Mycobacterium tuberculosis and atypical Mycobacteria

BDS

3-4-15

1Mycobacteria

Features2

Mycobacterium tuberculosisPathogenesis

3Mycobacterium

tuberculosisLab Diagnosis

4Atypical

MycobacteriaClassification

5Atypical

MycobacteriaFeatures

MycobacteriaFeatures

Staining Properties

Mycobacterium tuberculosisTransmission and Epidemiology

1.7 Million Deaths9 Million New Cases

Mycobacterium bovisIntestinal Tuberculosis

Mycobacterium tuberculosisGrowth & Medium

Mycobacterium tuberculosisCell Wall & Cord Factor

Trehalose Dimycolate

Mycobacterium tuberculosisPathogenesis

Lesions

1. Exudative Lesions2. Granulomatous Lesions

Mycobacterium tuberculosisPathogenesis

Ghon Complex

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

Medically Important Mycobacteria

Atypical MycobacteriaRunyon’s Classification

1. Photochromogens2. Schotochromogens3. Nonchromogens4. Rapid Growers

Group 1Photochromogens

Mycobacterium kansasi and M. marinumM. 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

Group 2Scotochromogens

Mycobacterium scrofulacium

• Causes lymphadenitis

Group 3Nonchromochromogens

Mycobacterium avium and M. intracellulareMycobacterium avium intracellulare complex

• Cause tuberculosis like illness usually in immunocompromisedpatients

• Highly resistant to antituberculosis drugs

Group 4Rapid Growers

Mycobacterium fortuitum and M. cheloneiMycobacterium 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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