Bordetella pertussis

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Bordetella species of
clinical importance
B. pertussis
B. parapertussis
B. bronchosepticus
A 2-year-old male is presented to you with a 10-day
history of persistent cough. The long cough spells are
followed by a deep breath. The cough often leads to
choking, vomiting, gasping and cyanosis. His pulse rate
is 190 (n: 100-160) and respiratory rate is 72 (n: 10-20).
Chest x-ray is normal. WBC counts are16,000/cm2 with
70% lymphocytes.
1.
2.
3.
4.
What is the organism and what are its physiologic
characteristics?
What are the pathogenic factors of this organism?
Why is there a preponderance of lymphocytes?
What is the epidemiology of and prophylaxis for the
disease?
Bordetella pertussis
Causative agent of whooping cough
Gram negative cocobacillus
Requires special media to grow
Bordetella pertussis
Gram negative
coccobacilli
Small, transparent
hemolytic colonies
on BG medium
Oxidase+,Urease-;
(B. parapertussis:
oxidase-, urease+; B.
brochosepticus: +/+)
Pertussis: epidemiology
pertussis is a
disease mainly
of children
Pertussis: course of disease
Pertussis: virulence factors
Pertussis toxin (pertussigen)*
Adenylate cyclase toxin
Tracheal toxin
Dermonecrotic toxin
Filamentous haemagglutinin*
Lipopolysaccharide
Pertussigen:
(an AB-toxin, oligopeptide)
Increases histamine and LPS
sensitivity
Increases IgE levels
T-cell lymphocytosis
Impairs phagocyte functions
ADP-ribosylates the Gi protein
(results in increased cAMP)
Pertussigen:
Structure
Pertussigen: dysregulation
of adenylate cyclase
Pertussis
toxin
Cholera
toxin
ATP
cAMP
Pertussis:
adenylate cyclase toxin
Activated by
calmodulin
Catalyses
ATP to
cAMP
conversion
cAMP
Pertussis
tracheal Toxin
A peptidoglycan-like molecule
Binds to ciliary epithelial cells
Inhibits ciliary movement
Kills ciliary ciliary epithelial cells
Causes pertussis
Pertussis:
dermonecrotic toxin
Strong vasoconstrictor
Causes ischemia
Synergizes with tracheal toxin
to causes tracheal necrosis
Pertussis:
filamentous haemagglutinin
Causes binding of bacteria to
ciliated epithelial cells
B. pertussis:
interactions with pneumocyte
B. pertussis:
lipopolysaccharide
Activates inflammatory
cytokines
Activates complement
In larger quantities, causes
shock and cardiac arrest
Pertussis:
diagnosis
 Based
on symptoms
 Culture
on Bordet-Gengou (potato-
glycerol-blood agar) medium
Laboratory Diagnosis
Specimens
Post / per nasal swab (no cotton
swab) / cough plate
Microscopy
Gram negative coccobacilli
Fluorescent antibody stain
Culture
Bordet – Gengou Medium
mercury drop pearl appearance
colonies
Identification
Microscopy & slide agglutination
Antibiotic
Erythromycin / Co-trimoxazole
Pertussis:
treatment
Erythromycin is the drug of choice
Vaccine is extremely effective
Immunization
1st Pertussis vaccinewhole cell
Combination vaccines
Diphtheria
Primary
Acellular vaccine now
used
D P
Pertussis
3 doses
Intervals of 4 - 6 wks
4th dose year after
T VACCINE
Tetanus
Booster School entry
A 2-year-old male is presented to you with a 10-day
history of persistent cough. The long cough spells are
followed by a deep breath. The cough often leads to
choking, vomiting, gasping and cyanosis. His pulse rate
is 190 (n: 100-160) and respiratory rate is 72 (n: 10-20).
Chest x-ray is normal. WBC counts are16,000/cm2 with
70% lymphocytes.
1.
2.
3.
4.
What is the organism and what are its physiologic
characteristics?
What are the pathogenic factors of this organism?
Why is there a preponderance of lymphocytes?
What is the epidemiology of and prophylaxis for the
disease?
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