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Pharm Exam 3
Antimicrobials I
137
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Professional
02/25/2011

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Term
Antibiotics are substances produced by some microorganisms capable of
a. destroying/killing (bacteri_____) or
b. inhibiting the growth (bacteri______)
Definition
cidal
ostatic
Term
What is the IC50?
Definition
IC 50 – where 50% of bacteria cells are killed or where 50% 0f the host cells are killed
Term
trimethoprim: order of effectiveness against human, protozoal, and bacterial cells
Definition
most effective against bacteria (0.005)
intermediate effective against protozoa (0.07)
least effective against human cell (260)
Term
pyrimethamine: order of effectiveness against human, protozoal, and bacterial cells
Definition
most effective against protozoal (0.0005)
intermediate effective against human cell (0.7)
least effective against bacteria (2.5)
Term
methotrexate: order of effectiveness against human, protozoal, and bacterial cells
Definition
most effective against human cell (0.001)
intermediate effective against protozoa (~0.1)
inactive against bacteria
Term
One measure, which relates the dose of a drug required to produce a desired effect to that which produces an undesired effect, is the _____
Definition
therapeutic index.
Term
Therapeutic index is defined by ____/_____
Definition
TD50/ED50
Term
Toxic dose (TD50): means what?
Effective dose (ED50): means what?
Definition
Dose required to produce a particular toxic effect in 50% of animals

Dose at which 50% of individuals exhibit a specified therapeutic effect
Term
High therapeutic index: _____ TD50 and ____ ED50
Definition
High
low
Term
the > the therapeutic index, the > the _____ of a drug
Definition
efficacy
Term
In general, agents that are active against the _____ are “cidal”
Definition
cell wall
Term
Cidal agents required for ________ patients and those with _______, _______, and infections in ______ cancer patients
Definition
immunocompromised
endocarditis
meningitis
neutropenic
Term
Concentration-dependent killing (bacteriocidal):
Rate and extent of killing depends on drug _____
Examples: _______,_______
Definition
concentration
Aminoglycosides, quinolones
Term
Time-dependent killing (bacteriocidal):
Drug concentration must be maintained above a ______
Examples: _____,______
Definition
minimum bacteriocidal concentration (MBC)
Beta-lactams, vancomycin
Term
with Concentration-dependent killing, the rate of bacterial killing _______ as the conc. of drug increases
Definition
increases
Term
with Time-dependent killing, the rate of bacterial killing _________ as the conc. of drug increases
Definition
does not significantly increase
Term
In general, ____ synthesis inhibitors are bacteriostatic (but _______ are Bactericidal)
Definition
protein
aminoglycosides
Term
“Cidal” versus”static is relative
Example: penicillin is only bacterio_____ versus enterococci. When combined with an aminoglycoside like gentamicin, bacterio______ activity results. Due to increased _____ of gentamicin. Conversely, gentamicin is ineffective against enterococci in the absence of penicillin. This drug-drug enhancement is called ______.
Definition
bacteriostatic
bacteriocidal
permeability
synergism
Term
Bacterial or tumor sensitive implies that the tumor or bacterial cell is .....
Definition
readily inhibited by the concentration of drug.
Term
Bacterial or tumor resistance refers to the ability of a cell to ......
Definition
grow in the presence of an antibiotic or cancer chemotherapeutic agent.

Resistant cells have a
growth advantage!!!!!!
Term
Combinations of antimicrobrial agents can be (3)
Definition
a. synergistic
b. additive
c. antagonistic
Term
example:
A penicillin and an aminoglycoside may kill enterococcus more effectively than either component alone because inhibition of cell wall synthesis by penicillin allows passage of the aminoglycoside to its target in the cell.

This is an example of a _________ combination
Definition
Synergistic
Term
example:
The inhibition of growth by bacteriostatic agents can prevent the lethal activity of penicillin because it is effective only on dividing cells. Therefore, bacteriostatic and bactericidal agents are not used together.


This is an example of _______ combination
Definition
antagonistic
Term
Combination Pharmacotherapy, even if it is additive, is important because it decreases the probability of the emergence of a _______.
Definition
resistant mutant.
Term
If you don’t know causative organism, agent with a _____ spectrum of activity is usually required
Definition
broader
Term
Don’t put bacteriocidal & bacteriostatic together. Static will stop growth, but for cidal agent to work, there has to be a growing cell so if w/ a static, a cidal cannot work
Ex. Don’t give an aminoglycoside w/ tetracycline
Definition
Term
MIC-minimum inhibitory concentration?....
Definition
The lowest concentration of antibiotic that will inhibit the growth of an organism
Term
Organism is usually considered “susceptible” if blood levels of drug ___-___ times the MIC can be attained without appreciable side effects
Definition
2-4
Term
MBC–minimum bactericidal concentration or minimum lethal concentration (MLC)?...
Definition
lowest conc. of drug that kills 99.9% of bacteria
Term
Susceptibility Testing: Kirby-Bauer disk diffusion test?...
Definition
A culture plate is seeded with a bacterial isolate.
Disks are placed containing different antibiotics.
Clear zones around disks indicate bug is susceptible & antibiotic is effective.
Term
____ spectrum: Only specific types of bacteria inhibited or killed. Example: only gram (+) cocci
Definition
Narrow
Term
_____ spectrum: Many different types of bacteria are inhibited and/or killed. Example: gram (+) cocci, and bacilli, and many gram (-) bacteria
Definition
Broad
Term
inhibitors of metabolism: (2)
Definition
Sulfonamides
Trimethoprim

These are competitive inhibitors of the enzyme involved in folate synthesis. -> important nutrient for pregnant women
Term
Inhibitors of cell wall synthesis: (2)
Definition
B-lactams
Vancomycin
Term
Inhibitors of protein synthesis: (5)
Definition
tetracyclines
aminoglycosides
macrolides
clindamycin
cloramphenicol
Term
inhibitors of nucleic acid function or synthesis (2)
Definition
Fluorquinolones
Rifampin
Term
inhibitors of cell membrane function (2)
Definition
Isoniazid
Amphotericin B
Term
Penicillin G is what type of drug?
Definition
Natural Penicillin (100% resistant to Staphylococci)
Term
Penicillin V is what type of drug?
Definition
Natural Penicillin (100% resistant to Staphylococci)
Term
Benzathine or procaine Penicillin G is what type of drug?
Definition
Natural Penicillin (100% resistant to Staphylococci)
Term
Methicillin is what type of drug?
Definition
Antistaphylococcal Penicillins
Term
nafcillin is what type of drug?
Definition
Antistaphylococcal Penicillins
Term
dicloxacillin is what type of drug?
Definition
Antistaphylococcal Penicillins
Term
Oxacillin is what type of drug?
Definition
Antistaphylococcal Penicillins
Term
cloxacillin is what type of drug?
Definition
Antistaphylococcal Penicillins
Term
floxacillin is what type of drug?
Definition
Antistaphylococcal Penicillins
Term
Ampicillin is what type of druG?
Definition
Extended Spectrum Penicillin
Term
Amoxicillin is what type of drug?
Definition
Extended Spectrum Penicillin
Term
Carbenicillin is what type of drug?
Definition
Anti-Pseudomonal Penicillin
Term
piperacillin is what type of drug?
Definition
Anti-Pseudomonal Penicillin
Term
ticarcillin is what type of drug?
Definition
Anti-Pseudomonal Penicillin
Term
Mezlocillin is what type of drug?
Definition
Anti-Pseudomonal Penicillin
Term
azlocillin is what type of drug?
Definition
Anti-Pseudomonal Penicillin
Term
All penicillins are _____ antibiotics
Definition
Beta-lactam
Term
Penicillins have __-member b-lactam ring
Definition
5
Term
Cephalosporins have __-member b-lactam ring
Definition
6
Term
Carbapenem and monobactams have _____ rings
Definition
modified
Term
_____ of the b-lactams determine stability to stomach acid, antimicrobial spectrum, and susceptibility to b-lactamases
Definition
Side changes
Term
Penicillins: Mechanism of Action:
Inhibit ___ step of bacterial ____ synthesis
Inhibit cross linking of ____
Exposes membrane to _____
This makes these drugs bacterio_____
Definition
last
cell wall
peptides
osmotic lysis
bacteriocidal
Term
Penicillins are Inactive against organisms that lack a cell wall, e.g., (4)
Definition
mycobacteria
protozoa
fungi
viruses
Term
Gram + bacteria have a bigger _______ layer than gram -
Definition
peptidoglycan/cell wall
Term
Penicillin better against gram___ b/c it doesn’t have an outer membrane, w/ gram__ would have to pass through lipid bilayer to get to the cell wall
Definition
+
-
Term
Gram ___ have an outer lipid membrane layer
Definition
-
Term
_______ are enzymes (transpeptidase) involved in cell wall synthesis
Definition
Penicillin Binding Proteins (PBPs)
Term
Penicillins bind to ____ and inhibit them
Definition
PBPs
Term
Alterations (or mutations ) in ___ of Staphylococcus aureus confers resistance = Methicillin-resistant S. aureus (MRSA)
Definition
PBP
Term
Penicillin inhibits _____ by binding to PBP
Definition
peptide cross-linking
Term
_______ are a group of enzymes that exist in all bacteria containing peptidoglycan. The peptidoglycan matrix is very rigid, so these enzymes break down the peptidoglycan matrix in small sections so that growth and division of cells can occur. In the presence of Penicillins, cell wall breakdown proceeds in the absence of cell wall synthesis, resulting in cell ____
Definition
Autolysins
lysis
Term
Penicillin G: Spectrum
Gram (__) organisms are usually susceptible
Acquired resistance can be a problem
Definition
+
Term
Penicillin G: Spectrum:
G(+) cocci – (4)
G (+) bacilli – (4)
Definition
S. aureus, Strep. pneumoniae, Strep. pyrogenes, Strep. viridans

Bacillus anthracis (anthrax), Clostridium perfringens, Corynebacterium diphtheriae, Listeria monocytogenes
Term
Penicilling G is not very effective against Gram (__) b/c they have outer lipopolysaccharide membrane that presents a barrier to water-soluble penicillins
Definition
-
Term
Penicillin G: Spectrum
Some Gram (-) have ____ in outer membrane that will allow some penicillins to enter
G(-) cocci – (2)
G(-) bacilli- most are _____
Definition
pores (porins)
Neisseria gonorrhoeae, N. meningitidis
resistant
Term
Penicillin G: Spectrum
Spirochetes susceptible: (1)
Definition
Treponema pallidum - syphilis
Term
Resistance through Beta-lactamases:
B-lactamases are enzymes produced by some bacteria and are responsible for their resistance to beta-lactam antibiotics. This resistance Can be ____ or ____ through transfer of plasmid
Definition
constitutive
acquired
Term
Resistance through Decreased permeability to drug:
In gram(__) -> a drug's decreased ability to cross outer membrane causes resistance
Definition
-
Term
Resistance through Altered Penicillin Binding Proteins:
Bacteria can develop and produce mutated forms of PBPs that have lower affinity for _____. Example?
Definition
penicillins
MRSA=Methicillin Resistant Staph. aureus
Term
_____ blocks tubular transporter in kidneys and elevates plasma levels of penicillin
Definition
Probenecid
Term
Adverse reactions of B-lactams:
Hypersensitivity (Allergy):
____ of penicillins serves as hapten to cause immune reactions.
About __% of patients react.
Maculopapular rash, angioedema, anaphylaxis
Cross-reactivity occurs with all ____
Definition
Metabolite
5
b-lactams
Term
Adverse reactions of B-lactams:
_____ from imbalance of GI flora
____ & ____ -> decreased agglutination of platelets
Definition
Diarrhea
Carbenicillin & ticarcillin
Term
Ampicillin is what type of drug?
Definition
Extended Spectrum Penicillins
Term
Amoxicillin is what type of drug?
Definition
Extended Spectrum Penicillins
Term
Extended Spectrum Penicillins are _____ sensitive
Definition
Penicillinase (beta-lactamase)
Term
Amoxicillin Can combine with ____ (____ inhibitor) to enhance spectrum
Definition
clavulanic acid
penicillinase
Term
Amoxicillin + clavulanic acid = ____
Definition
Augmentin
Term
Amoxicillin has _____ oral bioavailability
Definition
good
Term
Extended spectrum antibiotics affect these bacteria: (6)
Definition
Haemophilus influenzae
E. coli
Listeria monocytogenes
Proteus mirabilis
Salmonella
enterococci

HELPS kill enterococci
Term
Adverse Reactions of Extended Spectrum Antibiotics: (2)
Definition
Hypersensitivity
Pseudomembranous colitis
Term
For meningitis use ____ and do not use _____ due to resistance
Definition
ceftriaxone
benzylpenicillin
Term
Cephalosporins are Very valuable for many gram (__) infections
activity against ____
inactive against ____ & ____
Definition
-
Klebsiella
enterococci & methicillin-resistant staph.
Term
Cefazolin is what type of drug?
Definition
1st generation Cephalosporin
Term
cephalexin is what type of drug?
Definition
1st generation Cephalosporin
Term
Cefuroxime is what type of drug?
Definition
2nd generation Cephalosporin
Term
Ceftriaxone is what type of drug?
Definition
3rd generation Cephalosporin
Term
Ceftazidime is what type of drug?
Definition
4th Generation Cephalosporin
Term
___ generation Cephalosporin is effective to treat meningitis
Definition
3rd (Ceftriaxone)
Term
First generation Cephalosporins are Very active against gram (__) ____. Modestly active against gram (__) organisms. They ___ penetrate the CNS. Do no use for ____.
Definition
+
cocci
-
Do not
meningitis
Term
Second generation Cephalosporins are Moderately active against gram (__) organisms. They Have extended gram (__) coverage. They are Inactive against ____. Cefuroxime __ penetrate the CNS.
Definition
+
-
Pseudomonas aeruginosa
does
Term
Third and Fourth generation Cephalosporins are Less active against gram (__) bacteria than those of second generation.
Expanded gram (__) coverage.

They ___ penetrate the CNS.
Exceptions: _____ & ____

_____ has Adequate antipseudomonal activity
_____ has Activity against B. fragilis
Definition
+
-
do

Cefoperazone & Cefixime

Ceftazidime
Ceftizoxime
Term
1st Generation Cephalosporins:
______ ->(use IV)
______ & ______ -> (use PO)
______, _______, & _______ -> (IV,PO)
Definition
Cefazolin
cephalexin & Cefadroxil
cephalothin, cephapirin, cephradine
Term
1st Generation Cephalosporins affect Gram(+) cocci as well as... (3)
Definition
Proteus mirabilis
E. coli
Klebsiella pneumoniae
Term
____ Generation Cephalosporins are Useful in skin and soft tissue infections S. pyrogenes and/or S. aureus
Definition
1st
Term
___ Generation Cephalosporins are Useful for prophylaxis before surgery
Definition
1st
Term
________: 2nd Generation Cephalosporin that has activity against H. influenzae and is Used for community-acquired respiratory infections (otitis media, sinusitis, pneumonia)
Definition
Cefuroxime
Term
____(3)____: 2nd Generation Cephalosporin With activity against Bacteroides fragilis. Used for mixed aerobic-anaerobic infections, usually intra-abdominal, or infected lower limb of diabetic
Definition
Cefmetazole, cefotetan, cefoxitin
Term
3rd Generation Cephalosporins Have increased activity versus gram (__) bacilli, particularly ____ and _____
Definition
-
Enterobacteriaceae
H. influenzae.
Term
___ Generation Cephalosporins are the Drug of choice for N. gonorrhea
Definition
3rd (Ceftriaxone)
Term
____ Generation Cephalosporins Achieve adequate concentrations in CSF against major meningeal pathogens
Definition
3rd (Ceftriaxone)
Term
____ Generation Cephalosporins Use for meningitis & serious infections such as nosocomial pneumonia due to aerobic Gram (-) bacilli
Definition
3rd (Ceftriaxone)
Term
________ is Stable to b-lactamase
Definition
Ceftriaxone
Term
______ Generation Cephalosporins are Active against Pseudomonas aeruginosa
Definition
3rd/4th
Term
Oral extended spectrum 3rd/4th generation cephalosporins
______ & _______ are Used to treat infections due to Enterobacteriaceae resistant to other oral b-lactams. They are Less active than other 3rd/4th generations for Gram (__) bacilli & _______ & _____
Definition
Cefixime & cefpodoxime
-
P. aeruginosa & S. aureus
Term
Imipenem is what type of drug?
Definition
Carbapenems
Term
Carbapenems are a class of ____ antibiotics with a ____ spectrum of antibacterial activity.
Definition
beta-lactam
broad
Term
Carbapenems Resists hydrolysis by most _____
Definition
b-lactamases
Term
Imipenem always given with ____(an inhibitor of ____) to decrease inactivation in renal tubules
Definition
cilastatin
renal dihydropeptidase I
Term
______: Drug of choice for Enterobacter
Definition
Carbapenems (Imipenem/cilastatin)
Term
Aztreonam is a synthetic monocyclic ____ antibiotic (a ___)
Definition
beta-lactam
monobactam
Term
Aztreonam is a monobactam resistant to ____
Definition
b-lactamases
Term
Mechanism of Action of Aztreonam?
Definition
Binds to PBPs and inhibits cell wall synthesis
Term
Aztreonam is Synergistic with _____
Definition
aminoglycosides
Term
Aztreonam has No cross-reactivity with _____
Definition
penicillins
Term
Aztreonam is Used for Gram (__) ____, Klebsiella, Pseudomonas, Serratia.
Definition
-
rods
Term
Aztreonam is Not active vs. gram (__) or ____.
Definition
+
anaerobes
Term
What antibiotic is Used for penicillin-allergic patients and those with renal insufficiency who can’t tolerate aminoglycosides.?
Definition
Aztreonam
Term
Clavulanic Acid is what type of drug?
Definition
b-lactamase Inhibitor
Term
Sulbactam is what type of drug?
Definition
b-lactamase Inhibitor
Term
Tazobactam is what type of drug?
Definition
b-lactamase Inhibitor
Term
b-lactamase Inhibitors (3)...
Definition
Clavulanic Acid
Sulbactam
Tazobactam
Term
b-lactamase Inhibitors have No significant ____ activity by themselves. They Bind to and _____ b-lactamases and therefore Protect co-administered _____.
Definition
antibacterial
inactivate
antibiotic
Term
Vancomycin is a tricyclic _____ antibiotic (not a lactam)
Definition
glycopeptide
Term
MEchanism of action of Vancomycin?
Definition
Inhibits cell wall mucopeptide formation
Term
Vancomycin is bacterio______
Definition
cidal
Term
_____ is the antibiotic Used for serious gram (+) multidrug-resistant organisms including S. aureus, Clostridium difficile (pseudomembranous colitis)
Definition
Vancomycin
Term
What antibiotic has this Toxicity: nephrotoxic, ototoxicity, thrombophlebitis, diffuse flushing -> "red man
syndrome”
Definition
Vancomycin
Term
_____ is the antibiotic used to treat methicillin-resistant Staph. Infection (MRSA); ____ can also be used
Definition
Vancomycin
Cipro
Term
With Drug resistant S. pneumoniae: ______ can be used for severely ill patients.
Definition
Vancomycin
Term
For methicillin/vancomycin-resistant staph infection use ____
Definition
linezolid
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