Cloning and sequencing of the β-lactamase gene and surrounding DNA sequences ofCitrobacter braakii,Citrobacter murliniae,Citrobacter werkmanii,Escherichia fergusoniiandEnterobacter cancerogenus

Abstract
To further identify the origins of plasmid-mediated cephalosporinases that are currently spreading worldwide, the chromosomal β-lactamase genes of Ci