1 / 72

MECHANISMS OF ACTION OF ANTIBIOTICS

MECHANISMS OF ACTION OF ANTIBIOTICS. BACTERIOSTATIC AGENTS. Sulfonamides Drugs inhibiting protein synthesis except aminoglycosides (macrolides, chloramphenicol, tetracyclines etc). BACTERICIDAL AGENTS. Beta lactams (penicillins, cephalosporins, imipenem) Trimethoprim/sulfamethoxazole

theophilus
Download Presentation

MECHANISMS OF ACTION OF ANTIBIOTICS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MECHANISMS OF ACTION OF ANTIBIOTICS

  2. BACTERIOSTATIC AGENTS • Sulfonamides • Drugs inhibiting protein synthesis except aminoglycosides (macrolides, chloramphenicol, tetracyclines etc).

  3. BACTERICIDAL AGENTS • Beta lactams (penicillins, cephalosporins, imipenem) • Trimethoprim/sulfamethoxazole • Vancomycin • Fluoroquinolones • Aminoglycosides

  4. MECHANISMS OF ACTION • Inhibitors of cell wall synthesis • Drugs altering cell membranes • Inhibitors of protein synthesis • Antimetabolites • Inhibitors of nucleic acid synthesis.

  5. DRUGS INHIBITING CELL WALL SYNTHESIS • Penicillins • Cephalosporins • Imipenem • Vancomycin • Fosfomycin β-lactams

  6. www.uccs.edu/

  7. Dividing Bacteria Division Plus penicillin Emerging Spheroplast Growth Growth site Spheroplast

  8. www.chem.qmul.ac.uk/

  9. www.uccs.edu/

  10. Glycopeptide Polymer Glycopeptide Polymer Mur NAc Transpeptidase X D-Alanine Mur NAc X Glycopeptide Polymer X

  11. Penicillin Binding Proteins Transpeptidases Penicillin Carboxypeptidases Endopeptidases

  12. AUTOLYSINS

  13. All Beta lactam antibiotics act by the same mechanism

  14. PENICILLINS ACTIVE VS GRAM - BACTERIA

  15. S CH3 O C CH3 R N C C C N C COOH O OH Penicilloic Acid S CH3 O C CH3 R C N C C C N C COOH O Penicillinase (β-Lactamase)

  16. COMBINATIONS WITH BETA LACTAMASE INHIBITORS • Penicillin plus a beta lactamase inhibitor.

  17. CEPHALOSPORINS AND IMIPENEM • Same mechanism of action as penicillins but bind to different binding proteins.

  18. FOSFOMYCIN • Inhibits peptidoglycan synthesis at an earlier stage than where the beta lactams act.

  19. VANCOMYCIN

  20. NAG-NAM D-ALA L-GLU LYS Enzyme Enzyme D-ALA D-ALA Transpeptidase PENICILLINS X

  21. NAG-NAM D-ALA L-GLU LYS Enzyme D-ALA D-ALA Transglycosylase VAN

  22. RESISTANCE TO BETA LACTAMS • Penicillinase • Beta lactamases

  23. S CH3 O C CH3 R N C C C N C COOH O OH Penicilloic Acid S CH3 O C CH3 R C N C C C N C COOH O Penicillinase

  24. METHICILLIN RESISTANCE • Altered PBP’s.

  25. RESISTANCE TO OTHER BETA LACTAM ANTIBIOTICS • Most prevalent mechanism is hydrolysis by beta lactamases. • Cephalosporins have variable susceptibility to βlactamases. • Some even induce formation of the enzymes.

  26. RESISTANCE TO VANCOMYCIN

  27. ANTIBIOTICS AFFECTING CELL MEMBRANES • Polymyxins • Daptomycin

  28. POLYMYXINS • Surface active amphipathic agents. • Interact strongly with phospholipids and disrupt the structure of cell membranes.

  29. DAPTOMYCIN • Depolarizes the cell membrane

  30. ANTIBIOTICS INHIBITING PROTEIN SYNTHESIS • Macrolides • Clindamycin • Linezolid • Streptogramins • Chloramphenicol • Tetracyclines • Aminoglycosides

  31. Eucaryotic Ribosome 50S 60S 30S 40S 80S--M.W. 4,200,000 Procaryotic Ribosome 70S--M.W.2,500,000

  32. Antibiotics binding to the 50S ribosomal subunit and inhibiting protein synthesis • Erythromycin and other macrolides • Chloramphenicol • Linezolid • Streptogramins

  33. Antibiotics binding to the 30S ribosomal subunit and inhibiting protein synthesis • Aminoglycosides • Tetracyclines

  34. CLEanSAT

  35. Macrolides (Erythromycin, Azithromycin and Clarithromycin)

  36. A Nascent polypeptide chain 50S Transferase site aa mRNA template P 30S MACROLIDES TRANSLOCATION

  37. CHLORAMPHENICOL

  38. Chloramphenicol A Nascent polypeptide chain 50S Transferase site aa mRNA template P 30S Mechanism of action of Chloramphenicol

  39. INITIATION

  40. STREPTOGRAMINS • Quinupristin/Dalfopristin (30:70)

  41. A Nascent polypeptide chain 50S QUINUPRISTIN (MACROLIDE) Transferase site aa mRNA template P 30S DALFOPRISTIN

More Related