Enterobacteriaceae- II Flashcards
Shigella is an enterobacteriacea that is gram _____ with the shape of_____
gram negative rods
Is shigella an anerobe or aerobe?
A facultative anaerobe.
What is a faculatative aerobe?
A facultative anaerobe is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent.
There are four species of Shigella what are the three main species?
Shigella sonnei
Shigella flexneri
Shigella dysenteriae
What is dysentery?
stool containing blood and mucus
Shigella is the major cause of what?
dysentery
What is the most infection Shigella species in developed countries?
Shigella sonnei
What species of shigella is known for presence in developing countries?
Shigella flexneri
Where is the shigella strain shigella dysentriae most commonly found?
Africa and central America
What age group of people are more frequently infected with Shigella?
children
What is required for transport of shigella? why?
transport media because shigella is acid sensitive.
How is Shigella transported?
spread person to person (fecal - oral route) but it is also in the reservoir of humans.
What is the infectious dosage of Shigella?
low dosage; 10-200 organisms
What are the symptoma of shigella?
- lower abdominal cramps
- tenesmus (straining to defecate)
- pus and blood in stool
- fever
what is tenesmus?
straining to defecate
What is the major virulence in shigella?
shiga toxin
What is the shigella toxin similar to?
EHEC AB5 toxin
The shigella toxin does what?
Binds to Gb3. THe A subunit cleaves the 28 rRNA and inhibit protein synthesis.
Does Shigella contain LPS?
yes
Type 3 secretion Survive where and how?
1) survives in cytoplasm and propelled in to the neighboring cells
2) Survives phagocytosis by inducing apopotosis.
What is one treatment for shigella?
oral rehydration
How is shigella diagnosed?
- stool samples to detect toxin or bacteria
- Media with bile salt.
What are the different Salmonella infections?
1) S. enterica var Typhimurium (S. typhimurium)
2) S. bongori
3) S. enterica var Typhi (s. typhi)
What type of salmonella infection causes the most infections?
S. enterica var Tymphimurium (S. typhimurium)
What type of Salmonella infection is mostly in cold-blooded animals?
Salmonella bongori
What salmonella infection is currently having a food-borne outbreak?
S. enterica var Typhimurium (S. typhimurium).
What salmonella infection is associated with Enteric fever?
Salmonella enterica var typhi (Salmonella typhi)
Which salmonella strain is known to have a reservoir in humans?
Salmonella enterica var Typhi (Salmonella typhi)
What is the infectious dose of S. enterica var Typhi (S. typhi)
Large infectious dose 10^5- 10^9
Salmonella typhimurium has what type of secretion as a virulence factor? which does what?
Type 3 secretion;; injects protein effectors into host cell- actin rearrangement- invasion.
How does the host response play a role in the virulence of Salmonella typhimurium?
Causes inflammation from PAMP recognition by TLRs. It usually causes symptoms but usually clearance of disease.
Some products from the inflammatory response like tetrathionite and ethanolamine do what?
promote Salmonella typhimurium competition against normal flora.
What strains of Salmonella can kill macrophages?
S. typhimurium and S. typhi
Some patients with typoid exhibit what? which causes what?
exhibit genetic changes in immune response possibly promoting carrier state or potential for reinfection
How do salmonella macrophages survive?
T3 secretion and effectors used to promote macrophage uptake, dissemination (spread, carry)
Biofilms of Salmonella promote survival where in the body?
gall bladder
Salmonella typhimurium has normal flora in what animals?
birds and many reptiles.
Klebsiella pneumoniae primary and secondary as well as UTI wound infections are all examples of what?
Enterics; bacteria of the gut or intestines.
Enterobacter occasionally cause what?
UTI as well as sepsis
Serratia, chromobacterium occassionally causes what?
UTI, wound infections and sepsis
