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Bordetella

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Bordetella

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  1. Bordetella

  2. Species • B.pertussis – wooping cough • B.parapertussis – milder type • B.bronchiseptica – 0.1% cases • B.avium – respiratory disease of birds

  3. Bordetellapertussis • Aerobic, Gram negative coccobacillus • Non-motile & non-sporing • Capsulated • Specific to humans • Colonizes the respiratory tract • Bipolar metachromatic granules- toluidine blue

  4. Thumb print appearance

  5. Cultural characteristics • Bordet- Gengou glycerine-potato-blood agar • Charcoal blood agar • Borget-Gengou media– bisected pearls or mercury drops. • Confluent growth– aluminium paint appearance

  6. Whooping Cough / Pertussis • Also known as Pertussis • Outbreaks first described in the 16th Century • Major cause of childhood fatality prior to vaccination

  7. Antigenic structure 1.Agglutinogens • 1-14; associated with capsule • B.pertusis - 1-6, 7 & 13 • Adhesion to respiratory epithelial cells 2. LPS 3. Heat labile toxin (HLT) 4.Tracheal cytotoxin (TCT) 5. Dermonecrotictoxin

  8. 6. Filamentous hemagglutinin • FHA is a filamentous structure that measures about 2 nm wide and 50 nm long. • FHA is thought to be the major colonizing factor for B. pertussis as it promotes attachment to the upper respiratory tract and the trachea.

  9. 7. Pertactin • OMP antigen • Virulent strains • Antibody are seen in blood of children after infection or immunisation • Acellular pertussis vaccine

  10. 8.Pertusis Toxin • Pathogenesis of whooping cough • Surface of bacillus and secreted into medium • A-B structure • A- enzymatically active moiety B- Binding component Toxoided

  11. Pertusis Toxin structure

  12. 9. AdenylateCyclase Toxin • Invasive toxin • Activated by host cell calmodulin • Impairment of immune effector cells

  13. Transmission • Pertussis is highly contagious, with an 80% secondary attack rate among susceptible persons • Pertussis-- respiratory droplets, but direct contact with respiratory secretions from infected individuals may also lead to the disease.

  14. PATHOGENESIS

  15. Clinical Features • Incubation period 4-21 days • 3 Stages • 1st Stage- Catarrhal Stage 1-2 weeks • 2nd Stage- Paroxysmal Stage 1-6 weeks • 3rd Stage- Convalescent Stage weeks-months

  16. Lab diagnosis • Specimen – Pernasal swab, Nasopharyngeal aspirtaes, West’s post nasal swab • Microscopy – Gram stain, FAT • Culture – Bordet-Gengou media, Charcoal blood agar. • Cough plate method • Serology – ELISA, IFT

  17. COMPLICATIONS • Sub conjunctival hemorrhage • Bronchopneumonia • Lung collapse • Convulsions • Coma

  18. Treatment • Antibiotic therapy • Erythromycin • Azithromycin and clarithromycin • Ampicilin

  19. Prophylaxis

  20. Pertussis Vaccine • 1st Pertussis vaccine- whole cell • Acellular vaccine now used – PT, FHA, Agglutinogens 1,2 & 3 • Combination vaccines • Tetanus, Diptheria, Hepatitis B http://www.nfid.org/publications/clinicalupdates/pediatric/pertussis.html

  21. Strain Variation • B. pertussis population has changed significantly since vaccine introduction • Adaptation to vaccine • Antigenic divergence

  22. Conclusions • Reemerging in adult and adolescent populations as worldwide vaccination rates increase • High vaccination rates not enough • Better vaccine development needed