Bordetella

Question 1

General characteristics (2)

Answer 1

Gram-negative

Coccobacilli

(Non-motile, Non-sporing)

Question 2

Cultivation

Answer 2

Selective Media

Bordet-Gengou medium

Question 3

Bordetella Species (4)

Answer 3

1- B.pertussis

2- B.parapertussis

3- B.holmessi

4- B.bronchiseptica

Question 4

What type of infection do these species cause?

Answer 4

Respiratory infection

Question 5

What is special about B.bronchiseptica?

Answer 5

Causes respiratory infection in animals and humans pick up infection after animal exposure

Question 6

What does B.pertussis cause?

Answer 6

Pertussis (cough)

Question 7

What are the 3 phases of Pertussis?

Answer 7

1- Catarrhal phase (simple cough)

2- Paroxysmal phase (severe cough)

3- Convalescent phase

Question 8

What is special about Paroxysmal phase? (3)

Answer 8

Paroxysmal cough with no pause of air intake and occurrence of CYANOSIS

When a final cough clears secretions from the respiratory tract, air is sucked through the narrowed glottis —> produced high-pitched whoop = WHOOPING COUGH

Cough may be followed by VOMITTING (POSTTUSSIVE EMESIS)

Question 9

Is it more severe in young infants or adolescents/adults?

Answer 9

Young infants bc develop more severe complications

Adolescents/adults = prolonged cough

MICROASPIRATION = Leaking of secretion into respiratory tract

Question 10

B.pertussis Virulence Factors (5)

Answer 10

1- PERTACTIN and FILAMENTOUS HEMAGGLUTININ —> Promote ATTACHMENT of bacteria to CILIATED epithelial cells

2- TRACHEAL Cytotoxin —> INHIBITS CILIA movement and REGENERATION of DAMAGED cells

3- PERTUSSIS Toxin —> Causes LYMPHOCYTOSIS, HISTAMINE SENSITIZATION, activation of INSULIN-PRODUCING cells causing HYPOGLYCEMIA

4- ADENYLATE CYCLASE Toxin —> DECREASED CHEMOTAXIS and SENSITIZATION of bacteria

5- DERMONECROTIC Toxin —> VASOCONSTRICTION and ISCHEMIC NECROSIS

Question 11

Transmission

Answer 11

Source = Nasopharynx

Transmission = Droplets

Question 12

Lab Diagnosis (2)

Answer 12

1- Direct Fluorescent Antibody (DFA)

2- PCR on Nasopharyngeal swab targeting Insertion Sequence elements (mobile DNA elements)

Question 13

Vaccine

Answer 13

DPT Vaccine (Developed countries)

1- (wP) —> Pertussis component contains killed whole cells (gives side-effects in some children)

2- (aP) —> Acellular pertussis contains pertussis toxoid, pertactin, filamentous haemagglutinin, and fimbriae types 2 and 3 instead of whole cells