The mechanism of action of cephalosporin is:
Ans: A (Interferes with cell wall synthesis) Ref: Goodman & Gilmans The Pharmacological Basis of Therapeutics, 12th ed, 2011. Pg 1479, 1493: Basic and Clinical Pharmacology by Katzung, 2012, 12th ed, Pg 792Explanation:Cephalosporin inhibits bacterial cell wall synthesis.Its mechanism of action is similar to penicillin as both are beta lactams.Bacterial ceil wall plays a major role in the growth and development of bacteria.Peptidoglycan. a component of bacterial cell wall owing to its cross-linked structure offers strength to the cell wall.Peptidoglycan is composed of N-acetyl- glucosamine and N-acetylmuramic acid with cross-linking.A five amino acid peptide known as pentapeptide is linked to N-acetylmuramic acid and this peptide terminates as D-alanyl-D- alanine.Penicillin Binding Protein (PBP) removes terminal alanine from D-alanyl -D-alanine and forms cross link with the adjacent peptide, thus enhancing cell wall rigidity.Beta lactam antibiotics are structurally similar to D-alanyl -D-alanine, and hence covalently bind to PBP, resulting in inhibition of transpeptidation reaction w hich is essential for the removal of D-alanine from D-alanyl-D- alanine.As peptidoglycan synthesis is inhibited by cephalosporins as any other beta lactams, the bacterial cell dies. However cell death is maximum when the cells are actively growing and synthesizing cell wall.
Interferes with cell wall synthesis
Inhibition ol DNA gyrase
Inhibition of protein synthesis
Inhibition of DMA polymerase
Penicillin & Cephalosporin