Predictive value of fecal AI-2 detection for understanding the change of neonatal intestinal flora after usage of broad-spectrum antibiotics

Objective　To investigate the value of detecting the change of autoinducer-2 (AI-2) in stool after usage of antibiotics in monitoring of intestinal flora changes. Methods　Thirty-four infants admitted in Children's Hospital of Chongqing Medical University during Jan. - Jul. 2018 were enrolled in present study, and divided into antibiotic group and control group (17 each). All the subjects were matched according to gestational age, admission age, delivery mode and feeding practices. Children's fecal samples were collected and AI-2 activity was tested by using V. harveyi BB170 bioluminescence assay. The microbial flora in fecal samples were analyzed by 16s rDNA high-throughput sequencing. Results　The relative luminescence value of AI-2 was significantly lower in antibiotic group than that in control group [57.68(50.56, 103.13) vs. 112.63(87.20, 163.57), Z=3.62, P 0.05). In the analysis of flora composition, no significant difference was found at the phylum level between the two groups (P>0.05). While at the genus level, the genus Enterococcus was significantly higher (P=0.002), and the genus Citrobacter was markedly lower in antibiotic group than those in control group (P=0.017). The rest flora composition showed no statistical significance (P>0.05). Conclusions　Using broad-spectrum antibiotics can change the composition of intestinal flora. Flora change at early stage may be associated with the changes of intestinal AI-2. DOI: 10.11855/j.issn.0577-7402.2020.06.07