Antibiotics for Recalcitrant Infection

描述（由申请人提供）：该项目的目标是开发一种能够对顽固性慢性感染（如深部脓肿、骨髓炎、心内膜炎和留置器械生物膜）进行灭菌的治疗药物。这些感染中的许多基本上是无法治疗的，并导致大量的发病率和死亡率。在许多情况下，感染的复发不是由耐药性引起的。相反，缓慢生长的生物膜群体具有稳定期和休眠的持留细胞，这些细胞对抗微生物剂的杀灭具有高度耐受性。 当抗生素浓度下降时，这些细胞可以生长并重新填充生物膜。在革兰氏阳性S.对于金黄色葡萄球菌，似乎静止培养物主要由耐药细胞组成，这些耐药细胞实际上对传统抗生素的杀伤不敏感。存在许多独立的、冗余的持续形成机制，并且这些特化的存活细胞没有可用于药物开发的现实靶点。为了发挥作用，所有现有的杀菌抗生素都需要它们破坏的活性靶标。我们推断，如果一个小分子可以同时激活和破坏一个细胞靶点，那么坚持者就可以被杀死。我们发现，酰基缩酚酸肽（ADEP）激活ClpP蛋白酶在休眠persisters，迫使细胞自我消化。为了减少耐药性的发展，ADEP与利福平联合使用。这种组合完全消灭了深层的生物膜感染的沙门氏菌。金黄色葡萄球菌在单次给药后在血小板减少小鼠模型中的表达。最好的传统抗生素，单独或联合使用，效果甚微。该模型模拟了免疫功能低下患者中最难治疗的慢性感染。在这个项目中，我们将确定最有前途的杀菌药物组合。将使用MRSA感染的深位阴茎海绵体大腿模型和体内生物膜组织笼模型评价联合给药的PK、PD和疗效。一旦得到验证，该组合治疗剂将进入II期临床前研究，导致IND和随后的药物临床试验。

DESCRIPTION (provided by applicant): The goal of the project is to develop a therapeutic capable of sterilizing recalcitrant chronic infections such as deep-seated abscess, osteomyelitis, endocarditis, and biofilms of indwelling devices. Many of these infections are essentially untreatable and lead to substantial morbidity and mortality. In many cases, recalcitrance of an infection is not caused by drug resistance. Rather, a slow-growing biofilm population harbors stationary phase and dormant persister cells that are highly tolerant to killing by antimicrobials. When antibiotic concentration drops, these cells can grow and repopulate the biofilm. In Gram-positive S. aureus, it appears that a stationary culture is made mostly of drug tolerant cells which are virtually insensitive to killing by traditional antibiotics. There are many independent, redundant mechanisms of persister formation, and these specialized survivor cells do not have a realistic target which could be exploited for drug development. In order to act, all existing bactericidal antibiotics require active targets which they corrupt. We reasoned that persisters could be killed if a small molecule could simultaneously activate and corrupt a cellular target. We find that acyldepsipeptide (ADEP) activates the ClpP protease in dormant persisters, forcing the cell to self-digest. In order to diminish resistance development, ADEP was combined with rifampicin. The combination completely sterilized a deep- seated biofilm infection of S. aureus in a neutropenic mouse model after a single dose. The best conventional antibiotics, alone or in combination, had very little effect. This model emulates the most difficult to treat chronic infection in immunocompromised patients. In this project, we will identify the most promising sterilizing combinations of drugs. Combinations will be evaluated for PK, PD, and efficacy using a deep-seated neutropenic thigh model of MRSA infection, and in an in vivo biofilm tissue-cage model. Once validated, the combination therapeutic will enter into preclinical investigation in Phase II, leading to an IND, and subsequent clinical trials of the drug.