Antimicrobial Drugs and Antibiotics
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Questions and Answers

What is the primary function of antibiotics?

  • To enhance bacterial growth
  • To boost the immune system
  • To kill or inhibit the growth of bacteria (correct)
  • To block viral infections

    • What does the term 'zone of inhibition' refer to?

  • A measure of bacterial growth speed
  • The area around antibiotic discs where bacteria cannot grow (correct)
  • The concentration level of the antibiotic
  • The area where bacteria are resistant to antibiotics

    • Which type of antibiotics only affects a specific group of microbes?

  • Broad-spectrum antibiotics
  • Narrow-spectrum antibiotics (correct)
  • Bactericidal antibiotics
  • Bacteriostatic antibiotics

    • Why can broad-spectrum antibiotics lead to drug resistance?

    <p>They kill off many types of bacteria, including beneficial ones (D)</p> Signup and view all the answers

    What is one disadvantage of using broad-spectrum antibiotics in children?

    <p>Increased risk of developing childhood asthma (D)</p> Signup and view all the answers

    Which class of antibiotics inhibits protein synthesis at 70S ribosomes?

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

    Which component is essential for all penicillin types?

    <p>b-lactam ring (A)</p> Signup and view all the answers

    How does antibiotic concentration in the disk affect the zone of inhibition?

    <p>Higher concentrations typically create larger zones (C)</p> Signup and view all the answers

    Which antibiotic is used specifically to treat tuberculosis?

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

    What mechanism do beta-lactamases use to provide antibiotic resistance?

    <p>Hydrolyze beta-lactam drugs (B)</p> Signup and view all the answers

    Which class of drugs inhibits DNA gyrase?

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

    What is inherent resistance?

    <p>Natural resistance due to physiological characteristics (C)</p> Signup and view all the answers

    Which of the following is an example of an antihelminthic drug?

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

    Which of the following antifungals is classified as a triazole?

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

    What group do NRTIs belong to?

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

    How do efflux pumps contribute to antibiotic resistance?

    <p>They pump antibiotics out of the cell (D)</p> Signup and view all the answers

    Study Notes

    Antimicrobial Drugs

    • Antimicrobial drugs treat microbial infections.
    • Antibiotics kill or inhibit bacterial growth, treating bacterial infections.

    Antibiotics

    • Fight pathogens
    • Interfere with cell wall formation
    • Many are obtained from bacteria or fungi
    • Others are synthesized

    History of Antibiotics

    • The first antibiotic's discovery was accidental.
    • In 1928, Alexander Fleming, a Scottish biologist, accidentally contaminated a petri dish with a fungus.
    • He observed a clear area of no bacterial growth where the fungus contaminated the plate.

    Zone of Inhibition

    • If an antibiotic stops bacterial growth or kills bacteria, a clear zone forms around the antibiotic disk where no bacterial growth occurs.
    • Factors affecting zone size include:
      • Drug diffusion rate
      • Drug concentration
      • Type of microorganism
      • Type of drug

    Narrow and Broad-Spectrum Antibiotics

    • Narrow-spectrum: Affect specific microbes (e.g., gram-positive cells).
      • Examples: Clarithromycin, Clindamycin, Erythromycin
      • Advantages: Less likely to harm normal body microbes, reducing the risk of superinfection. So, only use if the causative organism is known.
    • Broad-spectrum: Affect a wide range of microbes.
      • Examples: Azithromycin, Amoxicillin, Vancomycin, Levofloxacin, Streptomycin, Tetracycline, Chloramphenicol
      • Disadvantages: Can harm normal body microbes, increasing the risk of superinfection. Also, can lead to drug resistance.
      • Children receiving broad-spectrum in the first year of life may increase risk of developing childhood asthma.

    Antibiotic Targets

    • Bacterial cell wall
    • Bacterial plasma membrane
    • Bacterial protein synthesis
    • Bacterial nucleic acids
    • Bacterial metabolism

    Inhibitors of Cell Wall Synthesis

    • Penicillins contain a beta-lactam ring.
    • Natural penicillins, produced by Penicillium, are effective against gram-positive bacteria.

    Inhibitors of Protein Synthesis

    • Aminoglycosides, tetracyclines, chloramphenicol, and macrolides inhibit protein synthesis at 70S ribosomes.

    Inhibitors of Nucleic Acid Synthesis

    • Rifamycin inhibits mRNA synthesis, used to treat tuberculosis.
    • Quinolones and fluoroquinolones inhibit DNA gyrase, used to treat urinary tract infections.

    Antibiotic Resistance

    • Resistance can be inherent or acquired.
    • Inherent: Some bacteria are naturally resistant due to physiological characteristics.
    • Acquired: Bacteria acquire resistance through the transfer of resistance genes or spontaneous chromosomal mutations.

    Mechanisms of Antibiotic Resistance

    • Production of enzymes (e.g., beta-lactamases, aminoglycoside-modifying enzymes, chloramphenicol acetyl transferase).
    • Mutation, altering proteins like PBPs.
    • Efflux pumps, removing antibiotics from bacteria.

    Allergy Testing

    • Used to identify substances causing allergic reactions.
    • Methods: Skin prick test and batch test.

    Antifungal Drugs

    • Used to treat and prevent fungal infections (mycoses).
    • Types: Polyenes, Imidazoles, Triazoles, Allylamines, Inhibitors.

    Antiretroviral Drugs

    • Classified into five groups, targeting specific viral processes:
      • NRTIs (Nucleoside/Nucleotide Reverse Transcriptase Inhibitors)
      • NNRTIs (Non-Nucleoside Reverse Transcriptase Inhibitors)
      • Protease Inhibitors
      • Entry Inhibitors
      • Integrase Inhibitors

    Antiprotozoan and Antihelminthic Drugs

    • Chloroquine and quinacrine stop DNA synthesis by intercalation.
    • Metronidazole treats a wide variety of bacterial and parasitic infections by stopping growth.
    • Niclosamide treats cestodes, parasites infecting humans and animals.

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    Related Documents

    Lecture Notes 6.7 - Antimicrobial Drugs PDF

    Description

    Explore the world of antimicrobial drugs and their impact on treating microbial infections. Learn about the history of antibiotics, the mechanism of action, and the concept of the zone of inhibition. This quiz also covers the difference between narrow and broad-spectrum antibiotics, providing a comprehensive overview of this essential topic in microbiology.

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