U2.1.1 ANTIMICROBIALS Flashcards

1
Q

Substances that inhibit, kill or
destroy microorganisms

A

Antimicrobial Agents

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2
Q

Examples of antimicrobial agents

A

Antibiotics, Antibacterial Agent, Antiviral, Anti-fungal, Anti-parasitic

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3
Q

Sources of Antimicrobial Agents

A
  1. Microorganisms Bacteria or Fungi
  2. Chemically Synthesized
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4
Q

Determine the Spectrum of Action

wide spectrum of action

A

Broad Spectrum

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4
Q

Determine the Spectrum of Action

limited spectrum of action

A

Narrow Spectrum

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5
Q

Determine the Spectrum of Action

Penicillin G, Bacitracin, Clindamycin, Erythromycin, Polymyxin B, Vancomycin

A

Narrow Spectrum

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6
Q

Determine the Spectrum of Action

Action against Gr (+) and Gr (-) bacteria

A

Broad Spectrum

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7
Q

Determine the Spectrum of Action

Tetracycline, Ampicillin, Cephalosporins

A

Broad Spectrum

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8
Q

According to Action

Kill or destroy the microorganism

A

Bacteriocidal Agents

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9
Q

Determine the Spectrum of Action

Disadvantage: Destruction/Inhibition of the normal flora leading to superinfections

A

Broad Spectrum

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10
Q

According to Action

Used ni life threatening infections and in infections in
immunosuppressed patients

A

Bacteriocidal Agents

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11
Q

According to Action

Inhibits the growth of microorganisms

A

Bacteriostatic Agents

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12
Q

According to Action

Chloramphenicol
- Erythromycin, Clindamycon, Sulfonamides, Trimethoprim, Tetracyclines, Tigecycline, Linezolid, Quinupristin

A

Bacteriostatic

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13
Q

According to Action

Aminoglycosides
- B-lactams, Vancomycin, Daptomycin, Teicoplanin, Telavancin, Quinolones, Rifampin, Metronidazole

A

Bactericidal

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14
Q

Actions of Antimicrobial Drugs (Cell wall/ Cell membrane/ 50S Inhibitors/ 30S Inhibitors/ Nucleic Acid Synthesis)

B-lactams, Penicillins, Cephalosporins, Vancomycin

A

For cell wall

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15
Q

Actions of Antimicrobial Drugs (Cell wall/ Cell membrane/ 50S Inhibitors/ 30S Inhibitors/ Nucleic Acid Synthesis)

Polymyxins

A

Cell membrane

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16
Q

Actions of Antimicrobial Drugs (Cell wall/ Cell membrane/ 50S Inhibitors/ 30S Inhibitors/ Nucleic Acid Synthesis)

Erythromycin, Clindamycin, Chloramphenicol, Oxazolidinone-linezolid, Streptogramine-DQ

A

50S Inhibitors

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17
Q

Actions of Antimicrobial Drugs (Cell wall/ Cell membrane/ 50S Inhibitors/ 30S Inhibitors/ Nucleic Acid Synthesis)

Aminoglycosides, Tetracyclines, Glycylcycline-tigecydine

A

30S Inhibitors

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18
Q

Actions of Antimicrobial Drugs (Cell wall/ Cell membrane/ 50S Inhibitors/ 30S Inhibitors/ Nucleic Acid Synthesis)

Nalidixic Acid, Fluoroquinolones, Rifampin

A

DNA synthesis : Nalidixic Acid, Fluoroquinolones
RNA polymerase : Rifampin

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19
Q

Inhibition of Cell Wall Synthesis

Inhibits cell wall synthesis by binding enzymes involved in peptidoglycan production

A

B-lactams

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20
Q

Inhibition of Cell Wall Synthesis

Both gram-pos and gram-neg bacteria but spectrum may vary with the individual antibiotic

A

B-lactams

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21
Q

Inhibition of Cell Wall Synthesis

proteins involved in peptidoglycan production

A

PBPs - Penicillin-binding proteins

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22
Q

Inhibition of Cell Wall Synthesis

MOA: Inhibition of Enzymes needed for peptidoglycan formation

A

Beta Lactam Drugs

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23
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

from Penicillium notatum

A

Penicilin

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24
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

Ampicillin, amoxicillin

A

Aminopenicillins

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25
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

Methicillin, Oxacillin, Nafcillin

A

Penicillinase Resistant Penicillins

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26
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

Aminopenicillins (ampicillin, amoxicillin), Carboxypenicillin (carbenicillin, ticarcillin), Acycalmminopenicillins, Ureidopenicillins

A

Extended Spectrum Penicillin

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27
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

augmentin, Pip-Taz, ampicillin/sulbactam

A

Penicillin Co-drugs

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28
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

source Acremonium

A

Cephalosporins

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29
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

Structurally Similar to penicillin but better able to withstand B-lactamase and more modifiable

A

Cephalosporins

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30
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

original cephalosporin, modified to aminocephalosporanic acid

A

Cephalosporin C

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31
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

Spectrum of Cephalosporins

A

1st Gen - Narrow Spectrum
2nd Gen - Expanded Spectrum
3rd Gen - Broad Spectrum
4th Gen - Extended Spectrum

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32
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

Narrow Spectrum, Aztreonam

A

Monobactams

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33
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

Imipinem, meropenem, doripenem, ertapenem

A

Carbapanems

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34
Q

Inhibition of Cell Wall Synthesis - Beta Lactam Drugs

  • Broad Spectrum (similar to 3rd generation cephalosporins, slightly greater activity against enterics, Pseudomonas, and anaerobes
  • Not effective for MRSA and VRE
A

Carbapanems

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35
Q

Inhibition of Cell Wall Synthesis

MOA: Binds to terminal D-Ala-D-Ala of the pentapeptidyl-glycosyl peptidoglycan intermediates

A

Glycopeptides

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36
Q

Inhibition of Cell Wall Synthesis

Vancomycin, dalbavancin, teicoplamin

A

GLYCOPEPTIDES

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37
Q

Inhibition of Cell Wall Synthesis

Activity is limited to Gram Positive Organisms Only

A

Glycopeptides

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38
Q

Inhibition of Cell Wall Synthesis

  • MOA: inhibit the synthesis of the peptidoglycan precursors in the cytoplasm
  • 2nd line drug for TB
A

Cycloserine

38
Q

Inhibitors of Cell Membrane Function (Disruption of Cell Membrane)

  • Polymyxin B and Polymyxin E (Colistin)
  • Cyclic Polypeptides
A

Polymyxins

39
Q

Inhibitors of Cell Membrane Function (Disruption of Cell Membrane)

Source: Bacillus licheniformis

A

Bacitracin

39
Q

Inhibitors of Cell Membrane Function (Disruption of Cell Membrane)

  • MOA: Inhibits the transport of lipid-bound precursors across the cytoplasmic membrane
  • Toxic; limited to topical application
A

Bacitracin

40
Q

Inhibitors of Cell Membrane Function (Disruption of Cell Membrane)

  • MOA : Act like detergents which interact with phospholipids, increasing permeability
  • Agent of last resort to P. aeruginosa and Acinetobacter infections
  • Toxic (neurotoxic and nephrotoxic)
A

Polymyxins

41
Q

Inhibitors of Cell Membrane Function (Disruption of Cell Membrane)

  • Disrupt membranes of Gr (+) bacteria
  • For VRSA,VRE, MRSA
  • Daptomycins
A

Lipopeptides

41
Q

Inhibition of Folate Synthesis

Enzymes mediating folate synthesis

A

Dihydropteroate synthase & Dihydrofolate reductase

42
Q

Inhibition of Folate Synthesis

is an important precursor in DNA synthesis of bacteria

A

Folate

43
Q

Inhibition of Folate Synthesis

MOA: competitive inhibition of folic acid synthesis. Binding to dihydropteroate synthase (analogue PABA)

A

Sulfonamides

44
Q

Inhibition of Folate Synthesis

  • Moderately Toxic: vomiting, nausea, hypersensitivity reactions
  • Can be antagonistic to certain medications (warfarin, phenytoin, oral hypoglycemic agents)
A

Sulfonamides

45
Q

Inhibition of Folate Synthesis

MOA: blocks the step leading to formation tetrahydrofolate by preventing dihydrofolate reductase mediated recycling of folate coenzymes

A

Trimetroprim

46
Q

Inhibition of DNA Synthesis

MOA: bind and interfere with DNA gyrase and Topoisomerase IV

A

Fluoroquinolones

47
Q

Inhibition of DNA Synthesis

  • Toxicity: Tendinitis; rupture of Achilles tendon
  • Ex. Nalidixic Acid
  • For Enterics, pseudomonads, Staphylococus, Streptococcus, Neisseria
A

Fluoroquinolones

48
Q

Interference with DNA Synthesis

MOA: Nitro group is reduced by nitroreductase leading to generation of cytotoxic compounds and free radicals that disrupt DNA that leads to bactericidal effect

A

Metronidazole

49
Q

Interference with DNA Synthesis

  • Effective in Anaerobic environments
  • For: Anaerobes, microaerophiles, protozoans, Gardnerella, C. difficile
A

Metronidazole

50
Q

Interference with RNA Synthesis

MOA: binds to DNA dependent RNA polymerase to inhibit RNA synthesis

A

Rifamycins such as Rifamin/ Rifampicin

51
Q

Interference with RNA Synthesis

Primarily for Gram (+) Organisms; 1st line of treatment for TB, prophylaxis for N. meningitidis carriers; intracellular pathogens

A

Rifamycins such as Rifamin/ Rifampicin

52
Q

Inhibits 50S Ribosome

  • Broad Spectrum
  • Toxic: Aplastic Anemia, Gray Baby Syndrome
A

Chloramphenicol

52
Q

Inhibits 50S Ribosome

MOA: inhibits translation through inhibition of elongation step; preventing attachment of AA

A

Chloramphenicol

53
Q

Inhibits 50S Ribosome

MOA: inhibits protein synthesis by binding to 23s RNA of the 50s ribosomal subunit inhibiting transfer RNA

A

Macrolides

54
Q

Inhibits 50S Ribosome

  • Clindamycin, Erythromycin
  • Mostly bacteriostatic
  • For Intracellular pathogens (can penetrate WBCs), Gr (+), Mycoplasma, Treponemes and Rickettsia
A

Macrolides

55
Q

Inhibits 50S Ribosome

  • Linezolid
  • Gr (+) and Mycobacteria
A

Oxazolidinones (synthetic)

56
Q

Inhibits 30s Ribosome

MOA: Inhibits protein synthesis by binding reversibly to the 30s ribosomal subunit

A

Tetracycline and Doxycycline

57
Q

Inhibits 30s Ribosome

Broad spectrum; bacteriostatic; also for intracellular pathogens, Mycoplasma, Spirochetes, Shigella

A

Tetracycline and Doxycycline

58
Q

Inhibits 30s Ribosome

Toxicity:
* GI irritation
* Phototoxic dermatitis
* Toxic to liver and kidney; phototoxic
* Discolored teeth and depressed bone growth

A

Tetracycline and Doxycycline

59
Q

Inhibits 30s ribosome

  • Often used together with penicillins in order to diffuse and enter bacterial cell
  • Narrow Therapeutic Index
A

Aminoglycosides

60
Q

Inhibits 30s ribosome

  • Ex. Streptomycin, gentamicin, tobramycin, amikacin, neomycin
  • Toxicity: Ototoxic, nephrotoxic
A

Aminoglycosides

61
Q

Antimycobacterial Agents

1st line drugs

A

Isoniazid, Rifampicin, Pyrazinamide

62
Q

Antimycobacterial Agents

2nd line drugs

A

Ethambutol, Streptomycin

63
Q

Antimycobacterial Agents : 1st Line Drugs

interferes with formation of mycolic acid

A

Isoniazid

64
Q

Antimycobacterial Agents : 1st Line Drugs

inhibit DNA dependent RNA polymerase

A

Rifampicin

64
Q

Antimycobacterial Agents : 1st Line Drugs

Bactericidal

A

Pyrazinamide

65
Q

Antimycobacterial Agents : 2nd Line Drugs

inhibit mycolic acid

A

Ethambutol

66
Q

Antimycobacterial Agents : 2nd Line Drugs

aminoglycoside

A

Streptomycin

67
Q

Composed of a beta-lactam drug with antimicrobial activity and a beta lactam drug without activity

A

Beta-Lactam combinations

68
Q

Effective against organisms that produce beta lactamases that are bound by the inhibitor

A

Beta-Lactam combinations

69
Q

Examples of Beta-Lactam combinations

A
  1. Ampicillin-sulbactam
  2. Amoxicillin-clavulanic acid
  3. Piperacillin-tazobactam
70
Q

Mechanism of Antibiotic Resistance

Changes that result in observably reduced susceptibility of an organism to a particular antimicrobial agent

A

Biologic Resistance

71
Q

Mechanism of Antibiotic Resistance

  • Antimicrobial susceptibility has been lost
  • Drug is no longer effective for clinical use
A

Clinical Resistance

72
Q

Mechanism of Antibiotic Resistance

  • random mutation due to certain agent
A

Environmentally Mediated Antimicrobial Resistance

73
Q

Environmentally Mediated Antimicrobial Resistance

decreased pH leads to aminoglycoside and erythromycin resistance; acidic

A

pH

74
Q

Environmentally Mediated Antimicrobial Resistance

Increased pH leads to tetracycline resistance; alkaline

A

pH

75
Q

Environmentally Mediated Antimicrobial Resistance

Decreased activity of aminoglycosides

A

Anaerobic Environment

76
Q

Environmentally Mediated Antimicrobial Resistance

Decreased activity of aminoglycosides to P. aeruginosa

A

Mg and Ca Conc.

77
Q

Environmentally Mediated Antimicrobial Resistance

Decreased activity of sulfonamide and
trimethoprim against enterococci

A

Folate metabolites

78
Q

Types of Microorganism-Mediated Antimicrobial Resistance

A
  1. Intrinsic : inherent resistance
  2. Acquired
79
Q

Mechanisms of Intrinsic Resistance

Sessile bacterial communities

A

Biofilms

80
Q

Mechanisms of Intrinsic Resistance

Irreversibly attached to solid surfaces

A

Biofilms

81
Q

Mechanisms of Intrinsic Resistance

Embedded in exopolysaccharide matrix

A

Biofilms

82
Q

Type of Resistance

Resistance of S. saprophyticus to Novobiocin

A

Intrinsic Resistance

83
Q

Type of Resistance

Resistance of Proteus, Providencia, Morganella and Edwardsiella to Polymyxins

A

Intrinsic Resistance

84
Q

Type of Resistance

  • Occurs as a result of prior exposure
  • Caused by changes ni the genetic make up
A

Acquired Resistance

85
Q

Type of Resistance

Genetically Encoded via:
- successful genetic mutation
- Acquisition of genes via gene transfer
- Combination of mutational and gene transfer

A

Acquired Resistance

86
Q

Acquired Resistance

Changes in the genes coding for the efflux pump

A

Efflux

87
Q

Acquired Resistance : Efflux gene

in Streptococcus pneumonia leading to macrolide resistance

A

mefA gene

88
Q

Acquired Resistance : Efflux gene

S. aureus and Enterococcus against macrolides

A

mrsA gene

89
Q

Acquired Resistance : Efflux gene

S.agalactiae against macrolides

A

mreA gene