Lifeng Chen,1,* Ruishan Liu,2,3,* Haowei Ye,2 Jiajie Qian,4 Danfeng Lou5 

1Department of Clinical Engineering and Materials Supplies, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 2State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People’s Republic of China; 3Jinan Microecological Biomedicine, Shandong Laboratory, Jinan, People’s Republic of China; 4Department of Gastrointestinal Surgery, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 5Department of Infectious Diseases, Shulan (Hangzhou) Hospital, Hangzhou, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Danfeng Lou, Department of Infectious Diseases, Shulan (Hangzhou) Hospital, No. 848 Dongxin Road, Hangzhou, People’s Republic of China, Email loudanfeng@126.com Jiajie Qian, Department of Gastrointestinal Surgery, The First Affiliated Hospital, College of Medicine Zhejiang University, No. 79 Qingchun Road, Hangzhou, People’s Republic of China, Email 1202058@zju.edu.cn

Abstract: The global dissemination of carbapenem-resistant Enterobacteriaceae poses a significant threat to public health. In this study, we identified two clinical Klebsiella isolates, K. quasipneumoniae ACESH02628 and K. pneumoniae ACESH02857, harboring the blaNDM-5 gene in China. Both strains exhibited multidrug resistance, including reduced susceptibility to carbapenems, and carried transferable NDM-5-bearing plasmids. Specifically, S1-pulsed-field gel electrophoresis (PFGE), southern blotting, and whole-genome sequencing revealed that ACESH02628 contained an IncHI2/IncHI2A-type plasmid, while ACESH02857 carried an IncX3-type plasmid, both associated with the regional spread of NDM-5. Comparative analyses showed high genetic similarity with previously reported NDM-5 plasmids from Salmonella enterica and Escherichia coli in China, underscoring the ease of horizontal transfer and potential for broader dissemination. Our findings highlight the emergence of NDM-5-producing K. quasipneumoniae of clinical origin and reinforce the need for vigilant surveillance and infection control measures to curb the proliferation of these highly resistant pathogens.

Keywords: blaNDM-5, Klebsiella spp., carbapenem-resistant, whole-genome sequencing