Genotypic and Phenotypic Characterization of blaNDM–7-Harboring IncX3 Plasmid in a ST11 Klebsiella pneumoniae Isolated From a Pediatric Patient in China
Chunhong Shao, Yingying Hao, Yong Wang, Meijie Jiang, Yan Jin
Abstract
NDM-7, a variant of New Delhi metallo-beta-lactamases (NDM), has the highest carbapenem-hydrolyzing activity. NDM-7–producing enterobacteria have been reported in many countries. In this study, we reported NDM-7-production in ST11 Klebsiella pneumoniae (K. pneumoniae) isolated from a boy hospitalized in the pediatric intensive care unit of a teaching hospital in China. The isolate exhibited resistance to β-lactam antimicrobials, quinolones, and trimethoprim/sulfamethoxazole and it harbored blaNDM-7, blaCTX-M-15, qnrA, qnrB, and qnrS. The serotype of the isolated K. pneumoniae was assigned as K1, and it contained three virulence genes, including kfuBC, uge, and fim. The blaNDM-7 gene was located on a conjugative IncX3 plasmid designated as pB14NDM-7. This plasmid was fully sequenced and compared with the available blaNDM-7-harboring IncX3 plasmids. pB14NDM-7 contained a conserved genetic context of ISkox3-umuD-IS26-∆Tn125-IS5-∆Tn125-IS3000-∆Tn2. pB14NDM-7 showed 99% nucleotide identity and the same genetic context with three blaNDM-7-harboring IncX3 plasmids obtained from E. coli in China. Our results indicate that IncX3 plasmid may contribute to the prevalence of blaNDM-7 in China. The high prevalence of NDM variants worldwide highlights the critical need for careful monitoring and control of the rapid dissemination of blaNDM.