Micro exam chp 10

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Micro exam chp 10
2013-06-11 21:46:02
Micro chp 10

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  1. Methods of Antimicrobial Action:
    • Selective Toxicity
    • Inhibition of Cell Wall(beta lactam ring interferes with NAG/NAM cell wall)
    • Inhibition of Protein synthesis(6 pathways) include:
    • 1.Distorts 30S subunit
    • 2.Blocks docking site of tRNA
    • 3.Blocks peptide chains from forming
    • 4.Binds 50S subunit to prevent mRNA from working
    • 5.Brings in antisense nucleic acids that block ability to translate amino acids
    • 6.Binds to codon and prevents 50S unit from working
    • Disruption of cytoplasmic membranes(by targeting ergosterols that pop holes in membrane)
    • Inhibition of Metabolic Pathways(sulfa drugs-blocks conversion of PABA in enzymes)
    • Inhibition of Nucleic acid synthesis(Uses analogs instead of nucleotides, more efficent in viruses)
    • Prevention of virus attachment
  2. Routes of administration:
    • Oral: low concentration, cheap and easy; people forget dosesĀ 
    • Intramuscularly: high concentration in system quickly, but quickly metabolized
    • Intravenously: direct line, very severe infection
    • Topical
  3. Mechanisms of Resistance:
    • May produce an enzyme that destroys or deactivates drug(b-lactamase)
    • May slow or prevent entry of drug into cell
    • May alter receptor for drug so it cant bind
    • Mayb alter metabolic pathway or abandon that step altogether
    • May pump drug out of cell before it can act
  4. Retarding Resistance:
    • Maintain high levels of antibiotic for long period
    • Use antimicrobial agents in combination(for superbugs)
    • Limit use of antibiotics to necessary cases
    • Develop second generation drugs, altering existing drugs