Macrolides in Antibiotics
24 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is one of the mechanisms of aminoglycoside resistance that involves modification of the drug?

  • Mutation of the bacterial ribosome
  • Increased accumulation within the bacterium
  • Presence of efflux pumps
  • Bacterial enzymes such as acetyltransferases (correct)

    • What is the purpose of Neomycin* when given orally?

  • To treat bacterial infections in the gut
  • To prevent bacterial infections in the skin
  • For bowel decontamination (correct)
  • To treat bacterial infections in the blood

    • Which of the following mechanisms of aminoglycoside resistance does not involve modification of the bacterium?

  • Decreased accumulation within the bacterium
  • Mutation of the bacterial ribosome
  • Bacterial enzymes such as acetyltransferases
  • Presence of efflux pumps (correct)

    • What is the general term for the enzymes that modify aminoglycosides and prevent them from binding to ribosomes?

    <p>Acetyltransferases</p> Signup and view all the answers

    What is the result of decreased accumulation within the bacterium?

    <p>Aminoglycoside resistance due to the presence of efflux pumps</p> Signup and view all the answers

    What is the mechanism of aminoglycoside resistance that involves a change in the bacterial ribosome?

    <p>Mutation of the bacterial ribosome</p> Signup and view all the answers

    What is the name of the aminoglycoside shown in Figure 6-2?

    <p>Amikacin</p> Signup and view all the answers

    Which of the following is NOT a mechanism of aminoglycoside resistance?

    <p>Inhibition of bacterial protein synthesis</p> Signup and view all the answers

    What is the main mechanism of action of macrolides?

    <p>Blocking the exit of the newly synthesized peptide from the 50S ribosome</p> Signup and view all the answers

    How do macrolides function in a manner similar to aminoglycosides?

    <p>By targeting the bacterial ribosome and preventing protein production</p> Signup and view all the answers

    What is the location of the macrolide binding site on the bacterial ribosome?

    <p>The 50S subunit</p> Signup and view all the answers

    What is the result of methylation of the ribosome binding site in some bacteria?

    <p>Impaired accumulation of macrolides within the bacterium</p> Signup and view all the answers

    What is the effect of the mef gene on macrolide accumulation in some gram-positive bacteria?

    <p>It decreases macrolide accumulation</p> Signup and view all the answers

    What is a common mechanism of resistance to macrolides in some bacteria?

    <p>Inhibition of drug entry and accumulation</p> Signup and view all the answers

    What is the result of resistance to one member of the macrolide group?

    <p>Resistance to all members of the macrolide group</p> Signup and view all the answers

    What is the structural feature of macrolides that gives them their name?

    <p>A large cyclic core called a macrocyclic lactone ring</p> Signup and view all the answers

    What is the mechanism of action of efflux pumps in bacterial resistance to aminoglycosides?

    <p>Prevention of accumulation of the aminoglycoside in the cytosol of the bacterium</p> Signup and view all the answers

    Which of the following is a mechanism of bacterial resistance to aminoglycosides that involves changes to the ribosome?

    <p>Mutations within the ribosome</p> Signup and view all the answers

    What is the target of aminoglycoside binding in bacterial cells?

    <p>Ribosome</p> Signup and view all the answers

    Which of the following is NOT a mechanism of bacterial resistance to aminoglycosides?

    <p>Inhibition of protein synthesis</p> Signup and view all the answers

    What is the result of modification of the aminoglycoside in bacterial resistance?

    <p>Reduced binding of the aminoglycoside to the ribosome</p> Signup and view all the answers

    Which mechanism of bacterial resistance to aminoglycosides involves the pumping of the antibiotic out of the cell?

    <p>Efflux pumps</p> Signup and view all the answers

    What is the site of action of aminoglycosides in bacterial cells?

    <p>30S subunit</p> Signup and view all the answers

    Which of the following is a mechanism of bacterial resistance to aminoglycosides that does not involve changes to the antibiotic?

    <p>Mutations within the ribosome</p> Signup and view all the answers

    Study Notes

    Macrolides

    • Macrolides consist of a large cyclic core called a macrocyclic lactone ring, decorated with sugar residues.
    • Macrolides bind tightly to the 50S subunit of the bacterial ribosome, blocking the exit of the newly synthesized peptide.
    • They function similarly to aminoglycosides, targeting ribosomes and preventing protein production.

    Mechanisms of Resistance

    • Resistance to macrolides occurs by three mechanisms:
      • Inhibition of drug entry and accumulation due to difficulty penetrating the outer membrane of aerobic gram-negative bacilli and active efflux pumps in some resistant bacteria.
      • Enzyme-mediated ribosome binding site alteration, such as methylation, which prevents macrolide interaction.
      • Mutation of the ribosome binding site, which rarely occurs.

    Aminoglycosides

    • Aminoglycosides are active against various bacteria, including gram-positive and gram-negative bacteria, as well as mycobacteria.
    • Resistance to aminoglycosides occurs via three mechanisms:
      • Efflux pumps prevent accumulation of the aminoglycoside in the cytosol of the bacterium.
      • Modification of the aminoglycoside prevents binding to the ribosome.
      • Mutations within the ribosome prevent aminoglycoside binding.

    Antimicrobial Activity of Aminoglycosides

    • Aminoglycosides are effective against:
      • Gram-positive bacteria, including Staphylococci, Streptococci, Enterococci, and Listeria monocytogenes.
      • Gram-negative bacteria, including Haemophilus influenzae, Enterobacteriaceae, and Pseudomonas aeruginosa.
      • Mycobacteria, including Mycobacterium tuberculosis and Mycobacterium avium complex.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Learn about the structure and function of macrolides, a type of antibiotic that targets bacterial ribosomes and prevents protein production. Understand how they work and how resistance occurs.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser