Download Mycobacterium tuberculosis

Mycobacterium tuberculosis Characteristics
 Mycobacterium tuberculosis is a
non-motile, acid-fast, obligate aerobe
bacterium that resists decolorization
with acidified organic solvents
Considered hydrophobic due to the
high lipid content in the cell wall
 It is not considered gram positive
nor gram negative, but instead is
classified as acid-fast
 M. tuberculosis is manifested more
often in HIV positive patients due to a
weakened immune system
 High resistance to drug therapy
http://www.turbosquid.com/3d-models/3d-mycobacterium-tuberculosis-model/683105
 Contagious for several weeks after
drug therapy is initiated
A. Ryan F2013
Modified by DYH
M. tuberculosis Virulence

M. tuberculosis does not have the classical
virulence factors

Lipoamide dehydrogenase (Lpd) - helps
the bacterium resist host-reactive nitrogen
intermediates

Antigen 85 complex: group of
secretedproteins that bind fibronectin;
may help in protecting the bacterium from
the immune system

Slow generation time: immune system
may not readily recognize the bacterium
and therefore not be able to kill it

High lipid concentration of cell wall:
enables the bacterium to be resistant to
many antimicrobial agents, acidic and
alkaline compounds, and osmotic lysis
http://medicineworld.org/images/blogs/11-2007/mycobacterium-tuberculosis-299290.jpg

Cord factor: known to be toxic to humans
and other mammalian cells
A. Ryan F2013
Modified by DYH