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17 Cards in this Set
- Front
- Back
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What is meant by antibiotic stewardship? |
•Reduce antibiotic consumption
•Restrict worst offender agents •Promote logical antibiotic choices •Limit “co-lateral damage” |
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What s meant by guided therapy? Give an example |
- Depends on identifying cause of infection and selecting agent based on sensitivity testing - cystits or mild wound infections |
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What is meant by empirical therapy? Give an example. |
–Best (educated) guess therapy based on clinical/epidemiological acumen –Used when therapy cannot wait for culture –Sepsis and Meningitis |
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What is mean by prophylactic therapy? Give an example |
preventing infection before it begins –HIV, Transplantation |
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List 6 ideal characteristics for an antibiotic |
- highly toxic to bacteria causing infection - penetrates the area of infection - convenient administration - non-toxic to patient - limited damage to resident bacteria - low propensity for resistance |
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Which types of antibiotic are most suitable for guide and empirical therapy |
guided: narrow spectrum empirical: broad spectrum |
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Define bactereicidal and bacteristatic |
bactericidal: kills bacteria bacteristatic: inhibits growth or reproduction |
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List 4 targets on a bacterial cell for antibiotics and give an example of each |
- ribosome: macrolides and aminoglycosides - DNA: quinolones - metabolsim: trimethroprim - cell wall: penicillins and glycopeptides |
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Give an overview of penicillins (beta lactams) and their mechanism of action |
- broad spectrum (though variable potency) with low toxicity - can cause type I-IV hypersensitivities and other adverse effects - has beta-lactam ring which targets enzymes in the cell wall called penicillin binding protiens - prevents cross-linking of the cell wall (wall synthesis) - leads to death through osmotic instability or autolysis |
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What are the potential adverse effects of beta lactams |
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What is the mechanism of action of glycopeptides (e.g. vancomycin)? What is its main use? |
-bind toprecursors of cell wall synthesis which leads to interference of thepenicillin-binding protein (PBP) enzymes such as transpeptidases to incorporate the precursors into the growing cell wall. - With this,cell wall synthesis stops and cell death often follows. - mainly for MRSA |
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What is the MOA of macrolides |
- protein synthesis inhibitor -bind to and inhibit CYP-3A4 - prevent peptide chain extension - bacteristatic |
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What is the MOA of aminoglycosides? What are some of its adverse effects |
- reversibly bind to 30S ribosome - bacteristatic - also has a bactericidal effect at high concentrations due to poorly understood effect on cell membrane - can cause nephrotoxicity, ototoxicity (hearing, loss of balance, disturbed vision) and neuromuscular blockade |
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What is the MOA of quinolones? |
- bactericidal and broad spectrum - inhibit bacterial DNA gyrase needed for replication |
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What is the MOA of trimethoprim? |
- bacteristatic - inhibit folate metabolism preventing DNA synthesis - can cause renal toxicity |
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Give three mechanisms of antibiotic resistance |
- mutations at target site - inactivating enzymes - reduced access e.g. efflux of reduced permeability |
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How has resistance to beta lactams developed? Can these be countered? |
- mutation of targets - penicillin binding proteins - production of beta-lactamases: enzymes that lyse and deactivate beta lactams - beta lactamase inhibitors can be co-administered, increasing spectrum and potency |
