Introduction, background, pathogenesis, lab diagnosis, prevention and treatment

1. Bordetella
By
THENARUVI S

2. INTRODUCTION
• Bordetella is highly fastidious, very small, gram negative
coccobacillus, described first by Bordet and Gengou in 1906. lt is a
non-fermenter, belongs to family Alcaligenaceae.
• It comprises of several species
– Bordetella pertussis: It causes whooping cough in children, a
highly contagious vaccine preventable bacterial disease,
characterized by paroxysmal cough ending in a high-pitched
inspiratory sound described as "whoop".
– B. parapertussis: It causes milder form of whooping cough.
– B. bronchiseptica: It is a pathogen of domestic animals that
causes kennel cough in dogs, atrophic rhinitis and pneumonia in
pigs, and pneumonia in cats. Rarely, respiratory infections in
humans have been reported.
– B. avium: It causes respiratory disease in turkeys.
– B. hinzii and B. holmesii: They occasionally cause bacteremia
in immunocompromised people.

3. Bordetella pertussis
• B. pertussis causes a violent paroxysmal productive cough in
children called whooping cough or 100 days fever.
• They are very small, gram negative coccobacilli.
• They are more fastidious species, grow slowly in culture. Strictly
aerobes.
• The organisms are non-motile and oxidize amino acids, but they do
not ferment carbohydrates.
• These species are highly susceptible to toxic substances and
metabolites, they require media supplemented with charcoal, starch,
blood, or albumin to absorb the toxic substances.
• Many virulence factors responsible for adherence to eukaryotic cells
and production of localized tissue destruction

4. Adhesions
Virulence factor Biological Effect
Filamentous
hemagglutinin
Required for binding to sulfated glycoproteins on membranes
of ciliated cells in trachea; highly immunogenic
Pertactin As with filamentous hemagglutinin
Pertussis toxin S2 subunit binds to glycolipid on surface of ciliated
respiratory cells; S3 subunit binds to ganglioside on surface of
phagocytic cells
Fimbriae Bind to mammalian cells; role in disease is unknown but
stimulate humoral Immunity
Virulence Factors Associated with Bordetella pertussis

5. Toxins
Virulence factor Biological Effect
Pertussis toxin S1 subunit inactivates G1α, the membrane surface protein that controls
adenylate cyclase activity; uncontrolled expression leads to increased
cyclic adenoside monophosphate levels; toxin inhibits phagocytic killing
and monocyte migration
Adenylate cyclase/
hemolysin toxin
Increases intracellular level of adenylate cyclase; inhibits phagocytic killing
and monocyte migration
Dermonecrotic toxin Causes dose-dependent skin lesions or fatal reactions in experimental
animal model; role in disease is unknown
Tracheal cytotoxin A peptidoglycan fragment that kills ciliated respiratory cells and
stimulates the release of interleukin-1 (fever)
Lipopolysaccharide Two distinct lipopolysaccharide molecules with either lipid A or lipid X;
activates alternate complement pathway and stimulates cytokine release;
role in disease is unknown

6. Epidemiology

7. Pathogenesis

8. Clinical manifestation

9. Whooping Cough
• Each paroxysm consists of bursts of 5-10 repetitive violent
spasmodic coughs, often within a single expiration which
ends with an audible sound or whoop.
• Whoop occurs due to rapid inspiration against a closed
glottis at the end of the paroxysm
– Paroxysms may be precipitated by noise, eating or
physical contact. In between the paroxysms, patient may
appear to be normal.
– The frequency of paroxysms, varies widely, from severaI
per hour to 5- 10 per day.
– Episodes are often worse at night.
– During a spasm there may be visible neck
vein distension, bulging of eyes, tongue protrusion
and cyanosis.
– Weight loss may be seen, but fever is uncommon.

10. Lab diagnosis
• Specimen: Nasopharyngeal secretions collected by alginate swabs
• Direct smear: Gram-negative coccobacilli and pus cells
• Culture:
– Regan-Lowe medium and Bordet-Gengou agar
– Produces mercury drops or bisected pearls colony
• Culture smear: Reveals small, ovoid gram-negative coccobacilli
arranged in 'thumb print' appearance
• Detection of serum antibodies: By enzyme immunoassays
• PCR: Detecting IS481 and PT promoter region genes
• Typing of B.pertussis: By serotyping and genotyping

11. A. Female infant suffering from pertussis;
B. Colonies of Bordetella pertussis on Regan-Lowe agar (mercury drops
appearance);
C. Gram-stained smear of Bordetella pertussis (thumb print appearance)

12. Treatment, Prevention, and Control
• Treatment with macrolide (i.e., azithromycin, clarithromycin) is
effective in eradicating organisms and reducing length of infectious
stage
• Azithromycin is used for prophylaxis
• Vaccines containing inactivated pertussis toxin, filamentous
hemagglutinin, and pertactin are highly effective
• Pediatric vaccine administered in five doses (at ages 2, 4, 6, and 15
to 18 months, and between ages 4 and 6 years); adult vaccine
administered at ages 11 to 12 years and between 19 to 65 years

13. OTHER BORDETELLA SPECIES
• B. parapertussis is responsible for causing 10% to 20% of the
cases of mild pertussis occurring annually in the United States.
• B. bronchiseptica causes respiratory disease primarily in animals
but has been associated with human respiratory tract colonization
and bronchopulmonary disease.
• Investigators at the Centers for Disease Control and Prevention in
Atlanta reported that B. holmesii is primarily associated with
septicemia.

14. Thank you