MOD2 Test 1

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  1. Streptococci that are Catalase Negative and Facultative Anaerobic
    • Streptococcus agalactiae (group B)
    • Group D- Enterococci and Non-enterococci
    • Streptococcus viridans
    • Streptococcus pneumoniae
    • Streptococcus pyogenes (group A) are microaerophilic
  2. Beta-hemolytic streptococci:
    • Streptococcus pyogenes (groupA)
    • Streptococcus agalactiae (groupB)
    • GroupD subtypes (are alpha, beta and gamma)

    Beta-hemolytic completely lyse the RBCs leaving a clear zone of hemolysis around the colony.
  3. Alpha-hemolytic Streptococci:
    • Streptococcus viridans
    • Streptococcus pneumoniae

    Alpha-hemolytic only partially lyse the RBCs leaving a greenish discoloration of the culture medium.
  4. Streptococcus pyogenes (groupA) virulence:
    • 1. M-protein: Adherence factor, Anti-phagocytic, Antigenic
    • 2. Lipoteichoic Acid- Adherence factor
    • 3. Streptokinase
    • 4. Hyaluronidase
    • 5. DNAase
    • 6. Anti-C5a peptidase
  5. Streptococcus agalactiae pathology:
    • 1. neonatal meningitis
    • 2. neonatal pneumonia
    • 3. neonatal sepsis
    • 4. sepsis in pregnant women (with secondary infection of fetus)
    • 5. increasing incidence of infections in elderly >65 years of age and patients with diabetes or neurological disease: causes sepsis and pneumonia
  6. Staphylococci (for our purposes) are:
    • Catalase positive
    • Facultative anaerobic

    • S. aureus- Coagulase positive
    • S. epidermidis, S. saprophyticus- Coagulase NEGATIVE
  7. Biofilm
    • Staphylococcus epidermidis
    • highly resistant to antibiotics
  8. Purulent meningitis with a rapid onset in young children and adults (not newborns)
    • Streptococcus pneumoniae
    • NOT S. agalactiae
  9. Gram-positive diplococci
    Streptococcus pneumoniae
  10. What is the major virulence factor of Streptococcus pneumoniae?
    • Capsule!
    • The halos visible around many of the cocci may be polysaccharide capusles of S. pneumoniae.
    • >80 types of capsules- differ in virulence, prevalence and drug resistance
    • Capsule interferes with phagocytosis by preventing complement C3b opsonization fo the bacterial cells.
  11. Characteristics of typical pneumonia:
    • sudden onset, chills, fever, dyspnea, productive cough with purulent sputum, rales
    • - Streptococcus pneumoniae (community acquired)
    • - others: Staphylococcus aureus (secondary, post viral)
  12. Characteristics of atypical pneumonia:
    gradual onset, nonproductive cough, headache, sore throat

    • -viral, uncommon in adults
    • - Mycoplasma, Chlamydia, Legionella
  13. Which bacteria ferment lactose?
    • Escherichia coli
    • Klebsiella pneumoniae
  14. What are the characteristics of Pseudomonas aeruginosa?
    • Hospital acquired- medical devices, healthcare workers
    • sweet, grape-like odor
    • produces pigments when cultured- pyocyanin and pyoverdin
Card Set:
MOD2 Test 1
2012-05-21 22:09:20

info from MRS charts
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