Mycobacterium tuberculosis is the bacteria that causes tuberculosis. It is an aerobic bacteria that grows best in oxygen-rich tissues like the lungs. It has a complex cell wall containing mycolic acids that make it acid-fast and resistant to acids and alkalis. M. tuberculosis infects macrophages as a facultative intracellular pathogen and has a morphology of being slender, straight or slightly curved rods around 3 by 0.3 micrometers in size.

1. Mycobacterium Tuberculosis

2. INTRODUCTION:
 Mycobacterium tuberculosis is a species of Pathogenic
Bacteria in the family Mycobacteriaceae and the causative
agent of Tuberculosis. First discovered in 1882 by Robert Koch .
 Mycobacteria is an obligate aerobe growing most successfully
in tissues with a high oxygen content.(the upper lobe of the
lung and the kidney).
 Its cell wall contains several complex lipids ( long-chain fatty
acids called mycolic acids).

3.  It is relatively resistant to acids and alkalis. NaOH is used
to concentrate clinical specimens; it destroys unwanted
bacteria, human cells, and mucus but not the organism.
They are Facultative intracellular pathogens usually
infecting mononuclear phagocytes (e.g. macrophages).

4. MORPHOLOGY:
 SHAPE - long, slender, straight or slightly curved
rod.
 SIZE - 3 x 0.3 µm

5.  Intracellular.
 Mycolic acid, waxes & lipids are present in cell wall
 The high lipid content (approximately 60%) of
their cell wall makes mycobacteria acid-fast and
hydrophobic.
 Because the cells are hydrophobic and tend to
clump together, they are impermeable to the usual
stains, e.g. Gram's stain
 Neither gram-positive nor gram-negative.