Bordetella

Bordetella is a genus of small, Gram-negative, aerobic, non-motile coccobacilli that colonize the respiratory tract of humans and animals. The group includes several clinically important species, most notably Bordetella pertussis, the primary human pathogen that causes pertussis (whooping cough). Other species such as B. parapertussis, B. bronchiseptica, B. holmesii and B. avium are associated with respiratory infections in humans or animals.

Bordetella species differ in host range and disease. B. pertussis and B. parapertussis cause pertussis-like illness in humans, with B. pertussis producing the classical whooping cough. B. bronchiseptica infects a broad range of animals and can cause bronchitis or pneumonia; in humans it may cause respiratory infections, especially in those with underlying lung disease. B. avium is primarily an avian pathogen, while B. holmesii has been linked to respiratory infections and, less commonly, bacteremia.

Pathogenesis is driven by virulence factors that promote adherence to and damage of the airway epithelium. Adhesins such as filamentous hemagglutinin, pertactin and fimbriae facilitate attachment, while toxins including pertussis toxin and adenylate cyclase toxin disrupt host cellular signaling and ciliary clearance. The BvgAS regulatory system controls expression of virulence determinants. These factors enable prolonged coughing fits and impaired mucociliary clearance, particularly in pertussis.

Diagnosis relies on culture on selective media such as Bordet-Gengou or Regan-Lowe, supported by PCR from nasopharyngeal specimens. Serology may aid in epidemiology but is not routine for acute diagnosis. Treatment typically involves macrolide antibiotics, which reduce transmission if started early.

Prevention centers on vaccination with acellular pertussis vaccines (DTaP and Tdap), which reduce disease severity and transmission. Whole-cell vaccines were used in the past. Vaccination, along with surveillance and infection control, remains the cornerstone of Bordetella-related disease control.