Term
| ideal antimicrobial agents |
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Definition
-only destroys the offending microbe
-targets microbial processes that are not present in the host
-have limited or no toxicity to the host
-long half-life of the drug
-both oral and intravenous formulation
-have little effect on normal host flora
-not be susceptible to microbial resistance mechanisms |
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Term
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Definition
only effective against bacteria
-many common classes of antibiotics based on their mechanism of action |
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Term
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Definition
-penicillins
-cephalosporins
-monobactams
-carbepenems
-glycopeptides
-lipopetides |
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Term
| dna synthesis and maintenance |
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Definition
-sulfonamides and trimethoprim
-quinolones |
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Term
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Definition
| bacteria make cell wall with peptidoglycan, repeating structure of n-acetylmuramic acid and n-acetylglucosamine |
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Term
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Definition
discovered by alexander fleming while woring on isolating lysozyme from staphylococcus....floor below him another person was working with penicillin...while on vaca, he lefthis cultures out and on return noticed no bacteria
-beta lactamases can render the penicillin ineffective...but if the structure of penicillin is changed, can resist destruction |
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Term
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Definition
-beta lactamases do not degrade vanocomycin
-not all bacteria use d-alanine-d-alanine on their cell wall precursors
-if bacteria exchange genes to synthesize a different type of cell wall precursor then they would be vancomycin resistant |
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Term
| protein synthesis inhibition |
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Definition
-30s ribomosomes --aminoglycosides and tetracyclines (problems with toxicity)
-50s ribosomes --erythromycins, clindamycin, oxazolidinones |
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Term
| resistance to protein synthesis inhibitors |
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Definition
-alter ribosomal binding site
-pump antibiotics out of cell |
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Term
| dna synthesis and maintenance |
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Definition
-quinolones alter dna gyrase-responsible for folding and unfolding the dna
-quinolons target two enzymes: -dna gyrase -topoisomerase iv (may be sensitive to drugs like levoflaxacin but provide a background for the 2nd hit and resistance |
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Term
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Definition
-structural analogs of PABA that competitively inhibit dihydropteroate synthase.
-organsims sensitive to these require extracellular PABA in order to form dihydrofolic acid which is essential in the production of nucleic acids.
-mammalian cells lack the enzymes required for folate synthesis and depond upon exogenous sources of folate; therefore, they are not susceptible to sulfonamides |
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