Expansive spread of IncI1 plasmids carrying blaCMY-2 amongst Escherichia coli

• Published in: International journal of antimicrobial agents 2014-09, Vol.44 (3), p.203-208
• Main Authors: Sidjabat, Hanna E, Seah, Kwee Yong, Coleman, Lyndall, Sartor, Anna, Derrington, Petra, Heney, Claire, Faoagali, Joan, Nimmo, Graeme R, Paterson, David L
• Format: Article
• Language: English
• Subjects: beta-Lactamases - genetics; beta-Lactamases - secretion; CMY-2; DNA Transposable Elements; Escherichia coli - classification; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli Infections - microbiology; Gene Order; Gene Transfer, Horizontal; Humans; IncI1 plasmid; Infectious Disease; Molecular Typing; Phylogeny; Plasmid analysis; Plasmids - analysis; Sequence Analysis, DNA; Synteny; Urinary Tract Infections - microbiology
• ISSN: 0924-8579; 1872-7913
• DOI: 10.1016/j.ijantimicag.2014.04.016

Abstract Escherichia coli is a leading cause of urinary tract infections. One of the most common antibiotic classes used to treat such infections is the β-lactams, including cephalosporins. Resistance to the third-generation cephalosporins can be caused by production of extended-spectrum β-lactamases (ESBLs) or plasmid-mediated AmpC β-lactamases. The most commonly reported AmpC β-lactamase in E. coli is CMY-2. Plasmid-mediated CMY-2 has been frequently reported in E. coli and Salmonella sp. from food-producing animals. This study aimed to elucidate the molecular characteristics of clinical E. coli isolates carrying plasmids encoding CMY-2. A total of 67 CMY-2-producing E. coli were characterised by clonal analysis and phylogenetic typing. Characterisation of the plasmids carrying blaCMY-2 included replicon typing, plasmid profiling, plasmid transferability and sequencing of the blaCMY-2 genetic environment. As a result, E. coli producing CMY-2 was found to be highly polyclonal. The majority of CMY-2-producing E. coli belonged to phylogenetic group D. IncI1 plasmids were predominant among those carrying blaCMY-2 (96%). Restriction analysis revealed a single IncI1 plasmid carrying blaCMY-2 to be predominant and present in different clones of E. coli . IS 1294– IS Ecp1 complex or IS Ecp1 that was truncated by IS 1294 was the predominant insertion sequence upstream of blaCMY-2 . The homogeneous genetic environment of blaCMY-2 observed among different strains of E. coli strongly suggests horizontal transfer of this IncI1, blaCMY-2 -carrying plasmid. In summary, horizontal plasmid transfer plays a major role in the spread of blaCMY-2 in E. coli.