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15 Cards in this Set
- Front
- Back
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What is the goal of antimicrobial chemotherapy?
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Administer a drug to an infected person that destroys the infective agent without harming the host's cells.
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How are antimicrobial drugs produced?
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Antimicrobial drugs are produced either synthetically or from natural sources.
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Define antibiotics & their genera
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Antibiotics are common metabolic products of aerobic bacteria and fungi.
-Bacteria in genera Streptomyces & Bacillus -Molds in genera Penicillium & Cephalosporium |
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Define antagonism
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By inhibiting the growth of other microorganisms in the same habitat (antagonism), antibiotic producers presumably enjoy less competition for nutrients and space.
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Antimicrobial drugs should be selectively toxic what does this mean?
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Drugs should kill or inhibit the growth of microbes without simultaneously damaging host tissues.
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Describe what happens as the characteristics of the infectious agent becomes more similar to the vertebrate host cell
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Complete selective toxicity becomes more difficult to achieve and more side effects are seen.
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What are the 5 mechanisms
of drug action? |
1. Inhibition of cell wall synthesis
2. Breakdown of cell membrane structure or function 3. Inhibition of nucleic acid synthesis, structures and functions of DNA and RNA 4. Inhibition of protein synthesis 5. Blocks on key metabolic pathways |
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How are antimicrobial drugs classified?
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Spectrum= Range of effectiveness
= Range of activity of a drug |
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Define narrow-spectrum
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Narrow-spectrum- effective against a limited range of microbes (small range of cell types)
- target a specific cell component that is found only in certain microbes |
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Define broad-spectrum
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Broad-spectrum drugs have the greatest range of activity.
-target cell components common to most pathogens (ie, ribosomes) |
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What do the cell walls of most bacteria contain?
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A rigid girdle of peptidoglycan
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Which drugs block the synthesis of peptidoglycan and what does this cause?
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Penicillins and cephalosporins block the synthesis of peptidoglycan causing the cell wall to lyse (bactericidal)
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It is important to note that most antibiotics are ....
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Active on young, growing cells
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Which antibiotic does not penetrate the outer membrane and is less effective against Gram-negative bacteria?
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Penicillin
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Broad-spectrum penicillins and cephalosporins can...
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cross the cell walls of Gram-negative bacteria
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