SlideShare a Scribd company logo
1 of 11
Mycobacterium tuberculosis
 Slender rods that sometimes show branching
filamentous forms resembling fungal mycelium.
 In liquid cultures they form a mold-like pellicle~ hence
the name ‘mycobacterium’ = Fungus like bacteria.
 They are acid-fast, aerobic, non-motile, non-capsulated
and non-sporing, obligate parasites, opportunistic
pathogens and saprophytes.
 Robert Koch in 1882, isolated the mammalian strain and
proved its causative role in Tuberculosis.
 Mycobacterium has many bacilli, most common of them
are M. tuberculosis and M. lepra.
 Straight or slightly curved rod of about 3µm x 0.3µm
 Occurs either in pairs or small clumps.
 Gram Positive; but they resist decolorisation after being
stained with basic dyes ~ but they resist decolorisation
with 20% Sulphuric acid and absolute alcohol when
treated with acid fast stains.
Cultural Characteristics
O Colonies appear in about 2
weeks & sometimes may
take up to 8 weeks.
O OPTIMUM
TEMPERATURE is 37º C;
Growth doesn’t occur
above 40ºC or below
25ºC.
O OPTIMUM pH is 6.4 to 7
O M. tuberculosis are
eugonic.
O The organisms are highly
susceptible even to traces
of toxic substances
present in the media.
O Koch originally grew the
bacilli on heat coagulated
bovine serum.
O SOLID MEDIA:
CONTAINING EGG
* Lowenstein-Jensen
* Petragnini
* Dorset
CONTAINING
BLOOD,SERUM
* Tarshis
* Loeffler
CONTAINING POTATO
*Pawlowsky
O LIQUID MEDIA:
* Dubos
* Middlebrooks
* Proskauer & Beck’s
* Sula & Sauton’s
Cultural Differences of Liquid & Solid Media
Growth in Liquid
Media Growth in Solid Media
O Growth begins at the
bottom, without dispersing
the agents.
O The organisms creeps up
the sides and forms a
prominent surface pellicle
which extends along the
side of the medium.
O Diffuse growth is observed
in Dubos’ medium.
O Virulent strains form long
serpentine cords while a-
virulent strains grow in a
dispersed manner.
O Forms
dry, rough, raised, irregu
lar colonies with a
wrinkled surface.
O They are creamy-
white, becoming
yellowish or buff colored
on further incubation.
O They are tenacious and
not easily emulsified.
M. Tuberculosis as seen on Lowenstein-Jensen
Medium
Lifecycle of M. tuberculosis in Human
 Tuberculosis spreads through the air when a person with untreated
pulmonary TB coughs or sneezes. Once in the body, the tuberculosis
bacilli has about 5 stages in its life cycle:
 Stage 1: Onset
Bacteria is inhaled through the air and typically engulfed by alveolar
macrophages. At this instant, disease progression depends on the virulence
of the inhaled strain and the anti mycobacterial capabilities of the
macrophage in question. In some cases, the bacteria are able to reproduce
and initiate the infection. Tuberculosis begins when the inhaled
mycobacterial nuclei reach aveolar machrophages
Stage 2: Symbiosis
If the initial macrophage does not succeed in killing the bacteria, the
bacteria will replicate until the macrophage bursts. The bacteria are now
engulfed by other alveolar macrophages and non activated macrophages.
The macrophages that arrive from the bloodstream engulf the exposed
bacteria in a symbiotic manner—neither the host nor the bacteria is harmed
Contd
 Stage 3: Initial Caseous Necrosis
The next stage of disease development begins when bacterial reproduction
slows. Growth slows because as the bacteria reproduce, they kill all the
surrounding non activated macrophages and run out of cells to divide within.
In addition, the increased number of bacteria produces anoxic conditions
and reduces the local pH The bacteria can no longer reproduce in this
tubercule, but can remain alive for long periods of time at this state. The
host kills its own tissues to prevent the spread of the bacteria. Also at this
stage, the host will test positive for tuberculin.
Stage 4: Interplay of Tissue-Damaging and Macrophage Activating
Immune Response
Macrohpages surround the tubercule, some of which may be inactivate. M.
tuberculosis uses the inactive macrophages to reproduce, causing the
tubercule to grow. The tubercule may break off or spread into the
bronchus, and then other parts of the lung. If the tubercules reach the blood
stream, the patient can develop tuberculosis outside of the lungs, which is
known as milliary tuberculosis. Secondary lesion can develop almost
anywhere within the body, but are commonly found in the
bones, joints, lymph nodes, and genitourinary system.
Stage 5: Liquefaction and Cavity Formation
At some point the centres of the tubercles may liquefy, which produces a
very conducive environment for the bacteria and rapid spread of the
disease. Only a very small % of infected individuals will progress to this
stage.
Resistance of M. tuberculosis
 Heat Labile ~ Killed at 60ºC in 15 – 20 minutes.
 Cultures are killed by exposure to sunlight for 2 hours .
 Cultures remain viable at RT for 6 – 8 months and can stored
up to 2 years at -20ºC.
 Bacilli in sputum remain alive for 20 to 30 hours
in droplet nuclei are viable for 8 to 10 days.
 Bacilli are resistant to ~ Chemical disinfectants, 5%
phenols, 15% Sulphuric acid, 3% nitric acid, 5% Oxalic acid.
 But they are very sensitive to ~ Formaldehyde and
Gluteraldehyde. They are destroyed by tincture of Iodine in 5
minutes & by 80% ethanol in 2 to 10 minutes.
LABORATORY DIAGNOSIS:
o Demonstrating the bacilli in the lesion by microscopy
o Isolating the bacilli in the culture
o Transmitting the infection to experimental animals
o Demonstrating hypersensitivity to tuberculoprotein
PROPHYLAXIS: EARLY DETECTION AND
TREATMENT ~ IMMUNOPROPHYLAXIS
 Immunoprophylaxis
* By Intradermal Injections of live attenuated vaccine developed by
Calmette and Guerin in 1921, called BCG - Bacille Calmette Guerin .
* Injection of BCG in animals induces self limited infection with
production of small tubercles, thereby giving rise to delayed
hypersensitivity and immunity.
* BCG also has many complications :
Local: Abscess, Indolent ulcer, Tuberculoids, Confluent and lupoid
lesions.
Regional: Enlargement and Suppulation of draining Lymph nodes.
General: Fever, Mediastinal adenitis, Erythema nodosum, tendency
to keloid formation and rarely non-fatal meningitis.
 In TB endemic countries such as India, BCG vaccines are
administered to babies by intradermal injections immediately after
birth or as early as possible after that , but before age of 12 months.
 Babies born to AFB +ve mothers should be given BCG vaccine
ONLY AFTER a course of preventive chemotherapy.

More Related Content

What's hot

What's hot (20)

Mycobacteria
MycobacteriaMycobacteria
Mycobacteria
 
Bacterial Pathogenesis
Bacterial  PathogenesisBacterial  Pathogenesis
Bacterial Pathogenesis
 
Bacillus
Bacillus Bacillus
Bacillus
 
Staphylococcus aureus
Staphylococcus aureusStaphylococcus aureus
Staphylococcus aureus
 
Mycobacteria
Mycobacteria Mycobacteria
Mycobacteria
 
Spirochaetes
SpirochaetesSpirochaetes
Spirochaetes
 
13. e.coli
13. e.coli13. e.coli
13. e.coli
 
16. vibrio cholera
16. vibrio cholera16. vibrio cholera
16. vibrio cholera
 
Streptococcus
StreptococcusStreptococcus
Streptococcus
 
Subcutaneous mycoses.ppt
Subcutaneous mycoses.pptSubcutaneous mycoses.ppt
Subcutaneous mycoses.ppt
 
Mycobacterium tuberculosis
Mycobacterium  tuberculosisMycobacterium  tuberculosis
Mycobacterium tuberculosis
 
ClOSTRIDIUM perfringens
ClOSTRIDIUM perfringens ClOSTRIDIUM perfringens
ClOSTRIDIUM perfringens
 
Clostridium
ClostridiumClostridium
Clostridium
 
Medical Microbiology :Richettsia or rickettsiae
Medical Microbiology :Richettsia or rickettsiaeMedical Microbiology :Richettsia or rickettsiae
Medical Microbiology :Richettsia or rickettsiae
 
Cultivation of virus
Cultivation of virus Cultivation of virus
Cultivation of virus
 
Poliovirus
PoliovirusPoliovirus
Poliovirus
 
Neisseria gonorrhoeae lecture iii term
Neisseria gonorrhoeae lecture iii termNeisseria gonorrhoeae lecture iii term
Neisseria gonorrhoeae lecture iii term
 
Streptococcus pneumoniae
Streptococcus pneumoniaeStreptococcus pneumoniae
Streptococcus pneumoniae
 
Laboratory diagnosis of tuberculosis pract.
Laboratory diagnosis of tuberculosis pract.Laboratory diagnosis of tuberculosis pract.
Laboratory diagnosis of tuberculosis pract.
 
Mycobacterium
MycobacteriumMycobacterium
Mycobacterium
 

Viewers also liked (7)

Mycobacterium.ppt
Mycobacterium.pptMycobacterium.ppt
Mycobacterium.ppt
 
Mycobacterium tuberculosis
Mycobacterium tuberculosisMycobacterium tuberculosis
Mycobacterium tuberculosis
 
Mycobacterium tuberculosis seminar
Mycobacterium tuberculosis seminarMycobacterium tuberculosis seminar
Mycobacterium tuberculosis seminar
 
Mycobacteria
MycobacteriaMycobacteria
Mycobacteria
 
Mycobacterium
MycobacteriumMycobacterium
Mycobacterium
 
Mycobacterium Tuberculosis 2
Mycobacterium Tuberculosis 2Mycobacterium Tuberculosis 2
Mycobacterium Tuberculosis 2
 
Tuberculosis presentation
Tuberculosis presentationTuberculosis presentation
Tuberculosis presentation
 

Similar to Mycobacterium tuberculosis

Mycobacterium tuberculosis
Mycobacterium tuberculosisMycobacterium tuberculosis
Mycobacterium tuberculosis
Awaaz Batazoo
 
20 s2. tuberculosis, diptheria
20 s2. tuberculosis, diptheria20 s2. tuberculosis, diptheria
20 s2. tuberculosis, diptheria
Hasan Sultan
 
Mycobacterium tuberculosis
Mycobacterium tuberculosisMycobacterium tuberculosis
Mycobacterium tuberculosis
rubaiya kabir
 

Similar to Mycobacterium tuberculosis (20)

MLSM 505 Mycobact.pptx
MLSM 505 Mycobact.pptxMLSM 505 Mycobact.pptx
MLSM 505 Mycobact.pptx
 
Mycobacterium spp.ppt
Mycobacterium spp.pptMycobacterium spp.ppt
Mycobacterium spp.ppt
 
MLSM 505 Mycobact.ppt
MLSM 505 Mycobact.pptMLSM 505 Mycobact.ppt
MLSM 505 Mycobact.ppt
 
MYCOBACTERIUM TUBERCULOSIS
MYCOBACTERIUM TUBERCULOSISMYCOBACTERIUM TUBERCULOSIS
MYCOBACTERIUM TUBERCULOSIS
 
Mycobacterium tuberculosis
Mycobacterium tuberculosisMycobacterium tuberculosis
Mycobacterium tuberculosis
 
20 s2. tuberculosis, diptheria
20 s2. tuberculosis, diptheria20 s2. tuberculosis, diptheria
20 s2. tuberculosis, diptheria
 
Tuberculosis
TuberculosisTuberculosis
Tuberculosis
 
Mycobacterium Tuberculosis.pptx
Mycobacterium Tuberculosis.pptxMycobacterium Tuberculosis.pptx
Mycobacterium Tuberculosis.pptx
 
Tuberculosis
TuberculosisTuberculosis
Tuberculosis
 
Mycobacterium .pptx
Mycobacterium .pptxMycobacterium .pptx
Mycobacterium .pptx
 
Mycobacterium.ppt bacterial diseases. Tb
Mycobacterium.ppt bacterial diseases. TbMycobacterium.ppt bacterial diseases. Tb
Mycobacterium.ppt bacterial diseases. Tb
 
Comparative computational analysis of mycobacterium species by using differen...
Comparative computational analysis of mycobacterium species by using differen...Comparative computational analysis of mycobacterium species by using differen...
Comparative computational analysis of mycobacterium species by using differen...
 
Infectious Diseases.pptx
Infectious Diseases.pptxInfectious Diseases.pptx
Infectious Diseases.pptx
 
Mycobacterium tuberculosis
Mycobacterium tuberculosisMycobacterium tuberculosis
Mycobacterium tuberculosis
 
Mycobacterium
MycobacteriumMycobacterium
Mycobacterium
 
Mycobacterium
MycobacteriumMycobacterium
Mycobacterium
 
Mycobacterium tuberculosis by Sikander ali Sumalani
Mycobacterium tuberculosis by Sikander ali SumalaniMycobacterium tuberculosis by Sikander ali Sumalani
Mycobacterium tuberculosis by Sikander ali Sumalani
 
Mycobacterium tuberculosis and Mycobacterium leprae
Mycobacterium tuberculosis and Mycobacterium leprae Mycobacterium tuberculosis and Mycobacterium leprae
Mycobacterium tuberculosis and Mycobacterium leprae
 
Tuberculosis
TuberculosisTuberculosis
Tuberculosis
 
Mycobacteria. Agents of Tuberculosis & Leprae. Atypical Mycobacteria
Mycobacteria. Agents of Tuberculosis & Leprae. Atypical MycobacteriaMycobacteria. Agents of Tuberculosis & Leprae. Atypical Mycobacteria
Mycobacteria. Agents of Tuberculosis & Leprae. Atypical Mycobacteria
 

More from Archa Dave (11)

Wine making
Wine makingWine making
Wine making
 
Staphylococcal Skin Infections
Staphylococcal Skin InfectionsStaphylococcal Skin Infections
Staphylococcal Skin Infections
 
Bread and cheese
Bread and cheeseBread and cheese
Bread and cheese
 
Lyme and syphilis
Lyme and syphilisLyme and syphilis
Lyme and syphilis
 
App of enzymes in dairy industry
App of enzymes in dairy industryApp of enzymes in dairy industry
App of enzymes in dairy industry
 
Raman fluorescencespec
Raman fluorescencespecRaman fluorescencespec
Raman fluorescencespec
 
Ngs ppt
Ngs pptNgs ppt
Ngs ppt
 
Genetic code
Genetic codeGenetic code
Genetic code
 
Ppt flagella seminar
Ppt flagella seminarPpt flagella seminar
Ppt flagella seminar
 
Zoonotic diseases
Zoonotic diseasesZoonotic diseases
Zoonotic diseases
 
Water borne diseases
Water borne diseasesWater borne diseases
Water borne diseases
 

Recently uploaded

Call Girls in Gagan Vihar (delhi) call me [🔝 9953056974 🔝] escort service 24X7
Call Girls in Gagan Vihar (delhi) call me [🔝  9953056974 🔝] escort service 24X7Call Girls in Gagan Vihar (delhi) call me [🔝  9953056974 🔝] escort service 24X7
Call Girls in Gagan Vihar (delhi) call me [🔝 9953056974 🔝] escort service 24X7
9953056974 Low Rate Call Girls In Saket, Delhi NCR
 
Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls * UPA...
Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls  * UPA...Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls  * UPA...
Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls * UPA...
mahaiklolahd
 

Recently uploaded (20)

Call Girls Rishikesh Just Call 9667172968 Top Class Call Girl Service Available
Call Girls Rishikesh Just Call 9667172968 Top Class Call Girl Service AvailableCall Girls Rishikesh Just Call 9667172968 Top Class Call Girl Service Available
Call Girls Rishikesh Just Call 9667172968 Top Class Call Girl Service Available
 
Saket * Call Girls in Delhi - Phone 9711199012 Escorts Service at 6k to 50k a...
Saket * Call Girls in Delhi - Phone 9711199012 Escorts Service at 6k to 50k a...Saket * Call Girls in Delhi - Phone 9711199012 Escorts Service at 6k to 50k a...
Saket * Call Girls in Delhi - Phone 9711199012 Escorts Service at 6k to 50k a...
 
Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...
Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...
Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...
 
8980367676 Call Girls In Ahmedabad Escort Service Available 24×7 In Ahmedabad
8980367676 Call Girls In Ahmedabad Escort Service Available 24×7 In Ahmedabad8980367676 Call Girls In Ahmedabad Escort Service Available 24×7 In Ahmedabad
8980367676 Call Girls In Ahmedabad Escort Service Available 24×7 In Ahmedabad
 
Call Girls Ahmedabad Just Call 9630942363 Top Class Call Girl Service Available
Call Girls Ahmedabad Just Call 9630942363 Top Class Call Girl Service AvailableCall Girls Ahmedabad Just Call 9630942363 Top Class Call Girl Service Available
Call Girls Ahmedabad Just Call 9630942363 Top Class Call Girl Service Available
 
Premium Call Girls In Jaipur {8445551418} ❤️VVIP SEEMA Call Girl in Jaipur Ra...
Premium Call Girls In Jaipur {8445551418} ❤️VVIP SEEMA Call Girl in Jaipur Ra...Premium Call Girls In Jaipur {8445551418} ❤️VVIP SEEMA Call Girl in Jaipur Ra...
Premium Call Girls In Jaipur {8445551418} ❤️VVIP SEEMA Call Girl in Jaipur Ra...
 
Call Girls Rishikesh Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Rishikesh Just Call 8250077686 Top Class Call Girl Service AvailableCall Girls Rishikesh Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Rishikesh Just Call 8250077686 Top Class Call Girl Service Available
 
Models Call Girls In Hyderabad 9630942363 Hyderabad Call Girl & Hyderabad Esc...
Models Call Girls In Hyderabad 9630942363 Hyderabad Call Girl & Hyderabad Esc...Models Call Girls In Hyderabad 9630942363 Hyderabad Call Girl & Hyderabad Esc...
Models Call Girls In Hyderabad 9630942363 Hyderabad Call Girl & Hyderabad Esc...
 
Most Beautiful Call Girl in Bangalore Contact on Whatsapp
Most Beautiful Call Girl in Bangalore Contact on WhatsappMost Beautiful Call Girl in Bangalore Contact on Whatsapp
Most Beautiful Call Girl in Bangalore Contact on Whatsapp
 
Call Girls Service Jaipur {8445551418} ❤️VVIP BHAWNA Call Girl in Jaipur Raja...
Call Girls Service Jaipur {8445551418} ❤️VVIP BHAWNA Call Girl in Jaipur Raja...Call Girls Service Jaipur {8445551418} ❤️VVIP BHAWNA Call Girl in Jaipur Raja...
Call Girls Service Jaipur {8445551418} ❤️VVIP BHAWNA Call Girl in Jaipur Raja...
 
Independent Call Girls Service Mohali Sector 116 | 6367187148 | Call Girl Ser...
Independent Call Girls Service Mohali Sector 116 | 6367187148 | Call Girl Ser...Independent Call Girls Service Mohali Sector 116 | 6367187148 | Call Girl Ser...
Independent Call Girls Service Mohali Sector 116 | 6367187148 | Call Girl Ser...
 
💕SONAM KUMAR💕Premium Call Girls Jaipur ↘️9257276172 ↙️One Night Stand With Lo...
💕SONAM KUMAR💕Premium Call Girls Jaipur ↘️9257276172 ↙️One Night Stand With Lo...💕SONAM KUMAR💕Premium Call Girls Jaipur ↘️9257276172 ↙️One Night Stand With Lo...
💕SONAM KUMAR💕Premium Call Girls Jaipur ↘️9257276172 ↙️One Night Stand With Lo...
 
Call Girls in Gagan Vihar (delhi) call me [🔝 9953056974 🔝] escort service 24X7
Call Girls in Gagan Vihar (delhi) call me [🔝  9953056974 🔝] escort service 24X7Call Girls in Gagan Vihar (delhi) call me [🔝  9953056974 🔝] escort service 24X7
Call Girls in Gagan Vihar (delhi) call me [🔝 9953056974 🔝] escort service 24X7
 
Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...
Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...
Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...
 
(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...
(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...
(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...
 
Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls * UPA...
Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls  * UPA...Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls  * UPA...
Call Girl in Indore 8827247818 {LowPrice} ❤️ (ahana) Indore Call Girls * UPA...
 
VIP Hyderabad Call Girls Bahadurpally 7877925207 ₹5000 To 25K With AC Room 💚😋
VIP Hyderabad Call Girls Bahadurpally 7877925207 ₹5000 To 25K With AC Room 💚😋VIP Hyderabad Call Girls Bahadurpally 7877925207 ₹5000 To 25K With AC Room 💚😋
VIP Hyderabad Call Girls Bahadurpally 7877925207 ₹5000 To 25K With AC Room 💚😋
 
Call Girls Vasai Virar Just Call 9630942363 Top Class Call Girl Service Avail...
Call Girls Vasai Virar Just Call 9630942363 Top Class Call Girl Service Avail...Call Girls Vasai Virar Just Call 9630942363 Top Class Call Girl Service Avail...
Call Girls Vasai Virar Just Call 9630942363 Top Class Call Girl Service Avail...
 
Coimbatore Call Girls in Coimbatore 7427069034 genuine Escort Service Girl 10...
Coimbatore Call Girls in Coimbatore 7427069034 genuine Escort Service Girl 10...Coimbatore Call Girls in Coimbatore 7427069034 genuine Escort Service Girl 10...
Coimbatore Call Girls in Coimbatore 7427069034 genuine Escort Service Girl 10...
 
Independent Call Girls In Jaipur { 8445551418 } ✔ ANIKA MEHTA ✔ Get High Prof...
Independent Call Girls In Jaipur { 8445551418 } ✔ ANIKA MEHTA ✔ Get High Prof...Independent Call Girls In Jaipur { 8445551418 } ✔ ANIKA MEHTA ✔ Get High Prof...
Independent Call Girls In Jaipur { 8445551418 } ✔ ANIKA MEHTA ✔ Get High Prof...
 

Mycobacterium tuberculosis

  • 2.  Slender rods that sometimes show branching filamentous forms resembling fungal mycelium.  In liquid cultures they form a mold-like pellicle~ hence the name ‘mycobacterium’ = Fungus like bacteria.  They are acid-fast, aerobic, non-motile, non-capsulated and non-sporing, obligate parasites, opportunistic pathogens and saprophytes.  Robert Koch in 1882, isolated the mammalian strain and proved its causative role in Tuberculosis.  Mycobacterium has many bacilli, most common of them are M. tuberculosis and M. lepra.
  • 3.  Straight or slightly curved rod of about 3µm x 0.3µm  Occurs either in pairs or small clumps.  Gram Positive; but they resist decolorisation after being stained with basic dyes ~ but they resist decolorisation with 20% Sulphuric acid and absolute alcohol when treated with acid fast stains.
  • 4. Cultural Characteristics O Colonies appear in about 2 weeks & sometimes may take up to 8 weeks. O OPTIMUM TEMPERATURE is 37º C; Growth doesn’t occur above 40ºC or below 25ºC. O OPTIMUM pH is 6.4 to 7 O M. tuberculosis are eugonic. O The organisms are highly susceptible even to traces of toxic substances present in the media. O Koch originally grew the bacilli on heat coagulated bovine serum. O SOLID MEDIA: CONTAINING EGG * Lowenstein-Jensen * Petragnini * Dorset CONTAINING BLOOD,SERUM * Tarshis * Loeffler CONTAINING POTATO *Pawlowsky O LIQUID MEDIA: * Dubos * Middlebrooks * Proskauer & Beck’s * Sula & Sauton’s
  • 5. Cultural Differences of Liquid & Solid Media Growth in Liquid Media Growth in Solid Media O Growth begins at the bottom, without dispersing the agents. O The organisms creeps up the sides and forms a prominent surface pellicle which extends along the side of the medium. O Diffuse growth is observed in Dubos’ medium. O Virulent strains form long serpentine cords while a- virulent strains grow in a dispersed manner. O Forms dry, rough, raised, irregu lar colonies with a wrinkled surface. O They are creamy- white, becoming yellowish or buff colored on further incubation. O They are tenacious and not easily emulsified.
  • 6. M. Tuberculosis as seen on Lowenstein-Jensen Medium
  • 7. Lifecycle of M. tuberculosis in Human  Tuberculosis spreads through the air when a person with untreated pulmonary TB coughs or sneezes. Once in the body, the tuberculosis bacilli has about 5 stages in its life cycle:  Stage 1: Onset Bacteria is inhaled through the air and typically engulfed by alveolar macrophages. At this instant, disease progression depends on the virulence of the inhaled strain and the anti mycobacterial capabilities of the macrophage in question. In some cases, the bacteria are able to reproduce and initiate the infection. Tuberculosis begins when the inhaled mycobacterial nuclei reach aveolar machrophages Stage 2: Symbiosis If the initial macrophage does not succeed in killing the bacteria, the bacteria will replicate until the macrophage bursts. The bacteria are now engulfed by other alveolar macrophages and non activated macrophages. The macrophages that arrive from the bloodstream engulf the exposed bacteria in a symbiotic manner—neither the host nor the bacteria is harmed
  • 8. Contd  Stage 3: Initial Caseous Necrosis The next stage of disease development begins when bacterial reproduction slows. Growth slows because as the bacteria reproduce, they kill all the surrounding non activated macrophages and run out of cells to divide within. In addition, the increased number of bacteria produces anoxic conditions and reduces the local pH The bacteria can no longer reproduce in this tubercule, but can remain alive for long periods of time at this state. The host kills its own tissues to prevent the spread of the bacteria. Also at this stage, the host will test positive for tuberculin. Stage 4: Interplay of Tissue-Damaging and Macrophage Activating Immune Response Macrohpages surround the tubercule, some of which may be inactivate. M. tuberculosis uses the inactive macrophages to reproduce, causing the tubercule to grow. The tubercule may break off or spread into the bronchus, and then other parts of the lung. If the tubercules reach the blood stream, the patient can develop tuberculosis outside of the lungs, which is known as milliary tuberculosis. Secondary lesion can develop almost anywhere within the body, but are commonly found in the bones, joints, lymph nodes, and genitourinary system. Stage 5: Liquefaction and Cavity Formation At some point the centres of the tubercles may liquefy, which produces a very conducive environment for the bacteria and rapid spread of the disease. Only a very small % of infected individuals will progress to this stage.
  • 9. Resistance of M. tuberculosis  Heat Labile ~ Killed at 60ºC in 15 – 20 minutes.  Cultures are killed by exposure to sunlight for 2 hours .  Cultures remain viable at RT for 6 – 8 months and can stored up to 2 years at -20ºC.  Bacilli in sputum remain alive for 20 to 30 hours in droplet nuclei are viable for 8 to 10 days.  Bacilli are resistant to ~ Chemical disinfectants, 5% phenols, 15% Sulphuric acid, 3% nitric acid, 5% Oxalic acid.  But they are very sensitive to ~ Formaldehyde and Gluteraldehyde. They are destroyed by tincture of Iodine in 5 minutes & by 80% ethanol in 2 to 10 minutes.
  • 10. LABORATORY DIAGNOSIS: o Demonstrating the bacilli in the lesion by microscopy o Isolating the bacilli in the culture o Transmitting the infection to experimental animals o Demonstrating hypersensitivity to tuberculoprotein
  • 11. PROPHYLAXIS: EARLY DETECTION AND TREATMENT ~ IMMUNOPROPHYLAXIS  Immunoprophylaxis * By Intradermal Injections of live attenuated vaccine developed by Calmette and Guerin in 1921, called BCG - Bacille Calmette Guerin . * Injection of BCG in animals induces self limited infection with production of small tubercles, thereby giving rise to delayed hypersensitivity and immunity. * BCG also has many complications : Local: Abscess, Indolent ulcer, Tuberculoids, Confluent and lupoid lesions. Regional: Enlargement and Suppulation of draining Lymph nodes. General: Fever, Mediastinal adenitis, Erythema nodosum, tendency to keloid formation and rarely non-fatal meningitis.  In TB endemic countries such as India, BCG vaccines are administered to babies by intradermal injections immediately after birth or as early as possible after that , but before age of 12 months.  Babies born to AFB +ve mothers should be given BCG vaccine ONLY AFTER a course of preventive chemotherapy.