Haemophilus and Bordetella

Question 1

Does Haemophilus have a capsule?

Answer 1

No

Question 2

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

Answer 2

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

Question 3

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

Answer 3

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

Question 4

What are Haemophilus influenza B (Hib) reservoirs?

Answer 4

Nasopharynx of humans

Question 5

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

Answer 5

Bacteremia
Meningitis
Epiglotitis
Cellulitis
Join infections

Question 6

What toxin are we worried about with a HiB infection?

Answer 6

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

Question 7

When are infants most susceptible to Hi infection?

Answer 7

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

Question 8

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

Answer 8

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

Question 9

What is the treatment with Hib infections?

Answer 9

3rd generation cephalosporins (cefotaxime, ceftrixone)

-beta lactamase inhibitor

Question 10

What are the sites of infection for untypable Haemophilus?

Answer 10

otitis media
sinusitis
tracheobronchitis
pneumonia
Can also cause conjunctivitis

Question 11

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

Answer 11

Does not have a capsule

Question 12

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

Answer 12

Hap

Question 13

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

Answer 13

HMW1/2

If missing HMW1/2, will most likely have Hia

Question 14

Which adhesin is primarily found in typeable Hi?

Answer 14

Hsf

Question 15

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

Answer 15

Both

Question 16

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

Answer 16

macropinocytosis, paracytosis, LPS-platelet activating factor

Question 17

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

Answer 17

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

Question 18

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

Answer 18

amoxicillin. If resistant, add a beta-lactamase inhibitor

Question 19

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

Answer 19

facultative anaerobe

Question 20

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

Answer 20

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

Question 21

Why does hemophilus influenzae usually accompany streptococcus?

Answer 21

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

Question 22

How would you diagnose HiB?

Answer 22

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

Question 23

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

Answer 23

gram negative. Can alter its shape (pleiomorphic)

Question 24

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

Answer 24

gram negative. Coccobacillus

Question 25

What atmospheric conditions does pertussis need to grow?

Answer 25

obligate aerobe!

Question 26

What are pertussis reservoirs?

Answer 26

Humans only

Question 27

What is the incubation period of bordetella pertusis?

Answer 27

7-10 days

Question 28

Describe the steps in the infectious process for bordetella:

Answer 28

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

Question 29

Can bordetella cause bacteremia?

Answer 29

No. However, the toxin can be distributed systemically

Question 30

What are the exotoxins produced by bordetella?

Answer 30

pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin

Question 31

What are the endotoxins produced by bordetella?

Answer 31

trachael cytotoxin | endotoxin (LPS)

Question 32

How does the pertussis toxin exert its effects?

Answer 32

Binds a Gi protein which inhibits adenylate cyclase inactivation. Constitutively active.What - Levels of cAMP rise - Causes lymphocytosis, increased insulin production, sensitization to histamine

Question 33

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

Answer 33

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

Question 34

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

Answer 34

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

Question 35

What does the adenylate cyclase toxin of bordetella do?

Answer 35

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

Question 36

What does dermonecrotic toxin (DNT) do?

Answer 36

Causes local necrosis and inflammation by acting on GTPase rho protein

Question 37

What does tracheal cytotoxin do?

Answer 37

Stops cilia from beating and kills tracheal epithelial cells

Question 38

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

Answer 38

Pili - filamentous hemagglutinin binds galactose moieties - pertactin surface molecule - tracheal colonization factor

Question 39

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

Answer 39

Pertussis toxin

Question 40

What were issues with the early bordetella vaccine?

Answer 40

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

Question 41

What are the components of the new pertussis vaccine?

Answer 41

Acellular petussis component vaccine - Pertussis toxoid prevents symptoms. The other components prevent infection. - Fha - pertactin - Fimbrae

Question 42

How would you diagnose whooping cough?

Answer 42

PCR detection for Bordetella-specific insertion sequences (IS) - Culture on Bordet-gengou agar with glycerol, starch, and blood (uncommon) - Lymphocytosis - Classic cough

Question 43

How do you treat B. pertussis?

Answer 43

Erythromycin. | B. Pertussis is RESISTANT to ampicillin+penicillin

Question 44

What are the bordetella subspecies?

Answer 44

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