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Questions and Answers
How does vancomycin elicit its bactericidal effects?
How does vancomycin elicit its bactericidal effects?
- By disrupting the bacterial cell membrane integrity, leading to leakage of cellular contents.
- By inhibiting bacterial DNA gyrase, preventing DNA replication and bacterial multiplication.
- By directly binding to the D-Ala-D-Ala portion of the peptidoglycan precursor, preventing cell wall synthesis. (correct)
- By irreversibly binding to the 30S ribosomal subunit, inhibiting protein synthesis.
Which of the following scenarios would warrant the oral administration of vancomycin?
Which of the following scenarios would warrant the oral administration of vancomycin?
- Treatment of a bloodstream infection caused by methicillin-resistant _Staphylococcus aureus_ (MRSA).
- Treatment of a severe skin and soft tissue infection (SSTI) caused by _Streptococcus pyogenes_.
- Treatment of _Clostridium difficile_ infection. (correct)
- Empiric therapy for a suspected case of bacterial meningitis.
Which property is unique to lipoglycopeptides, such as dalbavancin and oritavancin, when compared to vancomycin?
Which property is unique to lipoglycopeptides, such as dalbavancin and oritavancin, when compared to vancomycin?
- Increased risk of nephrotoxicity.
- Activity against vancomycin-resistant _Enterococcus_ (VRE).
- No activity against _Clostridium difficile_ infections. (correct)
- Effective against _Clostridium difficile_ infections.
What is the primary reason daptomycin is not used in the treatment of pneumonia?
What is the primary reason daptomycin is not used in the treatment of pneumonia?
A patient is receiving vancomycin for a MRSA infection and reports flushing, erythema, and pruritus during the infusion. Which of the following is the MOST appropriate intervention?
A patient is receiving vancomycin for a MRSA infection and reports flushing, erythema, and pruritus during the infusion. Which of the following is the MOST appropriate intervention?
Which of the following drug combinations would MOST significantly increase the risk of myopathy or rhabdomyolysis?
Which of the following drug combinations would MOST significantly increase the risk of myopathy or rhabdomyolysis?
Which of the following antibiotics is MOST likely to cause nephrotoxicity when used concomitantly with tacrolimus?
Which of the following antibiotics is MOST likely to cause nephrotoxicity when used concomitantly with tacrolimus?
A patient with a severe penicillin allergy requires treatment for a gram-positive infection. Which of the following antibiotics would be the MOST appropriate choice, assuming susceptibility?
A patient with a severe penicillin allergy requires treatment for a gram-positive infection. Which of the following antibiotics would be the MOST appropriate choice, assuming susceptibility?
Which of the following antibiotics is effective against a broad range of gram-negative bacteria, including Pseudomonas aeruginosa and Escherichia coli?
Which of the following antibiotics is effective against a broad range of gram-negative bacteria, including Pseudomonas aeruginosa and Escherichia coli?
A pregnant patient is diagnosed with a complicated skin and soft tissue infection (SSTI) caused by MRSA. Which of the following antibiotics should be avoided due to contraindications in pregnancy?
A pregnant patient is diagnosed with a complicated skin and soft tissue infection (SSTI) caused by MRSA. Which of the following antibiotics should be avoided due to contraindications in pregnancy?
Flashcards
Vancomycin
Vancomycin
Bactericidal glycopeptide that blocks cell wall glycosyltransferases by binding to the D-Ala-D-Ala stem peptide terminus.
Lipoglycopeptides
Lipoglycopeptides
Gram-positive coverage (MSSA, MRSA, enterococcus) but also covers Clostridium difficile infections.
Daptomycin
Daptomycin
Activity includes Gram-positive coverage plus vancomycin-resistant enterococcus (VRE).
Polymyxin B
Polymyxin B
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Red-Person Syndrome
Red-Person Syndrome
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Myopathy/Rhabdomyolysis
Myopathy/Rhabdomyolysis
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Nephrotoxicity
Nephrotoxicity
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Ototoxicity
Ototoxicity
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Study Notes
- Glycopeptides are bactericidal.
- Resistance is caused by an altered D-Ala-D-Ala target.
- Beta-lactams block cell wall glycosyltransferases by binding to the D-Ala-D-Ala stem peptide terminus.
Vancomycin
- Vancomycin's spectrum of activity covers extensive gram-positive bacteria, including MSSA, MRSA, and enterococcus.
- It is effective against Clostridium difficile, but has no gram-negative and virtually no anaerobic coverage.
- Side effects include red-person syndrome, nephrotoxicity, ototoxicity, thrombophlebitis, and infusion-related flushing, causing hypotension, erythema, and pruritus..
- Risk of nephrotoxicity increases when used with amphotericin B, loop diuretics, tacrolimus, cyclosporine, cisplatin, or other nephrotoxic agents.
- Vancomycin's bactericidal effect is time-dependent and often used for penicillin-allergic patients.
- Administer orally, not intravenously, to treat C. difficile.
- Oral vancomycin is ineffective for other infections.
- Reduce the infusion rate if red-man syndrome occurs.
- Vancomycin is not susceptible to beta-lactamase enzymes.
Lipoglycopeptides
- Lipoglycopeptides include dalbavancin, oritavancin, and telavancin.
- Their spectrum includes extensive gram-positive coverage (MSSA, MRSA, enterococcus, etc.).
- They have no gram-negative coverage, virtually no anaerobic coverage, and do not treat Clostridium difficile infections.
- These are contraindicated in pregnancy.
- Side effects include myopathy/rhabdomyolysis and peripheral neuropathy.
- Using lipoglycopeptides with statins may increase myopathy; discontinuing statin therapy should be considered.
- Lipoglycopeptides are indicated for complicated SSTIs and staph aureus bloodstream infections.
Cyclic Lipopeptide: Daptomycin
- Daptomycin covers extensive gram-positive bacteria, including MSSA, MRSA, and enterococcus.
- It is effective against Clostridium difficile (PO) and vancomycin-resistant enterococcus (VRE).
- It has no gram-negative and virtually no anaerobic coverage.
- Daptomycin is not used to treat pneumonia, as the drug is inactivated by surfactant.
- Side effects include myopathy/rhabdomyolysis and peripheral neuropathy.
- Concomitant use of statins may increase the risk of myopathy; discontinuing statin therapy should be considered.
- Daptomycin can result in rhabdomyolysis in patients also taking statin therapy and increase bleeding risk.
- It is indicated for complicated SSTIs and staph aureus bloodstream infections.
Cyclic Lipopeptide: Polymyxin B
- Polymyxin B covers extensive gram-negative bacilli, including non-BLP and BLP E. coli, Klebsiella, H. influenzae, SPACE, ESBL, and Pseudomonas.
- It has no gram-positive and no anaerobic coverage.
- It is contraindicated with nephro- and neurotoxic agents.
- Side effects include nephrotoxicity, neurotoxicity, and respiratory failure.
- Polymyxin B can treat multidrug-resistant gram-negative bacteria like P. aeruginosa, E. coli, and K. pneumoniae.
- It may potentiate neuromuscular blockade with aminoglycosides and curariform muscle relaxants.
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