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Small mutations in Bordetella pertussis are associated with selective sweeps
Marjolein van Gent1, Marieke J Bart, Han G J van der Heide
1Laboratory for Infectious Diseases and Screening, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
Plos One
|October 3, 2012
Summary
Pertussis (whooping cough) is resurging due to pathogen adaptation. Small genetic changes in Bordetella pertussis, driven by vaccination, have led to population-level shifts and persistence of this vaccine-preventable disease.
Area of Science:
- Microbiology
- Genomics
- Epidemiology
Background:
- Pertussis (whooping cough) remains prevalent despite vaccination, suggesting pathogen adaptation.
- Allelic variations in virulence genes like ptxA, prn, fim3, and ptxP are observed in Bordetella pertussis.
Purpose of the Study:
- To investigate the impact of over 60 years of vaccination on the Dutch Bordetella pertussis population.
- To analyze genetic changes and selective sweeps in Bordetella pertussis strains.
Main Methods:
- Phylogenetic analysis of Bordetella pertussis strains.
- Genomic comparison of 11 Dutch strains.
- Analysis of temporal trends in virulence gene frequencies (ptxA, prn, fim3, ptxP).
Main Results:
- At least four selective sweeps occurred in the Dutch Bordetella pertussis population between 1949 and 2010.
- Small mutations, including single nucleotide polymorphisms (SNPs), in ptxA, prn, fim3, and ptxP were associated with these sweeps.
- Stepwise clonal adaptation was observed, with limited evidence for gene acquisition or large deletions driving adaptation.
Conclusions:
- Bordetella pertussis exhibits fine-tuning adaptation to persist under vaccination pressure.
- Small genetic mutations can significantly alter bacterial pathogen populations over relatively short periods (6-19 years).
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