Host-Specific Patterns of Genetic Diversity among IncI1-Iγ and IncK Plasmids Encoding CMY-2 β-Lactamase in Escherichia coli Isolates from Humans, Poultry Meat, Poultry, and Dogs in Denmark.

Unlabelled: CMY-2 is the most common plasmid-mediated AmpC β-lactamase in Escherichia coli isolates of human and animal origin. The aim of this study was to elucidate the epidemiology of CMY-2-producing E. coli in Denmark.

High diversity of plasmids harbouring blaCMY-2 among clinical Escherichia coli isolates from humans and companion animals in the upper Midwestern USA.

Objectives: To determine the population structure and genetic relatedness of plasmids encoding CMY-2 β-lactamase in clinical Escherichia coli from humans and companion animals within a defined geographical area.

Methods: In total, 42 human and 73 companion animal isolates displaying an AmpC phenotype were isolated at a regional diagnostic reference laboratory in the upper Midwestern USA during 2009-11. Following PCR screening for transferable AmpC genes and plasmid transformation, blaCMY-2-positive plasmids were characterized by S1 nuclease PFGE, PCR-based replicon typing, antimicrobial susceptibility testing of transformants, conjugation experiments, plasmid multilocus sequence typing and restriction fragment length polymorphism.