Jeef First Aid Micro Part 1-3

Front 1

61. What reaction will be positive if encapsulated bacteria is present?

Back 1

a. Quellung reaction. If an encapsulated bug is present, the capsule swells when specific anticapsular antisera are added.
b. Quellung = capsular “swelling”

Front 2

62. 6 Encapsulated bacteria? Some Killers Have Nice Shiny Bodies.

Back 2

1. Strep pneumoniae.
2. Klebsiella pneumoniae
3. Haemophilus influenzae type B
4. Neisseria meningitidis
5. Salmonella
6. group B strep.
b. Their capsules serve as antiphagocytic virulence factors.

Front 3

63. How do vaccines work?

Back 3

a. For vaccines containing a polysaccharide capsule antigen, a protein is conjugated to the polysaccharide antigen to promote T-cell activation and subsequent class switching.
b. A polysaccharide antigen alone would not be recognized and presented by T cells; therefore, only IgM antibodies would be produced.

Front 4

64. Urease-positive bugs?

Back 4

1. Proteus
2. Klebsiella
3. H. Pylori
4. Ureaplasma.

Front 5

65. Pigment produced by Actinomyces israelii?

Back 5

a. Yellow “sulfur” granules, which are composed of a mass of filaments and formed in pus.

Front 6

66. Pigment produced by S. aureus?

Back 6

a. Yellow pigment.

Front 7

67. Pigment produced by Pseudomonas aeruginosa?

Back 7

a. Blue-green pigment. “AERUGula is green.

Front 8

68. Pigment produced by Serratia marcescens?

Back 8

a. Red pigment.
b. Think red maraschino cherries.

Front 9

69. Protein A?

Back 9

a. Binds Fc region of Ig.
b. Prevents opsonization and phago.
c. Used by S. aureus.

Front 10

70. What bugs secrete IgA protease (cleaves IgA)?

Back 10

1. S. pneumoniae
2. H. influenzae type B
3. Neisseria
b. Helps them colonize respiratory mucosa.

Front 11

71. What is the function of the M protein and which bug uses it?

Back 11

a. Helps prevent phagocytosis in group A streptococcus. (pyogenes).

Front 12

72. Exotoxin Source, chemical nature, and location in genes?

Back 12

a. Secreted by some G+ and G- bacteria.
b. Polypeptide
c. Located in Plasmid or bacteriophage.

Front 13

73. Endotoxin Source, chemical nature, and location in genes?

Back 13

a. Outer cell membrane of most G- bacteria.
b. Composed of lipopolysaccharide (released when lysed)
c. Located in Bacterial chromosome.

Front 14

74. Toxicity of exotoxin vs. endotoxin?

Back 14

a. Exotoxin- High (fatal dose on order of 1 μg). Induced high-titre antibodies called antitoxins.
b. Endotoxin- Low (fatal dose on order of hundreds of micrograms). Poorly antigenic.

Front 15

75. Vaccines against exotoxin?

Back 15

a. Toxoids used as vaccine.

Front 16

76. Vaccine against endotoxin?

Back 16

a. No vaccines available.

Front 17

77. Heat stability of exotoxin vs. endotoxin?

Back 17

a. Exotoxin- destroyed rapidly at 60C (except staph enterotoxin)
b. Endotoxin- head stable at 100C for 1 hr.

Front 18

78. Endotoxin typical diseases?

Back 18

a. Meningococcemia, sepsis by G- rods.

Front 19

79. Superantigens?

Back 19

a. Bind directly to MHC II and TCR simultaneously, activating large numbers of T cells to stimulate release of IFN-γ and IL-2.

Front 20

80. Bugs w/ Superantigen exotoxins?

Back 20

a. S. aureus
b. S. pyogenes.

Front 21

81. S. aureus superantigen?

Back 21

a. TSST-1 superantigen causes toxic shock syndrome (fever, rash, shock).
b. Other S. aureus toxins include:
i. Enterotoxins-that cause food poisoning.
ii. Exfoliatin- Causes staph scalded skin syndrome

Front 22

82. S. pyogenes superantigen?

Back 22

a. Scarlet fever-erythrogenic toxin causes toxin shock-like syndrome.

Front 23

83. ADP ribosylating A-B toxins?

Back 23

a. ADP ribosylating A-B toxins interfere w/host cell function. B(binding) components bind to a receptor on host cell surface, enabling endocytosis.
b. A (active) component then attaches and ADP-ribosyl to a host cell protein (ADP ribosylation), altering protein function.

Front 24

84. Bugs which use ADP ribosylating A-B toxins (4)?

Back 24

1. Corynebacterium diphtheriae
2. Vibrio cholerae
3. E. coli
4. Bordetella pertussis

Front 25

85. Corynebacterium diphtheriae ADP ribosylating A-B toxin?

Back 25

a. Inactivates elongation factor (EF-2) (similar to pseudomonas exotoxin A)
b. Causes pharyngitis and “pseudomembrane in throat”.

Front 26

86. Vibrio cholerae ADP ribosylating A-B toxins?

Back 26

a. ADP ribosylation of G protein stimulates adenylyl cyclase
b. Pumps Cl- into gut and decreases Na absorption.
c. H20 moves into gut lumen; causes rice-water diarrhoea.

Front 27

87. E. coli ADP ribosylating A-B toxins? (“Labile like the Air, stable like the Ground.

Back 27

a. Heat-labile toxin stimulates Adenylate cyclase.
b. Heat-stable toxin stimulates Guanylate cyclase.
c. Both cause watery diarrhoea.

Front 28

88. Bordetella pertussis ADP ribosylating A-B toxins?

Back 28

a. Increases cAMP by inhibiting Gα1
b. Causes whooping cough
c. Inhibits chemokine receptors, causing lymphocytosis.

Front 29

89. Clostridium perfringens exotoxin?

Back 29

a. α toxin, a Lecithinase that acts as phospholipase to cleave cell membranes and causes gas gangrene.
b. Get double zone of hemolysis on blood agar.

Front 30

90. C. tetani exotoxin?

Back 30

a. Blocks the release of inhibitory neurotransmitters GABA and glycine; causes “lockjaw”.