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47 Cards in this Set
- Front
- Back
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What are two ways to measure how good an antibiotic is for a given bacteria?
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1. Minimum inhibitory concentration (MIC)
2. Agar diffusion method |
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Where would you find the MIC?
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The first tbe where one see no growth.
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Antiseptics
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Generally too toxic for internal consumption but nontoxic enough to use topically
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alcohol, detergents, iodidem silver nitrate
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Antiseptics
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Disinfectants and sterilants
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Generally too toxic to be used even topically. Only used on inanimate objects. Used for sterilization of heat-sensitive materials.
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Alcohol, chlorines, formaldehyde, ethylene oxide, H2O2
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Disinfectants and Sterilants
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Chemotherapeutic Agent
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Any defined chemical used to treat disease caused by an invading organism
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How are chemotherapeutic agents classified/
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Based on their structure and or mode of action.
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What is strepomycin an example of?
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Carbohyrate containing
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What is Rifampin an example of?
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Macrocyclic lactones
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What is Mitomycin an example of?
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Quinone-like
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What is Ceftriaxone an example of?
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AA and peptide analogs
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What is polyoxin an exaple of?
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Heterocyclic compounds containing N.
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Cycloserine, Vanomycin, Bacitracin, Penicillins, Cephalosporins, Monobactams, Carbapenems do what?
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Block cell wall synthesis
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Actinomycin
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RNA elongation
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Quinolones, Novobiocin
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DNA Gyrase
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Trimethroprim, Sulfonamides
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Folic acid Metabolism
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Rifampin, stretovaricins
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DNA-directed RNA polymerase
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Erythromycin, Chloramphenicol, Clindamycin, Lincomycin
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Protein synthesis (translation)
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Polymyxins
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Cytoplasmic membrane structure
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Tetracyclines, spectinomycin, streptomycin, Gentamicin, tobramycin, Amikacin, Nitrofurans
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Protein synthesis (30S inhibitors)
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Mupirocin, Puromycin
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Protein Synthesis (tRNA)
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Selective toxicity
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Refers to the ability of an antimicrobial agent to be selectively more toxic to a microorganism than to animal cells
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Growth Factor analogs
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Mimic a factor required for growth. Type of synthetic Antimicrobial Drugs
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Sulfanilamide
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A p-aminobenzoic acid analog that blocks the synthesis for the vitamin folic acid (nucleic acid precursor) Type of sulfa drug
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What do Quinolones target?
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DNA Gyrase
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What is nalidixic acid an example of?
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Quinolones
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Ciproflaxin
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Fluronated derivative of nalidixic acid
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Why aren't most antibiotics useless in medicine?
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They are too toxic and have a low selective toxicity
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What type of bacteria are usu more sensitive to antibiotics?
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Gram positive
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Broad spectrum
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Antibiotics that act on both Gram positive and Gram negative
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What do medically important anitbiotics target?
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Cellualar structures or machinery of bacteria but not humans (ie cell wall, cytoplasmic mem, biosynthetic processes like transcription and translation)
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What type of antibiotic do we get from fungi?
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Beta-lactam antibiotics
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What percent of antibiotics are Beta-lactams?
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50%
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What are the two flavors of beta lactams?
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Penicillins and Cephalosporins
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What has a broader spectrum pen or cepha?
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cephalosporins
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What do beta lactams inhibit?
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Cell wall synthesis
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These attack the Beta subunit for RNA polymerase.
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Rifamycins, and streptovaricins
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This fits into the major groove of DNA and presents a road block for polymerase
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Actinomycin
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How would an antibiotic that was affecting the bacterial translational machinery work?
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They usu interact w/ rRNA and interfere w/ ribosome function
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Example of antibiotics that inhibit translation initiation.
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Kasugamycin
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Inhibit translational elongation
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Puromycin, chloramphenicol, erythromycin
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Aminoglycosides
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Amino sugars linked by glycosidic bonds. They all inhibit protein sysnthesis by interacting w/ 30S subunits.
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What type of bacteria are aminoglycosides effective against?
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G- but they have been replaced by less toxic, more effective semi-synthetic antibiotics.
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Macrolides
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Lactone rings connected to sugars. Generally inhibit the 50S ribisomal subunit. Erythromycin is commonly used by people who are allergic to penicillin.
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Tetracyclines
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4-ring structure. One of the first broad specturm antibiotics
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What do tetracyclines inhibit?
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Protein synthesis that block the 30S subunit A site.
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