FASTIDIOUS GRAM NEGATIVE RODS. PART 4

Question 1

Explain the appearance of bordetella pertussis

Answer 1

Is a small, aerobic, encapsulated gram negative rod

Question 2

What disease is caused by bordetella pertussis

Answer 2

Causes wooping cough

Question 3

how is bordetella pertusis transmitted

Answer 3

Transmitted from person to person via respiratory droplets

Question 4

Explain the complications of bordetella pertussis

Answer 4

1. Lung damage with emphysema,
   2.Secondary infection leading to 3.bronchopneumonia,
2. Bronchiectasis,
3. Convulsions and
4. Occasionally brain damage

Question 5

How does B. pertussis invade the human host?

Answer 5

B. pertussis invades the human host through the inhalation of respiratory droplets.

Question 6

What types of toxins does B. pertussis produce, and what is their role?

Answer 6

B. pertussis produces an endotoxin, an exotoxin, and hemagglutinins. These are surface antigens that help the bacteria attach to the cilia of epithelial cells in the upper respiratory tract. The toxins destroy the ciliated epithelial cells.

Question 7

What happens to the epithelial cells after they are destroyed by the toxins?

Answer 7

After the toxins destroy the ciliated epithelial cells, those cells are sloughed off, leaving a surface of non-ciliated cells. This change allows mucus to accumulate within the respiratory airway.

Question 8

What changes occur in the blood count during an infection with B. pertussis?

Answer 8

During an infection with B. pertussis, there is a marked leukocytosis with an absolute lymphocytosis, indicating an increase in white blood cells, particularly lymphocytes.

Question 9

what is the gram negative result for B. pertussis

Answer 9

1. B. pertussis is a small, non-motile, capsulated Gram negative coccobacillus.
2. It may occur singly or in chains, and may show bipolar staining

Question 10

where can B. pertussis be isolated from

Answer 10

B. Pertussis can be isolated from nasopharyngeal swabs taken during the paroxysmal stage

Question 11

what are the culture requirements for Bordatella pertussis

Answer 11

A selective and enrichment medium such as charcoal cephalexin blood agar
recommended

Question 12

What are the culture results for B. pertussis

Answer 12

When incubated for 2–6 days at 35–37 ºC in a moist aerobic atmosphere, B. pertussis
produces small pearly-grey, shiny (mercury-like), usually mucoid colonies.

Question 13

What is the treatment for Bordatella pertussis

Answer 13

1. Azithromycin, erythromycin or clarithromycin preferred.
2. Supportive care (e.g., oxygen therapy and suction of mucus) during the
   paroxysmal stage is important, especially in infants.

Question 14

Prevention of bordetella pertussis

Answer 14

1. Immunization (to children 2 months of age)