The contribution of respiratory burst to antibiotic failure in Staphylococcus aureus bacteremia

摘要 众所周知，金黄色葡萄球菌感染很难用抗生素治疗。不像很多克- 阴性病原体，其中治疗失败的风险与抗生素的传播增加有关 抗性和泛抗性菌株的出现，S.金黄色葡萄球菌仍然很容易受到多种 抗生素然而，尽管有明显的易感性，这些抗生素治疗经常失败， 人死于S。2017年美国的金黄色葡萄球菌感染 S.金黄色葡萄球菌是装备精良的生存吞噬和巨噬细胞的吞噬溶酶体是 越来越多地被认为是S.金黄色葡萄球菌感染期间。我们发现，在一只老鼠身上， 系统感染模型，S.金黄色葡萄球菌不仅在巨噬细胞内存活， 在这个小环境中，它是一种耐受的、持久的状态，使其无法用抗生素治疗。 我们的总体假设是，巨噬细胞-S。金黄色葡萄球菌相互作用导致抗生素治疗失败， 患者 为了验证这一点，在目的1中，我们将使用临床S. 金黄色葡萄球菌分离株和患者匹配的巨噬细胞，从采集的外周血单核细胞中培养 万斯福勒医生的S.金黄色葡萄球菌菌血症组（SABG）。我们还将检查抗生素 组织培养中巨噬细胞的耐受诱导可以预测患者的结果。 在目标2中，我们将检查呼吸爆发是否也能够在体内产生抗生素抗性细胞。 组织培养和鼠菌血症模型。呼吸爆发产生的活性氧对呼吸的双重作用 诱导抗生素耐受性和诱变为抗生素的进化创造了理想的环境 感染时的抵抗力。 在目标3中，我们将研究2种治疗方法降低抗生素耐药性的潜力 巨噬细胞诱导。首先，我们将应用一系列抗氧化剂，包括最先进的方法 涉及将治疗剂特异性地靶向递送至巨噬细胞。其次，我们将导出M2 极化的巨噬细胞，以减少活性氧的产生，并提高抗生素的敏感性吞噬 S.金黄色。 总之，我们的建议有望解决S。金黄色葡萄球菌感染的鉴定 患者体内持久性形成的体内机制，检查它如何有助于抗生素耐药性 并确定治疗方法，以抑制持续存在的诱导，并改善 抗生素治疗

Summary Abstract Staphylococcus aureus infections are notoriously difficult to treat with antibiotics. Unlike many gram- negative pathogens where the risk of treatment failure is associated with the increasing spread of antibiotic resistance and the appearance of pan-resistant isolates, S. aureus remains largely susceptible to multiple antibiotics. However, despite apparent susceptibility, these antibiotic treatments frequently fail, and 20,000 people died from S. aureus infections in the U.S in 2017. S. aureus are well-equipped to survive phagocytosis and the phagolysosome of macrophages is increasingly appreciated as a major reservoir of S. aureus cells during infection. We find that, in a murine model of systemic infection, S. aureus not only survives within macrophages but also enters into a multidrug tolerant, persister state within this niche, rendering it untreatable with antibiotics. Our overall hypothesis is that macrophage-S. aureus interactions are driving antibiotic treatment failure in patients. To test this, in Aim 1, we will examine host macrophage induced antibiotic tolerance using clinical S. aureus isolates and patient matched macrophages, cultured from peripheral blood mononuclear cells taken from patients by Dr. Vance Fowler’s S. aureus bacteremia group (SABG). We will also examine if antibiotic tolerance induction by macrophages in tissue culture can predict patient outcomes. In Aim 2, we will examine if respiratory burst is also capable of generating antibiotic resistant cells in tissue culture and in a murine bacteremia model. The dual capacity of ROS produced by respiratory burst to induce antibiotic tolerance and mutagenesis creates an ideal environment for the evolution of antibiotic resistance during infection. In Aim 3, we will examine the potential of 2 therapeutic approaches to reduce antibiotic tolerance induction by macrophages. Firstly, we will apply a series of antioxidants, including a state-of the art approach involving the targeted delivery of therapeutics specifically to macrophages. Secondly, we will induce M2 polarization of macrophages to reduce ROS production and improve antibiotic susceptibility of phagocytosed S. aureus. In all, our proposal promises to address the problem of S. aureus infection recalcitrance by identifying the in vivo mechanism of persister formation in patients, examining how it contributes to antibiotic resistance and identifying therapeutic approaches to inhibit the induction of persisters and improve the outcome of antibiotic therapy.