TEM-28 from an Escherichia coli clinical isolate is a member of the his-164 family of TEM-1 extended-spectrum β-lactamases

Abstract

TEM-28 (pI 6.1), expressed by an Escherichia coli clinical isolate, is a novel β-lactamase which hydrolyzed ceftazidime, cefotaxime, and aztreonam with rates of 25, 1.1, and 5.6, respectively, relative to that for benzylpenicillin (100). The nucleotide sequence of blaTEM-28 differed from that of blaTEM-1 by two base changes, resulting in amino acid substitutions of Arg-164 to His and Glu-240 to Lys.