Abstract：
Linezolid-dependent growth has contributed to wide dissemination of Staphylococcus epidermidis in hospitals. This study aimed to characterise linezolid-resistant coagulase-negative staphylococci (CoNS) isolates and the possibility of linezolid dependence in China.
Phenotypic 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 the cfr-carrying plasmid was performed by S1 nuclease 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.
Thirteen CoNS isolates showed linezolid MICs of 8 mg/L to >256 mg/L, typed into three PFGE profiles. Southern blotting and WGS indicated that the cfr gene was located on a 39.5-kb plasmid with 99% identity to cfr-harbouring plasmids pSR01, pLRSA417 and pH29-46. The cfr gene was flanked by two copies of an IS256-like element ISEnfa4 family transposase, indicating the transferability of linezolid resistance conferred by the cfr gene. Comparative phylogenetic analysis revealed that Staphylococcus capitis XZ03 shared high similarity with linezolid-resistant S. capitis isolates in Huashan Hospital, Shanghai. Thirteen CoNS isolates did not exhibit linezolid dependence on exposure from 8-32 mg/L.
The endemic CoNS clone carrying the cfr gene 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 in Staphylococcus spp.
Phenotypic 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 the cfr-carrying plasmid was performed by S1 nuclease 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.
Thirteen CoNS isolates showed linezolid MICs of 8 mg/L to >256 mg/L, typed into three PFGE profiles. Southern blotting and WGS indicated that the cfr gene was located on a 39.5-kb plasmid with 99% identity to cfr-harbouring plasmids pSR01, pLRSA417 and pH29-46. The cfr gene was flanked by two copies of an IS256-like element ISEnfa4 family transposase, indicating the transferability of linezolid resistance conferred by the cfr gene. Comparative phylogenetic analysis revealed that Staphylococcus capitis XZ03 shared high similarity with linezolid-resistant S. capitis isolates in Huashan Hospital, Shanghai. Thirteen CoNS isolates did not exhibit linezolid dependence on exposure from 8-32 mg/L.
The endemic CoNS clone carrying the cfr gene 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 in Staphylococcus spp.
摘要：
依赖利奈唑胺的生长促进了表皮葡萄球菌在医院的广泛传播。本研究旨在描述耐利奈唑胺凝固酶阴性葡萄球菌（CoNS）分离株的特征以及中国对利奈唑胺依赖的可能性。
通过药敏试验和PCR检测13株CoNS的表型和基因型耐药性。通过脉冲场凝胶电泳（PFGE）确定分离株的相似性。携带cfr的质粒的表征通过S1核酸酶PFGE进行，Southern印迹和全基因组测序（WGS）。构建了最大似然系统发育树进行系统发育分析。在有和没有利奈唑胺的情况下进行生长曲线分析，以确定利奈唑胺依赖性对利奈唑胺抗性CoNS传播的可能贡献。
13株CoNS分离株显示利奈唑胺的MIC为8mg/L至>256mg/L，键入三个PFGE配置文件。Southern印迹和WGS表明，cfr基因位于39.5kb的质粒上，与携带cfr的质粒pSR01，pLRSA417和pH29-46具有99％的同一性。cfr基因的侧翼是两个IS256样元件ISEnfa4家族转座酶的拷贝，表明cfr基因赋予的利奈唑胺抗性的可转移性。比较系统发育分析显示，华山医院的头孢葡萄球菌XZ03与耐利奈唑胺的头孢葡萄球菌具有很高的相似性。上海。13种CoNS分离株对8-32mg/L的暴露没有利奈唑胺依赖性。
我院携带cfr基因的地方性CoNS克隆显示出高水平的利奈唑胺耐药性，威胁利奈唑胺的使用。未观察到利奈唑胺选择性压力下依赖利奈唑胺的生长，这表明它可能还不是葡萄球菌属的常见表型。
通过药敏试验和PCR检测13株CoNS的表型和基因型耐药性。通过脉冲场凝胶电泳（PFGE）确定分离株的相似性。携带cfr的质粒的表征通过S1核酸酶PFGE进行，Southern印迹和全基因组测序（WGS）。构建了最大似然系统发育树进行系统发育分析。在有和没有利奈唑胺的情况下进行生长曲线分析，以确定利奈唑胺依赖性对利奈唑胺抗性CoNS传播的可能贡献。
13株CoNS分离株显示利奈唑胺的MIC为8mg/L至>256mg/L，键入三个PFGE配置文件。Southern印迹和WGS表明，cfr基因位于39.5kb的质粒上，与携带cfr的质粒pSR01，pLRSA417和pH29-46具有99％的同一性。cfr基因的侧翼是两个IS256样元件ISEnfa4家族转座酶的拷贝，表明cfr基因赋予的利奈唑胺抗性的可转移性。比较系统发育分析显示，华山医院的头孢葡萄球菌XZ03与耐利奈唑胺的头孢葡萄球菌具有很高的相似性。上海。13种CoNS分离株对8-32mg/L的暴露没有利奈唑胺依赖性。
我院携带cfr基因的地方性CoNS克隆显示出高水平的利奈唑胺耐药性，威胁利奈唑胺的使用。未观察到利奈唑胺选择性压力下依赖利奈唑胺的生长，这表明它可能还不是葡萄球菌属的常见表型。
