Use of Gallium to Prevent Pseudomonas Biofilm Formation

描述（由申请人提供）：生物膜的形成在由铜绿假单胞菌引起的急性和慢性肺部感染的发病机制中很重要，降低了宿主防御的有效性和细菌对抗生素杀伤的易感性。最近的证据表明，限制铁（Fe）的可用性可以阻止铜绿假单胞菌生物膜的形成，并增强其对妥布霉素的易感性。镓（Ca），一组IliA过渡金属破坏许多细胞类型的铁代谢。我们已经证明Ga抑制结核分枝杆菌的生长和铁的获取。基于这些和新的数据，我们假设Ga可以破坏P. aeruginosa铁的获取/代谢，从而破坏生物膜的形成并增强对常规抗生素的敏感性。它也可能限制浮游细菌的生长，浮游细菌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可能成为一种有效的治疗铜绿假单胞菌生物膜的药物。为了验证这些假设，我们将追求两个具体目标。首先，我们将确定Ga抑制P. aeruginosa生物膜形成的机制，并确定Ga是否增强了P. aeruginosa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对铜绿假单胞菌铁获取和铁依赖基因调控的影响。我们将直接测量P. aeruginosa对Fe和Ga的获取，并表征Ga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膜和由此引起的感染的方法。我们设想对铜绿假单胞菌感染的患者进行全身和/或雾化肺输送Ga和/或在通气患者的气管内灌注Ga以防止生物膜的形成。

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.