CHAPTER 9

• What is the source of Cephalosporins?

  Cephalosporium species
• Which fungus produces Griseofulvin?

  Penicillium griseofulvum
• What are the sources of Penicillin?

  Penicillium notatum and P. chrysogenum
• What antibiotic is produced by Streptomyces nodosus?

  Amphotericin B
• Which Streptomyces species produces Chloramphenicol?

  Streptomyces venezuelae
• What antibiotic is derived from Streptomyces erythreus?

  Erythromycin
• Which antibiotic is produced by Streptomyces avermitilis?

  Ivermectin
• What antibiotic does Streptomyces griseus produce?

  Streptomycin
• Which antibiotic is produced by Streptomyces Kanamyceticus?

  Kanamycin
• What antibiotic does Streptomyces fradiae produce?

  Neomycin
• Which antibiotic is derived from Streptomyces noursei?

  Nystatin
• What antibiotic does Streptomyces mediterranei produce?

  Rifampin
• Which antibiotic is produced by Streptomyces aureofaciens?

  Tetracycline
• What antibiotic is derived from Streptomyces orientalis?

  Vancomycin
• Which antibiotic does Streptomyces antibioticus produce?

  Vidarabine
• What antibiotic is produced by Micromonospora species?

  Gentamicin
• Which antibiotic is derived from Bacillus licheniformis?

  Bacitracin
• What antibiotic does Bacillus polymyxa produce?

  Polymyxins
• Which antibiotic is produced by Bacillus brevis?

  Tyrocidin
• How do bacteria become resistant to antibiotics?

  Through natural selection, mutation, and horizontal gene transfer

  
• What is the process of natural selection in bacteria?

  Bacteria that survive antibiotics reproduce and pass on resistance genes
• What are the two main ways bacteria can become resistant to antibiotics?

  Mutation and horizontal gene transfer

  
• What is mutation in the context of antibiotic resistance?

  Changes in bacterial DNA that affect antibiotic target proteins
• What is horizontal gene transfer?

  Sharing of genetic material between bacteria, including resistance genes

  
• What factors contribute to the development of antibiotic resistance?

  Overuse of antibiotics, poor infection control, and agricultural use
• Why is overuse of antibiotics a problem?

  It increases the likelihood of bacteria developing resistance
• How does poor infection prevention contribute to antibiotic resistance?

  It allows the spread of antibiotic-resistant bacteria
• How does agricultural use of antibiotics contribute to resistance?

  It promotes growth in livestock and can spread resistance to humans
• What is an antibiotic?

  A chemical substance produced by microorganisms that is detrimental to other microorganisms
• What does selective toxicity mean?

  To kill or inhibit the infecting microorganism without damaging the host
• What does bacteriostatic mean?

  Capable of inhibiting the growth of bacteria
• What does bactericidal mean?

  Capable of killing bacteria
• What is narrow spectrum antibiotic?

  Effective against a limited range of organisms
• What is broad spectrum antibiotic?

  Acts against a larger group of organisms, e.g., Gram-positive and Gram-negative
• What are the six selection questions for antimicrobial agent selection?

  1. Is an antimicrobial agent required?
  2. Where is the infection located?
  3. Which pathogen(s) are usually found at the infection site?
  4. Which antimicrobial agent has the necessary pharmacokinetic properties?
  5. What dose and route are necessary for the desired effect?
  6. How long should the treatment be?
• What are the classifications of antibiotics based on their mechanism of action?

  1. Inhibition of cell wall synthesis
  2. Impairment of cell membrane function
  3. Inhibition of protein synthesis
  4. Inhibition of DNA synthesis and replication
  5. Inhibition of DNA-dependent RNA polymerase
  6. Inhibition of folate/folic acid and consequently DNA synthesis

  
• What antibiotics inhibit cell wall synthesis?

  Penicillins, cephalosporins, vancomycin, bacitracin, cycloserine
• Which antibiotics impair cell membrane function?

  Polymyxin B, colistin, tyrocidin, amphotericin B, nystatin
• What antibiotics inhibit protein synthesis at the 30S ribosomal subunit?

  Aminoglycosides, tetracyclines, spectinomycin
• Which antibiotics inhibit protein synthesis at the 50S ribosomal subunit?

  Chloramphenicol, macrolides, lincosamides