Abstract: Objective　To explore the significance of fecal autoinducer-2 (AI-2) in monitoring the occurrence and recovery of neonatal necrotizing enterocolitis (NEC). Methods　Twelve newborns with NEC, diagnosed between October 2017 to April 2018, were included in the present study (the NEC group, n=12). Another 12 newborns were paired with gestational age, age, way of delivery, way of feeding, use of antibiotics and so on, to the NEC group as control group (n=12). The onset of NEC was defined as acute phase and the recovery phase was recognized from the third day after re-introducing feeding of milk. Fecal samples from control group, NEC acute phase and NEC recovery phase were collected. The AI-2 concentration in feces was detected by biofluorescence assay. The fecal flora was analyzed by 16S rDNA high-throughput sequencing. Results　Intestinal flora in Phylum level, the Bacteroides in the acute phase of NEC was significantly lower than that in the control group (P < 0.05). The Bacteroides abundance of NEC in the recovery phase was further lower than that in the acute phase (P < 0.05). In the generic level, Enterococcus and Bacteroides decreased significantly in acute phase of NEC than that in the control group and the recovery phase of NEC (P < 0.05). There was no significant difference in Shannon index among groups. Relative biofluorescence values of feces AI-2 in acute phase of NEC was lower than those in recovery phase of NEC and control groups (P < 0.05). Conclusion　AI-2 has a strong correlation with the changes of NEC and intestinal flora disorders, which may have potential clinical value in monitoring the occurrence and recovery of NEC.

Key words: 　autoinducer-2;　necrotizing enterocolitis;　intestinal flora;　diversity