Effects of antibiotic resistance alleles on bacterial evolutionary responses to viral parasites

Antibiotic resistance has wide-ranging effects on bacterial phenotypes and evolution. However, the influence of antibiotic resistance on bacterial responses to parasitic viruses remains unclear, despite the ubiquity of such viruses in nature and current interest in therapeutic applications. We experimentally investigated this by exposing various Escherichia coli genotypes, including eight antibiotic-resistant genotypes and a mutator, to different viruses (lytic bacteriophages). Across 960 populations, we measured changes in population density and sensitivity to viruses, and tested whether variation among bacterial genotypes was explained by their relative growth in the absence of parasites, or mutation rate towards phage resistance measured by fluctuation tests for each phage. We found that antibiotic resistance had relatively weak effects on adaptation to phages, although some antibiotic-resistance alleles impeded the evolution of resistance to phages via growth costs. By contrast, a m...抗生素耐药性（Antibiotic resistance）对细菌表型（bacterial phenotypes）与进化进程具有广泛影响。尽管这类病毒在自然界中广泛存在且在治疗应用领域备受关注，但抗生素耐药性对细菌应对寄生病毒的响应的影响仍不明确。本研究通过将包含8种抗生素耐药性基因型与1株突变株（mutator）在内的多种大肠杆菌（Escherichia coli）基因型暴露于不同病毒（裂解性噬菌体（lytic bacteriophages））中，针对该问题开展了实验研究。在共计960个种群中，我们测定了种群密度与病毒敏感性的变化，并探究了细菌基因型间的差异是否可由其在无寄生病毒条件下的相对生长速率，或是针对每种噬菌体测得的噬菌体抗性突变率（通过波动试验（fluctuation tests）测定）所解释。研究发现，尽管部分抗生素耐药性等位基因（antibiotic-resistance alleles）会通过生长代价（growth costs）阻碍噬菌体抗性的进化，但抗生素耐药性对细菌适应噬菌体的整体影响相对较弱。与之相比，一项……