Lecture 3 Part 4: Mycobacteria Flashcards
What type of bacteria is Mycobacterium tuberculosis?
Obligate aerobic, slow-growing, Gram-positive bacilli
What shape does Mycobacterium tuberculosis have?
Thin, club-shaped bacilli
Is Mycobacterium tuberculosis motile or spore-forming?
Non-motile, non-spore forming
Is Mycobacterium tuberculosis a toxin-producing bacterium?
no girlieee its non-toxin forming
Mycobacterium tuberculosis has a capsule?
naurrr its UNencapsulated
What component is responsible for Mycobacterium tuberculosis’s resistance to disinfectants and detergents?
Its lipid-rich cell wall (waxy coat)
What percentage of Mycobacterium tuberculosis’s cell wall is lipid?
60% lipid, 15% transport proteins and porin
What are the key components of the cell wall of Mycobacterium tuberculosis?
Mycolic acid and lipoarabinomannan (LAM).
True or False
LAM is specfic to mycobatrium
TRUE
What is the natural reservoir for Mycobacterium tuberculosis?
humans only
How is Mycobacterium tuberculosis primarily transmitted?
through respritatory droplets and direct contact (highly infecious)
What is used for testing for Mycobacterium tuberculosis?
Purified Protein Derivatives (PPDs).
What is notable about the DNA of Mycobacterium tuberculosis?
it has a high G/C content
(G/C means guanine (G) and cytosine (C) bases.)
How is Mycobacterium tuberculosis primarily transmitted?
Through inhalation of aerosols (tiny droplets) from an infected person.
What cells does Mycobacterium tuberculosis colonize in the lungs?
alveolar macrophages
How does Mycobacterium tuberculosis avoid being destroyed by macrophages?
it blocks the fusion of phagosomes (vesicles containing the bacteria) with lysosomes (vesicles containing digestive enzymes).
What is the body’s response to macrophages infected with Mycobacterium tuberculosis?
localized inflammation in the lungs
Where does Mycobacterium tuberculosis replicate?
intracellularly
(in other words inside the macrophage)
What determines the clinical disease caused by Mycobacterium tuberculosis?
The initial amount of bacteria (inoculum) that enters the body (primary infection)
What can happen to Mycobacterium tuberculosis during a primary infection?
It can either be eliminated by the immune system or persist in the body
What structure does Mycobacterium tuberculosis form in the body?
Large necrotic granulomas surrounded by fibrin
How long can Mycobacterium tuberculosis persist in the body?
it can persist for years, kept in check by the immune system
When does active disease from Mycobacterium tuberculosis typically manifest?
With increasing age or immunosuppression (secondary infection)
Where is Mycobacterium tuberculosis commonly localized, and can it spread?
It is commonly localized to the lungs but can disseminate to other parts of the body
Name 4 basic characteristics of Mycobacterium leprae?
- weakly Gram-positive
- strongly acid-fast rods
- slow growth
- long incubation period
How is Mycobacterium leprae transmitted?
through aerosols or skin contact
Where does Mycobacterium leprae replicate?
inside macrophages
What are the two types of leprosy caused by Mycobacterium leprae?
- tuberculoid leprosy
- lepromatous leprosy
Describe tuberculoid leprosy
it is self-limiting and involves a vigorous immune response
What are the 5 key characteristics of lepromatous leprosy?
- Disfiguring lesions
- Extensive tissue damage
- Highly infectious
- Defective cellular immune response
- Hypergammaglobulinemia
