Outbreak of IMI-1 carbapenemase-producing colistin-resistant Enterobacter cloacae on the French island of Mayotte (Indian Ocean)

Publié le 1 Septembre 2018
Mis à jour le 5 juillet 2019

The spread of carbapenemase-producing Enterobacteriaceae in the Southwest Indian Ocean islands is poorly known. Here we describe an outbreak of colistin-resistant Enterobacter cloacae harbouring blaIMI-1 in the French overseas department of Mayotte. Between October 2015 and January 2017, all isolates of imipenem-non-susceptible E. cloacae at Mayotte Medical Center and University Hospital of Reunion Island were screened for carbapenemase production. Positive isolates were typed by pulsed-field gel electrophoresis and whole-genome sequencing (WGS)-based multilocus sequence typing (MLST), and all β-lactamase genes were identified by PCR and sequencing. Resistance profiles were determined by agar diffusion and Etest. Genetic support of the blaIMI-1 gene was determined by WGS. A total of 18 E. cloacae isolates harbouring blaIMI-1 were detected in 17 patients from Mayotte. Pulsed-field gel electrophoresis (PFGE) analysis showed 16 of the 18 strains to be clonally related and belonging to ST820. Based on clinical data, this outbreak most likely had a community origin. The blaIMI-1 gene in the 18 isolates was carried by a new variant of an integrative mobile element involving the Xer recombinases, called EcloIMEX-8. The mcr-1-mcr-5 genes were absent from the collection. The isolates belonged to E. cloacae cluster XI, known to be colistin heteroresistant. Here we report the first outbreak of IMI-1-producing Enterobacteriaceae. IMI-1-producers may be underdetected in microbiology laboratories because of their unusual antimicrobial resistance profile (resistant to imipenem but with intermediate resistance to ertapenem and susceptible to extended-spectrum cephalosporins) and the absence of blaIMI-1 in the panel of genes targeted by molecular diagnostic kits.

Auteur : Miltgen Guillaume, Bonnin Rémy A, Avril Catherine, Benoit-Cattin Thierry, Martak Daniel, Leclaire Alexandre, Traversier Nicolas, Roquebert Bénédicte, Jaffar-Bandjee Marie-Christine, Lugagne Nathalie, Filleul Laurent, Subiros Marion, de Montera Anne-Marie, Cholley Pascal, Thouverez Michelle, Dortet Laurent, Bertrand Xavier, Naas Thierry, Hocquet Didier, Belmonte Olivier
International Journal of Antimicrobial Agents, 2018, vol. 52, n°. 3, p. 416-420