ABSTRACT

K1/K2 hvKP strains acquire carbapenem-resistance plasmids, known as CR-hvKp, and carbapenem-resistant Klebsiella pneumoniae (CRKP) strains obtain virulence plasmids, recognized as hv-CRKP. The two different evolution patterns of hypervirulent combined carbapenem-resistant Klebsiella pneumoniae may lead to their different prevalence in hospitals. Our study aimed to investigate the prevalence of hv-CRKP and CR-hvKp strains and to analyze factors influencing their evolution and prevalence. We collected 890 K. pneumoniae genomes from GenBank and 530 clinical K. pneumoniae isolates from nine hospitals. Our study found that hv-CRKP strains were more prevalent than CR-hvKp strains and both were dominated by bla_KPC-2 gene. The bla_KPC-2-carrying plasmids could mobilize non-conjugative virulence plasmids from hvKp strains to CRKP strains. The conserved oriT of virulence plasmids and the widespread of conjugative helper plasmids were potential factors for the mobilization of non-conjugative virulence plasmids. HvKp strains with KPC plasmid could hardly simultaneously exhibit hypervirulence and carbapenem resistance as CRKP strains with virulence plasmid, and we found that rfaH mutation reduced capsular synthesis and increased carbapenem resistance of the CR-hvKp strain. In summary, this study revealed that hv-CRKP strains were more suitable for survival in hospital settings than CR-hvKp strains and the widespread conjugative KPC-producing plasmids contributed to the emergence and prevalence of hv-CRKP strains.

摘要

K1/K2 hvKP 菌株获得耐碳青霉烯类质粒，称为 CR-hvKp，耐碳青霉烯类肺炎克雷伯菌(CRKP) 菌株获得毒力质粒，称为 hv-CRKP。高毒力联合耐碳青霉烯类肺炎克雷伯菌的两种不同进化模式可能导致其在医院的流行程度不同。我们的研究旨在调查 hv-CRKP 和 CR-hvKp 菌株的流行情况，并分析影响其进化和流行的因素。我们从 GenBank 收集了 890个肺炎克雷伯菌基因组和来自九家医院的530 个临床肺炎克雷伯菌分离株。我们的研究发现 hv-CRKP 菌株比 CR-hvKp 菌株更普遍，并且两者都以bla为主_KPC-2基因。携带bla _KPC-2的质粒可以将非结合毒力质粒从hvKp菌株转移到CRKP菌株。毒力质粒的保守oriT和结合辅助质粒的广泛存在是非结合毒力质粒动员的潜在因素。带有 KPC 质粒的 HvKp 菌株几乎不能像带有毒力质粒的 CRKP 菌株一样同时表现出高毒力和碳青霉烯类耐药性，我们发现rfaH突变减少了 CR-hvKp 菌株的荚膜合成并增加了碳青霉烯类药物的抗性。总之，这项研究表明，hv-CRKP 菌株比 CR-hvKp 菌株更适合在医院环境中生存，并且广泛的结合 KPC 生产质粒有助于 hv-CRKP 菌株的出现和流行。