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Microbiology Student Outline – Chemotherapy and Antibiotics
Chemotherapy and Antibiotics
Reading: Chapter 20
1. Introduction
A. Selective Toxicity
2. Chemotherapy
A. Definitions:
i. Chemotherapeutic Agents
ii. Antibiotics
iii. Spectrum of Microbial Activity
a. Narrow-spectrum Antibiotics
• Penicillin G
b. Broad-spectrum Antibiotics
• Superinfection
* Elimination of competition: Candida albicans
* also, Resistance to Drugs
iv. Bactericidal
v. Bacteriostatic
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Microbiology Student Outline – Chemotherapy and Antibiotics
B. Characteristics of a good chemothereputic agent
i. Selective Toxicity
ii. non-allergenic
iii. disease should not become readily resistant to the drug
iv. host should not destroy, neutralize, or excrete the drug
v. the drug must be able to reach the infection site.
3. Overview of Chemotheraputic Modes of Action (Pull out downloadable handout)
4. Inhibition of Cell Wall Synthesis
A. Penicillin (pp. 559 - 562)
• Antibiotics
• History & Alexander Fleming
i. Structure
ii. Mechanism
• Peptidoglycan
* N-acetylgucosamine
* N-acetylmuramic acid
• Transpeptidase
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Microbiology Student Outline – Chemotherapy and Antibiotics
iii. Draw Backs
a. Anaphylactic Reaction
b. Penicillinase
c. Resistance
• Methicillin
• MRSA (Methicillin -resistant Staphylococcus aureus)
• b-Lactamase Inhibitors (Pull out handout)
iv. Extended Spectrum Penicillins
• Semisynthetic Penicillins
a. Ampicillin
b. Amoxicillin
B. Monobactams
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Microbiology Student Outline – Chemotherapy and Antibiotics
C. Cephalosporins (pp. 561 - 563)
i. General Information
ii. Generations (Partial list, there are now fourth generation cephalosporins):
a. First Generation: Second Generaion: Third Generation:• Cefadroxil • Cefaclor • Cefixime• Cefazolin • Cefamandole • Cefoperazone• Cephalexin • Cefmetazole • Cefotaxime• Cephalothin • Cefonicid • Cefpodoxime• Cephapirin • Ceforanide • Ceftazidime• Cephradine • Cefotetan • Ceftizoxime
• Cefoxitin • Ceftriaxome• Cefprozil• Cefuroxime• Loracarbef
ii. Mechanism
iii. Side Effects
D. Bacitracin (p. 563)
i. General Information
ii. Mechanism
iii. Side Effects
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Microbiology Student Outline – Chemotherapy and Antibiotics
E. Vancomycin (p. 563)
i. General Information
ii. Mechanism
iii. VRE (Vancomycin-resitant Enterococci)
5. Mycobacterial Antibiotics (p. 463)
A. Mycobacteria Cell walls
i. Mycolic Acids
B. Isoniazid (INH)
i. Mycobacterium tuberculosis
C. Ethambutol
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Microbiology Student Outline – Chemotherapy and Antibiotics
6. Inhibitors of Protein Synthesis
A. Chloramphenicol (pp. 563 - 565)
i. General Information
ii. Mechanism
iii. Side Effects
B. Aminoglycosides (p. 565)
i. General Information
• Amino Group ( - NH2 )
ii. Mechanism
iii. Administration
iv. Side Effects
• Neomycin
Relative ototoxicity:
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Microbiology Student Outline – Chemotherapy and Antibiotics
neomycin > streptomycin > kanamycin > amikacin, gentamicin, tobramycin, netilmicin
C. Tetracyclines (p. 565)
i. General Information
ii. Mechanism
iii. Side Effects
iv. Heart Attacks
D. Macrolides (Erythromycin) (p. 566)
i. General Information
ii. Mechanism
iii. Side Effects
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Microbiology Student Outline – Chemotherapy and Antibiotics
iv. Resistance
E. Streptogramins
F. Oxazolildinones
7. Disruption of the Plasma (Cell) Membrane (p. 566)
A. Polymyxins
i. General Information
ii. Mechanism
iii. Side Effects
8. Inhibition of Nucleic Acid Synthesis (p. 567)
A. Rifampin
i. General Information
ii. Mechanism
iii. Side Effects
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Microbiology Student Outline – Chemotherapy and Antibiotics
9. Competitive Inhibition (pp. 567 - 568)
A. Sulfonamides
i. How they work
• Synergism
ii. Methods of Resistance
NH2 NH2
COOH SO2NH2
PABA Sulfonilamide
B. Trimethoprim
PABABlocked by Sulfonamides
Dihydrofolic AcidBlocked by Trimethoprim (Dihydroloate Reductase)
Tetrahydrofolic Acid
• Bactrim
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Microbiology Student Outline – Chemotherapy and Antibiotics
10. Antifungal Drugs (pp. 567 - 569)
A. Griseofulvin (p. 569)
i. General Information
ii. Mechanism
iii. Side Effects
?? B. Nystatin
i. General Information
• Intestinal Candidiasis
ii. Mechanism
J. Lincomycin - and Clindamycin i. General Information ii. Mechanism iii. Side Effects
11. Antiviral Drugs (pp. 567 - 571)
A. Nuceoside and Nucleotide Analogs
i. Acyclovirii. Gamcicloviriii. Ganciclovir
B. Protease Inhibitors
C. Integrase Inhibitors
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Microbiology Student Outline – Chemotherapy and Antibiotics
D. Fusion Inhibitors
12. Antiprotozoan Durgs (p. 571)
A. Quinine
B. Metronidazole (Flagyl)
13. Antihelminthic Drugs (p. 571)
14. Drug Resistance (p. 572 - 573)
A. How Bacterial may become resistant
B. Determinative Assays
i. Kirby-Bauer Susceptibility Test
• Antibiotic Disks
• Zone of Inhibition
ii. Tube Dilution Method
a. Minimum Inhibitory Concentration (MIC)
B. Antibiotic Resistance and Abuse (p. 575)
i. Acquired Resistance
ii. Hospitals
iii. Livestock Feeds
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