Diversity of carbapenemase-producing Escherichia coli isolates in France in 2012-2013

Abstract

With the dissemination of carbapenemase-producing Enterobacteriaceae (CPE) strains worldwide, carbapenem-hydrolyzing enzymes are increasingly reported among isolates of Escherichia coli, the first hospital and community-acquired opportunistic pathogen. Here, we have performed an epidemiological survey of carbapenemase-producing E. coli (CP-Ec) isolates received at the French National Reference Centre (F-NRC) in 2012 and 2013. Antimicrobial susceptibilities for last-resort antibiotics and antimicrobial compounds commonly used to treat urinary tract infections were determined by broth microdilution. Clonal relationship was assessed using repetitive sequence-based PCR (rep-PCR) and multilocus sequence typing (MLST). From this collection of 140 carbapenemase-producing E. coli isolates, 74% produced an OXA-48-like carbapenemase and 21% produced an NDM carbapenemase. A link with a foreign country was suspected for 37% of infected/colonized patients. Most of the isolates were from screening (56%) and from urine samples (26%). Colistin, fosfomycin, and nitrofurantoin possessed the most consistent activity, with 100%, 95%, and 96% isolates susceptible, respectively. A wide diversity of carbapenemase-producing E. coli isolates has been found (50 different sequence types [STs]). The most prevalent clones were (i) E. coli sequence type 38 (ST38) producing OXA-48 (n 21), a clone linked to Turkey and North African countries, (ii) E. coli ST-90 producing OXA-204 (n 9), which was responsible for an outbreak related to a contaminated duodenoscope, and (iii) E. coli ST-410 producing OXA-181 (n 5), which was recovered from patients of different geographical origins. These specific clones might be considered high-risk clones for the dissemination of carbapenemases in E. coli. The wide diversity of STs, combined with the increasing number of CP-Ec isolates received by the F-NRC, suggests a likely dissemination of CP-Ec isolates in the community.