(Lecture) Actions of Antimicrobials Flashcards

1
Q

Chemical substances that are produced by microorganisms that has the capacity to inhibit or kill other microorganisms.

A

Antibiotics

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2
Q

The lowest concentration of a drug that can inhibit bacterial growth.

A

Minimum-Inhibitory Concentration (MIC)

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3
Q

The lowest concentration of a drug that can still kill bacteria.

A

Minimum-Bactericidal Concentration (MBC)

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4
Q

Ratio of a toxic dose to the therapeutic dose; the higher the index, the more effective the chemotherapeutic agent.

A

Therapeutic Index

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5
Q

Characteristics of Antimicrobial Agents

A

● The agent must be in active form.
● The agent must be able to achieve concentration at the site of infection that is higher than the pathogen’s MIC to be effective.
● Must have selective toxicity.

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6
Q

_____ inhibit cell wall synthesis by binding to the end of the peptidoglycan, preventing transpeptidation.

A

Glycopeptides

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7
Q

Glycopeptides inhibit cell wall synthesis by binding to the end of the peptidoglycan, preventing _____

A

Transpeptidation

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8
Q

Glycopeptides inhibit cell wall synthesis by binding to the end of the _____, preventing transpeptidation

A

Peptidoglycan

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9
Q

What type of Antimicrobial Agents is this based on the description?

● Selective antibiotics with high therapeutic index
● Interferes with the biosynthesis of peptidoglycan
● The beta-lactam antibiotics form covalent complexes with enzymes that generate mature peptidoglycan molecule (transpeptidase enzymes that mediate peptidoglycan cross-linking)
● The active component of the beta-lactam family of drugs is the beta-lactam structure.
● Glycopeptides inhibit cell wall synthesis by binding to the end of the peptidoglycan, preventing transpeptidation.

A

Cell Wall Inhibitors

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10
Q

_____ prevents the formation of dihydropteroate through competitive inhibition of para-aminobenzoic acid with the enzyme dihydropteroate synthase

A

Sulfamethoxazole/SMZ

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11
Q

Sulfamethoxazole/SMZ (a sulfonamide) prevents the formation of dihydropteroate through competitive inhibition of para-aminobenzoic acid with the enzyme _____

A

Dihydropteroate synthase

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12
Q

Sulfamethoxazole/SMZ (a sulfonamide) prevents the formation of _____ through competitive inhibition of para-aminobenzoic acid with the enzyme dihydropteroate synthase

A

Dihydropteroate

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13
Q

_____ blocks the formation of the tetrahydrofolate by inhibiting dihydrofolate reductase.

A

Trimethoprim

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14
Q

Trimethoprim blocks the formation of the _____ by inhibiting dihydrofolate reductase.

A

Tetrahydrofolate

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15
Q

Trimethoprim blocks the formation of the tetrahydrofolate by inhibiting _____

A

Dihydrofolate reductase

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16
Q

What type of Antimicrobial Agents is this based on the description?

● The folic acid pathway provides essential precursor molecules needed for DNA biosynthesis
● Sulfamethoxazole/SMZ (a sulfonamide) prevents the formation of dihydropteroate through competitive inhibition of para-aminobenzoic acid with the enzyme dihydropteroate synthase
● Trimethoprim blocks the formation of the tetrahydrofolate by inhibiting dihydrofolate reductase.

A

Inhibitors of Folate Synthesis

17
Q

These are necessary for DNA replication

A

Topoisomerases I, II, III, and IV

18
Q

_____ affect DNA replication by targeting topoisomerases II (DNA gyrase) in Gram-negative bacteria and Topoisomerase IV in Gram-positive bacteria

A

Quinolones

19
Q

Quinolones affect DNA replication by targeting _____ in Gram-negative bacteria and _____ in Gram-positive bacteria

A

Topoisomerases II
Topoisomerases IV

20
Q

What type of Antimicrobial Agents is this based on the description?

● Topoisomerases I, II, III, and IV are necessary for DNA replication
● Quinolones affect DNA replication by targeting topoisomerases II (DNA gyrase) in Gram-negative bacteria and Topoisomerase IV in Gram-positive bacteria

A

Agents that Interfere with DNA Replication

21
Q

_____ of DNA into RNA is mediated by RNA polymerase

A

Transcription

22
Q

Transcription of DNA into RNA is mediated by _____

A

RNA polymerase

23
Q

_____ targets the RNA polymerase subunit, blocking RNA chain elongation.

24
Q

What type of Antimicrobial Agents is this based on the description?

● Transcription of DNA into RNA is mediated by RNA polymerase
● Rifampin targets the RNA polymerase subunit, blocking RNA chain elongation.

A

Agents that Interfere with DNA Transcription

25
List down some of the antibiotics that target the 30S ribosomal subunit.
Aminoglycosides Spectinomycin Tetracyclines Glycylcyclines
26
List down some of the antibiotics that target the 50S ribosomal subunit.
Macrolides Lincosamides Chloramphenicol Oxazolidinones Streptogramins
27
Only _____ are bactericidal; the rest are bacteriostatic
Aminoglycosides
28
Antibiotics that have side effects
Aminoglycosides, Chloramphenicol, and Tetracycline
29
What type of Antimicrobial Agents is this based on the description? ● Some antibiotics target the 30S ribosomal subunit (aminoglycosides, spectinomycin, tetracyclines, glycylcyclines) ● Others target the 50S ribosomal subunit (macrolides, lincosamides, chloramphenicol, oxazolidinones, streptogramins) ● Only aminoglycosides are bactericidal; the rest are bacteriostatic ● Aminoglycosides, chloramphenicol, and tetracycline have side effects.
Agents that Inhibit Protein Synthesis
30
_____ serve as outer membrane channels that permit the influx of nutrients and efflux of waste products.
Porins
31
_____ are found in bacteria and function as transporter proteins for the extrusion of toxic substances and antibiotics from the interior of the cell to the external environment.
Efflux Pumps
32
_____ are enzymes that hydrolyzes beta-lactams, preventing the antibiotic’s ability to bind transpeptidase enzymes
Beta-lactamases
33
Beta-lactamases are enzymes that hydrolyzes beta-lactams, preventing the antibiotic’s ability to bind _____
Transpeptidase enzymes
34
The inhibitors that bind beta-lactamases and reduces their detrimental effects on the beta-lactam antibiotics.
Clavulanic acid Sulbactam Tazobactam
35
_____ compete with dihydropteroate synthase enzymes to block the formation of nucleotide precursors.
Sulfonamides