Thursday 25 September 2014

Bar code devised for bacteria that causes tuberculosis

Scientists will be able to easily identify different types of tuberculosis (TB) by using a new genetic barcode. To help identify the different origins and map how tuberculosis moves around the world, spreading from person to person through the air, the research team studied over 90,000 genetic mutations.

Mycobacterium tuberculosis is a pathogenic bacterial species in the family Mycobacteriaceae and the causative agent of most cases of tuberculosis. M. tuberculosis is genetically diverse, which results in significant phenotypic differences between clinical isolates. Different strains of M. tuberculosis are associated with different geographic regions. However, phenotypic studies suggest the strain variation never has implications for the development of new diagnostics and vaccines. Microevolutionary variation does affect the relative fitness and transmission dynamics of antibiotic-resistant strains.

Mycobacterium outbreaks are often caused by hypervirulent strains of M. tuberculosis. In laboratory experiments, these clinical isolates elicit unusual immunopathology, and may be either hyperinflammatory or hypoinflammatory. The majority of hypervirulent mutants have deletions in their cell wall-modifying enzymes or regulators that respond to environmental stimuli. The mechanisms that enable M. tuberculosis to mask its full pathogenic potential, inducing a granuloma that provides a protective niche, enable the bacilli to sustain a long-term, persistent infection.

According to the study the researchers found that just 62 mutations are needed to code the global family of strains.

For further details see:

Francesc Coll, Ruth McNerney, José Afonso Guerra-Assunção, Judith R. Glynn, João Perdigão, Miguel Viveiros, Isabel Portugal, Arnab Pain, Nigel Martin, Taane G. Clark. A robust SNP barcode for typing Mycobacterium tuberculosis complex strains. Nature Communications, 2014; 5: 4812 DOI: 10.1038/ncomms5812

Posted by Tim Sandle

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