antibiotic action Flashcards

1
Q

oxazolidinones

A

bind 23S rRNA and prevent 70S complex

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2
Q

streptomycin and tobramycin (and gentamycin and amikacin)

A

bind 30S to distort A site, inhibits protein synthesis

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3
Q

tetracyclines

A

bind 16S rRNA of 30S to prevent aa- tRNA to A site

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4
Q

rifampin and rifabutin

A

bind RNA polymerase and prevent transcription

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4
Q

macrolides (erythromycin)

A

-bind 23 rRNA in 50S to block translocation
-formation 50S subunit

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5
Q

chloramphenicol

A

bind 50S and inhibit peptidyltransferase

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6
Q

quinolones (ciprofloxacin)

A

interfere with type II topoisomerases and stabilize DNA double strand breaks

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7
Q

metronidazole

A

produce DNA radicals

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8
Q

sulfonamids and trimethoprim

A

Act to inhibit folic acid synthesis in bacteria

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8
Q

Bacitracin

A

Prevent recycling of lipid carrier

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9
Q

Polymixins

A

Binds phospholipids and disrupts inner/outer membranes of gram negative bacteria = topical and toxic

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10
Q

Isoniazid and Ethionamide

A

Inhibits SYNTHESIS of mycolic acid

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11
Q

Ethambutol

A

Inhibits ATTACHMENT of mycolic acid in the cell wall

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12
Q

Cycloserine

A

Cyclic analog of alanine; crosses blood brain barrier and is an NMDA receptor agonist

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13
Q

What are the polypeptide antibiotics?

A

Bacitracin
Polymixins

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14
Q

What are the beta-lactams?

A

Penicillins
Cephalosporins
Carbapenems
Monobactams

15
Q

Penicillins

A

Mimicks the structure of D-Ala-D-Ala dipeptide; inhibits transpeptidation

16
Q

What is the mechanism of resistance to penicillin?

A

Hydrolysis of B-lactam ring by B-lactamase

17
Q

What is the mechanism of resistance to vancomycin (glycopeptides)?

A

Change in binding site in the peptidoglycan target

18
Q

What is the mechanism of resistance to oxazolidinones (linezolid)?

A

Mutations in 23S rRNA

19
Q

What is the mechanism of resistance to tetracyclines?

A

Efflux pump pushes drug out of cell

20
Q

What is the mechanism of resistance to quinolones (ciprofloxacin)?

A

Mutations in genes encoding DNA gyrase and topoisomerase IV (type II topoisomerases)