The document provides historical and scientific information about Mycobacterium tuberculosis: 1) M. tuberculosis has been affecting humans for thousands of years and was a major cause of death in Europe between 1500-1900 AD. 2) In the late 19th/early 20th century, scientists like Robert Koch and Selman Waksman made discoveries that enabled the definitive diagnosis and treatment of tuberculosis. 3) M. tuberculosis is classified as a slow-growing typical mycobacterium within the Mycobacterium tuberculosis complex, and its cell wall structure and components allow it to cause disease.

1. Mycobacterium tuberculosis Dr Kamran Afzal Asst Prof Microbiology

2. Tuberculosis - The Captain of Death

3. Historical background Neolithic time 2400 BC - Egyptian mummies spinal columns 460 BC Hippocrates, Greece First clinical description: Phthisis / Consumption 500-1500 AD Roman occupation of Europe, it spread to Britain 1650-1900 AD ‘ White plague’ of Europe 1:5 deaths

4. 1890 (Robert Koch) Discovery of staining technique that identified Bacillus tuberculosis Definite diagnosis made possible and thus treatment could begin Tuberculin’s diagnostic use discovered

5. 1908-1920 Vaccine (BCG) 1943 (Selman Abraham Waksman) Streptomycin discovered Injections dramatically recovered TB patients

6. Mycobacteria The name mycobacterium means “fungus bacterium” due to fungus-like pellicle formed by Mycobacterium tuberculosis in liquid media

7. Species differentiation Order - Actinomycetales Family - Mycobacteriaceae Genus - Mycobacterium Usually grouped into 2 divisions Typical mycobacteria (MTb Complex) Atypical mycobacteria Slow growing > 7 days Rapidly growing < 7 days

8. Mycobacterium tuberculosis Complex Mycobacterium tuberculosis Mycobacterium bovis Mycobacterium africanum Mycobacterium microti Mycobacterium canetii

9. M.avium-intracellulare complex M. scrofulaceum M. xenopi M. paratuberculosis M. malmoense M. marinum M. farcinogenes M. k ansasii M. haemophilum M. chelonae M. fortuitum M. ulcerans M. intermedium Mycobacteria other than tuberculosis (MOTT) Atypical Mycobacteria Nontuberculous Mycobacteria (NTM)

10. Gen Characteristics - Mycobacteria 80 species, 20 are known pathogens Gram positive but are not easily stained Non-encapsulated and do not form spores Acid-fast Resistant to drying and chemical disinfectants but sensitive to heat and UVL

11. Lipids (60% of the cell wall weight) Mycolic acid – responsible for acid fastness Phospholipids – induce caseation necrosis Cord factor (trehaloses) Present in virulent strains that grow in a cord like pattern It inhibits migration of leukocytes Causes chronic granulomas Components of cell wall

12. Protein Tuberculin reaction Elicit formation of antibodies Granuloma formation Lipopolysaccharides (Lipoarabinomannan LAM) Inhibition of macrophage activation by IFN Release of cytokines (TNF  ) from macrophages which causes fever, weight loss and tissue damage

13. Cell Wall Structure

14. Mycobacterium tuberculosis (AFB)