Cephalosporins

The cephalosporins are broad-spectrum antibiotics, which are closely related to the penicillins. They were originally derived from the fungus Cephalosporium acremonium. Cephalosporins are bactericidal and, like beta-lactam antibiotics such as penicillins, they disrupt the synthesis of the peptidoglycan layer of bacterial cell walls.

Cephalosporins are classified in groups called "generations" by their antibactericidal properties. The first cephalosporins were designated first generation. Later, more extended spectrum cephalosporins were classified as second-generation cephalosporins. Each newer generation of cephalosporins has significantly greater Gram-negative antibactericidal properties than the preceding generation.