A novel multilocus variable-number tandem repeat analysis for Bordetella parapertussis

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Molecular Epidemiology

Background:

• Human-adapted *Bordetella parapertussis* causes whooping cough.
• Existing genotyping methods lack sufficient discriminatory power for *B. parapertussis*.
• Accurate genotyping is crucial for epidemiological surveillance and outbreak investigation.

Purpose of the Study:

• To develop a novel multilocus variable-number tandem repeat analysis (MLVA) for human-adapted *B. parapertussis*.
• To assess the discriminatory power of the developed MLVA method.

Main Methods:

• Selection of four highly polymorphic VNTR loci in the *B. parapertussis* genome.
• Development of a multiplex PCR assay for VNTR amplification.
• MLVA typing of 53 *B. parapertussis* strains (3 reference, 50 isolates) based on repeat copy numbers.

Main Results:

• The MLVA method successfully genotyped 53 *B. parapertussis* strains into 25 distinct MLVA types.
• A high Simpson diversity index of 0.91 indicated significant discriminatory power.
• Isolates from different geographic locations showed varying patterns, with Australian isolates clustering into a single type.

Conclusions:

• The developed MLVA method offers high discriminatory power for genotyping human *B. parapertussis*.
• This novel genotyping system is a valuable tool for epidemiological surveillance.
• The MLVA method shows promise for investigating *B. parapertussis* outbreaks.