Investigation of carbapenem-resistant Klebsiella pneumoniae in Taiwan revealed strains co-harbouring bla and bla and a novel plasmid co-carrying bla and bla.

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 bla-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 bla alone; however, 12% (17/137) carried bla+bla and these strains showed high resistance to imipenem and meropenem. Strains carrying bla+bla predominantly belonged to KL51 (n=15), followed by KL64 (n=1) and KL47 (n=1). Whole-genome sequencing of one KL51 strain indicated that bla and bla are carried on two different plasmids. PCR was performed using specific primers located in these plasmids, and all bla+bla-encoding strains except the KL64 strain were considered to carry the two abovementioned plasmids. Genome analysis for the KL64 strain revealed that bla and bla are encoded in one plasmid. Notably, the KL51 bla plasmid shared high sequence similarity with the KL64 bla+bla plasmid, except the KL64 plasmid comprised a 15,040-bp insertion encoding bla. The data revealed KL51 as a predominant KL type carrying bla+bla, and identified a novel plasmid carrying bla+bla, highlighting the spread of specific plasmids and clones of CRKP in Taiwan.