1. Antimicrobial compounds Antiseptics and disinfectants Antibiotics

2. Bactericidal vs. bacteriostatic Bactericidal compounds - kill microorganisms Bacteriostatic compounds - inhibit or slow growth

3. Factors influencing effectiveness Metabolic rate of microorganism Distribution of drug in body Side effects

4. Antiseptics and disinfectants Most are bactericidal Too toxic for internal use

5. Antiseptics and disinfectants Antiseptics - applied to skin Disinfectants - applied to inanimate objects

6. Antibiotics Low molecular weight compounds ingested or injected into the body Produced by bacteria or fungi Some are synthetic

7. Antibiotics

8. Broad spectrum of activity Active against many different bacteria May also attack normal microbiota

9. Spectrum of activity

10. Antibiotics Targets of action Not present in eukaryotic cells Different from same molecule in eukaryotic cells “Magic bullets”

11. Targets of action

12. Classes of antibiotics and mechanisms of action Cell wall synthesis inhibitors Interfere with peptidoglycan synthesis

13. Classes of antibiotics and mechanisms of action Cell wall synthesis inhibitors Interfere with peptidoglycan synthesis  - lactam antibiotics (e.g. pencillins)

14.  - lactam antibiotics

15. Classes of antibiotics and mechanisms of action Cell wall synthesis inhibitors Interfere with peptidoglycan synthesis  - lactam antibiotics (e.g. pencillins) Glycopeptides (e.g. vancomycin)

16. Classes of antibiotics and mechanisms of action Cell wall synthesis inhibitors Interfere with peptidoglycan synthesis  - lactam antibiotics (e.g. pencillins) Glycopeptides (e.g. vancomycin) Phosphomycin and bacitracin (topical use)

18. Classes of antibiotics and mechanisms of action Protein synthesis inhibitors Aminogylcosides (e.g. streptomycin)

19. Classes of antibiotics and mechanisms of action Protein synthesis inhibitors Aminogylcosides (e.g. streptomycin) Tetracyclines (e.g. tetracycline)

20. Classes of antibiotics and mechanisms of action Protein synthesis inhibitors Aminogylcosides (e.g. streptomycin) Tetracyclines (e.g. tetracycline) Macrolides (e.g. erythromycin)

21. Classes of antibiotics and mechanisms of action Protein synthesis inhibitors Aminogylcosides (e.g. streptomycin) Tetracyclines (e.g. tetracycline) Macrolides (e.g. erythromycin) Lincosamides (e.g. clindamycin)

25. Classes of antibiotics and mechanisms of action Inhibition of nucleic acid synthesis Quinolones - inhibit DNA synthesis (e.g. ciprofloxacin)

26. Classes of antibiotics and mechanisms of action Inhibition of nucleic acid synthesis Quinolones - inhibit DNA synthesis (e.g. ciprofloxacin) Rifampin - inhibits RNA synthesis

27. Classes of antibiotics and mechanisms of action Inhibition of nucleic acid synthesis Quinolones - inhibit DNA synthesis (e.g. ciprofloxacin) Rifampin - inhibits RNA synthesis Trimethoprim and sulfonamides - inhibit enzymes in synthesis pathway

30. Classes of antibiotics and mechanisms of action Inhibition of nucleic acid synthesis Metronidazole - inhibits DNA synthesis Must be activated by bacterial protein

31. Newest antibiotics Glycyl-glycyl tetracycline Ketolides (macrolide derivative) Streptogramins - inhibit protein synthesis Oxazolidinones - inhibit protein synthesis