A novel blaCTX-M-6Harboring IncHI2 plasmid pE648CTX-M-65 isolated from a clinical extensively-drug-resistant Escherichia coliST648
Background: An ESBL, carbapenemase- and MCR-1-producing Escherichia coli ST648 strain was isolated from the urine sample of a patient in a Chinese tertiary hospital in 2016.
Methods: The strain was fully sequenced by GridION X5 platform of Oxford Nanopore Technology.
Results: The sequence analysis showed that the extended-spectrum β-lactamases CTX-M-65 and OXA-1, the carbapenemase NDM-5, the MCR-1 were encoded, respectively, by three different resistance plasmids. The pE648CTX-M-65-carrying blaCTX-M-65 was a novel conjugative plasmid belonging to IncHI2 type; except for the blaCTX-M-65, it also carried resistance genes ble, floR, sul1, aph(4)-Ia, aac(3)-VI, aac(6ʹ)-II, blaOXA-1, catB, arr3 and tetA. Besides, an IncX4 plasmid pE648MCR-1-carrying mcr-1 and an IncX3 plasmid pE648NDM-5-carrying blaNDM-5 were also identified.
Conclusion: The three transferable resistance plasmids coexisting in the E. coli ST648 isolate indicated the high risk to disseminate the extensively-drug-resistance among Enterobacteriaceae.