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89 Cards in this Set

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Name three groups of beta-lactam antibiotics:
1) Penicillins
2) Cephalosporins
3) Carbapenems
What are glycopeptides?
The glycopeptides are a group of cell wall synthesis-inhibting antibiotics that include vancomycin.

Don't confuse glycopeptides with peptidoglycan, the polymer that forms the bacterial cell wall.
Name three macrolide antibiotics:
1) Erythromycin
2) Clarithromycin
3) Azithromycin
Which group of antibiotics does azithromycin belong to?
Azithromycin is a macrolide antibiotic.
Which group of antibiotics does clarithromycin belong to?
Clarithromycin is a macrolide antibiotic.
Which group of antibiotics does erythromycin belong to?
Erythromycin is a macrolide antibiotic.
Name a commonly-used lincosamide antibiotic:
Clindamycin
Which group of antibiotics does clindamycin belong to?
Clindamycin is a lincosamide antibiotic.
What is the mechanism of action of macrolide antibiotics?
Macrolides bind to the 50s subunit of the bacterial ribosome and inhibit bacterial protein synthesis.
What is the mechanism of action of lincosamide antibiotics?
Lincosamides such as clindamycin bind to the 50s subunit of the bacterial ribosome and inhibit bacterial protein synthesis.
What is the mechanism of action of aminoglycoside antibiotics?
The aminoglycosides, such as gentamicin, bind to the 30s subunit of the bacterial ribosome, thereby inhibiting protein synthesis.
What's the difference between glycopeptides, peptidoglycans, and aminoglycoside?
Glycopeptide
-group of cell wall synthesis inhibitors that includes vancomycin

Peptidoglycan
-polymer that comprises the bacterial cell wall

Aminoglycoside
-group of protein synthesis inhibitors
Name three aminoglycoside antibiotics:
Gentamicin
Tobramicin
Streptomycin
Which group of antibiotics does gentamicin belong to?
Gentamicin is an aminoglycoside antibiotic.
Which group of antibiotics does tobramycin belong to?
Tobramycin is an aminoglycoside antibiotic.
Which group of antibiotics does streptomycin belong to?
Streptomycin is an aminoglycoside antibiotic.
What environmental requirement is aminoglycoside efficacy dependant on? Why?
Aminoglycosides need an aerobic environment to function because their uptake into bacterial cells occurs via an oxygen and energy-dependant process.
Name two streptogramin antibiotics:
Quinupristin
Dalfopristin

Available in combination as quinupristin/dalfopristin.
What is the mechanism of action of streptogramin antibiotics?
The streptogramins (quinupristin/dalfopristin) are protein synthesis inhibitors, binding at various points the bacterial ribosome to accomplish the feat.
Which group of antibiotics does quinupristin/dalfopristin belong to?
Quinupristin and dalfopristin are streptogramin antibiotics.
Name two tetracycline antibiotics:
Tetracycline
Doxycycline
What is the mechanism of action of the tetracyclines?
The tetracyclines bind to the 30s ribosomal subunit and inhibit bacterial protein synthesis.
Which group of antibiotics does tetracycline belong to?
Tetracycline is a tetracycline protein synthesis inhibitor.
Which group of antibiotics does doxycycline belong to?
Doxycycline is a tetracycline protein synthesis inhibitor.
What is the mechanism of action of chloramphenicol?
Chloramphenicol binds to the 50s subunit of the bacterial ribosome and inhibits protein synthesis.
What is the mechanism of action of linezolid?
Linezolid binds to the 50s subunit of the bacterial ribosome, inhibiting protein synthesis
Name 6 groups of protein synthesis-inhibting antibiotics:
1) Aminoglycosides
-gentamicin, tobramicin, streptomycin

2) Macrolides
-erythromycin, clarithromycin, azithromycin

3) Lincosamides
-clindamycine

4) Tetracyclines
-tetracycline, doxycycline

5) Streptogramins
-quinupristin/dalfopristin

5) Chloramphenicol

6) Linezolid
Which 5 questions should a physician be able to answer about a specific antibiotic before prescribing it?
1) How does this antibiotic work?

2) What are the potential toxicities and should they be monitored?

3) How is the drug metabolized? Does a dosing schedule need to be modified in patients with renal dysfunction?

4) How broad is the spectrum?

5) How much does this drug cost?
How are aminoglycosides cleared from the body?
Aminoglycosides are cleared renally and can damage the kidney.
Name two serious adverse effects of aminoglycoside therapy:
1) Vestibulocochlear nerve (CN VIII) toxicity
-results in irreversible hearing loss and vertigo

2) Kidney toxicity
-can induce renal failure, follow BUN and creatinine
Which group of antibiotics does amikacin belong to?
Amikacin is an aminoglycoside antibiotic.
What bloodwork should be monitored durining aminoglycoside therapy?
Kidney: BUN/creatinine

Serum aminoglycoside levels should also be monitored once steady state has been achieved.
What is the clinical indication for quinupristin/dalfopristin?
Infection with vancomycin-resistant enterococci, specifically E. faecium and NOT E. faecalis
What are the adverse effects of quinupristin/dalfopristin?
This is a nasty drug that causes hyperbilirubinemia and myalgias/arthralgias.
What is the main clinical indication for aminoglycoside therapy?
Treatment of the gram-negative enterics plus pseudomonas infection.
Describe the spectrum of chloramphenicol:
Chloramphenicol has a very wide spectrum and kills most clinically-important Gram-positives, Gram-negatives, and anaerobes.
What rare but severe adverse effect of chloramphenicol causes this otherwise-excellent antibiotic to be used only when no other option is available?
Chloramphenicol can cause bone marrow depression and fatal irreversible aplastic anemia.
Which antibiotic can cause fatal aplastic anemia?
Chloramphenicol, though this adverse effect is very rare.
What is the principle clinical use of clindamycin?
Clindamycin, a lincosamide antibiotic, covers anaerobic bacteria, including Bacteroides fragilis.
Name a common adverse effect to clindamycin therapy:
Pseudomembranous colitis.

Clindamycin is a potent antibiotic against gut flora and can clear the way for C. dificile overrun.

To treat C. dificile use metronidazole or oral vancomycin.
What's the biggest downside to linezolid therapy?
Linezolid is extremely expensive.
Why is aminoglycoside therapy often combined with penicllin therapy?
Aminoglycoside must cross the cell wall to begin working. Penicllins break down this cell wall, allowing aminoglycosides to do their job better.
What is the principal clinical use of aminoglycosides?
Infection with Gram-negative enterics.
What does armamentarium mean?
An armamentarium is the aggregate of equipment, methods, and techniques available to one for carrying out one's duties.
Why should bacteriostatic antibiotics not be combined with beta-lactam antibiotics?
The activity of all beta-lactam antibiotics requires active bacterial growth and active cell wall synthesis. Therefore, bacteria in a dormant or static phase will not be killed, but those in an active log phase of growth are quickly lysed.
What is penicillin V?
Penicillin V is phenoxymehtylpenicillin.

This is an orally active version of penicillin.
What does the G stand for in penicillin G?
The G is for gold standard.
Which genus of fungi gives us the natural penicillins?
Penicillium
Who discovered penicillin and when?
Alexander Fleming discovered penicillin in 1928.
What are the aminopenicillins?
The aminopenicillins are ampicillin and amoxicillin.

They are also available in combination with with beta-lactamase inhibitors as:

1) Amoxicillin-clavulanate
2) Ampicillin-sulbactam
Name the beta-lactamase inhibitor that is often combined with amoxicillin.
Clavulanate
Name the beta-lactamase inhibitor used in conjunction with ampicillin.
Sulbactam
What is ampicillin meant to cover in the common antibiotic combination "amp-gent"?
Aminopenicillins (ampicillin and amoxicillin) are some of the few drugs effective against Gram-positive enterococci.
What is the clinical indication for the penicillinase-resistant penicillins?
These PCNs are used against MSSA.

The natural penicillins do not cover S. aureus. The penicillinase-resistants cover MSSA. From here you're dealing with MRSA and move to vancomycin.
Name 4 penicillinase-resistant penicllins.
Nafcillin
Oxacillin
Cloxacillin
Methicillin
What does PCN stand for?
Penicillin
What are the four main classes of penicillins in order from narrowest to broadest spectrum?
1) Natural penicillins
-indicated for streptococcal infections
-Penicillin G
-Penicillin V

2) Penicillinase-resistant penicillins
-these do not hava broader spectrum than the natural penicillins but cover organisms RESISTANT to penicillin due to the development of penicillinase
-indicated for streptococcal and MSSA infections
-methicillin (no longer available)
-nafcillin
-oxacillin
-cloxacillin

3) Aminopenicillins
-spectrum broadened to include E. faecalis and some Gram-negative (selective enterics, H. influenzae)
-ampicillin
-ampicillin-sulbactrum
-amoxicillin

4) Carboxy/ureidopenicillins, also known as the anti-pseudomonal penicillins
-Strep, E. faecalis, Gram-negative enterics, Pseudomonas
Which class of antibiotics is first line against MSSA?
First-line treatment against MSSA include the penicillinase-resistant PCNs.

-methicillin (now discontinued)
-nafcillin
-oxacillin
-cloxacillin/dicloxacillin
Which are the so-called anti-pseudomonal penicillins (PCNs)?
The antipseudomonal penicillins are also called the carboxy/ureidopenicillins.

They include:
-piperacillin-tazobactam
-ticaracillin-tazobactam
Describe the spectrum of the natural penicillins.
The natural penicillins have a very narrow spectrum, being used mostly for streptococcal infections.
Describe the spectrum of the penicillinase-resistant penicillins.
The penicillinase-resistant penicillins, like the natural penicillins, have a very narrow spectrum. They are used for to treat MSSA infections.
Describe the spectrum of the aminopenicillins.
The aminopenicillins have a broader spectrum than the natural penicillins. In addition to streptococci they cover some enterococci (E. faecalis only) and some gram-negatives (enterics and H. influenzae).
Describe the spectrum of the carboxy/ureido aminopenicillins.
These antibiotics have a very wide spectrum that includes streptococi, E. faecalis, gram-negative enterics, pseudomonas, and some anaerobic bacteria.
Does ertapenem cover Pseudomonas?
No.
Does meropenem cover Pseudomonas?
Yes!
Does imipenem cover Pseudomonas?
Yes!
Which of the carbapenem antibiotics cover Pseudomonas and which do not?
Meropenem and imipenem cover Pseudomonas, ertapenem does not.
What is Keflex?
Kelfex is the trade name for cephalexin, a first generation cephalosporin.
What is Ancef?
Ancef is the trade name for cefazolin, a first generation cephalosporin.
What is Flagyl?
Flagyl is the trade name for metronidazole.
What is Clavulin?
Clavulin is the trade name for amoxicillin-clavulanic acid.
Where do cephalosporins get their name?
Cephalosporins were originally derived from the fungus Acremonium, which used to be called Cephalosporium.
What natural organism were cephalosporins originally derived from?
The cephalosporins were originally derived from fungi of the genus Acremonium, previously known as Cephalosporium.
What is the natural source of the carbapenems?
The carbapenem antibiotics were originally derived from bacteria of the genus Streptomyces.
State the natural source for each of the following classes of beta-lactam antibiotics:

1) Penicillins

2) Cephalosporins

3) Carbapenems
1) Penicillins
-Penicillium (fungi)

2) Cephalosporins
-Acremonium, formerly Cephalosporium (fungi)

3) Carbapenems
-Streptomyces (bacteria)
Describe the spectrum of coverage of the first generation cephalosporins.
The first-generation cephalosporins cover mainly Gram-positives:

1) Streptococci
2) Staphylococci --> not MRSA

Some Gram-negative coverage:
-E. coli/Klebsiella/Proteus

Note that first-gen. cephalosporins do not cover H. influenza, anaerobes, or Pseudomonas.
Jumping from first to second generation cephalosporin adds what coverage at the expense of what? Be specific.
Second generation cephalosporins are less effective against streptococci and staphylococci and more effective against Gram-negatives and anaerobes.

There is variation between the specific different second-generation cephalosporins in terms of coverage.
Name 2 first-generation cephalosporins.
Cefazolin (Ancef)

Cephalexin (Keflex)
What is the trade name for cefazolin?
Ancef
What is the trade name of cephalexin?
Keflex
What is the trade name for metronidazole?
Flagyl
What is the trade name for amoxicillin-clavulanate?
Clavulin
What is the natural source of clavulanic acid?
Streptomyces clavuligerus, a bacterium.
What is the significance of the bacteria species Streptomyces clavuligerus?
Streptomyces clavuligerus is the natural source of clavulanic acid.
Which two genera of Gram-positive bacteria are not covered by any cephalosporin?
Enterococcus
Listeria
Name 3 second-generation cephalosporins
Cefuroxime (actually a cephalosporin)
Cefotetan (actually a cephomycin)
Cefoxitin (actually a cephomycin)
Which class of antibiotics do cefoxitin and cefotetan belong to?
Strictly speaking these are cephamycin antibiotics but they are often grouped with the second-generation cephalosporin.
Name a cephalosporin that covers Pseudomonas.
Ceftazidime, a third-generation cephalosporin.

Cefotazime and Ceftriaxone do not cover Pseudomonas.
Name 3 third-generation cephalosporins.
Ceftazidime
-covers pseudomonas

Ceftriaxone
-no Pseudomonas coverage

Cefotaxime
-no Pseudomonas coverage