoniae and Enterococcus faecalis, along with a significant decrease in Streptococcus raffinosi, Rothia mucilaginosa, Parabacteroides merdae and Eggerthella lenta compared to the AGA group. Functional annotation of metagenomic genes identified 415 genes with significantly different relative abundances between the groups. A classification model incorporating five discriminatory genes achieved effective separation of EUGR from AGA infants. Additionally, the EUGR group exhibited a higher relative abundance of antibiotic resistance genes. This study elucidates the alterations in the gut microbiome and its derived genes in preterm neonates with EUGR. These findings provide new insights into the potential microbial signatures associated with impaired growth, although further mechanistic studies are needed to clarify causal relationships.