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Flashcards in 6: Antibiotics Deck (57)
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1

What is the appropriate peak and trough level of Gentamicin?

  • Peak 6-10 ug/mL
  • Trough Less than 1 ug/mL

2

What is the main side effect of Carbapenems such as Meropenem or Imipenem?

Seizures

3

Which antibiotics are effective against Enterococcus?

  1. Vancomycin
  2. Timentin/Zosyn
  3. Ampicillin/Amoxicillin
  4. Genatmicin + Ampicillin

4

Which bacteria do Aminoglycosides (Gentamicin, Tobramycin) treat?

  • Gram negative rods
  • Pseudomonas, Acinetobacter, and Serratia
  • Not effective for anearobes
  • Synergistic with Ampicillin for Enterococcus (Beta-lactams facilitate aminoglycoside penetration)

 

[Resistance due to modifying enzymes leading to decreased active transport. Side effects: reversible nephrotoxicity, irreversible ototoxicitiy]

5

Which class of antibiotics functions as a PABA analogue and inhibits purine synthesis?

Sulfonamides

 

[sulfonamide functions by competitively inhibiting enzymatic reactions involving para-aminobenzoic acid (PABA). PABA is needed in enzymatic reactions that produce folic acid, which acts as a coenzyme in the synthesis of purines and pyrimidines. Mammals do not synthesize their own folic acid so are unaffected by PABA inhibitors, which selectively kill bacteria]

6

Which bacteria do third-generation cephalosporins (IE Ceftriaxone, Ceftazidime, and Cefotaxime) treat?

  • Gram negative rods (+/- anaerobic coverage)
  • Pseudomonas, Acinetobacter, and Serratia
  • Not effective for Enterococcus

 

[Side effects: cholestatic jaundice.  Ceftriaxone is associated with sludging in the gallbladder]

7

Which bacteria do Ticarcillin and Pipercillin treat?

  • Gram negative rods
  • Pseudomonas, Acinetobacter, and Serratia

 

[Side effects: they inhibit platelets]

8

What is the mechanism of action of Echinocandins such as Anidulafungin (Eraxis)?

It inhibits synthesis of cell wall glucan

 

[This is the go-to drug for candidemia]

9

What is the mechanism of resistance of methicillin-resistant Staph Aureus (MRSA)?

Mutation of cell wall-binding protein

10

What is the mechanism of bacterial resistance to Penicillin?

Plasmid carrying gene for beta-lactamase

11

Which bacteria does the Streptogramin: Synercid (Quinupristin/Dalfopristin) treat?

Gram positive cocci (Including MRSA and VRE)

12

Which 5 antibiotics or classes of antibiotics work by inhibiting cell wall synthesis?

  1. Penicillins
  2. Cephalosporins
  3. Carbapenems
  4. Monobactams
  5. Vancomycin

13

What are Iodophors like Betadine effective against?

  • Gram positive cocci
  • Gram negative rods

 

[Poor against fungi]

14

What is the mechanism of action of Amphotericin?

Binds sterols in the wall and alters membrane permeability

 

[This is the go-to drug for fungal sepsis other than candida and aspergillus. Side effects: nephrotoxic, fever, hypokalemia, hypotension, anemia. Liposomal type has fewer side effects.]

15

What is the mechanism of action of Voriconazole and Itraconazole?

They inhibit ergosterol synthesis, which is needed for the cell membrane

 

[Voriconazole is the go-to drug for invasive aspergillosis. Itraconazole is the go-to drug for a patient on prolonged broad-spectrum antibiotics.]

16

What is the frequency of dosing of Zosyn?

QID dosing

17

Which infections are treated with Acyclovir and which are treated with Ganciclovir?

  • Acyclovir: HSV, EBV
  • Ganciclovir: CMV

18

What is the mechanism of action of Acyclovir?

It inhibits viral DNA polymerase

 

[Used for HSV and EBV infections]

19

Which bacteria do first-generation cephalosporins (IE Cefazolin and Cephalexin) treat?

  • Gram positive cocci (Staph and Strep)
  • Not effective for enterococcus
  • Does not penetrate the CNS

 

[Ancef (Cefazolin) has the longest half-life, making it best for prophylaxis]

20

Which bacteria do Unasyn (Ampicillin/Sulbactam) and Augmentin (Amoxicillin/Clavulanic acid) specifically cover?

  • Gram positive cocci (staph and strep)
  • Gram negative rods
  • +/- anaerobic coverage
  • Enterococci

 

[Broad spectrum but is not effective for pseudomonas, acinetobacter, or serratia]

21

What is the side effect of Ethambutol?

Retrobulbar neuritis

22

Which 3 antibiotics or classes of antibiotics work by inhibiting the 50s ribosome and protein synthesis?

  1. Erythromycin
  2. Clindamycin
  3. Synercid

 

[Erythromycin is a macrolide. Synercid is a combination of Quinupristin and Dalfopristin, both of which are streptogramins]

23

Which class of antibiotic works by inhibiting DNA helicase (DNA gyrase)?

Quinolones

24

Which bacteria do second-generation cephalosporins (IE Cefoxitin, Cefotetan, and Cefuroxime) treat?

  • Gram positive cocci (less staph activity)
  • Gram negative rods (effective only for community-acquired GNRs)
  • +/- anaerobic coverage
  • Not effective for Enterococcus, Pseudomonas, Acinetobacter, or Serratia

 

[Cefotetan has longest half-life, making it best for prophylaxis]

25

Which bacteria do macrolides (Erythromycin) treat?

Gram positive cocci (best for community-acquired pneumonia and atypical pneumonias)

 

[Binds motilin receptor and is prokinetic for bowel. Side effects: Nausea, cholestasis]

26

What is the mechanism of action of Rifampin?

It inhibits RNA polymerase

 

[High rate of resistance. Side effects: hepatoxicity, GI symptoms]

27

Which bacteria does Tetracycline treat?

  • Gram positive cocci
  • Gram negative rods
  • Syphilis

 

[Side effects: tooth discoloration in children]

28

What is the mechanism of resistance of Vancomycin-resistant enterococcus (VRE)?

Mutation in cell-wall binding protein

29

Which 3 antibiotics or classes of antibiotics work by inhibiting the 30s ribosome and protein synthesis?

  1. Tetracycline
  2. Aminoglycosides (Tobramycin, Gentamicin)
  3. Linezolid

30

Which antibiotic works by producing oxygen radicals that breakup DNA?

Metronidazole (Flagyl)