The extensive use and misuse of antibiotics have resulted in bacterial resistance becoming increasing commonplace. Essential oils (EOs) are known to possess antimicrobial properties and therefore have many potential practical applications. However, the default of hydrophobicity, chemical instability, and volatility limit scope of application. Encapsulation of EOs in colloidal delivery systems can mitigate these challenges and allow for greater efficacy. A homogenous nanoemulsion (HS15-CE) containing a combination of eucalyptol (Euc) and cefradine (Cef) is developed to explore its synergistic effect on antibacterial activity and potentially reduce the amount of antibiotic required to treat bacterial infections. The HS15-CE nanoemulsion displays a synergistic effect on the inhibition of Escherichia coli (E. coli) growth in vitro, significantly decreasing the minimum inhibitory concentration (MIC) by eight times. The ex vivo imaging reveals high accumulation concentrations and long retention in bladders. Moreover, the nanoemulsion alleviates the E. coli induced cystitis infection, as evidenced by decreased bacterial colonies in urine, reduced inflammatory cytokines, and increased expression of tight junctional protein ZO-1. These findings suggest the potential of the HS15-CE nanoemulsion in providing a synergistic effect for the treatment of bacterial urocystitis.

中文翻译：

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抗生素和桉油精的多功能纳米乳剂对大肠杆菌感染的尿囊炎具有协同作用

抗生素的广泛使用和滥用导致细菌耐药性变得越来越普遍。众所周知，精油 (EO) 具有抗菌特性，因此具有许多潜在的实际应用。然而，疏水性、化学不稳定性和挥发性的默认限制了应用范围。将环氧乙烷封装在胶体递送系统中可以缓解这些挑战并提高功效。开发了一种含有桉树脑 (Euc) 和头孢拉定 (Cef) 组合的均质纳米乳剂 (HS15-CE)，以探索其对抗菌活性的协同作用，并可能减少治疗细菌感染所需的抗生素用量。HS15-CE纳米乳在体外对抑制大肠杆菌（E. coli）生长表现出协同作用，使最低抑菌浓度（MIC）显着降低8倍。离体成像显示其在膀胱中的积累浓度高且滞留时间长。此外，纳米乳剂还可以减轻大肠杆菌引起的膀胱炎感染，尿液中细菌菌落减少、炎症细胞因子减少以及紧密连接蛋白 ZO-1 表达增加就证明了这一点。这些发现表明 HS15-CE 纳米乳在治疗细菌性尿囊炎方面具有协同作用的潜力。