Basic features of Bordetella
- Gram-negative coccobacilli
- Non-spore forming
- Obligate aerobes
Biochemistry and growth
- Very fastidious
- Do not ferment carbohydrates
- Inhibited by fatty acids (need media that absorb the fatty acids to grow)
- Difficult to culture; isolated on:
- Bordet-Gengou agar (blood, potato extract, and glycerol plus antibiotics and nicotinamide)
- Regan-Lowe medium (charcoal with defibrinated horse blood)
- B. pertussis (most important): causes pertussis (whooping cough)
- B. parapertussis: can also cause pertussis
- B. bronchiseptica: rare in humans, but can infect immunocompromised hosts
- Incidence worldwide: 24 million cases per year
- Deaths worldwide: approximately 161,000 per year
- Incidence in the United States: 15,000 cases in 2018
- Vaccination reduces the incidence significantly in young children, but does not confer lifelong immunity.
- Cyclical epidemics occur every 2–5 years.
- Disease is less severe in adolescents and adults than in young children.
- No known environmental reservoirs
- Transmitted by respiratory droplets
- Many household contacts can have asymptomatic or very mild disease, frequently undiagnosed.
- Incubation period is 1 to 3 weeks (most commonly 7–10 days).
- The 1st step is inhalation.
- Bacteria adhere to the ciliated epithelium of the nasopharynx and upper respiratory tract by various protein adhesins.
- Cause tissue damage and loss of protective epithelial cells by toxin production
- Results in microaspiration and cough
- Fatal cases are associated with:
- Necrotizing bronchiolitis
- Alveolar hemorrhage
- Fibrinous edema
- Intracellular bacteria in alveolar macrophages and ciliated epithelium (evade intracellular digestion)
- Filamentous hemagglutinin pili:
- Allow for attachment to ciliated, respiratory epithelium
- Pertussis toxin (A/B toxin):
- Ribosylates (inhibits) guanine nucleotide-binding protein (Gi)
- Increases cyclic adenosine monophosphate (cAMP)
- Impairs phagocytosis
- Causes lymphocytosis
- Adenylate cyclase toxin:
- Increases cAMP similar to the Bordetella anthracis EF-2 toxin
- Induces apoptosis of macrophages
- Tracheal toxin:
- Induces nitric oxide gas production
- Damages respiratory epithelium
- Pertussis is a form of bronchitis.
- In children, classically has 3 stages:
- Catarrhal stage: congestion, coryza (runny nose), conjunctivitis, low-grade fevers (1–2 weeks)
- Paroxysmal stage (2–8 weeks):
- Severe coughing episodes on expiration
- “Whoops” on inspiration (whooping, paroxysmal cough)
- Post-tussive vomiting
- In infants, often presents with apnea instead of coughing paroxysms
- Convalescent stage: decreased frequency of coughing (4 weeks to months)
- In adults and adolescents:
- Often milder than in children
- Prolonged cough (> 2 weeks) is frequently the only symptom.
- Also known as the “100-day cough”
- Nasopharyngeal swab or aspiration
- Cotton-tipped swabs should not be used because they contain fatty acids toxic to B. pertussis.
- Polyester or calcium alginate swabs should be used instead.
- Specimen should be obtained from the posterior nasopharynx.
- Culture (on special media)
- Polymerase chain reaction (PCR)
- Serology: primarily research applications
- Acellular vaccine
- Component of the diphtheria, tetanus, and acellular pertussis (DTaP) combined vaccine
- Cornea P., & Lipsky B. (2020). Pertussis infection: Epidemiology, microbiology, and pathogenesis. UpToDate. Retrieved January 4, 2021, from https://www.uptodate.com/contents/pertussis-infection-epidemiology-microbiology-and-pathogenesis?search=bordetella&source=search_result&selectedTitle=4~41&usage_type=default&display_rank=4
- Cornea P., & Lipsky B. (2020). Pertussis infection in adolescents and adults: Clinical manifestations and diagnosis. UpToDate. Retrieved January 4, 2021, from https://www.uptodate.com/contents/pertussis-infection-in-adolescents-and-adults-clinical-manifestations-and-diagnosis?search=bordetella&source=search_result&selectedTitle=1~41&usage_type=default&display_rank=1
- Guiso N. (2015). Bordetella pertussis. In Nicholson LK, & Janoff EN. (Eds.), Mucosal Immunology (4th ed.) https://www.sciencedirect.com/topics/medicine-and-dentistry/bordetella-pertussis