Department of Clinical Laboratory, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.
Department of Clinical Laboratory, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.
Ann Clin Microbiol Antimicrob. 2024 Mar 29;23(1):27. doi: 10.1186/s12941-024-00686-3.
Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) co-producing bla and bla poses a serious threat to public health. This study aimed to investigate the mechanisms underlying the resistance and virulence of CR-hvKP isolates collected from a Chinese hospital, with a focus on bla and bla dual-positive hvKP strains.
Five CR-hvKP strains were isolated from a teaching hospital in China. Antimicrobial susceptibility and plasmid stability testing, plasmid conjugation, pulsed-field gel electrophoresis, and whole-genome sequencing (WGS) were performed to examine the mechanisms of resistance and virulence. The virulence of CR-hvKP was evaluated through serum-killing assay and Galleria mellonella lethality experiments. Phylogenetic analysis based on 16 highly homologous carbapenem-resistant K. pneumoniae (CRKP) producing KPC-2 isolates from the same hospital was conducted to elucidate the potential evolutionary pathway of CRKP co-producing NDM and KPC.
WGS revealed that five isolates individually carried three unique plasmids: an IncFIB/IncHI1B-type virulence plasmid, IncFII/IncR-type plasmid harboring KPC-2 and IncC-type plasmid harboring NDM-1. The conjugation test results indicated that the transference of KPC-2 harboring IncFII/IncR-type plasmid was unsuccessful on their own, but could be transferred by forming a hybrid plasmid with the IncC plasmid harboring NDM. Further genetic analysis confirmed that the pJNKPN26-KPC plasmid was entirely integrated into the IncC-type plasmid via the copy-in route, which was mediated by TnAs1 and IS26.
KPC-NDM-CR-hvKP likely evolved from a KPC-2-CRKP ancestor and later acquired a highly transferable bla plasmid. ST11-KL64 CRKP exhibited enhanced plasticity. The identification of KPC-2-NDM-1-CR-hvKP highlights the urgent need for effective preventive strategies against aggravated accumulation of resistance genes.
产碳青霉烯酶且高毒力肺炎克雷伯菌（CR-hvKP）同时携带 bla 和 bla 基因，对公共健康构成严重威胁。本研究旨在探讨中国某医院分离的 CR-hvKP 菌株的耐药和毒力机制，重点关注 bla 和 bla 双阳性 hvKP 菌株。
从中国一家教学医院分离出 5 株 CR-hvKP 菌株。通过药敏试验和质粒稳定性试验、质粒接合试验、脉冲场凝胶电泳和全基因组测序（WGS）来研究耐药和毒力机制。通过血清杀伤试验和家蚕致死实验评估 CR-hvKP 的毒力。对来自同一医院的 16 株高同源产碳青霉烯酶肺炎克雷伯菌（CRKP）中携带 KPC-2 的菌株进行基于 16S rRNA 的系统进化分析，以阐明 CRKP 同时携带 NDM 和 KPC 的潜在进化途径。
WGS 显示，5 个分离株分别携带 3 种独特的质粒：一种 IncFIB/IncHI1B 型毒力质粒、一种携带 KPC-2 的 IncFII/IncR 型质粒和一种携带 NDM-1 的 IncC 型质粒。接合试验结果表明，携带 KPC-2 的 IncFII/IncR 型质粒不能单独转移，但可以与携带 NDM 的 IncC 型质粒形成杂交质粒进行转移。进一步的遗传分析证实，pJNKPN26-KPC 质粒完全通过复制途径整合到 IncC 型质粒中，这一过程由 TnAs1 和 IS26 介导。
KPC-NDM-CR-hvKP 可能是由 KPC-2-CRKP 祖先进化而来，后来获得了一个可高度转移的 bla 质粒。ST11-KL64 CRKP 表现出更高的可塑性。KPC-2-NDM-1-CR-hvKP 的鉴定凸显了对加剧耐药基因积累的有效预防策略的迫切需求。
