A study on the genetic analysis of clinical isolates and vaccine strains of Bordetella pertussis by pulsed-field gel electrophoresis (PFGE)

Considering the circulation of Bordetella pertussis clinical strains among populations with high vaccination coverage, it is necessary to have a proper understanding of this bacterium causing whooping cough. Various techniques, which are available for studying B. pertussis, can facilitate a proper comparison between different populations. We genotypically analyzed a collection of two vaccine strains used for the production of killed pertussis vaccine during 2000-2014 at Razi Vaccine and Serum Research Institute, Karaj, Iran. Ten clinical and two reference (Tohama 1 and 18323) strains were used by means of pulsed-field gel electrophoresis (PFGE). The genetic profiles of the vaccine master and working seeds showed no significant changes in the frequency of fingerprint types in the vaccine strains; also, the homogeneity of the profiles was demonstrated. However, the clinical isolates showed heterogeneity in the genetic profiles. In addition, serotyping was performed with monoclonal antisera to agglutinogens 2 and 3. Analysis of the fimbriae showed that all ten clinical strains expressed Fim3.