两种不同的缀合质粒可以在细菌细胞内相互作用。然而,据我们所知,携带blaCTX-M的IncFII质粒与位于同一细菌宿主上的携带mcr-1的IncI2质粒之间的相互作用尚未报道。本研究旨在探索这两种质粒在多重耐药大肠杆菌中的相互作用并分析其共同存在的原因。为了评估质粒稳定性的相互作用,健身费用,和传输速率,我们构建了两组同基因衍生物,C600FII,大肠杆菌C600和J53FII的C600I2和C600FII+I2,大肠杆菌J53的J53I2和J53FII+I2。我们发现FII和I2质粒的运输,独立和一起,没有损害细菌宿主的生长。大肠杆菌C600中的单质粒FII或I2很难在无抗生素环境中长时间达到稳定的持久性,而当它们联居时,稳定性会显著提高。同时,质粒FII和I2,无论是一起还是分开,可以显着增强主持人的健身优势;此外,携带质粒FII和I2的大肠杆菌比携带单质粒FII的大肠杆菌具有更明显的适应性优势。共存质粒FII和I2可以通过缀合加速水平共转。携带共同FII和I2质粒的菌株与携带其中之一的受体细胞交配时,其转移率显着增加。我们的发现强调了大肠杆菌中共同存活的FII和I2质粒的优势,以驱动携带质粒的blaCTX-M和mcr-1基因的持久性和传播。尽管它们共同居住的分子机制需要进一步研究。重要性越来越多的肠杆菌同时携带blaCTX-M和mcr-1,它们通常位于同一细菌宿主的IncFII型和IncI2型质粒上,分别。然而,关于共存质粒在细菌宿主中的优势的研究仍然很少。这里,我们研究了稳定性,健身费用,以及与大肠杆菌中共存的IncFII型和IncI2型质粒相关的共转移性状。我们的研究结果表明,大肠杆菌中的共生质粒更稳定,赋予更多健身优势,并且比单个质粒IncFII或IncI2更容易转移和共转。我们的发现证实了携带blaCTX-M的IncFII和携带mcr-1的IncI2的共存质粒在临床大肠杆菌中的优势,这将对临床治疗和公众健康构成严重威胁。
Two diverse conjugative plasmids can interact within bacterial cells. However, to the best of our knowledge, the interaction between blaCTX-M-bearing
IncFII plasmid and mcr-1-carrying IncI2 plasmid colocated on the same bacterial host has not been reported. This study was initiated to explore the interaction and to analyze the reasons that these two plasmids are often coresident in multidrug-resistant Escherichia coli. To assess the interactions on plasmid stabilities, fitness costs, and transfer rates, we constructed two groups of isogenic derivatives, C600FII, C600I2, and C600FII+I2 of E. coli C600 and J53FII, J53I2, and J53FII+I2 of E. coli J53, respectively. We found that carriage of FII and I2 plasmids, independently and together, had not impaired the growth of the bacterial host. It was difficult for the single plasmid FII or I2 in E. coli C600 to reach stable persistence for a long time in an antibiotic-free environment, while the stability would be striking improved when they coresided. Meanwhile, plasmids FII and I2, whether together or apart, could notably enhance the fitness advantage of the host; moreover, E. coli coharboring plasmids FII and I2 presented more obvious fitness advantage than that carrying single plasmid FII. Coresident plasmids FII and I2 could accelerate horizontal cotransfer by conjugation. The transfer rates from a strain carrying coresident FII and I2 plasmids increased significantly when it mated with a recipient cell carrying one of them. Our findings highlight the advantages of coinhabitant FII and I2 plasmids in E. coli to drive the persistence and spread of plasmid-carried blaCTX-M and mcr-1 genes, although the molecular mechanisms of their coresidence warrant further study. IMPORTANCE More and more Enterobacteriaceae carry both blaCTX-M and mcr-1, which are usually located on
IncFII-type and IncI2-type plasmids in the same bacterial host, respectively. However, the study on advantages of coresident plasmids in bacterial host is still sparse. Here, we investigated the stability, fitness cost, and cotransfer traits associated with coresident
IncFII-type and IncI2-type plasmids in E. coli. Our results show that coinhabitant plasmids in E. coli are more stable, confer more fitness advantages, and are easier to transfer and cotransfer than a single plasmid
IncFII or IncI2. Our findings confirm the advantages of coresident plasmids of blaCTX-M-bearing
IncFII and mcr-1-bearing IncI2 in clinical E. coli, which will pose a serious threat to clinical therapy and public health.