Chromosome-Encoded Ambler Class A β-Lactamase of <i>Kluyvera georgiana</i> , a Probable Progenitor of a Subgroup of CTX-M Extended-Spectrum β-Lactamases

Abstract

A chromosome-encoded beta-lactamase gene, cloned and expressed in Escherichia coli from Kluyvera georgiana reference strain CUETM 4246-74 (DSM 9408), encoded the extended-spectrum beta-lactamase KLUG-1, which shared 99% amino acid identity with the plasmid-mediated beta-lactamase CTX-M-8. This work provides further evidence that Kluyvera spp. may be the progenitor(s) of CTX-M-type beta-lactamases.