Pietsch Michael, Pfeifer Yvonne, Fuchs Stephan, Werner Guido
Robert Koch Institute, Department Infectious Diseases, Division Nosocomial Pathogens and Antimicrobial Resistances, Wernigerode Branch, 38855 Wernigerode, Germany.
Robert Koch Institute, Department Methodology and Research Infrastructure, Division Bioinformatics, 13353 Berlin, Germany.
Antibiotics (Basel). 2021 Jan 19;10(1):90. doi: 10.3390/antibiotics10010090.
(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 . (2) Methods: Fourteen beta-lactamase-encoding plasmids were transferred from clinical donor strains to 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 -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.
(1) 背景：耐药质粒在有利于细菌宿主的选择条件下存在，但在没有选择压力时，这种携带可能会导致适应性代价。在无抗生素条件下获得竞争能力，补偿这种适应性负担很重要。在本研究中，我们调查了含有各种β-内酰胺酶基因的质粒接合转移到……后对适应性的影响。(2) 方法：将14种编码β-内酰胺酶的质粒从临床供体菌株转移到J53。比较了所有转接合子和受体的生长速率。在长期生长实验中对选定的转接合子进行挑战。在500代生长过程中的不同时间点评估生长速率。对初始和进化后的转接合子进行全基因组测序（WGS）。结果：大多数质粒获得导致生长差异，范围从-4.5%到7.2%。单个携带……的质粒转移在独立交配中导致生长负担和生长益处。长期生长导致适应性负担和益处得到补偿。分析WGS揭示了随着时间推移由单核苷酸多态性（SNP）和插入序列引起的基因组变化。结论：与质粒获得相关的适应性影响是可变的。在500代后在转接合子基因组中鉴定出的潜在补偿性突变，为质粒-宿主适应性的各个方面提供了有趣的见解。
