Fernandes Sheryl E, Ortega Humberto, Vaillancourt Mylene, Galdino Anna Clara M, Stotland Aleksandr, Mun Kyu Shik, Aguilar Diane, Doi Yohei, Lee Janet S, Burgener Elizabeth B, Barrick Jeffrey E, Schertzer Jeffrey W, Jorth Peter
Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Binghamton Biofilm Research Center, Department of Biological Sciences, Binghamton University, Binghamton, NY, USA.
Res Sq. 2024 Nov 12:rs.3.rs-5391023. doi: 10.21203/rs.3.rs-5391023/v1.
Antibiotic resistance is one of the most pressing threats to human health, yet recent work highlights how loss of resistance may also drive pathogenesis in some bacteria. In two recent studies, we found that β-lactam antibiotic and nutrient stresses faced during infection selected for the genetic inactivation of the () antibiotic efflux pump . Unexpectedly, efflux pump mutations increased virulence during infection; however, neither the prevalence of efflux pump inactivating mutations in real human infections, nor the mechanisms driving increased virulence of efflux pump mutants are known. We hypothesized that human infection would select for efflux pump mutations that drive increased virulence in clinical isolates. Using genome sequencing of hundreds of clinical isolates, we show that efflux pump inactivating mutations are enriched in cystic fibrosis isolates relative to intensive care unit clinical isolates. Combining RNA-seq, metabolomics, genetic approaches, and infection models we show that efflux pump mutants have elevated expression of two key virulence factors, elastase and rhamnolipids, which increased virulence and lung damage during both acute and chronic infections. Increased virulence factor production was driven by higher Pseudomonas quinolone signal levels in the efflux pump mutants. Finally, genetic restoration of the efflux pump in a representative ICU clinical isolate and the notorious CF Liverpool epidemic strain reduced their virulence. Together, our findings suggest that mutations inactivating antibiotic resistance mechanisms could lead to greater patient mortality and morbidity.
抗生素耐药性是对人类健康最紧迫的威胁之一，但最近的研究突出表明，耐药性的丧失在某些细菌中也可能推动发病机制。在最近的两项研究中，我们发现感染期间面临的β-内酰胺抗生素和营养压力会导致（）抗生素外排泵的基因失活。出乎意料的是，外排泵突变在感染期间增加了毒力；然而，在真实人类感染中外排泵失活突变的发生率以及驱动外排泵突变体毒力增加的机制均不为人所知。我们假设人类感染会选择导致临床分离株毒力增加的外排泵突变。通过对数百个临床分离株进行基因组测序，我们发现相对于重症监护病房临床分离株，囊性纤维化分离株中富集了外排泵失活突变。结合RNA测序、代谢组学、遗传学方法和感染模型，我们表明外排泵突变体中两种关键毒力因子弹性蛋白酶和鼠李糖脂的表达升高，这在急性和慢性感染期间均增加了毒力和肺损伤。外排泵突变体中较高的铜绿假单胞菌喹诺酮信号水平驱动了毒力因子产量的增加。最后，在一个具有代表性的重症监护病房临床分离株和臭名昭著的囊性纤维化利物浦流行菌株中对外排泵进行基因修复降低了它们的毒力。总之，我们的研究结果表明，使抗生素耐药机制失活的突变可能导致更高的患者死亡率和发病率。
