Find the word definition

Wiktionary
carbacephem

n. Any of a class of synthetic antibiotics based on the structure of cephalosporin, a cephem, that prevent bacterial cell division by inhibiting cell wall synthesis.

Wikipedia
Carbacephem

Carbacephems are a class of synthetic antibiotics, based on the structure of cephalosporin, a cephem. Carbacephems are similar to cephems, but with a carbon substituted for the sulfur.

It prevents bacterial cell division by inhibiting cell wall synthesis.