KPC-2-encoding plasmids from escherichia coli and Klebsiella pneumoniae in Taiwan

Abstract

Objectives: Two plasmids carrying blaKPC-2 isolated from carbapenem-resistant Escherichia coli (CR-EC) and carbapenem-resistant Klebsiella pneumoniae (CR-KP), respectively, were completely sequenced. The CR-KP strain was selected from an outbreak in 2012, and the CR-EC strain was the first blaKPC-2-carrying E. coli identified in the same carbapenem resistance monitoring programme in Taiwan. Methods: Antimicrobial susceptibility tests, multilocus sequence typing (MLST) and the conjugal transfer of plasmids were performed. Complete sequencing of the plasmids was performed using a shotgun approach. Results: The CR-EC and CR-KP strains in this study were determined to be ST410 and ST11, respectively, by MLST. From CR-EC, we identified a 145 kb conjugative plasmid that carries blaKPC-2, blaCMY-2, blaCTX-M-3 and blaTEM-1. The plasmid is a chimera composed of three regions related to IncI, IncN and RepFIC replicons. From CR-KP, we identified an 86.5 kb plasmid, pKPC-LK30, which carries blaKPC-2 and blaSHV-11. The plasmid is very similar to two blaKPC-2-carrying IncFIIK plasmids, but lacks one of the replication origins and cannot conjugate. Conclusions: The differences in cross-species transferability of the two plasmids can be explained by genetic differences between their backbones and could have resulted in the confined blaKPC-2-carrying CR-KP outbreak in Taiwan. Plasmid pKPC-LKEc is the first blaKPC-2-carrying plasmid identified from CR-EC in Taiwan. With relatively high transferability it should be closely monitored. © The Author 2013. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.