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19 Cards in this Set
- Front
- Back
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How do beta-lactam antibiotics kill bacteria?
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The bind to penicillin-binding proteins on inner cell membranes and activate endogenous bacterial autolysins that cause the cells to lyse.
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What is the most common form of resistance to beta-lactam antibiotics among nosocomial gram-negative organisms?
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formation of beta-lactamase enzymes
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Ceftazidine can induce production of beta-lactamases in what bacteria?
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1) Pseudomonas
2) enterobacter spp 3) citrobacter spp |
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Name three beta-lactam/beta-lactamase inhibitor combinations
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1) Ampicillin-sulbactam
2) ticarcillin-clavulanate 3) piperacillin-tazobactam |
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What do carbapenems have the widest spectrum of all the beta-lactam antibiotics?
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because they have special stereochemical characteristics that make them resistant to most beta-lactamases.
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What beta-lactamase inhibitor has the greatest potency?
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tazobactam
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What monobactam binds exclusively to PBPs of gram-negative organisms?
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Aztreonam
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How aminoglycosides work?
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They interfere with bacterial protein synthesis during aerobic metabolism.
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How do fluoroquinolones work?
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They affect the genetic controls of most gram-negative, gram-positive and some intracellular bacteria by inhibiting DNA gyrase.
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What is the mechanism by which bacteria become resistant to fluoroquinolones?
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They have mutations in the DNA gyrase gene that alters the target portion of the fluoroquinolone.
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What type of antibiotic is Vancomycin?
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A glycopeptide.
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What is Vancomycin's mechanism of action?
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It inhibits cell wall synthesis of gram-positive organisms.
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Name three macrolides.
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1) Erythromycin
2) Azithromycin 3) Clarithromycin |
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What is mechanism of action of the macrolides?
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inhibit bacterial growth by interfering with protein synthesis and are bacteriostatic. Clindamycin acts via the same mechanism
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What is the mechanism of action of clindamycin?
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Same as the macrolides: inhibit bacterial growth by interfering with protein synthesis.
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What macrolides have a broader spectrum than erythromycin and why?
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Clarithromycin and azithromycin because they can penetrate the cell membranes of gram-negative bacilli
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How do sulfonamides work?
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Sulfonamides are bacteriostatic and inhibit enzymes involved in the formation of folic acid and act synergistically with trimethoprin to block purine synthesis
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What is bactrim?
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trimethoprin-sulfamethoxazole - a combo of sulfonamide and trimethorpin
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What percentage of ICU gram-negative flora is bactrim resistant?
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40%
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