Epidemiological typing of Bordetella pertussis isolates: recommendations for a standard methodology.

Pertussis is re-emerging in vaccinated populations, and to gain insight into the reasons for this development population-based studies are necessary. Unfortunately, various techniques are used to study Bordetella pertussis populations, hampering comparison between studies. A standard methodology for epidemiological typing of Bordetella pertussis isolates is proposed which is based on serotyping, pulsed-field gel electrophoresis and gene typing. Such a standard approach will allow comparisons between studies performed in different laboratories. Comparisons may reveal whether the epidemiological differences observed between countries are due for instance to different Bordetella pertussis populations or different vaccines used.