L-19 Antibacterial Cell Wall Drugs Quiz
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

Which statement accurately describes why penicillins and aminoglycosides cannot be administered simultaneously in the same IV fluid?

  • Aminoglycosides neutralize the antibacterial properties of penicillins.
  • Penicillins degrade aminoglycosides, reducing their effectiveness.
  • The positive charge of aminoglycosides and the negative charge of penicillins cause a physical interaction, leading to precipitation. (correct)
  • The combination leads to decreased permeability of bacterial cell walls

    • Which of the following beta-lactam antibiotics is primarily administered orally due to its acid stability?

  • Ticarcillin
  • Mezlocillin
  • Piperacillin
  • Carbenicillin indanyl (correct)

    • Which of the following represents a mechanism of bacterial resistance to penicillins that does not involve beta-lactamase activity?

  • Chromosome mediated enzymatic inactivation
  • Plasmid mediated enzymatic hydrolysis.
  • Decreased permeability of the bacterial cell wall. (correct)
  • Hydrolysis via a naturally occurring bacterial response

    • Which of the following is a characteristic unique to piperacillin among the listed ureido-penicillins?

    <p>It is the most potent of the ureido-penicillins. (A)</p> Signup and view all the answers

    Which of the following is the primary role of beta-lactamase inhibitors when co-administered with penicillins?

    <p>To prevent the breakdown of penicillins by beta-lactamase enzymes. (B)</p> Signup and view all the answers

    Which statement regarding the use of carbenicillin in the US is correct?

    <p>It is only available for oral use. (C)</p> Signup and view all the answers

    What is the primary purpose of using procaine penicillin G and benzathine penicillin G?

    <p>To provide a long-acting, sustained release of penicillin. (A)</p> Signup and view all the answers

    A patient with a confirmed Pseudomonas infection requires intravenous antibiotic therapy. Based on information from the provided text, which antibiotic would be the most appropriate choice?

    <p>Piperacillin/tazobactam (A)</p> Signup and view all the answers

    Which penicillin is specifically effective against aerobic gram positive bacilli, specifically Listeria?

    <p>Ampicillin (A)</p> Signup and view all the answers

    Which of the following penicillins can be administered via all routes, including intravenous?

    <p>Nafcillin (A)</p> Signup and view all the answers

    Ampicillin and Amoxicillin are classified as extended spectrum penicillins because they are effective against which type of bacteria?

    <p>Gram negative bacilli (C)</p> Signup and view all the answers

    What is a common method to protect penicillins from hydrolysis by beta-lactamases?

    <p>Combining with a beta-lactamase inhibitor (A)</p> Signup and view all the answers

    Which penicillin is known to cause neutropenia and phlebitis as common side effects?

    <p>Oxacillin (C)</p> Signup and view all the answers

    For which specific setting are resistant strains of bacteria often susceptible to vancomycin?

    <p>Nosocomial infections (B)</p> Signup and view all the answers

    Which combination includes amoxicillin and a beta-lactamase inhibitor?

    <p>Augmentin (D)</p> Signup and view all the answers

    Which of the following statements is true regarding dicloxacillin?

    <p>It is highly resistant to penicillinase and effective orally. (C)</p> Signup and view all the answers

    Which antibiotic class contains a structure characterized by a 4-membered ring attached to a thiazolidine ring?

    <p>Natural penicillins (D)</p> Signup and view all the answers

    Which of the following mechanisms do penicillins utilize to exert their antibacterial effects?

    <p>Inhibition of peptidoglycan cross-linking (A)</p> Signup and view all the answers

    What characteristic feature distinguishes cephalosporins from penicillins?

    <p>A 6-membered ring replacing the thiazolidine ring (B)</p> Signup and view all the answers

    Which of the following types of bacteria are expected to be resistant to beta-lactam antibiotics?

    <p>Mycobacteria (C)</p> Signup and view all the answers

    The extended spectrum penicillins are known to effectively target which type of bacteria?

    <p>Gram-negative and anaerobic bacteria (C)</p> Signup and view all the answers

    In the process of bacterial cell wall disruption by penicillins, which of the following proteins do penicillins bind to?

    <p>Penicillin-binding proteins (PBPs) (C)</p> Signup and view all the answers

    Which class of penicillins is primarily designed to combat staphylococcal infections?

    <p>Antistaphylococcal penicillins (D)</p> Signup and view all the answers

    Which of the following is NOT classified as an inhibitor of cell wall synthesis?

    <p>Polymyxins (A)</p> Signup and view all the answers

    Flashcards

    Carbenicillin

    A type of penicillin effective against indole-positive Proteus and Pseudomonas.

    Ticarcillin

    A type of penicillin that is similar to Carbenicillin and also effective against indole-positive Proteus and Pseudomonas.

    Piperacillin

    A type of penicillin that is active against Klebsiella pneumoniae and is considered the most potent penicillin.

    Clavulanic acid

    A type of beta-lactamase inhibitor used to protect penicillins from breakdown.

    Signup and view all the flashcards

    Beta-Lactamase Inhibitors

    These drugs protect penicillin from being broken down by bacterial enzymes called beta-lactamases.

    Signup and view all the flashcards

    Synergism

    A type of drug interaction where two drugs work together to produce a greater effect than either drug could achieve alone.

    Signup and view all the flashcards

    Resistance to Penicillins

    Reasons why bacteria may become resistant to penicillins.

    Signup and view all the flashcards

    Depot Penicillins

    This refers to specific forms of penicillin that are given intramuscularly (IM) and have a prolonged release effect.

    Signup and view all the flashcards

    Beta-lactam antibiotics

    A type of antibiotic that targets bacterial cell wall synthesis.

    Signup and view all the flashcards

    Beta-lactam ring

    A 4-membered ring in the structure of beta-lactam antibiotics.

    Signup and view all the flashcards

    Cephalosporins

    A specific group of beta-lactam antibiotics with a 6-membered ring instead of the thiazolidine ring.

    Signup and view all the flashcards

    Natural penicillins

    A type of beta-lactam antibiotic that includes penicillin G.

    Signup and view all the flashcards

    Antistaphylococcal penicillins

    A type of beta-lactam antibiotic effective against staph bacteria.

    Signup and view all the flashcards

    Extended spectrum penicillins

    A type of beta-lactam antibiotic with wider activity against other bacteria like gram-negative bacteria.

    Signup and view all the flashcards

    Mechanism of action of beta-lactam antibiotics

    The process of beta-lactam antibiotics disrupting cell wall synthesis.

    Signup and view all the flashcards

    Transpeptidases

    Enzymes in bacteria that help in cross-linking the cell wall.

    Signup and view all the flashcards

    Anti-Pseudomonal Penicillins

    A group of penicillins that are specifically effective against Pseudomonas aeruginosa, a common cause of hospital-acquired infections.

    Signup and view all the flashcards

    Oxacillin: Acid Stability

    Oxacillin, a penicillin effective against staphylococcal infections, can be taken orally due to its ability to resist breakdown in the stomach's acidic environment.

    Signup and view all the flashcards

    Nafcillin: Treatment of Serious Staphylococcal Infections

    Nafcillin, a penicillin given intravenously for serious staphylococcal infections, is the preferred choice for treating these infections.

    Signup and view all the flashcards

    Dicloxacillin: Resistance to Penicillinase

    Dicloxacillin, a penicillin highly resistant to penicillinase, an enzyme produced by some bacteria, is effective for oral administration.

    Signup and view all the flashcards

    Ampicillin: Treatment of Listeria Infections

    Ampicillin, an extended spectrum penicillin, is the drug of choice for treating infections caused by Listeria, a type of bacteria that can cause food poisoning.

    Signup and view all the flashcards

    Amoxicillin: Prophylactic Use in Heart Valve Patients

    Amoxicillin, an extended spectrum penicillin, is often used to prevent infections in patients with heart valve problems undergoing dental procedures.

    Signup and view all the flashcards

    Study Notes

    Antibacterial Cell Wall Synthesis and Disruption Drugs

    • Beta-lactam antibiotics include Penicillins, Cephalosporins, Carbapenems, and Monobactams.
    • Other inhibitors of cell wall synthesis and disrupting agents (non-beta-lactams) include Vancomycin, Bacitracin, Cycloserine, Polymyxins, Fosfomycin (Phosphonomycin), etc.

    Beta-Lactam Antibiotics: Structure

    • Beta-lactam antibiotics have a unique 4-membered ring (beta-lactam ring) attached to a thiazolidine ring.
    • The beta-lactam ring has a secondary amino group (RNH).
    • Substituents can be attached to the amino group.
    • Cephalosporins are also beta-lactam antibiotics but have a 6-membered ring instead of a thiazolidine ring.
    • R1 and R2 groups determine the antibiotic's therapeutic activity and toxicity.

    Penicillin Classes

    • Penicillins are divided into three classes:
      • Natural penicillins (e.g., penicillin G)
      • Gram-positive or antistaphylococcal penicillins (e.g., nafcillin)
      • Extended-spectrum penicillins (e.g., ampicillin, amoxicillin, antipseudomonal penicillins)

    Mechanism of Action (MOA)

    • Penicillins inhibit the cross-linking step in bacterial cell wall synthesis.
    • They bind to and inactivate transpeptidases, which are responsible for cross-linking linear glycopeptide strands.
    • This action causes bacterial cell lysis and death, making penicillins bactericidal antibiotics.
    • Penicillins require rapidly growing organisms with peptidoglycan cell walls for their action. Mycobacteria, fungi, protozoa, and viruses are not affected.

    Mechanism of Action (detailed)

    • Penicillins bind to penicillin-binding proteins (PBPs), enzymes involved in cell wall synthesis.
    • Some PBPs are transpeptidases that cross-link cell wall chains.
    • Binding prevents cross-linking.
    • Gram-positive cocci have autolysins that aid in cell wall remodeling.
    • Penicillins can activate autolysins, leading to cell lysis.
    • Gram-positive bacteria easily absorb penicillins.
    • Gram-negative bacteria require lipid-filled channels (porins) for penicillin entry.

    Penicillin G

    • Penicillin G (benzylpenicillin) is used for parenteral treatment of treponemal and clostridium infections.
    • It has good activity against Gram-positive organisms.
    • It is susceptible to beta-lactamases, unstable in acidic environments, and only 30% absorbed from the duodenum.
    • Important drug of choice for gas gangrene (due to Clostridium perfringens).
    • Also used in anthrax, actinomycosis, and listeria infections.

    Antistaphylococcal Penicillins

    • These are resistant to staphylococcal beta-lactamases.
    • Effective against staphylococci and streptococci but not against enterococci, anaerobic bacteria, and gram-negative bacteria.
    • Methicillin, Nafcillin, Oxacillin, Cloxacillin, and Dicloxacillin are examples.

    Extended-Spectrum Penicillins (Ampicillin and Amoxicillin)

    • These penicillins retain the spectrum of other penicillins and are effective against gram-negative bacteria but are destroyed by beta lactamases.
    • Amoxicillin is orally administered and is often the drug of choice for gram-positive bacilli (e.g., Listeria).
    • Used prophylactically in cases of abnormal heart valves and oral surgeries.
    • Beta-lactamase inhibitors, like clavulanate, sulbactam, and tazobactam, are used to prevent their breakdown. (Examples: Augmentin, Unasyn, Zosyn).

    Anti-pseudomonal Penicillins

    • Carbenicillin, ticarcillin, piperacillin, azlocillin, and mezlocillin are effective against Pseudomonas aeruginosa but are sometimes called anti-pseudomonal penicillins.
    • Azlocillin, Mezlocillin, and Piperacillin (ureido-penicillins) are more potent than other comparable drugs.

    Beta-lactamase Inhibitors

    • Clavulanic acid, sulbactam, and tazobactam inactivate beta-lactamases, protecting penicillins from breakdown.

    Synergism

    • Penicillins and aminoglycosides can work synergistically, but cannot be given in the same IV fluid due to opposite charges.

    Causes of Resistance to Penicillins

    • Impermeable cell walls lacking peptidoglycan.
    • Plasmid or chromosomally mediated beta-lactamases.
    • Decreased permeability, and altered penicillin-binding proteins (e.g., methicillin-resistant Staphylococcus).

    Kinetics of Penicillins

    • Administration routes vary, including intramuscular and oral.
    • Penicillin G absorption can be affected by food.
    • Some penicillins cross the placental barrier, some have a great oral absorption, and are primarily excreted thorough the kidneys.
    • Probenecid can inhibit penicillin secretion by the kidneys.

    Adverse Effects of Penicillins

    • Hypersensitivity reactions (e.g., skin rashes, Steven-Johnson syndrome) are common, especially with penicilloic acid and ampicillin.
    • Other adverse effects include diarrhea; potential interstitial nephritis, neurotoxicity; cation toxicity; Eosinophilia; serum sickness; angioedema; superinfections.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Lec 19. Cell Wall Synthesis Inhibitors I, Dr. Panavelil- FS PDF

    Description

    Test your knowledge on various antibacterial drugs targeting cell wall synthesis and disruption. This quiz covers beta-lactam antibiotics, their structures, and the classes of penicillins. Dive into the details of these essential medications and their mechanisms.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser