Bacteria: Mycobacteria Flashcards
List the 2 Mycobacterium
- Mycobacterium Tuberculosis
2. Mycobacterium Leprae
Mycobacterium tuberculosis
- acid-fast bacterium
- Mycobacterium
- obligate aerobes
Mycobacterium tuberculosis bacteria stain acid-fast due to
high mycolic acid content in the cell membrane
carbol fuchsin is
a dye used to detect acid-fast bacteria, such as Mycobacterium tuberculosis
____________ _________ ________ is a growth medium used to culture Mycobacterium tuberculosis
Lowenstein-Jensen Agar
Mycobacterium tuberculosis bacteria replicate within
Macrophages
Cord Factor
cord factor produced by Mycobacterium tuberculosis is a membrane glycolipid responsible for clumping of bacterial cells into serpentine cords in vitro and for protection of bacteria against host defenses in vivo (strains that lack cord factor are not virulent)
Sulfatides
sulfatides produced by Mycobacterium tuberculosis are sulfolipids that prevent phagolysosome fusion (protecting bacterial cells from exposure to lysosomal hydrolases, allowing for intracellular survival)
Primary tuberculosis typically affects
the middle or lower lobes of the lungs
Lymphatic dissemination of Mycobacterium tuberculosis during primary tuberculosis can result in
hilar lymphadenopathy
A Ghon complex is
lung lesion that usually affects the middle or lower lobe of the lung consisting of hilar lymphadenopathy and a parenchymal granuloma
A ________ ______ can form during primary tuberculosis
Gohn Complex
The caseating granulomas of primary tuberculosis are
characterized by a central necrotic zone (necrotic macrophages and cellular debris) walled off by macrophages and lymphocytes
Latent tuberculosis infections occur
when dormant Mycobacterium tuberculosis bacteria are contained within walled-off foci
Primary tuberculosis usually resolves by
fibrosis of lung tissue (granulomas form to wall off Mycobacterium tuberculosis)
The purified protein derivative (PPD) skin test (or tuberculin skin test (TST)) involves
intradermal injection of Mycobacterium tuberculosis antigen; an induration >15 mm (in immunocompetent patients who are low-risk of exposure) at 48 to 72 hours is considered a positive result
The bacille Calmette-Guerin (BCG) vaccine for tuberculosis
may cause a false-positive reaction to the purified protein derivative/tuberculin skin test
Miliary Tuberculosis
- miliary tuberculosis occurs when the immune system fails to clear the infection, resulting in diffuse hematogenous dissemination of tuberculosis to multiple organs
- Potentially fatal infection
Reactivation of latent tuberculosis is associated with use of
TNF-alpha inhibitors
TNF alpha is important for
granuloma formation and maintenance
Reactivation (secondary) tuberculosis
- typically affects the upper lobes of the lungs
2. may present with cough hemoptysis and night sweats
Pott disease
is an infection of the vertebral column (usually affecting the lower thoracic and upper lumbar region) that results from dissemination of Mycobacterium tuberculosis from other sites (Pott disease can result from progressive primary or reactivation (secondary) tuberculosis)
Progressive primary tuberculosis or reactivation (secondary) tuberculosis can
disseminate to the CNS and cause cavitary lesions and tuberculomas in the brain
Treatment for tuberculosis
- the combination of rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) is administered for (typically symptomatic) tuberculosis to combat and further prevent drug-resistant strains
- rifampin and isoniazid can be used in cases of latent tuberculosis to prevent reactivation
