Bordetella pertussis – the returning pathogen

Bordetella pertussis is a non-motile, Gram-negative coccobacillus belonging to the genus Bordetella. It is the causative agent of pertussis – a respiratory tract infection also known as whooping cough or 100-days’ cough. A similar bacterium, Bordetella parapertussis, is responsible for a proportion of pertussis cases, which are distinguished by milder symptoms. Two major virulence factors of Bordetella pertussis are adhesins (filamentous hemagglutinin and fimbriae) which facilitate tracheal colonization – the first step leading to infection. In pediatric population B. pertussis infection tends to take a highly unpredictable and sometimes fatal course. Antimicrobial drugs of macrolide class are the mainstay of therapy mainly due to their superb activity against Bordetella pertussis. However, antibiotic administration is ineffective in alleviating symptoms of whooping cough. Therefore, in the first half of the 20th century there was a collective effort of scientific community to create an efficient vaccine against B. pertussis. These endeavors proved fruitful and culminated in the implementation of vaccination programs since 1940s. Despite the widespread availability of vaccines, pertussis remains a significant cause of children morbidity to this day. Epidemiological data gathered in Poland during the last 10 years clearly imply that the disease incidence is steadily increasing. Furthermore, pertussis outbreaks, which happened every few years in the past, nowadays occur almost every other year. The reasons behind the alarming resurgence of pertussis are multifold, but two elements are presumed to play a key role: the waning immunity of adolescents who were vaccinated many years ago; and the parents’ reluctance to vaccinate their offspring. On account of the steady growing number of pertussis cases, the definite causes of the current epidemiological state ought to be determined and an adequate approach to combat theses reasons must be undertaken