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153 Cards in this Set
- Front
- Back
What antibacterial were discovered in 1910?
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-salvarsan, an arsenic derivative effective against syphilis
-by Erlich |
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What antimicrobial drugs were discovered in the 1930's
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-sulfoamides by Domagk
|
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What antimicrobial was discovered in 1928?
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-first antibiotic discovered by Fleming
|
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What was discovered in 1940?
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1st clinical trials of penicillin by Florey, Chain
|
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How can selective toxicities be realized?
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-attacking targets unique to the pathogen cell that are not present in the host
-attacking targets in the pathogen cell that are similar but not identical to those in the host -attacking targets in the pathogen cell that are shared by the host, but that vary in importance between pathogen and host |
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Who found the 1st microbe?
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-Hook-dutch scientist, made first microscope
|
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What is selective toxicity?
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-microbes are inhibited selectivity without damage to the host cell
-ideally no patient harm and lethal to antimicroorganism |
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What are bactericidal effects of the antibiotics?
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-will kill microorganisms without help from host's immune system
|
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What are bacterialstatic effects of the antibiotics?
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-inhibit bacterial cellular replication but will not kill
-must have healthy immune system to kill microbe |
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What are antibiotics?
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-chemicals produced by microorganisms
-have capacity to kill or inhibit the growth of microrganisms |
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What are 3 factors that prevent infection?
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-environmental factors
-vaccination -education |
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What are antimicrobial drugs classification based on?
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-mechanism of action
-chemical structure -specturm of activity |
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Whata re the various mechanisms of actions for antimicrobial drugs?
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-cell wall synthesis
-cell membrane function -nucleic acid synthesis and replication -protein sysntheis -synthesis of central metabolites |
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What are the various chemical structures of antimicrobial drugs?
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-B-lactam (penicillins, cephalosporins, carbapenems, and monobactams)
-flouroquinolones (ciprofloxacin) -sulfoamides (sulfadiazine) -aminoglycosides (gentamicine) -macrolides (erythromycin) |
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Whata re various spectrum of activities for antimicrobial drugs?
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-gram-positive cocci
-gram-negatives -anaerobes -pseudomonas -fungi -viruses -parasites |
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What are the main characteristsics of preservatives?
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-used to prevent the overgrowth of bacteria and fungi in pharmaceutical products, laboratory asera and reagents, cosmetic products, and contact lenses
-should not be irritant or toxic to tissues to which they will be applied -must be effective -must have sufficent solubility and stability |
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What are the various biological properties of antimicrobial drugs?
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-antibiotic-produced by microorganism
-semi-synthetic drugs-derrivatives of AB-slightly modified -synthetic drugs- organic chemicals, nearly all antiviral drugs |
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What are commonly used preservative agents?
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-benzoic acid and salts
-parabens -sorbic acid and salts -benzyl alcohol |
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Why are benzoic acid and salts considered preservative agents?
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-has good solubility
-occur naturally in many plant and animal speciues -slightly soluble in water but more soluble in alcohol and otger polar organic solvents -used in preservative in food, drugs, and personal products -sodium benzoate is used preferably as one of the principal preservatives in foods and beverages (but in limited concentration) |
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How are parabens considered a preservative agent?
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-commonly used in cosmetics
-alkyl esters of p-hydroxybenzoic acid -common names are methylparaben, ethylparaben, propylparaben, and butylparaben -used as antifungal preservatives -mimic estrogen activity in human body -drive breast cancer in deoderant |
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How is sorbic acid and salts considered a preservative?
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-salt preferred over acid due to solubility
-poisioning can occur if too high of a concnetration -used as an antifungal preservative |
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How is benzyl alcohol considered a preservative?
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-prohibited in children since 1982 and allergy patients
-very toxic (can casue hypotension and vasodilation with major adverse effects -knowna s phenylcarbinol and pheynl methanol -used as a bacteriostatic preservatifve in parenteral medications |
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What are the two types of germicides?
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-disinfectants
-antiseptics |
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What are disinfectants?
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- for non-living tissues--> surfaces
-strong chemical agents that inhibit or kill microorganisms -prevent infection by reducing the number of potentially infective organisms by killing,removing, or diluting them |
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What are antiseptics?
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-can be used on liviing tissue
-disinfecting agents with low toxicity fro host cells -can be used directly on the skin, mucous membranes or wounds |
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What are 3 classes of disinfectants?
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high level (more powerful, destroy microbacterial, fungi, other bacteria, but not spores)
-intermerdiate level (most viruses and fungi never spores) -low level (no mycobacteri, wiull kill enveloped virues such as HIV) |
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What is antisepsis?
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-application of an agent to living tissue for the purpose of preventing infection
|
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What is decontamination?
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-destruction or marked reduction in number or activity of microorganisms
|
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What is sanitation?
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-reduction of microbial load on an inanimate surface to a level considered acceptable for oublic health pruposes
|
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What is sterlization?
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-a process intended to kill or remove all types of microroganisms, including spores, and usually including viruses with an acceptable low porbability of survival
|
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What is pasteruization?
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-a process that kills nonsporulating microorganisms byt hot water or steam at 65-100 degrees C
|
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What are commonly used anti-infective agents?
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-alcohol and related compounds
-phenols and their derivative -peroxygen agents (hydrogen peroxide) -halogen containign compounds -cationic surfactants |
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How is alcohol and related compounds a commonly used anti-infective agent? related compounds? disadvantages?
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-ethanol and isopropanol are most frequently used
-killing vegetative bacteria, mycobacterium tuberculosis, fungi, and inactivating lipophilic viruses -bactericidal at 60-80% concentration -related compounds are formaldehyde and glutaraldehyde -expensive -evaporate quickly -needs time to work -causes irritation |
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How are phenols and their derivatives common used anti-infective agents?
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-not effective for spores or non-envelope viruses
-phenol itself is no longer uses becuase of corrosive effect on tissue, it;s toxicity when absorbed is carcinogenic -mixtures of phenolic deriuvatvives are often used -bactericidal and fungicidal, disrupt cell walls and membrane, and inactivates enzymes -used for hard surface decontamination in hopsitals and laboratories |
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How is hydrogen peroxide a commonly used anti-infective agent?
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-have high killing activity against bacteria, sporesm viruses, and fungi
-not toxic and do not injure environment -cheap and very effective -fast working and not very stable |
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What halogen containign compounds are commonly used anti-infective agents?
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-iodine
-iodophors -chlorine |
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How is iodine a commonly used anti-infective agent?
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-oldest and quickest
-most active antiseptic for intact skin -used in various solutions: 2%-5% |
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How are iodophors a commonly used anti-infective agent?
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-complex of iodine with polyvinyl pyrolidone
-kill vegetative bacteria, mycobacteria, fungi, and lipid-containing viruses -used as antiseptics adn disinfectants |
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How is chlorine a commonly used anti-infective agent?
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-universal disinfectant
-very cheap adn fast acting -5.25% sodium hypochlorite is rtypical formulation for household bleach -forms hypochlorous acid in water -chlorine dioxide and chloramine T are alternative compounds |
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What are considered cationic surfactants for anti-infecting agents?
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--soluble in water and exhibit surface active properties
-each molecule has a hydrophilic head and hydrophilic tail -disrupt microorganisms cell processes and used as a germicide and sanitizer -include dyes, mercury compounds, and nitrofuran derivatives |
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What is the gram stain?
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-fast and accurate process
-frequently used -the different stains are ther result of differences in the cell walls of gram-positive and gram negative bacteria |
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What are common sites of invasion for gram-positive bacteria?
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-skin (wounds, surgical sites, indwelling catheters), throat, lungs (pneumonia and adult bacterial meningitis)
|
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Whata re common sites of invasion for gram-negative bacteria?
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-urinary tract, lungs (pneumonia), CNS (meningitis), sexually transmitted diseases (gonorrhea)
|
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What are gram positive bacteria?
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-have 2 layers:
--inner cytoiplasmic membrane --outer thick peptidoglycan layer (60-100%) -low lipid content -no porin channel -vulnerable to lysozyme and penicillin attack -has endotoxins -peptidoglycan doesn't block the diffusion fo small molcules such as antibiotics |
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Whata re gram negative bacteria?
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-has 3 layers:
--inner cytoplasmic membrane --thin peptidoglycan layer (5-10%) --outer membrane with lipopolysaccharide -high lipid content -porin channel -resistant to lysozyme and penicillin attack |
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What are mycobacteria?
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-weakly gram-positive by acid fast stain (tuberculosis and leprosy)
|
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Whata re bacterial cell wall inhibitors?
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-two important classes of antibiotics in this group are the B-lactams and glycopeptides
-prevent bacterial cell wall synthesis or repair of cell wall -bacterialcidal have selective toxicity |
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What is the mechanisms of action of bacterial cell wall inhibitors?
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-alanine added to CHO-tripeptide--> "T" shapped cell wall precursor (D-cycloserine)
-precursor transported across plasma membrane by carrier (vancomycin) -carrier recycled back into cell to carry other precursors (bacitracin) -precursor linked to existing cell wall by transpeptidase (penicillins, cephalosporins) |
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What are B-lactams of cell wall inhibitors?
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-include penicillins, cephalosporins, the monobactams, and the carbapenems
-all B-lactams have a beta-lactam ring (key to inhibition process) |
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What are the penicillins of cell wall inhibition?
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-to be effective the beta-lactams must penetrate the cell layers, keep its beta-lactam ring intact, bind to the transpeptidase
-antibiotic resistance is major problem in the treatment of the bacterial infections (B-lactamase activity, mutations, impaired penetration of drug, efflux) -can casue anaphylactic reaction (loos of ability to maintain blood pressure) -include penicillin G, penicillin V, methicillin, nafcillin, and isoxazolyl penicllins (oxacillin, cloxacillin, an dcicloxacillin), ampicillin, amoxicillin, carbencillin, piperacillin, ticaracillin, a nd mezlocillin |
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What is penicillin G?
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-given by IM or IV
-sensitive to beta lactamase |
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What is peniciilin V?
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-oral form of penicillin
-acid stable -still used in pneumonia caused by streptococcus pneumoniae |
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What is methicillin, nafcillin, and isoxazolyl penicillins (oxacillin, cloxacillin, and dicloxicillin)?
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-semi-synthetic, p[enicillinase-resistant penicillins
-used for gram-positive bacteria -methicilin, nafcillin, and oxacillin given by IV -cloxacillin, adn dicloxacillin is given oral |
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What is ampicillin and amoxicillin?
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-haeva broad spectrum of action but are B-lactamase sensitive
-use "amp-gent" combo which is IV ampicillin and aminoglycosides (gentamicin) |
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What are carbencillin, piperacillin, ticarcillin, and mezlocillin?
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-sensitive to penicillinases
|
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What are cephalosporins?
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-5-10% of patients with allergy to penicillin also ahve reaction to cephalosporin
-more resitant to beta-lactamases than penicllins -MRSA is resistant to all cephalosporins -include dirst and second generation |
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Whata re first generation cephalosporins?
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-cefazolin, cephalexin, cefadroxil, cepharadine, cephapirin, and cephalothin
-excellant gram-positive coverage -excellant for skin infection -beta-lactamase sensitive |
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What are second generation cephalosporins?
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-cefuroxime, cefotetan, cefoxitin, cefamandole, cefaclor, cefmetazole, cefonicin, cefprozil, loracarbef, and cefdinir
-have broader gram-negative coverage -generalyl more resistant to B-lactamase |
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What are the third generation cephalosporins and characteristics?
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-ceftazidine, ceftriazone, ceftizoxime, cefotaxime, cefixime, cefoperazone, cefpodozine, and ceftibuten
-have expanded gram-negative coverage -used to treat a wide variety of serious infections when other drugs fail -ceftriaxone is an excellant choice for meningitis (penetrates into cerebralspinal fluid) |
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What is the fourth generation of cephalosporins?
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-cefepime
-more resistant to B-lactamases -clinical role is similar to that of third-generation |
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What is Aztreonam as an antibacterial?
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-monobactam
-for gram-negative bacteria only -minimal cross-reactivity with penicillins -crosses blood-brain barrier, joints -B-lactamase resistant -good combo with vancomycin and clindamycin for braod-spectrum coverage |
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What is imipenem and meropenem as antibacterials?
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-carbapenems
-haev the broadest spectrum in coverage -B-lactamaase resistant, including ESBL's (extended spectrum beta lactamases) -MRSA is resistant to carbapenems -given with Cilastatin (kidney dihydropeptidase inhibitor) |
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What is vancomycin as an antibacterial?
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-glycopeptides
-does not contain a B-lactam ring (therefore B-lactamase resistant) -binds to cell wall precursor (pentapeptide, at a step earlier than penicillin) and prevents transfer across plasma membrane -bactericidal (cell wall inhibitor) -covers all gram-posivtive bacteria, even MRSA -is not absorbed orally |
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What are drugs that work inside the cells?
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-targets protein synthesis, genetic code, bacterial ribosomes, bacterial RNA polymerase, DNA gyrase, and folic acid metabolism
-can damaage eukaryotic DNA therefore sometimes carcinogenic |
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What antibiotics inhibit bacterial protein synthesis?
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-most of these drugs are bacteriostatic
-animoglycosides are bactericidal -prokaryotic 70S ribosome consists of a 30S and a 50S subunit -each composed of rRNA and numerous protein |
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What antimicrobial drugs target the 30S rubosome subunit?
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-tetracyclines
-aminoglycosides |
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What are tetracyclines?
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-antimicrobial drug that targets the 30S subunit
-do not give during pregnancy -cross placenta and excreted in milk -binds to calcium (cone) causing major deformities -differences in clinical efficacy are minor: pharmacokinetics of absorpotion, distribution, and excretion -binds to 30S subunit and inhibit protein synthesis -bacteriostatic -high selectivity derives froma ctive accumulation of drugs of bacteria but not in mammalian cells -has drug interaction with foods high in calcium (binds to bones an causes developmental abnomalies for 65+) |
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What are tetracyclines classified as and examples?
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-short acting: Chlortetracycline, tetracycline, and oxytetracycline
-intermediate-acting: demeclocycline and methacycline -long-lasting: doxycycline andf minocycline -doxycycline chelates cations poorly, so is better absorbed with food |
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What are aminoglycosides as antibacterials? Examples?
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-include streptomycin, neomycin, kanamycin, amikacin, gentamicin, tobramycin, sisomicin, netilmicin
-used to treat infections casued by gram-negative bacteria -binds to 30S subunit and inhibit protein synthesis -bactericidal, have concentration-depending killing -act synergistically with antibiotics, such as beta-lactams |
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What are streptomycin as an aminoglycoside? gentamicin? amikacin? neomycin? netilmicin?
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-streptomycin is the oldest one in the family
-gentamicin is most commonly used: effective against both gram-positive and gram-negative organisms; used in sever infections (sepsis and pneumonia) -amikacin has the broadest spectrum and is good for hospital infections -neomycin is used only topically (broad spectrum but very toxic) -netilmicin is given orally before GI surgery |
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What are anitmicrobial drugs that target the 50S subunit of ribosomes?
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-macrolides
-antimetabolites |
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What are macrolides? Examples of drugs?
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-named for their large lactone rings to which deoxy sugars are attached
-include erythromycin, azithromycin, and Clarithromycin -bind to 50S subunit and inhibit protein synthesis -commonly used as second line drugs for skina dn soft tissue infection (broad spectrum) -frequently used for upper respiratory tract infections -safest antibiotics |
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What are antimetabolites? How does it work as an antibacterial? Examples?
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-inhibit synthesis of nucleotides (purine and pyrimidiine) which are the building blocks of DNA and RNA
-good rugs for urinary tract infections -adverse effects are rare in persons without AIDS -bacteria need folate, when inhibited, kills bacterial cells -sulfonamides -trimethoprim |
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What are sulfonamides as an antimetabolite?
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-sulfamethoxazole
-looks like PABA inhibits PABA--> DHFR process -bacteriostatic -resistance can occur as a result of decreased permeability to the antibacterial drug; increased PABA production -sulfonamides are perhaps the most allergenic of antibiotics |
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What is trimethoprim as an antimetabolite?
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-inhibits bacterial dihydrofolic acid reductase (DHFR)
-bacteriostatic -useful in the treatment if chronic bacterial prostatitis |
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What is Bactrim as ana ntimetabolite?
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-trimethoprim and sulfamethoxazole act synergistically to kill many gram-positive and gram-negative bacteria
-don;t give while patient is on warfarin (dangerous) |
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What are antibiotics that inhibit bacterial DNA synthesis?
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-quinolones and flouroquinolones
-quinolones are synthetic antibiotics based on a nucleus of two fused six-membered rings -ythe addition of a flourine atom at position six of the quinolone antibiotics known as flouroquinolones -have become important as the penicillins and cephalosporins: based on safeness, oral absorption and penetration into tissues -act by inhibiting prokaryotic type II topoisomerases--DNA gyase (in gram - mostly) -flouroquinolones appear safe in pregnancy |
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What are first generation quinolones/flouroquinolones? seond generation? thrid? fourth? respiratory?
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-first: Nalidixic acid
-second: norfloxacin, ciprofloxacin, enoxacin, lomefloxacin, and ofloxacin (poor gram + coverage) -third: Gatifloxacin and levofloxacin (have greater affinity against gram-positive and atypical bacteria) -fourth: trovafloxacin, moxifloxacin, and gemifloxacin -respiratory: levofloxacin, gatifloxacin, gemifloxacin, and moxifloxacin (mostly used ffor gram negative) |
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What is isoniazid as a drug used to treat tubercuosis?
|
-synthetic
-will penetrate macrophage to deal with bacteria inside -prodrug actiuvated by catalase-peroxidase -bactrerial-cidal in dividing mycobacteria -bacterial-static when resting -inhbitis synthesis of mycolic acids once drug is activated -widely distributed to all tissues and fluids within the body -associated with hepatitis peripheral neuropathy -give with vitamin 6 |
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What is rifampin as a drug to treat tuberculosis?
|
-semi-synthetic
-wide spectrum antibiotic, most notably against gram-positive bacteria and TB -bacterialcidal -inhibits RNA synthesis -adverse reactions: induces cytochrome P450, anticoagulant, can't use oral contraceptives, and anticonvulsants are less effective |
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What is rifabutin as a drug used for treatment of tuberculosis?
|
-very similar to rifampin ins tructure, antibacterial activity, metabolism, and adverse reactions
-induces cytochrome P450 less than rifampin |
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What is pyrazinamide as a drug used for treatment of tuberculosis?
|
-synthetic
-mechanism of action is unknown -given for no more than 2 months (liver toxicity) -avoid during pregnancy |
|
What is ethambutol as a drug used for treatment of tuberculosis?
|
-used for oral administration
-synthetic -active only against dividing bacteria -crosses the BBB only if the menines are inflamed (meningitis) -higher dose is recommended for treatment of tuberculous meningitis -can cause ocular toxicity: not used for young children |
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What are fixed-dose combinations of drugs used in the treatment of tuberculosis?
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-Rifamate= Isoniazed and Rifampin
-Rifater= isoniazed and rifampin and pyrazinamide |
|
How do you treat active tuberculosis?
|
-usually a 2 month intensive phase with isoniazed, rifampin, ethambutol and pyrazinamide, followed by 4 months of isoniazed and rifampin
-patients with TB meninitis, bone infections, or TB arthritis, treat for 12 months |
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How do you conduct treatment of PPD reactors?
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-isoniazed is usually given for 9 months
|
|
What is mycobacterium leprae (leprosy)?
|
-chronic disease
-rare in US/Canada -highest prevalence in India, Brazil, Burma, Indonesia, Madagascar, and Nepal (600 new cases per year) -grows beter in cooler body temperatures closer to skin surface -maninly contracted via inhalatiuon -impossible to grow ona rtificial media -intracellular pathogen -slow-growing: needs 20-30 days of generation time |
|
What drugs are used for the treatment of leprosy?
|
-Dapsone
-rifampin -clofazimine |
|
How is dapsone used as adrug in treatment of leprosy?
|
-same mechansism of action as sulfonamides
-blocks PHF suynthesis and inhibits folate synthesis -well-tolerated -well-absorbed |
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How is rifampin used as a drug in treatment of leprosy?
|
-highly effective in combination with dapsone or others
|
|
How is clofazimine used as a drug in treatment of leprosy?
|
-mechanism of action is unknown (binds DNA)
-resistance developes slowly |
|
How do you treat severe cases of leprosy?
|
-Rifampin, Dapsone, and Clofazimine used for a mininum of 2 years
|
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How do you treat less severe cases of leprosy?
|
-Rifampin and dapsone for 6 months
|
|
What is the biology of fungi?
|
-free-living organisms: yeasts, molds, and dimorphic fungi
-eukaryotic, heterotrophic organisms (need aerobic environment) -have ergosterol: essential sterol for fungi and target of anti-fungal drugs |
|
What is the pathophysiology of fungal infections?
|
-results from mycotoxin production, allergenicity, and tissue invasion
|
|
What are superficial fungal infections? treatment?
|
-tinea nigra (asymptomatic)
-pigment change of the skin -treat with shampoo containing selenium sulfide and imidazoles (tyopically) |
|
What are cutaenous fungal infections of the skin, hair and nails? treatments?
|
-dermatophytosis and candidiasis
-matophytic (live on dead layer) -fungi secrete keratinase which digetss keratin -casues scaling oif the skin, loss of hair, and crumbling of nails -treat dermatophytosis with Griseofulvin (for severe infections) and terbinafin -treat candidiasis with nystatin and clotrimazole in the mouth and miconazole for vaginitis |
|
What are subcutaneous fungal infections? treatment?
|
-following trauma to the skin, will enter body and remain localized
-treat with itraconazole and local excision |
|
What are symptomatic fungal infections? How it is like TB? Unlike?
|
-systemic mycosis
-caused by 3 dimorphic fungus (histoplasma, blasmycesma and coccidioides) -like TB: can be inhaled, primary infectuions in the lung -aymptomatic, mild, severe, or chronic lung infections -can disseminate hematogenously to distant site (meningitis) -unlike TB: no person-to-person transmission -fungi with spores -not acid-fast bacteria |
|
What are polyenes that are anti-fungal?
|
-amphotericin B
|
|
What is amphotericin B as an anti-fungal drug?
|
-1st line of drugs used to treat
-produced by soil actinomycetes -used for severe fungal infection -no oral absorption, only by IV (doesn;t cross BBB) -punches holes in ergosterol and increases membrane permeability--> causes death -causes renal toxicity, acute febrile reaction (fever), anemia, and inflammation of the vein -lipid formulation of drug tolerated better |
|
What is flucytosine as an anti-fungal drug?
|
-synthetic
-anti-metabolite -used in combination with amphotericin B to treat systemic mycoses (to avoid resistance) -large volume of distribution -inhibits DNA synthesis and cell division -causes bone marrow depression, nausea, vomiting, and diarrhea |
|
What are the azoles that treat fungi infections?
|
-synthetic compounds
-imidazoles: ketoconazole, miconazole, anmd clotrimazole -Triazoles: fluconazole, itraconazole, and voriconazole -micoanazole and clotrimazole are used for topical fungal infections -rest used for systemic fungal infections -block enzyme in ergosterol synthesis (leads to cell wall permeability) |
|
What is ketoconazole as an anti-fungal drug?
|
-has broad spectrum of activity
-largely replaced by the newer, more effective, lexx toxic triazoles |
|
What is fluconazole as an anti-fungal drug?
|
-most heavily used becasue less toxic with a very borad spectrum
-kills candida infections as well |
|
What is itraconazole as a anti-fungal drug?
|
-azole choice of treatment for dimorphic fungi
-has poor oral absorption |
|
What is voriconazole as an anti-fungal drug?
|
-newest triazole
-has broad activity -has excellant activity against fluconazole resistant Candidia species |
|
What are posaconazole and Ravuconazole as anti-fungal drugs?
|
-D. Glucan syntheis inhibitors
|
|
What are Caspofungin and micafungin as anti-fungal drugs?
|
-good candida drugs for IV administration
-inhibit 1,3 D-glucan synthase--> inhibits fungal cell wall synthesis |
|
What is terbinafine as an anti-fungal drug?
|
-blocks eergosterol synthesis-->inhibits fungal cell wall synthesis
-accumulates in nails -little potential for drug-drug interactions |
|
What is griseofulvin as an anti-fungal drug?
|
-isolated froma number of molds of the genus penicillium
-inactive against bacteria, yeast, and fungi that cause systemio disease -static rather than cidal; inhibits fungal mitosis -works very slowly -should be avoided in pregnancy |
|
What is nystatin as an anti-fungal drug?
|
-used in the treatment of oral abd vaginal candidiasis
-same mechanisms of action as amphotericin B -too toxic: used only topically |
|
What is viral morphology for RNA viruses?
|
-positive, negative, or retro (reverse)
-naked: Hepatitis A (cna be + or -) -enveloped: Hepatitis C (+), influeza (Types A, B, and C; -), mumps (-), rabies (-), and ebola (-) -complex coat: HIV (I and II) |
|
What is the viral morphology of DNA viruses?
|
-cannot be trasnlated directly into proteins
-naked: human pailloma -enveloped: Herpes (I and II), caricell-zoster, and hepatitis B -complex coat: small pox |
|
What is the step-by-step process of viral replication?
|
-attachment of the virus to the host cell and entry
-uncoating of viral nucleic acid -genome replication -maturation of viral particles -release from the cell |
|
What are antiviral drugs?
|
-only virustatic
-viral nucleotide analogs |
|
What is the herpes virus?
|
-herpes simplex virus type I infects mouth, face, skin, or brain
-herpes simplex virus type II: infects genitals, rectum, skin, and hands -varicella zoster virus causes chickenpox -cytomegalovirus casues life-threatening diease (pneumonia) or sight-threatening retinitis in immunocrompromised patients |
|
How is acyclovir used in treating herpes virus?
|
-highly selective inhbitior of replication
-guanine analogue -requires three phophorylation steps for activation -generally well tolerated -CMV less sensitive to it than HSV and VZV |
|
How is ganciclovir used in treating Herpes virus?
|
-synthesized derrivative of acyclovir
-not dependent on a virus-specific thymidine kinase for phosphorylation -was first drug liscenced for use against CMV -less selective than acyclovir and more toxic |
|
What are retro viruses?
|
-carry unique enzyme called reverse trasncriptase
-can casue cancer -example is HIV -spread by parenteral route, sexual activity, blood product transfusion, IV drug use, and transplacental spread -forms latent infections in humans -normal T-cell counts are 1000 cells/uL blood--> HIV infected has 60 cells/mL/year |
|
What are nucleoside reverse trasncirptase inhibitors for use against HIV?
|
-zidovudine
-didanosine -zalcitabine -stavudine -lamivudine -emtricitabine -abacavir |
|
What nucleotide reverse transcriptase inhibitors are used against HIV?
|
-tenofovir
|
|
What non-nucleotide reverse transcriptase inhibitors are used against HIV?
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-nevirapine
-delaviradine -efavirenz |
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What protease inhibitors are used against HIV?
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-sequinavir
-indinavir -ritonovir -nelfinavir -amprenavir -fosamprenavir -atazanavir -tipranavir -lopinavir |
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What entry inhibitors are used against HIV?
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-enfuvirtide
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What are preferred drug regimens used in treatment of HIV?
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-zidovudine and laivudine (combivir) and efavirenz
-tenofovir and emtricitabine (truvada) and efavirenz -combivir and lopinavir |
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What are the nucleoside reverse transcriptase inhibors of HIV treatment?
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-Zidovudine
-lamivudine -emtricitabine |
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What is combo thereapy used for?
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-prevent resistance
-lower toxicity -different drugs have different mechanisms of action -have synergic effect |
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What is zidovuidne as a nucleoside reverse transcriptase inhibitor for HIV treatment?
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-well studied
-prevention of maternal-fetal transmission of HIV -for HIV-positive pregnant women prenattally + 6 weeks for in fants post natally -reduces mortality and opportunistic infections (raises t-cell count) -delays progression to aids |
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How is lamivudine and emtricitabine used as a nucleoside reverse trasnscriptase inhibotr for HIV treatment?
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-newer generation formulation
-well-tolerated -used to treat patients with HIV/Hepatitis B co-infection |
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What are the non-nucleoside reverse transcriptase inhibors of HIV infections?
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-Nevirapine
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How is nevirapine a non-nucleoside reverse transcriptase inhibitor for HIV treatment?
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-frequently given to pregnant women
-an inducer of the cytochrome P450 system and metabolized |
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What are protease inhibitors of HIV treatment?
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-saquinavir
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How is saquinavir a protease inhibitor for HIV treatment?
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-associated with metabolic abnormalites (dyslipidemia, insulin resistance, and lipodystrophy)
-low oral bioavailability -fortovase is a soft gel formulation of saquinavir with enhanced bioavailability |
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What is the significance of the drug-drug interations with zidovudine?
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-should be used with caution if patient is on other drugs that could cause bone marrow supprsstion or toxicity
-such as doxorubiicin and amphotericin B |
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What is the hepatitis family virus? What drugs can be used to treat it?
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-viruses that primarily infect the liver
-interferon and nucleoside analogs (lamivudine, adefovir, and entacavir) were used for treatment -interferon and ribaviran were used for hepatitis C |
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How is lamivudine used as a nucleoside analog for treatment of hepatitis?
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-synergistsic with a variety of antiretrovial nucleoside analogs
-inhibits HBV DNA polymerase -has an excellant safety profile |
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How is ribavirin used for treatment of hepatitis?
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-phophorylated intracellularly by host cell enzymes
-oral bioavailability is about 64%, increases with high-fat meals |
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What is influenza? What drugs can be used against it?
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-classified by their core proteins
-type A infects huymans, other mamals, and birds -type B and C have only been isolated in humans adamantanes and neuramnidase are used to treat it |
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What are adamantanes in treating influenza?
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-amatadine and rimantadine (less toxic)
-inhibit uncoated of the viral RNA -active against influenza A virus only (very anrrow spectrum of action) -resistance develops in 50% of treated individuals |
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What are neuraminidases in treating influenza?
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-zanamivir and oseltamivir
-inhibit the realease of influenza virus from infected to new host cells -have activity against both influenza A and influenza B viruses -do not use zanamivir in patients with asthma or chronic destructive pulmonary disease |
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What are protozoa?
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-free-living, single-celled, eukaryotic
-10000 species are parasitic (trypanosomes and plasmodium) |
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What is malaria?
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-one of the most problematic protozoa disease
-up to 300-500 million cases a year resulting in 1-3 million deaths -causes periodic episodes of severe chills and high fevers at 48-72 hr intervals -vector for transmission is the female anopheles mosquito -chemoprophylaxis: vaccination |
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How is Chloroquine used to treat malaria?
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-drug of choice for both treatment and chemoprophylaxis (vaccination) of malaria
-synthetic 4-aminoquinoline formulated as the phosphate salt for oral use -mechanism of action remains controversial -usually very well tolerated, even with prolonged use -chloroquine-resistant areas: quinidine -both are safe in all trimesters of pregnancy |
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What are helminths? How do you treat them?
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-problem in tropical areas
-16 types of worms that cause significant infections in humans: 10 roundsworms and 6 flatworms -mechanism of action: exert an antichilinergic effect on the worms, causing paralysis and expulsion by peristalsis -includes: albendazole, mebendazole, and thiabendazole -also ivermectin (doesn't kill adult worm) |
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What are prions?
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-prion diseases are the transmissible spongiform encephalopathies
-leads to dementia, ataxia, myoclonic jerks, and death -have long incubation time, gradual increase in severity leading to death within months of onset, no host-immune response, non-inflammatory process in the brain (difficult to detect) -infectious agent consist of only prion proteins (PRNP) -no curative treatment currently available |
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How do you identify a microorganism?
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-gram stain (+, -, or acid fast)
-immunlogical methods -location of infection: -skin--> probably gram-positive-->use nafcillin, dicloxillin -urinary tract infection-->probably gram-negative--> use trimethoprim or sulfamethoxazole |
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How do you classify a host's status?
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-metabolic and pharmacokinetics consideration: renal function and hepatic function, CNS penetration
-allergy history\ -immune status -age -pregnancy |
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What is drug combination?
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-for unknown microbe and unavailable gram stain---> use broad spectrum antibiotics
-to prevent resistance--> may use 2 drugs with different mechanisms of action -for synergy--> the action of soem drugs make other drugs more effective |
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How does the development and spread of antimicrobial resistance occur?
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-by using antibiotics
-using antibiotics outside the field of medicine -taking antibiotics for viruses -using prescibed drugs improperly |
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What is the mechanism of action of antimicrobial resistance?
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-enzyme inhibition (b-lactamases)
-alterations of bacterial membranes -promotion of antibiotic efflux -alterations of bacterial protein targets -bypass of antibiotic inhibition |
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How do you decrease antibiotic resistance?
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-withhold antibiotics
-use narrowest spectrum antimicrobial drug -base decisions about broadness of empiric coverage on severity of illness |
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What are the agents of bioterrorism?
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-anthrax
-plague -tularemia -botulism -"viral fever" |