从地表水分离到一株携带 optrA 的 Tn6674 样元件的耐林可酰胺类肠球菌 16 型。

Linezolid-resistant Enterococcus faecalis ST16 harbouring optrA on a Tn6674-like element isolated from surface water.

机构信息

Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Winterthurerstrasse 272, CH-8057 Zürich, Switzerland.

出版信息

J Glob Antimicrob Resist. 2021 Jun;25:89-92. doi: 10.1016/j.jgar.2021.02.029. Epub 2021 Mar 8.

DOI:10.1016/j.jgar.2021.02.029

PMID:33705941

Abstract

OBJECTIVES

The objective of this work was to characterise an optrA-carrying Enterococcus faecalis ST16 isolate recovered from a river water sample in Switzerland.

METHODS

Linezolid-resistant E. faecalis F102 was recovered from surface water in Switzerland and was subjected to comprehensive genotypic characterisation and analysis of the genetic environment of the oxazolidinone/phenicol resistance gene optrA. Whole-genome sequencing (WGS) was performed to detect linezolid resistance mechanisms, including mutations in 23S rRNA and ribosomal protein genes as well as acquired resistance genes. The isolate was further characterised by multilocus sequence typing (MLST) and identification of virulence genes.

RESULTS

WGS detected the presence of optrA identical to the original optrA gene from E. faecalis E349. Analysis of the genetic environment revealed the association of optrA with fexA and a Tn6674-like transposon in co-existence with spc and erm(A) resistance genes. Sequence alignment indicated that the genetic environment of optrA was identical to a Tn6674-like variant from E. faecalis previously isolated from diseased and healthy humans and food-producing animals in the Asia-Pacific region. Enterococcus faecalis F102 did not contain any mutations in 23S rRNA or in genes encoding ribosomal proteins L3, L4 and L22. A total of 14 other resistance genes and 16 virulence genes were detected. Enterococcus faecalis F102 was assigned in silico to ST16.

CONCLUSION

The spread of optrA-carrying E. faecalis ST16 with a high pathogenic potential in surface water is a worrisome aspect from a public-health perspective.

摘要

目的

本研究旨在对从瑞士河水中分离出的一株携带 optrA 的屎肠球菌 ST16 进行特征分析。

方法

从瑞士地表水分离出耐(linezolid)-屎肠球菌 F102，对其进行综合基因特征分析和 oxazolidinone/氯霉素耐药基因 optrA 的遗传环境分析。采用全基因组测序（WGS）检测耐(linezolid)机制，包括 23S rRNA 和核糖体蛋白基因的突变以及获得性耐药基因。通过多位点序列分型（MLST）和毒力基因鉴定进一步对该分离株进行了特征分析。

结果

WGS 检测到存在与屎肠球菌 E349 原始 optrA 基因相同的 optrA。遗传环境分析表明，optrA 与 fexA 和 Tn6674 样转座子共存，同时存在 spc 和 erm(A)耐药基因。序列比对表明，optrA 的遗传环境与之前从亚太地区患病和健康人群以及食品生产动物中分离出的屎肠球菌 Tn6674 样变体相同。屎肠球菌 F102 23S rRNA 或编码核糖体蛋白 L3、L4 和 L22 的基因中均未发现突变。共检测到 14 个其他耐药基因和 16 个毒力基因。屎肠球菌 F102 经计算机预测属于 ST16。