# Microbiota outgrowth by Salmonella

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $380,714

## Abstract

Project Summary
Our intestine is host to a complex microbial community, the gut microbiota, which is dominated by obligate
anaerobic bacteria belonging to the classes Clostridia and Bacteroidia. It is well established that a disruption of
the gut microbiota by antibiotic treatment leads to an expansion of facultative anaerobic Enterobacteriaceae,
including pathogens, such as Salmonella enterica serovar Typhimurium (S. Typhimurium), however, the
underlying mechanisms are just beginning to be worked out. Importantly, it is not known whether S.
Typhimurium expands and/or triggers changes in the microbiota composition in the absence of antibiotic
treatment. Our long-range goal is to elucidate molecular mechanisms that control the balance between the
pathogen, the host and its gut microbiota. The objectives of this application are to study the mechanisms that
enable the pathogen to gain an edge over competing bacteria during intestinal inflammation. Our central
hypothesis is that in the absence of antibiotic treatment, S. Typhimurium virulence factors trigger host
responses that lead to a depletion of butyrate-producing Clostridia from the gut-associated microbial
community, which in turn increases oxygenation of colonocytes, thereby driving a cytochrome bd-II oxidase-
dependent pathogen expansion in the gut lumen. We will test different aspects of our hypothesis and
accomplish the objectives of this application using the logical and innovative approach outlined in the following
specific aims: Specific Aim 1: Determine how S. Typhimurium depletes Clostridia during colitis. Specific Aim 2:
Determine how Clostridia depletion drives S. Typhimurium growth during colitis. Specific Aim 3: Determine
whether respiration drives S. Typhimurium transmission. It is our expectation that successful completion of the
proposed experiments will usher in important conceptual advances in understanding the mechanisms
underlying pathogen expansion during S. Typhimurium-induced gastroenteritis. This paradigm-shifting work will
be significant because it will have wide appeal among researchers interested in microbial pathogenesis and
the contribution of host-associated microbial communities to health and disease.

## Key facts

- **NIH application ID:** 9912715
- **Project number:** 5R01AI096528-10
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Andreas J Baumler
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $380,714
- **Award type:** 5
- **Project period:** 2011-05-01 → 2021-07-09

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9912715

## Citation

> US National Institutes of Health, RePORTER application 9912715, Microbiota outgrowth by Salmonella (5R01AI096528-10). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9912715. Licensed CC0.

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