week 4

• What is meant by "selective toxicity" in antimicrobial chemotherapy?


  It refers to the ability of a drug to target bacterial cells without harming mammalian cells
• What is the purpose of phenotypic methods in antibiotic susceptibility testing?


  To determine the effectiveness of antibiotics against specific bacteria in vitro
• What recent trends in antimicrobial consumption are discussed in the lecture?


  Recent and predicted trends in antimicrobial consumption and the impact of resistance
• What were some early treatments for infections mentioned in the lecture?

  Oils, quinine, mercury, chaulmoogra oil, and arsenicals
• What was the role of Lister in the treatment of wound infections?


  Lister used carbolic acid to treat wound infections
• Why was carbolic acid considered low efficacy and damaging to healthy tissue?


  Because it was not effective enough against infections and harmed surrounding tissues
• What was the significance of sulfa drugs in the 1930s?


  They had a limited spectrum of activity against infections
• What does a bactericidal agent do?


  It kills bacteria
• What is the difference between bactericidal and bacteriostatic agents?


  Bactericidal agents kill bacteria, while bacteriostatic agents inhibit their growth
• What is the first antibiotic discovered?


  Penicillin
• What is the role of Triclosan in antimicrobial applications?


  It targets multiple sites in bacterial membranes and cytoplasm
• Who developed arsphenamine (Neosalvarsan) and what was its activity limited to?


  Paul Ehrlich developed it, and its activity was limited to spirochaetes
• How do antibiotics achieve selective toxicity?


  By affecting targets found in bacterial cells that are not present in mammalian cells
• What is the significance of Penicillium chrysogenum in antibiotic production?


  It is the species used for the production of penicillin
• Who is credited with the discovery of streptomycin?

  Selman Waksman
• What does "serendipitous discovery" mean in the context of antibiotic discovery?


  It refers to an accidental discovery that leads to significant findings
• What are the stages of how infections are established?

  1. Attachment to epithelial surface
  2. Penetration of epithelial surface
  3. Interference/avoidance of host defenses
  4. Multiplication in host tissue
  5. Damage of host tissue
• Why do most antibiotics target stage 4 of the infection process?


  Because they kill organisms or slow growth, allowing host defenses to regain control
• What are the mechanisms of action for antibiotics targeting cell walls?


  Beta-lactams, vancomycin, isoniazid, polymyxin, daptomycin
• What is the role of topoisomerase in bacterial cells?


  It is involved in the supercoiling of DNA during replication
• What is the first recorded case of antimicrobial resistance?

  Bedaquiline
• What is the significance of the peptidoglycan layer in bacterial cell walls?


  It provides structural integrity and protection to the bacterial cell
• What are the components of peptidoglycan?


  1. acetylmuramic acid (NAM) and N-acetylglucosamine (NAG)

  
• What is the function of autolysins in bacterial cell wall synthesis?


  They break down the cell wall to allow for growth and division
• How do glycopeptides inhibit bacterial cell wall synthesis?


  By binding to NAM-NAG monomers and inhibiting transpeptidase enzymes
• What is the role of fosfomycin in antibiotic action?


  It inhibits cell wall synthesis
• What is the mechanism of action of beta-lactams?


  They inhibit the transpeptidation process in bacterial cell wall synthesis
• What is the significance of the outer membrane in Gram-negative bacteria?


  It acts as a barrier to many antibiotics
• What is the function of teichoic acids in Gram-positive bacteria?


  They provide structural support and help in cell wall maintenance
• What is the role of lipid carriers in bacterial cell wall synthesis?


  They transport peptidoglycan precursors across the membrane
• How do antibiotics affect the bacterial cell wall?


  They inhibit the synthesis of peptidoglycan, weakening the cell wall
• What is the target of aminoglycosides in bacterial cells?


  They target protein synthesis
• What is the significance of the 60S ribosome subunit in bacterial protein synthesis?


  It is involved in the translation process of protein synthesis
• What is the role of folic acid synthesis enzymes in bacterial metabolism?


  They are essential for the synthesis of nucleic acids
• What is the impact of antibiotic resistance on public health?


  It leads to treatment failures and increased healthcare costs
• What is the newest drug mentioned in the lecture, and what is its use?

  Bedaquiline, used for treating tuberculosis
• Why is it important to understand the mechanisms of action of antibiotics?


  To develop new antibiotics and combat resistance
• How does the discovery of antibiotics contrast between Fleming and Waksman?


  Fleming's discovery was serendipitous, while Waksman's was systematic
• What is the significance of the timeline of antibiotic discovery from 1930 to 2015?


  It shows the progression and challenges in developing new antibiotics over time
• What are the implications of antibiotic resistance for future treatments?


  It necessitates the development of new antibiotics and alternative therapies