List of strains.

During chronic cystic fibrosis (CF) infections, evolved Pseudomonas aeruginosa antibiotic resistance is linked to increased pulmonary exacerbations, decreased lung function, and hospitalizations. However, the virulence mechanisms underlying worse outcomes caused by antibiotic resistant infections are poorly understood. Here, we investigated evolved aztreonam resistant P. aeruginosa virulence mechanisms. Using a macrophage infection model combined with genomic and transcriptomic analyses, we show that a compensatory mutation in the rne gene, encoding RNase E, increased pyoverdine and pyochelin siderophore gene expression, causing macrophage ferroptosis and lysis. We show that iron-bound pyochelin was sufficient to cause macrophage ferroptosis and lysis, however, apo-pyochelin, iron-bound pyoverdine, or apo-pyoverdine were insufficient to kill macrophages. Macrophage killing could be eliminated by treatment with the iron mimetic gallium. RNase E variants were abundant in clinical isolates, and CF sputum gene expression data show that clinical isolates phenocopied RNase E variant functions during macrophage infection. Together these data show how P. aeruginosa RNase E variants can cause host damage via increased siderophore production and host cell ferroptosis but may also be targets for gallium precision therapy.在慢性囊性纤维化（cystic fibrosis, CF）感染进程中，进化获得的铜绿假单胞菌（Pseudomonas aeruginosa）抗生素耐药性与肺部急性加重风险升高、肺功能下降及住院率增加显著相关。然而，抗生素耐药性感染引发不良临床结局的潜在毒力机制仍未得到充分阐释。本研究针对进化获得氨曲南（aztreonam）耐药性的铜绿假单胞菌毒力机制展开探究。借助巨噬细胞感染模型结合基因组与转录组分析，研究人员发现编码核糖核酸酶E（RNase E）的rne基因发生补偿性突变后，可上调绿脓菌素（pyoverdine）与吡咯菌素（pyochelin）两类嗜铁素的基因表达，进而诱导巨噬细胞铁死亡（ferroptosis）与裂解。实验证实，结合态铁的吡咯菌素即可单独诱导巨噬细胞铁死亡与裂解，而游离态吡咯菌素、结合态铁的绿脓菌素及游离态绿脓菌素均无法实现巨噬细胞杀伤。使用铁模拟剂镓（gallium）进行干预，即可消除该巨噬细胞杀伤效应。临床分离株中广泛存在核糖核酸酶E变异体，且囊性纤维化患者痰液转录组数据显示，临床分离株在巨噬细胞感染过程中可重现核糖核酸酶E变异体的功能表型。综上，本研究数据表明，铜绿假单胞菌的核糖核酸酶E变异体可通过提升嗜铁素产量、诱导宿主细胞铁死亡来造成宿主损伤，同时这类变异体也可作为镓精准治疗的潜在靶点。