Investigation of carbapenem-resistant Klebsiella pneumoniae in Taiwan revealed strains co-harbouring blaNDM and blaOXA-48-like and a novel plasmid co-carrying blaNDM-1 and blaOXA-181

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) is related to the transmission of carbapenemase genes. Strains carrying more than one carbapenemase with a broadened spectrum of antibiotic resistance have been detected, which is concerning. Although blaKPC-encoding ST11-KL47/KL64 strains are dominant, other clones are emerging. This study investigated 137 CRKP from patients' blood samples in Taiwan. Polymerase chain reaction (PCR) was used to identify carbapenemase genes and capsular (KL) types. Most strains (56%, 77/137) possessed blaKPC alone; however, 12% (17/137) carried blaNDM+blaOXA-48-like and these strains showed high resistance to imipenem and meropenem. Strains carrying blaNDM+blaOXA-48-like predominantly belonged to KL51 (n=15), followed by KL64 (n=1) and KL47 (n=1). Whole-genome sequencing of one KL51 strain indicated that blaNDM-4 and blaOXA-181 are carried on two different plasmids. PCR was performed using specific primers located in these plasmids, and all blaNDM+blaOXA-48-like-encoding strains except the KL64 strain were considered to carry the two abovementioned plasmids. Genome analysis for the KL64 strain revealed that blaNDM-1 and blaOXA-181 are encoded in one plasmid. Notably, the KL51 blaOXA-181 plasmid shared high sequence similarity with the KL64 blaNDM-1+blaOXA-181 plasmid, except the KL64 plasmid comprised a 15,040-bp insertion encoding blaNDM-1. The data revealed KL51 as a predominant KL type carrying blaNDM-4+blaOXA-181, and identified a novel plasmid carrying blaNDM-1+blaOXA-181, highlighting the spread of specific plasmids and clones of CRKP in Taiwan.