Fluoroquinolones

Question 1

What is FQ’s MoA? - Bacteriocidal or bacteriostatic?

Answer 1

Inhibition of DNA gyrase and topoisomerase IV - Bacteriocidal

Question 2

What is FQ’s primary mechanism of resistance? - What are some additional MoR’s it has?

Answer 2

Chromosomal mutations in DNA gyrase or topoisomerase IV - Also development of efflux pumps, plasmid-mediated resistance, altered cell wall permeability (porins)

Question 3

Which of the FQ’s are active against gram-positive aerobes? (Which aren’t, then?)

Answer 3

Levofloxacin, moxifloxacin, gemifloxacin (Not ciprofloxacin!)

Question 4

Describe the relative activity of FQs against gram-negative aerobes. What about for pseudomonas?

Answer 4

cipro = levo > moxi cipro > levo, NOT moxi or gemi

Question 5

Which of the FQ’s are active against anaerobes?

Answer 5

Only moxifloxacin

Question 6

Which of the FQ’s are active against atypical bacteria?

Answer 6

All FQs

Question 7

Which FQ(s) are useful against CA-PNA (CAP)?

Answer 7

Levo, moxi, gemi

Question 8

Which FQ(s) are useful against HA-PNA?

Answer 8

Cipro (+ something for gram-positive coverage), levo

Question 9

Which FQ(s) are useful against sinusitis/bronchitis?

Answer 9

All

Question 10

Which FQ(s) are useful against UTI/prostatitis?

Answer 10

Cipro, levo

Question 11

Besides previously mentioned, what else are FQs useful for? (not sure how to ask this question)

Answer 11

Bone infections, STD’s, TB, intra-abdominal w/ added anaerobe coverage

Question 12

What are the most common adverse affects of FQs? (2) What else can occur?

Answer 12

GI, CNS - Prolonged QTc interval - Tendonitis, tendon rupture - Hepatotoxicity, photosensitivity, hypersensitivity, rash, articular damage

Question 13

What demo should not use FQs? (contraindicated)

Answer 13

Pregnant women and children

Question 14

What drugs do FQs interact w/?

Answer 14

• Divalent, trivalent cations: separate administration to avoid chelation and decreased absorption - Warfarin, cyclosporine, theophylline

Question 15

Methicillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae (including PRSP), Viridans streptococci, and Enterococcus spp. are eg’s of what class of bacteria?

Answer 15

Gram-positive aerobes

Question 16

Enterobacteriaceae including Citrobacter spp. E. coli, Klebsiella spp, Enterobacter spp, Proteus spp, Salmonella, Shigella, Serratia marcescens, etc; H. influenzae, M. catarrhalis, Neisseria spp., and Pseudomonas aeruginosa are eg’s of what class of bacteria?

Answer 16

Gram-negative aerobes

Question 17

Bacteroides spp such as b. fragilis are eg’s of what class of bacteria?

Answer 17

Anaerobes

Question 18

Legionella pneumophila, Chlamydophila and Chlamydia spp., Mycoplasma spp. and Ureaplasma urealyticum are eg’s of what class of bacteria?

Answer 18

Atypical bacteria

Question 19

All of the FQs are eliminated mostly through the __________ with the exception of __________, which is eliminated through the __________.

Answer 19

• kidney - moxi - liver (therefore can’t treat UTI)

Question 20

Metronidazole is mainly used against what class of microbe?

Answer 20

Anaerobes

Question 21

What is the MoA of metronidazole? - What molecule is responsible for this and how? - Bacteriocidal or bacteriostatic?

Answer 21

Inhibits DNA synthesis - Ferredoxins (which nlly make ATP). Metronidazole binds them and creates an e- sink. Drives more drug into cell and reactive species are made. - Bacteriocidal

Question 22

How common is the development of resistance w/metronidazole? What are 2 ways in which bugs acquire resistance to metronidazole?

Answer 22

*Uncommon - Altered growth requirements (e.g. higher local O2 conc.) - Altered ferredoxin levels (lower levels)

Question 23

What 2 types of anaerobic bacteria is metronidazole most active against?

Answer 23

• Bacteroides spp. (all) - Clostridium spp. (all)

Question 24

Metronidazole: - IV/PO or both? - Does it penetrate the CSF? - How is it eliminated?

Answer 24

• Both - Yes - Liver

Question 25

What are the clinical uses of metronidazole? Metronidazole is the drug of choice for _____________.

Answer 25

• Anaerobic Infections (including in the CNS): Intraabdominal, pelvic, (skin/soft tissue), diabetic foot and decubitus ulcer infections; brain abscess, trichomonas MILD to MODERATE c-dif dz

Question 26

What are the most common side effects from metronidazole? What are the most serious side effects?

Answer 26

• GI (stomatitis–metallic taste) - CNS (peripheral neuropathy) - Teratogenic (avoid during pregnancy)

Question 27

What 2 important drugs does metronidazole interact with?

Answer 27

• Warfarin (increased anticoagulant effect) - Alcohol (disulfiram rxn; don’t give to alcoholics)

Question 28

FQs are the DOC for what atypical bacterium?

Answer 28

* Legionella

Question 29

What is the target organism for cipro and levo when targeting gram-negative aerobes?

Answer 29

Pseudomonas aeruginosa (NOT moxi)

Question 30

What are the target organisms for levo, moxi, and gemi when targeting gram-positive aerobes?

Answer 30

• Methicillin-susceptible Staphylococcus aureus* - Streptococcus pneumoniae (including PRSP)*

Question 31

Which FQ has good CSF penetration?

Answer 31

Moxifloxacin

Question 32

Trichomonas vaginalis Entamoeba histolytica Giardia lamblia Gardnerella vaginalis are all examples of what class that metronidazole inhibits?

Answer 32

Anaerobic protozoa

Question 33

Bacteroides spp. (ALL)* Fusobacterium Prevotella spp. Clostridium spp. (ALL)* Helicobacter pylori Are all examples of what class of organism that metronidazole inhibits?

Answer 33

Anaerobic bacteria