Revisiting the evolution of Mycobacterium bovis

Area of Science:

• Veterinary Microbiology
• Genomics
• Infectious Diseases

Background:

• Mycobacterium tuberculosis primarily infects humans, while M. bovis and related organisms infect a wide range of animals, notably cattle.
• Limited genomic characterization exists for M. bovis isolates from non-bovine hosts.

Purpose of the Study:

• To investigate if variable genomic content in M. bovis/M. bovis-like isolates correlates with distinct host distributions.
• To explore the genomic diversity within M. bovis and related species.

Main Methods:

• Genomic DNA content analysis of M. bovis/M. bovis-like isolates from various hosts using Affymetrix GeneChip.
• Identification of large sequence polymorphisms and deleted regions.

Main Results:

• Large sequence polymorphisms clearly distinguished M. bovis isolates.
• Genomic profiles showed structured variability, with some profiles linked to geography and others to host type.
• Distinct Mycobacterium tuberculosis complex (MTC) lineages appear to differentially infect various mammal species, contrary to the broad host capacity assumption for M. bovis.

Conclusions:

• Genomic stratification of M. bovis genotypes provides a framework for understanding host-pathogen interactions.
• This phylogenetic stratification can guide future genetic and phenotypic studies of the MTC in diverse mammalian hosts.