Resemblance and divergence: the "new" members of the genus Bordetella.

Bordetella pertussis, the etiological agent of whooping cough, belongs to the bacterial pathogens first described in the so-called golden era of microbiology more than 100 years ago. In the course of the following decades, several other closely related pathogens were described which are nowadays classified in the genus Bordetella together with B. pertussis. These are the human and animal pathogens B. parapertussis, B. bronchiseptica and B. avium which are of high medical or veterinary interest, and which, together with B. pertussis, are referred to as the "classical" Bordetella species. Only in the past 15 years, several additional species were classified in the genus, frequently isolated from patients with underlying disease, animals or from the environment. Very little is known about most of these bacteria. In the present review, the current knowledge about these "new" Bordetella species is briefly summarized.