FA - Micro - Antimicrobials (2016) Flashcards Preview

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Flashcards in FA - Micro - Antimicrobials (2016) Deck (47):
1

Carbapenems - Mechanism of imipenem:

1. Broad-spectrum, β-lactamase-resistant carbapenem.
2. ALWAYS administered with cilastatin (inhibitor of renal dihydropeptidase I) to DECREASE inactivation of drug in renal tubules.

2

Newer carbapenems include:

1. Ertapenem --> LIMITED PSEUDOMONAS coverage.
2. Doripenem.

3

Carbapenems - Clinical use:

1. Gram (+) cocci.
2. Gram (-) rods.
3. Anaerobes.

4

Carbapenems - Clinical use limited to ...?

Life-threatening infections or after other drugs have failed.
--> Significant side effects.

5

Meropenem has ...?

Decr. risk for SEIZURES and is STABLE to dehydropeptidase I.

6

Carbapenems - Adverse effects:

1. GI distress.
2. Skin rash.
3. CNS toxicity (seizures).
At high plasma levels.

7

Vancomycin - Mechanism:

Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors.

8

Vancomycin - Bacteriostatic/cidal?

Bactericidal against MOST bacteria.
--> Bacteriostatic against C.difficile.
--> Not susceptible to beta-lactamases.

9

Vancomycin - Clinical use:

Gram (+) bugs ONLY --> Serious multidrug-resistant organisms, including:
1. MRSA.
2. S.epidermidis.
3. Sensitive Enterococcus species.
4. C.difficile (ORAL dose).

10

Vancomycin - Adverse effects:

1. Well tolerated in general - But NOT trouble free.
2. Nephrotoxicity.
3. Ototoxicity.
4. Thrombophlebitis.
5. Diffuse flushing - Red man syndrome (pretreat with antihistamines + slow infusion rate).

11

Vancomycin - Mechanism of resistance:

Occurs in bacteria via amino acid modification of D-ala D-ala to D-ala D-lac.

12

Oxazolidinones:

Linezolid.

13

Linezolid - Mechanism:

1. Inhibits protein synthesis by binding to 50S.
2. Prevents formation of the initiation complex.

14

Linezolid - Clinical use:

Gram (+) species including MRSA + VRE.

15

Linezolid - Adverse effects:

1. Bone marrow suppression (esp. thrombocytopenia).
2. Peripheral neuropathy.
3. Serotonin syndrome.

16

Linezolid - Mechanism of resistance:

Point mutation of ribosomal RNA.

17

Dapsone - Mechanism:

Similar to sulfonamides, but structurally distinct agent.

18

Dapsone - Clinical use:

1. Leprosy (lepromatous and tuberculoid).
2. PCP proph.

19

Dapsone - Side effects:

Hemolysis if G6PD deficient.

20

Daptomycin - Mechanism:

LIPOPEPTIDE that disrupts cell membrane of gram (+) cocci.

21

Daptomycin - Clinical use:

1. S.aureus skin infections (esp. MRSA).
2. Bacteremia.
3. Endocarditis.
4. VRE.

22

Daptomycin - Side effects:

1. Myopathy.
2. Rhabdomyolysis.

23

Daptomycin - NOT used for ...?

PNEUMONIA!!!
AVIDLY BINDS AND INACTIVATES SURFACTANT!!!

24

Rifamycins - Mechanism of resistance:

Mutations reduce drug binding to RNA polymerase.
--> Monotherapy rapidly leads to resistance.

25

Streptomycin - Mechanism:

Interferes with 30S.

26

Streptomycin - Clinical use:

Mycobacterium tuberculosis (2nd line).

27

Streptomycin - Adverse effects:

1. Tinnitus.
2. Vertigo.
3. Ataxia.
4. Nephrotoxicity.

28

Treatment of highly-resistant bacteria - Multidrug-resistant P.aeruginosa, multidrug-resistant Acinetobacter baumannii:

1. Polymyxin B.
2. Polymyxin E (colistin).

29

Azoles inhibit which CYP450 enzyme involved in ergosterol synthesis?

14-alpha-demethylase.

30

Anti-mite/louse therapy:

1. Permethrin (blocks Na channels --> Neurotoxicity).
2. Malathion (AChE inhibitor).
3. Lindane (Blocks GABA --> Neurotoxicity).
--> Used to treat scabies (Sarcoptes scabiei) + Lice (Pediculus and Pthirus).

31

Hep C therapy:

1. Ribavirin.
2. Sofosbuvir.
3. Simeprevir.

32

Sofosbuvir - Mechanism:

Inhibits HCV RNA-dependent RNA polymerase --> Acts as a chain terminator.

33

Sofosbuvir - Clinical use:

1. Chronic HCV in combination with ribavirin, +/- Peg-IFN.
2. DO NOT use as MONOTHERAPY.

34

Sofosbuvir - Adverse effects:

1. Fatigue.
2. Headache.
3. Nausea.

35

Simeprevir - Clinical use:

1. Chronic HCV in combination with LEDIPASVIR.
2. DO NOT USE AS MONOTHERAPY.

36

Simeprevir - Adverse effects:

1. Photosensitivity.
2. Rash.

37

Ledipasvir:

NS5A INHIBITOR.

38

5 infection control techniques:

1. Autoclave.
2. Alcohols.
3. Chlorhexidine.
4. Hydrogen peroxide.
5. Iodine and iodophors.

39

Infection control techniques - Goals include:

1. Disinfection.
2. Sterilization.

40

Disinfection:

Reduction of pathogenic organism counts to safe levels.

41

Sterilization:

Inactivation of self-propagating biological entities.

42

Autoclave:

Pressurized steam at >120C - May be sporicidal.

43

Alcohols:

Denature proteins and disrupt cell membranes. Not sporicidal.

44

Chlorhexidine:

Denatures proteins and disrupts cell membranes. NOT sporicidal.

45

Hydrogen peroxide:

Free radical oxidation - Sporicidal.

46

Iodine and iodophors:

Halogenation of DNA, RNA, and proteins - May be sporicidal.

47

Cephalosporins (I-V) - Mechanism of resistance:

Structural change in penicillin-binding proteins (transpeptidases).