This document discusses Mycobacterium tuberculosis and atypical mycobacteria. M. tuberculosis causes tuberculosis in humans, infecting over 9 million people and killing 1.7 million annually. It is transmitted between people and can cause lesions in the lungs. Diagnosis involves smear examination, culture, identification, and susceptibility testing. Atypical mycobacteria are classified into four groups - photochromogens, scotochromogens, nonchromogens, and rapid growers. Some important atypical species include M. kansasii, M. marinum, M. scrofulacium, M. avium complex, and M. fortuitum complex, which can cause disease in humans but are generally more resistant

1. Mycobacterium tuberculosis and
atypical Mycobacteria
BDS
3-4-15

2. 1
Mycobacteria
Features
2
Mycobacterium
tuberculosis
Pathogenesis
3
Mycobacterium
tuberculosis
Lab Diagnosis
4
Atypical
Mycobacteria
Classification
5
Atypical
Mycobacteria
Features

3. Mycobacteria
Features
Staining Properties

4. Mycobacterium tuberculosis
Transmission and Epidemiology
1.7 Million Deaths
9 Million New Cases
Mycobacterium bovis
Intestinal Tuberculosis

5. Mycobacterium tuberculosis
Growth & Medium

6. Mycobacterium tuberculosis
Cell Wall & Cord Factor
Trehalose Dimycolate

7. Mycobacterium tuberculosis
Pathogenesis
Lesions
1. Exudative Lesions
2. Granulomatous Lesions

8. Mycobacterium tuberculosis
Pathogenesis
Ghon Complex

9. Diagnosis of tuberculosis
Latent Infection Active tuberculosis
Smear examination
Solid and liquid culture
Identification
Susceptibility testing methods
TST
IFN- techniques
Molecular methods
-Detection
-Identification
-Detection of resistance
9

10. Medically Important Mycobacteria

11. Atypical Mycobacteria
Runyon’s Classification
1. Photochromogens
2. Schotochromogens
3. Nonchromogens
4. Rapid Growers

12. Group 1
Photochromogens
Mycobacterium kansasi and M. marinum
M. kansasii
• Causes lung disease clinically resembling tuberculosis.
• It is susceptible to the standard antituberculosis drugs.
Mycobacterium marinum
• Causes "swimming pool or "fish tank” granuloma .
• These granulomatous, ulcerating lesions occur in the skin at the site
of abrasions incurred at swimming pools and aquariums.
• Treatment with a tetracyclines

13. Group 2
Scotochromogens
Mycobacterium scrofulacium
• Causes lymphadenitis

14. Group 3
Nonchromochromogens
Mycobacterium avium and M. intracellulare
Mycobacterium avium intracellulare complex
• Cause tuberculosis like illness usually in immunocompromised
patients
• Highly resistant to antituberculosis drugs

15. Group 4
Rapid Growers
Mycobacterium fortuitum and M. chelonei
Mycobacterium fortuitum-chelonei complex
• Rarely cause human disease.
• Infections occur in immunocompomised patients and patients
with catheters or prosthetic joints.
• Resistant to antituberculous drugs.

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