The most common mode of action for antibiotics is the inhibition of cell wall synthesis. Antibiotics that inhibit cell wall synthesis work because of the fact that most eubacteria have peptidoglycan-based cell walls but mammals do not. Growth is prevented by inhibiting peptidoglycan synthesis. Thus these antibiotics only work for actively growing bacteria. The cell wall of new bacteria that grew in the presence of cell-wall-synthesis inhibitors is deprived of peptidoglycan. These bacteria will be subjected to osmotic lysis.In addition, gram-negative bacteria generally are less susceptible to inhibitors of cell wall synthesis than are gram-positive bacteria. In the former cell wall synthesis inhibitors fail to reach the cell wall because they are blocked by the gram-negative outer membrane.Penicillin is the classic example of an inhibitor of cell wall synthesis. Other examples include: ampicillin, bacitracin, carbapenems, cephalosporin, methicillin, oxacillin and vancomycin

1. BYBY
Dr.Dr. SAMINATHAN KAYAROHANAMSAMINATHAN KAYAROHANAM
M.PHARM, M.B.A, PhDM.PHARM, M.B.A, PhD
ANTIBIOTIC
(CELL WALL INHIBITORS )
1
2

2. 2
NUM CONTENT SLIDE
1 OVERVIEW OF PENICILLIN 4
2 DEFINITIONS 5
3 THE SPECTRUM OF ANTIBIOTIC ACTIVITY 6
4 COMMON BACTERIA BY SITE OF INFECTION 7,8
5 DRUG,PRIMARY EFFECTS,SPECTRUM AND SIDE EFFECTS 9
6 GENERAL MECHANISAM OF ANTIBIOTICS 10
7 CLASSIFICATION OF CELL WALL INHIBITORS 11
8 CLASSIFICATION OF PENICILLIN 12-14
9 STRUCTURAL FEATURES OF β-LACTAM ANTIBIOTICS 15
10 MECHANISM OF ACTION OF PENICILLINS 16,17
11 ADVERSE EFFECTS OF PENICILLINS 18,19
12 THERAPEUTIC APPLICATIONS 20-22
13 INTRODUCTION TO CEPHALOSPORINS 23
14 THERAPEUTIC APPLICATIONS OF CEPHALOSPORINS 24

3. 3
LEARNING OUTCOME
1. Able to understand and describe various definition
related to antibiotics
2. Describe the common bacteria, types of infection and
the treatment.
3. Abele to demonstrate the general mechanism of
antibiotics and classification of cell wall inhibitors.
4. Able to describe the penicillin mechanism and
adverse effects.
5. Able to understand the therapeutic application of cell
wall inhibitors.

4. 4
1. OVERVIEW OF PENICILLIN
Antibiotics or Antibacterials are a type of antimicrobial used in
the treatment and prevention of bacterial infection. They may
either kill or inhibit the growth of bacteria.
The penicillin is naturally produced by fungi of the
genus Penicillium.
Penicillin is a common antibiotic, used to treat bacterial infections.
Penicillin was discovered by Scottish scientist Sir Alexander
Flemingin 1928.
Bactericidal An antimicrobial drug that can eradicate an infection in
the absence of host defense mechanisms; kills bacteria.
Bacteriostatic An antimicrobial drug that inhibits microbial growth
but requires host defense mechanisms to eradicate the infection;
does not kill bacteria.
Beta-lactam antibiotics Drugs with structures containing a beta-
lactam ring: includes the penicillins, cephalosporins and
carbapenems. This ring must be intact for antimicrobial action.
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

5. 2. DEFINITIONS
5
Beta-lactamases Bacterial enzymes (penicillinases,
cephalosporinases) that hydrolyze the beta-lactam ring of certain
penicillins and cephalosporins.
Beta-lactam inhibitors Potent inhibitors of some bacterial beta-
lactamases used in combinations to protect hydrolyzable
penicillins from inactivation.
Penicillin-binding proteins (PBPs) Bacterial cytoplasmic
membrane proteins that act as the initial receptors for penicillins
and other beta-lactam antibiotics.
Peptidoglycan Chains of polysaccharides and polypeptides that
are cross-linked to form the bacterial cell wall.
Selective toxicity More toxic to the invader than to the host; a
property of useful antimicrobial drugs.
Transpeptidases Bacterial enzymes involved in the cross-
linking of linear peptidoglycan chains, the final step in cell wall
synthesis.
Con…Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

6. 6
3.THE SPECTRUM OF ANTIBIOTIC ACTIVITY
6Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

7. 7
4.COMMON BACTERIA BY SITE OF INFECTION
Con…Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

8. 8
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

9. 9
5.DRUG,PRIMARY EFFECTS,SPECTRUM AND SIDE EFFECTS
99Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

10. 6.GENERAL MECHANISAM OF ANTIBIOTICS
10
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

11. 11
7.CLASSIFICATION OF CELL WALL INHIBITORS
1111 Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

12. 12
1.Natural Penicillins:
•Aqueous penicillin G
•Penicillin G
•Penicillin VK
2.Beta lacatamse resistant
Penicillins
•Methicillin
•Nafcillin
•Oxacillin
•Cloxacillin
•Dicloxacillin
3. Aminopenicillins
/extended spectrum
•Ampicillin
•Amoxicillin
4. Carboxypenicillins/
antipseudomonal
penicillins /extended
spectrum
•Carcenicillin
•Ticarcillin
5. Ureidopenicillins /
antipseudomonal
penicillins / extended
spectrum
•Mezlocillin
•Piperacillin
6. Penicillins/inhibitor
combination
•Ampicillin/sulbactam
•Ticarcillin/clavulanate
•Piperacillin/tazobactam
•Amoxicillin/clavulanate
8.CLASSIFICATION OF PENICILLIN
Con…Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

13. PHARMACOKINETIC PARAMETERS OF SELECTED
PENICILLINS
13
Con…Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

14. 14
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

15. 15
PENICILLINS
The penicillin's are among the most
widely effective antibiotics and also
the least toxic drugs known, but
increased resistance has limited
their use.
Members of this family differ from
one another in the R substituent
attached to the 6-aminopenicillanic
acid residue.
The nature of this side chain affects
the antimicrobial spectrum, stability
to stomach acid, and susceptibility to
bacterial degradative enzymes (β-
lactamases).
9.STRUCTURAL FEATURES OF Β -LACTAM ANTIBIOTICS
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

16. 10. MECHANISM OF ACTION OF PENICILLINS
16
1.Penicillin-binding proteins:
Penicillins inactivate numerous proteins on the bacterial cell membrane.
These penicillin-binding proteins (PBPs) are bacterial enzymes involved
in the synthesis of the cell wall and in the maintenance of the
morphologic features of the bacterium.
2.Inhibition of transpeptidase:
Penicillins inhibit this transpeptidase-catalyzed reaction, thus hindering
the formation of cross-links essential for cell wall integrity. As a result of
this blockade of cell wall synthesis.
3.Production of autolysins:
Many bacteria, particularly the gram-positive cocci, produce degradative
enzymes (autolysins) that participate in the normal remodeling of the
bacterial cell wall.
Con…
16
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

17. 17
1- Penicillin (or other cell wall synthesis inhibitor) is
added to the growth medium.
2- The cell begins to grow, but is unable to synthesize
new cell wall.
3- cytoplasm covered by plasma membrane begins to
squeeze out through the gap(s) in the cell wall.
4- Cell wall integrity is further violated. The cell
continues to increase in size, but is unable to "pinch
off" the extra cytoplasmic material into two daughter
cells .
5- The loss of the cell wall also causes the cell to lose
control over its shape, Finally, the fact that the cell
disrupts homeostasis, which usually leads to the cell's
death
10. MECHANISM OF ACTION OF PENICILLINS
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

18. 18
11. ADVERSE EFFECTS OF PENICILLINS
Con…Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

19. 19
11. ADVERSE EFFECTS OF PENICILLINS
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

20. 20
12. THERAPEUTIC APPLICATIONS
Con…Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

21. 21
12.THERAPEUTIC APPLICATIONS OF PENICILLIN G.
Con…Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

22. 22
12. ANTIMICROBIAL SPECTRUM OF IMIPENEM
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

23. 13. INTRODUCTION TO CEPHALOSPORINS
23
These β-lactam antibiotics are also fungal products and
have bactericidal activity due to inhibition of
transpeptidase.
The cephalosporins are β-lactam antibiotics that are closely
related both structurally and functionally to the penicillins.
Most cephalosporins are produced semisynthetically by the
chemical attachment of side chains to 7-
aminocephalosporanic acid.
Cephalosporins are acid stable, but many are poorly
absorbed.
Cephalosporins are penicillinase-resistant.
Cephalosporins are broad-spectrum antibacterials.
Cephalosporins are mostly well tolerated.
All can cause allergic reactions, some cause renal injury,
alcohol intolerance, and bleeding (vitamin K antagonism).
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D

24. 24
14.THERAPEUTIC APPLICATIONS OF CEPHALOSPORINS
Dr.K.Saminathan.M.Pharm, M.B.A, Ph.D