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23 Cards in this Set
- Front
- Back
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Broad spectrum?
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Kill a wide spectrum of bacteria. Gram positive and negative. Bigger chance of side effects.
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Narrow spectrum?
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Kill a narrow spectrum of bacteria. Gram positive or negative.
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What is Bactoprenol and what does it do?
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protein that transports cell wall subunits (NAM & NAG) from inside of cell to outside; the "truck"
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What are penicillin binding proteins?
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link the subunits (NAM & NAG) together into the wall; the "worker"
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What do B-Lactams work?
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bind to transpeptidases & carboxypeptidases and inhibit there function; prevent cross-linking; they are penicillin binding proteins
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What bacteria are not affected by B-lactams?
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Cell wall-free forms (mycoplasmas and L-forms); early generation of the drugs were only effective on Gram positive but newer drugs work on gram negative as well
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What is a common mechanism for resistance of B-lactam?
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beta-lactamase
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How does one alter the B-lactam structure?
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alter the r group
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How much of the population is allergic to penicillin?
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20% of the population
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What antibiotics are in the B-lactam class?
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Cephalosporin; penicillin; amoxicillin
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What is Clavulanic acid?
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B-lactamase inhibitor; given with amoxicillin in augmentin
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What is a major method to produce resistance to B-lactams?
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Reduce PBP affinity; mutation in strep; acquisition in staph; changing of PBP used; can also lose porins in outer membrane (minor)
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What are glycopeptides?
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Vancomycin; inhibit cross-linking by binding D-ala-D-ala; not effective against Gram-negative because they are too large to pass through porins; has to be given IV
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What is a common mechanism of resistance to glycopeptides?
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changing the terminal D-ala with D-lac
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What is fosphomycin?
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Blocks conversion of glucosamine to muramic acid (NAM); "factory shutdown = no bricks"
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What is cycloserine?
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acts as D-alanine analog which prevents NAM production; factory shutdown
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What is Bacitracin?
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interferes with the transfer of NAM and NAG across the membrane; used topically to inhibit gram-positives; shuts down the truck
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How do Protein synthesis inhibitors work?
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bind ribosomal RNA
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Which drugs bind to the 30s?
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Tetracyclines and aminoglycosides
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Which drugs bind to 50s?
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Macrolides; chloraphenicol; lincosamides; oxazolidinones; streptogramins
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What are aminoglycosides?
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amino containing sugar; bind irreversibly (bactericidal) to 30s preventing fmet-tRNA binding; includes streptomycin, gentamicin, and tobramycin; nephrotoxic and ototoxic (8th); resistance from drug modification from enzymes
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What are tetracyclines?
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4 six member rings; bind reversibly (bacteriostatic) to 30s; broad spectrum; doxycycline and minocycline; most resistance is due to efflux; interferes with bone development and teeth; no use under 8 years old
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What is chloramphenicol?
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modified nitrobenzene ring; binds reversibly to the 23s of the 50s subunit; primarily resistance from acetylation of OH group by CAT (chloramphenicol acetyl transferase); bone marrow suppressant; 1/30000 patients Aplastic anemia and death
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