title: Multilocus sequence typing of Bordetella pertussis based on surface protein genes.
abstract: Despite more than 50 years of vaccination, Bordetella pertussis has remained endemic in The Netherlands, causing epidemic outbreaks every 3 to 5 years. Strain variation may play a role in the persistence of B. pertussis and was studied by sequencing 15 genes coding for surface proteins, including genes for all five components of acellular pertussis vaccines: pertussis toxin (Ptx), pertactin (Prn), filamentous hemagglutinin, and fimbriae (Fim2 and Fim3). A low level of allelic variation was observed, confirming a recent evolutionary origin of B. pertussis. In modern isolates, polymorphism was observed only in prn, ptxS1, ptxS3, and tcfA. Polymorphism in ptxS1, ptxS3, and tcfA was used to categorize isolates in multilocus sequence types (MLSTs). Analysis of Dutch isolates from 1949 to 1999 revealed five MLSTs, which showed a highly dynamic temporal behavior. We observed significant changes in the MLSTs after the introduction of pertussis vaccination in The Netherlands. Epidemic years were found to be associated with the expansion of MLST-4 or MLST-5. MLST-5 showed a remarkable expansion from 10% in 1997 to 80% in 1999. The MLST analysis was extended to a number of widely separated geographic regions: Finland, Italy, Japan, and the United States. MLST-4 and MLST-5 were found to dominate in Italy and the United States. In Finland and Japan, MLST-3 and MLST-2, respectively, were predominant. Thus, although each region showed distinctive MLST frequencies, in three of the five regions MLST-4 and MLST-5 were predominant. These types may represent newly emerged, successful clones. The identification of highly successful clones may shed light on the question of how B. pertussis is able to maintain itself in vaccinated populations.
authors.affiliation: Laboratory for Infectious Diseases Research, National Institute of Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: Inge H M
authors.initials: IH
authors.lastname: van Loo
authors.forename: Kees J
authors.initials: KJ
authors.lastname: Heuvelman
authors.forename: Audrey J
authors.initials: AJ
authors.lastname: King
authors.forename: Frits R
authors.initials: FR
authors.lastname: Mooi
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D001886:Bordetella pertussis / Q000145:classification* / Q000235:genetics; D014644:Genetic Variation; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009426:Netherlands / Q000453:epidemiology; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D014917:Whooping Cough / Q000453:epidemiology* / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins