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133 Cards in this Set

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What is an antibiotic?
chemical substance produced by microorganisms, which has the capacity to inhibit growth & even destroy bacteria & other microorganisms, in dilute solutions
What is the chemical substance produced by microorganisms, which has the capacity to inhibit growth & even destroy bacteria & other microorganisms, in dilute solutions?
antibiotic
Is this inhibitory or cidal?
Is this inhibitory or cidal?
cidal
Is this inhibitory or cidal?
Is this inhibitory or cidal?
inhibitory
What is inhibition?
bacteriostatic
What is killing?
cidal
Explain the significance of each term
Explain the significance of each term
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
The higher the concentration of a drug you are given, the more....
killing you are getting out of the drug
What is the MIC?
minimal inhibitory concentration:
lowest concentration of antibiotic to have a killing or inhibitory effect on bacteria
lowest concentration of antibiotic to have a killing or inhibitory effect on bacteria
minimal inhibitory concentration
What is the time above MIC effect?
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.
Antimicrobial agents target two broad regions. What are they?
-cell wall, cell membrane
- intracellular targets
What are the beta lactam drugs?
-penicilins
-cephalosporins
-monobactams
-carbapenems
These drugs are part of what category: penicilins, cephalosporins, monobactams, carbapenems
beta lactams
Why is the beta lactam ring signifcant?
beta lactam ring is crucial for antibiotic

some bacteria break ring & inactivate antibiotic
What do all beta lactam drugs have in common?
beta lactam ring
What is the structure of penicillin?
5 sided ring with S at top
What is the structure of cephalosporins?
6 sided w/ s at top
What is structure of carbapenems?
5 sided ring with c at top, trans side chain
What is the structure of monobactams?
no side ring, side chains
5 sided ring w/ s at top
penicillin
6 sided ring w/ S at top
cephalosporin
5 sided ring w/ c at top
carbapenems
no side ring, side chains
monobactams
What is the Beta lactam MOA?
-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
In a gram positive, where is the peptidoglycan?
outside
In a gram negative, where is the peptidoglycan?
thinner peptidoglycan
side chains on antibiotic change permissibility of antibiotic though porins into cell
tell me about penicillin
penicillin binds to PBP
-penicilin binding proteins
transpeptidase is a PBP
what do autolysins do
bacteria have autolysis that help remodel the cell wall
bacteria have these to hel remodel the cell wall
autolysins
what is the natural penicillin
penicillin G
penicillin G is active against?
-strep
-enterococci
-T palladium
- B burgdorferi
-n meningitidis
- actinomyces
procaine pen G is short acting and is active agains
-strep
-mouth anaerobes
-meningococcus
-listeria
benzathine (long acting) only need small concentration; active against?
-t palladium
-rheumatic fever prophylaxis
T/F Penicillin has poor inflammation into uninflamed meninges
TRUE
T/F penicillin can be used to treat meningitis when caused by bacteria.
TRUE

penicillin has poor penetration of UNINFLAMED MENINGES BUT BUT BUT.....

when its inflamed its different
Although staph aureus was at one point susceptible to penicillin it no longer is. Why?
staph aurues acquired enzyme, penicillinase, that breaks the beta lactam ring ---> hence it is now penicillin resistant
What are the penicillinase resistant penicillins?
nafcillin
oxacillin
methicillin
p.o. dicloxacillin
what do these all have in common
nafcillin
oxacillin
methicillin
p.o. dicloxacillin
penicillinase resistant penicillins
T/F the penicillinase resistant penicillins can be used to treat staph aureus
TRUE
What are the side effects of the penicillinase resistant penicillins?
-leukopenia
-renal impairment
What b-lactam is the only one that is not renally cleared?
naficillin which is bilary excreted
What are the aminopenicillins?
ampicillin & amoxicillin
Ampicilin & amoxicilin are both
aminopenicilins
The aminopenicilins (ampicilin and amoxicilin) have some....
gram negative activity

active against
strep
enterococcus
listeria
what are the side effects of the aminopenicillins (ampicillin & amoxicillin)
diarrhea & rash
What are the anti-pseudomonal penicillins?
-carboxypenicillins
-ureidopenicillins
What are some of the adverse effects associated w/ penicillins?
-hypersensitivity
-rash
-anaphylaxis
-granulocytopenia
-seizures
What is the MOA of the cephalosporins?
-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
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
The 1st generation cephalosporins (cephalothin, cefazolin, cephalexin) are active against?
staph
strep
some gram negative
The 1st generation cephalosporins (cephalothin, cefazolin, cephalexin) are inactive against?
pseudomonas
poor anaerobe activity
not active against enterococci
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
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
How are the second generation cephalosporins different than the 1st generation?
more active against gram negative & anaerobes
What is cefuroxime active against?
-active against ampicillin resistnat H. flu
-penetrates into CSF
methyl-tetrazole-thiomethyl is a side chain @ position 3. W/ regards to the second generation of cephalosporins why is this significant?
- associated w/ disulfiram-like runs
-hypoprothrombinemia
- inhibition of vitamin K activation
- associated w/ bleeding
the following are side effects of cephalosporin are attributed to what side chain: dilsufiram rxns, hypoprothrombinemia, inhibition of vitamin k activation, associated w/ bleeding
cephalosporin side chain - MTT (methyl-tetrazole-thiomethyl)
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
1) ceftazidimine, cefoperazone
2) good activity against gram negative including pseudomonas aeruginosa
3) less active against gram positives
4) FALSE; they do penetrate CSF
3rd generation cephalosporins are active against
good activity against gram negative (including pseudomonas aeruginosa)
3rd generation cephalosporins are less active against...
gram positive activity

moderate gram positive activity
What is a fourth generation cephalosporin & what is it active against?
cefepime

gram negatives including P. aeruginosa & gram positives
NONE of the cephalosporins are active against
-enterococci
-MRSA
-listeria
-legionella
Ceftaroline is part of the advanced generation cephalosporins.

What makes it unique?
active against MRSA
What is the only cephalosporin active against MRSA
ceftaroline
What is an example of a monobactam drug?
aztreonam
aztreonam is a
monobactam
What are the monobactams active against? What are they inactive against
active against
-gram negative rods including p. aeruginosa

no activity against
-gram positives or anaerobes
monobactams are active against
gram negative rods including p. aeruginosa
monobactams are inactive against
gram positives or anaerobes
What are some examples of carbapenems
impinem
cilastatin
ertapenem
meropenem
the carbapenems have
broad gram negative coverage
impimen & meropenem are both active against
pseudomonas aeruginosa
these carbapenems are active against pseudomonas aeruginosa
impinem
meropenem
which carbapenem is not active against pseudomonas aeruginosa
ertapenem
Tell me more about the carbapenem drug meropenem
- increased gram negative activity
-somewhat less gram positive activity compared to impinem
which drug, impinem or meropenem is more active when it comes to gram positive activity
impinem
name a side effect of impinem
impinem seizures
what is the MOA for beta-lactamase inhibitors
drugs that block a bacterial enzyme that produce beta-lactam resistance
What are the beta-lactamase inhibitors?
clavulinic acid
sulbactam
tazobactam

all inhibit beta lactamases
what do clavulanic acid, sulbactam, & tazobactam have in common?
all are beta-lactamase inhibitors
used in combination w/ beta lactam antibiotic
not antibacterial agents
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
What is an adverse effect of clavulanate?
diarrhea
Name a glycopeptide drug (isolated from soil in borneo)
vancomycin
Vancomycin is a glycopeptide drug. What is its mechanism?
bactericidal

inhibits cell wall synthesis, binds to D-alanyl-D-alanine
Vancomycin is available both intravenously and orally. What is significant about oral dosage?
poorly absorbed orally

oral medication only given in intestinal infections that require luminal treatment
What is vancomycin active against?
What is vancomycin inactive against?
-active against most gram positive bacteria

-inactive against gram negative bacteria or anaerobes
Vancomycin is active against....
gram positive bacteria
vancomycin is inactive against
gram negatives or anaerobes
compared to anti-staphylococcal beta lactams, vancomycin is
less efficacious against staph aureus

less rapidly bactericidal & clinically less efficacious
w/ regards to vancomycin use what new problem is emerging
VISA & VRSA vancomycin

VISA- vancomycin intermediate staph aureus
VRSA - vancomycin resistant staph aureus
What are the side effects of vancomycin use?
-nephrotoxicity when used in combination w/ aminoglycoside
-red neck syndrome
-ototoxicity, rash
1) How does fosfomycin work? 2) What is it active against?
1) fosfomycin interferes w/ early step in peptidoglycan synthesis
2) active against gram positive & gram negative bacteria
how does fosfomycin work?
-interferes w/ an early step in peptidoglycan synthesis
What is fosfomycin active against?
active against gram positive & gram negative bacteria
What are some polypeptide antibiotics?
-polymyxin
-polymyxin B
-polymyxin E (colistin)
What is the MOA for the polypeptide antibiotics?
-bactericidal
-polypeptides w/ poor diffusability
- polymyxins are cationic detergents; disrupt osmotic integrity of cell membrane by interacting w/ its phospholipids & increasing cellular permeability
What are the polymyxins used against?
-p aeruginosa
-other gram negatives

except proteus, serratia, providencia, neisseria
Although the polymyxins are effective against p. aeruginosa and other gram negatives why are they rarely used systematically?
nephrotoxic hence rarely used systematically

however resurgence in use in hospitals where there are multi drug resistant gram negative organisms
What are some lipopeptide drugs?

What is the MOA?
daptomycin

-baceticidal, binds to bacterial membranes & cause rapid depolarization of membrane potential
the lipopeptide daptomycin is active against......
staphylococci
streptococci
enterococci including vancomycin resistant strains
bc daptomycin does not penetrate well into the lung....
daptomycin is not indicated for the treatment of pneumonia
daptomycin is not indicated for the treatment of pneumonia bc....
it does not penetrate well into the lung
aminoglycosides
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)
How do aminoglycosides get taken into bacterial cell?
-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
why are aminoglycosides inactive in anaerobic environments
-uptake into bacterial cell dependent on electrochemical gradient of inner membrane; gradient generated by aerobic metabolism
what is the MOA for aminoglycosides?
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
what are aminogylcosides active against?
gram negative rods
what are aminoglycosides synergistic with?
beta lactams
aminoglycosides & beta lactams are
synergistic
What are some side effects of aminoglycosides?
-nephrotoxic
-ototoxic (auditory & vestibular)

-neomycin - severe nephrotoxicity precludes use as a parenternal agent
-streptomycin more ototoxic
-neuromuscular blockade
MLS macrolides, lincosamids, streptogramins
isolated for ilolio phillipines
what are some common macrocodes
erythromycin
clarithromycin
azithromycin
dirithromycin
What are macrolides?
14 membered carbon ring w/ an aminosurgar and a neutral sugar (cladinose)
Tell me about erythromycin
in an aqueous environment at a low pH undergoes internal rearrangements & forms inactive compounds
MOA for macrolides
-inhibits proteins synthesis; binds to 50s subunit of ribosome
-bacteriostatic
what is the spectrum of activity for macrolides
-most gram positive cocci usually susceptible
-s. pneumoniae
-group a beta hemolytic strep
-staph
-enterococcus is variable
-c diphtheriae
-mycoplasma
-chlamydia
-legionella
what is resistant to macrocodes
-many anaerobes resistant
-gram negative rods usually resistant, except, moraxella catarrhalis
monotherapy with macrolides may lead to
resistance
what are the side effects of macrolides?
-mainly GI, nausea, vomiting
-cardiac arrhythmias

clarithromycin - metallic taste
erythromycin estolate - cholestatic hepatitis
What are 2 lincosamide drugs?
lincomycin
clindamycin
What is the MOA for the lincosamides?
-inhibits proteins synthesis; binds to 50s subunit of ribosome
-bacteriostatic
What are lincosamides active against?
-most strep & staph
-most anaerobes including bacteroides fragilis
-good for aspiration pneumonia
What are the adverse effects of lincosamides
-diarrhea, associated w/ superinfection w/ clostridium difficile
what are some streptogramin drugs
quinupristin (streptogramin B)
dalfopristin (streptogramin A)

streptogramin A and B are synergistic
What is the MOA for streptogramins?
-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
What are streptogramins active against?
streptococci
staphylococci
not active against E. faecalis
What are the adverse effects of streptogramins
arthralgias
myalgias
phlebitis
What are ketolides?
14 membered macrolide ring w/ cladinose at position 3 replaced by KETO & 11 & 12 carbamate bridge
What is an example of a ketolide drug?
telithromycin
telithromycin is a
ketolide drug
MOA for ketolides
binds to ribosome near where macrolides bind (domain V) & binds to domain II of the 23S rRNA
ketolides are active against
strep
stap
h flu

active against macrolide resistant streptococcus pneumoniae
what are the side effects of ketolides?
visual disturbances