کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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3358503 | 1591777 | 2014 | 6 صفحه PDF | دانلود رایگان |
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. IS1294–ISEcp1 complex or ISEcp1 that was truncated by IS1294 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.
Journal: International Journal of Antimicrobial Agents - Volume 44, Issue 3, September 2014, Pages 203–208