Zhang Fushan, Li Leyuan, Zhao Yuxin, Dong Huiyue, Zhao Buhui, Zhao Xiaoyu, Xia Ziwei, Chi Leizi, Wang Yan, Li Ruichao, Qin Shangshang, Fu Xiangjing
Department of Clinical Laboratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan, China.
Front Microbiol. 2024 Mar 14;15:1353849. doi: 10.3389/fmicb.2024.1353849. eCollection 2024.
Carbapenem-resistant hypervirulent (CR-HvKP) strains combining virulence and multidrug resistance (MDR) features pose a great public health concern. The aim of this study is to explore the evolutionary characteristics of virulence in CR-HvKP by investigating the genetic features of resistance and virulence hybrid plasmids.
The resistance and virulence phenotypes were determined by using antimicrobial susceptibility testing and the mouse bacteremia infection model, respectively. Plasmid profiles were investigated by S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) and Southern blotting, conjugation assay, and whole genome sequencing (WGS). Bioinformatics tools were used to uncover the genetic features of the resistance and virulence hybrid plasmids.
Two ST11-KL64 CRKP clinical isolates (KP18-3-8 and KP18-2079), which exhibited enhanced virulence compared with the classic CRKP, were detected positive for and . The virulence level of the hypermucoviscous strain KP18-3-8 was higher than that of KP18-2079. S1-PFGE, Southern hybridization and WGS analysis identified two novel hybrid virulence plasmids in KP18-3-8 (pKP1838-KPC-vir, 228,158 bp) and KP18-2079 (pKP1838-KPC-vir, 182,326 bp), respectively. The IncHI1B/repB-type plasmid pKP1838-KPC-vir co-harboring and virulence genes ( and A) but lacking type IV secretion system could transfer into non-hypervirulent ST11 with the assistance of a helper plasmid in conjugation. The IncFII/IncR-type virulence plasmid pKP18-2079-vir may have been generated as a result of recombination between a typical pLVPK-like virulence plasmid and an MDR plasmid.
Our studies further highlight co-evolution of the virulence and resistance plasmids in ST11-CRKP isolates. Close surveillance of such hybrid virulence plasmids in clinical should be performed.
具有毒力和多重耐药（MDR）特性的耐碳青霉烯类高毒力肺炎克雷伯菌（CR-HvKP）菌株引起了极大的公共卫生关注。本研究的目的是通过研究耐药性和毒力杂交质粒的遗传特征，探索CR-HvKP中毒力的进化特征。
分别采用抗菌药物敏感性试验和小鼠菌血症感染模型确定耐药性和毒力表型。通过S1核酸酶脉冲场凝胶电泳（S1-PFGE）、Southern印迹、接合试验和全基因组测序（WGS）研究质粒图谱。使用生物信息学工具揭示耐药性和毒力杂交质粒的遗传特征。
检测到两株ST11-KL64 CRKP临床分离株（KP18-3-8和KP18-2079），与经典CRKP相比，它们表现出增强的毒力， 和 检测呈阳性。高黏液性菌株KP18-3-8的毒力水平高于KP18-2079。S1-PFGE、Southern杂交和WGS分析分别在KP18-3-8（pKP1838-KPC-vir，228,158 bp）和KP18-2079（pKP1838-KPC-vir，182,326 bp）中鉴定出两种新型杂交毒力质粒。携带 和毒力基因（ 和A）但缺乏IV型分泌系统的IncHI1B/repB型质粒pKP1838-KPC-vir可在接合过程中在辅助质粒的帮助下转移到非高毒力ST11中。IncFII/IncR型毒力质粒pKP18-2079-vir可能是典型的pLVPK样毒力质粒与MDR质粒之间重组的结果。
我们的研究进一步强调了ST11-CRKP分离株中毒力和耐药性质粒的共同进化。应对临床中此类杂交毒力质粒进行密切监测。
