High-resolution typing of Leptospira interrogans strains by multispacer sequence typing

Area of Science:

• Microbiology
• Epidemiology
• Genetics

Background:

• Leptospirosis, a global zoonotic disease caused by Leptospira, presents diagnostic challenges with current genotyping methods.
• Accurate identification of Leptospira serovars is crucial for effective epidemiological surveillance and control.

Purpose of the Study:

• To evaluate the efficacy of multispacer sequence typing (MST) for genotyping Leptospira interrogans strains.
• To compare the discriminatory power of MST with variable-number tandem-repeat (VNTR) typing for prevalent French serogroups.

Main Methods:

• Analysis of 33 reference strains of L. interrogans serogroups (Icterohaemorrhagiae, Australis, Canicola, Grippotyphosa) using both VNTR and MST.
• Construction of an MST database for defining MST profiles.
• Comparison of genotyping results and discriminatory power (Hunter-Gaston index) between MST and VNTR.

Main Results:

• MST profiles correlated well with VNTR results for all tested serogroups.
• MST provided higher resolution than VNTR for L. interrogans serovar Icterohaemorrhagiae (HGI: 0.94 vs. 0.68).
• MST enabled accurate identification of clinical isolates to the serovar or isolate level, especially for the Icterohaemorrhagiae serogroup.

Conclusions:

• MST is a simple, robust, and highly discriminatory method for genotyping L. interrogans.
• MST enhances epidemiological surveillance of circulating L. interrogans strains, particularly those of public health concern.
• The method facilitates precise identification of serovars, aiding in disease control strategies.