质粒介导的利奈唑胺耐药基因optrA在粪肠球菌的水平转移机制  

Mechanism of horizontal transfer of linezolid resistance gene optr A mediated by plasmids in Enterococcus faecalis

作　　者：杨佩霓 陈莉[1] 何薇[1] 翟秀伟[1] 吕梅 王清[1] 杨旭[1] YANG Peini;CHEN Li;HE Wei;ZHAI Xiuwei;LYU Mei;WANG Qing;YANG Xu(Department of Laboratory Medicine,The Second Affiliated Hospital of Kunming Medical University,Kunming 650032,China)

机构地区：[1]昆明医科大学第二附属医院检验科,云南昆明650032

出　　处：《中国感染控制杂志》2025年第1期67-76,共10页Chinese Journal of Infection Control

基　　金：云南省教育厅科学研究基金项目(2023Y0641);昆明医科大学第二附属医院院内科技计划资助项目(2021yk002、2022ky07)。

摘　　要：目的研究临床上耐利奈唑胺粪肠球菌(LREf)携带的optrA基因通过质粒介导在粪肠球菌间的水平转移机制。方法收集昆明市某三级甲等医院2022年8月—2023年8月留取的非重复LREf,使用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)仪进行鉴定,VITEK 2 Compact、纸片扩散法、微量肉汤稀释法进行药敏试验,聚合酶链式反应(PCR)检测optrA基因,全基因组测序(WGS)分析LREf的分子生物学特征,以LREf为供体菌、临床来源粪肠球菌为受体菌进行接合实验。结果共收集17株LREf,12株LREf的质粒检测出optrA基因,检测出多种耐药基因及毒力基因。12株LREf菌株以ST16(50.0%)为主要分型。接合试验的24株接合子中有8株接合成功,接合率为33.3%,进一步分析发现,菌株接合前后位于质粒上的optrA基因上下游均存在IS1216E插入序列,且形成IS1216E-fexA-optrA-erm(A)-IS1216E样的转座单元。结论optrA基因可通过同时携带erm(A)、fexA基因的质粒介导在临床粪肠球菌间进行水平转移,而插入序列IS1216E在其水平转移过程中发挥着重要作用。Objective To study the horizontal transfer mechanism of optr A gene-carrying linezolid-resistant Enterococcus faecalis(LREf)among clinical Enterococcus faecalis mediated by plasmids.Methods Non-repeated LREf from a tertiary first-class hospital in Kunming City from August 2022 to August 2023 were collected and identified by matrix-assisted laser desorption/ionisation-time of flight mass spectrometry(MALDI-TOF MS).Antimicrobial susceptibility testing was performed by VITEK 2 Compact,disc diffusion method and microbroth dilution method,optr A gene was detected by polymerase chain reaction(PCR),molecular biology characteristics of LREf was analyzed by whole-genome sequencing(WGS),LREf as the donor strain and clinically isolated Enterococcus faecalis as the recipient strain for conjugation test.Results A total of 17 LREf strains were collected,optr A gene was detected from plasmids of 12 LREf strains.Multiple resistance genes and virulence genes were detected.12 LREf strains were mainly ST16 type(50.0%).Among the 24 transconjugates in the conjugation test,8 were successfully conjugated,with a conjugation rate of 33.3%.Further analysis revealed that IS1216E insertion sequences presented at upstream and downstream of the optr A gene on the plasmid before and after conjugation of strains,and formed IS1216E-fex A-optr A-erm(A)-IS1216E-like transposon units.Conclusion The optr A gene can be horizontally transferred among clinical Enterococcus faecalis by mediating of plasmid of genes carrying both erm(A)and fex A,and the insertion sequence IS1216E plays an important role in its horizontal transfer process.

关 键 词：粪肠球菌 利奈唑胺 质粒 optrA 全基因组测序 水平转移 

分 类 号：R181.32[医药卫生—流行病学] R378[医药卫生—公共卫生与预防医学]