Detection of multiple cephalosporin-resistant Escherichia coli from a cattle fecal sample in Great Britain

Abstract

We describe the isolation of multiple cephalosporin-resistant Escherichia coli from cattle feces collected from animals at slaughter in Great Britain. Six E. coli strains were isolated with distinct XbaI pulsed-field gel electrophoresis (PFGE) profiles and different mechanisms of cephalosporin resistance from a single fecal sample. Two of these strains were found to contain conjugative plasmids conferring resistance to extended-spectrum cephalosporins that were indistinguishable from each other by restriction endonuclease digestion. Sequence analysis of the plasmid-encoded ampC showed that they were identical to bla(CMY-2), previously described in multiple-drug-resistant Salmonella and E. coli from animals in other parts of the world. DNA sequence analysis of the chromosomal ampC promoter regions for three cephalosporin-resistant strains lacking CMY-2 was determined. Several mutations were detected in the isolates tested including changes at positions -42 and -32, which are known to increase promoter strength. This report represents the first isolation of E. coli containing bla(CMY-2) from cattle in Great Britain, and, also to our knowledge, the first demonstration of multiple cephalosporin-resistant strains in a single animal.