Bordetella

Bordetella genus comprises five species, four of which cause infections of the upper respiratory tract in different host organisms. Bordetella pertussis is an obligate human pathogen and the only organism of major clinical significance within this genus; it causes whooping cough in infants and young children. A closely related organism, B. parapertussis can also cause a milder form of bronchitis. B. bronchosepticus, another member, is the causative agent of respiratory diseases in cats and swine, but can cause broncho-pulmonary symptoms in severely immunosupressed individuals.

Bordetella pertussis
Morphology and physiology:- is a small Gram-negative coccobacillus. It is aerobic and grows best at 35-37°C. Bordetella species, including B. pertussis and B. parapertussis, are fastidious and difficult to grow on ordinary media. B. pertussis requires supplemental growth factors including charcoal, blood, and starch. Media such as Bordet-Gengou, which contains potato starch, and charcoal-based media typically are used for culturing the organism. B. pertussis is oxidase positive but urease negative, while B. parapertussis is oxidase negative and urease positive. B. bronchosepticus is positive for both enzymes.

Epidemiology:- Whooping cough (Pertussis) is a worldwide infectious disease caused by Bordetella pertussis. It is a respiratory disease occurring after transmission of the bacteria from person-to-person in airborne droplets expelled by severe coughing. Since no animal reservoir for B. pertussis, the bacterium appears unable to survive in the environment for long periods of time. The bacteria are highly infectious and unprotected close-contacts are liable to become infected. The severity of disease is also age-related. Incidence is highest in children under five, except where infant vaccination programs have been effective.