Mycobacteria Flashcards
How do mycobacteria appear upon staining?
Acid Fast: Acid fast rods
Gram: Gram Positive
T/F Mycobacterium are spore forming, aerobic, and slow growing
FALSE
Mycobacterium do NOT form spores, though they are aerobic and slow growing
What is the medium used to grow M. tuberculosis and other mycobacterium (except M. leprae)?
Lowenstein Jensen Medium
What property of mycobacterium make them resistant to dessication and antibiotic entrance?
Very strong cell wall with mycolic acid coating (“teflon”)
T/F: Asians, African Amerians and Hispanics/Latinos all have higher rates of TB than whites
TRUE
Asian: 29x higher
AA/Hispanics/Latinos: 8x higher
Primary tuberculosis is acquired via _____
Inhalation of droplet from an active case
Initial multiplication of primary TB is in the _____. It spreads through _____ to the _____.
Initial replication is in the alveolar macrophage
Spreads through lymphatic drainage to the hilar lymph nodes
An alveolar macrophage that has ingested M. tuberculosis is activated by _____ via interferon gamma.
TH1 cellular immune response
What happens when the TH1 cellular immune response successfully activates a macrophage containing MTB? If it is unsuccessful?
Successful activation: Disease arrested
Unsuccessful: Delayed type hypersensitivity injury and progression of disease
Reactivation TB typically begins in the _____ of the lung with _____ formation.
Upper lobes with granuloma formation
What are some of the hallmarks of TB?
Cough (usually w/mucus), hemoptysis, excessive sweating at night, fatigue, fever, unintentional weight loss (TNF-alpha mediated)
A _____ is swelling of a cervical lymph node due to the presence of TB that may be referred to as a “cold abscess.” It is not tender or warm, it is commonly seen in children, and may ulcerate.
Scrofula
The _____ test is a subdermal injection of purified MTB proteins. What designates a positive response?
PPD/Tuberculin Skin Test
Presence of a DTH response 2-3 days after injection indicates a positive PPD
The _____ test for TB measures levels of IFN-gamma produced by MTB antigen-specific T-cells
Quantiferon Gold test
What are the first line drugs used for TB infection?
RIPE Therapy
1) Rifampin
2) Isoniazid
3) Pyrazinomide
4) Ethambutol
5) Streptomycin
What are the seven second line MTB treatments?
1) Moxi- or Gatifloxacin
2) Ethionamide
3) Aminosalicylic acid
4) Cycloserine
5) Amikacin + Kanamycin
6) Capreomycin
7) Linezolid
The vaccine for TB is the _____, and is a _____ strain of M. bovis
Bacillus Calmette-Guerin (BCG) Vaccine
Live attenuated strain of M. bovis
What organism causes Leprosy/Hansen’s Disease?
Mycobacterium leprae
M. leprae has a predilection for what parts of the body?
Cooler regions (skin of extremities, mucous membranes, eyes, *peripheral nerves*)
A hallmark of M. leprae infection is the involvement of _____
Peripheral nerves
Leprosy presents with host dependent, non-healing lesions that have decreased _____
Sensation to touch/heat/pain (parathesis)
_____ leprosy is innocuous in terms of inflammatory cells. Acid fast bacteria are typically unable to be identified. Lesions are seen in lighter colored skin, and may be raised or reddish.
Indeterminate leprosy
_____ leprosy is the most localized form of leprosy that presents with one or few lesions that are well demarcated,circular, and slightly raised with central clearing. They are insensitive to heat and cold from damage to peripheral nerves.
Tuberculoid leprosy
Tuberculoid leprosy is associated with an intense _____ reaction; ____ organisms in the lesions; damage to _____ causing parathesia/anaesthesia
Tuberculoid leprosy:
Intense cell mediated reaction
Few organisms in lesions
Damage to peripheral nerves
_____ Leprosy preents with multiple lesions all ove rthe body that are homogenous in color and are more indurated.
Borderline Leprosy
_____ leprosy is characterized by unimpeded bacterial growth, with raised lesions all over the body, a lot of macrophages filled with M. leprae, and a “lion-like” face
What are the first line Anti-Leprosy drugs?
Rifampin, dapsone, clofazimine
What are the second line anti-leprosy drugs?
Minocycline, ofloxacin, clarithromycin
What species of mycobacterium is a water-borne contaminate that been seen in cases of Lasik surgery, tattoo ink and wound contamination?
M. chelonae
What species of mycobacterium has a similar gross pathology to sporotrichosis and forms “fish tank” granulomas
M. marinum
Infection with what species of mycobacterium presents as a steadily progressive, ulcerated lesion over 7 months?
M. ulcerans
