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Characterization of Bordetella pertussis strains of recent isolation

P Stefanelli1, L De Marzi, L Robino

  • 1Laboratory of Bacteriology and Medical Mycology, Istituto Superiore di Sanità, Rome, Italy.

The New Microbiologica
|July 29, 1999
PubMed

Insights

This study identified optimal methods for isolating and characterizing Bordetella pertussis strains from children. Most pertussis strains belonged to serotype 1,3 and a predominant pulsetype (PTA), with no erythromycin resistance observed.

Area of Science:

  • Microbiology
  • Vaccinology
  • Infectious Diseases

Background:

  • Pertussis, caused by Bordetella pertussis, remains a significant public health concern.
  • Evaluating new acellular pertussis vaccines requires robust methods for bacterial strain recovery and characterization.
  • Understanding circulating Bordetella pertussis strains is crucial for vaccine efficacy assessment.

Purpose of the Study:

  • To establish optimal conditions for the recovery and characterization of Bordetella pertussis strains.
  • To analyze the characteristics of Bordetella pertussis isolates from children in Italy during a vaccine trial.
  • To assess the genetic relatedness and antibiotic susceptibility of circulating strains.

Main Methods:

  • Nasopharyngeal aspirates collected and transported under refrigerated conditions within 24 hours.
  • Isolation on selective and non-selective charcoal agar plates, with incubation for 3-4 days.
  • Confirmation using biochemical tests, B. pertussis antiserum agglutination, fimbrial serotyping, erythromycin susceptibility testing, and Pulsed Field Gel Electrophoresis (PFGE) for DNA fingerprinting.

Main Results:

  • Serotype 1,3 was the most prevalent among the Bordetella pertussis isolates.
  • A predominant pulsetype (PTA) accounted for 71.4% of the strains, with eight subclones (23.5%) and three unrelated pulsetypes also identified.
  • All examined Bordetella pertussis strains were susceptible to erythromycin; no resistant strains were detected.

Conclusions:

  • The study successfully defined favorable conditions for Bordetella pertussis isolation and characterization.
  • The findings indicate a dominant circulating strain (serotype 1,3, PTA) during the vaccine trial period.
  • The absence of erythromycin resistance in the studied strains is a significant finding for treatment and control strategies.

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