Mycobacteria Flashcards
What factor seen in M. tuberculosis can lead to macrophage activation and TNF-alpha release?
Cord factor
Type of leprosy associated with Th2 predominance
Lepromatous = low cell mediated
Type of leprosy associated with high cell-mediated immunity
TH1 response = tuberculoid
Aside from mycolic acids, the high lipid content in M. tuberculosis cell wall is due to
Wax D
___ assay to check for M. tuberculosis drug resistance
Luciferase assay
What prevents phagosome-lysosomal fusion of M. tuberculosis?
exported repetitive protein (sulfatides)
What triggers cell-mediated immunity, delayed hypersensitivity reaction in M. tuberculosis
Tuberculin surface protein
In a M. tuberculosis granuloma, the central area is called
Langhan Giant Cells
surrounded by a zone of epitheloid cell
A positive PPD means that ___
- Current or active disease
- Past exposure but not necessarily active disease
- BCG vaccination
M. tb drugs that inhibit mycolic acid synthesis
Isoniazid
M. tb drug that inhibits arabinosyl transferase
Ethambutol
What interleukin mediates presentation of Mtb antigen by macrophage
IL-12
What CD4 level does Mycobacterium avium-intracellulare complex appear?
CD4 <50
M. leprae can be cultured in vitro in ____
- Mouse footpad
2. Armadillo
What are the reservoirs of M. lepae
- Humans
2. Armadillos
[Tuberculoid/Lepromatous]
few lesions little tissue destruction Few AFB in skin Present CMI Lepromin positive
Tuberculoid
[Tuberculoid/Lepromatous]
many lesions Marked tissue destruction Many AFB Can highly transmit CMI reduced Lepromin negative
Lepromatous
What are the nerves commonly affected in Hansen disease?
- Ulnar and median nerve damage - clawed hand
- Common peroneal: foot drop
- Posterior tibial - plantar insensitivity and clawed toes
______ seen in lepromatous form, tender nodules or humps on both shins
Erythema Nodusum Leprosum
Tx: Thalidomide
What is the DOC for tuberculoid leprosy
- Dapsone
2. Rifampin`
What is the DOC for lepromatous leprosy?
- Dapsone
- Rifampin
- Clofazimine
[Etiology]
broken jaw or dental extraction
PE: hard, non-tender with swelling sinus tracts draining sulfur granules
Actinomyces Israelii
Tx: Pen G and drainage
What stain is used to identify Nocardia asteroides?
Fite-faraco
[Etiology]
Aerobic, filamentous gram-positive rod with aerial hyphae
manifest as mycetomas and lung and brain abscess (orange colony)
Nocardiosis
Nocardia asteroides
Tx: TMP-SMX + drainage
What is the smallest free living organism?
Mycoplasma pneunoniae
can cause walking pneumonia
Tx: erythromycin or azithromycin
What is the culture media for M. pneumoniae
Eaton agent
Needs cholesterol and nucleic acid
What is the microscopic finding of M. pnuemoniae
- Fried egg appearance OR
2. Mulberry appearance
What causes the attachment and inhibits ciliary motion of M. pneumoniae?
TLR2 protein (P1 adhesin)