Alteration of gut microbiota and metabolomics in critically ill patients by sequential feeding: A pilot study

Abstract

Background: Sequential feeding (SF) is a new feeding mode for critically ill patients that involves a combination of continuous feeding (CF) in the beginning, rhythmic feeding in the second stage, and oral feeding in the last stage. In this study, we investigated the influence of SF on gut microbiota and metabolomics in critically ill patients.

Methods: Stool specimens from 20 patients (10 patients with the SF group, 10 patients with the CF group) were collected for full-length 16S ribosomal RNA gene sequencing and untargeted metabolomics analysis.

Results: The proportion of patients with low bacterial diversity (Shannon index < 4) in the SF group was much lower than that in the CF group, but there was no significant difference in the proportions (20% vs 50%, P = .350). The abundances of Actinobacteria/Actinobacteria (at the phylum and class levels), Pseudomonadaceae/Pseudomonas (at the family and genus levels), and Fusobacteria/Fusobacteriaceae/Fusobacteriales/Fusobacteria/Fusobacterium (at the phylum, class, order, family, and genus levels) were all higher in the SF group than in the CF group. Actinobacteria/Actinobacteria (at the phylum and class levels) were the most influential of these gut flora. Retinoic acid and leucine were upregulated in the SF group and were respectively responsible for the intestinal immune network for immunoglobulin A production and the mammalian target of rapamycin signaling pathway in the enriched pathways according to the Kyoto Encyclopedia of Genes and Genomes database classification.

Conclusions: SF could alter gut microbiota and metabolomics in critically ill patients. Because of the small sample size, further study is required.

Keywords: critically ill patients; feeding mode; gut microbiota; metabolomics; sequential feeding.