Broad spectrum beta-lactamase which hydrolyzes penicillins, as well as cephalosporins except cephamycins. Also hydrolyzes aztreonam, but not imipenem. Confers highly resistance to ceftazidime, cefotaxime, aztreonam and piperacillin. a beta-lactam + H2O = a substituted beta-amino acid Inhibited 16-fold better by the beta-lactamase inhibitor clavulanic acid than by tazobactam. Belongs to the class-A beta-lactamase family.