Data from: 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 mutator allele,
often found in antibiotic-resistant lineages in pathogenic populations,
had a relatively large positive effect on phage-resistance evolution and
population density under parasitism. This suggests costs of antibiotic
resistance may modify the outcome of phage therapy against pathogenic
populations previously exposed to antibiotics, but the effects of any
co-occurring mutator alleles are likely to be stronger.

抗生素耐药性对细菌表型与进化具有广泛影响。然而，尽管寄生病毒在自然界中无处不在且当前在治疗应用中备受关注，抗生素耐药性对细菌应对寄生病毒的反应所产生的影响仍不明晰。本研究通过将多种大肠杆菌（Escherichia coli）基因型（涵盖8种抗生素耐药基因型与1株增变菌株）暴露于不同裂解性噬菌体（lytic bacteriophages）中，对该问题开展了实验探究。我们在960个种群中测定了种群密度与病毒敏感性的变化，并检验了细菌基因型间的差异是否可通过其在无寄生条件下的相对生长速率，或是通过针对每种噬菌体的波动试验（fluctuation tests）测得的噬菌体耐药性突变率来解释。研究发现，尽管部分抗生素耐药等位基因会通过生长代价阻碍细菌演化出噬菌体耐药性，但抗生素耐药性对细菌适应噬菌体的影响相对较弱。与之形成鲜明对比的是，常在致病种群的抗生素耐药谱系中被检测到的增变基因等位基因，对寄生条件下的噬菌体耐药性演化与种群密度均具有显著的正向影响。这表明，抗生素耐药性的代价或许会改变曾暴露于抗生素的致病种群接受噬菌体疗法的结局，但同时存在的增变基因等位基因所带来的影响可能更为显著。