Identification of pathogenic Leptospira species and serovars in New Zealand using metabarcoding

Area of Science:

• Microbiology
• Genetics
• Epidemiology

Background:

• Leptospirosis is a significant zoonotic disease globally, caused by diverse Leptospira species.
• Classical diagnostic methods struggle with Leptospira diversity, leading to increased reliance on molecular tools.
• In New Zealand, unidentified Leptospira cases highlight the need for improved diagnostic specificity.

Purpose of the Study:

• To identify a molecular marker for discriminating New Zealand-endemic Leptospira species and serovars.
• To evaluate the utility of the glmU gene as a molecular barcode using Oxford Nanopore Technology (ONT).
• To investigate the presence of previously unreported Leptospira genomospecies in New Zealand.

Main Methods:

• Genomic data analysis to identify a suitable discriminatory gene region (glmU).
• Application of the glmU locus for Leptospira identification in culture and culture-independent samples.
• Utilisation of Oxford Nanopore Technology (ONT) MinION for sequencing and barcoding.

Main Results:

• The glmU gene region effectively discriminates between Leptospira species and serovars.
• ONT sequencing enabled species identification in mixed environmental cultures.
• Potential presence of novel Leptospira genomospecies, including L. borgpetersenii and L. mayottensis, detected in New Zealand.

Conclusions:

• The glmU gene serves as a flexible molecular barcode for Leptospira diagnostics in humans, animals, and environmental samples.
• ONT sequencing offers potential for rapid Leptospira identification, despite current limitations in strain-level accuracy.
• This study expands the known Leptospira diversity in New Zealand, with implications for public and animal health surveillance.