Assembly and Comparison of Ca. Neoehrlichia mikurensis Genomes

Area of Science:

• Microbiology
• Genomics
• Veterinary Medicine

Background:

• Candidatus Neoehrlichia mikurensis (CNM) is prevalent in Ixodes ricinus ticks and linked to human illness.
• Limited diagnostic tools and biological knowledge hinder CNM research and clinical management.
• Culturing CNM is challenging, complicating disease diagnosis and study.

Purpose of the Study:

• To present the first complete genomes of CNM directly from wildlife reservoir hosts.
• To establish a practical method for obtaining pathogen genomes without relying on clinical samples or bacterial cultures.
• To identify potential targets for developing new diagnostic methods for CNM.

Main Methods:

• Whole-genome sequencing using both long-read and short-read technologies.
• Direct DNA extraction from wildlife reservoir host tissues.
• Bioinformatic analysis of obtained genomic data.

Main Results:

• Successfully generated complete CNM genomes from host tissues, bypassing culture requirements.
• The derived genomes possess larger chromosomes compared to previously sequenced CNM genomes.
• The methodology provides a viable alternative for studying emerging infectious agents.

Conclusions:

• Direct genome sequencing from host tissues is an effective strategy for characterizing difficult-to-culture pathogens like CNM.
• The larger genomes may offer novel targets for future diagnostic test development.
• This approach can be applied to other tick-borne pathogens, advancing their study and diagnosis.