Microbiology · MU Sofia

63. Bordetella pertussis.

Covers the morphology, growth requirements and fermentation profile of Bordetella pertussis, then its human-only reservoir, airborne spread and vulnerable groups. Lists the main virulence factors in a table, followed by the pathogenesis steps and the three clinical stages of whooping cough. Ends with diagnostic specimens and tests, macrolide treatment, and vaccination schedule with prophylaxis for close contacts.

Inside: 9 sections · 5 labelled pictures · 1 table · 14 flashcards · 2 min

Topic 63 of 113 in the MU Sofia syllabus for Microbiology (Dental Medicine, Year 2). The free AceMed note covers it in 9 sections, about 268 words (2 min of reading), with 14 flashcards.

In this note

  1. Bordetella pertussis
  2. General Characteristics
  3. Epidemiology
  4. Virulence Factors
  5. Pathogenesis
  6. Clinical Features of Pertussis (3 stages)
  7. Diagnosis
  8. Treatment
  9. Prevention

General Characteristics

  • Gram status: Gram-negative coccobacilli
  • Oxygen requirement: Obligate aerobes
  • Motility: Non-motile
  • Capsulated: Yes (small capsule)
  • Spores: Non-spore forming
  • Growth needs: Highly fastidious → Requires enriched medium (e.g. Bordet-Gengou agar or Regan-Lowe agar)
  • Fermentation: Forms acid (not gas) from glucose and lactose
  • Temperature: Grows at 35–37°C with prolonged incubation

Epidemiology

  • Reservoir: Humans (strictly human pathogen)
  • Transmission: Airborne respiratory droplets (especially during paroxysmal stage)
  • Target: Primarily infants and unvaccinated children
  • Incubation period: 7–10 days

Pathogenesis

  1. 1. Colonization of upper respiratory tract ciliated epithelium via adhesins
  2. 2. Toxin production damages epithelial cells → Impaired mucociliary clearance
  3. 3. Tracheal cytotoxin kills cilia-bearing cells → intense coughing
  4. 4. PT disrupts immune signaling → systemic symptoms
  5. 5. Persistent infection leads to accumulation of mucus and intense paroxysmal coughing

Clinical Features of Pertussis (3 stages)

  1. 1. Catarrhal stage (1–2 weeks)
  • Cold-like symptoms: rhinorrhea, low-grade fever, mild cough
  • Highly contagious
  1. 2. Paroxysmal stage (2–6 weeks)
  • Paroxysms of intense coughing (up to 50 times/day)
  • Whooping sound (high-pitched gasp) after fits
  • Post-tussive vomiting, cyanosis possible
  1. 3. Convalescent stage (weeks–months)
  • Gradual recovery, secondary infections may occur
  • Cough may persist

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