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Gül E, Bakkeren E, Salazar G, Steiger Y, Abi Younes A, Clerc M, Christen P, Fattinger SA, Nguyen BD, Kiefer P, Slack E, Ackermann M, Vorholt JA, Sunagawa S, Diard M, Hardt WD. The microbiota conditions a gut milieu that selects for wild-type Salmonella Typhimurium virulence. PLoS Biol 2023; 21:e3002253. [PMID: 37651408 PMCID: PMC10499267 DOI: 10.1371/journal.pbio.3002253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/13/2023] [Accepted: 07/13/2023] [Indexed: 09/02/2023] Open
Abstract
Salmonella Typhimurium elicits gut inflammation by the costly expression of HilD-controlled virulence factors. This inflammation alleviates colonization resistance (CR) mediated by the microbiota and thereby promotes pathogen blooms. However, the inflamed gut-milieu can also select for hilD mutants, which cannot elicit or maintain inflammation, therefore causing a loss of the pathogen's virulence. This raises the question of which conditions support the maintenance of virulence in S. Typhimurium. Indeed, it remains unclear why the wild-type hilD allele is dominant among natural isolates. Here, we show that microbiota transfer from uninfected or recovered hosts leads to rapid clearance of hilD mutants that feature attenuated virulence, and thereby contributes to the preservation of the virulent S. Typhimurium genotype. Using mouse models featuring a range of microbiota compositions and antibiotic- or inflammation-inflicted microbiota disruptions, we found that irreversible disruption of the microbiota leads to the accumulation of hilD mutants. In contrast, in models with a transient microbiota disruption, selection for hilD mutants was prevented by the regrowing microbiota community dominated by Lachnospirales and Oscillospirales. Strikingly, even after an irreversible microbiota disruption, microbiota transfer from uninfected donors prevented the rise of hilD mutants. Our results establish that robust S. Typhimurium gut colonization hinges on optimizing its manipulation of the host: A transient and tempered microbiota perturbation is favorable for the pathogen to both flourish in the inflamed gut and also minimize loss of virulence. Moreover, besides conferring CR, the microbiota may have the additional consequence of maintaining costly enteropathogen virulence mechanisms.
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Affiliation(s)
- Ersin Gül
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Erik Bakkeren
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
- Department of Biology, University of Oxford, Oxford, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Guillem Salazar
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
- Institute of Microbiology and Swiss Institute of Bioinformatics, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Yves Steiger
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Andrew Abi Younes
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Melanie Clerc
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Philipp Christen
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Stefan A. Fattinger
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Bidong D. Nguyen
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Patrick Kiefer
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Emma Slack
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
- Institute for Food, Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Martin Ackermann
- Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Department of Environmental Microbiology, Eawag, Duebendorf, Switzerland
| | - Julia A. Vorholt
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Shinichi Sunagawa
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
- Institute of Microbiology and Swiss Institute of Bioinformatics, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Médéric Diard
- Biozentrum, University of Basel, Basel, Switzerland
- Botnar Research Centre for Child Health, Basel, Switzerland
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
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