The effects of Escherichia coli Nissle 1917 on the gut microbiota composition in ulcerative colitis patients.

BACKGROUND

Escherichia coli Nissle (EcN) 1917 is a Gram-negative bacterium currently used as probiotic in the management of infectious gastroenteritis and ulcerative colitis (UC). We evaluated the effect of administration of EcN on the composition of the gut microbiota and on intestinal permeability in patients affected by UC.

METHODS

Five patients with stable UC were treated with EcN one pill daily for ten days followed by two pills per day for further twenty days. Fecal samples were collected before the treatment (T0), after ten days (T1) and after one month of treatment (T2). Alpha diversity, microbiota composition and taxonomy were analyzed.

RESULTS

Alpha diversity increased through treatment: Good's coverage index revealed an increase in the number of operational taxonomic units (OTUs) at T2. At phylum taxonomic level, Firmicutes relative abundance decreased at T1 compared to T0. At family level, Clostridiacae relative abundance at T1 was higher than T0 and T2. The T test on gut microbiota variations at species level reveals the variability at the two timepoints (T0 and T2), with significant increase for Actinomyces, Anaerostipes, Bacteroides, Bulleidia, Corynebacterium, Dialister, Enterobacteriaceae, Erysipelotrichaceae, Finegoldia, Granulicatella, Lactobacillaceae, Peptoniphilus, Phascolarctobacterium, Roseburia, Serratia, Veillonellaceae, Veillonella dispar. Furthermore, the administration of EcN improved intestinal permeability, assessed on a CaCO<inf>2</inf> monolayer.

CONCLUSIONS

Treatment with EcN leads to an improvement in the qualitative composition of the gut microbiota in patients affected by UC, in terms of both diversity and taxonomy. These effects are stronger at the end of treatment.