Mycobacterium tuberculosis mycolic acid Tuberculosis-attack the lungs communicable disease

1. MYCOBACTERIUM
TUBERCUlOSIS
Prepared by
K.RAMYA
II M.Sc., MICROBIOLOGY
Under guidence of
MRS.S.SELVAJEYANTHI
Asst.Professor
Department of Microbiology
Tiruppur kumaran college for
women,Tirupur.

2. MYCOBACTERIUM TUBERCULOSIS
Class : Actionobacteriya
Order: Mycobacteriales
Family: Mycobacteriaceace
Genus: Myobacterium
Species:M.tubercolesis
TAXONOMY

3. INTRODUCTION
• M.tuberculosis the known as the “tubercle bacillus”
was first described
24 March 1882 by Robert koch,who subsequently
received by Nobel prize in physiology or medicine
for this discovered in 1995;the bacterium is also
known as “kuch’s bacillus”
• Tuberculosis (TB) is a dangerous and highly
contagious bacterial disease caused by
Mycobacterium tuberculosis. It primarily affects the
lungs, but if left untreated, it might spread to
different parts of the body.

4. MORPHOLOGY
• Shape-long,slender,stright or slightly curved
rods with rounded end.
• Size-3×0.3 M
• Arrenged in groups or clumps,intracellular.
• Mycolic acid,waxes & lipids are present in
cell wall.
• Thay are acit fast,non sporing non capsulated
and motile.
• The high lipid content (approximately 60%) of
their cell wall makes mycobacteria acid fast
and hydrophobic.
• Neither gram + or gram _

5. ANTIGENIC STRUCTURE
• Two types of antigens are present to Mycobacteria.
1.Cell wall antigens
2.Cytoplasmic antigens
1.Cell wall(insoluble)antigens;
• The are inslouble antigens.
• Peptidoglycan layer : maintains shapes rigidity.
• Arbinogalactan layer : survival of M.tuberculosis with in macrophages.
• Mycolic acid layer : which is most important layers on the cell wall.
Acid fastness and reduces the entry of most antibiotics.
• Proteins(e.g;transport proteins): found through out various layers.

6. • Plasma membrane: helps in attachment to host cell and is also a target
antigen used for diagnosis.

7. 2.Cytoplasmic (soluble) antigens;
• These include antigen5,antigen6,antigen60,
-used in serodiagnosis of tuberculosis

8. TYPES OF TUBERCULOSIS
There are two different types of tuberculosis:
• Pulmonary Tuberculosis.
• Extrapulmonary Tuberculosis.
1.Pulmonary Tuberculosis;
• It is an endemic infection affecting the lungs. It is further classified into:
• Primary Tuberculosis Pneumonia: Associated symptoms include coughing
and high fever. It can also arise in patients with HIV/AIDS.
• Miliary Tuberculosis: This form of TB is named so because of a distinctive
pattern seen on a chest radiograph, where many small spots are distributed
throughout the lung fields, bearing an appearance similar to millet seeds. The
infection can eventually spread to the extrapulmonary organs, such as the
spleen, liver, and kidneys.

10. 2.Extrapulmonary Tuberculosis;
• It is usually seen in immunocompromised patients. There are several
types:
Tuberculosis meningitis
Osteal tubeculosis
Lymphnode disease
Renal tubeculosis
Adrenal tuberculosis

12. BIOCHEMICAL PROPERTIES
• A number of biochemical test tubes have been carried out a
differentiate amoung various Mycobacteria species.
Nitrate reduction(+), Niacin(+),Urease test(+),catalase test(+),
ion uptake(+),Nacl(-)

13. CULTURE CHARACTERISTICS
• They are obligate aerobes.
• The bacili have slow growth,with a genaration time of 14-15 hours in vitro.
• The colonies may be appear after 2 weeks and may take upto 8 weeks.
• The optimum temperature is 37°c,optimum PH is 6.4,7.0 .
• The colonies are dry,rough&cream coloured cannot be easily emulsified.
• In Liquid media like Dubo’s medium they produce uniform growth.
• Commonly used medium is lowenstain jense medium,used staining ziehl
neelson staining.
• Culture are incubated upto 6 weeks.

14. LOWENSTAIN JENSE MEDIUM
• M. tuberculosis requires aerobic conditions and a protein-enriched
medium for culture. Lowenstein–Jensen (LJ) slopes are the main solid
media used to culture Mycobacteria. It contains inspissated eggs,
malachite green, and glycerol (or pyruvate). LJ medium containing
glycerol favors the growth of M. tuberculosis while LJ medium without
glycerol but containing pyruvate encourages the growth of M. bovis.

15. ZIEHL – NEELSEN STAINING
• Ziehl-Neelsen (ZN) method of acid-fast staining technique is used to
stain Mycobacterium species including M. tuberculosis, M. ulcerans, and M.
leprae and nontuberculous mycobacteria (NTM). Detection of acid-fast
bacilli (AFB) in stained and acid-washed smears examined microscopically
may provide the initial bacteriologic evidence of the presence of
mycobacteria in a clinical specimen. Smear microscopy is the quickest and
easiest procedure that can be performed.
• The cell wall of Mycobacteria contains high concentrations of lipid making
them waxy, hydrophobic, and impermeable to routine stains such as the
Gram Stain. They are also resistant to acid and alcohol and are described as
acid-fast bacilli (AFB) or acid alcohol fast bacilli (AAFB).

17. PATHOGENESIS
• No exotoxin,endotoxin.
• Individuals with a weak immune system are at increased risk.
• Metabolic diseases such as diabetes can also increase the risk of
contracting TB.
• Tuberculosis is a contagious airborne disease, which can be acquired
from close contact with an infected person.
• Mycobacterium Tuberculosis is one of the leading causes of this
dreadful infectious disease.
• Mode of infection is by direct inhalation of droplet nuclei formed
through coughing,sneezing,speaking by an open case of tuberclosis.

19. SYMPTOMS OF TUBERCULOSIS
• TB bacteria or Mycobacterium tuberculosis multiply once it gets into
the lungs. It can cause severe symptoms such as:
SYMPTOMS
1.Coughing
up blood
and mucus
from deep
inside the
lungs
2.Weakness
at night
3.Pain in the
chest

21. LABORATORY DIAGNOSIS
• Apart from all the physical tests, other tests are available to diagnose the
presence the infectious bacteria.
SPECIMEN
Sputum
Blood
Urine
Skin test
Chest-x-rays

22. sputum tests
• Rapid sputum tests are used to diagnose
tuberculosis (TB) when other tests show that
a person probably has TB. Rapid sputum
tests are also called nucleic acid
amplification tests (NAATs).
• One of the best ways to diagnose TB is
through a sputum culture. A sample of
sputum is added to a substance that promotes
the growth of bacteria.If TB bacteria grow,
then the person has tuberculosis. The test
also can show if a lung infection is caused by
some other kind of bacteria. A sputum
culture can take 1 to 8 weeks to provide
results.

24. BLOOD TESTS
• Blood tests for TB, also called serological tests, are tests that are
carried out on blood samples. Serological or serodiagnostic tests
for TB means diagnosing TB through looking at a blood sample,
and specifically looking for antibodies in the blood sample. But
you cannot diagnose TB disease this way.
• Testing for TB by detecting antibodies in the blood is extremely
difficult. People can have antibody responses suggesting that they
have active TB even when they do not. Antibodies may also
develop against other organisms that again could wrongly indicate
that they have active TB

26. SKIN TESTS
• It is the most common type of
test. In this procedure, a small
sample of Tuberculin – a
purified protein is injected
under the patient’s skin. If the
skin around the site of the
injection gets swollen more than
five millimetres, then it is a
clear indication of TB infection.

28. X PERT MTB/ RIF ASSAY
• GeneXpert MTB/RIF
assay is a nucleic acid
amplification test which
simultaneously detects
DNA of Mycobacterium
tuberculosis complex
(MTBC) and resistance
to rifampin (RIF) (i.e.
mutation of the rpoB
gene) in less than 2 hours

30. TREATMENTS
• Drug treatment is one of the most efficient ways to treat this infectious
disease. For patients with Latent TB infections, doctors generally
prescribe an antibiotic called isoniazid for preventing the latent
infection from becoming active.
• Active TB Diseases will be deadly if left untreated. The procedure
involved is taking a combination of ethambutol, INH, priftin and for a
term of three months, followed by a mix of INH and pyrazinamide for
12 months.

31. Anti-TB-derugs
First line
1.Lsoniazid
2.Pyrazinaide
3.Streptomycn
4.Rfampicn
Newer drugs
1.Ciprofloxacin
2.Ofloxacin
3.Clarithromycine
4.Azitromycin
Second line
1.Ethionamide
2.Cycloserine
3.Kanamycin
4.Amikacin

34. PREVENTIONS