Antibiotics and Infection Treatment
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Questions and Answers

What happens when bacteria are resistant to an antimicrobial drug?

  • They become susceptible to other antimicrobial drugs.
  • They die immediately due to the antimicrobial drug.
  • Their growth is not halted by the maximal level of the agent. (correct)
  • Their growth is halted by the maximal level of the agent.

    • What is an example of intrinsic resistance?

  • Bacteria that change their structure to resist antibiotics.
  • Mycoplasma, which lacks a cell wall and is resistant to penicillin. (correct)
  • Bacteria that produce enzymes to break down antibiotics.
  • Bacteria that develop resistance through evolution.

    • What is acquired resistance?

  • The ability of antibiotics to affect the growth of bacteria.
  • A mechanism by which bacteria adapt to antibiotics. (correct)
  • A genetic mutation that makes bacteria susceptible to antibiotics.
  • A natural ability of bacteria to resist antibiotics.

    • What is a result of antibiotic resistance?

    <p>Bacteria evolve to evade the effect of antibiotics.</p> Signup and view all the answers

    What is an example of a mechanism of antibiotic resistance?

    <p>Bacteria changing their structure to resist antibiotics.</p> Signup and view all the answers

    What is a characteristic of intrinsic resistance?

    <p>It is a natural ability of bacteria to resist antibiotics.</p> Signup and view all the answers

    What is a consequence of antibiotic resistance?

    <p>The treatment of bacterial infections becomes more challenging.</p> Signup and view all the answers

    What is a mechanism by which bacteria acquire resistance?

    <p>All of the above.</p> Signup and view all the answers

    What is the primary purpose of antibiotics in medical treatment?

    <p>To treat bacterial infections</p> Signup and view all the answers

    What is the key characteristic of antimicrobial drugs?

    <p>Their selective toxicity</p> Signup and view all the answers

    What is the significance of carefully controlling the concentration of antimicrobial drugs?

    <p>To ensure the microorganism is killed while the host cells are tolerated</p> Signup and view all the answers

    What is the relationship between selective toxicity and the effect of antimicrobial drugs?

    <p>Selective toxicity allows the drug to kill microorganisms without harming host cells</p> Signup and view all the answers

    What is the primary concern in using antimicrobial drugs to treat bacterial infections?

    <p>The development of resistance in microorganisms</p> Signup and view all the answers

    What is the role of antibiotics in treating bacterial infections?

    <p>To kill or inhibit the growth of microorganisms</p> Signup and view all the answers

    What is the significance of relative selective toxicity in antimicrobial drugs?

    <p>It requires careful control of the drug concentration</p> Signup and view all the answers

    What is the major limitation of antimicrobial drugs in treating bacterial infections?

    <p>Their selective toxicity is relative, not absolute</p> Signup and view all the answers

    What is the fundamental characteristic of antibiotic resistance?

    <p>A property of the microbe itself</p> Signup and view all the answers

    What is the primary mechanism by which bacteria can acquire resistance to antibiotics?

    <p>Acquiring DNA from a bacterium that is already resistant</p> Signup and view all the answers

    What is an example of a bacterium that has developed resistance to an antibiotic?

    <p>Mycobacterium tuberculosis resistant to rifamycin</p> Signup and view all the answers

    What is the result of spontaneous mutations in DNA that can lead to antibiotic resistance?

    <p>Insertion, deletion, or substitution of one or more nucleotides within the genome</p> Signup and view all the answers

    What is the term for the transfer of genetic material from one bacterium to another?

    <p>Horizontal gene transfer</p> Signup and view all the answers

    What is the consequence of using a single antibiotic to treat an infection?

    <p>The development of antibiotic resistance</p> Signup and view all the answers

    What is the primary mechanism of DNA transfer from one bacterium to another?

    <p>All of the above</p> Signup and view all the answers

    What is the primary function of enzymes involved in antibiotic resistance?

    <p>Destroying or inactivating the antimicrobial agent</p> Signup and view all the answers

    Which of the following is an example of modified target sites in antibiotic resistance?

    <p>S. pneumoniae resistance to B-lactam drugs</p> Signup and view all the answers

    What is the primary function of efflux pumps in antibiotic resistance?

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

    What is the result of alterations in the major bacterial penicillin binding proteins in S. pneumoniae?

    <p>Decreased binding of the antibiotic to its target</p> Signup and view all the answers

    What is the primary mechanism of antibiotic resistance in gram-negative bacteria?

    <p>Decreased accumulation of the drug through alteration of porins</p> Signup and view all the answers

    Where are the genes encoding efflux pumps typically located?

    <p>On both chromosomes and plasmids</p> Signup and view all the answers

    What is the characteristic of drug efflux pumps in multidrug-resistant cells?

    <p>Broad substrate specificity</p> Signup and view all the answers

    What is the function of B-lactamase enzymes?

    <p>To hydrolytically inactivate the B-lactam ring of penicillins and cephalosporins</p> Signup and view all the answers

    What is the characteristic of TEM-1 B-lactamase?

    <p>It is plasmid-encoded</p> Signup and view all the answers

    What is the function of acetyltransferases?

    <p>To transfer an acetyl group to the antibiotic</p> Signup and view all the answers

    What is the function of esterases?

    <p>To hydrolyse the lactone ring of macrolides</p> Signup and view all the answers

    What is the characteristic of AmpC B-lactamase?

    <p>It is chromosomally encoded and inducible</p> Signup and view all the answers

    What is the consequence of KPC B-lactamase production?

    <p>Resistance to all B-lactams including carbapenems</p> Signup and view all the answers

    What is the characteristic of bacteria that express KPC B-lactamase?

    <p>They often encode resistance to other antibiotic classes</p> Signup and view all the answers

    What is the difference between TEM-1 and AmpC B-lactamases?

    <p>TEM-1 is plasmid-encoded, while AmpC is chromosomally encoded</p> Signup and view all the answers

    Study Notes

    Antibiotics and Bacterial Infections

    • Antibiotics are effective against bacterial infections due to their selective toxicity, which allows them to kill or inhibit microorganism growth without harming the host cells.

    Bacterial Resistance to Antibiotics

    • Bacterial resistance occurs when bacteria evolve to evade the effect of antibiotics through multiple mechanisms.
    • Resistance can be intrinsic or acquired.
    • Intrinsic resistance: bacteria survive antibiotics due to their inherent structure or components, e.g., mycoplasma lacks a cell wall, making it resistant to penicillin.

    Acquired Resistance

    • Bacteria acquire resistance through new genetic mutations or by getting DNA from a resistant bacterium.
    • Example: Mycobacterium tuberculosis resistance to rifamycin.

    Mechanisms of Antibiotic Resistance

    • Genetic alterations:
      • Spontaneous mutations in DNA, e.g., chromosomal alteration by insertion, deletion, or substitution of nucleotides.
      • DNA transfer from one bacterium to another, often encoded in extrachromosomal plasmids.
    • Altered expression of protein in drug-resistant organisms:
      • Modification of target sites, e.g., S. pneumoniae resistance to β-lactam drugs involves alterations in penicillin binding proteins.
      • Decreased accumulation of the drug, e.g., gram-negative bacteria altering porins in their outer membrane.
      • Expression of efflux pumps, responsible for decreased drug accumulation in multidrug-resistant cells.
    • Enzymatic activation:
      • Antibiotic-inactivating enzymes, e.g., β-lactamase, acetyltransferases, and esterases.
      • Examples of β-lactamase include TEM-1, AmpC, extended spectrum β-lactamase (ESBL), and Klebsiella pneumoniae carbapenemase (KPC).

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    Bacterial Resistance to Antibiotics PDF

    Description

    Antibiotics are used to treat bacterial infections. Antimicrobial drugs are effective in treating infections due to their selective properties.

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