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89 Cards in this Set
- Front
- Back
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Name three groups of beta-lactam antibiotics:
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1) Penicillins
2) Cephalosporins 3) Carbapenems |
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What are glycopeptides?
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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. |
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Name three macrolide antibiotics:
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1) Erythromycin
2) Clarithromycin 3) Azithromycin |
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Which group of antibiotics does azithromycin belong to?
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Azithromycin is a macrolide antibiotic.
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Which group of antibiotics does clarithromycin belong to?
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Clarithromycin is a macrolide antibiotic.
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Which group of antibiotics does erythromycin belong to?
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Erythromycin is a macrolide antibiotic.
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Name a commonly-used lincosamide antibiotic:
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Clindamycin
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Which group of antibiotics does clindamycin belong to?
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Clindamycin is a lincosamide antibiotic.
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What is the mechanism of action of macrolide antibiotics?
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Macrolides bind to the 50s subunit of the bacterial ribosome and inhibit bacterial protein synthesis.
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What is the mechanism of action of lincosamide antibiotics?
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Lincosamides such as clindamycin bind to the 50s subunit of the bacterial ribosome and inhibit bacterial protein synthesis.
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What is the mechanism of action of aminoglycoside antibiotics?
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The aminoglycosides, such as gentamicin, bind to the 30s subunit of the bacterial ribosome, thereby inhibiting protein synthesis.
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What's the difference between glycopeptides, peptidoglycans, and aminoglycoside?
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Glycopeptide
-group of cell wall synthesis inhibitors that includes vancomycin Peptidoglycan -polymer that comprises the bacterial cell wall Aminoglycoside -group of protein synthesis inhibitors |
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Name three aminoglycoside antibiotics:
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Gentamicin
Tobramicin Streptomycin |
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Which group of antibiotics does gentamicin belong to?
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Gentamicin is an aminoglycoside antibiotic.
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Which group of antibiotics does tobramycin belong to?
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Tobramycin is an aminoglycoside antibiotic.
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Which group of antibiotics does streptomycin belong to?
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Streptomycin is an aminoglycoside antibiotic.
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What environmental requirement is aminoglycoside efficacy dependant on? Why?
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Aminoglycosides need an aerobic environment to function because their uptake into bacterial cells occurs via an oxygen and energy-dependant process.
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Name two streptogramin antibiotics:
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Quinupristin
Dalfopristin Available in combination as quinupristin/dalfopristin. |
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What is the mechanism of action of streptogramin antibiotics?
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The streptogramins (quinupristin/dalfopristin) are protein synthesis inhibitors, binding at various points the bacterial ribosome to accomplish the feat.
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Which group of antibiotics does quinupristin/dalfopristin belong to?
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Quinupristin and dalfopristin are streptogramin antibiotics.
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Name two tetracycline antibiotics:
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Tetracycline
Doxycycline |
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What is the mechanism of action of the tetracyclines?
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The tetracyclines bind to the 30s ribosomal subunit and inhibit bacterial protein synthesis.
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Which group of antibiotics does tetracycline belong to?
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Tetracycline is a tetracycline protein synthesis inhibitor.
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Which group of antibiotics does doxycycline belong to?
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Doxycycline is a tetracycline protein synthesis inhibitor.
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What is the mechanism of action of chloramphenicol?
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Chloramphenicol binds to the 50s subunit of the bacterial ribosome and inhibits protein synthesis.
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What is the mechanism of action of linezolid?
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Linezolid binds to the 50s subunit of the bacterial ribosome, inhibiting protein synthesis
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Name 6 groups of protein synthesis-inhibting antibiotics:
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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 |
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Which 5 questions should a physician be able to answer about a specific antibiotic before prescribing it?
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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? |
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How are aminoglycosides cleared from the body?
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Aminoglycosides are cleared renally and can damage the kidney.
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Name two serious adverse effects of aminoglycoside therapy:
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1) Vestibulocochlear nerve (CN VIII) toxicity
-results in irreversible hearing loss and vertigo 2) Kidney toxicity -can induce renal failure, follow BUN and creatinine |
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Which group of antibiotics does amikacin belong to?
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Amikacin is an aminoglycoside antibiotic.
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What bloodwork should be monitored durining aminoglycoside therapy?
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Kidney: BUN/creatinine
Serum aminoglycoside levels should also be monitored once steady state has been achieved. |
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What is the clinical indication for quinupristin/dalfopristin?
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Infection with vancomycin-resistant enterococci, specifically E. faecium and NOT E. faecalis
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What are the adverse effects of quinupristin/dalfopristin?
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This is a nasty drug that causes hyperbilirubinemia and myalgias/arthralgias.
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What is the main clinical indication for aminoglycoside therapy?
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Treatment of the gram-negative enterics plus pseudomonas infection.
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Describe the spectrum of chloramphenicol:
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Chloramphenicol has a very wide spectrum and kills most clinically-important Gram-positives, Gram-negatives, and anaerobes.
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What rare but severe adverse effect of chloramphenicol causes this otherwise-excellent antibiotic to be used only when no other option is available?
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Chloramphenicol can cause bone marrow depression and fatal irreversible aplastic anemia.
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Which antibiotic can cause fatal aplastic anemia?
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Chloramphenicol, though this adverse effect is very rare.
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What is the principle clinical use of clindamycin?
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Clindamycin, a lincosamide antibiotic, covers anaerobic bacteria, including Bacteroides fragilis.
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Name a common adverse effect to clindamycin therapy:
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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. |
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What's the biggest downside to linezolid therapy?
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Linezolid is extremely expensive.
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Why is aminoglycoside therapy often combined with penicllin therapy?
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Aminoglycoside must cross the cell wall to begin working. Penicllins break down this cell wall, allowing aminoglycosides to do their job better.
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What is the principal clinical use of aminoglycosides?
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Infection with Gram-negative enterics.
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What does armamentarium mean?
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An armamentarium is the aggregate of equipment, methods, and techniques available to one for carrying out one's duties.
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Why should bacteriostatic antibiotics not be combined with beta-lactam antibiotics?
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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.
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What is penicillin V?
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Penicillin V is phenoxymehtylpenicillin.
This is an orally active version of penicillin. |
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What does the G stand for in penicillin G?
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The G is for gold standard.
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Which genus of fungi gives us the natural penicillins?
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Penicillium
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Who discovered penicillin and when?
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Alexander Fleming discovered penicillin in 1928.
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What are the aminopenicillins?
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The aminopenicillins are ampicillin and amoxicillin.
They are also available in combination with with beta-lactamase inhibitors as: 1) Amoxicillin-clavulanate 2) Ampicillin-sulbactam |
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Name the beta-lactamase inhibitor that is often combined with amoxicillin.
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Clavulanate
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Name the beta-lactamase inhibitor used in conjunction with ampicillin.
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Sulbactam
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What is ampicillin meant to cover in the common antibiotic combination "amp-gent"?
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Aminopenicillins (ampicillin and amoxicillin) are some of the few drugs effective against Gram-positive enterococci.
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What is the clinical indication for the penicillinase-resistant penicillins?
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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. |
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Name 4 penicillinase-resistant penicllins.
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Nafcillin
Oxacillin Cloxacillin Methicillin |
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What does PCN stand for?
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Penicillin
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What are the four main classes of penicillins in order from narrowest to broadest spectrum?
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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 |
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Which class of antibiotics is first line against MSSA?
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First-line treatment against MSSA include the penicillinase-resistant PCNs.
-methicillin (now discontinued) -nafcillin -oxacillin -cloxacillin/dicloxacillin |
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Which are the so-called anti-pseudomonal penicillins (PCNs)?
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The antipseudomonal penicillins are also called the carboxy/ureidopenicillins.
They include: -piperacillin-tazobactam -ticaracillin-tazobactam |
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Describe the spectrum of the natural penicillins.
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The natural penicillins have a very narrow spectrum, being used mostly for streptococcal infections.
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Describe the spectrum of the penicillinase-resistant penicillins.
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The penicillinase-resistant penicillins, like the natural penicillins, have a very narrow spectrum. They are used for to treat MSSA infections.
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Describe the spectrum of the aminopenicillins.
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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).
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Describe the spectrum of the carboxy/ureido aminopenicillins.
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These antibiotics have a very wide spectrum that includes streptococi, E. faecalis, gram-negative enterics, pseudomonas, and some anaerobic bacteria.
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Does ertapenem cover Pseudomonas?
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No.
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Does meropenem cover Pseudomonas?
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Yes!
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Does imipenem cover Pseudomonas?
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Yes!
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Which of the carbapenem antibiotics cover Pseudomonas and which do not?
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Meropenem and imipenem cover Pseudomonas, ertapenem does not.
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What is Keflex?
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Kelfex is the trade name for cephalexin, a first generation cephalosporin.
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What is Ancef?
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Ancef is the trade name for cefazolin, a first generation cephalosporin.
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What is Flagyl?
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Flagyl is the trade name for metronidazole.
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What is Clavulin?
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Clavulin is the trade name for amoxicillin-clavulanic acid.
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Where do cephalosporins get their name?
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Cephalosporins were originally derived from the fungus Acremonium, which used to be called Cephalosporium.
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What natural organism were cephalosporins originally derived from?
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The cephalosporins were originally derived from fungi of the genus Acremonium, previously known as Cephalosporium.
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What is the natural source of the carbapenems?
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The carbapenem antibiotics were originally derived from bacteria of the genus Streptomyces.
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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) |
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Describe the spectrum of coverage of the first generation cephalosporins.
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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. |
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Jumping from first to second generation cephalosporin adds what coverage at the expense of what? Be specific.
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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. |
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Name 2 first-generation cephalosporins.
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Cefazolin (Ancef)
Cephalexin (Keflex) |
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What is the trade name for cefazolin?
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Ancef
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What is the trade name of cephalexin?
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Keflex
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What is the trade name for metronidazole?
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Flagyl
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What is the trade name for amoxicillin-clavulanate?
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Clavulin
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What is the natural source of clavulanic acid?
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Streptomyces clavuligerus, a bacterium.
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What is the significance of the bacteria species Streptomyces clavuligerus?
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Streptomyces clavuligerus is the natural source of clavulanic acid.
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Which two genera of Gram-positive bacteria are not covered by any cephalosporin?
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Enterococcus
Listeria |
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Name 3 second-generation cephalosporins
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Cefuroxime (actually a cephalosporin)
Cefotetan (actually a cephomycin) Cefoxitin (actually a cephomycin) |
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Which class of antibiotics do cefoxitin and cefotetan belong to?
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Strictly speaking these are cephamycin antibiotics but they are often grouped with the second-generation cephalosporin.
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Name a cephalosporin that covers Pseudomonas.
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Ceftazidime, a third-generation cephalosporin.
Cefotazime and Ceftriaxone do not cover Pseudomonas. |
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Name 3 third-generation cephalosporins.
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Ceftazidime
-covers pseudomonas Ceftriaxone -no Pseudomonas coverage Cefotaxime -no Pseudomonas coverage |
