中国一家三甲医院中产 KPC 的 ST15 菌株的爆发：耐药性和毒力分析。

Outbreak of KPC-producing ST15 strains in a Chinese tertiary hospital: resistance and virulence analyses.

机构信息

The Fifth Affiliated Hospital of Wenzhou Medical University, Lishui, Zhejiang, PR China.

Lishui Center for Disease Control and Prevention, Lishui, Zhejiang, 323000, PR China.

出版信息

J Med Microbiol. 2022 Feb;71(2). doi: 10.1099/jmm.0.001494.

DOI:10.1099/jmm.0.001494

PMID:35156610

Abstract

Carbapenem-resistant (CRKP) is a major cause of clinical infection. However, carbapenemase (KPC)-producing ST15 strains are occasionally identified and have seldom been reported to cause hospital outbreaks in PR China. In this study, we describe nosocomial outbreaks caused by KPC-producing ST15 strains in a Chinese tertiary hospital. To characterize the molecular relationship, resistance and virulence factors of the 32 KPC-producing ST15 strains isolated in a Chinese hospital. A total of 102 non-repetitive carbapenem-resistant (CRE) strains were collected from a Chinese tertiary hospital in 2018. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were performed to characterize the clonal relationship of the isolates, and the ST15 strains were selected for further study. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Fifteen carbapenem resistance genes, genetic structures and 12 virulence factors were detected by PCR. Whole-genome sequencing (WGS) was performed using next-generation sequencing combined with single-molecule real-time sequencing. Thirty-two ST15 strains were characterized, and 31 of them presented a PFGE similarity of >92 %, indicating clonal spread. In 81.3 % (26/32) of strains, the imipenem (IPM) and meropenem (MEM) MICs were ≤8 and≤16 µg ml, while only 1 isolate (KP18069) exhibited ≥64 µg ml for both agents. The gene embedded in the Tn-Tn chimaera and synonymous mutations of the gene were detected in all the strains. However, a nonsense mutation at amino acid position 248 (K248X) of OmpK36 was found in the highly carbapenem-resistant strain KP18069. No virulence gene was detected in any of the ST15 strains. WGS analyses further confirmed the genetic characteristics of the KP18069 strain. Nosocomial outbreaks caused by the clonal spread of ST15 strains were characterized in a Chinese tertiary hospital, and strict monitoring of highly resistant CRKP is required.

摘要

耐碳青霉烯肠杆菌科细菌（CRKP）是临床感染的主要原因。然而，产碳青霉烯酶（KPC）的 ST15 菌株偶尔被鉴定出来，并且在中国很少有报道称其导致医院爆发。在本研究中，我们描述了中国一家三级医院由产 KPC 的 ST15 菌株引起的医院感染爆发。为了描述 32 株在中国医院分离的产 KPC 的 ST15 菌株的分子关系、耐药性和毒力因子。2018 年，从中国一家三级医院收集了 102 株非重复耐碳青霉烯类（CRE）菌株。采用多位点序列分型（MLST）和脉冲场凝胶电泳（PFGE）对分离株的克隆关系进行了分析，并选择了 ST15 株进行进一步研究。采用肉汤微量稀释法测定最小抑菌浓度（MIC），并根据临床和实验室标准协会（CLSI）指南进行解释。采用 PCR 检测了 15 种碳青霉烯耐药基因、基因结构和 12 种毒力因子。采用下一代测序结合单分子实时测序进行全基因组测序（WGS）。对 32 株 ST15 菌株进行了特征描述，其中 31 株菌株的 PFGE 相似度>92%，表明存在克隆传播。在 81.3%（26/32）的菌株中，亚胺培南（IPM）和美罗培南（MEM）的 MICs 均≤8 和≤16μg/ml，而只有 1 株（KP18069）对这两种药物的 MICs 均≥64μg/ml。所有菌株均检测到嵌合 Tn-Tn 中的基因和基因的同义突变，但在高度耐碳青霉烯的 KP18069 菌株中发现了 OmpK36 氨基酸位置 248 处的无义突变（K248X）。在任何一株 ST15 菌株中均未检测到毒力基因。WGS 分析进一步证实了 KP18069 菌株的遗传特征。在中国一家三级医院，我们对由 ST15 菌株克隆传播引起的医院感染爆发进行了特征描述，需要对高度耐药的 CRKP 进行严格监测。