Institute of Virology, Vaccines and Sera Torlak, Serbia
Dr Tatjana Plješa received her medical education, specialization in Microbiology and parasitology and postgraduate studies in Clinical and Experimental Bacteriology at the Medical Faculty, University of Belgrade, Serbia. Dr Plješa is the author of over 30 publications in the field of microbiology and immunology. She was Production Director in the Institute of Virology, Vaccines and Sera Torlak and now she works in bacterial vaccine production area. Prior to this, Dr Plješa was the Head of Vaccine Production Department, where she managed the production of pertussis vaccine. She has 10 years of experience in biotechnology, quality control, research and technology development.
Resurgence of pertussis has been observed in many countries with long vaccination history. Moreover, in these countries antigenic divergence in pertussis toxin (Ptx) and pertactin (Prn) has been found between Bordetella pertussis vaccine strains and clinical isolates. At the other side, the incidence of pertussis in Serbia has been decreasing since the introduction of whole cell pertussis vaccine vaccination in 1957. The aim of this study was to analyze B. pertussis vaccine strains and isolates circulating between 1953 and 2011 in Serbia and to compare them with other countries data to study possible effect of the inclusion of “contemporary” strains in the vaccine composition on temporal trends in B. pertussis population. Four vaccine strains and 77 isolates collected from 1953 to 2011 were studied. The methods included serotyping of fimbriae (Fim), genotyping of pertactin (prn) and pertussis toxin S1 subunit (ptxA). The Serbian vaccine strains showed differences in ptxA and prn. Shift from ptxA2 to ptxA1 has been observed in isolates since the late of 1960s. Re-appearance of the ptxA2 allele followed an addition of the two strains harboring ptxA1 in the vaccine in 1985. The allele prn1 was predominant among the Serbian isolates. The prn2 allele was only found in one strain isolated in 1984 and five strains isolated after 2000. Serotype Fim2.3 disappeared before 1980 and serotype Fim2 became predominant since then. The results of this present study indicate that the B. pertussis population in Serbia is different from other vaccinated populations and that this difference may be related to the vaccine used, so it is possible that inclusion of “contemporary” strains in the vaccine composition could have a positive effect on changes in B. pertussis population and low incidence of the disease.