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Experiment seven Mycobacterium tuberculosis

Experiment seven Mycobacterium tuberculosis. Pathogenesis. primary infection 1) lung infection secondary infection 2) Out lung infection . Who is at risk:. Primary infection: children

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Experiment seven Mycobacterium tuberculosis

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  1. Experiment seven Mycobacterium tuberculosis

  2. Pathogenesis primary infection 1) lung infection secondary infection 2) Out lung infection

  3. Who is at risk: Primary infection: children Secondary infection: age>25

  4. M. tuberculosisGeneral Features

  5. Clinical syndromes a. fatigue, weakness, weight loss and fever b. pulmonary involvement: chronic cough,spit blood c. meningitis or urinary tract involvement d. bloodstream dissemination: miliary tuberculosis with lesions in many organs and a high mortality rate.

  6. MYCOBACTERIUM TUBERCULOSIS Can infect (disseminate) and cause disease in many different body locations such as: Meninges Brain Bone Kidney Essentially any organ (lung primary target)

  7. Diagnosis The steps to diagnose TB infection and disease include: • A medical evaluation that includes history and risk assessment • The tuberculin skin test • A chest x-ray • A bacteriological examination

  8. Treatment for Tuberculosis • Treated with a combination of multiple drugs for a long period of time: rifampin, isoniazid (INH), pyrazinamide, ethambutol, and streptomycin. • Emergence of multi-drug resistant M. tuberculosis strains.

  9. Principle While the majority of bacterial organisms are stainable by either simple or Gram-staining procedures, a few genera, particularly the members of the genus Mycobacterium like M tuberculosis, are resistant and can only be visualized by the acid fast method. The stain is of diagnostic value in identifying these organisms.

  10. Principle The characteristic difference between mycobacteria and other organisms is the presence of a thick waxy (lipoidal) wall that makes penetration by stains extremely difficult. Once the stain has penetrated, however, it cannot be readily removed even with the vigorous use of acid alcohol as a decolorizing agent. Because of this property, these organisms are called acid-fast, while all other microorganism, which are easily decolorized by acid alcohol, are non-acid-fast.The acid-fast stain use three different reagents as follows:

  11. Acid-fast stain 1.Prepare a Smear Smear Dry Fixed 2.Acid-fast stain

  12. Process of Acid-fast stain 5min 5min Washing 9% carbolfuchsinacid-alcohol (Primary staining)(Decoloration) Methylene blue (Conterstain) Washing 1-2min Washing dry the slide with bibulous papers Observation with the oil immersion lens Results :acid-fast bacteria:red color non-acid-fast:blue color

  13. Mycobacterium tuberculosis:red colour Shape:silm rod,o.4×3μm Background and the other bacteria:blue colour

  14. Corynebacterium diphtheriae

  15. Gray-black colonies on tellurite亚碲酸盐medium

  16. Gram stain • PROCEDURE: • Smear: size of a dime to form a thin film • Dry : air dry • Fix: through the warm air above the flame two or three times.

  17. washing 2min 30s Process of Neisser’sStain NEISSER’S STAIN Ⅰand Ⅱ NEISSER’S STAIN Ⅲ Blot dry with bibulous papers Observation with the oil immersion lens

  18. Metachromatic granules

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