Flashcards in deck 9 Deck (61)
which type of virus is commonly associated with pastries?
If a blood culture grows gram + spore forming rods, which two types of bacteria should you immediately think of?
1) Bacillus cereus2) Bacillus anthracis
T/F Most individuals are immune to the toxins released by Diphtheria?
True. We have corynebacteria as part of our normal flora, and since we are vaccinated against it as children, it hardly ever causes problems in the USA.
what type of bacteria is Corynebacterium diptheria?
Gram + rod that releases an exotoxin.
What do high iron levels do to the diphtheria toxin?
High iron levels function as co-repressors of exotoxin production.
How do bacteria make the active diphtheria toxin?
It starts out as a very long chain that is nicked into two parts. Part A=active enzyme, Part B=cell binding. (part B binds and facilitates the entry of Part A)
Once part A of the diphtheria toxin makes it into the cell, what does it do?
It catalyzes this rxn: Product inactivates protein synthesis(A + NAD + EF-2 --> A + N + ADPR-Diphthamide-EF-2)
Where do you usually find staphylococcal enterotoxin A?
It is a common superantigen agent that frequently results in food poisoning.
What causes hemolytic uremic syndrome?
Shiga like toxin
Scarlet fever toxin, staphylococcal enterotoxin A, cholera toxin, shiga like toxin, and diptheria are all examples of what?
Bacteriophage encoded exotoxins
Were does diphtheria usually colonize?
The pharynx, larynx, and nose.
What does the diphtheria toxin do to those individual susceptible to it?
kills epithelial cells and infiltrating PMN'screates an ulcer which is convered with with necrotic exudate forms what is called a pseudo membraneReleases toxin
What is are the classic signs of acute diphtheria toxin?
bull neck appearance with internal pseudomembrane.
what is the major way in which diphtheria kills the patient?
It stops their heart
Does diphtheria effect the blood and lymphatic tissue?
Yes. This is how it kills.
what major problems can diphtheria cause?
1) Fever, vomiting, diarrhea2) Myocarditis (This is how it usually kills)3) polyneuritis (demyelination leading to paralysis of the soft palate)
How do you diagnose someone who has diphtheria?
1) pseudomembrane 2) detection of exotoxin3) bull neck appearance
How do you treat someone with diphtheria?
1) treat with antitoxin 2) use antibiotics (penecillin/erythromycin because it is sensitive to most antibiotics)3) Tracheotomy if needed.
How do you prevent diphtheria?
How often is the DTaP vaccine given?
It is given as a series of 5. 2, 4, 6, 18 months, then at 4-6 years of age. The tetanus vaccination needs to be renewed every 10 years thereafter.
where do you generally find listeria monocytogenes contamination?
cheeses or machinery used to process foods.
T/F listeria monocyogenes can infect a pregnant woman and transverse across the placenta to the fetus?
T/F To help kill listeria monocytogenes, you should give the antibiotic vancomycin?
false. It is an intracellular pathogen so antibiotics do not help kill it off.
Why do you see granulomas with listeria monocytogenes?
It is because the organism escapes the phagosome within the macrophage and so it doesn't become killed. This means that the body tries to wall it off like it does with tuberculosis.
what protein allows listeria monocytogenes to escape the phagosome?
Listeriolysin O. (it is a hemolysin)
why are CD8 cells heavily involved in killing listeria monocytogenes?
it is because it is an intracellular pathogen. This would be presented on MHC I and presented to CD 8 killer cells which would activate the macrophage.
Who do listeria monocytogenes usually infect?
immunocompromised individuals and developing fetuses.
What is listeria monocytogenes major virulance factor?
intracellular survival by escaping the phagosome
What does the protein internalin do?
Its a surface protein that helps listeria with invasion of cells