Week 7 Mastering Chapter 10 questions – Flashcards
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Why is penicillin regarded as the first true antibiotic?
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It is produced naturally by the fungus Penicillium.
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What is microbial antagonism?
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the ability of the normal flora to outcompete and outgrow pathogens
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What is a superinfection?
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Superinfection is a disease caused by an organism that is often an opportunist or one that was present in low numbers. Superinfection is a sequel to removal of the normal flora by antibiotic treatment.
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What causes thrush?
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Candida albicans
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Which of the following classifications would best describe Candida albicans?
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yeast
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If the patient were to get a subsequent urinary tract infection, what should the doctor prescribe knowing that she is susceptible to thrush?
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The doctor should prescribe an antibiotic specific for the bacterial species causing the urinary infection.
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oral administration method graph
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start at bottom, goes a little higher in the middle, and goes back down
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intramuscular administration graph
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start at bottom, spikes high middle, then goes back down
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continuous intravenous administration graph
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starts at bottom, spikes very quickly, and stays there for the duration of the graph
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What is meant by selective toxicity?
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Chemotherapeutic agents should act against the pathogen and not the host.
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Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?
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Humans and other animal hosts lack peptidoglycan cell walls.
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Why is polymyxin only used on the skin?
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It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead.
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Quinolones and fluoroquinolones act against what bacterial target?
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DNA gyrase
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Why is it difficult to find good chemotherapeutic agents against viruses?
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Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.
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__________ cells would be expected to be the most susceptible to the action of polyene drugs such as amphotericin B, while __________ cells would be the least susceptible.
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Fungal; bacterial
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Why is the drug actinomycin used only in research applications or in the treatment of cancer?
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because it is active against both prokaryotic and eukaryotic cells
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Which of the following is NOT a direct mode of action of antimicrobial drugs?
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inhibition of flagella formation
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An antimicrobial drug that blocks the transport of NAG and NAM from the cytoplasm is targeting which of the following cellular processes?
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cell wall synthesis
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Why do antimicrobial agents active against mycobacteria have to be administered for months or years rather than the typical 10-30 days prescribed to treat other infections?
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Mycobacteria reproduce very slowly.
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Which of the following antimicrobial drugs would likely be useful to treat a staphylococcal infection?
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erythromycin
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Which of the following is NOT a type of side effect exhibited by antimicrobial drugs?
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inhibition of host cellular enzymes
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An antimicrobial disk on a Kirby-Bauer plate that shows no zone of inhibition indicates that the microbe being tested is __________ to the drug.
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resistant
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Put the following routes of administration in order, from the route that results in the highest concentration of drug in the bloodstream to the route that results in the lowest concentration: a. topical b. intravenous c. oral d. intramuscular
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b d c a
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What is DOT?
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Directly Observed Therapy
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Which drug for the treatment of tuberculosis inhibits RNA production and colors body secretions red-orange?
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rifampin
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What is the therapeutic index?
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the drug dose the patient can tolerate divided by the effective dose
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How did the multi-drug-resistant strains of Mycobacterium tuberculosis, like those in the prison, arise?
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conjugation and exchange of resistance factors located on plasmids
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Which antibiotic is overcome by beta-lactamases?
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Penicillin
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How might efflux pumps increase antibiotic resistance in bacteria?
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Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.
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Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what?
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PABA
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Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?
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Penicillin disrupts the cell wall, which is located outside of the cell membrane.
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Membrane transport proteins are required for which mode(s) of antibiotic resistance?
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Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.
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What is meant when a bacterium is said to become "resistant" to an antibiotic?
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The bacterium is neither killed nor inhibited by the antibiotic.
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When a patient is treated with antibiotics, __________.
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the drug will kill or inhibit the growth of all of the sensitive bacterial cells
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The process of acquiring antibiotic resistance by means of bacteriophage activity is called
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transduction
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Which of the following mutations would not result in antibiotic resistance?
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Silent mutation
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R-plasmids are most likely acquired via
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bacterial conjugation.
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Which of the following activities can be shown to increase resistance among microbial populations?
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taking antibacterial drugs for viral infections
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If a particular bacterial species is resistant to beta-lactam antibiotics, which of the following might you expect to find inside the bacterial cells?
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R plasmids
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Which of the following is NOT associated with microbial mechanisms of resistance? a. Denaturation of proteins b. porins .c MfpA protein d. beta-lactamases
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a
