1. Spatial Segregation of Virulence Gene Expression during Acute Enteric Infection with Salmonella enterica serovar Typhimurium
Richard C. Laughlin, Leigh A. Knodler, Roula Barhoumi, H. Ross Payne, Jing Wu, Gabriel Gomez, Roberta Pugh,
Sara D. Lawhon, Andreas J. Bäumler, Olivia Steele-Mortimer, L. Garry Adams

2. Salmonella Typhimurium
Gram-negative intracellular bacillus
Enterobacteriaceae family
Non-host specific
World:
1.3 billion cases of enteric salmonellosis each year
3 million deaths
USA:
1.5 million
500 deaths
Recent outbreaks
For every case reported about 38 unreported cases occur

3. Salmonella Typhimurium
Environmental Survival
pH 4 to 8+
Temp 8° to 45°C
Within soil, water, manure, or amoeba
Host Survival
Temp ~37°C
Through alimentary track

4. Salmonella Typhimurium
Found in
Ground beef
Sushi
Sprouts
Pet turtles
Pigs
Chickens
Cows

5. Descriptive Host:Pathogen Interaction
Bovine Model
2 or 8h incubation
Conditionally expressing GFP Salmonella
Fixed and processed for EM or Confocal
Post imaging analysis
Early (2h) and late (8h) cellular interactions
Single cell temporal and spatial distributions

6. Early (2h) Invasion Cytokeratin 8 PinvF-GFP DNA fliC PinvF-GFP Actin
Laughlin et al. mBio 2014 vol5 no1. e

7. Early (2h) Invasion
Laughlin et al. mBio 2014 vol5 no1. e

8. Early Invasion- Host:Pathogen
Laughlin et al. mBio 2014 vol5 no1. e

9. Temporal & Spatial Distribution
Actin
GFP Salmonella
DNA 2h 8h
Distance of PinvF or PssaG positive tissue associated Salmonella to nearest apical surface at 2h or 8h post-infection 8h
Laughlin et al. mBio 2014 vol5 no1. e

10. Summary
Loss of membrane integrity around some intracellular Salmonella including those in extruding epithelial cells.
Robust presence of small membrane vesicles originating from host and pathogen.
Distinct segregation between SPI1 and SPI2 profiles.
SPI1 Salmonella were primarily tissue associated early in infection; predominantly found in epithelium.
SPI2 Salmonella found exclusively in late infection samples within lamina propria.
Laughlin et al. mBio 2014 vol5 no1. e