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26 Cards in this Set
- Front
- Back
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Pathogen that causes DIPHTHERIA
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Corynebacterium diphtheriae
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Pathogen that causes TETANUS
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Clostridium tetani
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Pathogen that causes CHOLERA
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Vibrio cholerae
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Pathogen that causes BOTULISM
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Clostridium botulinum
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Corynebacterium:
Gram? Shape? Spores? |
C. diphtheriae
Gram positive non-spore forming rods |
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C. diphteriae
(an)aerobic? catalase? motility? |
C. diphtheriae
aerobic catalase-positive non-motile |
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Selective medium for C. diphtheriae
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tellurite agar
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Are diphtheroids ever normal flora?
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Yes: on the skin, nasopharynx, etc.
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Major virulence factor of C. diphtheria
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diphtheria toxin
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diphtheria toxin genes are carried on...
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bacteriophage, beta-Tox
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expression of diphtheria toxin genes is controlled by ...
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Fe availability via DtxR
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Mechanism of C. diphtheriae toxin
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blocks protein synthesis and kills cells
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Dphtheria toxin is what type of toxin?
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AB subunit exotoxin
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function of B subunit in AB exotoxin
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binds to specific glycoprotein receptor, heparin-binding epidermal GF on epitherlial cell surface
facilitates translocation of A subunit across target cell membrane |
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function of A subunit in AB exotoxin
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active subunit
ADP-ribosylase irreversibly blocks protein synthesis --> cytotoxic |
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diphthamide residue =
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modified histidine found ONLY in EF2 in eukaryotic cells
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pathogenesis of C. diphtheriae:
reservoir transmission attachment site in host |
reservoir = human carriers, on skin or nasopharynx
transmission = aerosol route, sometimes fomites attach to epithelial cells of URT |
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where do bacteria colonize in the URT
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mucosal surface
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What is required for diphtheria toxin to be produced in situ?
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bacteria must carry beta-Tox bacteriophage
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diphtheria toxin causes ____ & _____
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localized destruction of epithelium
strong inflammatory response |
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Inflammatory response induced by diphtheria toxin
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outpouring of fibrinous exudate
influx of PMNs, which are killed by toxin, leading to further necrosis |
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diphtheria toxin causes pseudomembrane in throat, comprised of...
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dead host epithelial cells, blood, leukocytes, fibrin and bacteria
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effect of diphtheria-caused pseudomembrane
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spreads throughout bronchi, trachea
blocks respiration |
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3 targets of systemic toxemia caused by C. diphtheriae
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heart
kidneys nerves |
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3 effects of diphtheria toxin
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inflammatory response
pseudomembrane in throat systemic toxemia |
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prevention of diphtheria
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diphtheria toxoid vaccine
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