Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong Universitygrid.16821.3c School of Medicine, Shanghai, China.
State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong Universitygrid.16821.3c, Shanghai, China.
Microbiol Spectr. 2022 Aug 31;10(4):e0136422. doi: 10.1128/spectrum.01364-22. Epub 2022 Jul 14.
Klebsiella pneumoniae poses a critical challenge to clinical and public health. Along with conjugative plasmids, nonconjugative resistance or virulence plasmids associated with carbapenem-resistant K. pneumoniae (CRKP), hypervirulent K. pneumoniae (hvKP), and even carbapenem-resistant and hypervirulent K. pneumoniae (CR-hvKP) strains have been spreading globally. In this study, a clinical CRKP strain KP2648 was isolated, and the transferability of its plasmids was assessed using conjugation experiments. The transconjugants were characterized by polymerase chain reaction (PCR) detection, I and S1-pulsed-field gel electrophoresis (PFGE), and/or whole-genome sequencing. Genetically modified IncN3 plasmids were employed to elucidate the self-transferability and the mobilization mechanisms. KP2648 has three natural plasmids: a nonconjugative IncFIB/IncHI3B virulence plasmid, a nonconjugative IncFII/IncR carbapenem-resistant plasmid, and a self-transferable IncN3 plasmid with a high conjugation frequency (7.54 ± 1.06) × 10. The IncN3 plasmid could mobilize the coexisting nonconjugative virulence/resistance plasmids either directly or by employing intermediate E. coli with two forms: a hybrid plasmid fused with IncN3 or a cotransfer with the helper plasmid, IncN3. Various mobile genetic elements, including IS, IS, IS, IS, IS, and Tn are involved in the genetic transposition of diverse hybrid plasmids and the cotransfer process during the intra/interspecies transmission. Nowadays, the underlying mobilization mechanism and evolutionary processes of nonconjugative virulence or resistance plasmids in Klebsiella pneumoniae remain poorly understood. Our study revealed the high conjugation ability of IncN3 plasmid isolated from carbapenem-resistant K. pneumoniae and confirmed its capability to mobilize the nonconjugative virulence or resistance plasmids. The self-transferable IncN3 plasmid could facilitate the transmission of pathogenicity and genetic evolution of carbapenem-resistant and hypervirulent K. pneumoniae, including hv-CRKP (virulence plasmid obtained by carbapenem-resistant K. pneumoniae) and CR-hvKP (resistance plasmid obtained by hypervirulent K. pneumoniae), warranting further monitoring.
肺炎克雷伯菌对临床和公共卫生构成重大挑战。除了接合质粒外，与碳青霉烯类耐药肺炎克雷伯菌（CRKP）、高毒力肺炎克雷伯菌（hvKP）甚至碳青霉烯类耐药和高毒力肺炎克雷伯菌（CR-hvKP）菌株相关的非接合性耐药或毒力质粒也在全球范围内传播。在这项研究中，分离出了一株临床 CRKP 菌株 KP2648，并通过接合实验评估了其质粒的可转移性。通过聚合酶链反应（PCR）检测、I 和 S1 脉冲场凝胶电泳（PFGE）和/或全基因组测序对转导体进行了特征分析。采用基因修饰的 IncN3 质粒来阐明其自我转移能力和迁移机制。KP2648 有三个天然质粒：一个非接合性 IncFIB/IncHI3B 毒力质粒、一个非接合性 IncFII/IncR 碳青霉烯类耐药质粒和一个具有高接合频率（7.54±1.06）×10-7 的可自我转移的 IncN3 质粒。IncN3 质粒可以直接或通过利用两种形式的中间大肠杆菌（带有 IncN3 的杂交质粒或与辅助质粒 IncN3 共转移）来动员共存的非接合性毒力/耐药质粒。各种移动遗传元件，包括 IS、IS、IS、IS、IS 和 Tn，参与了不同杂交质粒的基因转位和种内/种间转移过程中的共转移。目前，肺炎克雷伯菌中非接合性毒力或耐药质粒的潜在迁移机制和进化过程仍知之甚少。本研究揭示了从碳青霉烯类耐药肺炎克雷伯菌中分离出的 IncN3 质粒的高接合能力，并证实了其动员非接合性毒力或耐药质粒的能力。可自我转移的 IncN3 质粒可促进包括高毒力碳青霉烯类耐药肺炎克雷伯菌（hv-CRKP，从碳青霉烯类耐药肺炎克雷伯菌获得的毒力质粒）和耐药高毒力肺炎克雷伯菌（CR-hvKP，从高毒力肺炎克雷伯菌获得的耐药质粒）在内的碳青霉烯类耐药和高毒力肺炎克雷伯菌的致病性和遗传进化的传播，值得进一步监测。
