Liao, Liu, Chen, Li, Du, Long, Zhang (2019) Distribution of CRISPR-Cas Systems in Clinical Carbapenem-Resistant Klebsiella pneumoniae Strains in a Chinese Tertiary Hospital and Its Potential Relationship with Virulence Microbial drug resistance (Larchmont, N.Y.) ()

Abstract

Aim: In this study, we aimed to characterize the CRISPR-Cas systems in clinical carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates and to investigate the potential association of CRISPR-Cas systems with bacterial virulence. Methods: A total of 168 CRKP strains were collected from inpatients in a teaching hospital in Jiangxi Province. Five common carbapenemase genes, subtype genes of the CRISPR-Cas system, and 13 virulence genes were amplified by PCR using specific primers. The potential virulence of all the clinical CRKP strains was tested in a Galleria mellonella infection model. Results: PCR analysis of five common carbapenemase genes revealed the frequency of carbapenemase gene KPC-2 was the highest in the CRISPR-negative strains, compared to CRISPR type I-E* strains or CRISPR type I-E strains (p < 0.01). Isolates having the subtype I-E* CRISPR-Cas system tended to have more virulence genes such as magA, kfu, wcaG, and allS, compared to CRISPR-negative isolates and type I-E CRISPR-Cas isolates (p < 0.01). The average survival time of the larvae infected with the isolates having the subtype I-E* CRISPR-Cas system was significantly shorter than the other two group isolates (p < 0.05). Conclusion: The CRKP strains, which had the subtype I-E CRISPR-Cas system or the subtype I-E* CRISPR-Cas system, showed reduced acquisition of carbapenemase genes compared to CRISPR-negative isolates. Importantly, we first found that a small portion of "CR-hvKP" strains were selected from the CRKP clones, which had the type I-E* CRISPR-Cas systems.

目的:在这项研究中,我们旨在表征临床耐碳青霉烯类肺炎克雷伯菌(CRKP)分离物中的CRISPR-Cas系统,并研究CRISPR-Cas系统与细菌毒力的潜在关联。方法:从江西省某教学医院住院患者中共采集168株CRKP菌株。使用特异性引物通过PCR扩增了五个常见的碳青霉烯酶基因,CRISPR-Cas系统的亚型基因和13个毒力基因。所有的临床CRKP菌株的潜在毒力已在马卢埃勒(Galleria mellonella)感染模型中进行了测试。结果:对五个常见碳青霉烯酶基因的PCR分析显示,与CRISPR型IE *菌株或CRISPR型IE菌株相比,在CRISPR阴性菌株中碳青霉烯酶基因KPC-2的频率最高(p <0.01)。与CRISPR阴性分离株和IE CRISPR-Cas型分离株相比,具有IE * CRISPR-Cas系统亚型的菌株倾向于具有更多的毒力基因,例如magA,kfu,wcaG和allS。被具有IE * CRISPR-Cas系统亚型的分离株感染的幼虫的平均存活时间明显短于其他两组分离株(p <0.05)。结论:与CRISPR阴性分离株相比,具有IE CRISPR-Cas亚型或IE * CRISPR-Cas亚型的CRKP菌株显示碳青霉烯酶基因的获得减少。重要的是,我们首先发现一小部分“ CR-hvKP”菌株是从具有IE * CRISPR-Cas系统类型的CRKP克隆中选择的。

Links

http://www.ncbi.nlm.nih.gov/pubmed/31834846
http://dx.doi.org/10.1089/mdr.2019.0276

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