Det bliver dog inaktiveret af beta- laktamaser, som effektivt kan hydrolysere cefalosporiner, således mange af beta- laktamaserne med udvidet spektrum og kromosomale cefalosporinaser, som enzymer af AmpC- typen.
However, it is inactivated by beta-lactamases that can efficiently hydrolyse cephalosporins, such as many of the extended-spectrum beta-lactamases and chromosomal cephalosporinases, such as AmpC type enzymes.