Nucleic acid synthesis- individual facts

Question 1

Name the drugs that interfere with RNA polymerase

Answer 1

Rifampin, Fidaxomicin

Question 2

Mechanism of Rifampin

Answer 2

Binds bacterial RNA pol at active center, blocks mRNA elongation

Question 3

Spectrum of Rifampin

Answer 3

Mycobacterium tuberculosis (Treated with 4 total antibiotics)

Question 4

Resistance to Rifampin

Answer 4

Intrinsic: Unable to bind to Beta subunit of RNA pol
Acquired: mutations in rpoB gene prevent binding

Question 5

Side effects of Rifampin

Answer 5

Turns body fluids red/orange, Increased liver enzymes, GI upset

Question 6

Mechanism of Fidaxomicin

Answer 6

Inhibits RNA pol

Question 7

Spectrum of Fidaxomicin

Answer 7

C. diff, C. diff, C. diff, Gram+ anaerobes, Very narrow

Question 8

Resistance to Fidaxomicin

Answer 8

Point mutation in RNA pol observed in vitro

Question 9

Side effects of Fidaxomicin

Answer 9

very few due to low absorption

Question 10

Name Fluoroquinolones

Answer 10

Ciprofloxacin, levofloxacin, moxifloxacin. FLOXACIN

Question 11

Mechanism of Fluoroquinolones

Ciprofloxacin, levofloxacin, moxifloxacin

Answer 11

Binds topoisomerase which leads to DNA damage

Question 12

Spectrum of Fluoroquinolones

Ciprofloxacin, levofloxacin, moxifloxacin

Answer 12

Broad, Gram+, Gram-, atypical organisms (Mycoplasma), Hospital-acquired pneumonia, UTIs

Question 13

Resistance to Fluoroquinolones

Ciprofloxacin, levofloxacin, moxifloxacin

Answer 13

Active efflux of drug, changes in topoisomerase

Question 14

Adverse effects of fluoroquinolones

Ciprofloxacin, levofloxacin, moxifloxacin

Answer 14

Gi, confusion, photosensitivity, C. diff colitis, Chelates Calcium, Iron, Aluminum and Zinc.

Question 15

What is ciprofloxacin used for

Answer 15

intentionally spread diseases (biowarfare)

Question 16

Mechanism of Sulfonamides

Answer 16

Folate antagonist, competes for active site of folate synthesis enzyme dihyropteroate synthetase

Question 17

Spectrum of sulfonamides

Answer 17

Bacteria and fungi that synthesize their own FH2

Question 18

Resistance to sulfonamides

Answer 18

Bacteria that uptake FH2, increase in PABA, increase in efflux of drug, change in the enzyme

Question 19

Side effects of sulfonamides

Answer 19

Kernicterus, jaundice, complications with warfarin, hemolysis of G-6-p dehydrogenase deficiency

Question 20

Mechanism of trimethoprim

Answer 20

Inhibits final step of FH2 synthesis

Question 21

Resistance to trimethoprim

Answer 21

Altered enzyme, increased enzyme, alternative metabolic pathways

Question 22

Side effects of trimethoprim

Answer 22

GI upset

Question 23

Mechanism of action of Metronidazole and tinadazole

Answer 23

Acts as e- sink generating a free radical and leading to DNA damage

Question 24

Spectrum of metronidazole and tinadazole

Answer 24

Protozoa, C. diff, anaerobic bacteria

Question 25

Resistance to metronidazole and tinadazole

Answer 25

Down regulation of pyruvate:ferredoxin oxidoreductase, leading to decreased activation of drug

Question 26

Side effects of metronidazole and tinadazole

Answer 26

Disulfiram-like reaction with EtOH, Nausea, diarrhea, headache, metallic tase

Question 27

Other notes on metronidazole and tinadazole

Answer 27

Avoid during pregnancy, only anaerobic bacteria

Question 28

Mechanism of Nitrofurantoin

Answer 28

Alters ribosomal proteins that inhibit synthesis of DNA, RNA, cell walls and proteins

Question 29

Spectrum of action of nitrofurantoin

Answer 29

Broad, rapidly excreted in urine in active form

Question 30

Resistance of nitrofurantoin

Answer 30

very rare since it affects so much

Question 31

Side effects of nitrofurantoin

Answer 31

Vomiting and rash

Question 32

Notes on nitrofurantoin

Answer 32

Only used for treating UTIs