Interplay between chemotaxis, quorum sensing, and metabolism regulates Escherichia coli-Salmonella Typhimurium interactions in vivo


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Date

2025-05-02

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Motile bacteria use chemotaxis to navigate complex environments like the mammalian gut. These bacteria sense a range of chemoeffector molecules, which can either be of nutritional value or provide a cue for the niche best suited for their survival and growth. One such cue molecule is the intra- and interspecies quorum sensing signaling molecule, autoinducer-2 (AI-2). Apart from controlling collective behavior of Escherichia coli, chemotaxis towards AI-2 contributes to its ability to colonize the murine gut. However, the impact of AI-2-dependent niche occupation by E. coli on interspecies interactions in vivo is not fully understood. Using the C57BL/6J mouse infection model, we show that chemotaxis towards AI-2 contributes to nutrient competition and thereby affects colonization resistance conferred by E. coli against the enteric pathogen Salmonella enterica serovar Typhimurium (S. Tm). Like E. coli, S. Tm also relies on chemotaxis, albeit not towards AI-2, to compete against residing E. coli in a gut inflammation-dependent manner. Finally, utilizing a barcoded S. Tm mutant pool, we investigated the impact of AI-2 signaling in E. coli on S. Tm’s carbohydrate utilization and central metabolism. Interestingly, AI-2-dependent niche colonization by E. coli was highly specific, impacting only a limited number of S. Tm mutants at distinct time points during infection. Notably, it significantly altered the fitness of mutants deficient in mannose utilization (ΔmanA, early stage infection) and, to a lesser extent, fumarate respiration (ΔdcuABC, late stage infection). The role of quorum sensing and chemotaxis in metabolic competition among bacteria remains largely unexplored. Here, we provide initial evidence that AI-2-dependent nutrient competition occurs between S. Tm and E. coli at specific time points during infection. These findings represent a crucial step toward understanding how bacteria navigate the gastrointestinal tract and engage in targeted nutrient competition within this complex three-dimensional environment.

Publication status

published

Editor

Book title

Volume

21 (5)

Pages / Article No.

Publisher

PLOS

Event

Edition / version

Methods

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Date created

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Organisational unit

03713 - Sauer, Uwe / Sauer, Uwe check_circle
03589 - Hardt, Wolf-Dietrich / Hardt, Wolf-Dietrich check_circle

Notes

Funding

192567 - Mechanisms controlling the Salmonella Typhimurium gut infection (SNF)
-180575 - NCCR Microbiomes SNF (SNF)

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