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77 Cards in this Set

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Name two classes of drugs that inhibit cell wall biosynthesis and one class of drugs that inhibits membrane potential
glycopeptide
beta lactams

lipopeptide antibiotics
name two glycopeptide antibiotics
vancomycin
teicoplanin
glycopeptides are ___ against gram positive cocci and ___ against gram positive rods; they are ___ against gram negatives
bacteriostatic- gram pos cocci
bactericidal- gram pos rods
non effective- gram negatives
Where is vancomycin's site and mechanism of action
binds D-ALA-D-ALA terminus of murine monomer
--> inhibits murine polymer synthesis by blocking attachment of repeating disaccharide subunits to pre-existing cell wall
name four reasons/conditions to use vancomycin
1. antibiotic resistant pseudomembranous colitis
2. antibiotic resistant staphylococcal enterocolitis
3. staph infection in beta-lactam sensitive patients- or when infection is resistant
4. strep infections in beta lactam sensitive patients, or when infection is resistant
how do bugs become resistant to vancomycin
acquire the ability to replace the terminal D-ala with D-lactate (acquire the van HAX gene)
name three benefits of teicoplanin over vancomycin
1. extened half-life
2. once daily dosing
3. no pain or tissue necrosis after IM injection
beta lactams are type ___ antibiotics
type 2:
bacteriocidal
time-dependent
no PAE
name three classes of beta lactams
1. penicillins
2. cephalosporins
3. carbapenems
where do penicillins come from
made by strains of the fungus penicillium
what is the common structural feature of penicillins
6-aminopenicillanic acid nucleus composed of a thiazolidine ring (pentagon) fused to a beta lactam ring (square)
why are penicllins provided as their Na or K salts
because they are strong acids, the salt improves their solubility
where is the active center of penicillins, the site of action of penicillinases, and the site of formation of the major antigenic determinants of penicillins
beta lactam ring
name four things that changing the R-group can do to the penicillin molecule
acid stability
sensitivity to penicllinase
antibacterial spectrum
potency
penicillin MOA
inhibit the formation of peptidoglycan crosslinks in the cell wall.

beta-lactam moiety of penicillin -> binds enzyme that links peptidoglycan molecules in the bacteria (prevents polymerization of subunits)->
prevents bacteria from multiplying by causing lysis when bacteria tries to divide
Where is the site of action for penicillinase?
for amidase?
penicillinase- between the C-N bond of the beta lactam ring
amidase- between the C-N bond of the C=O to the left of the lactam ring
penicillin G is acid/base labile.
__ of an oral dose is absorbed
good distribution except ___
in renal failure, half life ___
acid labile
1/3 absorbed
good distribution except CSF
renal failure- t1/2 INCREASES
What plays a role in hypersensitivity to penicillin G- renal secretion of unmetabolized, yet active, drug or hepatic metabolites, although inactive?
inactive hepatic metabolites
how do you delay absorption of penicillin G from intramuscular sites
add organic bases like procaine or benzathine
what is the drug of choice of syphillis
penicillin G + benzathine
What does delaying absorption of penicillin G do to the maximum blood level achieved
it is considerably lower for an equivalent dose
how do you delay elimination of penicillin G
administer probenecid- a competitive blocker of tubular secretion of organic acids
most active of the penicillins against Gram positive bacteria (non-penicillinase producers), acid labile
penicillin G
acid stable penicillin form with better absorption after oral administration
penicillin V
name four mechanisms of beta-lactam resistance
1. decreased affinity of penicillin binding proteins through mutation and recomb
2. decreased cell wall permeability
3. increased activity of penicillinases (beta-lactamases)
4. energy- dependent efflux pumps
methicillin
nafcillin
cloxacillin
penicillinase resistant penicillins
name two bugs that make exocellular beta-lactamase
staph aureus and s. epidermis
is methacillin given orally
no
what is methicillin resistance related to
failure to bind to penicillin binding proteins; organisms resistant are likely to be resistant to other penicillins and cephalosporins
ampicillin
amoxicillin
extended range penicillins
how do ampicillin and amoxicillin increase spectrum
better penetration of gram negative outer membrane and/or decreased susceptibility to gram negative penicillinases (but more susceptible to gram pos penicillinases)
which is more completely absorbed after oral administration- amoxicillin or ampicillin
amoxicillin
name 6 bugs that ampicillin and amoxicillin are good for
e. coli
p. mirabilis
h. influenza
salmonella
shigella
neisseria
carbenicillin
ticarcillin
anti-pseudomonal penicillins
name three bugs that are susceptible to carbenicillin and ticarcillin
p. aeruginosa
indole pos proteus
indole pos enterobacter
name an N-acyl derivative anti-pseudomonal penicillin (ureidopenicillin)
pipericillin
amoxicillin plus clavulanate
augmentin (add penicillin with a suicide inhibitor of beta-lactamase)
ticarcillin plus clavulanate
timentin (add penicillin with a suicide inhibitor of beta-lactamase)
ampicillin plus sulbactam
unasyn (add penicillin with a suicide inhibitor of beta-lactamase)
pipericillin plus tazobactam
Zosyn (add penicillin with a suicide inhibitor of beta-lactamase)
is penicillin itself antigenic
no- its polymers and metabolites can react with bacterial or tissue proteins to form antigenic conjugates
what is the major class of metabolites which act as antigenic determinants of penicillin
penicillinic acids
name five adverse effects of penicillins
1. allergic
2. diarrhea in kids
3. CV fluid overload
4. CNS effects in lg doses or renal failure
5. coag defects from inhibition of platelet activation and conversion of fibrinogen to fibrin
does a negative skin test for penicillin hypersensitivity guarantee the absence of an anaphylactic response
no- it only predicts 95% of IgE mediated hypersensitivity
What is used to detect penicilloyl-specific IgE antibodies without skin testing
Rast- radioimmunoassay testing
cephalosporin MOA

new cephalosporins have a wider range of activity because of resistance to...
type II bactericidal- time dependent, no PAE

gram negative penicillinases
cefadroxil
cephalexin
cefazolin
cephadrine
first generation (narrow spectrum) cephalosporin
first generation cephalosporins have...
___ against gram pos's
___ against gram neg's
___ against methicillin-resistant S. aureus
good activity- gram pos
moderate activity- gram neg
not effective- methicillin resistant S. aureus
1st gen cephalosporins may not be drug of choice for active infection because they...
but may be drugs of choice for...
don't penetrate CSF

surgical prophylaxis
cefotetan
cefoxitin
cefuroxime
cefuroxime axetil
carbacephem
second generation (increased activity against gram neg, decreased activity against gram pos) cephalosporins
good activity against B. fragilis, and anaerobic organisms
cefotetan
similar spectrum of action to cefotetan; both used for prophylaxis during intra-abdominal surgery
cefoxitin
effective against h. influenzae and k. penumoniae; used to treat community acquired pneumonia
cefuroxime
orally active prodrug axetil form of cefuroxime
cefuroxime axetil
cephalosporin derivative with spectrum of activity comparable to that of cefaclor or amoxicillin/clavulanate
carbacephem
cefotaxime
cefpodoxime
ceftazidime
ceftriaxone
3rd gen (good penetration to CNS) cephalosporin
high activity against many gram negative enteric bacteria
cefotaxime
orally active with wide spectrum of action; useful for URTI and UTI
cefpodoxime
indicated primarily for multidrug resistant gram negative infections; particularly those caused by pseudomonas
ceftazidime
similar spectrum to cefotaxime, 8 hr serum half life instead of 1 hr, drug of choice for n. gonorrhea and b. burgdorferi with CNS involvement
ceftriaxone
cefepime
4th generation cephalosporin
similar to ceftazidime in activity against pseudomonas and other gram negative organisms;
better than 3rd generation cephalosporins against gram pos organisms because of its resistance to chromosomally-encoded beta-lactamase; orally active
cefepime
name 6 adverse effects of cephalosporins
1. diarrhea and GI upset
2. vit K def
3. nephrotoxicity
4. suprainfection
5. hypersensitivity reax
6. disulfiram-alcohol reax
imipenem
meropenem
ertapenem
monobactam
carbapenems (also beta-lactam antibiotics --> type II bactericidal, time-dependent; no PAE)
extremely broad anti-bacterial spectrum;
resistant to beta-lactamase
not resistant to metallo-beta-lactamase
cross-allergenicity with penicillin
imipenem
imipenem with cilastatin
primaxin- because imipenem alone is rapidly hydrolyzed by renal tubule dipeptidase
structurally related to imipenem, but less susceptible to hydrolysis by renal tubule dipeptidase
meropenem
longer plasma half life than meropenem -> permitting once-daily dosing
ertapenem
excellent activity against gram neg
poor activity against gram pos
little cross-allergenicity with other beta-lactam drugs
monobactam
daptomycin
lipopeptide antibiotic- inhibits cell membrane potential
used for tx of complicated skin infections by aerobic, gram pos's
daptomycin
daptomycin MOA
bactericidal type I
concentration dependent, significant PAE

binds to bacterial membranes and forms channels in a calcium-dependent manner leading to rapid membrane depolarization -> inhibiting protein, DNA, and RNA synthesis
bactericidal against vancomycin resistant enterococci
daptomycin
how do you give daptomycin and does it cross the BBB
injection only

no
how do bugs get daptomycin resistance
so far, they haven't
combinations of beta lactams with inhbitors of bacterial beta lactamases, such as ___ improves the effectiveness of the antibiotic
clavulanate
imipenem, a broad-spectrum antibiotic, is rapidly degraded by the renal ___, however, a related carbapenem, ___, is resistant to this degradation
renal tubule dipeptidase

meropenem