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19 Cards in this Set
- Front
- Back
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What characteristic of drugs is defined by efficacy / activity?
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the drug has good targets in the pathogen
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What characteristic of drugs is defined by specificity / selective toxicity?
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the drug has target differences between the host and pathogens
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What is the equation for TI (therapeutic index)?
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TI = TD50 / ED50
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Cidal Antibiotics
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kill pathogens
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Static antibiotics
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prevent pathogens from growing/multiplying
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What are the four main sources of antibiotics?
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- naturally occurring
- synthetic - semi-synthetic - recombinant pathways |
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What is this classes example of a narrow spectrum antibiotic?
Why? |
Isoniazid
- targets mycobacteria (those that make mycolic acid) |
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What are this classes examples of broad spectrum antibiotics?
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amoxicillin
tetracycline chloramphenicol |
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What is this classes example of a very broad spectrum antibiotic?
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metronidazole
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What five factors are used to select an antibiotic?
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1. Identification of infecting microbe
2. Determination of susceptibility 3. Host factors 4. Infection Site factors 5. Pharmacodynamic parameters |
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What are the four methods of antibiotic susceptibility testing?
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1. serial dilutions
2. disk diffusion 3. E-test 4. Direct determination |
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Minimum Inhibitory Concentration
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In antibiotic susceptibility testing, the smallest concentration of antibiotic that will inhibit growth
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Minimum Bactericidal Concentration
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In antibiotic susceptibility testing, the minimum level at which microbes are killed
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How is ß-lactamase activity detected?
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a chromogenic disc will change color when enzyme zctivity is present
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What are reasons to use an empiric broad-spectrum antibiotic?
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- medical emergency
- causative microbe unknown - antibiotic susceptibility unknown - multiple microbes potentially involved |
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What are the reasons to use multidrug antibiotic therapy?
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- broaden coverage/spectrum
- potential synergism b/t antibiotics - overcome possible resistance - avoid development of new resistance |
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What are the reasons to use a narrow-spectrum antibiotic?
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- causative microbe known
- susceptibility to antibiotic known - reduce development of new resistance - reduce damage to normal microbiota - reduce toxicity for host - economical |
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What are the five microbes associated with AAD (antibiotic-associated diarrhea)?
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- C. diff (main cause)
- Staph aureus - Clostridium perfringens - Candida albicans - mixed infection |
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C. diff:
Type of microbe: aerobe/anaerobe, gram +/-, shape Locations found Where is there a higher carriage rate? |
anaerobic gram-positive rod
found in soil, water, gut of ~5% of humans. very stable spores in homes, hospitals carriage rate is higher in hospitals |
