Multispacer typing technique for sequence-based typing of Bartonella quintana

Area of Science:

• Microbiology
• Genetics
• Infectious Diseases

Background:

• Bartonella quintana causes various human diseases, including trench fever and endocarditis.
• Genome sequencing of Bartonella quintana enabled the development of novel typing methods.
• Understanding Bartonella quintana's genetic diversity is crucial for epidemiological studies.

Purpose of the Study:

• To develop and validate a genome-wide, sequence-based typing method for Bartonella quintana.
• To assess the genetic diversity and genomic stability of Bartonella quintana isolates.
• To identify new Bartonella quintana genotypes in natural reservoirs.

Main Methods:

• Development of a multispacer typing (MST) method targeting polymorphic regions in the Bartonella quintana genome.
• Sequencing of 34 spacers in a large collection of Bartonella quintana isolates.
• Comparison of MST results with pulsed-field gel electrophoresis (PFGE) profiles and analysis of genomic rearrangements.

Main Results:

• Six polymorphic spacers were identified, enabling the characterization of four distinct Bartonella quintana genotypes.
• MST results showed low sequence heterogeneity, suggesting recent emergence as a pathogen.
• Pulsed-field gel electrophoresis (PFGE) indicated high genomic instability, rendering it unreliable for epidemiology.
• A fifth Bartonella quintana genotype was identified in DNA from a human body louse.

Conclusions:

• Multispacer typing (MST) is a reliable and discriminatory method for Bartonella quintana genotyping.
• Bartonella quintana exhibits low genetic diversity but high genomic instability.
• The identification of a new genotype in body lice highlights potential reservoirs and transmission routes.