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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
05/02/23 2
Bordetella species of clinical importance
B. pertussis
B. parapertussis
B. bronchosepticus
B. avium
05/02/23 3
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.
05/02/23 4
Bordetella pertussis
Causative agent of whooping cough
Gram negative cocobacillus
Requires special media to grow
05/02/23 5
Bordetella pertussis
Gram negative coccobacilli
Small, transparent hemolytic colonies on BG medium
Oxidase+,Urease-; (B. parapertussis: oxidase-, urease+; B. brochosepticus: +/+)
05/02/23 6
Pertussis: epidemiology
pertussis is a disease mainly of children
05/02/23 7
Pertussis: course of disease
05/02/23 8
Pertussis: virulence factors
Pertussis toxin (pertussigen)*Adenylate cyclase toxinTracheal toxinDermonecrotic toxinFilamentous haemagglutinin*Lipopolysaccharide
05/02/23 9
Pertussigen:(an AB-toxin, oligopeptide)
Increases histamine and LPS sensitivityIncreases IgE levelsT-cell lymphocytosisImpairs phagocyte functionsADP-ribosylates the Gi protein (results in increased cAMP)
05/02/23 10
Pertussigen:Structure
05/02/23 11
Pertussigen: dysregulation of adenylate cyclase
Pertussistoxin
cAMPATPCholera toxin
05/02/23 12
Pertussis: adenylate cyclase toxin
Activated by calmodulin
Catalyses ATP to cAMP conversion
Ac tox
Ac tox
Calm
cAMP
H2O
05/02/23 13
Pertussistracheal Toxin
A peptidoglycan-like molecule
Binds to ciliary epithelial cells
Inhibits ciliary movement
Kills ciliary ciliary epithelial cells
Causes pertussis
05/02/23 14
Pertussis:dermonecrotic toxin
Strong vasoconstrictor
Causes ischemia
Synergizes with tracheal toxin
to causes tracheal necrosis
05/02/23 15
Pertussis:filamentous haemagglutinin
Causes binding of bacteria to
ciliated epithelial cells
05/02/23 16
B. pertussis:interactions with pneumocyte
05/02/23 17
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
05/02/23 19
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
05/02/23 20
Pertussis: treatment
Erythromycin is the drug of choice
Vaccine is extremely effective
05/02/23 21
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
05/02/23 22
Thank you
05/02/23 23