Phenotypic and genotypic characterisation of linezolid-resistant coagulase-negative staphylococci possessing cfr-carrying plasmid
Phenotypic and genotypic characterisation of linezolid-resistant coagulase-negative staphylococci possessing cfr-carrying plasmid
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DOI：
10.1016/j.jgar.2022.01.008
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发表时间：
2022-02-24
影响因子：
4.6
通讯作者：
Li，Rongpeng
中科院分区：
文献类型：
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作者：
Jiang，Fei;Kong，Ziyan;Li，Rongpeng
目的利奈唑胺依赖性生长导致表皮葡萄球菌在医院广泛传播。本研究旨在研究耐利奈唑胺凝固酶阴性葡萄球菌（con）在中国的特点以及利奈唑胺依赖的可能性。方法采用药敏试验和PCR方法对13株con菌株进行表型和基因型耐药分析。采用脉冲场凝胶电泳（PFGE）测定分离菌株的相似性。通过ys1核酸酶PFGE、Southern blotting和全基因组测序（WGS）对携带cfr的质粒进行了表征。构建了最大似然系统发生树进行系统发生分析。用利奈唑胺和不使用利奈唑胺进行生长曲线分析，以确定利奈唑胺依赖对利奈唑胺耐药con传播的可能贡献。结果13株con菌株的耐药浓度为8 ~ 256 mg/L，呈3个PFGE谱。Southern blotting和WGS结果表明，该基因位于一个39.5 kb的质粒上，与含有cfr的质粒pSR01、pLRSA417和pH29-46的同源性为99%。该基因两侧有两个is256样元件isenfa4家族转座酶拷贝，表明该基因具有利奈唑胺耐药的可转移性。对比系统发育分析显示，首都葡萄球菌xz03与耐利奈唑胺药具有高度的相似性。上海华山医院。13株con菌株在8 ~ 32 mg/L的浓度下不表现出利奈唑胺依赖性。结论我院地方性携带该基因的con克隆对利奈唑胺呈高水平耐药性，威胁利奈唑胺的使用。在利奈唑胺选择压力下，没有观察到利奈唑胺依赖性生长，表明它可能还不是一种常见的表型inStaphylococcusspp。
ObjectivesLinezolid-dependent growth has contributed to wide dissemination ofStaphylococcus epidermidisin hospitals. This study aimed to characterise linezolid-resistant coagulase-negative staphylococci (CoNS) isolates and the possibility of linezolid dependence in China.MethodsPhenotypic and genotypic resistance of 13 CoNS isolates were investigated by antimicrobial susceptibility testing and PCR. Similarity of isolates was determined by pulsed-field gel electrophoresis (PFGE). Characterisation of thecfr-carrying plasmid was performed byS1nuclease PFGE, Southern blotting and whole-genome sequencing (WGS). A maximum likelihood phylogenetic tree was constructed for phylogenetic analysis. Growth curve analysis was performed with and without linezolid to determinate the possible contribution of linezolid dependence to linezolid-resistant CoNS dissemination.ResultsThirteen CoNS isolates showed linezolid MICs of 8 mg/L to >256 mg/L, typed into three PFGE profiles. Southern blotting and WGS indicated that thecfrgene was located on a 39.5-kb plasmid with 99% identity tocfr-harbouring plasmids pSR01, pLRSA417 and pH29-46. Thecfrgene was flanked by two copies of an IS256-like element ISEnfa4family transposase, indicating the transferability of linezolid resistance conferred by thecfrgene. Comparative phylogenetic analysis revealed thatStaphylococcus capitisXZ03 shared high similarity with linezolid-resistantS. capitisisolates in Huashan Hospital, Shanghai. Thirteen CoNS isolates did not exhibit linezolid dependence on exposure from 8–32 mg/L.ConclusionThe endemic CoNS clone carrying thecfrgene in our hospital showed high-level linezolid resistance, threatening linezolid use. Linezolid-dependent growth under linezolid selective pressure was not observed, indicating that it may not yet be a common phenotype inStaphylococcusspp.