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31 Cards in this Set
- Front
- Back
What are Anti-infective Drugs? |
Drugs used to combat infections caused by micro-organisms |
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How are anti-infective drugs identified? |
- Culture and sensitivity of the organism - Differential staining of the organism |
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Organisms to be identified |
- viruses - chlamydia - rickettsia - bacteria - fungi |
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Define antibiotics |
Agents that act against bacteria |
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Antibiotic classifications |
- Identification through staining Gram "-" or Gram "+" - Identification through oxygen requirements Aerobes (need 02) or Anaerobes (no 02 requirements) |
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What color do Gram Positive stain? |
blue or purple |
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What color do Gram Negative stain? |
pink or red |
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Why use classifications? |
Classifications help to characterize the spectrum of action of an antibiotic |
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Mechanism of action for antibiotics |
- bactericidal - bacteriostatic * can be both depending on dosing |
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action of bactericidal antibiotics |
Kills bacteria outright |
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action of bacteriostatic antibiotics |
Inhibits growth and slows reproduction of bacteria |
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Define Resistance |
Mutation of a bacteria, making it lose susceptibility to a given antibiotic; I.E. super-bug |
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Define Susceptibility |
- In Vitro: Kirby Bauer procedure & Broth dilution (Lab) - In Vivo: Actual effects in patients - how well the antibiotic counteracts the bacteria * Effects are not always the same in vivo as in vitro |
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Considerations prior to antibiotic use |
- do not use for mild infections
- use only in individuals at risk for severe infection - asepsis technique - culture and sensitivity - fulfill therapeutic dosing (against hardier organisms) - maintain safety of food supply (including withdrawal time in food supply animals) |
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Classes of Antibiotics |
- Beta-Lactams (Penicillins, Cephalosporins, Carbapenems) - Tetracyclines - Aminocyclitols - Quinolones - Macrolides/Lincosamides - Sulfonamides - Chloramphenicol/Florfenicol - Polypeptides (topical) - Nitrofurans (topical) - Metronidazole (oral, IV) |
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Classes of Antibiotics (Others) |
- Nitrofurantoin - Rifampin - Novobiocin - Potassium Iodide |
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Beta Lactams |
- Bactericidal - Have Beta Lactam ring in chemical structure - Penicillin: first modern antibiotic by Alexander Fleming |
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Many generations of Penicillins differing in |
- administration forms - duration of action - spectrum (gram +/-) - resistance to B-lactamase |
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What is B-lactamase? |
An enzyme produced by some bacteria that renders the antibiotic ineffective |
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Penicillin - Pharmacokinetics |
- variable absorption through the GI tract (primarily stomach and small intestines - rapid distribution when injected (IM) - excreted via kidneys |
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Penicillin - Pharmacodynamics |
- bind to cell wall, increasing osmotic pressure and causing bacteria to burst - inactivated by B-lactamase (penicillinase - bacterial enzyme) |
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What is the spectrum of Penicillins? |
Spectrum is variable |
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Penicillin spectrum ranges |
- narrow - broad spectrum - potentiated - probenecid - B-lactamase resistant |
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Narrow Spectrum Penicillins |
Pen-G, Pen-V (no use in birds, small animals, or food animals; not given SQ) |
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Broad Spectrum Penicillins |
- Ampicillin (inj.) - Amoxicillin (tab. or reconstituted liq.) - TX lyme - Carbenicillin |
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Potentiated |
- Amoxicillin and Clavulonic Acid - Ticarcillin and Clavuloate |
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Probenecid |
Inhibits tubular secretions of penicillins (Given with penicillins to decrease the concentration in body tissues) |
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Beta-Lactamase Resistant |
- Ampicillin/Sublactam - Methicillin - Cloxacillin - Dicloxacillin - Floxacillin - Oxacillin |
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Adverse side effects of penicillin |
- vomiting and diarrhea - urticaria / hives - Anaphylactic shock (with inj.) - Neurotoxicity with extended use ALLERGIC REACTION to any penicillins = reaction to ALL penicillins and cephalosporins |
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Considerations with penicillin use |
- Acts synergistically with aminoglycosides (can give 2 abx that improve the effects of each other) - Pre-slaughter withdrawal times - Allergic risks to technicians |
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Carbapenems |
- Beta-Lactam antibiotics - Inhibit bacterial cell wall synthesis (wide range of activity) - Act as bactericidal - Used in equine and small animal [Imipenam] {Cilastatin} |