Quiz 5 - TB, Leprosy, And Diarrhea Flashcards
Tell me about mycobacterium.
Aerobic, acid-fast bacilli
*Almost impermeable hydrophobic cell wall of mycolic acid and lipids
**Hard for antimicrobials to do their job
***Efflux pumps to pump harmful stuff out, and some spp. Can hide inside pts cells
What two key diseases does mycobacterium cause?
Mycobacterium tuberculosis
— 9 million new cases and 2 million deaths annually worldwide
Mycobacterium leprae - Hansen’s Disease
— >2 million new cases worldwide
T/F - Bacteria grow better in areas with cooler body temps closer to skin surface.
TRUE
Primary TB - Latent or Asymptomatic - prophylactic treatment of choice?
Isoniazid for 9 months
Primary TB - Overt/Active - Tx of choice?
“2 with 4, then 4 with 2”
2 months with Rifampin, Isoniazid, Pyrazinamide, Ethambutol
—RIPE
—**Only take Pyrazinamide for up to 2 months. It can be hepatotoxic
Follow with 4 months with Rifampin and Isoniazid
—RI
Secondary TB is at greatest risk for what populations?
HIV+
Immunosuppressed
High risk
What is the rule of 5s?
Pts with mycobacterium TB have a 5% risk in the first 2 years and a 5% lifetime risk
**Pts with HIV have a 5+5% risk of reactivation PER YEAR
What is the tx of choice for secondary TB?
“2 with 5, then 4 with 2”
2 months with combination of Rifampin, Isoniazid, Pyrazinamide, Ethambutol, and STREPTOMYCIN
-RIPES
Follow with 4 months of just Isoniazid and rifampin.
Streptomycin is what?
Azithromycin is what?
Rifampin is what?
Strep - Aminoglycoside - 30S ribosomal inhibitor
Azithromycin - Macrolide - 50S ribosomal inhibitor
Rifampin - Nucleic acid synthesis inhibitor
What drug is the choice for prophylaxis of active TB?
Isoniazid
What is Isoniazid’s mechanism?
Decrease mycolic acid synthesis
-Must be activated by the bacterial enzyme Kat G, which is a TB catalase oxidase enzyme
—This produces free radicals
What are some adverse effects of Isoniazid?
Hepatotoxicity
Can cause a pyridoxine deficiency
—ALWAYS ADMINISTER WITH VITAMIN B6 TO MAINTAIN HEME SYNTHESIS AND PREVENT NEUROTOXICITY
*Also, pts need to avoid alcohol during and before/after intake
T/F - Pyrazinamide is a prodrug.
TRUE
When is Pyrazinamide used?
ACTIVE TB infection
What is Pyrazinamide’s mechanism?
Inhibits mycolic acid synthesis
Req’s acidic pH to be activated
*It is an essential part of the tx of TB meningitis
**Crosses the BBB
What are effects of Pyrazinamide?
HEPATOTOXICITY
Can cause gout or make it worse (increases uric acid)
*CONTRAINDICATED IN PREGNANCY
When is ethambutal used?
Tx of ACTIVE myco TB infection
What is ethambutal’s mechanism?
Decreases polymerization of cell wall by inhibiting arbinosal transferase
Crosses the BBB
What are some effects of ethambutal?
Ocular toxicity
Color blindness
Ocular neuritis -> blindness
What is Bedaquiline?
Used for MULTI-DRUG RESISTANT TB
Inhibits the mycobacterium ATP synthase
Causes prolonged QT syndrome
Tuberculoid vs lepromatous leprosies?
Tuberculoid - Well-demarcated - good immune response
Lepromatous - Poorly demarcated - Poor immune response
What is the drug of choice for TB/Leprosy? What about prophylaxis?
Rifampin
Dapsone
Tell me about Dapsone.
Mech: competes with PABA to inhibit bacterial dihydrofolate synthesis
Use: Prophylaxis for leprosy and pneumocystis jiroveci
Effects: Hepatoxicity, hemolysis, CROSS SENSITIVITY IF ALLERGIC TO SULFONAMIDES
What bug causes Traveller’s diarrhea? And what is used to treat it?
E. coli
Rifaximin
*Sometimes can be from campylobacter jejuni, shigella, or salmonella.
—Use of ciprofloxacin is effective
What is used against C diff?
Metronidazole
