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133 Cards in this Set
- Front
- Back
What is an antibiotic?
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chemical substance produced by microorganisms, which has the capacity to inhibit growth & even destroy bacteria & other microorganisms, in dilute solutions
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What is the chemical substance produced by microorganisms, which has the capacity to inhibit growth & even destroy bacteria & other microorganisms, in dilute solutions?
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antibiotic
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Is this inhibitory or cidal?
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cidal
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Is this inhibitory or cidal?
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inhibitory
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What is inhibition?
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bacteriostatic
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What is killing?
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cidal
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Explain the significance of each term
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peak - highest concentration
MIC - "like the therapeutic level" when above it- it works when below it - no pharmacologic properties area under the curve - drug exposure |
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The higher the concentration of a drug you are given, the more....
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killing you are getting out of the drug
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What is the MIC?
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minimal inhibitory concentration:
lowest concentration of antibiotic to have a killing or inhibitory effect on bacteria |
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lowest concentration of antibiotic to have a killing or inhibitory effect on bacteria
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minimal inhibitory concentration
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What is the time above MIC effect?
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when you give doses of antibiotics, you give a dose, wait a period, then give a dose. Dosing interval is the time in between the two doses. "Time above MIC" is fraction of time above the MIC compared to total dosing interval.
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Antimicrobial agents target two broad regions. What are they?
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-cell wall, cell membrane
- intracellular targets |
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What are the beta lactam drugs?
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-penicilins
-cephalosporins -monobactams -carbapenems |
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These drugs are part of what category: penicilins, cephalosporins, monobactams, carbapenems
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beta lactams
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Why is the beta lactam ring signifcant?
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beta lactam ring is crucial for antibiotic
some bacteria break ring & inactivate antibiotic |
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What do all beta lactam drugs have in common?
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beta lactam ring
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What is the structure of penicillin?
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5 sided ring with S at top
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What is the structure of cephalosporins?
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6 sided w/ s at top
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What is structure of carbapenems?
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5 sided ring with c at top, trans side chain
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What is the structure of monobactams?
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no side ring, side chains
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5 sided ring w/ s at top
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penicillin
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6 sided ring w/ S at top
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cephalosporin
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5 sided ring w/ c at top
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carbapenems
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no side ring, side chains
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monobactams
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What is the Beta lactam MOA?
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-inhibits cell wall synthesis
- synthesis of peptidoglycan requires 30 enzymes - penicillins are dipeptides that competitively inhibit cross linkage of cell -look like d-alanyl-d-alanine -covalently bind to target |
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In a gram positive, where is the peptidoglycan?
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outside
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In a gram negative, where is the peptidoglycan?
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thinner peptidoglycan
side chains on antibiotic change permissibility of antibiotic though porins into cell |
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tell me about penicillin
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penicillin binds to PBP
-penicilin binding proteins transpeptidase is a PBP |
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what do autolysins do
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bacteria have autolysis that help remodel the cell wall
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bacteria have these to hel remodel the cell wall
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autolysins
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what is the natural penicillin
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penicillin G
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penicillin G is active against?
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-strep
-enterococci -T palladium - B burgdorferi -n meningitidis - actinomyces |
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procaine pen G is short acting and is active agains
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-strep
-mouth anaerobes -meningococcus -listeria |
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benzathine (long acting) only need small concentration; active against?
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-t palladium
-rheumatic fever prophylaxis |
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T/F Penicillin has poor inflammation into uninflamed meninges
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TRUE
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T/F penicillin can be used to treat meningitis when caused by bacteria.
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TRUE
penicillin has poor penetration of UNINFLAMED MENINGES BUT BUT BUT..... when its inflamed its different |
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Although staph aureus was at one point susceptible to penicillin it no longer is. Why?
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staph aurues acquired enzyme, penicillinase, that breaks the beta lactam ring ---> hence it is now penicillin resistant
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What are the penicillinase resistant penicillins?
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nafcillin
oxacillin methicillin p.o. dicloxacillin |
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what do these all have in common
nafcillin oxacillin methicillin p.o. dicloxacillin |
penicillinase resistant penicillins
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T/F the penicillinase resistant penicillins can be used to treat staph aureus
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TRUE
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What are the side effects of the penicillinase resistant penicillins?
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-leukopenia
-renal impairment |
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What b-lactam is the only one that is not renally cleared?
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naficillin which is bilary excreted
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What are the aminopenicillins?
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ampicillin & amoxicillin
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Ampicilin & amoxicilin are both
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aminopenicilins
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The aminopenicilins (ampicilin and amoxicilin) have some....
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gram negative activity
active against strep enterococcus listeria |
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what are the side effects of the aminopenicillins (ampicillin & amoxicillin)
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diarrhea & rash
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What are the anti-pseudomonal penicillins?
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-carboxypenicillins
-ureidopenicillins |
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What are some of the adverse effects associated w/ penicillins?
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-hypersensitivity
-rash -anaphylaxis -granulocytopenia -seizures |
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What is the MOA of the cephalosporins?
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-inhibits cell wall synthesis
- synthesis of peptidoglycan requires 30 enzymes - penicillins are dipeptides that competitively inhibit cross linkage of cell -look like d-alanyl-d-alanine -covalently bind to target |
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1)What are the 1st generation cephalosporins?
2) What are they active against? 3) What are they inactive against? |
1) cephalothoin, cefazolin, cephalexin
2) staph, strep, some gram negative 3) not pseudomonas poor anaerobe activity not active against enterococci |
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The 1st generation cephalosporins (cephalothin, cefazolin, cephalexin) are active against?
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staph
strep some gram negative |
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The 1st generation cephalosporins (cephalothin, cefazolin, cephalexin) are inactive against?
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pseudomonas
poor anaerobe activity not active against enterococci |
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1) What are the second generation cephalosporins? 2) How are the second generations different than the first generation? 3) Cefuroxime is active against...... 4) what are the oral drugs
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1) cefoxitin, cefotetan
2) more active against gram negative & anaerobes 3) active against ampicillin resistant H flu, penetrates into CSF 4) cefuroxime axetil, cefaclor, cefprozil, loracarbef |
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How are the second generation cephalosporins different than the 1st generation?
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more active against gram negative & anaerobes
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What is cefuroxime active against?
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-active against ampicillin resistnat H. flu
-penetrates into CSF |
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methyl-tetrazole-thiomethyl is a side chain @ position 3. W/ regards to the second generation of cephalosporins why is this significant?
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- associated w/ disulfiram-like runs
-hypoprothrombinemia - inhibition of vitamin K activation - associated w/ bleeding |
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the following are side effects of cephalosporin are attributed to what side chain: dilsufiram rxns, hypoprothrombinemia, inhibition of vitamin k activation, associated w/ bleeding
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cephalosporin side chain - MTT (methyl-tetrazole-thiomethyl)
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1) What are the 3rd generation cephalosporins? 2) What are they active against? 3) What are they less active against? 4) T/F They don't penetrate the CSF
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1) ceftazidimine, cefoperazone
2) good activity against gram negative including pseudomonas aeruginosa 3) less active against gram positives 4) FALSE; they do penetrate CSF |
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3rd generation cephalosporins are active against
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good activity against gram negative (including pseudomonas aeruginosa)
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3rd generation cephalosporins are less active against...
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gram positive activity
moderate gram positive activity |
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What is a fourth generation cephalosporin & what is it active against?
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cefepime
gram negatives including P. aeruginosa & gram positives |
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NONE of the cephalosporins are active against
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-enterococci
-MRSA -listeria -legionella |
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Ceftaroline is part of the advanced generation cephalosporins.
What makes it unique? |
active against MRSA
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What is the only cephalosporin active against MRSA
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ceftaroline
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What is an example of a monobactam drug?
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aztreonam
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aztreonam is a
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monobactam
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What are the monobactams active against? What are they inactive against
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active against
-gram negative rods including p. aeruginosa no activity against -gram positives or anaerobes |
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monobactams are active against
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gram negative rods including p. aeruginosa
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monobactams are inactive against
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gram positives or anaerobes
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What are some examples of carbapenems
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impinem
cilastatin ertapenem meropenem |
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the carbapenems have
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broad gram negative coverage
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impimen & meropenem are both active against
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pseudomonas aeruginosa
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these carbapenems are active against pseudomonas aeruginosa
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impinem
meropenem |
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which carbapenem is not active against pseudomonas aeruginosa
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ertapenem
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Tell me more about the carbapenem drug meropenem
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- increased gram negative activity
-somewhat less gram positive activity compared to impinem |
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which drug, impinem or meropenem is more active when it comes to gram positive activity
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impinem
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name a side effect of impinem
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impinem seizures
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what is the MOA for beta-lactamase inhibitors
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drugs that block a bacterial enzyme that produce beta-lactam resistance
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What are the beta-lactamase inhibitors?
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clavulinic acid
sulbactam tazobactam all inhibit beta lactamases |
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what do clavulanic acid, sulbactam, & tazobactam have in common?
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all are beta-lactamase inhibitors
used in combination w/ beta lactam antibiotic not antibacterial agents |
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clavulanate is a beta lactamase inhibitor.
given this why does augmentin work? |
augmentin is a combination of clavulanate & amoxicilin
amoxicilin is the actual antibiotic whereas clavulanate is merely the beta lactamase inhibitor clavulanate inhibits the bacterial enzyme enabling amoxicilin to do its work think of amoxicilin as the sword and clavulanate as the shield |
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What is an adverse effect of clavulanate?
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diarrhea
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Name a glycopeptide drug (isolated from soil in borneo)
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vancomycin
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Vancomycin is a glycopeptide drug. What is its mechanism?
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bactericidal
inhibits cell wall synthesis, binds to D-alanyl-D-alanine |
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Vancomycin is available both intravenously and orally. What is significant about oral dosage?
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poorly absorbed orally
oral medication only given in intestinal infections that require luminal treatment |
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What is vancomycin active against?
What is vancomycin inactive against? |
-active against most gram positive bacteria
-inactive against gram negative bacteria or anaerobes |
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Vancomycin is active against....
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gram positive bacteria
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vancomycin is inactive against
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gram negatives or anaerobes
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compared to anti-staphylococcal beta lactams, vancomycin is
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less efficacious against staph aureus
less rapidly bactericidal & clinically less efficacious |
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w/ regards to vancomycin use what new problem is emerging
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VISA & VRSA vancomycin
VISA- vancomycin intermediate staph aureus VRSA - vancomycin resistant staph aureus |
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What are the side effects of vancomycin use?
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-nephrotoxicity when used in combination w/ aminoglycoside
-red neck syndrome -ototoxicity, rash |
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1) How does fosfomycin work? 2) What is it active against?
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1) fosfomycin interferes w/ early step in peptidoglycan synthesis
2) active against gram positive & gram negative bacteria |
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how does fosfomycin work?
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-interferes w/ an early step in peptidoglycan synthesis
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What is fosfomycin active against?
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active against gram positive & gram negative bacteria
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What are some polypeptide antibiotics?
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-polymyxin
-polymyxin B -polymyxin E (colistin) |
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What is the MOA for the polypeptide antibiotics?
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-bactericidal
-polypeptides w/ poor diffusability - polymyxins are cationic detergents; disrupt osmotic integrity of cell membrane by interacting w/ its phospholipids & increasing cellular permeability |
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What are the polymyxins used against?
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-p aeruginosa
-other gram negatives except proteus, serratia, providencia, neisseria |
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Although the polymyxins are effective against p. aeruginosa and other gram negatives why are they rarely used systematically?
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nephrotoxic hence rarely used systematically
however resurgence in use in hospitals where there are multi drug resistant gram negative organisms |
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What are some lipopeptide drugs?
What is the MOA? |
daptomycin
-baceticidal, binds to bacterial membranes & cause rapid depolarization of membrane potential |
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the lipopeptide daptomycin is active against......
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staphylococci
streptococci enterococci including vancomycin resistant strains |
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bc daptomycin does not penetrate well into the lung....
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daptomycin is not indicated for the treatment of pneumonia
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daptomycin is not indicated for the treatment of pneumonia bc....
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it does not penetrate well into the lung
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aminoglycosides
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2 or more amino sugars joined in a glycosidic linkage to hexose
highly water soluble gentamicin tobramycin amikacin streptomycin (TB, enterococcus: synergy w/ penicillin) neomycin B (topical) |
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How do aminoglycosides get taken into bacterial cell?
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-bactericidal; concentration dependent killing
-uptake into bacterial cell dependent on electrochemical gradient of inner membrane; gradient generated by aerobic metabolism -drug inactive in anaerobic environment such as an abscess |
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why are aminoglycosides inactive in anaerobic environments
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-uptake into bacterial cell dependent on electrochemical gradient of inner membrane; gradient generated by aerobic metabolism
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what is the MOA for aminoglycosides?
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block protein synthesis by binding to 30s ribosome & blocks initiation of protein synthesis, misreading genetic code, premature termination of translation
-block protein synthesis by binding to 30s ribosome -blocks initiation of protein synthesis, misreading genetic code -premature termination of translations |
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what are aminogylcosides active against?
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gram negative rods
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what are aminoglycosides synergistic with?
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beta lactams
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aminoglycosides & beta lactams are
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synergistic
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What are some side effects of aminoglycosides?
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-nephrotoxic
-ototoxic (auditory & vestibular) -neomycin - severe nephrotoxicity precludes use as a parenternal agent -streptomycin more ototoxic -neuromuscular blockade |
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MLS macrolides, lincosamids, streptogramins
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isolated for ilolio phillipines
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what are some common macrocodes
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erythromycin
clarithromycin azithromycin dirithromycin |
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What are macrolides?
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14 membered carbon ring w/ an aminosurgar and a neutral sugar (cladinose)
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Tell me about erythromycin
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in an aqueous environment at a low pH undergoes internal rearrangements & forms inactive compounds
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MOA for macrolides
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-inhibits proteins synthesis; binds to 50s subunit of ribosome
-bacteriostatic |
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what is the spectrum of activity for macrolides
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-most gram positive cocci usually susceptible
-s. pneumoniae -group a beta hemolytic strep -staph -enterococcus is variable -c diphtheriae -mycoplasma -chlamydia -legionella |
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what is resistant to macrocodes
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-many anaerobes resistant
-gram negative rods usually resistant, except, moraxella catarrhalis |
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monotherapy with macrolides may lead to
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resistance
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what are the side effects of macrolides?
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-mainly GI, nausea, vomiting
-cardiac arrhythmias clarithromycin - metallic taste erythromycin estolate - cholestatic hepatitis |
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What are 2 lincosamide drugs?
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lincomycin
clindamycin |
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What is the MOA for the lincosamides?
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-inhibits proteins synthesis; binds to 50s subunit of ribosome
-bacteriostatic |
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What are lincosamides active against?
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-most strep & staph
-most anaerobes including bacteroides fragilis -good for aspiration pneumonia |
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What are the adverse effects of lincosamides
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-diarrhea, associated w/ superinfection w/ clostridium difficile
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what are some streptogramin drugs
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quinupristin (streptogramin B)
dalfopristin (streptogramin A) streptogramin A and B are synergistic |
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What is the MOA for streptogramins?
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-inhibit protein synthesis
-streptogramin B binds to ribosome @ a site that overlaps w/ macrolides & lincosamides -streptogramin A binds to ribosome @ a nearby site -Sg A & B synergistic |
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What are streptogramins active against?
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streptococci
staphylococci not active against E. faecalis |
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What are the adverse effects of streptogramins
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arthralgias
myalgias phlebitis |
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What are ketolides?
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14 membered macrolide ring w/ cladinose at position 3 replaced by KETO & 11 & 12 carbamate bridge
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What is an example of a ketolide drug?
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telithromycin
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telithromycin is a
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ketolide drug
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MOA for ketolides
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binds to ribosome near where macrolides bind (domain V) & binds to domain II of the 23S rRNA
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ketolides are active against
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strep
stap h flu active against macrolide resistant streptococcus pneumoniae |
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what are the side effects of ketolides?
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visual disturbances
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