Deciphering the impact of sedative choice on the dynamics of Klebsiella pneumoniae lung infection

总结 医疗保健相关感染会对患者的治疗结果产生不利影响，并使医疗保健成本增加数十亿美元 每年 美元。麻醉给药与感染风险显着增加相关 它改变免疫信号和免疫效应细胞功能。尽管人们越来越认识到 麻醉剂调节免疫力，但关于其机制的广度仍知之甚少。 针对神经系统的药物会影响宿主的免疫反应。我们之前已经证明了 使用异丙酚（最常用的麻醉诱导药物）进行短暂镇静可显着增加宿主 对微生物感染的易感性。异丙酚广泛用于需要插管和机械治疗的患者 通气，ICU 中的患者可以使用异丙酚保持镇静数天。为了更好地定义影响 异丙酚镇静治疗呼吸道疾病，我们使用革兰氏阴性菌开发了肺部感染的小鼠模型 阴性机会致病菌肺炎克雷伯菌 (Kp)。 Kp 在全球范围内是一个日益严重的威胁 由于其快速获得抗菌药物耐药性而导致院内病原体；此外，高毒力菌株 最近有报道称其导致社区获得性感染。初步实验表明 异丙酚镇静显着增加肺部 Kp 疾病病理的严重程度并促进 细菌传播到远端组织。使用转座子插入测序 (INSeq) 和 Kp 文库 插入突变体，我们进一步证明镇静剂的选择影响 Kp 的选择 在受感染的肺内生长有缺陷的突变体。这些结果强烈表明异丙酚不 仅影响肺部感染的病理学和结果，但它也对肺部感染的武库产生不同的影响 疾病所需的细菌毒力因子。因此，该提案旨在探索两个相关且 相互重要的假设，即 (1) 异丙酚增加宿主对微生物 (Kp) 的敏感性 通过免疫信号的改变而导致肺部感染，从而干扰先天免疫细胞的募集和功能 免疫效应细胞； (2) 镇静剂的选择会改变肺部环境，从而影响 Kp 细菌在组织中生长所需的整体毒力库。目标 1 实验将确定如何 镇静选择影响体内 Kp 肺部感染的结果和进展。目标 2 将在功能上 描述了根据其毒力受到镇静作用的不同影响而鉴定的 Kp 突变体的特征 异丙酚与氯胺酮/甲苯噻嗪。总的来说，这些实验将提供有价值且重要的信息 关于镇静对呼吸道感染结果和预后的影响。

Summary Healthcare-associated infections adversely impact patient outcomes and increase healthcare costs by billions of dollars each year. Anesthetic administration is associated with a significantly increased risk of infection via its alterations of immune signaling and immune effector cell function. Despite the increasing recognition that anesthetics modulate immunity, relatively little remains known regarding the breadth of mechanisms by which drugs that target the nervous system influence host immune responses. We have previously demonstrated that brief sedation with propofol, the most commonly used drug for anesthetic induction, dramatically increases host susceptibility to microbial infection. Propofol is widely used for patients requiring intubation and mechanical ventilation, and patients in the ICU can remain sedated with propofol for days. To better define the impact of propofol sedation on respiratory disease, we have developed a mouse model of lung infection using the Gram- negative opportunistic pathogen Klebsiella pneumoniae (Kp). Kp is a growing threat worldwide as a nosocomial pathogen due to its rapid acquisition of antimicrobial resistance; in addition, hypervirulent strains causing community-acquired infections have been recently reported. Preliminary experiments indicate that propofol sedation dramatically increases the severity of Kp disease pathology within the lungs and promotes bacterial dissemination to distal tissues. Using transposon insertion sequencing (INSeq) and libraries of Kp insertion mutants, we have further demonstrated that the choice of sedative influences the selection of Kp mutants that are defective for growth within the infected lung. These results strongly suggest that propofol not only influences the pathology and outcome of lung infection, but that it also differentially impacts the arsenal of bacterial virulence factors required for disease. This proposal is thus designed to explore two related and mutually important hypotheses, those being (1) that propofol increases host susceptibility to microbial (Kp) infection in the lung via alterations in immune signaling that interfere with the recruitment and function of innate immune effector cells; and (2) the choice of sedation alters the lung environment in ways that impact the Kp global virulence repertoire required for bacterial growth in tissues. Aim 1 experiments will determine how sedation choice influences the outcome and progression of Kp lung infection in vivo. Aim 2 will functionally characterize Kp mutants identified based on their virulence being differentially impacted by sedation with propofol versus ketamine/xylazine. Overall, these experiments will provide valuable and important information regarding the impact of sedation on respiratory infection outcome and prognosis.