Biochemical characterization of TEM-92 extended-spectrum beta-lactamase, a protein differing from TEM-52 in the signal peptide.

A bla(TEM-92) gene was cloned from a Proteus mirabilis isolate and expressed in Escherichia coli. Production of the enzyme caused reduction of susceptibility to penicillins and narrow- to expanded-spectrum cephalosporins but not to moxalactam and cephamycins. Determination of kinetic parameters with the purified enzyme revealed hydrolysis of expanded-spectrum cephalosporins, while cephamycins, moxalactam, and aztreonam were very poorly or not hydrolyzed. Clavulanate and penicillanic acid sulfones acylated TEM-92 slowly, and deacylation occurred at measurable rates.