Genetic Characterization of an ST5571 Hypervirulent Klebsiella pneumoniae Strain Co-Producing NDM-1, MCR-1, and OXA-10 Causing Bacteremia

Xiaolong Ma,1,* Xiaodong Lv,1,* Sihan Feng,1 Ruishan Liu,2,3 Hao Fu,2 Feng Gao,1 Hao Xu2 1Department of Respiratory Medicine, the First Hospital of Jiaxing (Affiliated Hospital of Jiaxing University), Jiaxing, People’s Republic of China; 2Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 3Department of Laboratory Medicine, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, People’s Republic of China*These authors have contributed equally to this workCorrespondence: Feng Gao, Department of Respiratory Medicine, the First Hospital of Jiaxing (Affiliated Hospital of Jiaxing University), No. 1882 South Zhonghuan Road, Jiaxing, 314000, People’s Republic of China, Tel +86 573 825 198 70, Fax +86 573 820 830 06, Email guti-gf@163.com Hao Xu, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79 Qing chun Road, Hangzhou, 310003, People’s Republic of China, Tel +86 571 872 364 23, Fax +86 571 872 364 21, Email xuhao0523@zju.edu.cnPurpose: To investigate the phenotypic and genomic characteristics of the multi-drug resistant and hypervirulent Klebsiella pneumoniae strain recovered from bacteremia.Methods: Antimicrobial susceptibility testing (AST) was performed by the microdilution method. Antimicrobial resistance genes, virulence-associated genes, multilocus sequence typing (MLST), and plasmid replicon were characterized by next-generation sequencing (NGS) and nanopore sequencing. S1 nuclease-pulsed field gel electrophoresis (S1-PFGE) and Southern blotting were performed to characterize the plasmid profile.Results: The hypervirulent colistin- and carbapenem-resistant K. pneumoniae strain DY2009 was identified as ST5571, co-carrying mcr-1, blaNDM-1, and blaOXA-10. In silico analysis found that it was K2 serotype. AST results revealed that DY2009 was resistant to carbapenems, cephalosporins, ciprofloxacin, chloramphenicol, and colistin but remained susceptible to aztreonam, gentamicin, amikacin, and tigecycline. Through the whole-genome analysis, a variety of virulence determinants were identified, including rmpA. Plasmid analysis confirmed that the mcr-1 and blaNDM-1 gene harbored a ∼ 33 kb IncX4 plasmid and a ∼ 44 kb IncX3 plasmid. In contrast, blaOXA-10 was encoded by chromosome.Conclusion: To the best of our knowledge, we first report the clinical hypervirulent K. pneumoniae isolate co-producing MCR-1, NDM-1, and OXA-10 causing bacteremia. We found that mcr-1 and blaNDM-1 genes were located on two self-conjugative epidemic plasmids, contributing to the widespread MCR-1 and NDM-1 in China. The results of this work improve our understanding of the genetic background of colistin- and carbapenem-resistant K. pneumoniae isolate from bacteremia and the resistance mechanisms. Our findings highlight the urgent need for infection control of such strain to prevent it from becoming an extensive-drug resistant clone.Keywords: Klebsiella pneumoniae, NDM-1, MCR-1, OXA-10, rmpA, bacteremia