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Microbiology - Bacteria > Chapter 2: Bacterial virulence factors and toxins > Flashcards

Chapter 2: Bacterial virulence factors and toxins Flashcards

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Biology 101 flashcards
0
Q

How many pigment producing bacteria are there?

A

4

1) Actinomyces israelii
2) S. aureus
3) Pseudomonas aeruginosa
4) Serratia marcescens

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1
Q

Urease-positive bugs

A

“PUNCH KSS” (or CHuck Norris hates PUNKSS)

1) Proteus
2) Ureaplasma
3) Nocardia
4) Cryptococcus
5) H. pylori
6) Klebsiella
7) S. epidermidis
8) S. saprophyticus

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2
Q

What pigment does Actinomyces israelii produce?

A

“Israel has yellow sand”

Actinomyces israelii appear as yellow “sulfur” granules, which are composed of filaments of bacteria

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3
Q

Which microbe appears as yellow “sulfur” granules, composed of filaments of bacteria?

A

Actinomyces israelii

“Israel has yellow sand”

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4
Q

What pigment does S. aureus produce?

A

yellow

aereus means gold in Latin

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5
Q

Which microbe produces a yellow pigment?

A

Staph. auerus

aureus means gold in Latin

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6
Q

Pseudomonas aeruginosa produces what pigment?

A

blue-green pigment

AERUGala is green

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7
Q

What microbe produces a blue-green pigment?

A 
Pseudomonas aeruginosa
(AERUGala is green)
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8
Q

Serratia marcescens produces what color pigment?

A

red pigment

think red maraschino cherries for marcescens

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9
Q

What microbe produces a red pigment?

A

Serratia marcescens

think red maraschino cherries for marcescens

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10
Q

What is the function of the virulence factor, Protein A?

A

Protein A binds the Fc region of IgG and prevents opsonization and phagocytosis.

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11
Q

What virulence factor binds the Fc portion of IgG to prevent opsonization and phagocytosis?

A

Protein A

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12
Q

What microbe expresses IgA?

A

S. auerus

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13
Q

What is the function of the virulence factor IgA protease?

A

IgA protease cleaves IgA to allow certain bacteria to colonize respiratory mucosa (recall IgA antibody plays a critical role in mucosal immunity)

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14
Q

What virulence factor allows bacteria to evade mucosal immunity and colonize respiratory mucosa?

A

IgA protease

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15
Q

IgA protease is expressed by which bacteria? (3)

A

“SHiN”

1) S. pneumoniae
2) H. influenzae type B
3) Neisseria

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16
Q

What is the function of M protein?

A

M protein inhibits the action of complement to prevent phagocytosis

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17
Q

What virulence factor inhibits complement to prevent phagocytosis?

A

M protein

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18
Q

What microbe expresses M protein?

A

Group A streptococci (Strep. pyogenes)

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19
Q

Exotoxins are produced by what type of bacteria?

A

Exotoxins are released by most of the major gram-positives, and some species of gram-negative bacteria

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20
Q

Endotoxins are produced by which type of bacteria?

A

Most gram-negative bacteria (recall endotoxin, or Lipid A, is a component of LPS which is located on the outer cell membrane)

21
Q

Are exotoxins or endotoxins secreted from the cell?

A

Exotoxins are secreted

Endotoxins are released upon lysis of gram-negative bacteria

22
Q

What is the chemical composition of exotoxins versus endotoxins?

A

Exotoxins are composed of polypeptide.

Endotoxins are composed of lypopolysaccharide LPS

23
Q

Are exotoxins or endotoxins composed of polypeptide?

A

Exotoxins are composed of polypeptide

24
Q

Are exotoxins or endotoxins composed of lipopolysaccharide??

A

Endotoxins are composed of LPS

25
Q

What is the difference in location of genes of exotoxins versus endotoxins?

A

Exotoxin genes are located in plasmids or bacteriophages.

Endotoxin genes are located on the bacterial chromosome.

26
Q

Where are exotoxin genes located?

A

On plasmid or bacteriophage DNA

27
Q

Where are endotoxin genes located?

A

On bacterial chromosome

28
Q

Genes encoding which (exotoxin or endotoxin) are located on plasmids or bacteriophage DNA?

A

Exotoxin

29
Q

Genes encoding which (exotoxin or endotoxin) are located on bacterial chromosomes?

A

endotoxin

30
Q

What is the difference in toxicity of exotoxins versus endotoxins?

A

Exotoxins have high toxicity (fatal dose on the order of 1 ug).
Endotoxins have low toxicity (fatal dose on the order of hundreds of micrograms).

31
Q

What is the difference in antigenicity of exotoxins versus endotoxins?

A

Exotoxins induce high-titer antibodies called antitoxins.

Endotoxins are poorly antigenic.

32
Q

Are vaccines available or exotoxins or endotoxins?

A

Toxoids (endotoxins) used as vaccines.

No toxoids are formed for endotoxins, so no vaccine is available.

33
Q

What is the difference in heat stability of exotoxins versus endotoxins?

A

Exotoxins are destroyed rapidly at 60C (except for staphylococcal enterotoxin).
Endotoxins are stable at 100C for 1 hr.

34
Q

Which (exotoxins or endotoxins) are destroyed rapidly at 60C?

A

Exotoxins (except staphylococcal enterotoxins)

35
Q

Which (exotoxins or endotoxins) are stable at 100C for 1hr?

A

Endotoxins

36
Q

What are typical diseases associated with exotoxin? (3)

A

1) Tetanus
2) Botulism
3) Diphtheria

37
Q

Tetanus, botulism, and diphtheria are associated with (exotoxin or endotoxin)?

A

Exotoxin

38
Q

What diseases are typically caused by endotoxins? (2)

A

1) Meningococcemia

2) Sepsis by gram-negative rods

39
Q

Meningococcemia and sepsis are typical diseases caused by (exotoxin or endotoxin)?

A

Endotoxin

40
Q

Bacteremia - defn

A

bacteria in the bloodstream

41
Q

Sepsis - defn

A

Bacteremia that causes a systemic immune response to the infection:

  • high or low temperature
  • elevation of WBC
  • fast heart rate
  • fast breathing rate
42
Q

Septic shock - defn

A

Sepsis that results in dangerous drops in blood pressure (hypotension) and organ dysfunction (severe sepsis).

43
Q

mnemonic for characteristics of endotoxin?

A

ENDOTOXIN

1) Edema
2) Nitric oxide
3) DIC
4) Outer membrane
5) TNF-a
6) O-antigen
7) eXtremely heat stable
8) IL-1
9) Neutrophil chemotaxis

44
Q

Endotoxin (Lipid A) activates which 3 pathways?

A

1) macrophages
2) complement
3) tissue factor

45
Q

Endotoxin activates macrophages to release what 3 endogenous mediators of sepsis? What are the associated clinical signs?

A

1) TNF-a - fever and hypotension
2) IL-1 - fever
3) Nitric oxide - hypotension

46
Q

Endotoxin activates complement (which 2 components) which leads to what clinical signs? (2)

A

1) C3a - edema, hypotension

2) C5a - neutrophil chemotaxis

47
Q

Endotoxin activates the C3a component of complement which leads to what clinical signs?

A

Edema and hypotension

48
Q

Endotoxin activates the C5a component of complement which leads to what clinical sign?

A

Neutrophil chemotaxis

51
Q

Endotoxin activates tissue factor which can lead to what clinical sign?

A

coagulation cascade -> DIC

52
Q

What vital interventions should be performed immediately (<1 hr) of a diagnosis of sepsis?

A

The septic six: BUFALO

1) blood - draw blood cultures them prior to antibiotic administration
2) urine - insert urinary catheter and monitor hourly urine output
3) fluid - treat hypotension with IV fluids and drugs (dopamine and norepinephrine)
4) antibiotics - administer empiric broad spectrum antibiotics stat
5) lactate (and hemoglobin) - measure serum lactate and hemoglobin levels, associated with mortality
6) oxygen - maintain oxygenation, often with high flow O2 with intubation and mechanical ventilation

Microbiology - Bacteria (15 decks)

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