Reduced Susceptibility to Cefepime among Escherichia coli Clinical Isolates Producing Novel Variants of CMY-2 β-Lactamase

Here we describe three Escherichia coli clinical isolates with reduced susceptibility to cefepime. Sequencing of the bla(CMY) genes revealed two novel variants (CMY-33 and -44) with two- to four-amino-acid deletions in the H-10 helix. The deletions were responsible for 12- to 24-fold increases in the MICs of cefepime.