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[Dynamics of changes in pathogenic characteristics of Bordetella pertussis strains]

N U Mertsalova, O Iu Borisova, A S Shinkarev

    Zhurnal Mikrobiologii, Epidemiologii I Immunobiologii
    |January 26, 2010
    PubMed
    Abstract

    Insights

    Pertussis strains have adapted to increased vaccination, showing increased virulence and toxicity. Genotyping reveals a shift towards a dominant "non-vaccine" allele, indicating significant adaptive changes in the Bordetella pertussis population.

    Area of Science:

    • Microbiology
    • Epidemiology
    • Immunology

    Background:

    • Pertussis, caused by Bordetella pertussis, remains a significant public health concern despite widespread vaccination.
    • Understanding the evolution of B. pertussis strains is crucial for effective disease control and vaccine development.

    Purpose of the Study:

    • To investigate the pathogenic and genotypic characteristics of B. pertussis strains isolated during different epidemic phases.
    • To analyze adaptive changes in B. pertussis in response to vaccination pressure.

    Main Methods:

    • Studied B. pertussis strains isolated in Moscow from 1967-2005.
    • Assessed virulence (LD50), leukocytosis-stimulating (LS units), and histamine-sensitizing (HSD50) activities.
    • Performed genotyping to analyze ptxA alleles.

    Main Results:

    • Strains from 1967-1971 and 2001-2005 exhibited high virulence and toxicity.
    • Strains from 1980-1985 showed reduced virulence and toxicity.
    • Genotyping revealed the displacement of vaccine alleles (ptxA2, ptxA4) by the non-vaccine allele (ptxA1).

    Conclusions:

    • B. pertussis has undergone adaptive evolution, driven by vaccination, leading to increased virulence and toxicity.
    • The emergence and dominance of the ptxA1 allele are associated with these pathogenic changes.
    • A genotypically homogenous population with high virulence strains now dominates.

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