Mycobacterial

Question 1

M. tuberculosis

Answer 1

rod, lipid rich wall (mycolic acid), poor gram stain (Acid-Fast pink)
Intracellular - drugs must get inside cell
Slow growing; drug resistant is concern

Question 2

Latent TB

Answer 2

Inactive - contained tubercle bacilli in body
TST/blood test positive
normal CXR
negative sputum
No symptoms
Not infectious

Question 3

TB Disease

Answer 3

Active - multiplying tubercle bacilli in body
TST/blood test positive
abnormal CXR
positive sputum
Cough, fever, weight loss
Infectious before treatment

Question 4

Preferred Initial Therapy for active TB

Answer 4

Isoniazid, Rifampin, Pyrazinamide, Ethambutol

Question 5

Preferred Continuation Therapy for active TB

Answer 5

Isoniazid, Rifampin

Question 6

Latent TB therapy

Answer 6

Isoniazid

Question 7

MOA of Isoniazid

Answer 7

bactericidal for actively growing bacilli - penetrates into macrophages (intracellular/extracellular)
Inhibits synthesis of mycolic acid (cell wall) - forms bond with proteins in synthesis
Prodrug

Question 8

RES of Isoniazid

Answer 8

Mutation in Kat G = decreased activation
Overexpression of Inh A protein (mycolic acid synthesis)
Rapid resistance = 2 agents required to treat active

Question 9

AE Isoniazid

Answer 9

Hepatitis - increased with age and alcohol dependence

Peripheral neuropathy - structurally similar to vitamin B6 - reversed by low dose B6

Question 10

MOA Rifampin

Answer 10

Inhibits transcription - binds RNA polymerase

Penetrates tissue/phagocytic cells (intracellular)

Question 11

RES Rifampin

Answer 11

point mutation in bacterial RNA polymerase

Use in combination

Question 12

AE Rifampin

Answer 12

induces cytochrome p450 = increases elimination of drugs

Impacts metabolism of anti-retrovirals

Question 13

What to give HIV patient with TB?

Answer 13

Rifabutin instead of Rifampin

Question 14

MOA Pyrazinamide

Answer 14

Potential inhibitor of mycolic acid - dependent on acidic environment
Used ONLY in active TB
Prodrug

Question 15

RES Pyrazinamide

Answer 15

mutation in enzyme for activation

Question 16

AE Pyrazinamide

Answer 16

Hepatotoxicity, Hyperuricemia (gouty arthritis)

Question 17

MOA Ethambutol

Answer 17

inhibits arabinosyl transferase (cell wall)

only used in combination for active TB

Question 18

RES Ethambutol

Answer 18

point mutations in arabinosyl tranferase

Question 19

AE Ethambutol

Answer 19

retrobulbar neuritis (visual acuity loss)
Hyperuricemia

Question 20

MOA Streptomycin

Answer 20

Aminoglycoside - interfere with bacterial protein synthesis
Active against extracellular organisms - poor penetration
Only used in multi-drug resistant TB

Question 21

RES Streptomycin

Answer 21

point mutations in ribosomal proteins

Question 22

PKX Streptomycin

Answer 22

IV administration

poor penetration/distribution

Question 23

AE Streptomycin

Answer 23

ototoxic, vertigo

Question 24

MAC pulmonary infection treatment

Answer 24

Macrolide
Rifampin
Ethambutol
+/- Streptomycin

Question 25

MAC Dissemination treatment

Answer 25

Macrolide
Rifampin
Ethambutol

Question 26

MAC Prophylaxis (HIV)

Answer 26

Macrolide

Question 27

M. leprae treatment

Answer 27

Dapsone
Clofazimine
Rifampin

Question 28

MOA Dapsone

Answer 28

inhibit folic acid synthesis

Question 29

AE Dapsone

Answer 29

non-hemolytic anemia

hemolytic anemia in pts w/ G-6-P deficiency

Question 30

AE Clofazimine

Answer 30

Skin discoloration (red to black)