Mycobacterium Flashcards
Mycobacteria include 2 species that almost every one has heard of:
Mycobacterium Tuberculosis
Mycobacterium Leprae
Causes tuberculosis
Mycobacterium Tuberculosis
Causes leprosy
Mycobacterium Leprae
These organism are thin rods with lipid-laden cell walls.
Mycobacteria
Only Mycobacteria and Nocardia are _______.
Acid-fast
An obligate aerobe, which makes sense as it most commonly infects the lungs, where oxygen is abundant.
Acid-fast bacillus
Mycobacterium tuberculosis grows very slowly, taking up to ______ for visible growth.
6 weeks
There is one class of lipid that only acid-fast organisms have and that is involved in mycobacterial virulence-mycosides. The terminology is as follows:
Mycolic acid Mycoside Cord factor Sulfatides Wax D
A large fatty acid. The chemical structure of mycolic acid, which is a large fatty acid.
Mycolic acid
A mycolic acid bound to a carbohydrate, forming a glycolipid.
Mycoside
A mycoside formed by the union of 3 mycolic acids with a disaccharide.
Cord factor
Cord factor mycoside is only found in virulent strains of _______________.
Mycobaterium tuberculosis
Mycosides that resemble cord factor with sulfates attached to the disaccharide. They inhibit the phagosome from fusing with the lysosome that contains bacteriocidal enzymes.
Sulfatides
A complicated mycosides that acts as an adjuvant ( enhances antibody formation to an antigen) and may be the part of Mycobacterium tuberculosis that activates the protective cellular immune system.
Wax D
Affects the lung but can also cause disease in almost any other tissue.
Mycobaterium tuberculosis
It spreads and damages the body depends on the host’s immune response. The organism and the immune system interact as follows:
Facultative intracellular growth
Cell-mediated immunity
Mycobacterium Test
PPD skin test
Some of the macrophages succeed in phagocytosing and breaking up the invading bacteria.
These macrophages then run toward a local lymph node and present parts of the bacteria to T- helper cells.
Cell-mediated immunity
Intradermal injection of antigenic protein particles from killed Mycobacterium tuberculosis.
PPD (Purified Protein Derivative)
The test is positive at 5 mm of induration in patients who are immunocompromised, such as those with aids.
PPD SKIN TEST
First exposure to Mycobacterium tuberculosis called _______ and usually is a subclinical (asymptomatic) lung infection.
Primary Tuberculosis
These defeated bacteria lie dormant but can later rise up and cause disease. This second infection is called _________.
Secondary or reactivation tuberculosis
Mycobacterium tuberculosis is usually transmitted.
Aerosolized Droplet Nuclei
Tuberculosis is a confusing disease because so many different things can happen. As cell mediated immunity develops.
- The infection can be contained so that the patient will not even realize he was infected.
- It can become a symptomatic disease.
This vaccine is debatably effective in preventing tuberculosis but it causes a positive PPD.
BCG ( Bacilus Calmette-Guerin)
A calcified tubercle in the middle or lower lung zone.
Ghon focus
A ghon focus accompanied by perihilar lymph node calcified granulomas.
Ghon or Ranke, complex.