Microbiology Antibiotics 2 Flashcards

1
Q

Fluoroquinolones example

A
  • Ciprofloxacin
  • Levofloxacin
  • Moxifloxacin
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2
Q

Aminoglycosides example

A

• Gentamicin

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3
Q

Glycopeptides example

A
  • Vancomycin

* teicoplanin

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4
Q

Macrolides example

A
  • Erythromycin

* Clarithromycin

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5
Q

Tetracyclines example

A

• Minocycline

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6
Q

Fluoroquinolones: Used

A

Mainly used in hospital to treat Gram negative infection and lower resp tract infections

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7
Q

Fluoroquinolones: Action

A

By inhibiting DNA gyrase,

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8
Q

Fluoroquinolones: Resistance

A

Increasingly common – mainly target site modification but also efflux pumps.

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9
Q

Fluoroquinolones:Absorption

A

Good oral bioavailability so po often as good as iv

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10
Q

Fluoroquinolones:Distribution

A

Wide tissue distribution (2-3 L/Kg)

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11
Q

Fluoroquinolones:Excretion and metabolism

A
Excretion y metabolism (ciprofloxacin, moxifloxacin)
Renal clearance (Ciprofloxacin, moxifloxacin, levofloxacin)
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12
Q

Fluoroquinolones: Side effects

A
Generally safe:
•	Rashes/phototoxicity
•	Tendenitis and rupture
•	GI upset
•	OTC prolongation (moxifloxacin) - (more likely to have ventricular tachy arrhythmia)
•	Hepatotoxicity
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13
Q

Spectrum-ciprofloxacin: targets

A
  • Aerobic Gram negative bacterial (coliforms, Pseudomonas, gonococci, H. influenza, atypical chest pathogens (legionella,mycoplasma, chlamydia))
  • Border line activity against S.aureus and streptococci
  • Not active against anaerobes
  • Some activity against M. tuberculosis
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14
Q

Spectrum – moxifloxacin: Target

A
  • Much improved activity versus Staphylococci and Streptococci
  • Poor activity vs. P.aeruginosa, better activity against anaerobes
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15
Q

Spectrum – moxifloxacin:Indications

A
  • Community acquired chest infections (moxifloxacin/levofloxacin)
  • UTI/acute pyeonephitis (ciprofloxacin, levofloxacin) NB resistanct
  • Intraabdominal infection (+ metronidazole)
  • Bone/joint infection
  • Oral therapy of P.aeruginosa (ciprofloxacin)
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16
Q

Aminoglycosides: Action

A

Inhibiting of protein synthesis at ribosoms

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17
Q

Aminoglycosides: Resistance by

A

Enzymes (aminoglycoside monitoring enzymes) but rare

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18
Q

Aminoglycosides: Absorption

A

Intravenous/Im only

Poor oral absorption

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19
Q

Aminoglycosides: Distribution

A

Modest tissue penetration – concentrated in the kidney and ears (toxicity)

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20
Q

Aminoglycosides:Excretion

A

Renal excretion – accumulation in renal failure, no metabolism

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21
Q

Aminoglycosides:Examples

A

Gentamicin
Tobramycin
Amikacin IV

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22
Q

Aminoglycosides: Reduced use because

A

Toxicity requires therapeutic drug monitoring

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23
Q

Aminoglycosides: Antimicrobial spectrum

A

Broad Gram negative activity
Coliform
P.aeruginosa
No anaerobic activity

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24
Q

Aminoglycosides: Indications

A
  1. In combination therapy for intra abdominal infection
  2. In combination therapy for infective endocarditis
  3. In combination therapy for neutropaenic sepsis
  4. In combination therapy for neonatal sepsis (pen/fluclox)
  5. In combination therapy for P. aeruginosa infection (Cf)
  6. In combination therapy for S. aureus
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25
Q

Aminoglycosides: Side effects

A
  1. Nephrotosicity (reversible)

8. Otototoxicity (irreversible)

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26
Q

Glycopeptides Example

A

Vancomycin

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27
Q

Glycopeptides Absorption

A

Intravenous hospital only, wide use to treat multi resistant Gram positive infection, especially MRSA

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28
Q

Glycopeptides Action

A

Inhibiting cross linking of bacterial cell wall

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29
Q

Glycopeptides Resistance

A

Rare except in Enterococci and due to altered target side (enterococci, Staphylococci) and permeability (Staphylococci)

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30
Q

Glycopeptides Excretion

A

Renal

31
Q

Glycopeptides Metabolism

A

None

32
Q

Glycopeptides Absorption note

A

Used for C.diff as although it has no oral bioavailabiity this doesn’t matter as it can target the gut without being absorbed.

33
Q

Glycopeptides Side effects

A

Nephrotoxicity (around 10%) increased by use of other
Nephrotoxicity agents (gentamicin, frusemide)
Otoxicity very rare
Red man syndrome 9vancomycin) – histamine release mean the does is given too quickly
Thrombocytopenia (teicoplanin in big doses)

34
Q

Glycopeptides Requires

A

Therapeutic drug monitoring

35
Q

Glycopeptides Spectrum

A

Broad Spectrum: Active against nearly all gram positive bacteria, expecially multi resistant strains.
Not activie against Gram negative bacteria

36
Q

Glycopeptides Indications

A
  • MRSA infection
  • Clostridium difficle associated diarrhoea (CDAD) as 2st line treatment
  • Multiresistant Gram positive infection i.e. coagulase negative Staphylococci, Cornebacteria, Enterococci
  • Prosthetic infection (Line, joint tc
  • Penicillin allergy
37
Q

Macrolides: Examples

A

Erythromycin/clarithromycin

38
Q

Macrolides: Absorption

A
  • IV and po agents widely used in hospital and community to treat lower respiratory tract infection and in penicillin allergy.
  • Reasonable bioavailability
  • Good oral absorption
39
Q

Macrolides: Action

A

Inhibition of protein synthesis at ribosome

40
Q

Macrolides: Resistance

A

Common, due to target modification

41
Q

Macrolides: Distribution

A

Good tissue penetration

42
Q

Macrolides: Excretion

A

Biliary and renal

43
Q

Macrolides: Side effects

A

Nausea and GI upset, especially erythromycin (pharmacological effect on stomach motility)

44
Q

Macrolides: Spectrum

A
  1. Active against gram positive organism i.e. s. aureus ( not MRSA), Streptococci, resistance 10-20%
  2. Active against atypical respiratory pathogens legionella, Mycoplasma, chlamydia
  3. No activity against Gram negatives except for campylobacter
45
Q

Macrolides: Indications

A
  • Skin/soft tissue infection if penicillin allergic
  • Community acquired pneumonia
  • Campylobacter infection
  • H. Pylori
  • (Staph and strep)
46
Q

Tetracycines: Examples

A

Minocycline

Doxycycline

47
Q

Tetracycines: Used in

A

Primary Care to treata acne

In hospital as oral therapy for MRSA

48
Q

Tetracycines: Action

A

Inhibits synthesis at ribosome

49
Q

Tetracycines: Resistance

A

Relatively common due to efflux pumps and target site modification

50
Q

Tetracycines: Contraindicated in children as

A

Concentrated in bones/teeth, bind to calcium

51
Q

Tetracycines: Absorption

A

Only orally

52
Q

Metronidazole: Absorption

A

Good bioavailability

Available as iv/po

53
Q

Metronidazole: Widely used to

A

Treat anaerobic infection

54
Q

Metronidazole: Action

A

Disrupts DNA

55
Q

Metronidazole: Distribution

A

Wide tissue distribution

56
Q

Metronidazole: Resistance

A

Very rare in anaerobes

57
Q

Metronidazole: Safety concerns

A

Early pregnancy

Disulphuram-like reaction with alcohol, rare peripheral neuropathy on long therapy (Augments hangover)

58
Q

Trimethoprim: Absorption

A

Po/Iv only with sulphamethoxazole (co-trimoxazole) to treat PCP

59
Q

Trimethoprim: Used to treat

A

Uncomplicated UTI

60
Q

Trimethoprim: Action

A

Inhibits Folate metabolism by inhibition of dihydrofolate reductase

61
Q

Trimethoprim: Resistance

A

By over production or modification target enzyme enzyme (20% E.coli)
Renal excretion

62
Q

Linezolid Which forms is available for clinical use

A

Oxazolidinase

63
Q

Linezolid Active against

A

A wide range of gram positive bacteria including multi-resistant strains (MRSA, VRE)

64
Q

Linezolid Absorption

A

Good bioavailability

65
Q

Linezolid Penetration

A

Moderate/good tissue distribution

66
Q

Linezolid Excretion/metabolism

A

None enzymatic degradation

Breakdown products renally excreted

67
Q

Daptomycin: Absorption

A

Only lipopeptide antibiotic available. Iv only.

68
Q

Daptomycin: Active against

A

A wide range of gram positive bacteria including multi resistant strains (MRSA, VRE)

69
Q

Daptomycin: Absorption

A

Poor oral absorption

IV only

70
Q

Daptomycin: Exrection

A

Renal

71
Q

Daptomycin: Penetration

A

Poor lung penetration

72
Q

Daptomycin: Toxicity

A

Muscle toxicity

73
Q

Daptomycin: Second line for

A

Gram positive infection

74
Q

Daptomycin: Not suitable for

A

Use in lung infection