MycoBACTERIUM leprae - Microbiology - Presentation

This presentation on mycobacterium leprae with information about their
Morphology, pathogenesis, diagnosis, treatment and Prognosis

1. MYCOBACTERIUM
LEPRAE
Microbiology
Created : Jai Kumar Panthi

2. TABLE OF CONTENT
Introduction 1.
Morphology2.
Pathogenesis3.
Transmission4.
Diagnosis 5.
Treatment 6.
Epidemiology 7.
Prevention and Control 8.
Historical Perspective 9.
An In-Depth Look at the Bacterium Behind Leprosy

3. MYCOBACTERIUM LEPRAE
Overview of Mycobacterium leprae
INTRODUCTION
Mycobacterium leprae is a bacterium responsible for causing
leprosy, also known as Hansen's disease.
Leprosy is a chronic infectious disease that primarily affects
the skin, peripheral nerves, upper respiratory tract, and
eyes.

4. MYCOBACTERIUM LEPRAE

5. Shape: Rod-shaped (bacillus)
Staining: Acid-fast positive due to mycolic acid in
the cell wall
Size: 1-8 µm in length and 0.2-0.5 µm in diameter
MORPHOLOGY

6. ORGANS AFFECTED BY
MYCOBACTERIUM LEPRAE
1. Skin:
Lesions: Hypopigmented or erythematous patches.
Sensory Loss: Numbness in affected areas.
Ulceration: Chronic ulcers due to secondary infections.

7. 2. Peripheral Nerves:
Lesions: Hypopigmented or erythematous patches.
Sensory Loss: Numbness in affected areas.
Ulceration: Chronic ulcers due to secondary infections.
3. Eyes:
Eyelid Function: Lagophthalmos (inability to close
eyelids).
Corneal Damage: Risk of ulcers and blindness.
Iritis: Inflammation of the iris affecting vision.

8. 4. Upper Respiratory Tract:
Nasal Mucosa: Chronic congestion, nosebleeds, nasal
collapse.
Larynx: Hoarseness and breathing difficulties.
5. Bones and Joints:
Bone Changes: Resorption and shortening of fingers
and toes.
Arthritis: Joint inflammation and pain.

9. 6. Reproductive System:
Testicular Involvement: Orchitis, infertility, decreased
testosterone.
Gynecomastia: Enlarged breast tissue in men.
7. Lymphatic System:
Lymph Nodes: Swelling and tenderness.

10. PATHOGENESIS
1. Entry into the Host:
Respiratory Tract: Inhalation of respiratory droplets
from an infected person.
Skin: Entry through breaks or lesions in the skin.
2. Initial Infection:
Target Cells: Bacteria invade and infect macrophages
and Schwann cells in peripheral nerves.

11. 3. Survival and Replication:
Intracellular Survival: M. leprae survives within
macrophages and Schwann cells due to its thick, waxy
cell wall.
Slow Replication: Doubling time of 12-14 days,
contributing to a long incubation period (2-10 years).
4. Immune Response:
Strong Cell-Mediated Immunity (CMI): Localized infection
(Tuberculoid Leprosy).

12. 5. Clinical Manifestations:
Tuberculoid Leprosy: Few, well-defined lesions, localized
nerve damage.
Lepromatous Leprosy: Numerous, poorly defined
lesions, extensive nerve damage.
Borderline and Indeterminate Forms: Intermediate
presentations.

13. 6. Nerve Damage:
Mechanism: Infection and demyelination of Schwann
cells, inflammatory responses.
Consequences: Sensory loss, muscle weakness,
deformities (e.g., claw hand, foot drop).

14. 7. Complications
Secondary Infections: Due to loss of sensation.
Reactions:
Type 1 (Reversal Reaction): Increased immune response
causing lesion and nerve exacerbation.
1.
Type 2 (Erythema Nodosum Leprosum): Immune
complex inflammation with painful nodules and
systemic symptoms.
2.

15. TRANSMISSION
Primary Route: Prolonged close contact with an
infected person.
Other Possible Routes: Through respiratory
droplets or skin lesions.
Incubation Period: Long, typically 2-10 years.

16. DIAGNOSIS
Clinical Examination:
Skin Lesions: Look for hypopigmented or reddish patches
with loss of sensation.
Lesions may be dry, scaly, or ulcerated.
Nerve
Involvement:
Check for thickened peripheral nerves.
Assess for loss of sensation, particularly in
cooler areas of the body like hands, feet,
and face.
Test for muscle weakness or paralysis.

17. Laboratory Tests:
Skin Smears: Ziehl-Neelsen Stain: Staining technique to
identify acid-fast bacilli in skin smears.
Collect samples from the earlobes, elbows,
and lesions.
Biopsy: Skin or nerve biopsy to look for granulomas
and acid-fast bacilli under a microscope.
Histopathological examination to
distinguish between different forms of
leprosy.

18. Serological Tests:
Antibody
Detection:
Tests to detect antibodies against M.
leprae-specific antigens.
Used mainly in research and surveillance,
not routine diagnosis.
Differential Diagnosis:
Exclude Other
Conditions:
Rule out other diseases with similar
symptoms, such as fungal infections,
psoriasis, and other causes of peripheral
neuropathy.

19. Clinical Criteria for Classification:
Tuberculoid
Leprosy:
Few well-defined lesions with significant
sensory loss.
Positive skin smear in less than 5% of lesions.
Lepromatous
Leprosy:
Few well-defined lesions with significant
sensory loss.
Positive skin smear in less than 5% of lesions.
Borderline and
Indeterminate
Forms:
Mixed features of both tuberculoid and
lepromatous leprosy.
Variable skin smear results.

20. Biochemical Diagnosis :
Lepromin Skin
Test:
Purpose: Detects delayed-type
hypersensitivity to M. leprae antigens.
Result: Positive in tuberculoid leprosy;
indicates prior exposure.
Polymerase
Chain Reaction
(PCR):
Purpose: Detects M. leprae DNA.
Method: DNA extraction from skin biopsies,
nasal swabs, or tissues.
Result: Positive confirms presence of M.
leprae.

21. Phenolic
Glycolipid-I
(PGL-I)
Serology:
Purpose: Detects antibodies against M.
leprae-specific PGL-I antigen.
Method: ELISA or rapid
immunochromatographic tests.
Result: Positive indicates exposure to M.
leprae.

22. Lipoarabinoma
nnan (LAM)
Test:
Purpose: Detects LAM antigen in urine or
serum.
Method: Immunoassay techniques like
ELISA.
Result: Positive indicates active M. leprae
infection, useful in high bacterial load cases.

23. TREATMENT
Multi-Drug Therapy (MDT):
Combination of Dapsone, Rifampicin, and Clofazimine.1.
Treatment duration ranges from 6 months to 1 year.2.
Effectiveness :
MDT is highly effective and can cure the disease.

24. EPIDEMIOLOGY
Global Distribution:
Leprosy is found worldwide, but it is most prevalent in
tropical and subtropical regions.
Global Distribution:
The majority of cases are reported from a few
countries, primarily:
India 1.
Brazil2.
Indonesia 3.

25. Prevalence:
Annually, over 200,000 new cases are reported globally.
The World Health Organization (WHO) classifies
countries based on the number of new cases per year,
with endemic countries having higher case numbers.
Transmission Dynamics:
Leprosy primarily spreads through prolonged close
contact with an infected person, particularly via
respiratory droplets.
Skin contact with infected individuals can also
contribute to transmission.

26. Demographics:
Both sexes and all age groups can be affected, but it is
more commonly diagnosed in adults.
The disease has a long incubation period (typically 2-10
years), meaning many people are exposed long before
symptoms appear.
Public Health Impact:
Leprosy is associated with significant social stigma and
disability, affecting quality of life and mental health.
Efforts to reduce stigma and support patients are
critical for effective disease management.

27. Control and Elimination Efforts:
WHO has implemented strategies to eliminate leprosy
as a public health problem, defined as less than one
case per 10,000 population.
Early detection, prompt treatment with multi-drug
therapy (MDT), and public health education are key
components of these efforts.

28. PREVENTION AND CONTROL
Public Health Measures:
Early diagnosis and treatment.
Contact tracing and monitoring.
Education and awareness campaigns.
Vaccination:
Bacillus Calmette-Guérin (BCG) vaccine provides
some protection.

29. HISTORICAL PERSPECTIVE
Ancient History: Evidence of leprosy in ancient
civilizations (e.g., Egypt, China).
Stigma and Isolation: Historical social stigma associated
with leprosy.
Modern Efforts: World Health Organization (WHO)
initiatives to eliminate leprosy as a public health
problem.

30. THANK YOU
@jaikumarpanthi