Cefdinir

Five-member thiazolidine rings that make up penicillins are replaced in cephalosporins by a six-member dihydrothiazine ring, conferring greater bactericidal activity. This 6-member ring enables cefdinir and other cephalosporins to resist inactivation by certain bacterial enzymes.

With a mechanism similar to other beta-lactam antibiotics, the bactericidal activity of cefdinir is caused by the inhibition of cell wall synthesis via binding to penicillin-binding proteins (PBPs). Cefdinir, like other cephalosporins, penetrates the bacterial cell wall, combats inactivation by beta-lactamase enzymes, and inactivates penicillin-binding proteins. This interferes with the final step of transpeptidation in cell walls, eventually leading to cell lysis, which eventually leads to the death of bacteria that are susceptible to this drug. Cefdinir has shown affinity to penicillin protein binding proteins 2 and 3. It has also been shown to inhibit transpeptidase enzymes of various bacteria, which may play a role in its bactericidal action. One in vitro study suggests that cefdinir inhibits myeloperoxidase release extracellularly. The impact of this potential drug target in relation to its mechanism of action is unknown.