Identification of plasmid-mediated tigecycline resistance tet(x4) and New Delhi Metallo-beta-lactamase (NDM) in an Escherichia coli isolate from Canada

Rapid spread of carbapenemase producing Enterobacterales is a global health threat. Tigecycline (TIG) is one of the few last resort therapeutic options available for difficult to treat Gram-negative infections. Resistance by tet(x4) is of particular concern given its association mobile genetic elements. Here we report on TIG-R from a patient recently returned from Pakistan. A tet(x4) gene was found on an IncFII plasmid isolated from an ST410 E.coli co-harbouring NDM-5. The combination of carbepenamse and tet(x4) is concerning.