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47 Cards in this Set
- Front
- Back
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What is an antimicrobial drug?
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chemically synthesized drugs that inhibit growth or kill microorganisms.
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Who is Paul Erlich?
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concept of selective toxicity (toxic to microbe); discovered salvarsan to fight syphilis
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Who is Gerhard Domagk?
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Found treatment for streptococci
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What are antibiotics?
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naturally created by molds and bacteria.
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Who is Alexander Fleming?
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Discovery of PCN, unable to isolate; grew colonies of staph near mold
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Who was Ernst Chain and Howard Florey?
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Purified and mass produced PCN
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Who was Selman Waksman?
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isolated antibiotic streptomycin from soil bacteria streptomyces griseus
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What are modern antibiotics?
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derive from bacteria and mold. selected strains are incubated and then extracted and purified and altered to increase stability
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What are semi-synthetic antibiotics?
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antibiotics that have been altered chemically to give new derivatives with new properties. vary by side chain
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What are the natural PCNs?
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Pen G and Pen V extracted from penicillum
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What is methicillin?
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semi-synthetic penicillinase resistant. treats s. aureus
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What is ampicillin?
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semi-synthetic broad spectrum also acid resistant
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What is amoxicillin?
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identical to ampicillin but longer 1/2 life= less doses
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What is antimicrobial selective toxicity?
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drug causes more harm to microorganisms than humans, attacks structures not found in humans
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What is therapeutic index?
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toxicity of a given drug. more selective toxic the higher the therapeutic index.
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What does a bacteriostatic do?
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rely on normal hosts immune defenses to destroy once growth has been inhibited. ie. sulfa drugs
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What does a bacteriocidal do?
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kills bacteria when host defenses cant
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What are broad spectrum antiobiotics?
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affect a wide range of bacteria.
adv= trmt of life threatening when no time to culture disadv= kills normal flora ex. amoxicillin, ampicillin |
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What are narrow spectrum antibiotics?
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limited use requires identification of bacteria, less disruption to normal flora ex. isoniasid
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What is 1/2 life and excretion of drug?
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longer 1/2 life of drug less frequency of doses to maintain effective level
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What is the blood-brain barrier?
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be able to reach cerebrospinal fluid
ex. treat menigitis or encephalitis |
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What is unstable in acid mean?
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can't be taken by mouth
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Why are drugs given in combination?
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antiobiotics given in a cocktail to treat disease, multiple types of antibiotics targeting different things
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What is an allergic adverse reaction?
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allergies= pcn causes rash, fever, anaphylactic shock
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What is a toxic adverse reaction?
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high concentrations;
streptomycin= kidney damage, deafness chloramphenicol= aplastic anemia |
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What is suppression of normal flora?
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antibiotic associated colitis (infection of colin), yeast infections
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What are targets of antibacterial drugs?
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inhibition of cell wall, protein synthesis, nucleic acid syn,metabolic pthways, cell membrane
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What are B-Lactam drugs?
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interferes with formation of peptide side chains by inhibiting PBP (PCN binding proteins )destroy cell wall
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What are examples of B-Lactam drugs?
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cephalosporins:
vancomycin- used rarely bacitracin- topically only PCN's |
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What drugs inhibit protein synthesis?
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aminoglycosides effective against mainly gram - but some gram +
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What are examples of protein synthesis inhibitors?
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streptomycin, neomycin (eye infections) tetracyclines (chlamydias and ricketssias) macrolides (walking pneumonia) Chloramphenicol
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What are inhibitors of nucleic acid synthesis?
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targets gyrase (supercoils DNA) or RNA polymerase
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What are examples of nucleic acid inhibitors?
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flouroquinolones= cipro (anthrax) (targets gyrase)
rifamycins=used in cocktail (targets RNA) |
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What are inhibitors of metabolic pathways?
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interfers with synthesis of compounds; ie. sulfa competes with PABA and prevents synthesis of folic acid
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What are inhibitors of cell membranes?
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alters membrane permeability causes leakage of contents. ie. polymyxin (toxic, topical only) (bacterial pink eye, skin infections)
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What are those that interfere with essential processes?
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interefers with cell wall synthesis; ie. isoniasid and etambul (inhibit formation of mycolic acid) rifomycin (RNA)
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What is selective advantage?
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population of bacteria treated with antibioitics, resistant ones survive and clone. selective pressure=antibiotic
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What are drug inactivating enzymes?
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penicillinase
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What is alteration in target molecule? (mechanism of resistance)
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drug cant bind to target, mutation in PBP causing PCN unable to attack
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What is decreasing uptake of drug? (mech. of resistance)
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bacteria alter permeability preventing entering of cell
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What is increased elimination of drug? (mech. of resistance)
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efflux pump excretes drugs out of cell. most dangerous b/c of resistance to most drugs
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What is innate resistance?
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intrinsic resistance (born with) ie. mycoplasma lacks cell wall= resistant to PCN
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What is acquired resistance?
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heavy use of antibiotics leading to multiple resistances
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What is spontaneous mutation?
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vertical evolution= passed onto daughter cells
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What is gene transfer?
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horizontal evolution, plasmids transfer resistance through conjugation
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What are examples of emerging resistance?
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entercocci=vancomycin resistant; s. aureus= methicillin resistant; mycobacterium tuberculosis= 1st line drug resistance
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How do we slow emergence and spread?
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physicians and health workers; patients; public education; global impacts
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