Salmonella, Shigella, and Yersinia are able to:
Produce type III secretion systems
•Introduce proteins into host cells
•Inhibit phagocytosis
•Rearrange the cytoskeletons of eukaryotic cells
•Induce apoptosis
Eggs and poultry are common sources of salmonella and lead to:
Salmonellosis and typhoid fever
The process of salmonellosis 1-3
- Salmonella attaches via adhesion
- To cells lining the small intestine.
- Salmonella triggers endocytosis.
once in the GI tract, they multiply w/in endocytic vesicle.
in step 4 After Salmonella kills the host in the GI tract the effect that occur are:
induces fever, cramps, and diarrhea
Step 5 what happens when salmonella enters the bloodstream?
it can infect tissues throughout your body causing meningitis and endocarditis
Characteristics of salmonella
Bacilli are rod-shaped and have flagella all around.
uses a needle-like structure to inject bacteria in the host cell
Infected cells release pro-inflammatory cytokines causing an inflammatory response.
When salmonella travels through the GI tract.
Life-threatening fever that can lead to death.
Typhoid
Typhoid fever is caused by
Salmonella typhi member of the Enterobacteriaceae family.
Pathogenesis of Shigella
- Using a type III secretion system (TSS),
- injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole.
- It escapes rapidly from the vacuole, replicates within the cytosol, and spreads from cell to cell.
Salmonella Typhoid
•Caused by Salmonella enterica
•Humans are the only host
•Carriers are often asymptomatic
•Bacteria ingested in contaminated food or water.
Salmonella Typhoid fever
•Bacteria pass through intestines to various organs replicates in the macrophage
•Causes gastroenteritis, bacteremia, and peritonitis
Shigella
-Enterotoxin
-Non-motile
-Part of the Enterobacteriaceae family,
- gram-negative rod-shaped pathogenic bacteria
- They are non-motile, non-encapsulated, and facultative anaerobes that do not ferment lactose, or do so slowly
Process Shigella 1
Shigella attaches to the epithelial cells of the colon.
Process Shigella 2
Shigella triggers endocytosis.
Nucleus
Epithelial cell
Process Shigella 3
Shigella multiplies in the cytosol.
Process Shigella 4
Shigella invades neighboring epithelial cells, thus avoiding immune defenses. (Actin fibers)
Process Shigella 5
An Abscess forms as epithelial cells are killed by the infection. (Mucosal abscess)
Process Shigella 6
Blood vessel
Shigella that enters the blood is quickly phagocytized and destroyed. No bacteremia. Phagocyte