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125 Cards in this Set
- Front
- Back
chemotherapeutic agents
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A chemical that has been sythesized by chemists in a lab or produced by a modification of a preexisting chemical that kills microorganisms.
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antibiotics
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a product of the metabolism of a microorganism
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What is the objective of a selectively toxic drug?
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to kill or inhibit a pathogen while damaging the host as little as possible
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What three things does the degree of selective toxicity depend on?
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- therapeutic dose
- toxic dose - therapeutic index |
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Therapeutic dose
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drug level required for clinical treatment of a particular infection
need enough of the drug to kill a pathogen so it can't establish disease |
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toxic dose
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drug level when undesirable effects are produced
-make extremely sick |
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Therapeutic index
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toxic dose/ therapeutic dose
higher therapeutic index, better chemotherapeutic agent |
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higher therapeutic index, _____ chemotherapeutic agent
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better
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____ drugs are narrow-spectrum, while ___ are broad-spectrum
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most- narrow-spectrum
some- broad-spectrum |
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Most drugs are narrow-spectrum. They treat ____
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only one type of microbe
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ISONIAZID is good for tuberculosis. It won't work for something else like a sinus infection. Is it narrow or broad spectrum?
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narrow
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_____ is a narrow spectrum drug that is good for tuberculosis.
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Isoniazid
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Some drugs are broad-spectrum. Name three different broad-spectrum drugs.
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Neomycin
Zeocin Sulfonamides |
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Nemomycin is effective against what bacteria?
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gram + and -
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Zeocin is a broad-spectrum drug that is _____ AND ____
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anti-bacterial and anti-fungal
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Sulfonamides is a broad-spectrum drug that is _____, _____, and _____
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anti-bacterial
anti-fungal anti-protozoal |
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Bactericidal
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kills target pathogen
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Bacteriostatic
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reversibly inhibits growth of pathogen
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What is the difference between bactericidal and bacteriostatic?
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bactericidal kills. bacteriostatic inhibits.
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Antibiotics can be of what three types?
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Natural
Synthetic Semi-synthetic |
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Natural antibiotics are _____
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produced by some living organism
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Streptomyces is a living organism that makes what three natural antibiotics?
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Streptomycin
chlortetracycline erythromycin |
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Streptomycin, chlortetracycline, and erythromycin are natural antibiotics made by what living organism?
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streptomyces
*Streptomyces is a bacterium |
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What living organism makes the natural antibiotic, penicillin?
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penicillium
*penicillium is a fungus *penicillin inhibits bacterial growth |
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Synthetic antibiotics are what?
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manufactured from non-natural products. They are chemotherapeutic agents.
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Give two examples of synthetic antibiotics.
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sulfonamides
trimethoprim |
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Semi-synthetic antibiotics are what?
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chemical modification of natural antibiotics
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Give an example of semi-synthetic antibiotics
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penicillin derivatives: ampicillin, carbenicillin, methicillin
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Name three penicillin derivatives
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ampicillin
carbenicillin methicillin * a lot of ppl are allergic to penicillin, so make penicillin derivatives in the lab |
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What are the 5 mechanisms of antimicrobial action?
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- protein synthesis
- nucleic acid - cell wall - cell membrane - metabolic reactions |
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There are 5 things you can target (protein synthesis, nucleic acid, cell wall, cell membrane, metabolic reactions), that kills microbes, but not ____
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but not necessarily the host
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What does polymyxin B disrupt?
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Cell membrane
*cell membrane is the site of where to attack a microbacterium |
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Is polymyxin B natural, synthetic, or semi-synthetic?
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natural
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Polymyxin B is a natural antibiotic that comes from ____
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Bacillus
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What is polymyxin B effective against?
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Gram - bacteria (P. aeruginosa)
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Polymyxin B is effective against Gram- bacteria. Give an example
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P. aeruginosa
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What does polymyxin B do?
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Binds cell membrane components, alters membrane permeability (causing cell leakage, death)
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Polymyxin B can be found in ______ and _____
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bacitracin (Gram +) and neomycin (broad spectrum)
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Polymyxin B is only for topical use. If it is ingested, Polymyxin B can cause what?
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numbness in the extremities, kidney damage, respiratory arrest
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Sulfonamides are natural, synthetic, or semi-synthetic?
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synthetic
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Give one type of sulfonamide
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Sulfanilimide
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Sulfanilimide is a structural analog of ____
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p-aminobenzoic acid (aka PABA)
(-SO2NH2 vs. COOH) |
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Sulfonamides inhibits _____ production by competing with p-aminobenzoic acid for active site of dihydropterate synthase, an enzyme
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folic acid
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Sulfonamides inhibits folic acid production by competing with _____ for active site of dihydropterate synthase, an enzyme
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p-aminobenzoic acid
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Sulfonamides inhibits folic acid production by competing with --aminobenzoic acid for active site of _____, an enzyme
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dihydropterate synthase
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Folic acid is required for ____
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nucleic acid production
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bacteria make their own ____, but not humans
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folic acid
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Sulfonamides have a high ____, but about 5% of ppl are allergic
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therapeutic index
*toxic dose/ therapeutic dose higher therapeutic index, better chemotherapeutic agent |
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Give two examples of sulfonamides
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sulfamethoxazole
sulfisoxazole |
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What two antibiotics inhibits DNA Synthesis?
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Quinolones
Fluoroquinolones |
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Give an example of QUINOLONES, which disrupts prokaryotic DNA gyrase (inhibits DNA Synthesis)
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Nalidixic acid
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Nalidixic acid selectively inhibits _____, an enzyme required for DNA replication
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DNA gyrase
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What is Nalidixic acid effective against?
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only effective against certain types of urinary infections.
*most likely narrow-spectrum |
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Who is Nalidixic acid bad for? whY?
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Bad for kids & pregnant women because it affects development of cartilage
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Give two types of fluoroquinolones, which inhibits DNA Synthesis
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Ciprofloxacin
norfloxacin |
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Fluoroquinolones were developed as improvements over nalidixic acid (an extra F added), because they ____ and ____
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penetrate tissue better
more broad-spectrum (can treat urinary infections + anthrax + others) |
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What is a drug that inhibits RNA synthesis?
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Rifampin
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Is Rifampin natural, synthetic, or semi-synthetic?
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semi-synthetic
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Rifampin inhibits DNA-dependent ______ in bacteria
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RNA polymerase, an enzyme
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What three things is Rifampin used for?
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Tuberculosis
Leprosy Protection against bacterial meningitis |
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Rifampin turns bodily secretions ____
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reddish orange
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what four things inhibits cell wall synthesis?
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Penicillins
Bacitracin Cephalosporins isoniazid |
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What do all penicillins have?
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beta-lactam nucleus
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Penicillins inhibit transpeptidation (linking of polymers w/ amino acid chains) and consequently _____
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cell wall synthesis (results in osmotic lysis)
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Penicillins inhibit _______(linking of polymers w/ amino acid chains) and consequently cell wall synthesis (results in osmotic lysis)
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transpeptidation
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What is a semi-synthetic derivate of Penicillin?
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ampicillin
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What is good about ampicillin compared to penicillin?
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more acid stable
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What are two problems with penicillins?
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allergic reactions
growing resistance |
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If you are allergic to penicillin, then you could take _____
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Cephalosporins
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What does Cephalosporins inhibit?
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cell wall synthesis
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Give two examples of cephalosporins
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cephalexin (Keflex)
cephalothin (Keflin) |
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Are cephalosporins natural, synthetic, or semi-synthetic?
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Natural, from fungus Cephalosporium
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Cephalosporins are a natural antibiotic from the fungus _____
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Cephalosporium
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Cephalosporins are similar to penicillin in waht way?
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beta-lactam ring
similar mechanism of action |
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Cephalosporins have a beta-lactam ring like penicillin, therefore cephalosporins have a similar _____
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mechanism of action
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Cephalosporins are a useful alternative to penicillin in case of ___ or ___
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allergy or resistance
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Bacitracin, another cell wall synthesis inhibitor, interferes with ____, a carrier that transports peptidoglycan subunits to the cell wall
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bactoprenol
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Give four antibiotics that inhibit Protein Synthesis.
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Tetracyclines
Aminoglycosides Macrolides Chloramphenicol |
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Tetracyclines are narrow or braod-spectrum?
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broad-spectrum (affects Gram - and +)
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What makes up tetracyclines?
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four benzene rings
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Some tetracyclines are natural and are produced from ___
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Streptomyces
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Some tetracyclines are natural and produced from Streptomyces. Give two examples.
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Chlortetracycline
Oxytetracycline |
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Some tetracyclines are semi-synthetic. Give four examples.
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Tetracyline
Doxycycline Methacycline Minocycline |
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Tetracyclines all inhbibit protein synthesis by binding _______
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30S ribosomal unit
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All inhibit protein synthesis by binding 30S ribosomal unit- inhibits binding of _____ to ____
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tRNA to ribosome
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Who are tetracyclines bad for? why?
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Bad for kids and pregnant women- problems with bone formation (yellow teeth)
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Tetracyclines is the drug of choice for _____ and _____ diseases
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rickettsial and chlamydial diseases
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Aminoglycosides inhibits protien synthesis. They are amino groups bound to ____
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glycosides (carbohydrates)
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What are glycosides?
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carbohydrates
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What three aminoglycosides comes from Streptomyces?
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Streptomycin
Kanamycin Neomycin |
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What aminoglycoside comes from Micromonospora purpurea?
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Gentamicin
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Aminoglycosides prevent reading of ____ by irreversibly binding to ribosome
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mRNA
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Aminoglycosides prevent reading of mRNA by _____
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irreversibly binding to ribosome
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Why are aminoglycosides toxic?
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Deafness, renal damage, loss of balance
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What are macrolides composed of?
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12-22 carbon lactone ring
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Are macrolides broad-spectrum or narrow?
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broad-spectrum
(Gram +/-, mycoplasma) |
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Give four examples of macrolides
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erythromycin
clindamycin azithromycin zithromax |
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Macrolides inhibit ____
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peptide chain elongation
(protein synthesis) |
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Legionnaire's Disease is transmitted by?
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air
air conditioners humidifiers the spray of jacuzzi tubs |
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What are Macrolides used to treat?
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Legionnaire's Disease
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Chloramphenicol binds ____ and blocks ______ to inhibit protein synthesis
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ribosome
peptide bond formation |
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Is Chloramphenicol natural, synthetic, or semi-synthetic?
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natural, from Streptomyces
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Where is Chloramphenicol produced from?
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Streptomyces
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Is Chloramphenicol narrow or broad-spectrum?
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broad-spectrum (bacteria, small bacteria, fungi)
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Chloramphenicol has a low ____: used only in life-threatening situations
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therapeutic index
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Chloramphenicol can cause _____ by preventing hemoglobin from being incorporated into RBC (red blood cell)
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aplastic anemia
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Besides aplastic anemia, what else can chloramphenicol cause?
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gray syndrome
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Gray syndrome is a toxic reaction to chloramphenicol. It is the breakdown of the ___
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cardiovascular system
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What are the two bad side effects of chloramphenicol?
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Aplastic anemia
Gray syndrome |
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What are the 6 things that affect bacteria?
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cell wall
cell membrane metabolism (folic acid) DNA synthesis RNA synthesis protein synthesis |
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What are the four mechanisms of resistance?
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Modification of target
Prevent entrance of drug prump drug out of cell chemical modification |
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Modification of target. Resistance to ______ develops when bacteria alter structure of enzymes used to synthesize folic acid
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sulfonamides
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Resistance to _____ develops when bacteria alter structure of ribosomes
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streptomycin
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Prevent entrance of drug. Mycobacterium has _____ in cell wall
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mycolic acid
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Mycobacterium has mycolic acid in cell wall. Mycolic acid is _____ to most drugs
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impermeable
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Pump drug out of cell. Enzymes such as plasma membrane _____ pumps drugs out of cell.
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translocase
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Pump drug out of cell. Some microbes have ___
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multi-drug resistance pumps
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Inactivation through Chemical Modification. Penicillinase (beta-lactamase) can effect ______- inactivating antibiotic
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hydrolysis of beta-lactam ring
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_________ (beta-lactamse) can effect hydrolysis of beta-lactam ring- inactivating antibiotic
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Penicillinase
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Inactivation through Chemical Modification. Penicillinase (Beta-lactamase) can effect hydrolysis of beta-lactam ring- inactiving antibiotic. This type of resistance can be encoded by ____
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plasmids.
transferred by conjugation and transformation |
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Give two reasons as to why microbial drug resistance is increasing
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indiscriminate use of chemotherapeutics
transmission of R factors among microbes |
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R factors transferred between _____ through conjugation
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unrelated strains
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What is indiscriminate use? (3 pts)
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Prescription of antibiotics for viral infections
Low-level use of antibiotics for prevention of infection inclusion of antibiotics in animal feed |
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By the process of natural selection, microorganisms that are resistant to a particular drug gradually become ____
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predominant in a population
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What does PPNG stand for?
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penicillinase-producing Neisseria gonorrhoeae
*No PPNG strains before 1976 |