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Cards In This Set
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Many antimicrobials are made naturally by...
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Bacteria or fungi
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Sources of antimicrobials are...
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Synthetic or natural antibiotics
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Antimicrobials are selectively toxic. What does that mean?
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They harm pathogen w/o harm to host.
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Major targets of antibiootics
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1) Cell Wall. 2) Plasma membrane. 3) Nucleic acid. 4) protein synthesis and enzymes that are important to bacteria and not host.
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What is the problem of antibiotic resistance?
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Many of these genes are found on plasmid. they encode for resistance against many different antibiotics.
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How can antibiotic resistance be controlled?
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Prevent mechanisms of horizontal gene transfer
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What are the mechanisms of horizontal transfer?
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Conjugation, Transformation, Transduction
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Resistance is tested by two tests and they are...
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Broth dilution test. Kirby-Bauer test.
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Describe the Broth dilution test.
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2-step approach. 1. A series of dilutions of the drug to be tested. 2. Bacteria are inoculated into each tube. Lowest dilution where there is no growth is the most effective.
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Minimum Inhibitory Concentration (MIC)
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The lowest dilution of antibiotic necessary to inhibit growth
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Minimum Bacteriocidal Concentration (MBC)
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The lowest dilution needed to kill the bacteria
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Describe the Kirby-Bauer test...
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Highly standardized test. Uses discs with specific concentrations of antibiotics. Discs placed on solid media inoculated w/ bacteria. Antibiotics will diffuse out of disc creating zones of inhibition.
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What are some characteristics of bacterial colonies
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Size, shape, margin, elevation
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Size is measure in?
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Mm
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Shape is described as...
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Circular, rhizoid, filamentous
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