Podcast
Questions and Answers
What is the primary mechanism of action of beta-lactam antibiotics?
What is the primary mechanism of action of beta-lactam antibiotics?
- Inhibiting DNA replication
- Binding to penicillin-binding proteins and inhibiting cell wall crosslinking (correct)
- Disrupting the cytoplasmic membrane
- Inhibiting protein synthesis
What is a common side effect of beta-lactam antibiotics?
What is a common side effect of beta-lactam antibiotics?
- Hypercalcemia
- Hypernatremia
- Hypokalemia
- Hypersensitivity reactions (correct)
Which of the following beta-lactam antibiotics has activity against MRSA?
Which of the following beta-lactam antibiotics has activity against MRSA?
- Amoxicillin
- Cefepime
- Piperacillin/Tazobactam
- Ceftaroline (correct)
Why are oral beta-lactams often poor choices for serious or deep-seated infections?
Why are oral beta-lactams often poor choices for serious or deep-seated infections?
What is the characteristic of beta-lactam antibiotics in terms of their killing mechanism?
What is the characteristic of beta-lactam antibiotics in terms of their killing mechanism?
What is the name of the group of organisms that have inducible, chromosomal beta-lactamases and may lead to resistance to beta-lactams?
What is the name of the group of organisms that have inducible, chromosomal beta-lactamases and may lead to resistance to beta-lactams?
Which of the following beta-lactam antibiotics is not affected by the inducible, chromosomal beta-lactamases of the SPICE-A organisms?
Which of the following beta-lactam antibiotics is not affected by the inducible, chromosomal beta-lactamases of the SPICE-A organisms?
Why are beta-lactam antibiotics preferred in many situations?
Why are beta-lactam antibiotics preferred in many situations?
What is the main reason why beta-lactams are not effective against atypical intracellular organisms?
What is the main reason why beta-lactams are not effective against atypical intracellular organisms?
What type of infections is Penicillin G or V commonly used to treat?
What type of infections is Penicillin G or V commonly used to treat?
Which of the following bacteria is universally sensitive to Penicillin?
Which of the following bacteria is universally sensitive to Penicillin?
What is the primary indication for using Penicillin G or V in pregnant women?
What is the primary indication for using Penicillin G or V in pregnant women?
Which of the following is NOT a typical spectrum of activity for Penicillin G or V?
Which of the following is NOT a typical spectrum of activity for Penicillin G or V?
What type of infections may require desensitization to Penicillin in some cases?
What type of infections may require desensitization to Penicillin in some cases?
Flashcards are hidden until you start studying
Study Notes
Beta-Lactams
- Beta-lactams include PCNs, Cephalosporins, Carbapenems, and Monobactam (Aztreonam)
- They inhibit cell wall crosslinking by binding to Penicillin-binding proteins (PBPs) in the cell membrane, making them bactericidal
Side Effects
- Hypersensitivity reactions, including anaphylaxis
- Rashes
- Bone marrow suppression
- Interstitial Nephritis
- GI symptoms: nausea, diarrhea, and C. diff
- Seizures (mainly with high doses in renal failure)
Preferred Use
- Beta-lactams are the preferred drug choice for most situations due to high efficacy and cidal nature, as long as the pathogen is susceptible and the patient is not allergic
Pharmacokinetics
- Most oral beta-lactams have poor bioavailability and achieve low serum concentrations, making them poor choices for serious or deep-seated infections
- Amoxicillin has the best bioavailability among oral beta-lactams
Limitations
- No beta-lactam has activity against MRSA, except Ceftaroline
- No beta-lactam has activity against atypical intracellular organisms (e.g., Legionella, Mycoplasma, Chlamydia)
Pharmacodynamics
- Beta-lactams exhibit time-dependent killing, meaning efficacy depends on the amount of time the drug concentration is above the MIC
Inducible Resistance
- SPICE-A organisms (Serratia, Pseudomonas/Providencia, Indole-positive Proteus, Citrobacter, Enterobacter, and Acinetobacter) have inducible, chromosomal beta-lactamases (AmpC) that may not be detected on initial susceptibility testing
- These beta-lactamases can lead to resistance while on therapy to all beta-lactams except carbapenems
- Cefepime and Piperacillin/Tazobactam can be used with caution as well
Penicillins
- Penicillin G is administered intravenously (IV), while Penicillin V is administered orally (PO)
Spectrum of Activity
- Effective against many strains of Streptococci, including Group A Strep (universally PCN sensitive)
- Effective against a minority of Staphylococci (most are resistant)
- Effective against some Enterococcus and most oral anaerobes
- Effective against Syphilis (universally PCN sensitive)
Indications
- Treats Strep throat and other infections caused by Group A Strep
- Treats Syphilis (must desensitize to PCN for neurosyphilis or pregnant women)
- Treats bacteremia and endocarditis caused by PCN sensitive Streptococcus, Enterococcus, or Staph aureus
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
