Salmonella Flashcards
Gram stain
Gram negative
Morphology
Rod shaped with peritrichous flagella
Oxygen requirements
Facultatively anaerobic
Habitat
GI tract of all animals, including fish, and reptiles
Antigenic characteristics
-O antigen
-H antigen
-Virulence or capsular: only some have
-Flagella
-Endotoxin
-Pathogenicity islands
-Siderophores
-Stress proteins
-Virulence plasmids
Two main classifications of salmonella
S. bongori and S. Enterica
Human serotypes
-Typhi
-Paratyphi
-Schottmulleri
-Hirschfeldii
-Sendai
Cattle serotypes
Dublin
Swine serotypes
-Cholerasuis
-Typhisuis
Poultry serotypes
-Pullorum
-Gallinarum
Does salmonella ferment lactose
No
Mode of infection
- oral
- Transovarian transmission (ovary to egg in chickens)
- Flies
- Foodborne infections in humans
Predisposing factor for salmonella
Stress!
-Shipping
-Cold
-Overcrowding
-Surgery
etc
Two major sources of infections
-Infected animals
-Asymptomatic carriers
Pathogenesis of intestinal infections
- Colonization of the intestine
- Invasion and damage of the intestinal epithelium
- Stimulation of fluid production and excretion
How does salmonella invade intestinal epithelium
1.Enter the cells through the microvilli or junction complexes
2. Multiply and attach adjacent cells
3. Enter lamina propria and engulfed by macrophages
4. Able to survive and multiply inside phagocytes