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????
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