Special Seminar - Jordan Romeyer Dherbey: Evolutionary history of M. tuberculosis
Oct 22, 2018
10:00 - 11:00
Jordan Romeyer Dherbey, France
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