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Quiz 2 - Microbiology > Haemophilus and Bordetella > Flashcards

Haemophilus and Bordetella Flashcards

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Biology 101 flashcards
1
Q

Does Haemophilus have a capsule?

A

No

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2
Q

Which strain of hemophilus is the most virulent? What distinguishes between the different strains?

A

Type B strains are the most virulent. They have a capsule with ribose rather than hexose sugars

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3
Q

What is the quellung reaction used for? How does it work?

A

Used to visualize the capsule of bacteria. Works by adding antibody that binds to the capsule, causing it to swell

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4
Q

What are Haemophilus influenza B (Hib) reservoirs?

A

Nasopharynx of humans

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5
Q

What are the complications that can arise from invasive disease of HiB?

A 
Bacteremia
Meningitis
Epiglotitis
Cellulitis
Join infections
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6
Q

What toxin are we worried about with a HiB infection?

A

LPS endotoxin. This particular LPS is unique because it is decorated with host choline

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7
Q

When are infants most susceptible to Hi infection?

A

Between 6-12 months. Adaptive immunity develops at around 3-4 years.

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8
Q

Is there a vaccine to Hib? What is its structure?

A

Yes–very effective vaccine in place. It is a conjugate capsular Hib vaccine using synthetic carbohydrates. Must use a protein carrier to enhance immune response

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9
Q

What is the treatment with Hib infections?

A

3rd generation cephalosporins (cefotaxime, ceftrixone)

-beta lactamase inhibitor

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10
Q

What are the sites of infection for untypable Haemophilus?

A 
otitis media
sinusitis
tracheobronchitis
pneumonia
Can also cause conjunctivitis
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11
Q

What does it mean that a strain of haemophilus is nontypable?

A

Does not have a capsule

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12
Q

Adhesins are very important to H.i. colonization. Name the adhesins that are found in typeable and nontypeable Hi

A

Hap

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13
Q

Which adhesin is found in most non-typeable H.i.s?

A

HMW1/2

If missing HMW1/2, will most likely have Hia

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14
Q

Which adhesin is primarily found in typeable Hi?

A

Hsf

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15
Q

Is untypeable H.i. an extracellular or intracellular pathogen?

A

Both

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16
Q

What are the three routes of invasion for untypeable H.I.?

A

macropinocytosis, paracytosis, LPS-platelet activating factor

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17
Q

Can you develop long term immunity to untypeable H.i? Is there a vaccine?

A

Strain specific. For some strains, long term immunity never develops. There is also no vaccine

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18
Q

How do you treat NTHi? (Non-typeable H.i.)

A

amoxicillin. If resistant, add a beta-lactamase inhibitor

19
Q

What atmospheric growth conditions does Hi need (aerobe/anaerobe?)

A

facultative anaerobe

20
Q

What kind of agar plate do you need to grow H.i? This is diagnostic

A

chocolate agar with X factor (hemin) and V factor (NAD/NADP) which is released from RBCs

21
Q

Why does hemophilus influenzae usually accompany streptococcus?

A

Hi CANNOT lyse RBCs on its own. Needs a second pathogen to lyse cells to grant it access to necessary factors X and V

22
Q

How would you diagnose HiB?

A

culture blood and spinal fluid on chocolate agar and perform a gram stain

23
Q

Is Hi gram positive or negative? What is its morphology?

A

gram negative. Can alter its shape (pleiomorphic)

24
Q

Is bordetella pertussis gram positive or gram negative? What morphology does it have?

A

gram negative. Coccobacillus

25
Q

What atmospheric conditions does pertussis need to grow?

A

obligate aerobe!

26
Q

What are pertussis reservoirs?

A

Humans only

27
Q

What is the incubation period of bordetella pertusis?

A

7-10 days

28
Q

Describe the steps in the infectious process for bordetella:

A
  1. water droplets
  2. adherence to tracheal and nasopharyngeal epithelial cells
  3. Multiplication
  4. Toxin production
  5. Evasion of host defenses
  6. Transmission
29
Q

Can bordetella cause bacteremia?

A

No. However, the toxin can be distributed systemically

30
Q

What are the exotoxins produced by bordetella?

A

pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin

31
Q

What are the endotoxins produced by bordetella?

A

trachael cytotoxin

endotoxin (LPS)

32
Q

How does the pertussis toxin exert its effects?

A

Binds a Gi protein which inhibits adenylate cyclase inactivation. Constitutively active.What

  • Levels of cAMP rise
  • Causes lymphocytosis, increased insulin production, sensitization to histamine
33
Q

S1 subunit of pertussis toxin is the catalytic subunit. What is its name?

A

ADP-ribosylating toxin. It targets a G-protein, inhibits adenylate cyclase, and cAMP levels rise

34
Q

What do the S2-S6 subunits of the pertussis toxin do?

A

Aid in binding to toxin to target cells for S1 to do its magic.

35
Q

What does the adenylate cyclase toxin of bordetella do?

A

directly catalyzes production of cAMP from ATP in the host cell cytoplasm.

36
Q

What does dermonecrotic toxin (DNT) do?

A

Causes local necrosis and inflammation by acting on GTPase rho protein

37
Q

What does tracheal cytotoxin do?

A

Stops cilia from beating and kills tracheal epithelial cells

38
Q

What are the virulence determinant of bordetella associated with bacterial attachment?

A

Pili

  • filamentous hemagglutinin binds galactose moieties
  • pertactin surface molecule
  • tracheal colonization factor
39
Q

Which one of the toxins secreted by bordetella is responsible for the whooping cough?

A

Pertussis toxin

40
Q

What were issues with the early bordetella vaccine?

A

Contamination with LPS. Hard to issolate only the other virulence factors

41
Q

What are the components of the new pertussis vaccine?

A

Acellular petussis component vaccine

  • Pertussis toxoid prevents symptoms. The other components prevent infection.
  • Fha
  • pertactin
  • Fimbrae
42
Q

How would you diagnose whooping cough?

A

PCR detection for Bordetella-specific insertion sequences (IS)

  • Culture on Bordet-gengou agar with glycerol, starch, and blood (uncommon)
  • Lymphocytosis
  • Classic cough
43
Q

How do you treat B. pertussis?

A

Erythromycin.

B. Pertussis is RESISTANT to ampicillin+penicillin

44
Q

What are the bordetella subspecies?

A 
B parapertussis (lacks some toxins. Similar symptoms to whooping cough)
Bbronchispetica (Rare, only in immunocomprised. Can cause pneumonia)

Quiz 2 - Microbiology (6 decks)

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