摘要

当细菌对特定抗生素产生抗性时，它们可能同时获得对第二种敏感性的增加的敏感性。这种附带敏感性可用于开发新型，可持续的抗生素治疗策略，旨在遏制当前耐药性的巨大扩散。迄今为止，仅在少数细菌种类中研究了侧支敏感性的存在和分子基础，并且对机会性人类病原体如铜绿假单胞菌（Pseudomonas aeruginosa）未知。在本研究中，我们通过实验性地发展了160个独立的铜绿假单胞菌群，对8种常用抗生素的高度耐药性评估了副作用的模式。细菌迅速产生抗性并表现出副作用敏感性和交叉耐药性。这种间接影响的模式不同于之前报道的其他细菌物种的模式，表明潜在的演化平衡的种间差异。有意思的是，我们还确定了适用于相同药物的重复群体间侧枝敏感性和交叉抗性的对比模式。 81个独立进化群体的全基因组测序揭示了对选择性药物具有不同进化途径的进化路径，这决定了细菌是否对其他细菌产生交叉抗性或附带地敏感。基于基因组和功能性遗传分析，我们证明侧支敏感性可能来自调节基因中的抗性突变，例如调节β-内酰胺适应群体中氨基糖苷类敏感性的nalC或mexZ或双组分调控系统基因pmrB，其中增强庆大霉素耐药菌群对青霉素的敏感性。我们的研究结果突出显示重复间进展副作用的实质性差异，这反过来决定了他们在抗生素治疗中的潜力。

When bacteria evolve resistance against a particular antibiotic, they may simultaneously gain increased sensitivity against a second one. Such collateral sensitivity may be exploited to develop novel, sustainable antibiotic treatment strategies aimed at containing the current, dramatic spread of drug resistance. To date, the presence and molecular basis of collateral sensitivity has only been studied in few bacterial species and is unknown for opportunistic human pathogens such as Pseudomonas aeruginosa. In the present study, we assessed patterns of collateral effects by experimentally evolving 160 independent populations of P. aeruginosa to high levels of resistance against eight commonly used antibiotics. The bacteria evolved resistance rapidly and expressed both collateral sensitivity and cross-resistance. The pattern of such collateral effects differed to those previously reported for other bacterial species, suggesting interspecific differences in the underlying evolutionary trade-offs. Intriguingly, we also identified contrasting patterns of collateral sensitivity and cross-resistance among the replicate populations adapted to the same drug. Whole-genome sequencing of 81 independently evolved populations revealed distinct evolutionary paths of resistance to the selective drug, which determined whether bacteria became cross-resistant or collaterally sensitive towards others. Based on genomic and functional genetic analysis, we demonstrate that collateral sensitivity can result from resistance mutations in regulatory genes such as nalC or mexZ, which mediate aminoglycoside sensitivity in β-lactam-adapted populations, or the two-component regulatory system gene pmrB, which enhances penicillin sensitivity in gentamicin-resistant populations. Our findings highlight substantial variation in the evolved collateral effects among replicates, which in turn determine their potential in antibiotic therapy.

https://academic.oup.com/mbe/article/34/9/2229/3829862