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

Sequential versus continuous feeding and its effect on the gut microbiota in critically ill patients: A randomized controlled trial

BACKGROUND

Gut microbiota disturbance may worsen critical illnesses and is responsible for the progression of multiple organ dysfunction syndrome. In our previous study, there was a trend towards a higher α-diversity of the gut microbiota in sequential feeding (SF) than in continuous feeding (CF) for critically ill patients. We designed this non-blinded, randomized controlled study to confirm these results.

METHODS

All the enrolled patients received continuous feeding in the beginning. After achieving ≥80 % of the nutrition target calories (25-30 kcal/kg/d), the patients were randomized into the SF group or the CF group. In the SF group, continuous feeding was changed into intermittent feeding. The total daily dosage of enteral nutrition was equally distributed during three periods at 7-9:00, 11-13:00 and 17-19:00. After 7 days of randomization, fresh stool and serum were collected for 16S rRNA gene sequencing and untargeted metabolomics analysis respectively. Meanwhile, routine blood test indicators and metabolic indicators were recorded.

RESULTS

Finally, data from 65 patients in the SF group and 69 patients in the CF group were used for intention-to-treat analysis. There was no difference in the Shannon index between the SF group and CF group [2.5 (1.7-3.4) vs. 2.6 (1.5-3.5), P = 0.934]. However, at the genus level, the abundances of Erysipelotrichaceae_UCG-003 and Howardella increased in the SF group. Some metabolic indicators (the albumin level, total cholesterol level and total bile acid level) and the increases in lymphocyte counts in the SF group were different from those in the CF group (P < 0.05). In untargeted metabolomic analysis, 58 differentially abundant metabolites between the two groups were found. The pathway with the highest enrichment factors was primary bile acid biosynthesis according to the Kyoto Encyclopedia of Genes and Genomes Database classification. Regarding adverse events, the gut tolerance, average glucose and incidence of hyperglycemia and hypoglycemia were similar between the SF group and CF group. The mortality rate in the SF group was lower than that in the CF group, but there was no statistical difference (9.2 % vs. 13.0 %, P = 0.484).

CONCLUSION

SF did not increase the diversity of gut microbiota in critically ill patients. However, it did alter the abundances of some gut microbes and affect some metabolites. Its clinical significance requires further exploration. In addition, the gut tolerance and safety of SF were similar to that of CF.

TRIAL REGISTRATION

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CLINICALTRIALS

gov, registration number NCT04443335. Registered 21 June, 2020.

Effect of Enteral Nutrition on the Intestinal Microbiome and Risk of Death in Ischemic Stroke Patients

BACKGROUND

Studies have shown that the intestinal microbiome of stroke patients is significantly altered and that the degree of microbiota disturbance correlates with prognosis. Enteral nutrition can reshape the intestinal microbiome and is important for stroke patients with dysphagia. We aimed to describe the intestinal microbiome in patients with ischemic cerebral infarction receiving standard enteral nutrition.

METHODS

First, 17 healthy controls (HC), 54 stroke patients with oral feeding (ON), and 50 stroke patients with enteral nutrition (EN) were matched to investigate the changes in the intestinal microbiota with enteral nutrition in the first week after admission and dynamic changes in the EN group in the second week. Second, we investigated the relationship between the intestinal microbiome and clinical characteristics in a larger sample of participants receiving enteral nutrition (n=147). Survival analysis was performed using Cox proportional hazards regression. The composition and structure of the intestinal microbiota were analyzed by 16S rRNA sequencing.

RESULTS

Compared with the HC and ON groups, patients with enteral nutrition exhibited significantly different compositions of the intestinal microbiota in the first week, including enrichment of the opportunistic pathogen Enterococcus and depletion of bacteria such as Lachnospiraceae, and Ruminococcus, which were further depleted in the second week. An increase in Parvimonas and Comamonas abundances was associated with an increased risk of 180-day mortality.

CONCLUSIONS

The intestinal microbiota in ischemic stroke patients receiving enteral nutrition is significantly altered, and specific strains of bacteria may be associated with prognosis and clinical indicators. This article is protected by copyright. All rights reserved.