1. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R O B I O L O G Y a n i n t r o d u c t i o n ninth edition TORTORA  FUNKE  CASE Part A 20 Antimicrobial Drugs

2. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antimicrobial Drugs  Chemotherapy: The use of drugs to treat a disease.  Antimicrobial drugs: Interfere with the growth of microbes within a host.  Antibiotic: A substance produced by a microbe that, in small amounts, inhibits another microbe.  Selective toxicity: A drug that kills harmful microbes without damaging the host.

3. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  1928: Fleming discovered penicillin, produced by Penicillium.  1940: Howard Florey and Ernst Chain performed first clinical trials of penicillin. Figure 20.1

4. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Table 20.1

5. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Table 20.2

6. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Action of Antimicrobial Drugs  Broad-spectrum  Superinfection  Bactericidal  Bacteriostatic

7. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Action of Antimicrobial Drugs Figure 20.2

8. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Action of Antimicrobial Drugs Figure 20.4

9. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Cell Wall Synthesis  Penicillin  Natural penicillins  Semisynthetic penicillins

10. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Penicillins Figure 20.6

11. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Cell Wall Synthesis  Penicillin  Penicilinase-resistant penicillins  Extended-spectrum penicillins  Penicillins +  -lactamase inhibitors  Carbapenems  Monobactam

12. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Cell Wall Synthesis Figure 20.8

13. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Cell Wall Synthesis  Cephalosporins  2nd, 3rd, and 4th generations more effective against gram-negatives Figure 20.9

14. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Cell Wall Synthesis  Polypeptide antibiotics  Bacitracin  Topical application  Against gram-positives  Vancomycin  Glycopeptide  Important "last line" against antibiotic resistant S. aureus

15. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Cell Wall Synthesis  Antimycobacterial antibiotics  Isoniazid (INH)  Inhibits mycolic acid synthesis  Ethambutol  Inhibits incorporation of mycolic acid

16. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Protein Synthesis  Chloramphenicol  Broad spectrum  Binds 50S subunit, inhibits peptide bond formation  Aminoglycosides  Streptomycin, neomycin, gentamycin  Broad spectrum  Changes shape of 30S subunit

17. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Protein Synthesis  Tetracyclines  Broad spectrum  Interferes with tRNA attachment  Streptogramins  Gram-positives  Binds 50S subunit, inhibits translation Figure 20.11

18. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Protein Synthesis  Macrolides  Gram-positives  Binds 50S, prevents translocation  Oxazolidinones  Linezolid  Gram-positives  Binds 50S subunit, prevents formation of 70S ribosome Figure 20.12

19. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Injury to the Plasma Membrane  Polymyxin B  Topical  Combined with bacitracin and neomycin in over-the-counter preparation.

20. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Inhibitors of Nucleic Acid Synthesis  Rifamycin  Inhibits RNA synthesis  Antituberculosis  Quinolones and fluoroquinolones  Ciprofloxacin  Inhibits DNA gyrase  Urinary tract infections

21. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Antibacterial Antibiotics Competitive Inhibitors  Sulfonamides (sulfa drugs)  Inhibit folic acid synthesis  Broad spectrum Figure 5.7

22. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.13