01-Gen Prin Antibiotics
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Transcript of 01-Gen Prin Antibiotics
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Dr. Korawuth Punareewattana
Dept. of Vet Phar & Tox
Khon Kaen University
Topic 1 : General Principles of Antibiotics
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Contents
Terms
Classifications
Mechanisms of Action
Drug interactions
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Terms
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Terms with specific meanings
Antibacterial drugs
Antifungal drugs
Antiviral drugs
Antiprotozoal drugs
Terms with broad meanings or several meanings
Antibiotics Antibiotics and Synthetic antibacterials
Narrow and Broad senses
Antimicrobial drugs Broad and Narrow senses
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Antibiotic Classifications
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Based on Chemical structure
Based on Class of target microorganism
Based on Antibacterial activity
Based on Bacteriostatic or Bactericidal activity
Based on Time- or Concentration-dependent activity
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Classification based on Chemical Structure
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Beta-lactam antibiotics
Penicillins
Cephalosporins
Carbapenems
Monobactam
Peptide antibiotics
Lincosamides
Pleuromutilins
Streptogramins
Macrolides
Aminoglycosides
Tetracyclines
Chloramphenicol
Sulfonamides and
Diaminopyrimidine
Fluoroquinolones
Miscellaneous
Ionophores
Nitrofurans
Nitroimidazoles
Rifamycins
Oxazolidinones
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Sub-classified by clinical importance
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More commonly used
Beta-lactams
Sulfa-Trimethoprim
Fluoroquinolones
Aminoglycosides
Tetracyclines
Chloramphenicol
Less commonly used
Macrolides
Peptide antibiotics
Lincosamides
Pleuromutilins
Streptogramins
Miscellaneous
Nitroimidazole (Metronidazole)
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Classified byClass of Target Microorganisms
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Narrow-spectrum Bacteria only
Broad-spectrum Bacteria
And Other microorganisms
Mycoplasma
Rickettsia
Protozoa
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Classified by Class of Target Microorganisms
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Class of microorganisms
Drug Bacteria Fungi Mycoplasma Rickettsia Chlamydia Protozoa
Aminoglycosides + - + - - -
Beta-lactams + - - - - -
Chloramphenicol + - + + + -
Fluoroquinolones + - + + + -
Lincosamides + - + - - +/-
Macrolides + - + - + +/-
Oxazolidones + - + - - -
Pleuromutilins + - + - + -
Tetracyclines + - + + + +/-
Streptogramins + - + - + +/-
Sulfonamides + - + - + +
Trimethoprim + - - - - +
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Classified by Antibacterial activity
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Narrow-spectrum Gram-positive Bacteria only or
Gram-negative Bacteria only
Broad-spectrum Gram-positive andGram-negative Bacteria
This classification
is roughly classified
Is relatively compared
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Classified by Antibacterial activity
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Aerobic Bacteria Anaerobic Bacteria
Spectrum Gram + Gram - Gram + Gram - Examples
Very broad + + + + Carbapenems; chloramphenicol; Glycylcyclines
3rd-generation fluoroquinolones
Intermediately broad + + + (+) 3rd and 4thgeneration cephalosporins
+ (+) + (+) 2ndgeneration cephalosporins
(+) (+) (+) (+) Tetracyclines
Narrow + +/- + (+) Ampicillin; amoxicillin; 1st generation cephalosporins
+ - + (+) Penicillin; lincosamides; glycopeptides; streptogramins;
oxazolidones
+ +/- + (+) Macrolides
+/- + - - Monobactams; aminoglycosides
(+) + - - 2ndgeneration fluoroquinolones
(+) (+) - - Trimethoprim-sulfa
- - + + Nitroimidazoles
+ - (+) (+) Rifamycin
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Classification based on Bacteriostatic orBactericidal Activity
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Bacteriostatic drugs
Drugs that inhibit bacterial growth
MIC and MBCare much different i.e. > 10 times
Ex. - Chloramphenicol
- Tetracyclines
Bactericidal drugs
Drugs that kill bacteria
MIC and MBCare so close i.e 2-3 times
Ex. - Beta-lactams
- Aminoglycosides MIC minimum inhibition concentration
MBC - minimum bactericidal concentration
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Classification based onTimeorConcentration dependent activity
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Time-dependent antibiotics
Antibacterial action depends on time of drug exposure
Example drugs
Beta-lactams
Macrolides
Concentration-dependent antibiotics
Antibacterial action depends on drug concentration
Example drugs
Aminoglycosides
Fluoroquinolones
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Mechanisms of Action of Antibiotics
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Mechanisms can be classified into 5 groups
Inhibition of cell wall synthesis
Beta-lactam
Damage to cell membrane function
Polymyxins
Inhibition of nucleic acid synthesis or function
Nitroimidazoles
Fluoroquinolones
Inhibition of protein synthesis
Aminoglycosides, Chloramphenicol, Lincosamides etc.
Inhibition of folic acid synthetase
Sulfonamides
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Drug Interactions
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Antibiotic drug combinations that producesynergistic effectThese are possible mechanisms
Sequential inhibition of successive steps in metabolism
Sequential inhibition of cell wall synthesis
Facilitation of one antibiotics entry by another
Inhibition of inactivation enzymes
Prevention of emergence of resistance populations
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Drug Interactions
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Antibiotic drug combinations that produceantagonistic effectThese are possible mechanisms
Inhibition of bactericidal activity
Competition for drug-binding sites
Inhibition of cell permeability mechanisms
Induction of beta-lactamases by beta-lactam drugs