The evolution of infectious transmission promotes the persistence of mcr-1 plasmids

作者：Jun Yang, Renjie Wu, Qiang Xia, Jingjing Yu, Lingxian Yi, Ying Huang, Meixin Deng, Wan-Yun He, Yuman Bai, Luchao Lv, Vincent Burrus, Cheng-Zhen Wang, Jian–Hua Liu · 发表于：mBio · 年份：2023 · DOI：10.1128/mbio.00442-23 · 被引用次数：18 · 研究领域：Antibiotic Resistance in Bacteria、Bacterial Identification and Susceptibility Testing、Vibrio bacteria research studies

ABSTRACT Conjugative plasmids play a vital role in bacterial evolution and promote the spread of antibiotic resistance. They usually cause fitness costs that diminish the growth rates of the host bacteria. Compensatory mutations are known as an effective evolutionary solution to reduce the fitness cost and improve plasmid persistence. However, whether the plasmid transmission by conjugation is sufficient to improve plasmid persistence is debated since it is an inherently costly process. Here, we experimentally evolved an unstable and costly mcr-1 plasmid pHNSHP24 under laboratory conditions and assessed the effects of plasmid cost and transmission on the plasmid maintenance by the plasmid population dynamics model and a plasmid invasion experiment designed to measure the plasmid’s ability to invade a plasmid-free bacterial population. The persistence of pHNSHP24 improved after 36 days evolution due to the plasmid-borne mutation A51G in the 5′UTR of gene traJ . This mutation largely increased the infectious transmission of the evolved plasmid, presumably by impairing the inhibitory effect of FinP on the expression of traJ . We showed that increased conjugation rate of the evolved plasmid could compensate for the plasmid loss. Furthermore, we determined that the evolved high transmissibility had little effect on the mcr-1 -deficient ancestral plasmid, implying that high conjugation transfer is vital for maintaining the mcr-1 -bearing plasmid. Altogether, our findings emphasized...