4. MORPHOLOGY
They are slender, straight or slightly curved rods
with round end.
They are weakly gram positive and size measures
from 1-4 X 0.2-0.8 mu m
They are non-motile, non-sporing and non-
capsulated.
Occurs as singles or in the form of chains.
5. CULTURAL CHARACTERISTICS
They are aerobes that grows slowly.
The optimum tempareture is 37 degree C (30-40) and pH
7.0 (6.4-7.0)
Growth will be maximum in media which contains serum,
glycerol, egg, meat extracts and potato extracts
Lowenstein-jenson medium is most widely used for the
isolation of this organism.
6. LIQUID MEDIA (DUBO’S MEDIUM)
The organism either forms surface pellicle
that extends along the side of tube or
grows as floccules throughout the medium.
7. SOLID MEDIA
Most solid culture media contain egg (LJ
medium, petragini or dorest medium), serum
(loeffler’s serum slope) or potato(pawlowsky’s
medium).
Egg based medium especially LJ medium have
been widely used for the primary isolation of
organism from clinical specimen.
8. CHICK EMBRYO AND TISSUE CULTURE
MEDIUM
The abundant growth of bacilli will taking
place in the Chick embryo and tissue
culture medium
9. PATHOGENESIS
Infection occurs when a person inhales droplet
nuclei containing tubercle bacilli that reach the
alveoli of the lungs.
These tubercle bacilli are ingested by alveolar
macrophages; the majority of these bacilli are
destroyed or inhibited. A small number may
multiply intracellularly and are released when the
macrophages die.
10. these bacilli may spread by way of lymphatic
channels or through the bloodstream to more
distant tissues and organs (including areas of
the body in which TB disease is most likely to
develop: regional lymph nodes, apex of the
lung, kidneys, brain, and bone).
11. In some people, the tubercle bacilli overcome
the immune system and multiply, resulting in
progression of TB disease.
Persons who have TB disease are usually
infectious and may spread the bacteria to
other people.
Body fluid or tissue from the disease site
should be collected for AFB smear and
culture. Positive culture for M. tuberculosis
confirms the diagnosis of TB disease.
12. TYPES OF TB
PRIMARY TUBERCULOSIS
SECONDARY TUBERCULOSIS
13. PRIMARY TUBERCULOSIS
Primary pulmonary tuberculosis is seen in
patients not previously exposed
toMycobacterium tuberculosis.
This may occur in any organ such as lungs,
tonsils, intestine or skin
Among children the common site is lungs.
14. The inhaled bacilli are engulfed by alveolar
macrophages in which they multiply to form
initial lesions called GHON FOCI.
Most frequently it occur in the lower lobe or
lower part of the upper lobe.
From here some bacilli are transported to
hilar lymph node and causing
lymphadenopathy.
15.
16. The ghon foci together with the enlarged
hilar lymph node forms primary infecton.
In most cases the primary infection is
asymptomatic
Occassionally the primary infection may
spread through lymph nodes and causes
bone & join tuberculosis, renal tuberculosis,
meningeal tuberculosis, endometrial
tuberculosis and testicular tuberculosis.
17. SECONDARY TUBERCULOSIS
This type of infection is mainly caused by reactivation of
primary lesions or by bacilli that are inhaled or ingested
from the environment.
It is otherwise known as post primary tuberculosis or adult
tuberculosis.
It mostly involves lungs and lesions are produced in the
apical region ( apex) of the lungs and can be transmitted to
kidney, meninges, bones and other organs.
18. Formation of granuloma occurs and the necrotic
elements of the reaction cause destruction of
the tissues and large areas of caseation,
termed as tuberculomas (A tuberculoma is a
clinical manifestation of tuberculosis which
conglomerates tubercles into a firm lump, and
so can mimic cancer tumors of many types in
medical imaging studies)
19. The activated macrophages secrete the
enzyme protease that causes softening
and liquefaction of necrosis.
the necrosis is entered to the bronchus
from the lungs and leaving a cavity (cavity
TBC)
20. The necrosis then enters to the blood
vessels and spreading the bacilli through
out the body.
21. Signs and symptoms of active TB include:
Coughing that lasts three or more weeks
Coughing up blood
Chest pain, or pain with breathing or coughing
Unintentional weight loss
Fatigue
Fever
Night sweats
Chills
Loss of appetite
22. LABORATORY DIAGNOSIS
DIRECT METHODS
It includes
1. Hematological investigations: which shows
an increase in the leucocytes, monocytes,
neutrophil and lymphocytes.
24. MICROSCOPY
The specimen used are sputum, laryngeal
swab, pleuaral fluid, peritoneal fluid, CSF,
pus, urine, gastric lavage and feces.
In microscopy after acid fast staining the
bacilli will appear in pink color as rods in a
blue background.
25. CULTURE
1. PETROFF’S METHOD
In this method, 3-5 ml of sputum was homogenized
for 15 min in a shaker using an equal volume of 4%
NaOH.
After centrifugation at 3,000 rpm for 15 min, the
deposit was neutralized with 20 ml of sterile
distilled water.
* rpm- revolutions per minute
26. The samples were again centrifuged. From
the sediment, LJ medium (Lowenstein-Jensen
Medium) was inoculated and smear was made.
The culture slants were incubated at 37°C.
Absence of growth at the end of 8 th weeks
was regarded as negative culture.
27. 2. HOMOGENIZATION TEST
In this method, specimen is treated with
dilute acids like H2SO4,Hcl,oxalic acid.
The acid cleared by repeated washing with
sterile normal saline.
28. 3. FLOCCULATION METHOD
In this method specimen is treated with
digester containing NaOH and potash
alum.it is neutralized with acid
Floccules (small clump) will appear which
are sedimented by centrifugation.
29. 4. JUNGMANN’S METHOD
In this test H2O2 and FeSO4 are used.
A bulky deposit is formed in positive
cases.
30. 5. N-ACETYL-1-CYSTEINE WITH NAOH
It is the effective and rapid culture
method
The concentrated material is inoculated
into two bottle of LJ medium and
incubated at 37degree C up to 12 weeks
(avg 4-8wks)
31. Cultures are examined first after 4 days,
then weekly till 8 weeks to find out the
growth of bacteria.
The bacilli grow in 2-8 wks
If there is no growth occurs till the 8-12
week the result is negative
32. BIOCHEMICAL TESTS
Niacin test : positive
Aryl sulphatase test : negative
Catalase test : positive
Neutral red test : positive
Nitrate reduction test : positive
33. ANIMAL INOCULATION TEST
Two healthy guinea pigs are selected for
the study which was not infected with any
type of tuberculosis.
The weight was noted
34. 0.5ml of the materialis injected intra
muscularlly into the thigh of both animals.
One animal is killed after 4 weeks and if
no evidance of TBC is noticed in autopsy,
then the other animal is killed in the 8th
week.
35. If the pig is infected with TB ,the autopsy
findings will be
1. Caseous lesion in the site of inoculation
2. Enlarged caseous draining lymph nodes
3. Tubercles in lung and peritoneum
4. Enlargment of spleen with areas of
necrosis.
37. TINE TEST
This test uses a tiny spiked instrument to
inject a small amount of the tuberculosis
dead protein material (antigen) just under
your skin.
This is most commonly done on the arm.
Usually, the area is marked with an ink pen.
That way it can be checked for any redness
and swelling. It is usually checked in 2 to 3
days.
38. NORMAL FINDINGS
If you have a negative test result,
the area may be a little red, but will not be
swollen and firm like a mosquito bite. This
means you have not been exposed to the
bacteria that cause tuberculosis.
39. ABNORMAL RESULTS
If you have been exposed to tuberculosis,
the area will become red and swell like a
mosquito bit in 48 to 72 hours. This is
considered a positive test result.
It means your body's immune system
detected the substance injected under
your skin.
40. HEAF TEST
This test is done with multiple puncture
apparatus called heaf gun with 6 needles
that prick 1-2 mm deep in the skin.
A drop of PPD is prepared on inoculation is
administered in the area of the skin then
the needle is released.
41.
42. INTERPRETATION OF HEAF TEST
Test is normally read at 7 days but can be
read between 3-10 days.
45. MANTOUX TEST
This test is also known as mantoux
screening test or tuberculin sensitive test
or PPD test.
This test is standardized and using world
widely to diagnose TB
51. ELISA (ENZYME LINKED
IMMUNOSORBENT ASSAY)
An enzyme-linked immunosorbent assay, also called
ELISA or EIA, is a test that detects and
measures antibodies in your blood.
This test can be used to determine if you have
antibodies related to certain infectious conditions.
Antibodies are proteins that your body produces
in response to harmful substances called antigens.
52.
53. TREATMENT
Rifampicin and isoniazide is the common
antibiotics used.
Ethambutol, ethionamide,and thiacetazone
are other drug used for the treatment of
TB.
