Antibiotics IV: Inhibitors of Nucleic Acid Synthesis and Plasma Membrane Disruptors

Question 1

MOA: bactericidal agent that inhibits one of two topoisomerase II enzymes (DNA gyrase or topoisomerase IV)

Answer 1

ciprofloxacin

Question 2

fluoroquinolones

Answer 2

ciprofloxacin

Question 3

widely used to treat common urogenital, respiratory and GI infections; prophylaxis for anthrax

Answer 3

ciprofloxacin

Question 4

Adverse effects: tendon rupture; prolongation of Q-T interval; confusion, somnolence, visual disturbances in elderly

Answer 4

ciprofloxacin

Question 5

causes CDAD

Answer 5

ciprofloxacin (and clindamycin)

Question 6

Interactions: theophylline, warfarin; multivalent cations

Answer 6

ciprofloxacin

Question 7

prodrug - reduced in anaerobes by pyruvate-ferredoxin oxidoreductase or nitroreductase

Answer 7

metronidazole

Question 8

MOA: bactericidal in anaerobic bacteria, sensitive protozoa; cause DNA strands to break and lose helical structure

Answer 8

metronidazole

Question 9

Drug of choice for CDAD

Answer 9

metronidazole (vancomycin is 2nd)

Question 10

Used in combo w/ tetracycline and bismuth subsalicylate to eradicate H. pylori

Answer 10

metronidazole

Question 11

antiparasitic agent

Answer 11

metronidazole

Question 12

Adverse reactions: dark red-brown urine; N/V when combined w/ ethanol

Answer 12

metronidazole

Question 13

MOA: bacteriostatic; analog of PABA; ultimately prevents DNA replication

Answer 13

sulfamethoxazole

Question 14

resistance due to synthesis of sufficient PABA, mutation in active site results in reduced drug affinity, and/or decreased drug uptake

Answer 14

sulfamethoxazole

Question 15

Therapeutic uses: G+/G- infections; UTIs

Answer 15

sulfamethoxazole (in combo with trimethoprim)

Question 16

Adverse reactions: kernicterus in newborns, Stevens-Johnson syndrome, hemolytic anemia

Answer 16

sulfamethoxazole

Question 17

MOA: competitive inhibitor of dihydrofolate reductase

Answer 17

trimethoprim

Question 18

Resistance due synthesis of increase amount of DHFR, production of mutated DHFR w/ lower drug affinity, and reduced drug uptake

Answer 18

trimethoprim

Question 19

Uses: alone for initial therapy of uncomplicated UTIs

Answer 19

trimethoprim

Question 20

Adverse reactions: bone marrow suppression in folate-deficient patients; fetal malformations in high doses

Answer 20

trimethoprim

Question 21

fixed-dose combination of TMP/SMX

Answer 21

co-trimoxazole

Question 22

Therapeutic uses: UTIs, Pneumocystis jirovicii pneumonia, otitis media

Answer 22

co-trimoxazole

Question 23

MOA: bactericidal combo that results from inhibition of sequential steps of folate biosynthesis

Answer 23

co-trimoxazole

Question 24

MOA: inhibition of bacterial RNA polymerase; bactericidal against G+

Answer 24

fidaxomicin

Question 25

Therapeutic uses: C. difficile colitis (minimally disruptive to normal flora)

Answer 25

fidaxomicin

Question 26

cyclic lipopeptides

Answer 26

daptomycin

Question 27

MOA: Ca-dependent insertion of lipophilic tail into plasma membrane that permits efflux of intracellular K+

Answer 27

daptomycin

Question 28

inhibits DNA, RNA, and protein synthesis

Answer 28

daptomycin

Question 29

causes membrane depolarization - loss of membrane potential

Answer 29

daptomycin

Question 30

inactivated by surfactant; not effective against pneumonia

Answer 30

daptomycin

Question 31

Therapeutic Uses: MRSA, VRSA; bacteremia and right-sided endocarditis (MRSA)

Answer 31

daptomycin

Question 32

Adverse reaction - myopathy (monitor CPK)

Answer 32

daptomycin

Question 33

polymyxins

Answer 33

colistin

polymyxin B

Question 34

MOA: binds to neg-charged LPS in outer membrane of G- bacteria

Answer 34

polymixins

Question 35

hydrophobic tail disrupts both outer and plasma membranes; increases membrane permeability

Answer 35

polymixins

Question 36

polymyxin formulation for topical and oral use

Answer 36

colistin sulfate

Question 37

polymyxin formulation for parenteral use

Answer 37

colistimethate (prodrug of colistin)

Question 38

treatment of last resort for serious MDR G- bacterial infections (ESCAPE pathogens)

Answer 38

colistimethate

Question 39

topical for infections of skin, mucous membranes, eye and ear

Answer 39

colistin sulfate, polymyxin B