Mycobacteria Flashcards

1
Q

Mycobacteriaceae oxygen requirements

A

Obligate aerobes

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2
Q

Mycobacteriaceae spore formation

A

Non-sporeforming

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3
Q

Mycobacteriaceae growth

A

Generally slow-growing

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4
Q

Mycobacteriaceae acid-staining

A

Acid-fast and contain mycolic acid in cell walls

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5
Q

Mycobacteriaceae pathogenesis

A

Facultative intracellular pathogens

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6
Q

Tubercle bacilli strains of Mycobacteriaceae

A
  1. Mycobacteriaceae tuberculosis
  2. Mycobacteriaceae africanum
  3. Mycobacteriaceae leprae
  4. Mycobacteriaceae Boris
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7
Q

Mycobacteriaceae microscopy

A

Cord growth (serpentine arrangement) of virulent strains

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8
Q

How to identify Mycobacteriaceae

A

Most labs will use PCR based methods (for most of these conditions CDC wants report on the results in 1-2 weeks max)

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9
Q

Mycobacteriaceae tuberculosis colony morphology

A

“Like grits on a baking sheet”: rough, dry, granular, ranging from non-pigmented to buff or tan colored colonies

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10
Q

Mycobacteriaceae tuberculosis at-risk population

A

Immunocompromised, malnourished, individuals exposed to sick people or healthy carriers

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11
Q

Mycobacteriaceae tuberculosis transmission

A

Person to person aerosol (>1m)

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12
Q

Mycobacteriaceae tuberculosis 3-virulence factors

A
  1. Cord factor
  2. Iron-capturing ability
  3. Sulfolipids
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13
Q

Mycobacteriaceae tuberculosis cord factor

A

Glycolipid responsible for serpentine growth pattern: toxic to leukocytes, activates macrophages and dendritic cells, plays a role in the development of the granulomatous lesions

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14
Q

Mycobacteriaceae tuberculosis iron capturing ability

A

Required for the pathogen’s survival within phagocytes

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15
Q

Mycobacteriaceae tuberculosis sulfolipids

A

Prevents the fusion of the phagosome to the lysosome, so organism is not exposed to lysosomal enzymes and enables it to live within a cell

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16
Q

Mycobacteriaceae tuberculosis clinical entry

A

Inhalation (most common), ingestion, via the mucosa of the genital-urinary tract or conjunctiva, or via skin abrasions
- disease mostly due to host immune response

17
Q

Mycobacteriaceae tuberculosis infectious does

A

10 cells

18
Q

Mycobacteriaceae tuberculosis signs and symptoms

A

Fatigue, fever, unexplained weight loss, night sweats (soaking through all your bedding type sweats)
Pulmonary TB: productive cough longer than 3 weeks w/ hemoptysis (coughing up blood) and chest pain
Extrapulmonary TB: (liver and spleen most common) will vary based on location but jaundice is common

19
Q

Typical progression of pulmonary tuberculosis

A

Pneumonia (inflammation
Granuloma (tubercule) formation with fibrosis
Caseous necrosis (breaks down)
Cavity formation— center liquefies and empties into bronchi. Bacteria escapes

20
Q

Mycobacteriaceae tuberculosis diagnostic criteria

A
  1. Mantoux test (tuberculin skin test) using purified protein derivatives (delayed hypersensitivity rxn indicates previous or current infection, OR VACCINATION)
  2. Chest X-ray to look for granuloma
  3. Sputum for AFB
  4. PCR/ culture for direct evidence of active disease
21
Q

Mycobacteriaceae tuberculosis 4-drugs of treatment

A

Isoniazid (INH)
Rifampin
Para-aminoslicylic acid
Ethambutol

22
Q

Mycobacteriaceae tuberculosis control

A

Vaccination (more common in areas with bovis infections
Prophylactic and therapeutic intervention for all those possibly exposed after someone is diagnosed
Careful case and treatment monitoring (you are regulated to make sure you take ALL of the meds ON TIME, EVERY DAY)

23
Q

Mycobacteriaceae leprae stain

A

Acid-fast bacilli

24
Q

Mycobacteriaceae leprae growth/ infection

A

Strict human pathogen, cannot be cultivated in-vitro

25
Q

Mycobacteriaceae leprae infectivity

A

Infectivity is very low- prolonged contact is required.
Disease state is primarily due to host immune response
Incubation period can last from several months to 20-30 years

26
Q

Mycobacteriaceae leprae risk-groups

A

Those who live in tropical settings, and/or those that live in close contact with patients who have untreated, active, predominately multibacillary leprosy, and people living in countries with endemic leprosy

27
Q

Mycobacteriaceae leprae initial signs and symptoms

A

Symptoms initially mild- not recognized until cutaneous eruption presents. First, numbness, then inability to sense temperature, then inability to sense pressure, then ability to sense pain, then ability to sense even deep pressure (puncture)
Will notice a hypopigmented (very pale) macule (lesion)
From this stage will develop into the different types

28
Q

Four types of leprosy

A
  1. Borderline tuberculoid leprosy
  2. Borderline lepromatous leprosy
  3. Tuberculoid leprosy
  4. Lepromatous leprosy
29
Q

Borderline tuberculoid leprosy

A

Cutaneous lesions are numerous and not we’ll definite

Disease may regress, improve, or stay the same. May initially look like ring-worm

30
Q

Borderline lepromatous leprosy

A

Numerous macule-type lesions, as well as papules, plaques, and nodules. Inverted-saucer lesions common. May still have feeling- anesthesia often absent. Disease may remain in this stage, improve or regress.

31
Q

Tuberculoid leprosy

A

Strong, cell-mediated response to M. Leprae antigens
Lesions don’t contain many mycobacterium (no AFB on skin test)
Extensive plaques on trunk, face, and limbs
Nerves often thicken and lose function. LEPROMIN TEST WILL BE POSITIVE. Can progress into lepromatous type if left untreated for long time

32
Q

Lepromatous leprosy

A

Disfiguring- lesions are large, diffuse, and granulomatus. If nodules are bad enough, may lose parts of the face and digits.
Weak or no cell-mediated responses to antigens, and skin test will contain large bacteria counts (M. Leprae)
LEPROMIN test will not respond (NEGATIVE)
This is the infectious form of leprosy

33
Q

3 cardinal signs of leprosy

A
  1. One or more hypo-pigmented, anesthetic skin patches
  2. One or more thickened peripheral nerves
  3. A positive skin smear (microscopy w/ acid-fast stain)
34
Q

Lepromatous leprosy treatment

A

Dapsone + rifampicin + clofazimine (typically takes 12+ months to treat)

35
Q

Tuberculoid leprosy treatment

A

Dapsone + rifampicin (typically 6+ months to treat)

36
Q

mycobacterium Adium-intracellular complex (MAC)

A

Opportunistic ubiquitous pathogen attacking in immunocompromised persons (frequently with AIDS). Produces a tuberculosis or leprosy-like disease (often disseminated in AIDS patients) that is highly resistant to anti-tuberculosis drugs. Requires LONG combination treatment