RAPID GROWERS Visible colonies in 5 days SLOW GROWERS Visible colonies in 5 tuberculosis cells grow either as discrete rods or as aggregates.

MYCOBACTERIUM MYCOBACTERIUM MYCOBACTERIUM MYCOBACTERIUM THIS GENUS IS COMPOSED OF: Strictly aerobic, acid-fast rods, does not Stain well gram stain indeterminant, DNA has high g+c content, unique cell wall, Mycolic acid carbon chain length c60 Relatively slow growth two groups

A. RAPID GROWERS Visible colonies in 5 days

B. SLOW GROWERS Visible colonies in 5

days TYPE SPECIES: Mycobacterium tuberculosis THE GENUS MYCOBACTERIUM CAN BE DIVIDED INTO FOUR BROAD GROUPS THE GENUS MYCOBACTERIUM CAN BE DIVIDED INTO FOUR BROAD GROUPS

1. THE TUBERCULOSIS COMPLEX

2. SLOW GROWING MYCOBACTERIA OTHER THAN TUBERCULOSIS MOTT

3. RAPIDLY GROWING MYCOBACTERIA

4. MYCOBACTERIUM LEPRAE

Acid Fastness Stain Acid Fastness Stain Ziehl-Neelsen stain Ziehl-Neelsen stain  flood the slide with basic fuchsin a red dye in 5 phenol as a mordant.  heat gently for few minutes to melt the wax.  wash with 3 HCl in ethanol.  counter-stain with methylene blue. Mycobacterium stains red and other bacteria and the background are blue. The mycolic acid and its derivatives are responsible for the acid f THE TUBERCULOSIS COMPLEX THE TUBERCULOSIS COMPLEX Organisms that resemble M. tuberculosis; Causing a similar type of disease in humans

1. M. tuberculosis 2. M. bovis

Mycobacterium tuberculosis Mycobacterium tuberculosis General Features General Features  It is a causative agent for human tuberculosis.  It grows very slow with a generation time of 12-15 hours.  On solid media the colonies are raised and rough with a wrinkled surface . 

M. tuberculosis cells grow either as discrete rods or as aggregates.

Virulent strains tend to grow as an aggregated long arrangement called serpentine cord. Cord factor is a derivative of mycolic acids, trehalose 6-dimycolate. Resistance Resistance : : UV Malachite green1:13000 Alcohol to nonspore- forming bacteria 3HCL, 6H 2 SO 4 , 4NaOH 15min Heat62-63 ℃,15min Chemical disinfectants more Wet Dry highly Sensitive Not sensitive EUGONIC GROWTH 14 DAYS DYSGONIC GROWTH 14 DAYS Mycobacterium tuberculosis Mycobacterium bovis COLONIAL MORPHOLOGY OF THE TUBERCULOSIS COMPLEX MYCOBACTERIA COLONIAL MORPHOLOGY OF THE COLONIAL MORPHOLOGY OF THE TUBERCULOSIS COMPLEX MYCOBACTERIA TUBERCULOSIS COMPLEX MYCOBACTERIA Transmission Transmission Through respiratory tract, alimentary tract, injured skin 。 TB in the lungs or throat can be infectious. This means that the bacteria can be spread to other people. TB in other parts of the body, such as the kidney or spine, is usually not infectious. Who is at risk: Who is at risk: Primary infection: children Secondary infection: age25 Virulence factors Virulence factors No spore, no flagellum, no exotoxin,no endotoxin, no invasive enzyme Capsule: polysaccharide;CR3;enzyme; protect LipidLipo arabinomannan Heat-shock proteinTuberculin protein: antigenicity, old tuberculin; associate with wax D can cause hypersensitivity and form tubercle Lipid: closely related to virulence a. Phospholipid monocytes proliferate,cause tubercles

b. Wax D adjuventnot only to TB, delayed-type

hypersensitivity c. Sulfatide 硫酸脑苷脂 suppress phagosome combine with lysosome

d. Cord factor

trehalose-6,6-dimycolate destroy mitochondria, cause chronic granulomatosis, suppress WBC wandering Pathogenesis Pathogenesis primary infection 1 lung infection secondary infection 2 Out lung infection Clinical syndromes 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 . Primary Tuberculosis Primary Tuberculosis  The organisms are transmitted among human via aerosol.  TB bacilli lodge in the alveoli or lung alveolar ducts and most of bacilli are phagocytosed by alveolar macrophages.  Macrophages migrate to the hylar lymph node and generate T cell-mediated immune response. can be monitored by tuberculin test Tuberculin Skin Test Tuberculin Skin Test  Tuberculin is a mixture known as purified protein derivatives PPD from TB bacilli.  It is a test for delayed type hypersensitivity. Positive reaction, reddening and thickening 5mm at the site of injection after 2-3 days , indicates cellular immunity to tubercle bacilli.  Macrophages containing TB bacilli clump together and begin to form tubercles. granulomatous response  With time, the centers of the tubercles become necrotic and form cheesy acellular masses of caseous materials. caseous lesion Symptoms: Activation of macrophages - cytokine secretion, IL-1: fever, TNF: lipid metabolism, weight loss, tissue necrosis. Oxygen radicals: tissue damages Tissue necrosis - inflammation - mucous secretion, destruction of blood vessels - frequent cough and bloody sputum PULMONARY TUBERCULOSIS PULMONARY TUBERCULOSIS Large caseating tubercle Miliary tubercles HUMAN LUNG HUMAN LUNG HUMAN LUNG HUMAN LUNG TUBERCULOSIS TUBERCULOSIS MYCOBACTERIUM TUBERCULOSIS MYCOBACTERIUM TUBERCULOSIS Can infect disseminate and cause disease in many different body locations such as: 1. Meninges 2. Brain 3. Bone 4. Kidney 5. Essentially any organ lung primary target Bacteria coughed up in sputum Inhalation of bacteria Bacteria reach lungs, enter macrophages Bacteria reproduce in macrophages Lesion begins to form caseous necrosis Activated macrophages Bacteria cease to grow; lesion calcifies Immune suppression Reactivation Lesion liquefies Dead phagocytes, necrosis

M. tuberculosis