Mycobacteria

Question 1

Mycobacteriaceae oxygen requirements

Answer 1

Obligate aerobes

Question 2

Mycobacteriaceae spore formation

Answer 2

Non-sporeforming

Question 3

Mycobacteriaceae growth

Answer 3

Generally slow-growing

Question 4

Mycobacteriaceae acid-staining

Answer 4

Acid-fast and contain mycolic acid in cell walls

Question 5

Mycobacteriaceae pathogenesis

Answer 5

Facultative intracellular pathogens

Question 6

Tubercle bacilli strains of Mycobacteriaceae

Answer 6

1. Mycobacteriaceae tuberculosis
2. Mycobacteriaceae africanum
3. Mycobacteriaceae leprae
4. Mycobacteriaceae Boris

Question 7

Mycobacteriaceae microscopy

Answer 7

Cord growth (serpentine arrangement) of virulent strains

Question 8

How to identify Mycobacteriaceae

Answer 8

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

Question 9

Mycobacteriaceae tuberculosis colony morphology

Answer 9

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

Question 10

Mycobacteriaceae tuberculosis at-risk population

Answer 10

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

Question 11

Mycobacteriaceae tuberculosis transmission

Answer 11

Person to person aerosol (>1m)

Question 12

Mycobacteriaceae tuberculosis 3-virulence factors

Answer 12

1. Cord factor
2. Iron-capturing ability
3. Sulfolipids

Question 13

Mycobacteriaceae tuberculosis cord factor

Answer 13

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

Question 14

Mycobacteriaceae tuberculosis iron capturing ability

Answer 14

Required for the pathogen’s survival within phagocytes

Question 15

Mycobacteriaceae tuberculosis sulfolipids

Answer 15

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

Question 16

Mycobacteriaceae tuberculosis clinical entry

Answer 16

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

Question 17

Mycobacteriaceae tuberculosis infectious does

Answer 17

10 cells

Question 18

Mycobacteriaceae tuberculosis signs and symptoms

Answer 18

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

Question 19

Typical progression of pulmonary tuberculosis

Answer 19

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

Question 20

Mycobacteriaceae tuberculosis diagnostic criteria

Answer 20

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

Question 21

Mycobacteriaceae tuberculosis 4-drugs of treatment

Answer 21

Isoniazid (INH)
Rifampin
Para-aminoslicylic acid
Ethambutol

Question 22

Mycobacteriaceae tuberculosis control

Answer 22

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)

Question 23

Mycobacteriaceae leprae stain

Answer 23

Acid-fast bacilli

Question 24

Mycobacteriaceae leprae growth/ infection

Answer 24

Strict human pathogen, cannot be cultivated in-vitro

Question 25

Mycobacteriaceae leprae infectivity

Answer 25

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

Question 26

Mycobacteriaceae leprae risk-groups

Answer 26

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

Question 27

Mycobacteriaceae leprae initial signs and symptoms

Answer 27

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

Question 28

Four types of leprosy

Answer 28

1. Borderline tuberculoid leprosy 2. Borderline lepromatous leprosy 3. Tuberculoid leprosy 4. Lepromatous leprosy

Question 29

Borderline tuberculoid leprosy

Answer 29

Cutaneous lesions are numerous and not we’ll definite | Disease may regress, improve, or stay the same. May initially look like ring-worm

Question 30

Borderline lepromatous leprosy

Answer 30

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.

Question 31

Tuberculoid leprosy

Answer 31

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

Question 32

Lepromatous leprosy

Answer 32

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

Question 33

3 cardinal signs of leprosy

Answer 33

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)

Question 34

Lepromatous leprosy treatment

Answer 34

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

Question 35

Tuberculoid leprosy treatment

Answer 35

Dapsone + rifampicin (typically 6+ months to treat)

Question 36

mycobacterium Adium-intracellular complex (MAC)

Answer 36

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