Microbiology Final- Chapter 20 (Viruses) – Micro Final – Cha – Flashcards
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| Chemotherapy: |
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| using chemical substances to treat diseases. |
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| What two ways can chemical substances be made? |
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| 1.made in the lab 2.maid by microbes |
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| what type of drugs are made in the lab and what is an example of one? |
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| -SYNTHETIC DRUGS ex) Sulfanilamide (sulf drug) |
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| what type of drug is made by microbes? |
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| -ANTIBIOTICS ex)Penicillin (Fleming 1928) |
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| what is the main source of antibiotics? |
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| BACTERIA! |
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| what is it called when an antibiotic is modified in a lab? |
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| semi-synthestic |
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| what is it called when an antibiotic is modified in a lab? |
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| semi-synthestic |
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| antimicrobic: |
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| microbe-made or man-made agent |
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| Selective toxicity: |
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| Drug is (selectively) more toxic to microbe than to host |
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| Narrow Spectrum Drug: |
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| Narrow range; natural penicillin (penicillin G) affects only gram POSITIVE bacteria. |
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| Broad spectrum drug: |
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| wide range; semi-synthetic penicillin (ex: Ampicillin); affects gram positive and gram negative bacteria. |
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| suffix-end-cidal or static=? |
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| cidal means to kill and static means to stop growth. |
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| Antimicrobial Drugs: Drugs that inhibit cell wall synthesis- |
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| Are bactericidal- ex) Penicillin's, bacitracin, vanomycin and others. *exceptions: isoniazid, and ethambutol (which blocks mycolic acid insertion in cell wall of Mycobacterium tuberculosis) are bacteriostatic |
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| Antimicrobial Drugs: Drugs that inhibit protein synthesis- what size ribosomes does mitochondria have? |
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| Eukaryotic mitochondria has 70S ribosomes |
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| Antimicrobial Drugs: Drugs that inhibit protein synthesis |
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| -are bacteristatic examples) tetracycline's (broad spectrum), chloramphenicol (very broad spectrum, erythromycin |
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| Antimicrobial Drugs: What is the exception to the bacteriostatic drugs? |
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| strptomycin group (the aminoflycosides) are bactericidal |
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| Antimicrobial Drugs: Drugs that damage plasma membrane |
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| are bactericidal ex) polymyxin B- makes cell permeable=increase water uptake=cell lysis! |
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| Antimicrobial Drugs: Drugs that inhibit nucleic acid synthesis: |
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| -are bactericidal ex) Rifampin- inhibits RNA synthesis and cyprofloxacin inhibits DNA synthesis. |
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| Antimicrobial Drugs: Drugs that inhibit synthesis of essential metabolites. ex) Sulfa drugs |
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| are bacteriostatic-inhibits growth ex) TMP(Trimethoprim-mainly used in the prophylaxis and treatment of urinary tract infections), SMZ (used to treat UTIs and strep most commonly), sulfanilamide |
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| Antifungal Drugs: Antibiotics- Griseofulvin: |
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| fungistatic, interfers with mitosis (for ringworm infection) |
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| Antifungal Drugs: Antibiotics-Amphotericin B:(a polyene compound) |
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| fungicidal, binds sterols in plasma membrane (for systemic infections-toxic side effects) |
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| Antifungal Drugs: Synthetics- Clotrimazole: (an azole compound) |
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| -fungicidal, blocks synthesis of plasma membrane sterols -for jock itch, and ringworm |
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| Antifungal Drugs: Synthetics: Flucytosine |
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| -fungicidal -inhibits RNA synthesis and therefore protein synthesis -systemic use -toxic side effect |
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| Antifungal Drugs: Synthetics: Tolnaftate |
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| -fungicidal (for treating athletes foot) |
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| Antiviral Drugs: General non-nucleoside agents: Interferon (IFN) |
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| ex) alpha IFN -inhibits virus spread (for viral hepatitis) |
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| Antiviral Drugs: General non-nucleoside agents: Amantadine and Rimantadine: |
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| -These block uncoating of influenza -Rimantadine-less toxic -A third drug-Oseltamivir (Tamiflu) -inhibits neuaminidase (N spike on influenza cell) of flu virus |
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| Antiviral drugs: Nucleoside analogs: |
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| -most antivirals are in this group -are purine (A or G) or pyrimidine (T, C or U) analogs -interfere with DNA or RNA synthesis |
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| Antiviral Drugs: Purine Analogs: Vidarabine, Acyclovir, Ganciclovir |
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| -for herpesviral infections (acyclovir-> genital herpes-no cure) |
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| Antiviral Drugs: Purine Analogs: Ribavirin |
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| for viral pneumonia (aerosol spray) |
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| Antiviral Drugs: Pyrimidine Analogs: |
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| A- AZT (zidovudine) B- DDL C- ddC -a, b, c all interfere with dviral reverse transcriptase -all for HIV treatment |
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| Antiviral Drugs: Enzyme inhibitors: (anti-HIV) |
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| -inhibits viral protease (for HIV treatment) -ex) Indinavir, and Saquinavir |
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| Antiprotozoan Drugs: Chloroquine: |
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| -inhibits DNA synthesis (for Malaria disease) |
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| Antiprozoan Drugs: metronidazole: |
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| -Causes DNA damage -Broad spectrum against: -Trichomonas vaginitis -Entamedba diarrhea -Anaerobic bacteria |
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| Anthelmintic Drugs (Worms) Helminth= |
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| worm (flat or round) -tapeworm and flukes are flatworms |
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| Anthelmintic Drugs: (Worms) Niclosamide |
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| -prevents ATP generation for tapeworms |
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| Anthelmintic Drugs: (Worms) Praziquantel: |
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| -Disrupts plasma membrane permeability -for tapeworm and flukes |
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| Anthelmintic Drugs: (Worms) Mebendazole: |
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| -disrupts nutrient absorption -for intestinal roundworms |
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| Drug Resistance: Drug Resistance= |
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| microbial resistance to a drug (not host resistance)D |
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| Drug Resistance: Heredity drug resistance |
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| -passed from one bacterium to another -via plasmids called Resistance factors (R-factors |
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| Drug Resistance: Mechanisms involved: |
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| a) drug can't penetrate microbe to reach target site b) target site is altered by mutation c)microbial enzyme ex-Penicillinase (or beta lactamase) breaks down drug |
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| Drug Resistance: To minimize drug resistance: |
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| 1-use drug only when absolutely needed 2-follow doctor's orders (dosage, freq) 3-use combination therapy |
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| Drug Resistance: Why is it good to use combination therapy? |
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| a) for synergistic effect-ex) Penicillin-streptomycin (penicillin-tetracycline-> antagonistic-do not mix penicillin and tetracycline) b) to decrease toxicity of individual drug c)to decrease emergence of resistant strains |
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| Tests to guide chemotherapy: 1. Disk Diffusion Method---agar diffusion: |
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| -kirby-Bauer method tests microbial susceptibility to drugs -the E test can determine "MIC"-defined below -Agar solid |
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| Tests to guide chemotherapy: 2.Broth Dilution Test: |
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| -Agar liquid -uses serial dilutions of a drug to determine a) MIC=minimal inhibitory concentration that INHIBITS growth of microbes b)MBC=minimal bactericidal concentration, lowest concentration that KILLS the microbes |
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| New/future drugs: -new drugs (Under development): |
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| Target: drug-resistant microbes Sources: plandts, animals (ex Antimicrobial peptides from frog skin), and synthetic compounds -synthetic compounds=example: -synthesize DNA--called Triplex agent and antisense agent -these neutralize the genes and mRNA's that code for microbial pathogenic proteins |
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| How fly is Stuart? |
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| Super fly! |
