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Pharmocolgy > P12:- Intro to Antimicrobial Agents > Flashcards

P12:- Intro to Antimicrobial Agents Flashcards

1
Q

List the features of the Ideal Antimicrobial Agent (8)

A
  • Selective toxicity against microbial target
  • Minimal toxicity to the host
  • Cidal activity (KILLS MICRO-ORGANISMS)
  • Long plasma half-life
  • Good tissue distribution
  • Low binding to plasma proteins
  • Oral and parenteral preparations
  • No adverse interactions with other drugs
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2
Q

How do some antibacterial agents inhibit cell wall synthesis?

A

Target peptidoglycan in bacterial cell wall

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3
Q

Name the two types of agents that inhibit cell wall synthesis

A
  • Beta-lactams (penicillins)

- Glycopeptides

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4
Q

Action of beta-lactams (4)

A
  • Bind to ‘penicillin binding proteins’ (enzymes)
  • these catalyse the synthesis of peptidoglycan
  • Inhibition of cross-linking of cell wall
  • Accumulation of precursor cell wall units
  • Cell lysis
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5
Q

What are beta-lactamases?

A

Enzymes that provide resistance from beta lactams

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6
Q

Name an orally absorbed penicillin

A

Phenoxymethylpenicillin

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7
Q

Name a Penicillin resistant to staphylococcal β-lactamase

A

Flucloxacillin

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8
Q

Action of Glycopeptides (2)

A
  • Bind to terminal acyl-D-alanyl-D-alanine residues

- Prevent incorporation of sub-unit into growing peptidoglycan

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9
Q

What are glycopeptides widely used to treat?

A

MRSA

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10
Q

Name the types of drugs that inhibit protein synthesis (5) and give examples

A
  • Aminoglycosides
  • Tetracyclines
  • Macrolides
  • Lincosamides
  • Mupirocin and Fusidic Acid
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11
Q

Name some Aminoglycosides (2)

A
  • Streptomycin

- Gentamicin

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12
Q

Name some Tetracyclines (2)

A
  • Oxytetracycline

- Doxycycline (used for treatment of periodontitis)

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13
Q

Name some Macrolides (2)

A
  • Erythromycin

- Azithromycin

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14
Q

Name a Lincosamide

A

Clindamycin

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15
Q

Name antibiotics that inhibit precursor synthesis

A

Trimethoprim

Co-trimoxazole

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16
Q

Name antibiotics that inhibit DNA replication

A

Quinolones e.g.
Nalidixic acid
Ciprofloxacin

17
Q

Name antibiotics that inhibit RNA polymerase

A

Rifamycins e.g.

Rifampicin

18
Q

Name antibiotics that break DNA strands

A

5-nitroimidazoles e.g.

metronidazole (good against anaerobic bacteria)

19
Q

Action of Polyenes (anti fungal agents)

A
  • Bind to sterols in fungal cell membranes
  • Interfere with membrane integrity
  • Allows leakage of essential metabolites
20
Q

Examples of Polyenes (2)

A
  • Nystatin

- Amphotericin B

21
Q

Action of Azoles (anti fungal agents)

A
  • Disrupts biosynthesis of ergosterol

- Disrupts fungal membrane functions.

22
Q

What is Aciclovir (anti viral agents) used for?

A

Management of oro-facial herpes simplex infections

23
Q

What are the 3 mechanisms of resistance to antimicrobial agents?

A
  • Altered target (target enzyme lowers affinity to drug)
  • Altered uptake (alternative entry allow organism to pump drug out)
  • Drug inactivation (production of enzyme which inactivates drug)
24
Q

What is Pharmacodynamics?

A

Relationship between drug concentration and antimicrobial effect.

25
Q

What types of drug are included in beta-lactams

A

Penicillins and cephalosporins

26
Q

What do all beta lactams have in common

A

All contain a beta lactam ring in their chemical structure

27
Q

What can protect beta lactams from beta-lactamases

A

enzyme inhibitors like clavulanic acid

28
Q

How are vancomycin and teicoplanin administrated and what type of bacteria are they active against

A

Only administered by injection and are only active against gram +ve organisms
(these are glycopeptides btw)

29
Q

What are the mechanisms of antibiotics that inhibit nucleic acid synthesis

A
  • Inhibitor of precursor synthesis
  • Inhibitors of DNA replication
  • Inhibitors of RNA polymerase
  • DNA strand breakage
30
Q

What are the general mechanisms of antibacterial agents

A
  • Inhibitors of cell wall synthesis
  • Inhibitors of protein synthesis
  • Inhibitors of nucleic acid synthesis
31
Q

How are polyenes used

A

Topical preparations like mouthwash and lozenges to treat oral candidosis

32
Q

Name some Azoles (anti fungal agents) and what they’re used to treat

A

Fluconazole
Itraconazole
Miconazole
(used to treat topical candida infections)

33
Q

How does aciclovir’s mechanism allow it to attack viruses

A

The viral thymidine kinase enzyme phosphorylates acyclovir and traps it within infected cells

34
Q

What are the 2 patterns of antimicrobial killing activity and give examples for both

A
  • concentration-dependent killing e.g. amphotericin and metronidazole
  • time dependent killing e.g. beta-lactams

Pharmocolgy (22 decks)

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