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Mycobacteria. Causative agents of tuberculosis. Pathogenesis, laboratory diagnostics, prophylaxis and therapy of diseases caused by mycobacteria. Vinnitsa.

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Presentation on theme: "Mycobacteria. Causative agents of tuberculosis. Pathogenesis, laboratory diagnostics, prophylaxis and therapy of diseases caused by mycobacteria. Vinnitsa."— Presentation transcript:

1 Mycobacteria. Causative agents of tuberculosis. Pathogenesis, laboratory diagnostics, prophylaxis and therapy of diseases caused by mycobacteria. Vinnitsa National Pirogov Memorial Medical University / Department of microbiology

2 Taxonomy and classification of mycobacteria Family Mycobacteriacea Genus Mycobacterium includes about 40 species Pathogenic mycobacteria: Species causing tuberculosis:M.tuberculosis, M.bovis, M.africanum, M.microtii Species causing leprosy is M.leprae

3 Morphology of tubercle bacilli

4 Cultivation of M.tuberculosis It is obligate aerobe with the slow growth in culture Optimum temperature is 37 0 C, growth range is between 25 0 C and 40 0 C Optimum pH is 6.4-7.0 Culture media for tubercle bacilli Lowenstein-Jensen potato-glycerol broth citrate blood

5 Colonies of M.tuberculosis on the LJ nutrient medium

6 Virulent factors of tubercle bacilli Cord –factor Fatty acids, lipids tuberculoprotein

7 Epidemiology of tuberculosis The source of tubercle bacilli may be: Humans Animals Tuberculosis is air-borne infection. The mode of transmission is by direct inhalation Infection with M.bovis arises by ingestion of contaminated non-pasteurized milk and dairy products

8 Main clinical signs of tuberculosis A person with active TB will have the following symptoms that get more severe over time  a bad cough that is worse in the morning  chest pain  greenish or bloody sputum  weakness or fatigue  weight loss  night sweats  chills  fever

9 X-ray examination of person with tuberculosis

10 Laboratory diagnostics (microscopy) 1. Microscopy : Direct microscopy Fluorescent microscopy 2. Culture method 3. Biological or experimental infection 4. Allergic test (Mantoux test) 5. Serology

11 Immunofluorescence test Direct microscopy after Zheel-Neelsen staining

12 Mantoux test

13 Prevention and treatment of tuberculosis in persons with positive test Immunoprophylaxis is with alive attenuated BCG vaccine Persons with negative Mantoux test must be vaccinated with BCG vaccine

14 Therapy Specific antituberculous chemotherapeutic drugs are used: Isoniasid Ethambutol Pyrazinamide Rifampicin Streptomycin

15 M.leprae

16 Cultural properties It is not cultivated onto nutrient media (!) Experimental infection may be caused - by injection into foot of mouse – local change - by infection of armadillo (tatou)– generalized infection Virulent factors : microcapsule, fatty acids, cord-factor, allergins (lepromin)

17 Epidemiology Source of infection – a person with lepromatous form Route of transmission - By inhalation of air droplets - By direct contact Leprosy is low contagious endemic disease (!)

18 Pathogenesis Due to immunological reactiveness of host there are two types of leprosy: - ТТ – tuberculoid type - LT– lepromatous type - intermediate type

19 Tyberculoid type of leprosy

20 Lepromatous type

21 Laboratory diagnostics Microscopy Serology Allergic skin test with lepromin

22 Mycobacteria


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