比较基因组分析 pTEM-2262，一种源自弗氏柠檬酸杆菌的 MDR 质粒，携带有两个未分类的复制子。
Comparative genomics analysis of pTEM-2262, an MDR plasmid from Citrobacter freundii, harboring two unclassified replicons.
机构信息
College of Life Science, Hebei Normal University, Shijiazhuang, Hebei 050024, PR China.
State Key Laboratory of Pathogen & Biosecurity, Beijing Institute of Microbiology & Epidemiology, Beijing 100071, PR China.
出版信息
Future Microbiol. 2018 Nov;13:1657-1668. doi: 10.2217/fmb-2018-0243. Epub 2018 Nov 30.
AIM
To genetically characterize the multidrug-resistance (MDR) plasmid pTEM-2262 that could not be classified into any known incompatibility group from the clinical Citrobacter freundii isolate 2262.
MATERIALS & METHODS: The repA or repB deletion mutants of pTEM-2262 were constructed using the scarless Cas9-assisted recombineering system. Comparative genomic analysis of pTEM-2262 and the other four previously sequenced plasmids belonging to the same incompatibility group were performed.
RESULTS
pTEM-2262, a conjugative plasmid, harbored two unclassified replicons, repA and repB, while repB was not essential for pTEM-2262 replication. In five analyzed plasmids, their conserved backbones primarily integrated massive accessory modules at two 'hotspots' that were located between orf597 and orf504, and between orf393 and orf405. All the antibiotic resistance genes of pTEM-2262 were clustered in the MDR region with a complex mosaic structure.
CONCLUSION
This study thoroughly investigates the detailed structure and genomic comparison of this unknown incompatibility group for the first time.
目的
对临床弗氏柠檬酸杆菌分离株 2262 中无法归入任何已知不相容群的多药耐药（MDR）质粒 pTEM-2262 进行基因特征分析。
材料与方法
利用无痕 Cas9 辅助重组系统构建了 pTEM-2262 的 repA 或 repB 缺失突变体。对 pTEM-2262 和其他四个属于同一不相容群的已测序质粒进行了比较基因组分析。
结果
pTEM-2262 是一个可接合的质粒，携带两个未分类的复制子 repA 和 repB，而 repB 对 pTEM-2262 的复制不是必需的。在分析的五个质粒中，它们的保守骨架主要在位于 orf597 和 orf504 之间以及 orf393 和 orf405 之间的两个“热点”处整合了大量辅助模块。pTEM-2262 的所有抗生素耐药基因都聚集在 MDR 区域，具有复杂的镶嵌结构。
结论
本研究首次对这个未知不相容群进行了详细结构和基因组比较的全面调查。
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