Cephalosporins a Class of Beta Lactam Antibiotics and Monobactam antibiotics.pptx

Antibiotics are one of the most powerful tools in modern medicine, used to combat bacterial infections that, if left untreated, can be life-threatening. Among the broad range of antibiotics, Cephalosporins and Monobactams play significant roles in managing a variety of bacterial infections. Both are members of the beta-lactam antibiotic class, meaning they all have a similar core structure, including a beta-lactam ring that is essential for their antibacterial activity.

Cephalosporins are broad-spectrum antibiotics commonly used for treating infections caused by a variety of bacteria. They were initially derived from the Acremonium fungus and have undergone extensive modifications, which have led to the development of several generations of cephalosporins with increased effectiveness against different bacterial pathogens.

On the other hand, Monobactams, which have a monocyclic structure unlike the bicyclic structure of other beta-lactams, are used to treat specific Gram-negative bacterial infections. Their narrow spectrum of action makes them especially useful in cases where other antibiotics, such as penicillin and cephalosporins, might not be suitable due to allergies or resistance. The most well-known monobactam is Aztreonam, which is often used to treat infections caused by Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli.

Classification of Cephalosporins
Cephalosporins are classified into five generations, each with a unique set of characteristics and antibacterial coverage. he classification is based on their activity against Gram-positive and Gram-negative bacteria, as well as their resistance to beta-lactamase enzymes.
Mechanism of Action of Cephalosporins
The primary mechanism by which Cephalosporins exert their antibacterial effect is through the inhibition of bacterial cell wall synthesis. The cell wall is essential for the structural integrity of bacterial cells, and its disruption leads to bacterial lysis.
Here’s how cephalosporins work:

Binding to Penicillin-Binding Proteins (PBPs): Cephalosporins bind to PBPs, which are enzymes involved in the final stages of cell wall synthesis. PBPs help in the cross-linking of peptidoglycan layers, which are essential for the structural strength of the bacterial cell wall.

Inhibition of Peptidoglycan Cross-Linking: By binding to PBPs, cephalosporins inhibit the formation of cross-links between peptidoglycan chains in the cell wall, which weakens the structure.

Bacterial Cell Lysis: The weakened cell wall leads to increased susceptibility to osmotic pressure, causing the bacterial cell to burst and die.

Monobactam Antibiotics
Monobactams are a class of synthetic antibiotics that feature a monocyclic beta-lactam ring, unlike the bicircular structure of cephalosporins and penicillins. The most widely used monobactam is Aztreonam, which has significant activity against Gram-negative bacteria.
The monocyclic structure of monobactams makes them distinct from other beta-lactam

1. Cephalosporins a class of beta-lactam antibiotics  Samruddhi Khonde Asst. Professor P. R. Patil Institute of Pharmacy, Talegaon (S.P.)

2. Cephalosporins a class of beta-lactam antibiotics  9/3/20XX Cephalosporins 2 Cephalosporins are a second major class of beta-lactam antibiotics that are widely utilized in clinical practice to treat a variety of bacterial infections. They are derived from the fungus * Cephalosporium acremonium * and are known for their ability to inhibit bacterial cell wall synthesis, which is crucial for bacterial survival. Cephalosporins are categorized into generations (first through fifth), with each generation exhibiting different spectra of activity against Gram-positive and Gram-negative bacteria. The first generation is primarily effective against Gram-positive organisms, while later generations have broader activity, including enhanced effectiveness against resistant strains.

3. 9/3/20XX Presentation Title 3 Cephalosporins are antibiotics that share the structure of a beta-lactam ring linked to a dihydrothiazine ring. The antibacterial action is attributed to the beta-lactam ring, while the dihydrothiazine ring offers molecular stability. Structure of Cephalosporins Cephalosporins’ structures may be altered by adding different chemical groups to the molecule, resulting in distinct generations of them with variable activity spectrum and pharmacokinetic features.

4. 9/3/20XX Classification of Cephalosporin 4

5. Mechanism of Action Cephalosporins, beta-lactam antibiotics, have a beta-lactam ring that is crucial for the antibiotic's activity because it targets bacterial cells by disrupting cell wall synthesis. They enter the bacterial cell through passive diffusion. Within the bacterial cell wall, cephalosporins bind to specific enzymes known as penicillin-binding proteins (PBPs). PBPs are crucial for cross-linking peptidoglycan chains, a key structural component of bacterial cell walls. Cephalosporins inhibit transpeptidation catalyzed by PBPs. Transpeptidation is a step in the synthesis of the peptidoglycan layer where the peptide side chains are linked, providing strength and stability to the bacterial cell wall. This inhibition by cephalosporins activates bacterial autolytic enzymes, causing the degradation of the existing peptidoglycan and weakening the cell wall. The resulting structural instability leads to cell lysis and bacterial death. 9/3/20XX Presentation Title 5

6. Generations : Cephalosporins are categorized into generations (first through fifth), with each generation having a different spectrum of activity: First Generation : Effective against Gram-positive bacteria (e.g., cefazolin). Second Generation : Broader spectrum including some Gram-negative bacteria (e.g., cefuroxime). Third Generation : Increased activity against Gram-negative bacteria and some resistance to beta-lactamases (e.g., ceftriaxone). Fourth Generation : Broad-spectrum activity, including resistant strains (e.g., cefepime). Fifth Generation : Effective against MRSA and other resistant organisms (e.g., ceftaroline ). 9/3/20XX Presentation Title 6

7. 9/3/20XX The Structure-Activity Relationship (SAR) of Cephalosporins 7 The Structure-Activity Relationship (SAR) of Cephalosporins

8. The Structure-Activity Relationship (SAR) of Cephalosporins The Structure-Activity Relationship (SAR) of cephalosporins involves understanding how modifications to their chemical structure affect their antibacterial activity, spectrum of activity, and pharmacokinetic properties. Key points include: Beta-Lactam Ring : The presence of the beta-lactam ring is essential for antibacterial activity, as it is crucial for inhibiting bacterial cell wall synthesis. Dihydrothiazine Ring : The structure of the dihydrothiazine ring influences the stability of the antibiotic and its ability to resist hydrolysis by beta-lactamases. Side Chains : Variations in the side chains attached to the beta-lactam ring can enhance activity against specific bacteria, improve pharmacokinetics, and reduce susceptibility to enzymatic degradation. Generation Differences : The first-generation cephalosporins are generally more effective against Gram-positive bacteria, while later generations (second, third, and fourth) have increased activity against Gram-negative bacteria and improved resistance to beta-lactamases. These structural modifications are critical for developing cephalosporins with desired therapeutic profiles and efficacy against various bacterial infections . 9/3/20XX 8

9. 9/3/20XX Presentation Title 9 Structures of some Drugs from first to fourth Generation of Cephalosporins

10. Monobactam a class of beta-lactam antibiotics  Samruddhi Khonde Asst. Professor P. R. Patil Institute Of Pharmacy, Talegaon (S.P.)

11. Monobactam a class of beta-lactam antibiotics  Monobactams are a class of beta-lactam antibiotics characterized by their unique monocyclic beta-lactam structure . The most well-known monobactam is aztreonam . Here are some key details: Structure : Monobactams contain a single beta-lactam ring , which distinguishes them from other beta-lactam antibiotics that typically have a bicyclic structure. This unique structure contributes to their specific antibacterial properties. 9/3/20XX Presentation Title 11

12. Monobactam a class of beta-lactam antibiotics  9/3/20XX Presentation Title 12 Mechanism of Action : Like other beta-lactams, monobactams inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). This action disrupts the cross-linking of peptidoglycan layers in the bacterial cell wall, leading to cell lysis and death. Resistance to Beta-Lactamases : Monobactams are relatively resistant to certain types of beta-lactamases, particularly those produced by Gram-negative bacteria, which makes them useful in treating infections caused by resistant strains.

13. Thank You 9/3/20XX Presentation Title 13