Description
Four species, Bordetella pertussis, B. parapertussis, B. bronchiseptica and B. avium belong to the bacterial genus of Bordetella. These bacteria are ubiquitous, small (0.2 – 0.5 µm), gram-negative obligatory aerobic coccoid single or paired bacteria. The ideal temperature for reproduction is 35 - 37 °C. B. pertussis and B parapertussis are human pathogens causing whooping cough (pertussis) and a milder form, which is less common (atypical pertussis). The other two species mostly cause respiratory diseases in warm-blooded animals. However, in rare cases (e.g. close contact with animals) B. bronchiseptica is an opportunistic secondary human pathogen in case of infections like bronchitis, pneumonia or wound infections. Even though there are phenotypic differences between the three human pathogenic Bordetella species, their DNA is 72-94% homologous. Therefore, it is currently being discussed whether to combine them in a single species or three subspecies of one species.
Bordetella pertussis causes whooping cough, a worldwide infectious disease that is transmitted from person to person by droplet infection. Especially children at the age of 0-4 years are affected, and the mortality of infected infants is high.
The attachment of B. pertussis to the tuft of ciliated cells in the mucosa of the human respiratory tract is mediated by adhesins. An important adhesion protein and an equally important immunogen is the so called filamentous hemagglutinin (FHA). Colonizing of the respiratory tract and establishment of infection are facilitated by the synergistic action of several virulence factors.
A significant virulence factor is pertussis toxin (PT), which is exclusively synthesized and secreted by B. pertussis. Multiple biologic effects like leukocytosis, lymphocytosis, mitogenicity and increased sensitivity to histamine are caused by PT.
The typical whooping cough can be divided into three stages: the catarrhal phase, the convulsivum (paroxysmal) phase, and the decrementi phase.
The ELISA technique is the most commonly chosen method for B. pertussis antibody detection.
A whole-cell antigen preparation of B. pertussis is used in the Bordetella pertussis IgM ELISA