Emerging ofptxP3 lineage inBordetella pertussis strains circulating in a population in northeastern Mexico
AbstractWe determined the molecular epidemiology ofBordetella pertussisisolates to evaluate its potential impact on pertussis reemergence in a population of Mexico. Symptomatic and asymptomatic cases were included. Pertussis infection was confirmed by culture and real-time polymerase chain reaction (PCR). SelectedB. pertussisisolates were further analysed; i.e. clonality was analysed by pulsed-field gel electrophoresis (PFGE) andptxP-ptxA, prn,fim2 andfim3 typing was performed by PCR and sequencing. Out of 11 864 analysed samples, 687 (5.8%) were positive for pertussis, with 244 (36%) confirmed by both culture and PCR whereas 115 (17%) were positive only by culture and 328 (48%) were positive only by PCR. One predominant clone (clone A,n= 62/113; 55%) and three major subtypes (A1, A2 and A3) were identified by PFGE. All 113 selected isolates had the allelic combinationptxP3-ptxA1.The predominant clone A and the three major subtypes (A1, A2 and A3) corresponded to the emerging genotypesptxP3-ptxA1-prn2-fim2-1-fim3-2 andptxP3-ptxA1-prn2-fim2-1-fim3-1. In conclusion, the presence of an endemic clone and three predominant subtypes belonging to the genotypesptxP3-ptxA1-prn2-fim2-1-fim3-2andptxP3-ptxA1-prn2-fim2-1-fim3-1were detected. This finding supports the global spread/expansion reported for these outbreaks associated genotypes.