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100 Cards in this Set
- Front
- Back
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What is selective toxicity?
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the ability of a drug to injure a target cell/organism w/o injuring other cells/organisms that are in intimate contact with the target
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What are some ways an antibiotic is toxic to microbes but harmless to the host?
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Disruption of the bacterial cell wall: Inhibition of an enzyme unique to bacteria: disruption of bacterial protein synthesis
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Why do some drugs disrupt the bacterial cell wall?
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Because human cells have no cell wall, drugs directed at this structure do not affect us.
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Why do some drugs inhibit enzymes unique to bacteria?
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Because they inhibit enzymes that are critical to bacterial survival but not to our survival.
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Why do some drugs disrupt bacterial protein synthesis?
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Bacterial and mammalian ribosomes are not identical so we can make drugs that disrupt function of one but on the other
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What is an example of drugs that disrupt bacterial cell walls?
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Penicillins, cephalosporins, weaken the cell wall and thereby promote bacterial lysis
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What is an example of a drug that inhibits an enzyme needed for bacterial to make folic acid?
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sulfonamides block the conversion of PABA, a precursor of folic acid. Since mammal cells do not make their own folic acid, sulfonamide toxicity is limited to microbes.
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What is the definition of "narrow spectrum antibiotics"? and when would they be used?
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They are against a a few specific microbes
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What is the definition of Broad Spectrum Antibiotics?
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They are active against a wide variety of microbes
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What is generally preferred, Broad spectrum or narrow spectrum antibiotics?
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Narrow spectrum
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What is a bactericidal drug?
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A drug that is lethal to bacterial at clinically achievable concentrations.
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What is bacteriostatic drugs?
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they slow bacterial growth but do not cause cell death. Used when elimination of bacteria must be ultimately be accomplished by the host defenses-immune system working
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How long can MSRA live out side the body?
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About a year
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Why are antibiotics overused?
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Because people are quick fix
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What %% of staph is methel resistant?
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65% and increasing
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How are bacteria classified?
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By their shape, color, type of air, genes.
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How do bacteria live?
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sugars nitrogen, sulfur, phosphorus, proper pH, proper temp, proper o2 concentration
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Why do we not just give a broad spectrum drug to everyone?
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Because it would increase resistance
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Do we culture everyone who has an infection?
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no because of cost. We use averages like 80% of UTI's are e-coli...use a gram negative bacteria-selective for that organism
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How do we chose which drug?
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By what kind of infection they have. E coli is a gram negative.
Staph and Strep are gram positive |
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Know the __________is paramount for selecting a antibiotic?
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organism..... Match the drug with the bug.
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Which micro is harder to get rid of?
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Gram negative. Gram positive only have a cell wall. Negative have a extra membrane which is why positive is easier to treat
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The first antibiotic treated what kind of bacteria?
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Gram positive
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How can you tell the difference between gram positive and gram negative bacteria for initial identification?
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By staining. Gram positive turn purple, gram negative turn red
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What are microbes that need oxygen and can grow in the air?
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aerobes
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What are bacteria called that can't grow if oxygen is present
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anaerobes
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What are bacteria called that can brow with or without oxygen?
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facultative organisms
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How do we protect ourselves? (physical barriers from bacteria)
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skin, membranes, cilia, mucus, flushing effect-tears, secretions, cough reflect (lung protection), urine flow, low pH (acid on skin, stomach), immune system.
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How many cigarettes a day will cause cilia to be paralyzed?
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1 cigarette
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What makes you think there is an infection?
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fever, pain, inflammation, xray evidence, increased WBC
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What is selective toxicity?
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the ability of a drug to injure a target cell or TARGET the organism without injuring other cells
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What is purulent?
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Puss--puss drainage
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Do you need to be on an antibiotic every time you have an infection?
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No, then everyone would be running to the doctor every time acne broke out
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How can a drug be highly toxic to the micro but not injure us?
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because of the cell walls on microbes.
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How do Sulfonamides work against antibiotics?
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Sulfonamides block an enzyme necessary to make folic acid. PAB is a precursor to folic acid
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What drugs inhibit cell wall synthesis?
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Penicillins, cephalosporins, imipenem, vancomycin
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What drugs disrupt the cell membrane?
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amphotericin B, daptomycin, ketonazole
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What drugs are bactericidal inhibitors of protein synthesis?
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aminoglycosides
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What drugs are bacteriostatic inhibitors of protein synthesis
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clindamycin, erythromycin, linezolid, tetracylines
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What drugs interfere with synthesis or integrity of bacterial DNA?
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fluoroquinolones, methonidazole, ripfampin
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Why do antimicrobial drugs not work on colds?
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Because they do not work on virus'
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When should broad-spectrum antibiotics be used?
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When there is a serious threat to life. Only until the culture is identified. then switch over to a narrow spectrum drug that is appropriate for the microbe
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What is a culture & sensitivity test?
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A lab test that will show what antibiotic will work for that particular infection
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Why do we have a resistance problem with antibiotics?
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People don't finish the medications because they feel better. Microbes change themselves, microbes exchange resistance strains between themselves, over prescription
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Why is it bad to just chose an antibiotic that is too much for the particular infection.
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Because it promotes microbial drug resistance
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How should an antibiotic be chosen?
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by the particular infection/organism
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What is over-prescription?
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Giving a drug that will work but is too big that can promote microbial drug resistance
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What are some ways we promote drug resistance?
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By stopping medication early, by sharing medication, by using out-of-date drugs from friends, by using antibiotics when not needed.
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What is the best way to stop drug resistant microbes?
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Education, use ONLY when necessary
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What should be done first, the blood culture or administer the antibiotic?
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the blood culture
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What is a common side-effect of antibiotic therapy?
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a secondary infection (from another infection) because normal flora may have been destroyed.
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Why is normal flora good?
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Normal flora keeps the overgrowth of pathogens down. They protect us.
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What is the CDC's effort to prevent antimicrobial resistance (what do they recommend)?
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The recommend 1)vaccinate, 2) get catheters out, 3) choose the right antibiotic, 4) Access the experts-consult and infectious disease expert to improve patient outcome, 5) practice antimicrobe control, 6) use local data, 7) treat infection not contamination.8) treat the infection not colonization 9) know when to day no to vanco 10) stop treatment when cured/culture is negative
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How long should an IV be in place?
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no more then 3 days.
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What is vancomyicin used?
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only for MRSA (great for gram-negative)
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How can nurses decrease the incidence for nosocomial infections?
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WASH HANDS, remove invasive devices as soon as possible, encourage patients to get vaccinations
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What drug is the first mass-produced antibiotic?
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Penicillin, first against gram positive.
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What is penicillin's structure?
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they have a beta-lactam ring. (Beta-lactam antibiotics)
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What is the safest antibiotic?
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penicillins
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How do penicillins kill bacteria?
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by disrupting their cell wall
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What is the most common adverse effect of penicillins?
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allergies
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How should penicillins be given?
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Most penicillins should be given on an empty stomach--this enhances absorption. 1 hour before or 2 hours after a meal
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Beta-lactam ring is What???
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the anitbiotic itself
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If you are allergic to penicillin will you be allergic to all beta-lactam ring antibiotics?
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yes
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What do all of the penicillin drugs end in?
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"cillin". Example...methicillin, nafcillin, cictoxacillin, ampicillin, aamoxicillin, piperacillin.
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What types of penicillins are there?
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narrow spectrum, narrows spectrum penicillinase resistance, broad spectrum, extended-spectrum
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Who makes beta-lactamase and what is it targeting
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microbes make beta-lactamase to target the beta-lactam ring
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When is a beta-lactamase inhibitor used?
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In combination with penicillins
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What does beta-lactamase inhibitors do?
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they are drugs that inhibit bacterial beta-lactamases. By combining a beta-lactamase inhibitor with a penicillnase sensitive penicillin, it can extend the antimicrobial spectrum
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What are some penicillins that have a beta-lactamase inhibitor with it?
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Zosyn, Timentin, Augmentin.
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What is the major side effects/reactions from penicillins?
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anaphylaxis-allergic reaction.
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What should you do if a pt is having an anaphylaxis reaction to penicillin?
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stop the drug, give epinephrine, and/or aminophylline, vasopressors, corticosterois, hydration, benadryl
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What are the s/s of anaphylaxis reaction to penicillin?
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hives, tachycardia, SOB, wheeze, rashes...immediately get to ER
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What is angioedema?
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An allergic reaction
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What do we need to know about penicillins?
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1) Beta-lactam ring
2) safest 3) biggest side effect-allergy 4) Gram positive |
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What kind of drug is added to penicillin to add to its effectiveness?
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Beta-lactamase inhibitors
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What is the great thing about cephalosporins?
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They work against gram negative bacteria
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What does cephalosporins contain?
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a beta-lactam ring
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If cephalosporins contain a beta-lactam ring and the pt is allergic to penicillin, what is the logical conclusion?
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That the pt may be allergic to cephalosporins. use caution
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How do cephalosporins work against bacteria?
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they are bacteriocidal drugs and act by attaching to penicillin-binding protein to inhibit cell wall synthesis.
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How many generations of drugs are there with cephalosporins?
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There are 4 generations. The each generate better results
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What are the ways in which a cephalosporin gets better in each new generation of drug?
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1) increasing activity against Gram negative bacteria.
2) Increasing resistance to beta-lactamases 3) Increasing ability to reach the CSF |
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What are the adverse effects of Cephalosporin?
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Hypersensitivity, Have to be taken with food, rashs, bleeding.
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If you you have a gram positive infection, should you take a 1st or 4th generation cephalosporin?
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the 1st generation are better for gram positive, the 4th generation are better with gram negative
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Why would there be a cross reactivity with cephalosporins and penicillins?
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Because they are similar in structure (beta-lactam ring)
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What is the difference between 1st generation and 4th generation cephalosporins?
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4th generation agents have more activity against gram negative organisms
4th generation agents are more able to reach CSF 1st generation agents ore more vulnerable to destruction by beta-lactamases |
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What is broadest spectrum antibiotic we know of
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Carbapenems
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What is the structure of a carbapenem?
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The have a beta-lactam ring, and are very broad spectrum
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What are the only three carbapenum drugs?
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Imipenem/cilastatin (PRIMAXIN)
meropenem (MERREM) ertapenem (INVANZ) |
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If the pt has seizure disorders what carpapenum would you NOT want to give
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Primaxin
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What drug is used in combination with carbapenems to inhibit the human enzyme 'dehydropeptidase that degrades impipenem drugs
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Cilastatin
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Why is cilastatin combined with imipenem?
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To increase the urinary concentration of the drug by inhibiting the enzyme in the kidney that breaks down the drug
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What are the adverse effects of carbapenems?
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Primarily GI problems, hypersensitivity, high cross-sensitivity with other bets-lactam antibiotics
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What is the newest class of beta-lactam antibiotics?
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Monobactams
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What kind of infections are monobactams best used against?
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gram negative bacteria (narrow spectrum)
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What is an example of a monobactam?
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Azactam
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Will a pt that has penicillin allergies have a reaction against monbactams?
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Probably not because the leta-lactam ring is fused a little differently.
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Azactam is what kind of drug?
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Its a monobactam. Its an anit-infectives. Its used to treat serius gram negative infections that include septicemia, UTI. SERIOUS infections
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Is azactam good to treat against staph or strep?
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NO, because azactam is only good against gram negative bacteria.
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What are the 4 beta-lactam ring drugs classifications?
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penecillins
Carbapenems Cephalossporins Monobactams |
