Abx II (lecture)

Question 1

What is the MoA of linezolid?

Answer 1

Bind to 50s of bacterial tRNA, preventing 70s formation

Question 2

What is the spectrum of Linezolid?

Answer 2

Broad G + specific

Question 3

What is the indication of Linezolid use?

Answer 3

Multi drug resistant strains

Question 4

What is the mechanism of linezolid resistance?

Answer 4

Mutation of the 50s subunit preventing linezolid binding

Question 5

What consideration is related to linezolid use with andrenergics, serotonergics and high tyramine intake (wine, cheese, and picked meats)?

Answer 5

Enhanced effects may result

Question 6

What are two drugs are considered tetracyclines (other than tetracycline of course)?

Answer 6

Doxycycline and Minocycline

Question 7

What is the mechanism of tetracyclines?

Answer 7

Bind the 30s subunit

Question 8

What is the spectrum of tetracyclines?

Answer 8

Broad, mostly G +

Question 9

What Rx is indicated in Lyme disease?

Answer 9

Doxy

Question 10

How does milk influence tetracycline uptake?

Answer 10

Cations hinder

Question 11

What are two absolute contraindications of tetracycline use?

Answer 11

Pregnancy and under 8 y.o.

Question 12

What are the three mechanisms of tetracycline resistance?

Answer 12

Efflux pump
Tet-O: Ribosome protecting proteins
Enzymatic inactivation

Question 13

What is the MoA of tigecycline?

Answer 13

Bind the 30s subunit

Question 14

What is the spectrum of tigecycline?

Answer 14

Broad G + and G - anaerobe and aerobes

Question 15

What “-cycline” is safe for use in renal failure and mild hepatic failure?

Answer 15

Tigecycline

Question 16

What is the MoA of tigecycline (2) resistance?

Answer 16

TetX inactivation

AcrAB efflux

Question 17

Streptomycin, gentamicin, neomycin, kanamycin and spectinomycin are all examples of what class of Abx?

Answer 17

Aminoglycosides

Question 18

What is the MoA of aminoglycosides?

Answer 18

Bind 30s subunit and initiate premature termination

Question 19

What is the spectrum of aminoglycosides?

Answer 19

Broad G - aerobics

Question 20

What are the 4 main adverse effects of aminoglycosides?

Answer 20

Nephrotoxic
Ototoxic
Curare-like muscular blockade
Nerve dysfunction

Question 21

With which Abx group are aminoglycosides synergistic?

Answer 21

B-lactams

Question 22

What are the 2 mechanisms of amino glycoside resistance?

Answer 22

Enzyme inactivation

Decreased permeability to inner membrane

Question 23

What is the MoA of chloramphenicol?

Answer 23

Prevent transferase on the 50s subunit

Question 24

What is the spectrum of chloramphenicol?

Answer 24

Broad G -, most anaerobes

Question 25

How is chloramphenicol metabolized?

Answer 25

Hepatic inactivation and renal excretion

Question 26

What are the clinical uses of chloramphenicol?

Answer 26

Limited: typhoid, bacterial meningitis, anaerobe infections, rickettsial

Question 27

What is the MoA of chloramphenicol toxicity?

Answer 27

Mitochondrial 70s ribosome inhibition

Question 28

What is the concern with administration of chloramphenicol to neonates?

Answer 28

Gray baby syndrome (40% fatal)

Question 29

What is the mechanism of resistance with chloramphenicol and in what bacteria (2 genera) is this a primary concern?

Answer 29

Decrease membrane permeability
Enzyme inactivation
Salmonella and Shigella

Question 30

What drug classification do erythromycin, clarithromycin, and azithromycin fall under?

Answer 30

Macrolides

Question 31

What is the spectrum of macrolides?

Answer 31

G +&raquo_space; G -

Question 32

What is the DoC of sinusitis and mild pneumonia?

Answer 32

Azithromycin

Question 33

How are microlides excreted?

Answer 33

Mainly biliary

Question 34

What macrolide is contraindicated in pregnancy, which is used?

Answer 34

Erythromycin is contraindicated

Azithromycin is used

Question 35

What are the mechanisms (4) of resistance to macrolides?

Answer 35

ATP-dependent efflux
MLSB decreased binding
esterase hydrolysis
Decreased RNA binding

Question 36

What drug is indicated for B. fragilis, Peptococcus, and Clostridium?

Answer 36

Clindamycin

Question 37

What are the routes of clindamycin administration?

Answer 37

All: oral, topical, IM or IV (fro serious infections)

Question 38

What are the 3 sites of clindamycin adverse effects?

Answer 38

neuromuscular transmission inhibition
GI: 
   - Life threatening pseudomembranous enterocolitis
   - C. difficile overgrowth
   - Diarrhea
Skin: Rash (esp with HIV and AIDS pts.)

Question 39

What is the benefit of clinamycin over macrolides?

Answer 39

No ATP dependent efflux

Question 40

What class of Abx ends in “-pristin”?

Answer 40

Streptogramins

Question 41

What is the DoC for vancomycin-resistant F. faecium and S. aureus and Strep pyogenes skin infections?

Answer 41

Streptogramins

Question 42

How are quinupristin and dalfopristin synergistic?

Answer 42

dalf enhances quin binding, which inhibits translocation

Question 43

What is a special consideration of streptogramin administration?

Answer 43

5% dextrose only over 1 hr

Question 44

How do streptogramins effect liver metabolism?

Answer 44

CYP3A4 inhibitor

Question 45

What are the 3 mechanisms of streptogramin resistance?

Answer 45

ATP-dependent efflux
MLSB mutations fo rRNA
Lactonase and acetyl transferase

Question 46

What is the first line drug for UTI?

Answer 46

Nitrofurantoin

Question 47

What may nitrofurantoin induce in G6PD?

Answer 47

Hemolytic anemia

Question 48

What is a special consideration of nitrofurantoin used during pregnancy?

Answer 48

Safe during first 6 months

Question 49

Can nitrofurantoin be used during kidney failure?

Answer 49

NO