Test 2 Micro: (Ppts 13,14,17)

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BrookeNH10
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180098
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Test 2 Micro: (Ppts 13,14,17)
Updated:
2012-10-26 16:19:21
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Staph
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Staph
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  1. Staph:
    aerobe/non-aerobe status?
    Which enzyme, which can also be used as a virulence factor, is produced by all Staph?
    • Facultative aerobe (ferment)
    • Catalase
  2. What is the role of PIA (Polysaccharide Intercellular Adhesin) in Staph?
    Produces a sticky biofilm.
  3. Which staph is urease positive?
    Saprophyticus
  4. Which Staph is Novobiocin sensitive?
    Epidermidis
  5. Which Staph is mannitol positive?
    Staph aureus
  6. Staph. aureus has what type of hemolysis and what type of pigment on blood agar?
    Beta hemolysis (now most are non-hemolytic), yellow pigment
  7. Staph. epidermidis has what type of hemolysis and what color pigment on blood agar?
    No hemolysis, white colony
  8. Frequent contaminant of blood samples?
    S. epidermidis
  9. Where is Staph. saprophyticus found?  How?
    Vaginal adherence by hemagglutinin
  10. S. saprophyticus (cause of honeymoon cystitis) adheres to urinary tract and releases?  This causes
    Urease --> Kidney stones
  11. Sequence each of 7 genes on the chromosome.  Every sequence of a gene has a # and the numbers for the 7 genes define the strain; a new sequence is given the next highest # for that gene.
    Multi-locus sequence typing (identifies strains of S. aureus)
  12. Name 2 host defenses against S. aureus.
    • Phospholipase A2
    • Phagocytosis

    (Lysozyme does NOT kill staph!)
  13. S. aureus:  Multiple skin lesions connected by sinuses in the connective tissue
    Carbuncle
  14. S. aureus:  Crusting vesicle formation of the skin
    Impetigo
  15. S. aureus:  Infection of the nail bed.
    Paronychia
  16. S. aureus:  Spreading connective tissue infection
    Cellulitis
  17. S. aureus: eyelid infection
    Blepharitis
  18. S. aurues:  Corneal infection
    Keratitis
  19. S. aureus:  Inner eye infection
    Endophthalmitis
  20. What is the most important complication of S. aureus pyoderma?
    • Spread of infection.
    • Sinuses--> Brain
    • Skin --> Blood --> Heart, bone, brain
  21. Which Staph causes osteomyelitis?
    S. aureus
  22. Name 3 components of S. aureus surface.
    Capusle, PIA, techoic acids (carb polymers)
  23. Sequence that directs the secretion and cell wall binding of cell wall proteins of S. aureus that.
    MSCRAMM (microbial surface components recognizing adhesive matrix molecules)
  24. Enzyme that links MSCRAMM to the wall near their C-terminus
    Sortase
  25. Cell Wall Associated Adherence Proteins:
    Bind to blood clots and objects exposed to blood
    Fibrinogen Binding Proteins
  26. Cell Wall Associated Adherence Proteins:
    Binds to bone/joints
    Collagen Binding Protein
  27. Cell Wall Associated Adherence Proteins:
    Binds to fibronectin (in wounds) and to many molecules and surfaces- very important for binding to tissues.
    Fibronectin Binding Proteins
  28. Name the 3 Cell Wall associated adherence proteins for Staph.
    • Fibrinogen BP
    • Collagen BP
    • Fibronectin BP
  29. Protein A
    Cell wall Protein A binds:
    Cell wall Protein A binds:  TNFa Receptor
    • Major virulence factor of Staph. aureus
    • Cell wall Protein A --> Fc portion of IgG
    • Secreted Protein A --> TNFa Recpetor (causes inflammation)
  30. Explain Staphylococcus agr
    Inducer (octopeptide) binds to receptor --> shuts down cell wall synthesis and upregulates proteins for excretion
  31. Other than agr, what is another important regulatory system of Staphylococcus?
    X,Y,Z --> Sar (upregulates amnt of toxin produced)
  32. agr mutant:
    High or low mutation rate?
    Can it make exotoxins?
    Can it be phagocytized?
    What kind of mutation will allow alpha-toxin production? 
    • High mutation rate
    • Can't make exotoxins
    • Can be phagocytized, but may survive in certain cells
    • Back mutation will allow alpha-toxin production
  33. S. aureus exoprotein that kills PMN, often found in CA-MRSA.
    Panton Valentine Leukocidin
  34. Alpha-toxin damages?
    Tissue
  35. What does alpha-toxin bind on lipid rafts?
    Caveolin
  36. What toxin of S. aureus causes pneumonia?
    Alpha-toxin (causes epithelial cells of the air sac and capillary to slough off)  Blood goes into airsac --> Blood pneumonia
  37. Recently recognized small secreted peptides that can kill PMNs (may also help bacteria spread from biofilm)
    Modulins
  38. Bind complement component C5a receptors to prevent chemotaxis.
    CHIPS (Chemotaxis Inhibiting ProteinS)
  39. CHIPS inactivate what gene when it integrates into the S. aureus chromsome?
    B-hemolysin
  40. What do the Super-Antigne-Like Proteins of S. aureus do?
    Block complement/opsonins that lead to phagocytosis and bacterial killing
  41. Name S. aureus' Enterotoxins
    Superantigens, neurotoxins, damage gut
  42. TSST is a
    superantigen
  43. Exfoliative toxin is a?
    Protease
  44. Product of lysogenic conversion and a superantigen
    Enterotoxin
  45. #1 cause of food-borne illness in the US.
    S. aureus
  46. Tampon toxic shock due to?
    S. aureus
  47. TSST is located on a
    pathogenicity island.
  48. What two skin syndromes are due to S. aureus?
    • Scalded Skin Syndrome
    • Bulbous Impetigo
  49. What toxin causes Scalded Skin Syndrome?
    Exfoliative toxin
  50. Mediate transfer of large chromosomal regions.
    ICE (Integrated Conjugal Elements)
  51. Treat MSSA (Methicillin Sensistive Staph. a) with:
    • Anti-Staph Penicillin:  If Staph only
    • Cephalosporins
    • Vancomycin
  52. SCCmec codes for what gene?
    What is the product of this gene?
    • mecA gene
    • PBP2 (transpeptidase which builds cell walls despite B-lactam)
  53. Drug that can inhibit the mecA-coded transpeptidase (PBP2a) of MRSA
    Ceftaroline
  54. SCCmec Structure
    Plasmid DNA-mecA Complex- ccr- Plasmid DNA
  55. ccr of SCCmec (dynamic) Cassette codes for:
    Recombinase (allows cassette to acquire more DNA)
  56. SCCmec's have the ability to
    acquire more DNA
  57. What mec cassette types are in hosptial MRSA
    Types I to III
  58. Describe how staph is vancomycin resistant (VIRSA)
    Thick cell wall (retains D-ala-D-ala) binds vancomycin near surfae, but the wall is too thick for vancomycin to penetrate.
  59. Alpha-Toxin binds to liid and a protein called
    Adam 10
  60. Adam 10 cleaves
    E-cadherin which holds epithelial and endotheial cells in place -> cleave this, cells can slough off
  61. Quinupristin/Dalfopristin (Synercid):
    Streptogamin antibiotic that binds to 50S subunit of bacterial ribosomes and leads to inhibiton of bacterial protein synthesis.
  62. Linezolid (Zyvox)
    Oxazolidinone antibiotic, binds to 50S subunit of bacterial ribosomes and leads to inhibition of bacterial protein synthesis.

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