Surveillance of Circulating Bordetella pertussis Strains in Europe during 1998 to 2015

Abstract

One reason for increased pertussis incidence is the adaptation of <i>Bordetella pertussis</i> to vaccine-induced immunity by modulating its genomic structure. This study, EUpert IV, includes 265 isolates collected from nine European countries during 2012 to 2015 (<i>n</i> = 265) and compares the results to previous EUpert I to III studies (1998 to 2009). The analyses included genotyping, serotyping, pulsed-field gel electrophoresis (PFGE), and multilocus variable-number tandem-repeat analysis (MLVA). Genotyping results showed only small variations among the common virulence genes of <i>B. pertussis</i> The frequencies of serotypes Fim2 and Fim3 varied among the four collections. Genomic analyses showed that MLVA type 27 increased to 80% between the periods of 1998 to 2001 and 2012 to 2015. Two PFGE profiles, BpSR3 (29.4%) and BpSR10 (27.2%), constituted more than 50% of the circulating isolates in the present collection. Our study indicates that the European <i>B. pertussis</i> population is changing and became more homogenous after the introduction of acellular pertussis vaccines.