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26 Cards in this Set
- Front
- Back
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Antisepsics |
Applied to skin/tissue surface |
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Disinfectants |
Applied on inaminate surfaces beach, chlorine, H peroxide, ethanol |
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Antimicrobial |
Bacteriocidal or bacteriostatic |
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Mechanism of action of antiseptics and disinfectants |
non-specific effects, thus high toxicity. 2. strong oxidants which inactivate proteins and damage DNA: H peroxide, chlorine 3. Disrupts cell membranes: detergents, quaternary ammonium compounds. |
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Quinolones |
DNA gyrase |
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Beta-lactams |
Cell-wall synthesis |
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Aminoglycosides |
30S tRNA translocation Target gram - |
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Tetracycline |
30S tRNA delivery |
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Macrolides |
50S blocks exit on ribosome |
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Chloramphenicol/lincozamide |
50S inhibits peptidyl transferase center. |
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beta-lactam |
binds to PBP (penicillum binding protein) inhibits transpeptidase activity. |
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beta-aminoglycosides |
-for multi-drug resistant gram negative infections -only injectable or intravenous --> high toxicity.. |
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Oxazolidinone |
1. first synthetic compound 2. inhibits 50S. |
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MIC |
minimal inhibitory concentration measure the diameter of inhibition
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Mechanisms of antibiotic resistance |
1. Efflux of drugs 2. Target mutation 3. Target modification 4. Drug modification 5. Drug degradation - encoded by G- bacteria (pseudomonas) or plasmid borne horizontal gene transfer. |
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Efflux drug |
G-: tetracycline, macrolides |
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Target mutation |
- gyrB topoisomerase --> quinolone resistance |
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Drug modification |
Aminoglycoside: AMP, Phosphorylation, Acetylation |
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Drug degradation |
Beta lactamase -encoded in some G- bacteria and can be plasmid borne -ESBL cleave cephalosporin -metallo-beta-lactamase cleaves carbapenems |
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Horizontal gene transfer |
1. bacterial transformation (picks up loose DNA in environment) 2. Bacterial transfuction (through bacteriophage_ 3. Bacterial conjugation (interspecies, allow multiple resistance gene through plasmid) |
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Human behavior in antibiotic resistance |
1. antibiotic overuse 2. antibiotic misuse -insufficient length of treatment -improper indications |
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Overcome antibiotic resistance |
1. new antibiotics 2. inactivating resistance mechanisms - disable antibiotic degrading or modifying enzyme 3. change behavior |
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S. aureus and MRSA |
1. beta-lactams 2. Vancomycin 3. daptomycin, linezolid |
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mecA gene |
encodes PBP2', a low affinity PBP protein( resistance) |
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CA-MRSA |
community associated, multiple mec types, multiple resistance and virulence genes. |
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New-Dehli metallo-betalactamase |
NDM-1 cleaves carbapenems plasmid encoded in Gram - |
