Characterization of blactx-M incfii plasmids and clones of Escherichia coli from pets in France

Abstract

Objectives: To characterize blaCTX-M IncFII plasmids and clones of Escherichia coli from cats and dogs and to compare them with blaCTX-M IncFII plasmids reported in humans. Methods: From December 2006 to April 2010, 518 E. coli isolates from clinical infections in cats and dogs were screened for extended-spectrum b-lactamase (ESBL) production. Antimicrobial susceptibility was performed by disc diffusion and resistance genes were identified by PCR and sequencing. Plasmids were characterized using PCR-based replicon typing and sub-typing schemes, restriction fragment length polymorphism analysis, S1-PFGE and Southern hybridization. Isolates were characterized by PFGE, phylogenetic grouping, O25b typing and multilocus sequence typing. Results: Nineteen E. coli isolates (3.7%) produced ESBLs, of which 14 (74%) carried blaCTX-M IncFII plasmids. The blaCTX-M-15 gene was predominant and located on F31:A4:B1, F36:A4:B1 or F36:A1:B20 plasmids, abundantly reported in humans. The blaCTX-M-15 F22:A1:B20 or F2:A2:B20 plasmids were also found. Different sequence types (STs) were identified, such as ST10, ST410, ST359, ST617 and ST224. Only one E. coli isolate belonged to the ST131 E. coli clone and carried a blaCTX-M-14 F2:A2:B20 plasmid. Conclusions: This is the firstknownextensive studyonESBL-producing E. coli isolates frompets in France.The ST131 clonewas rare.However, the predominance of human-like blaCTX-M-15 IncFII plasmids suggests exchanges of these plasmids with the human reservoir. © The Author 2013. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.