Bordetella

Question 1

Bordetella Morphology/staining:

Answer 1

Gram-negative
Aerobic coccobacilli
Tiny

Question 2

Bordetella is found in the ______ tract.

Answer 2

Found in the respiratory tract

Question 3

Bordatella culture:

Answer 3

Strict aerobe
Non-motile
Non-spore forming
Catalase positive

Question 4

Why is Bordatella difficult to grow?

Answer 4

Sensitive to drying

Susceptible to toxic metabolites that are produced by the bacteria as they grow on the plate

Question 5

Bordatella media:

Answer 5

Requires agar supplemented with charcoal, starch, blood, or albumin that absorbs toxic substances and metabolites

Question 6

B. pertussis virulence factors:

Answer 6

No polysaccharide capsule

Pertactin and filamentous hemagglutinin (Fha)

Toxins are major virulence factor:
Pertussis toxin (PT)
Adenylate cyclase toxin

Question 7

Bordetella mechanism of infection:

Answer 7

Affects distal respiratory tract epithelium (trachea and bronchial tree) where ciliary movement is fairly important

Filamentous hemagglutinin attached to the cilia on the surface of the respiratory tract cells

Toxin production helps mediate ciliary stasis. The loss of ciliary movement helps facilitate persistence of the bacterial infection in the bronchial tree

Question 8

Describe function of the pertussis toxin subunits:

Answer 8

A subunit catalyzes ADP ribosylation of a cellular regulatory protein (G- protein) which prevents inactivation of adenylate cyclase

B subunit binds to receptors on ciliated respiratory cells and phagocytic cells

Question 9

How is pertussis toxin released:

Answer 9

Released by the organism at the surface of the cell, gets endocytosed, and blocks a protein that inhibits production of cAMP leading to increased cAMP levels.

Question 10

Biologic effects of pertussis toxin:

Answer 10

Increased respiratory secretions
mucus production
lymphocytosis

Question 11

Describe the function and mechanism of adenylate cyclase toxin:

Answer 11

Causes increased cAMP levels in host cells

Interferes with chemotaxis and superoxide production of leukocytes

Results in increased respiratory secretions and swelling in the respiratory epithelium

Question 12

Transmission of Bordetella pertussis

Answer 12

Spread by respiratory droplets and highly infectious

Only human pathogen; no other reservoir

Question 13

Typical demographic of B. pertussis:

Answer 13

Most common and severe in infants from birth to 2 years

Question 14

Mechanism of transmission of B. pertussis from adults to infants:

Answer 14

Adults can have an asymptomatic infection (subclinical or milder clinical disease) making them a major reservoir of spread to infants who have more severe disease

Question 15

4 stages of pertussis infection:

Answer 15

Incubation
Catarrhal
Paroxysmal Cough
Convalescent

Question 16

Length and symptoms of pertussis incubation stage:

Answer 16

Incubation - 7-10 days

No symptoms

Question 17

Length and symptoms of pertussis Catarrhal stage:

Answer 17

Lasts 1 - 2 weeks

Characterized by rhinorrhea, malaise, fever, sneezing, anorexia

Question 18

Length and symptoms of pertussis Paroxysmal cough stage:

Answer 18

Cough up to 50 times a day for 2-4 weeks

Inspiratory whoop, vomiting, mucoid secretions, marked lymphocytosis (common)

Question 19

Length and symptoms of pertussis Convalescent stage:

Answer 19

Lasts 3-4 weeks

Cough gradually fades, development of secondary complications

Question 20

In which stage is pertussis usually diagnosed?

Answer 20

Paroxysmal Cough Stage

Question 21

What are the secondary complications of pertussis and when do they occur?

Answer 21

Pneumonia (S. pneumoniae), atelectasis, convulsions, hemorrhage following Convalescent stage

Question 22

Most effective treatment of B. pertussis and when is it most effective?

Answer 22

Macrolide treatment; only effective in catarrhal stage, not the paroxysmal stage

Question 23

Modes of diagnosis for B. pertussis:

Answer 23

Culture nasopharyngeal sample on charcoal Regan-Lowe media

Nucleic acid (PCR) testing of 
Nasopharyngeal specimen

Only beneficial in the early catarrhal stage

Question 24

Nucleic acid (PCR) testing of a
nasopharyngeal specimen is only beneficial in the early \_\_\_\_\_\_\_ stage of pertussis for diagnosis.

Answer 24

Nucleic acid (PCR) testing of a
nasopharyngeal specimen is only beneficial in the early catarrhal stage of pertussis for diagnosis.