First Identification of Novel NDM Carbapenemase, NDM-7, in Escherichia coli in France

BACKGROUND: The NDM-1 carbapenemase has been identified in 2008 in Enterobacteriaceae. Since then, several reports have emphasized its rapid dissemination throughout the world. The spread of NDM carbapenemases involve several bla (NDM) gene variants associated with various plasmids among several Gram negative species. METHODOLOGY: A multidrug-resistant E. coli isolate recovered from urine of a patient who had travelled to Burma has been characterized genetically and biochemically. PRINCIPAL FINDINGS: E. coli COU was resistant to all antibiotics tested except amikacin, tigecycline, fosfomycin, and chloramphenicol. Analysis of the antibiotic resistance traits identified a metallo-ß-lactamase, a novel NDM variant, NDM-7. It differs from NDM-4 by a single amino acid substitution sharing an identical extended spectrum profile towards carbapenems. The bla (NDM-7) gene was located on an untypeable conjugative plasmid and associated with a close genetic background similar to those described among the bla (NDM-1) genes. The isolate also harbours bla (CTXM-15) and bla (OXA-1) genes and belonged to ST167. SIGNIFICANCE: This study highlights that spread of NDM producers correspond to spread of multiple bla (NDM) genes and clones and therefore will be difficult to control.