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Antimicrobial compounds
Antiseptics and disinfectants
Antibiotics
Bactericidal vs. bacteriostatic
Bactericidal compounds - kill microorganisms
Bacteriostatic compounds - inhibit or slow growth
Factors influencing effectiveness
Metabolic rate of microorganism
Distribution of drug in body
Side effects
Antiseptics and disinfectants
Most are bactericidal
Too toxic for internal use
Antiseptics and disinfectants
Antiseptics - applied to skin
Disinfectants - applied to inanimate objects
Antibiotics
Low molecular weight compounds ingested or injected
into the body
Produced by bacteria or fungi
Some are synthetic
Antibiotics
Antibiotics
Broad spectrum of activity
Active against many different bacteria
May also attack normal microbiota
Spectrum of activity
Antibiotics
Targets of action
Not present in eukaryotic cells
Different from same molecule in eukaryotic cells
“Magic bullets”
Targets of action
Classes of antibiotics and mechanisms of action
Cell wall synthesis inhibitors
Interfere with peptidoglycan synthesis
Classes of antibiotics and mechanisms of action
Cell wall synthesis inhibitors
Interfere with peptidoglycan synthesis
- lactam antibiotics (e.g. pencillins)
- lactam antibiotics
Classes of antibiotics and mechanisms of action
Cell wall synthesis inhibitors
Interfere with peptidoglycan synthesis
- lactam antibiotics (e.g. pencillins)
Glycopeptides (e.g. vancomycin)
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)
Classes of antibiotics and mechanisms of action
Protein synthesis inhibitors
Aminogylcosides (e.g. streptomycin)
Classes of antibiotics and mechanisms of action
Protein synthesis inhibitors
Aminogylcosides (e.g. streptomycin)
Tetracyclines (e.g. tetracycline)
Classes of antibiotics and mechanisms of action
Protein synthesis inhibitors
Aminogylcosides (e.g. streptomycin)
Tetracyclines (e.g. tetracycline)
Macrolides (e.g. erythromycin)
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)
Classes of antibiotics and mechanisms of action
Inhibition of nucleic acid synthesis
Quinolones - inhibit DNA synthesis
(e.g. ciprofloxacin)
Classes of antibiotics and mechanisms of action
Inhibition of nucleic acid synthesis
Quinolones - inhibit DNA synthesis
(e.g. ciprofloxacin)
Rifampin - inhibits RNA synthesis
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
Classes of antibiotics and mechanisms of action
Inhibition of nucleic acid synthesis
Metronidazole - inhibits DNA synthesis
Must be activated by bacterial protein
Newest antibiotics
Glycyl-glycyl tetracycline
Ketolides (macrolide derivative)
Streptogramins - inhibit protein synthesis
Oxazolidinones - inhibit protein synthesis