Bordatella

Dr. R. Someshwaran, MD., Assistant professor, Dept. of Microbiology, KFMS&R

05/02/23 1

General characteristics

• Obligate aerobe• Gram negative cocco bacilli• Catalase positive• Oxidase positive• Indole negative• Sugars negative

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Bordetella species of clinical importance

B. pertussis

B. parapertussis

B. bronchosepticus

B. avium

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1. What is the organism and what are its physiologic characteristics?

2. What are the pathogenic factors of this organism?3. Why is there a preponderance of lymphocytes?4. What is the epidemiology of and prophylaxis for the

disease?

Q: 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.

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Bordetella pertussis

Causative agent of whooping cough

Gram negative cocobacillus

Requires special media to grow

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Bordetella pertussis

Gram negative coccobacilli

Small, transparent hemolytic colonies on BG medium

Oxidase+,Urease-; (B. parapertussis: oxidase-, urease+; B. brochosepticus: +/+)

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Pertussis: epidemiology

pertussis is a disease mainly of children

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Pertussis: course of disease

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Pertussis: virulence factors

Pertussis toxin (pertussigen)*Adenylate cyclase toxinTracheal toxinDermonecrotic toxinFilamentous haemagglutinin*Lipopolysaccharide

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Pertussigen:(an AB-toxin, oligopeptide)

Increases histamine and LPS sensitivityIncreases IgE levelsT-cell lymphocytosisImpairs phagocyte functionsADP-ribosylates the Gi protein (results in increased cAMP)

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Pertussigen:Structure

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Pertussigen: dysregulation of adenylate cyclase

Pertussistoxin

cAMPATPCholera toxin

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Pertussis: adenylate cyclase toxin

Activated by calmodulin

Catalyses ATP to cAMP conversion

Ac tox

Ac tox

Calm

cAMP

H2O

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Pertussistracheal Toxin

A peptidoglycan-like molecule

Binds to ciliary epithelial cells

Inhibits ciliary movement

Kills ciliary ciliary epithelial cells

Causes pertussis

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Pertussis:dermonecrotic toxin

Strong vasoconstrictor

Causes ischemia

Synergizes with tracheal toxin

to causes tracheal necrosis

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Pertussis:filamentous haemagglutinin

Causes binding of bacteria to

ciliated epithelial cells

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B. pertussis:interactions with pneumocyte

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B. pertussis: lipopolysaccharide

Activates inflammatory

cytokines

Activates complement

In larger quantities, causes

shock and cardiac arrest05/02/23 18

Pertussis: diagnosis

Based on symptoms

Culture on Bordet-Gengou (potato-

glycerol-blood agar) medium

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Laboratory Diagnosis

Specimens Post / per nasal swab (no cotton swab) / cough plate

Microscopy Gram negative coccobacilli

Culture Bordet – Gengou Medium mercury drop pearl appearance colonies

Antibiotic Erythromycin / Co-trimoxazole

Identification Microscopy & slide agglutination

Fluorescent antibody stain

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Pertussis: treatment

Erythromycin is the drug of choice

Vaccine is extremely effective

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Immunization

D P T VACCINE

Diphtheria Pertussis Tetanus

3 doses

Intervals of 4 - 6 wks

4th dose year after

School entryPrimary Booster

1st Pertussis vaccine- whole cell Acellular vaccine now used

Combination vaccines

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Thank you

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