MMI 301: Listeriosis/Diphtheria

Home > Flashcards > Print Preview

The flashcards below were created by user Anonymous on FreezingBlue Flashcards. What would you like to do?

  1. Listeria's Namesake
    Joseph Lister
  2. Monocyte
    Mononuclear leukocytes that infiltrate during infection
  3. Listeria Morphology
    • -Small gram-positive rod
    • -Facultative anaerobic
    • -Motile at 25 degree and below
    • -Beta-Hemolysis/Catalase (+)
    • -Grow at 4 degrees and in high salt
  4. Listerial Diseases in Pregnant Women:
    Minor febrile gastroenteritis, bacteremia, spontaneous abortion
  5. Listerial Diseases in Neonates/fetus:
    meningitis, death
  6. Listerial diseases in the Immunosuppressed
    meningitis, sepsis, death
  7. Listerial diseases in healthy adults
    rarely: bacteremia, sepsis, CNS infection, minor febrile gastroenteritis
  8. Diagnosing Listeria
    • Positive Gram Stain
    • Cold enrichment
    • Motility
    • beta-Hemolysis
  9. Sources of Listerial Infection
    • Zoonotic fecal-oral foodborne infection
    • Associated with unpasteurized cheeses, ready-to-eat meats/foods, produce
    • Can replicate in fridge, survive in freezer
  10. Listeria Virulence Factors
    • Listeriolysin O (LLO)
    • Actin polymerization factor ActA
  11. Listeria monocytogenes Infection/Pathogenesis
    • Crosses intestinal barrier to cause invasive disseminated disease
    • Replicates inside of epithelial cells, hepatocytes, bactericidal macrophages
    • Not effected by antibody/complement responses because intracellular
  12. Listeriolysin O
    • Essential for Virulence
    • Binds to cholesterol containing membranes
    • Attaches pores through which cytoplasm can escape
    • Lyses phagosome
    • Most active at 5.5 pH
    •    -This means it is best at lysing phagosomes, not host cell membranes, keeping their environment intact
  13. ActA
    • Essential Virulence Factor for bacteria
    • Facilitates cell to cell spread
    • Uses hosts cytoskeleton
    • Similar to other intracellulars: Shigella, Ricketsia, Burkholderia
    • Used to understand host cells
  14. Listeria treatment
    • Ampicillin/Amoxacillin and Gentamycin
    • 20-30% fatality rate with treatment
  15. Listeria Outbreaks
    • 2011 (Jensen Farms Cantalope): 147 infected, 33 dead, 1 miscarriage, 60 day incubation time
    • 2012 (Frescolina Marte Brand Ricotta Salata Cheese): 20 infected, 4 dead.
  16. Listeria monocytogenes Immunity
    • Requires cellular mediated, humoral doesn't work.
    • Infection leads to long term protective immunity
    • No use for vaccine, chemotherapeutic is in making
  17. L. monocytogenes Immunotherapy
    • Immunotherapy: Utilizes body's natural immune system to fight infection
    • Use attenuated strains (deltaActA/inlB or deltaprfA+hly) to safely immunize
    • Engineer L. mono to express tumor antigens (HPV-E7/mesothelin)
    • Stimulate antigen specific T-cell response
  18. Corynebacterium diphtheriae Morphology
    • koryne-club
    • Bacterion- little rod
    • Small, Gram-positive bacilli (often irregular shape)
    • Non-motile
    • Facultative aerobe
    • Catalase +
    • Urease -
  19. Symptoms of Diphtheria
    • Respiratory:
    • Mostly in children
    • Fever/Sore throat
    • Pseudomembrane/pharynx
    •   -composed of fibrin, leukocytes, necrotic epithelial cells, and diphtheria
    • Cutaneous:
    • Minor lesions to non-healing ulcers
  20. Diphtheria Diagnosis
    • Gram + rods in throat swab
    • Black colonies on potassium tellurite agar
    • methylene blue stain in Loeffler's coagulated blood agar
  21. Diphtheria Toxin (DT)
    • Encoded by temperate beta-phage
    • Expression induced upon iron starvation
    • Is AB toxin
    •    -three subunits B/T/A: Binding, Translocation, Active
    •    -Transloction needs phagosome acidification
    • Receptor discovered through cDNA library cloning
    •     -HB-EGF heparin-binding epidermal growth factor
    • DT enters cells and ADP-ribosylates EF-2
    •     -EF-2 required for protein synthesis
    •     -Uniquely modified histidine in EF-2 called diphthamide is target of DT
    •     -Inhibition causes cell death
  22. Diphtheria History
    • Killed 80% of children under ten in early colonies
    • In 1920s, 200,000 cases/13-15,000 deaths
    • Worldwide Today: 30,000 cases/3,000 dead
  23. Diphtheria Treatment
    • Antitoxin: Neutralizes toxin (antibodies)
    • Penicillin/Erythromycin: eliminate colonizing bacteria, prevent additional secretion
    • DPT Vaccine: ensure long term protective immunity, infection does not always cause immunity
  24. Diphtheria Vaccine History
    • 1890-antitoxin treatment by Emil von Behring (horse/guinea pig)(first nobel prize in med.)
    • 1894-Early use of antitoxin (horse) in US
    • 1914: William Park shows combo antitoxin/toxin can confer immunity
    • 1923: Gaston Ramon/Alexander Glenny develop DT toxoid using heat/formalin.
    • 1964: Adjuvant added to the DTP vaccine
    • 2003: last documented case of Diphtheria in US
  25. Current Diphtheria Vaccines in US
    • DTap: Diphtheria, Tetanus, acellular Pertussis
    • DT: Diphtheria, Tetanus
    • Tdap: Tetanus, diptheria, acellular pertussis
    • Td: Tentanus, diphtheria
  26. Important Factoids
    • Listeria monocytogenes is an important foodborne pathogen that primarily affects pregnant women and still causes outbreaks in
    • the US
    • L. monocytogenes requires Listeriolysin O and ActA to cause disease

    L. monocytogenes is being developed as an immunotherapeutic tool

    • Corynebacterium diphtheriae causes
    • the disease Diphtheria through the activation of cell death by circulating Diphtheria toxin

    Diphtheria Toxin works by inhibiting protein synthesis in host cells through the ADP ribosylation of EF-2

    Inactivated Diphtheria Toxin is a highly effective vaccine that has eradicated Diphtheria in the US since 2003

Card Set Information

MMI 301: Listeriosis/Diphtheria
2013-10-31 19:26:15
MMI 301

MMI 301
Show Answers:

What would you like to do?

Home > Flashcards > Print Preview