Cell Wall Inhibitors

Question 1

Aztreonam spectrum:

Answer 1

Gram-negative rods (pseudomonas); monocyclic B-lactam use on penicillin-allergic patients

Question 2

What are the penicillinase-sensitive penicillins?

Answer 2

Penicillin V (oral), Penicillin G (IV), Benzathine (IM injection)

Question 3

spectrum of anti-psuedomonal penicillins

Answer 3

broad activity against gram(-)

pseudomonas

Question 4

anti-pseudomonal penicillins

Answer 4

ticarcillin

piperacillin

Question 5

What is administered with penicillinase-sensitive penicillins and why?

Answer 5

Probenecid to lengthen the half-life of the drugs; prevents renal excretion of weak acids

Question 6

What are the penicillinase-resistant penicillins

Answer 6

Nafcillin, Dicloxicillin

Question 7

What is the spectrum for penicillinase-sensitive penicillins?

Answer 7

Gram +

Question 8

What is the spectrum for penicillinase-resistant penicillins

Answer 8

MSSA, other staph infections

Question 9

What is ampicillin used specifically to treat?

Answer 9

pseudomembranous colitis

Question 10

What is the spectrum for the aminopenicillins?

Answer 10

Wider spectrum, can treat Gram -

Question 11

What is ampicillin used specifically to treat?

Answer 11

pseudomembranous colitis

Question 12

Spectrum for Ist gen. Cephalosporins

Answer 12

Gram + cocci

Question 13

Spectrum for 2nd gen. Cephalosporins

Answer 13

more Gram - activity, weaker Gram + activity

Question 14

Spectrum for 3rd gen. Cephalosporins

Answer 14

Streptococci and more serious Gram -

can cross blood-brain barrier

Question 15

What Cephalosporin generation is strong against C. diff?

Answer 15

3rd generation

Question 16

Spectrum for 4th gen. Cephalosporins

Answer 16

Broad spectrum (Gram +, Gram -, pseudomonas)

Question 17

Spectrum for 5th gen. Cephalosporins

Answer 17

MRSA that is resistant to other beta-lactams

Question 18

What is the general mechanism of action for cephalosporins?

Answer 18

beta-lactams, bactericidal

sensitive to beta-lactamases

Question 19

ticarcillin is often given in combination with _____ to reduce susceptibility to penicillinases

Answer 19

clavulanate

Question 20

piperacillin is often given in combination with ____ to reduce susceptibility to penicillinases

Answer 20

tazobactam

Question 21

why are penicillins combined with probenecid?

Answer 21

penicillins have a short half-life

probenecid impairs renal secretion of weak acids –> increases the life of penicillins

Question 22

why are penicillins combined with beta-lactamase inhibitors?

Answer 22

beta-lactamase inhibitors bind irreversibly to beta-lactamases –> prevent the beta-lactamase cleavage of the beta-lactam ring –> allows the beta-lactam drug to be effective

Question 23

T/F: Aztreonam is sensitive to beta-lactamases

Answer 23

True

Question 24

Carbapenems spectrum

Answer 24

Broad spectrum, but MRSA is resistant; MUST BE GIVEN WITH CILASTATIN

Question 25

Carbapenem delivery:

Answer 25

IV only (no oral); MUST BE GIVEN WITH CILASTATIN

Question 26

Carbapenem side effects

Answer 26

GI stress, renal dysfunction

Question 27

Describe how renal enzyme react with carbapenems

Answer 27

Form a toxic nephrotoxic metabolite; given with cilastatin to prevent this

Question 28

Polymixin B mechanism of action

Answer 28

binds phophatidylethanolamine in membrane, creates holes; binds LPS and pulls out of cell membrane

Question 29

Polymixin B spectrum

Answer 29

Treat multidrug resistant Gram - bacilli (pseudomonas and Klebsiella)

Question 30

Polymixin B side effects

Answer 30

nephrotoxicity

Question 31

Daptomycin mechanism of action

Answer 31

Bind cell membrane, aggregates, depolarizes membrane-->cell death/bactericidal

Question 32

Daptomycin spectrum

Answer 32

only Gram + (particularly Vanco-resistant MRSA)

Question 33

Daptomycin side effects

Answer 33

binds surfactants also, causing pneumonia

Question 34

Daptomycin resistance mechanism

Answer 34

addition of positive lysines to cell surface; repels positive charged drug

Question 35

Vancomycin spectrum

Answer 35

C. diff, MRSA; poorly absorbed

Question 36

Vancomycin mechanism

Answer 36

Binds aa on cell wall precursor to inhibit release from bactroprenol carrier-->inhibits transglycosylase

Question 37

Vancomycin resistance mechanism

Answer 37

enterococci (and some staphylococcus) change the aa sequence to prevent binding

Question 38

What drugs will have increased efflux as the resistance mechanism?

Answer 38

cephalosporins, aztreonam

Question 39

What drugs will have an altered drug target as the resistance mechanism?

Answer 39

beta-lactams, Vancomycin

Question 40

What drugs will have drug inactivation as the resistance mechanism?

Answer 40

penicillins, cephalosporins,