The effect of environmental heterogeneity on the fitness of antibiotic resistance mutations in Escherichia coli

Antimicrobial resistance (AMR) is widespread, with resistant pathogens found not only in the clinic but throughout the natural and built environments. It is unclear, however, to what extent AMR should be expected to persist in the environment: Laboratory experiments have suggested that resistance is typically costly, and hence should be selected against. However, such studies may not generalize to broader environmental settings. As such, we estimated the fitness of six AMR mutants of Escherichia coli in ten media reflecting ecological niches, human hosts, and standard lab conditions. We found extensive evidence for genotype x environment interactions, with different genotypes favored in different environments. Resistance alleles did not suffer a cost in some environments, raising the possibility of environmental reservoirs of resistance. Interestingly, fitness tended to be higher in lower quality environments. Our findings emphasize the need to consider the ecology and evolution of resi...

抗菌药物耐药性（Antimicrobial Resistance，AMR）分布广泛，耐药病原体不仅存在于临床环境中，还遍布自然与人工构建环境。然而，目前尚不清楚AMR在环境中能持续存在到何种程度：实验室实验表明，耐药性通常会带来适应性代价，因此应受到负向选择。但这类研究的结论可能无法推广至更广泛的环境场景。为此，我们评估了大肠杆菌（Escherichia coli）的6种AMR突变株在10种培养基中的适应性——这些培养基分别模拟了生态位、人类宿主环境及标准实验室条件。我们发现了大量基因型-环境互作（genotype x environment interactions）的证据，不同环境中会有不同基因型被优先选择。在某些环境中，耐药等位基因并未表现出适应性代价，这提示了耐药性环境储库存在的可能性。有趣的是，在质量较低的环境中，适应性往往更高。我们的研究结果强调，需将耐药性的生态学与进化过程纳入考...