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54 Cards in this Set
- Front
- Back
bacteriostatic
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able to reversibly inhibit essential metabolic processes,
but not kill, susceptible bacteria |
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MIC =
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minimum inhibitory concentration
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minimum inhibitory concentration
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lowest concentration of a given ABS that prevents growth under standardized conditions
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MBC
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minimum bacterial concentration
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minimum bacterial concentration
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lowest concentration of a given ABS required to kill 99.9% of the bacteria in a suspension in a given time
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breakpoint
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concentration of an ABS that can be achieved in the bloodstream with optimal therapy
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spectrum
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range of genera and species against which an ABS is effective
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TI
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therapeutic index
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therapeutic index
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ratio of TOXIC DOSE
to THERAPEUTIC DOSE (should be greater than 1!) |
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5 desirable properties in an antimicrobial
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selective toxicity
bactericidal vs. bacteriostatic no development of resistance not allergenic soluble, stable and active in body fluids |
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5 bacterial processes inhibited by ABS
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cell wall synthesis
protein synthesis nucleic acid metabolism membrane function key enzymatic reactions |
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5 mechanisms of resistance
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access
target site modification bypass binding inactivation |
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innate/intrinsic resistance
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all members of a species are resistant due to some specific quality
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acquired resistance
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an individual strain develops resistance due to mutation or acquisition of resistance genes
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5 organisms of concern wrt ABS resistance
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S. aureus
E. faecalis Strept. pneumoniae N. gonorrhoeae S. enterica |
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3 methods of antimicrobial susceptibility testing
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broth dilution method
agar dilution method disk diffusion method (Kirby-Bauer) |
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3 cell wall synthesis inhibitors
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beta-lactams
vancomycin bacitracin |
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4 types of beta-lactams
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penicillins
monobatams carbapenems cephalosporins |
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mechanism of action for beta-lactam ABS
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blocks transpeptidation reaction necessary for the formation of peptidoglycan crosslinks
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molecular targets of beta-lactam ABS
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penicillin binding proteins
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what type of ABS requires actively growing cells to be effective?
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beta-lactams (penicillins)
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Provided organism is susceptible, what class of ABS is the drug of choice?
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beta-lactams
high TI & bactericidal |
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beta-lactamase inhibitors
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clavulanic acid
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clavulanic acid
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beta-lactam that acts as a suicide inhibitor of beta-lactamase
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what ABS is effective only against gram-positive organisms?
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VANCOMYCIN
BACITRACIN effective only against gram-positive organisms |
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mechanism of action for vancomycin
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blocks cell wall synthesis
blocks release of peptidoglycan precursor |
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Vancomycin resistance is due to___
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target site modification
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what type of molecule is vancomycin
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glycopeptide
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Bacitracin is a ...
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cyclic polypeptide (mixture) ABS
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mechanism of action of bacitracin
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blocks cell wall synthesis by blocking cycling of bactroprenol carrier
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What ABS are effective only against gram negative bacteria?
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polymixin
colistin |
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mechanism of action of polymixin and colistin
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alters permeability of cell membranes by binding to LPS and phospholipids
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ABS that are very toxic nephrotoxins
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polymixin
colistin |
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mycobacterial cell wall inhibitors
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INH, ethionamid
ethambutol cycloserine |
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class of ABS that cause irreversible inhibition of protein synthesis
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aminoglycosides
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route of delivery for aminoclycosides
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poorly absorbed orally
usually given IV |
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examples of aminoglycosides
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stremptomycin
gentamycin neomycin |
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what class of ABS requires ox-phos to be actively transported into target cells?
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aminoglycosides
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mode of action for tetracyclines
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reversible inhibition of protein synthesis
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are tetracyclines bactericidal or bacteriostatic
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bacteriostatic
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common broad-spectrum bacteriostatic
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tetracycline
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mode of action for chloramphenicol
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blocks protein synthesis by inhibiting peptidyl transferase
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chloramphenicol is bactericidal or bacteriostatic?
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bacteriostatic
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chloramphenicol toxicity can can cause...
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aplastic anemia
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mode of action for macrolides and lincosamides
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reversible inhibition of protein synthesis
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examples of mocrolides/lincosamides
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erythromycin
axithromycin clindamycin lincomycin |
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T/F: macrolides are bacteriostatic and broad spectrum?
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TRUE
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class of ABS developed specifically for use against vancomycin resistant, gram-positive organisms and multi-drug resistant staph
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oxazolidinones
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Linezolid
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first oxazolidinone approved by FDA
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cirpofloxacin - what class ABS?
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quinolones
broad spectrum fluorquinolone |
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mode of action for rifampicin
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blocks DNA-dependent RNA polymerase
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what ABS class is active only against anaerobic bacteria?
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metronidazole
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2 metabolic inhibitors
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trimethoprim
sulfanoamides |
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mode of action for sulfanamides
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reversibly block steps in folic acid synthesis
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