上海交通大学：《医学微生物》课程教学资源（PPT课件讲稿）英文版 Mycobacterium

Mycobacterium

Mycobacterium

MYCOBACTERIUM THIS GENUS S 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

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) TYPE SPECIES: Mycobacterium tuberculosis

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

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 (∠ieh- Neelsen stain) o flood the slide with basic fuchsin(a red dye )in 5% phenol as a mordant o heat gently for few minutes to melt the wax e wash with 3% Hcl in ethanol o 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

Acid Fastness 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 Organisms that resemble M. tuberculosis, Causing a similar type of disease in humans) 1 tuberculosis 2 M bovis

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

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

M. tuberculosis 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

Mycabacterttn tuberculosis-Erdntan g COLONIAL MORPHOLOGY OF THE TUBERCULOSIS COMPLEX MYCOBACTERIA Resistance Not sensitive Sensitive Dry(highly) Wet Chemical disinfectants Heat(62-63C, 15min) (more) 3%HCL, 6%H2SO4, Alcohol (to nonspore 4%NaoH(15min) forming bacteria) Malachite EUGONIC GROWTH 14 DAYS DY SGONIC GROWTH 14 DAYS green(1:13000 Mycobacterium tuberculos is Mycobacterium bovis

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

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 Primary infection: children Secondary infection: age>25

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