# Cellular respiration and amino acid metabolism is altered by dietary oligosaccharides in Salmonella with epithelial cell association

## TL;DR

This study shows how different prebiotics affect Salmonella metabolism and epithelial cell interactions during gut infections.

## Contribution

The study reveals prebiotic-specific effects on Salmonella virulence and metabolism in an in vitro model.

## Key findings

- HMO and MOS decreased Salmonella association with epithelial cells.
- MOS treatment increased amino acid metabolism in both host and pathogen cells.
- MOS altered Salmonella respiration toward gut inflammation patterns.

## Abstract

Dietary prebiotic oligosaccharides, complex carbohydrates that support beneficial bacteria, are ubiquitous on marketplace shelves and in people’s diets. Though widely accessible and consumed, little is known about how different prebiotics alter the epithelium and microbes during enteric infections.

Here we show two structurally different prebiotic oligosaccharides, human milk oligosaccharides (HMO) and mannanoligosaccharides (MOS), alter the metabolism of colonic epithelial cells and Salmonella enterica sv. Typhimurium in ways specific to each prebiotic during infection in a focused ‘in vitro’ model.

Initially, HMO and MOS addition decreased S. Typhimurium association with epithelial cells. However, gene expression analysis revealed significantly induced expression of Specific Pathogenicity Island (SPI) 1 (adj. p < 2.0−6) and 2 (adj. p < 3.0−5) with HMO treatment, opposed to increased fimbriae expression (adj.p < 3.0−3) with MOS treatment. Both host and pathogen metabolism were likewise altered with prebiotic addition. MOS treatment induced the expression of genes for amino acid metabolism in both the host cells and in S. Typhimurium, a metabolic shift that was not observed in the HMO treated cells. MOS treatment also altered pathogen-related respiration metabolism in S. Typhimurium toward activity typically seen during gut inflammation.

The regulation of virulence expression in Salmonella from prebiotic treatment was unexpected and suggests prebiotics act in context-dependent ways to potentiate or attenuate enteric activity.