Flashcards in Microbiology Antibiotics 2 Deck (74)
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1
Fluoroquinolones example
• Ciprofloxacin
• Levofloxacin
• Moxifloxacin
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Aminoglycosides example
• Gentamicin
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Glycopeptides example
• Vancomycin
• teicoplanin
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Macrolides example
• Erythromycin
• Clarithromycin
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Tetracyclines example
• Minocycline
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Fluoroquinolones: Used
Mainly used in hospital to treat Gram negative infection and lower resp tract infections
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Fluoroquinolones: Action
By inhibiting DNA gyrase,
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Fluoroquinolones: Resistance
Increasingly common – mainly target site modification but also efflux pumps.
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Fluoroquinolones:Absorption
Good oral bioavailability so po often as good as iv
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Fluoroquinolones:Distribution
Wide tissue distribution (2-3 L/Kg)
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Fluoroquinolones:Excretion and metabolism
Excretion y metabolism (ciprofloxacin, moxifloxacin)
Renal clearance (Ciprofloxacin, moxifloxacin, levofloxacin)
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Fluoroquinolones: Side effects
Generally safe:
• Rashes/phototoxicity
• Tendenitis and rupture
• GI upset
• OTC prolongation (moxifloxacin) - (more likely to have ventricular tachy arrhythmia)
• Hepatotoxicity
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Spectrum-ciprofloxacin: targets
• 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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Spectrum – moxifloxacin: Target
• Much improved activity versus Staphylococci and Streptococci
• Poor activity vs. P.aeruginosa, better activity against anaerobes
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Spectrum – moxifloxacin:Indications
• 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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Aminoglycosides: Action
Inhibiting of protein synthesis at ribosoms
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Aminoglycosides: Resistance by
Enzymes (aminoglycoside monitoring enzymes) but rare
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Aminoglycosides: Absorption
Intravenous/Im only
Poor oral absorption
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Aminoglycosides: Distribution
Modest tissue penetration – concentrated in the kidney and ears (toxicity)
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Aminoglycosides:Excretion
Renal excretion – accumulation in renal failure, no metabolism
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Aminoglycosides:Examples
Gentamicin
Tobramycin
Amikacin IV
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Aminoglycosides: Reduced use because
Toxicity requires therapeutic drug monitoring
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Aminoglycosides: Antimicrobial spectrum
Broad Gram negative activity
Coliform
P.aeruginosa
No anaerobic activity
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Aminoglycosides: Indications
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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Aminoglycosides: Side effects
7. Nephrotosicity (reversible)
8. Otototoxicity (irreversible)
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Glycopeptides Example
Vancomycin
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Glycopeptides Absorption
Intravenous hospital only, wide use to treat multi resistant Gram positive infection, especially MRSA
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Glycopeptides Action
Inhibiting cross linking of bacterial cell wall
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Glycopeptides Resistance
Rare except in Enterococci and due to altered target side (enterococci, Staphylococci) and permeability (Staphylococci)
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