Antibiotic Terminology and History
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Questions and Answers

What is the primary function of lysozyme?

  • Stimulate leukocyte production
  • Inhibit protein synthesis
  • Enhance nucleic acid synthesis
  • Break down peptidoglycan (correct)

    • Which of the following antibiotics is known for its broad spectrum?

  • Tetracycline (correct)
  • Penicillin
  • Vancomycin
  • Oxacillin

    • Which antibiotics are specifically classified as cell wall inhibitors?

  • Macrolides
  • β-lactams (correct)
  • Aminoglycosides
  • Tetracyclines

    • How do bacteriostatic antibiotics differ from bactericidal antibiotics?

    <p>They inhibit bacterial growth and reproduction.</p> Signup and view all the answers

    Which substance is derived from garlic and has a bactericidal effect?

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

    What characterizes broad-spectrum antibiotics?

    <p>They inhibit several bacterial groups.</p> Signup and view all the answers

    What is the minimum inhibitory concentration (MIC)?

    <p>It is the lowest concentration of an antibiotic that inhibits bacterial growth.</p> Signup and view all the answers

    Which scientist is credited with discovering the first antibiotic?

    <p>Alexander Fleming</p> Signup and view all the answers

    What does the term 'selective toxicity' refer to?

    <p>The ability of an antibiotic to target certain microorganisms without harming human cells.</p> Signup and view all the answers

    Multidrug-resistant bacteria are defined as bacteria that are resistant to how many classes of antimicrobial agents?

    <p>All classes except one or two</p> Signup and view all the answers

    What is the primary use of antibiotics produced by bacteria?

    <p>Topical applications for local infections</p> Signup and view all the answers

    Which of the following antibiotics is produced by Bacillus subtilis?

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

    What type of bacteria do polymyxin B primarily target?

    <p>Gram-negative bacteria</p> Signup and view all the answers

    Which of the following is a semisynthetic 5th generation penicillin?

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

    Which penicillin is known to be β-lactamase resistant?

    <p>Piperacillin + Tazobactam</p> Signup and view all the answers

    What is the primary mechanism of action of glycopeptides like vancomycin?

    <p>Inhibit synthesis of peptidoglycan</p> Signup and view all the answers

    What is the spectrum of activity for 3rd generation penicillins?

    <p>Broad spectrum including Pseudomonas spp.</p> Signup and view all the answers

    Which of the following combinations provides β-lactamase resistance?

    <p>Ticarcillin + Clavulanate</p> Signup and view all the answers

    Which antibiotic is particularly effective against Gram-negative aerobes?

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

    Which is true about carboxypenicillins?

    <p>They are semisynthetic and include Ticarcillin.</p> Signup and view all the answers

    What is a significant side effect of chloramphenicol?

    <p>Bone marrow toxicity</p> Signup and view all the answers

    Which one of the following is a characteristic of 6th generation penicillins?

    <p>They bind to different Penicillin Binding Proteins (PBPs).</p> Signup and view all the answers

    How do macrolides exert their effect on bacterial cells?

    <p>By binding reversibly to the 50s ribosomal subunit</p> Signup and view all the answers

    Which antibiotic is specifically noted for its broad activity against both Gram-positive and Gram-negative bacteria?

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

    Which penicillin is especially used for cases involving Pseudomonas spp.?

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

    What is the primary coverage of aminopenicillins?

    <p>A mixture of Gram+ and Gram- bacteria</p> Signup and view all the answers

    What is the primary purpose of cilastatin when combined with imipenem?

    <p>Prevent rapid renal inactivation</p> Signup and view all the answers

    Which of the following antibiotics is known for rapidly developing resistance?

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

    What type of bacteria do carbapenems primarily target?

    <p>Broad spectrum including both Gram-positive and Gram-negative bacteria</p> Signup and view all the answers

    Which adverse effect is specifically associated with chloramphenicol?

    <p>Disturbances in red cell maturation</p> Signup and view all the answers

    What is a key principle in the rational selection of antimicrobial drugs?

    <p>Performing susceptibility testing in vitro</p> Signup and view all the answers

    Which type of bacteria are classified in the 1st priority group for antibacterial resistance?

    <p>Acinetobacter baumannii</p> Signup and view all the answers

    What is a common consequence of the uncontrolled use of antibiotics?

    <p>Development of antibacterial resistance</p> Signup and view all the answers

    Which of the following adverse effects is associated with tetracycline?

    <p>Tooth discoloration</p> Signup and view all the answers

    Which of the following bacteria is resistant to fluoroquinolones according to the second priority group?

    <p>Neisseria gonorrhoeae</p> Signup and view all the answers

    What condition can rifampicin lead to as a toxic reaction?

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

    Which of the following is NOT a criterion for the rational selection of antimicrobial drugs?

    <p>Avoiding all side effects</p> Signup and view all the answers

    Study Notes

    Antibiotic Terminology

    • Broad Spectrum: Effective against a wide range of bacterial species.
    • Narrow Spectrum: Effective against a limited range of bacterial species.
    • Minimum Inhibitory Concentration (MIC): The lowest concentration of an antibiotic that prevents the growth of a specific bacteria strain.
    • Multidrug-Resistant Bacteria: Resistant to one or more classes of antimicrobial agents, often resistant to all but one or two commercially available agents (excluding Mycobacterium tuberculosis).

    History of Antibiotics

    • Paul Erlich (late 19th century): First observed and detected antibacterial substances, introducing the concept of selective toxicity.
    • Alexander Fleming (1928): Discovered the first antibiotic, penicillin, by observing the inhibition of Staphylococcus aureus growth near a colony of Penicillium notatum mold.

    Classification of Antibacterial Substances

    • Origin:
      • Microorganisms:
        • Fungi: Produce penicillin and cephalosporin antibiotics, effective against bacteria.
        • Atypical Bacteria (Actinomyces): Produce a range of antibiotics effective against bacteria, fungi, and tumor cells.
        • Bacteria: Produce antibiotics against other bacteria.
      • Human and Animal Cells: Produce substances like lysozyme and spermine with antibacterial properties.
      • Plant Cells: Produce volatile substances with bactericidal effects, such as allicin (garlic), allilcep (onion), and raphanin (radish).

    Classification Principles of Antibiotics

    • Spectrum:
      • Broad Spectrum: Effective against a wide range of bacteria (e.g., tetracycline).
      • Narrow Spectrum: Effective against a limited range of bacteria (e.g., oxacillin).
    • Mode of Action:
      • Bactericidal: Directly kill bacteria.
      • Bacteriostatic: Prevent bacterial growth.
    • Route of Administration:
      • Enteral: Administered orally.
      • Parenteral: Administered by injection.
    • Mechanism of Action:
      • Cell Wall Inhibitors: Inhibit the synthesis of bacterial cell walls.
      • Protein Synthesis Inhibitors: Inhibit the formation of bacterial proteins.
      • Nucleic Acid Synthesis Inhibitors: Inhibit the synthesis of bacterial DNA and RNA.
      • Antimetabolites: Interfere with bacterial metabolic processes.
      • Plasma Membrane Inhibitors: Damage the bacterial cell membrane.

    Cell Wall Inhibitors

    • Beta-Lactams:
      • Penicillins:
        • Mechanism of Action: Bind to transpeptidase, an enzyme essential for peptidoglycan synthesis, preventing bacterial cell wall formation.
        • Spectrum: Broad spectrum (especially in combination with β-lactamase inhibitors):
          • Gram-positive and Gram-negative cocci
          • Gram-positive and Gram-negative rods
          • Anaerobes (except Pseudomonas spp.)
      • Cephalosporins: Similar to penicillin, but differ in structure and spectrum of activity.
      • Carbapenems:
        • Spectrum: Broad spectrum, active against many gram-positive and gram-negative bacteria, and some anaerobes.
      • Monobactams:
        • Spectrum: Narrow spectrum, primarily effective against gram-negative aerobes, particularly Pseudomonas.
    • Glycopeptides (Vancomycin):
      • Mechanism of Action: Inhibit peptidoglycan synthesis.
      • Spectrum: Gram-positive cocci (Staphylococcus, Streptococcus, Enterococcus), and bacteria (Clostridium spp.), including multiresistant organisms (MRSA).
    • Fosfomycin:
      • Mechanism of Action: Inhibit early steps in peptidoglycan synthesis.
      • Spectrum: Broad spectrum, including gram-positive and gram-negative cocci and rods, and multiresistant organisms (ESBL).

    Protein Synthesis Inhibitors

    • Macrolides (Erythromycin, Azithromycin, Clarithromycin):
      • Mechanism of Action: Bind reversibly to the 50s subunit of bacterial ribosomes, inhibiting protein synthesis.
      • Spectrum: Relatively broad, including gram-positive and gram-negative bacteria, and atypical bacteria like Mycoplasma, Chlamydia, and Legionella.
    • Chloramphenicol:
      • Mechanism of Action: Bind reversibly to the 50s subunit of bacterial ribosomes, inhibiting protein synthesis.
      • Side Effect: Bone marrow toxicity, potentially causing aplastic anemia.
      • Spectrum: Broad, including gram-positive and gram-negative bacteria, atypical bacteria like Mycoplasma, Chlamydia, and anaerobes.
    • Clindamycin:
      • Mechanism of Action: Bind reversibly to the 50s subunit of bacterial ribosomes, inhibiting protein synthesis.
      • Spectrum: Gram-positive cocci, including multiresistant organisms (MRSA).

    Antibacterial Resistance

    • Uncontrolled antibiotic use is the primary driver of antibiotic resistance.
    • The Resistance Problem:
      • First Priority Group: Critically High Level
        • Carbapenem-resistant strains: Acinetobacter baumanii, Pseudomonas aeruginosa
        • Extended-spectrum beta-lactamases (ESBL) producing Enterobacteriaceae (e.g., Escherichia coli, Klebsiella pneumoniae).
      • Second Priority Group: High Level
        • Enterococcus spp., vancomycin-resistant (VRE)
        • Staphylococcus aureus, methicillin-resistant (MRSA), vancomycin-resistant (VRSA)
        • Helicobacter pylori, clarithromycin-resistant
        • Campylobacter spp., fluoroquinolone-resistant
        • Salmonellae, fluoroquinolone-resistant
        • Neisseria gonorrhoeae, cephalosporin-resistant, fluoroquinolone-resistant
      • Third Priority Group: Medium Level
        • Streptococcus pneumoniae, penicillin-resistant
        • Haemophilus influenzae, ampicillin-resistant
        • Shigella spp., fluoroquinolone-resistant

    Rational Antibiotic Selection

    • Diagnostic Evaluation: Accurate identification of the causative organism is crucial for effective treatment.
    • Sensitivity Testing: Performing in vitro susceptibility testing to determine which antibiotics are most effective against the identified organism.
    • Dosage and Administration: Choosing the appropriate dose and route of administration for the selected antibiotic.
    • Treatment Duration: Adjusting the antibiotic selection and treatment duration as needed to ensure effectiveness and minimize resistance development.

    Key Points to Remember

    • Antibiotics are powerful tools that can save lives, but their overuse can lead to devastating consequences.
    • Effective antibiotic stewardship programs can help to minimize antibiotic resistance.
    • Continuous research and development is essential for finding new antibiotics and combating resistance.

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    Antibiotics & Antibacterial Resistance PDF

    Description

    This quiz explores essential terminology related to antibiotics, including broad and narrow spectrum efficacy, minimum inhibitory concentration, and multidrug-resistant bacteria. It also highlights significant historical figures like Paul Ehrlich and Alexander Fleming who contributed to the field of antibiotics.

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