CMY-20, a novel AmpC-type β-lactamase from South African clinical Escherichia coli isolates

In this study, we report the presence of a novel plasmid-mediated AmpC-type β-lactamase that was isolated from 3 clinical Escherichia coli isolates at a tertiary teaching hospital in Durban, South Africa. The nucleotide sequence of the genes encoding this novel β-lactamase was found to be >94% identical to the nucleotide sequences of the plasmid-mediated AmpC-type β-lactamases originating from Citrobacter freundii. This enzyme differed from CMY-2 by 3 amino acid substitutions and was designated CMY-20.