Exam 4 - Lecture 22 Flashcards
what are virulence factors?
molecules (commonly proteins) produced by pathogens that contribute to the pathogenicity of the organism
what are some examples of virulence factors?
- toxins
- adhesions (pili/fimbriae)
- flagella
- immune evasion molecules
what causes Diphtheria? what is its Gram characteristic?
- Corynebacterium diphtheriae
- Gram positive
what is the only virulence factor of C. diphtheriae?
exotoxin
where does exotoxin come from? what does it do?
- C. diphtheriae harbors lysogenized bacteriophages with tox genes.
- the phage produces exotoxin that inhibits protein synthesis and is responsible to pathogenesis
Diphtheriae toxin or ____ toxin is held together by what?
- AB
- disulfide bonds
how do you observe Diphtheria?
observe the pseudomembrane in the throat
what makes the mycobacteria cell wall unusual?
- it’s Gram-positive but does not stain purple
mycobacteria have an “outer membrane” made up of:
mycolic acids
true of false: mycolic acids are very hydrophilic.
false; very hydrophobic
what is the name of the stain used to identify mycobacteria?
- Ziehl-Neelson stain
- Acid fast stain
what is the initial stain of Ziehl -Neelson staining?
Carbol Fuchsin
true or false: Mtb does not produce classic virulence factors.
true, it doesn’t use toxins, secreted enzymes, or adherence factors
what is the major virulence factor of Mtb?
the ability to survive phagocytosis
how does Mtb avoid phagocytosis?
- kills macrophages
- resistant to oxidative killing
- inhibits diffusion of lysosomal cells
