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Special Seminar - Jordan Romeyer Dherbey: Evolutionary history of M. tuberculosis

  • Date: Oct 22, 2018
  • Time: 10:00 - 11:00
  • Speaker: Jordan Romeyer Dherbey, France
  • Location: MPI Plön
  • Room: Lecture hall
  • Host: Frederic Bertels

Abstract

Mycobacterium tuberculosis, the causative agent of human tuberculosis, is one of the most widely spread human pathogens. It typically affects the lungs and creates lesions in patients in order to be efficiently spread to new individuals through a cough (droplets and aerosols). Over the past twenty years, tuberculosis has undergone an important resurgence and now is a worldwide issue for human health. Tuberculosis affects approximately 10 million people each year and is one of the top ten causes of death worldwide (the first linked to infections by a unique pathogenic agent). Despite a decrease of mortality around 3% each year, the spread of M. tuberculosis drug-resistant strains is a serious threat. To stop the spread of such bacteria, it is important to understand its success and the evolutionary mechanisms that let it progressively adapt to new hosts.

Recent genome-based studies have found evidence that the Mycobacterium tuberculosis Complex (MTBC) likely emerged from a pool of recombinogenic mycobacterial strains with smooth colony morphology (Smooth Tubercle Bacilli - STB). The STB, named Mycobacterium canettii was first isolated in 1969 at Djibouti by Dr. Georges Canetti, from patients who developed tuberculosis-like infections. Analyses of genome sequences of multiple M. canettii strains have allowed an estimation of the ancestral gene pool of tubercle bacilli. Notably, M. canettii strains show highly recombinogenic genomes, which is not the case for M. tuberculosis genomes, suggesting that horizontal gene transfer has played an important role in the evolution of tuberculosis-causing mycobacteria.

 
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