(1) Background: Resistance plasmids are under selective conditions beneficial for the bacterial host, but in the absence of selective pressure, this carriage may cause fitness costs. Compensation of this fitness burden is important to obtain competitive ability under antibiotic-free conditions. In this study, we investigated fitness effects after a conjugative transfer of plasmids containing various beta-lactamase genes transferred into Escherichia coli. (2) Methods: Fourteen beta-lactamase-encoding plasmids were transferred from clinical donor strains to E. coli J53. Growth rates were compared for all transconjugants and the recipient. Selected transconjugants were challenged in long-term growth experiments. Growth rates were assessed at different time points during growth for 500 generations. Whole-genome sequencing (WGS) of initial and evolved transconjugants was determined. Results: Most plasmid acquisitions resulted in growth differences, ranging from −4.5% to 7.2%. Transfer of a single bla_CMY-16-carrying plasmid resulted in a growth burden and a growth benefit in independent mating. Long-term growth led to a compensation of fitness burdens and benefits. Analyzing WGS revealed genomic changes caused by Single Nucleotide Polymorphisms (SNPs) and insertion sequences over time. Conclusions: Fitness effects associated with plasmid acquisitions were variable. Potential compensatory mutations identified in transconjugants’ genomes after 500 generations give interesting insights into aspects of plasmid–host adaptations.

中文翻译：

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基于基因组的健身效应和补偿变化与大肠杆菌中blaCMY-，blaCTX-M-和blaOXA-48 / VIM-1质粒的获取相关的分析

（1）背景：抗性质粒处于对细菌宿主有益的选择性条件下，但是在没有选择性压力的情况下，这种转运可能会导致适应性成本。这种健身负担的补偿对于在无抗生素条件下获得竞争能力很重要。在这项研究中，我们调查了含有各种β-内酰胺酶基因的质粒的共轭转移后转移到大肠杆菌中的适应性影响。（2）方法：将十四种β-内酰胺酶编码质粒从临床供体菌株转移到大肠杆菌中。J53。比较所有转导结合体和受体的生长率。在长期生长实验中挑战了选定的转导结合剂。在生长500代的不同时间点评估生长速率。确定了初始和进化的转接合子的全基因组测序（WGS）。结果：大多数质粒采集导致生长差异，范围从-4.5％到7.2％。转让单个bla _CMY-16携带质粒导致独立交配的生长负担和生长益处。长期增长导致对健身负担和福利的补偿。分析WGS揭示了由单核苷酸多态性（SNP）和插入序列引起的基因组变化。结论：与质粒采集相关的适应性效应是可变的。经过500代后在转导结合体基因组中鉴定出的潜在补偿性突变为质粒-宿主适应性方面提供了有趣的见识。