Antibiotics II: Inhibitors of Cell Wall Synthesis

Question 1

Beta-lactams: bactericidal or bacteriostatic?

Answer 1

bactericidal

Question 2

Beta-lactams: time-dependent or concentration-dependent?

Answer 2

time-dependent

Question 3

Mechanism of cell wall disruption by beta-lactams?

Answer 3

irreversibly inhibits transpeptidase; most effective in log phase of growth; target PBPs (penicillin-binding proteins)

Question 4

G+ mechanism of resistance

Answer 4

secretion of beta-lactamases

Question 5

standard, narrow-spectrum

Answer 5

Penicillin G, Penicillin V

Question 6

Targets of penicillin

Answer 6

G+»>G-; anaerobic bacteria

Question 7

DOC for syphilis

Answer 7

penicillin G

Question 8

Penicillinase-resistant, narrow spectrum

Answer 8

Nafcillin

Question 9

Use for Nafcillin

Answer 9

Pen G-resistant staph (MSSA) endocarditis, SSTIs (no G- activity)

Question 10

Aminopenicillins, broad-spectrum

Answer 10

Amoxicillin

Question 11

MOA for amoxicillin

Answer 11

activity against G- bacteria due to increased penetration through porins

Question 12

Major use of amoxicillin

Answer 12

URIs

Question 13

Antipseudomonal, extended-spectrum

Answer 13

ticarcillin, piperacillin

Question 14

DOC for nosocomial G- infections

Answer 14

ticarcillin, piperacillin

Question 15

beta-lactamase inhibitor

Answer 15

clavulanic acid

Question 16

half-life of beta-lactams

Answer 16

short (30-90 min)

Question 17

single dose repository prep given IM used for syphilis and prevention of rheumatic fever

Answer 17

pen G benzathine

Question 18

Reaction common during therapy for syphilis

Answer 18

Jarish-Herxheimer (inflammatory response after lysis of organism)

Question 19

large IV doses cause sodium overload –> CHF

Answer 19

ticarcillin

Question 20

Pneumococcal, Streptococcal

Answer 20

Pen G

Question 21

Meningococcal, Neisseria, syphilis, anaerobes, Listeria

Answer 21

Pen V

Question 22

Staph. aureus, Staph. epidermis

Answer 22

Nafcillin

Question 23

H. influenzae, S. pneumoniae, E. coli

Answer 23

Amoxicillin

Question 24

P. aeruginosa, Enterobacter, B. fragilus, Klebsiella

Answer 24

Ticarcillin, Piperacillin

Question 25

1st generation vs. 5th generation cephalosporins

Answer 25

increasing activity against G- bacteria and anaerobes increasing resistance to Beta-lactams increasing penetration into CNS

Question 26

1st generation cephalosporin

Answer 26

cefazolin

Question 27

used immediately before surgery to prevent surgical site infections

Answer 27

cefazolin

Question 28

2nd generation cephalosporin

Answer 28

cefoxitin

Question 29

3rd generation cephalosporin

Answer 29

ceftriaxone

Question 30

Tx. of meningitis and gonorrhea + empiric chlamydia

Answer 30

ceftriaxone

Question 31

4th generation cephalosporin

Answer 31

cefepime

Question 32

empirical treatment of hospitalized patients when resistance due to extended spectrum beta-lactamases is suspected

Answer 32

cefepime

Question 33

Uses - multi-drug resistant infections, anaerobic and mixed infections

Answer 33

imipenem/cilastatin

Question 34

reason to combine imipenem with cilastatin

Answer 34

cilastatin is dipeptidase inhibitor that prevents renal inactivation

Question 35

narrow spectrum drug with activity against G- aerobic bacteria

Answer 35

aztreonam

Question 36

considered safe to give to patients with penicillin allergy

Answer 36

aztreonam

Question 37

tricyclic glycopeptide antibiotic

Answer 37

vancomycin

Question 38

MOA: prevent polymerization of cell wall precursors; blocks addition of NAM-NAG to polymer chain

Answer 38

vancomycin

Question 39

active only against G+ bacteria (S. aureus and S. epidermis)

Answer 39

vancomycin

Question 40

tx for VRSA and VRE

Answer 40

linezolid, daptomycin, quinupristin/dalfopristin

Question 41

treatment of CDAD

Answer 41

vancomycin, metronidazole(1st choice)

Question 42

alternative to penicillin in allergic patients w/ severe G+ infections

Answer 42

vancomycin

Question 43

Adverse reactions to vancomycin

Answer 43

ototoxic and nephrotoxic; "red man syndrome", thrombophlebitis

Question 44

bactericidal phosphoenolpyruvate analogue

Answer 44

fosfomycin

Question 45

treatment of uncomplicated G- UTIs

Answer 45

fosfomycin

Question 46

inhibits production of murein monomers

Answer 46

fosfomycin

Question 47

enters bacterium via glycerophosphate transporter

Answer 47

fosfomycin

Question 48

inhibits bactoprenol dephosphorylation (lipid carrier)

Answer 48

bacitracin

Question 49

drugs that make up Neosporin

Answer 49

bacitracin, neomycin, polymyxin B

Question 50

Resistance to Vancomycin

Answer 50

variations in peptide terminus produce 1000-fold decrease in binding affinity