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<i>Salmonella</i> virulence factors induce amino acid malabsorption in the ileum to promote ecosystem invasion of the large intestine

Abstract:
The gut microbiota produces high concentrations of antimicrobial short-chain fatty acids (SCFAs) that restrict the growth of invading microorganisms. The enteric pathogen Salmonella enterica serovar (S.) Typhimurium triggers inflammation in the large intestine to ultimately reduce microbiota density and bloom, but it is unclear how the pathogen gains a foothold in the homeostatic gut when SCFA-producing commensals are abundant. Here, we show that S. Typhimurium invasion of the ileal mucosa triggers malabsorption of dietary amino acids to produce downstream changes in nutrient availability in the large intestine. In gnotobiotic mice engrafted with a community of 17 human Clostridia isolates, S. Typhimurium virulence factors triggered marked changes in the cecal metabolome, including an elevated abundance of amino acids. In an ex vivo fecal culture model, we found that two of these amino acids, lysine and ornithine, countered SCFA-mediated growth inhibition by restoring S. Typhimurium pH homeostasis through the inducible amino acid decarboxylases CadA and SpeF, respectively. In a mouse model of gastrointestinal infection, S. Typhimurium CadA activity depleted dietary lysine to promote cecal ecosystem invasion in the presence of an intact microbiota. From these findings, we conclude that virulence factor-induced malabsorption of dietary amino acids in the small intestine changes the nutritional environment of the large intestine to provide S. Typhimurium with resources needed to counter growth inhibition by microbiota-derived SCFAs
Publication status:
Published
Peer review status:
Peer reviewed

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Role:
Author
ORCID:
0000-0003-1863-5525
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Institution:
University of Oxford
Role:
Author
ORCID:
0009-0006-2335-5156
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Role:
Author
ORCID:
0009-0000-4156-8549
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Role:
Author
ORCID:
0000-0002-6737-1485


Publisher:
National Academy of Sciences
Journal:
Proceedings of the National Academy of Sciences More from this journal
Volume:
121
Issue:
47
Pages:
e2417232121-e2417232121
Publication date:
2024-11-15
DOI:
EISSN:
1091-6490
ISSN:
0027-8424


Language:
English
Keywords:
Pubs id:
2385679
Local pid:
pubs:2385679
Source identifiers:
W4404411238
Deposit date:
2026-04-23
ARK identifier:
This ORA record was generated from metadata provided by an external service. It has not been edited by the ORA Team.

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