Abx II (lecture) Flashcards

1
Q

What is the MoA of linezolid?

A

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

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2
Q

What is the spectrum of Linezolid?

A

Broad G + specific

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3
Q

What is the indication of Linezolid use?

A

Multi drug resistant strains

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4
Q

What is the mechanism of linezolid resistance?

A

Mutation of the 50s subunit preventing linezolid binding

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5
Q

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

A

Enhanced effects may result

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6
Q

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

A

Doxycycline and Minocycline

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7
Q

What is the mechanism of tetracyclines?

A

Bind the 30s subunit

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8
Q

What is the spectrum of tetracyclines?

A

Broad, mostly G +

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9
Q

What Rx is indicated in Lyme disease?

A

Doxy

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10
Q

How does milk influence tetracycline uptake?

A

Cations hinder

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11
Q

What are two absolute contraindications of tetracycline use?

A

Pregnancy and under 8 y.o.

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12
Q

What are the three mechanisms of tetracycline resistance?

A

Efflux pump
Tet-O: Ribosome protecting proteins
Enzymatic inactivation

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13
Q

What is the MoA of tigecycline?

A

Bind the 30s subunit

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14
Q

What is the spectrum of tigecycline?

A

Broad G + and G - anaerobe and aerobes

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15
Q

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

A

Tigecycline

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16
Q

What is the MoA of tigecycline (2) resistance?

A

TetX inactivation

AcrAB efflux

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17
Q

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

A

Aminoglycosides

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18
Q

What is the MoA of aminoglycosides?

A

Bind 30s subunit and initiate premature termination

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19
Q

What is the spectrum of aminoglycosides?

A

Broad G - aerobics

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20
Q

What are the 4 main adverse effects of aminoglycosides?

A

Nephrotoxic
Ototoxic
Curare-like muscular blockade
Nerve dysfunction

21
Q

With which Abx group are aminoglycosides synergistic?

22
Q

What are the 2 mechanisms of amino glycoside resistance?

A

Enzyme inactivation

Decreased permeability to inner membrane

23
Q

What is the MoA of chloramphenicol?

A

Prevent transferase on the 50s subunit

24
Q

What is the spectrum of chloramphenicol?

A

Broad G -, most anaerobes

25
How is chloramphenicol metabolized?
Hepatic inactivation and renal excretion
26
What are the clinical uses of chloramphenicol?
Limited: typhoid, bacterial meningitis, anaerobe infections, rickettsial
27
What is the MoA of chloramphenicol toxicity?
Mitochondrial 70s ribosome inhibition
28
What is the concern with administration of chloramphenicol to neonates?
Gray baby syndrome (40% fatal)
29
What is the mechanism of resistance with chloramphenicol and in what bacteria (2 genera) is this a primary concern?
Decrease membrane permeability Enzyme inactivation Salmonella and Shigella
30
What drug classification do erythromycin, clarithromycin, and azithromycin fall under?
Macrolides
31
What is the spectrum of macrolides?
G + >> G -
32
What is the DoC of sinusitis and mild pneumonia?
Azithromycin
33
How are microlides excreted?
Mainly biliary
34
What macrolide is contraindicated in pregnancy, which is used?
Erythromycin is contraindicated | Azithromycin is used
35
What are the mechanisms (4) of resistance to macrolides?
ATP-dependent efflux MLSB decreased binding esterase hydrolysis Decreased RNA binding
36
What drug is indicated for B. fragilis, Peptococcus, and Clostridium?
Clindamycin
37
What are the routes of clindamycin administration?
All: oral, topical, IM or IV (fro serious infections)
38
What are the 3 sites of clindamycin adverse effects?
``` neuromuscular transmission inhibition GI: - Life threatening pseudomembranous enterocolitis - C. difficile overgrowth - Diarrhea Skin: Rash (esp with HIV and AIDS pts.) ```
39
What is the benefit of clinamycin over macrolides?
No ATP dependent efflux
40
What class of Abx ends in "-pristin"?
Streptogramins
41
What is the DoC for vancomycin-resistant F. faecium and S. aureus and Strep pyogenes skin infections?
Streptogramins
42
How are quinupristin and dalfopristin synergistic?
dalf enhances quin binding, which inhibits translocation
43
What is a special consideration of streptogramin administration?
5% dextrose only over 1 hr
44
How do streptogramins effect liver metabolism?
CYP3A4 inhibitor
45
What are the 3 mechanisms of streptogramin resistance?
ATP-dependent efflux MLSB mutations fo rRNA Lactonase and acetyl transferase
46
What is the first line drug for UTI?
Nitrofurantoin
47
What may nitrofurantoin induce in G6PD?
Hemolytic anemia
48
What is a special consideration of nitrofurantoin used during pregnancy?
Safe during first 6 months
49
Can nitrofurantoin be used during kidney failure?
NO