Potentiating antibiotics against Campylobacter by inhibiting efflux

描述（申请人提供）：空肠弯曲杆菌是一种主要的肠道病原体，是世界上大量肠胃炎的罪魁祸首。弯曲杆菌病的临床治疗需要使用氟喹诺酮类或大环内酯类抗生素，但耐药弯曲杆菌日益普遍，影响了抗生素治疗的有效性。迫切需要新的策略来控制由耐药弯曲杆菌引起的感染。在弯曲杆菌产生抗生素耐药性的多种机制中，CmeABC多药外排泵是对多种抗菌素和有毒化合物产生耐药性的关键和主导因素。这种外排系统也在促进抗生素选择下敏感弯曲杆菌产生氟喹诺酮耐药突变体方面发挥重要作用。为了开发对抗耐药弯曲杆菌的新措施，我们已经开始研究利用反义肽核酸（PNA）靶向CmeABC的可行性。我们的初步结果表明，反义PNA方法具有很强的抑制cmeABC表达和使弯曲杆菌对抗生素敏感的潜力。在这个应用中，我们将进一步开发和评估反义PNA方法作为耐药弯曲杆菌的辅助治疗。R21期的具体目标是开发和评估抗cmeabc PNAs，有效增强抗生素对抗耐药弯曲杆菌的能力；R33期的具体目标是评估在动物模型中使用抗cmeabc PNAs作为对抗耐药弯曲杆菌的辅助疗法的可行性，确定PNAs在防止易感弯曲杆菌产生氟喹诺酮耐药突变体方面的效率。并通过修饰细胞穿透肽提高PNAs的通透性和稳定性。这项工作利用了一种新的靶点（CmeABC）和一种新的技术（反义PNA），并利用了体外和体内两种方法。一旦完成，该项目将开发出一种有效手段，以扩大现有抗生素对耐药弯曲杆菌的效用。此外，本项目建立的技术平台可以潜在地适用于其他抗生素耐药病原体。因此，这项工作不仅将显著推进抗生素耐药弯曲杆菌的新辅助疗法的发现，而且可能有益于其他病原体治疗的发展。

DESCRIPTION (provided by applicant): Campylobacter jejuni is a major enteric pathogen and is responsible for a large number of gastroenteritis worldwide. Clinical treatment of campylobacteriosis requires the use of fluoroquinolone or macrolide antibiotics, but antibiotic-resistant Campylobacter is increasingly prevalent, compromising the effectiveness of antibiotic therapy. Novel strategies are urgently needed to control infections caused by antibiotic-resistant Campylobacter. Among the various mechanisms utilized by Campylobacter for antibiotic resistance, the CmeABC multidrug efflux pump is a critical and predominant player in the resistance to a wide range of antimicrobials and toxic compounds. This efflux system also plays an important role in facilitating the emergence of fluoroquinolone-resistant mutants from susceptible Campylobacter under antibiotic selection. To develop novel measures to combat antibiotic-resistant Campylobacter, we have initiated studies to explore the feasibility of using antisense Peptide Nucleic Acid (PNA) to target CmeABC. Our preliminary result suggests that the antisense PNA approach has a strong potential to inhibit the expression of cmeABC and sensitize Campylobacter to antibiotics. In this application, we will further develop and evaluate the antisense PNA approach as an adjunctive therapy for antibiotic-resistant Campylobacter. The Specific aim for the R21 phase is to develop and evaluate anti-CmeABC PNAs that effectively potentiate antibiotics against antimicrobial-resistant Campylobacter and the specific aims for the R33 phase are to assess the feasibility of using anti-CmeABC PNAs as an adjunctive therapy to combat antibiotic-resistant Campylobacter in an animal model, determine the efficiency of PNAs in preventing the emergence of fluoroquinolone-resistant mutants from susceptible Campylobacter, and improve the permeability and stability of PNAs by modifying cell-penetrating peptides. The proposed work takes advantage of a novel target (CmeABC) and a novel technology (antisense PNA) and utilizes both in vitro and in vivo methodologies. Once completed, the project will have developed an effective mean to extend the utility of existing antibiotics against drug-resistant Campylobacter. Furthermore, the technical platform established in this project can be potentially adapted for other antibiotic-resistant pathogens. Thus the work will not only significantly advance the discovery of novel adjunctive therapies for antibiotic-resistant Campylobacter, but also potentially benefit the development of therapy for other pathogens.