Shigella Flashcards
Do we talk about epidemics like in the case of salmonella?
No there’s more sporadic cases
What disease do they cause?
Acute infectious inflammatory colitis or bacillary dysentery
How it is transmitted?
- by ingestion (flies can help transporting bacteria from food to food)
- fecal oral route since there is a continuous excretion of bacteria for 2 to 3 months after treatment.
Who are the reservoir?
Humans
What is the infectious dose?
It is very small like that of salmonella enteriditis
What is the target age group?
Less than 5 years old
What do they produce?
Shigatoxin encoded by chromosomal genes, and proteins responsible for invasiveness
Does it resist the acidity of the stomach? Where do they go?
Bacteria resist the acidity of the stomach and go to the colon
What do they cause in the colon?
Inflammation in the colon
Which immune cells are recruited? Which cells are destroyed?
PMN
RBCs
Which cells are the target of shigatoxin? How does it block protein synthesis?
Endothelial cells
The toxin blocks proteins synthesis by removing the adenine nucleotides, leading to necrosis.
To what resembles the colitis?
It resembles the pseudomembrane because there is necrosis with the release of leukocyte and too much hemolysis
What are you manifestations?
Fever (very high in children only and can lead to seizures). It is caused by the production of cytokines.
Dysentery which is frequent: passage of small quantity of stool with tenesmus (forcing to defecate). The quality of stool ranges from watery, mucoid to bloody dysentery.
Protein malnutrition in children due to the Shigatoxin
No bacteremia except in AIDS patients
Which preventions should be taken in consideration?
Proper hygiene and isolation
From where the specimen is taken?
From the stool
