Variation in virulence between three representative Bordetella pertussis pertactin-negative clinical isolates

Area of Science:

• Bacteriology
• Immunology
• Vaccinology

Background:

• Pertussis (whooping cough) is caused by Bordetella pertussis.
• Acellular pertussis (aP) vaccines replaced whole-cell (wP) vaccines, but pertussis cases have increased.
• Pertactin-negative (PRN NEG) strains are increasingly prevalent globally.

Purpose of the Study:

• To identify a suitable PRN NEG Bordetella pertussis strain for challenge studies.
• To compare the virulence of PRN NEG strains against a PRN-positive (PRN POS) strain.

Main Methods:

• Baboons were challenged with a PRN POS strain (D420) or one of three PRN NEG strains.
• Colonization and virulence were assessed in challenged baboons.

Main Results:

• PRN NEG strains showed comparable colonization to D420.
• Virulence varied among the three PRN NEG strains.
• Two of the three PRN NEG strains exhibited reduced virulence compared to D420.

Conclusions:

• Some circulating PRN NEG Bordetella pertussis strains may be less virulent than PRN POS strains.
• Careful selection of PRN NEG strains is crucial for baboon and controlled human infection model (CHIM) studies.
• Maintaining pertactin (PRN) in aP vaccines may be beneficial due to potential differences in virulence.