Population dynamics and antigenic drift of Bordetella pertussis following whole cell vaccine replacement, Barcelona, Spain, 1986–2015

MLVA; PFGE; Vacuna contra la tos ferinaMLVA; PFGE, Vacuna contra la tos ferinaMLVA; PFGE; Pertussis vaccineAmong the factors associated with the resurgence of whooping cough, special emphasis has been given to pathogen adaptation after the introduction of the acellular vaccine (ACV). To assess the impact of the vaccine transition strategy from whole-cell vaccine (WCV) to ACV on population dynamics of Bordetella pertussis in Barcelona (Spain), we studied 339 isolates collected from 1986 to 2015 by PFGE and multi-locus variable-number tandem repeat analysis (MLVA). Additionally, allelic variants for the pertussis toxin and its promoter, pertactin, type 3 fimbriae and fimbrial serotyping were assessed to determine its antigenic drift. A shift was observed in the B. pertussis population as well as in its antigenic profile concurrently with the introduction of ACV in Barcelona. Four out of the five most prevalent PFGE profiles were replaced by new profiles following the ACV introduction. MLVA type 27 was the dominant genotype, and its frequency increased from 25% to 79.3% after WCV replacement. Antigen typing demonstrated the emergence of prn2, ptxP3, fim3-2 and a shift from the fimbriae 3 to the fimbriae 2 serotypes after the ACV introduction. Our findings support the presence of population and antigenic dynamic changes in B. pertussis likely driven by the introduction of ACV.This work was supported by the “Ministerio de Economía y Competitividad”, “Instituto de Salud Carlos III”, and cofinanced by the European Regional Development Fun (ERDF) “A Way to Achieve Europe” (Spanish Network for Research in Infectious Diseases [grant number RD16/0016/0003], “Fondo de Investigación Sanitaria [grant number FIS PI18/ 00703]). AMC is supported by the “Agència de Gestió d'Ajuts Universitaris i de Recerca, Generalitat de Catalunya” [grant number 2018FI_B_00855]