Bacteroidetes/Firmicutes Ratio as an Early Biomarker for NEC Development in Preterm Infants

Neonatal necrotizing enterocolitis (NEC) is a severe intestinal disease potentially linked to gut microbiota dysbiosis. This prospective observational study aimed to evaluate the role of dysbiosis in NEC development.

We included preterm infants with a birth weight <1500 g or gestational age <32 weeks, admitted to Shanghai Children's Hospital from April 9, 2019, to March 30, 2023. Stool samples were prospectively collected and preserved. Cases were infants meeting Bell's stages 2 or 3 criteria for NEC, while controls were matched by gestational age, birth weight, delivery mode, and birth date. Fecal DNA was amplified and pyrosequenced using 16S rRNA gene primers.

We analyzed 370 stool samples from 74 infants (37 NEC cases and 37 controls). Microbial composition in NEC cases differed significantly from controls. Firmicutes abundance began to decline in the case group from the third week of life. At NEC onset, Proteobacteria abundance (p = 0.0001) and the Bacteroidetes/Firmicutes (B/F) ratio (p = 0.006) were significantly higher in cases. A significant increase in the B/F ratio was noted one week before NEC onset (p = 0.02). ROC curve analysis showed an AUC of 0.77; a B/F ratio >0.0439 yielded 81 % specificity and 82 % sensitivity.

An elevated B/F ratio was observed before NEC onset, suggesting it may serve as a predictive biomarker and potential target for NEC prevention.