Objective : Describe the morphology and structure of mycobacterial tuberculosis ? What are the tests required for mycobacterial infection : Mantoux skin test Sputum examination using Ziehl-Neelsen staining Sputum culture using lowenstein-jensen media Discuss the clinical features and transmission of mycobacterial tuberculosis. What are the pathological changes in mycobacterium tuberculosis? How to control mycobacterial infection in the environment and vaccine available? done by : asem shadid , college of medicine .

1. A S E M S H A D I D
PBL 2 –POD 1

2. OBJECTIVES :
• Describe the morphology and structure of mycobacterial
tuberculosis ?
• What are the tests required for mycobacterial infection :
• Mantoux skin test
• Sputum examination using Ziehl-Neelsen staining
• Sputum culture using lowenstien-jensen media
• Discuss the clinical features and transmission of
mycobacterial tuberculosis.
• What are the pathological changes in mycobacterium
tuberculosis?
• How to control mycobacterial infection in the environment
and vaccine available?

3. DESCRIBE THE MORPHOLOGY
AND STRUCTURE OF
MYCOBACTERIUM
TUBERCULOSIS ?

4. • Mycobacterium is a genus of Actinobacteria , given its own family,
the Mycobacteriaceae.
• ( Actinobacteria are a group of Gram-positive bacteria )
• The genus includes pathogens known to cause serious diseases in
mammals, including tuberculosis (Mycobacterium tuberculosis) .
• Mycobacteria are Gram-resistant (waxy cell walls rich in lipid), non-
motile.
• Mycobacteria are aerobic ( use o2 ) and nonmotile bacteria , that
are characteristically acid-alcohol-fast.
• Acid-fastness is a physical property of certain bacteria
• Acid-fast organisms are difficult to characterize using standard
microbiological techniques (e.g. Gram stain )

5. MYCOBACTERIA ASSOCIATED WITH HUMAN
DISEASE
Mycobacterium Environmental contaminant Reservoir
M tuberculosis No Human
M bovis No Human, cattle
M leprae No Humn
M kansasii Rarely Water, cattle
M marinum Rarely Fish, water
M scrofulaceum Possibly Soil, water
M avium
intracellulare
Possibly Soil, water, birds
M ulcerans No Unknown
M fortuitum Yes Soil, water, animals
M chelonae Yes Soil, water, animals

6. Mycobacterium tuberculosis
Mycobacterium tuberculosis is
a pathogenic bacterial
species in the family
Mycobacteriaceae and the
causative agent of most
cases of tuberculosis.
Schematic diagram of Mycobacterial cell
wall.
1. outer lipids
2. mycolic acid
3. polysaccharides (arabinogalactan)
4. peptidoglycan
5. plasma membrane
6. lipoarabinomannan (LAM)
7. phosphatidylinositol mannoside
8. cell wall skeleton

7. What are the tests required for
mycobacterial infection :

8. • The Mantoux test or Mendel-Mantoux test Also known as: Purified
Protein Derivative; PPD; Mantoux , is a screening tool for tuberculosis
(TB) .
What does the test result mean?
A positive result will form a red and swollen circle at the
site of the injection.
a positive tuberculin skin test, an immune reaction to a
small quantity of tuberculosis antigens
A negative result for either test means that it is likely
that the person tested does not have a TB infection.
The Mantoux skin test consists of an
intradermal injection of one-tenth of a
milliliter (ml) of PPD tuberculin.

9. The Ziehl–Neelsen stain, also known as the acid-fast stain AFB Acid-Fast
Bacillus .
t is a special bacteriological stain used to identify acid-fast organisms, mainly
Mycobacteria. Mycobacterium tuberculosis is the most important of this
group because it is responsible for tuberculosis (TB) ‫السل‬ .
• Acid-fastness is a physical property of certain bacteria
• Acid-fast organisms are difficult to characterize using standard
microbiological techniques (e.g. Gram stain )
A negative AFB smear may mean that
no infection is present, that symptoms
are caused by something other than
mycobacteria
What does the test result mean?
Positive AFB smears indicate a
probable mycobacterial infection.
Mycobacterium tuberculosis (stained red) in
tissue (blue).

10. • LJ medium is A growth medium called also The Löwenstein–Jensen
medium.
• A growth medium or culture medium is a liquid or gel designed to
support the growth of microorganisms There are different types of media
for growing different types of cells.
• LJ medium specially used for culture of Mycobacterium, mostly the
Mycobacterium tuberculosis.
• When grown on LJ medium, M. tuberculosis appears as brown
Löwenstein-Jensen medium used for
growing M. tuberculosis in a McCartney
bottle.
Uses
For diagnosis of Mycobacterial infections
For testing antibiotic aptly of isolates
For differentiating different species of mycobacterium

11. Discuss the clinical features and
transmission of mycobacterial
tuberculosis.

12. • TB is an airborne - ‫جوا‬ ‫محمول‬- disease caused by the bacterium
Mycobacterium tuberculosis (M. tuberculosis) .
• Tuberculosis kills 3,000,000 people in the world every year, more than AIDS
• How is TB diagnosed?
Symptoms of tuberculosis include:
1. Fever
2. Night-time sweating
3. Loss of weight
4. Persistent cough
5. Constant tiredness
6. Loss of appetite
• Diagnosis of tuberculosis is made by :
1. a positive tuberculin skin test
2. It can be confirmed by X rays of the chest
3. microscopic examination of sputum
4. Detection of significant numbers of acid-fast bacilli (using the Ziehl-Neelsen stain)
5. laboratory culture of the bacterium

13. Transmission of TB :
M. tuberculosis is carried in airborne particles, called droplet nuclei, of 1– 5
microns in diameter.
Infectious droplet nuclei are generated when persons who have pulmonary
or laryngeal TB disease cough, sneeze, shout, or sing. It can also occur
through the gastrointestinal tract
Depending on the environment, these tiny particles can remain in the air for
several hours.
M. tuberculosis is transmitted through the air, not by surface contact.
• Young children with pulmonary
and laryngeal TB disease are
less likely than adults to be
infectious.

14. What are the pathological
changes in mycobacterium
tuberculosis?

15. Droplet nuclei
containing tubercle
bacilli are inhaled,
enter the lungs, and
travel to the alveoli.
Tubercle bacilli multiply
in the alveoli.
A small number of tubercle bacilli enter
the bloodstream and spread throughout
the body. The tubercle bacilli may reach
any part of the body, including areas
where TB disease is more likely to
develop (such as the brain, larynx, lymph
node, lung, spine, bone, or kidney).

16. Within 2 to 8 weeks, special immune cells called macrophages ingest and
surround the tubercle bacilli. The cells form a barrier shell
called a granuloma . is an inflammation found in many diseases. It is a
collection of immune cells known as macrophages.
If the immune system
cannot keep the
tubercle bacilli under
control, the bacilli
begin to multiply rapidly
(TB disease).

17. How to control mycobacterial
infection in the environment
and vaccine available?

18. VACCINATION SCHEDULE IN SAUDI ARABIA?