Use of Gallium to Prevent Pseudomonas Biofilm Formation

描述(由申请人提供)：生物膜的形成在铜绿假单胞菌引起的急性和慢性肺部感染的发病机制中非常重要，它降低了宿主防御的有效性和细菌对抗生素的敏感性。最近的证据表明，限制铁(Fe)的有效性可以防止铜绿假单胞菌生物被膜的形成，并增强其对妥布霉素的敏感性。镓(Ca)是一类过渡金属，可干扰许多细胞类型的铁代谢。结果表明，Ga对结核分枝杆菌的生长和铁的吸收有抑制作用。基于这些和新的数据，我们假设GA可以扰乱铜绿假单胞菌铁的获取/代谢，从而扰乱生物膜的形成，并增加对常规抗生素的敏感性。它还可能限制浮游细菌的生长，使其与铜绿假单胞菌感染部位的生物膜处于动态平衡状态。因此，GA有可能成为治疗铜绿假单胞菌生物被膜的有效药物。为了检验这些假设，我们将追求两个具体目标。首先，我们将确认和定义GA抑制铜绿假单胞菌生物被膜形成的机制，并确定GA是否增强了铜绿假单胞菌对常规抗生素的敏感性。这将使用两个体外铜绿假单胞菌生物膜模型来完成。其次，我们将确定GA对铜绿假单胞菌铁的获取和铁依赖的基因调控的影响。我们将直接测量铜绿假单胞菌对铁和镓的获取，以及表征镓与其铁载体的相互作用。DNA微阵列技术将用于研究GA对铜绿假单胞菌基因调控的影响。这项工作的长期目标是开发一种利用GA预防和/或治疗铜绿假单胞菌生物被膜及其引起的感染的方法。我们将设想全身和/或雾化吸入镓给铜绿假单胞菌感染的患者和/或将镓浸入气管内，以防止机械通气患者的生物被膜形成。

DESCRIPTION (provided by applicant): Biofilm formation is important in the pathogenesis of acute and chronic infections of the lung by Pseudomonas aeruginosa, decreasing the effectiveness of host defenses and bacterial susceptibility to killing by antibiotics. Recent evidence shows that limiting iron (Fe) availability prevents P. aeruginosa biofilm formation and enhances its susceptibility to tobramycin. Gallium (Ca), a group IliA transition metal disrupts the Fe metabolism of many cell types. We have shown that Ga inhibits the growth and Fe acquisition by Mycobacterium tuberculosis. Based on these and new data, we hypothesize that Ga can disrupt P. aeruginosa Fe acquisition/metabolism, thereby disrupting biofilm formation and enhancing susceptibility to conventional antibiotics. It may also limit the growth of planktonic bacteria that would be in dynamic equilibrium with the biofilm at sites of P. aeruginosa infection. Thus, Ga could become a potent therapy against P. aeruginosa biofilms. To test these hypotheses, two specific aims will be pursued. First, we will confirm and define the mechanism whereby Ga inhibits P. aeruginosa biofilm formation and ascertain if Ga enhances the susceptibility of P. aeruginosa to conventional antibiotics. This will be done using two in vitro P. aeruginosa biofilm models. Second, we will determine the effect of Ga on P. aeruginosa Fe acquisition and Fe-dependent gene regulation. We will directly measure Fe and Ga acquisition by P. aeruginosa, as well as characterize the interaction of Ga with its siderophores. DNA microarray technology will be used to study the impact of Ga on P. aeruginosa gene regulation. The long-term goal of this work is to develop a means to utilize Ga for the prevention and/or treatment of P. aeruginosa biofilms and the infections that result. We would envision the systemic and/or aerosolized pulmonary delivery of Ga to P. aeruginosa-infected patients and/or impregnating endotracheal tubes with Ga to prevent biofilm formation in ventilated patients.