Multispacer Sequence Typing for Mycobacterium bovis Genotyping.

Area of Science:

• Veterinary Microbiology
• Genetics and Genomics
• Epidemiology

Background:

• Bovine tuberculosis, caused by Mycobacterium bovis, necessitates robust molecular typing for epidemiological control.
• Existing typing methods for M. bovis have limitations, highlighting the need for alternative approaches.
• Multispacer sequence typing (MST) has been successfully applied to M. tuberculosis but not yet evaluated for M. bovis.

Purpose of the Study:

• To evaluate the efficacy and discriminatory power of Multispacer Sequence Typing (MST) for molecular characterization of Mycobacterium bovis isolates.
• To assess MST as a potential alternative genotyping method for M. bovis, comparing its performance with established techniques.

Main Methods:

• Typing of 58 M. bovis strains from Brazilian cattle herds and four standard samples using MST.
• Analysis of fourteen intergenic regions, identifying single nucleotide mutations, insertions, deletions, and tandem repeats.
• Selection of seven informative loci, calculation of the Hunter-Gaston Discriminatory Index (HGDI), and phylogenetic analysis using eBURST software.

Main Results:

• Identification of 28 distinct sequence types (STs) among the M. bovis isolates.
• Achieved a high discriminatory index (HGDI) of 92.9%, demonstrating MST's effectiveness in differentiating strains.
• Phylogeographic analysis revealed clonal complexes, correlating MST data with spoligotyping results.

Conclusions:

• Multispacer Sequence Typing (MST) is a viable and highly discriminatory alternative method for genotyping Mycobacterium bovis.
• The sequencing-based nature of MST and the availability of public sequence data facilitate global application and further research.
• This study provides the first evaluation of MST for M. bovis, offering a valuable tool for understanding bovine tuberculosis epidemiology.