1. By :Lecturer Nabeel Ahmed Al anbagi nabeela.alambaki@uokufa.edu.iq
Antimicrobial
By :Lecturer
Nabeel Ahmed Al anbagi

2. Definitions
• Antibiotic—antimicrobials of microbial origin, most of which are produced by molds ,fungi or by bacteria of the genus Streptomyces.
• Antimicrobial, antimicrobic—any substance with sufficient antimicrobial activity that it can be used in the treatment of infectious diseases.

3. Sources of Antimicrobial Agents
1-living source
2-Synthesis source
3- asemisynthetic source

4. several molds of the genus Penicillium, produce pencillin and cephalosporin
Gram-positive bacteria as Streptomyces found in soils and freshwater sediments, which produce several antibiotic as
Streptomycin
tetracyclines
chloramphenicol
erythromycin.

5. Chemically synthesized is compounds synthesized for other purposes and tested for their therapeutic effectiveness in animals. The as sulfonamides,

6. Classification Antimicrobial according mechanism of action
1-Antimicrobics that act on cell wall synthesis.
2-Affect the Cell Membrane.
3-Inhibitors of Protein Synthesis
4-Inhibitors of Nucleic Acid Synthesis
5-Folate Inhibitors

7. Antimicrobial that act on cell wall synthesis.
This group act on The peptidoglycan (murein sac) component of the bacterial cell wall gives it its shape and rigidity.
Most important groups are :-
B-lactams and the glycopeptides

8. B-Lactams groups
Their name derives from the presence of a B- lactam ring in their structure; this ring is essentialfor antibacterial activity.
This group composed from
1-penicillins
2-cephalosporins
3-carbapenems
4-monobactams

9. Penicillins Act on Gram-positive organisms, Gram-negative cocci
1- Penicillin G (benzylpenicillin)
2- Penicillin V (phenoxymethylpenicillin)
3- semi synthetic penicilins ,The penicillinase- resistant penicillins (methicillin, nafcillin, oxacillin)

10. Cephalosporins
Cephalosporins The structure of the cephalosporins confers resistance to hydrolysis by staphylococcal penicillinase and to the B- lactamases of groups of Gram-negative bacilli, which vary with each cephalosporin.
The cephalosporins are classified by generation— first, second, third, or fourth.

11. Example for cephalosporin
cefoxitin
cefaclor
ceftriaxone
cefotaxime
ceftazidime

12. Carbapenems
broadest spectrum of all B-lactam antibiotics. penetration of Gram- and Gram+ bacterial cells and high level of resistance to Blactamases
Monobactams.

13. Glycopeptide Antimicrobics
Two agents, vancomycin and teicoplanin, belong to this group

14. Polypeptide Antibiotics Affect the Cell Membrane2
Polypeptide Antibiotics Affect the Cell Membrane

15. Polypeptide Antibiotics
Both bacitracin and polymyxin B are polypeptide antibiotics produced by Bacillus species.
These antibiotics are quite toxic internally and can cause kidney damage. Therefore, they generally are restricted to topical use, such as on the skin.

16. Antimicrobial Inhibitors of Protein Synthesis3
Antimicrobial Inhibitors of Protein Synthesis

17. 1-Aminoglycosides.
2.Tetracyclines.
3-Chloramphenicol.
4-Macrolides.
5-Clindamycin
6-Streptogramins

18. Aminoglycosides
The aminoglycosides are a group of bactericidal antibiotic compounds that attach irreversibly to the 30S subunit of bacterial ribosomes,
Gentamicin
Tobramycin
Neomycin,
Kanamycin

19. Tetracyclines
The tetracyclines are a group of broadspectrum bacteriostatic antibiotics that act on 30S subunit
Oxytetracycline
Chlortetracyclines
doxycycline

20. 3.Chloramphenicol.
An antibiotic with a broad spectrum acts on 50s subunit .Its discovery from Streptomyces

21. Macrolides.
erythromycin, azithromycin, and clarithromycin, tylosin .They affect protein synthesis at the ribosomal level by binding to the 50S subunit

22. Clindamycin
Clindamycin is chemically unrelated to the macrolides acts on 50s subunit but has a similar mode of action and spectrum. It has greater activity than the macrolides against Gram-negative anaerobes

23. Inhibitors of Nucleic Acid Synthesis

24. 1-Quinolones
The primary target of all quinolones is DNA topoisomerase (gyrase), the enzyme responsible for nicking, supercoiling, and sealing bacterial DNA during replication. Among the fluoroquinolones, ciprofloxacin, norfloxacin, levoafloxacin andofloxacin. .

25. 2-Rifampin
asemisynthetic bactericidal drug derived from Streptomyces . interferes with RNA synthesis.
This agent is active against most Gram-positive bacteria and selected Gram-negative organisms, including Neisseria and Haemophilus
antimycobacterial activity, which includes Mycobacterium tuberculosis.

26. 3-
Metronidazole
 is an antibiotic and antiprotzol medication .

27. Folate Inhibitors

28. Agents that interfere with synthesis of folic acid by bacteria .such as
Sulfonamides.
Trimethoprim-Sulfamethoxazole.