ANTIMICROBIALS

1. AmbashRiaz AdeelaHussain SohailSamual ANTIMICROBIALS

2. Overview • What are Antimicrobials? • Classification of Antimicrobials • What are Antibiotics? • Classification of Antibiotics • Example of Penicillin • What are Antivirals? • What are Antifungals? • What are Ant parasites? • Antimicrobial Therapy • Antimicrobial Resistance • Side Effects of Antimicrobials • Modern research about Antimicrobials • Case Study

3. Anti-microbial • An anti-microbial is a substance that kills or inhibits the growth of microorganisms. • Bacteria • Fungi • Protozoans

4. Anti-microbial • Natural • Fungi- Penicillin, Griseofulvin • Bacteria- Polymixin, Bacitracin (Bacillus) - Tetracycline, Chloramphenicol streptomycin (Actinomycetes) • Synthetic

5. Mode of Action • Inhibit the cell wall synthesis • Cause leakage from cell membrane • Inhibit protein synthesis • Cause misreading of mRNA code and affect permeability • Interfere with DNA • Interfere with metabolism

6. Classification • Antibiotics • Antifungals • Antiviruls • Antiprasitics

7. Antibiotics

8. Antibiotics • Antibiotics are also known as antibacterials • Antibiotics are medicinal products that have an anti-bacterial effect. • Antibiotics are widely used in the prevention and treatment of infectious diseases. • The most widely known antibiotic is perhaps penicillin

9. What are antibiotics for? • An antibiotic is given for the treatment of an infection caused by bacteria. • They are not effective against viruses. • Important to know whether it is caused by bacteria or a virus

10. Classification of antibiotics • The antibiotics are classified according to three criteria • According to spectrum • According to mode of action

11. According to spectrum • The spectrum means the number of the organisms affected by the same drug • There are two type of spectrum Narrow spectrum antibiotics Wide spectrum antibiotics

12. According to mode of action • Bactericidal • Bacteriostatic

13. Penicillin

14. History • 1896- Ernest Duchesne- first discover penicillin • 1928- Alexander Fleming- rediscover it accidentally •  Howard Florey and Ernst Chain- isolated the bacteria-killing substance  • 1941- Charles Fletcher- first applied on a patient

15. Mechanism • Structurally, penicillins are β-lactam antibiotics • Which directly hit cell wall of bacteria

16. Mechanism Bacterial cell wall • Bacterial cell walls are consisting of a protective peptidoglycan layer. • peptidoglycan layer: N-acetylmuramic acid (NAM) N-acetylglucosamine (NAG) Two enzymes are involved: autolycine transpeptidase

17. Mechanism • Autolysine: break the cross link of peptides • Transpeptidase: cross link the peptidase • Remodeling of cell wall maintain the rigidity of cell wall

18. Mechanism • The penicillins act by inhibiting transpeptidase enzyme. • This enzyme has a site to bind with penicillin – penicilline binding protein. • Unable it to do its function • Loss of integrity of bacterial cell wall • Leak its celluler component • Bacterial cell perish

19. Beta-lactam ring • very unstable and therefore it participates  • Transpeptidase attacks the beta-lactam ring which opens up to give a more stable compound • This compund remains bound to the transpeptidase via covalent linkage and thereby inhibits the enzyme by acylation of the active site.

20. Resistance to penicillin • Mutations in the active site of the transpeptidase enzyme. • use of newer penicillin antibiotics • Many bacteriassysthesise an enzyme named Beta- Lactamase Video ……………….

21. Antivirals

22. Antivirals • Antivirals are drugs that kill or prevent the growth of viruses •  Viral infections are much harder to treat than bacterial infections • Acyclovir is an antiviral drug that targets the herpes virus

23. Viral life cycle • Attachment to a host cell. • Release of viral genes and possibly enzymes into the host cell. • Replication of viral components using host-cell machinery. • Assembly of viral components into complete viral particles. • Release of viral particles to infect new host cells.

24. Anti-viral targeting • antiviral drug design is to identify viral proteins, or parts of proteins, that can be disabled • targets should be unlike any proteins or parts of proteins in humans • The targets should also be common across many strains of a virus, or even among different species of virus in the same family, so a single drug will have broad effectiveness

25. Key characteristics of Antivirals • Able to enter the cell infected with virus • Interfere with viral nucleic acid synthesis or regulation • Some agents interfere with ability of virus to bind to cells • Some agents stimulates the body’s immune system

26. Interferons • Protein- made and released by host cells • belong to the large class of glycoproteins known as cytokines

27. Functions • activate immune cells natural killer cells macrophages • increase recognition of infection or tumor cells • increase the ability of uninfected host cells to resist new infection by virus

28. Mode of action • An infected cell releases interferons • the infected cell can warn neighboring cells of a viral presence by releasing interferon • The neighboring cells, in response to interferon, produce large amounts of an enzymes • Several different types of interferon are now approved for use in humans.

29. Questions???? Thank you