Central European Institute of Technology, University of Veterinary Sciences Brno, Brno, Czech Republic.
Department of Biology and Wildlife Diseases, University of Veterinary Sciences Brno, Brno, Czech Republic.
J Antimicrob Chemother. 2022 Oct 28;77(11):2960-2963. doi: 10.1093/jac/dkac250.
To investigate the fitness effects of large blaCTX-M-15-harbouring F2:A1:B- plasmids on their native Escherichia coli ST131 H30Rx hosts.
We selected five E. coli ST131 H30Rx isolates of diverse origin, each carrying an F2:A1:B- plasmid with the blaCTX-M-15 gene. The plasmid was eliminated from each isolate by displacement using an incompatible curing plasmid, pMDP5_cureEC958. WGS was performed to obtain complete chromosome and plasmid sequences of original isolates and to detect chromosomal mutations in 'cured' clones. High-throughput competition assays were conducted to determine the relative fitness of cured clones compared with the corresponding original isolates.
We were able to successfully eliminate the F2:A1:B- plasmids from all five original isolates using pMDP5_cureEC958. The F2:A1:B- plasmids produced non-significant fitness effects in three isolates and moderate reductions in relative fitness (3%-4%) in the two remaining isolates.
We conclude that F2:A1:B- plasmids pose low fitness costs in their E. coli ST131 H30Rx hosts. This plasmid-host fitness compatibility is likely to promote the maintenance of antibiotic resistance in this clinically important E. coli lineage.
研究携带大型 blaCTX-M-15 基因的 F2:A1:B- 质粒对其天然大肠杆菌 ST131 H30Rx 宿主的适应度效应。
我们选择了五个来源不同的大肠杆菌 ST131 H30Rx 分离株，每个分离株都携带带有 blaCTX-M-15 基因的 F2:A1:B- 质粒。通过使用不兼容的消除质粒 pMDP5_cureEC958 从每个分离株中消除质粒。进行 WGS 以获得原始分离株的完整染色体和质粒序列，并检测“消除”克隆中的染色体突变。进行高通量竞争测定以确定与相应原始分离株相比，“消除”克隆的相对适应度。
我们能够成功地使用 pMDP5_cureEC958 从所有五个原始分离株中消除 F2:A1:B- 质粒。在三个分离株中，F2:A1:B- 质粒产生的适应度影响不显著，而在另外两个分离株中相对适应度（3%-4%）适度降低。
我们得出结论，F2:A1:B- 质粒在其大肠杆菌 ST131 H30Rx 宿主中产生的适应性代价较低。这种质粒-宿主适应度相容性可能促进了这种在临床上重要的大肠杆菌谱系中抗生素耐药性的维持。
