Kim H W, Chung D H, Kim S A, Rhee M S
Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
Department of Food Science and Engineering, Ewha Womans University, Seoul, Republic of Korea.
Lett Appl Microbiol. 2019 Apr;68(4):321-328. doi: 10.1111/lam.13140. Epub 2019 Mar 13.
Urinary tract infections (UTI), one of the most common diseases in humans, are caused primarily by uropathogenic Escherichia coli (UPEC). Cranberry juice (CB) is a widely known prophylaxis for UTI, but the treatment of CB alone could not effectively eradicate preformed UPEC biofilms. The aim of this study was to develop enforced CB composites within a short time by adding a small quantity of natural borne antimicrobials. UPEC biofilms (initial: 6·0 log CFU per cm ), formed on silicone coupons in artificial urine medium, were exposed to CB (4-8%), caprylic acid (CAR; 0·025-0·05%) and thymol (TM; 0·025-0·05%) at 37°C for 1 min. Individual treatment of each compound did not show the significant antibacterial effect on UPEC biofilms (P > 0·05). Otherwise, the survivor counts of biofilms were synergistically reduced with CB containing any of the antimicrobials. For example combined treatment with CB (8%) + CAR (0·05%) + TM (0·05%) resulted in a 6 log reduction in UPEC populations in the biofilm (no detectable bacteria remained) with 4·6 log of synergistic bactericidal effect. The confocal laser scanning microscope images indicated that any composites including TM might result in biofilm detachment from the surface. The present method is cost-effective and more acceptable to consumers as it is based on the synergistic interaction of natural borne antimicrobials. The results of this study could be widely applicable in the functional food, medical and healthcare field. SIGNIFICANCE AND IMPACT OF THE STUDY: Anti-biofilm effect of cranberry juice (CB) has been focused mainly on inhibiting biofilm formation of uropathogenic Escherichia coli (UPEC); however, combined treatment with natural borne antimicrobials derived from coconut oil (caprylic acid) and oregano essential oil (thymol) could synergistically enhance its eradicating activity against biofilms. This study developed novel CB composites showing marked anti-biofilm effects (complete eradication of UPEC biofilms within just 1 min).
尿路感染（UTI）是人类最常见的疾病之一，主要由尿路致病性大肠杆菌（UPEC）引起。蔓越莓汁（CB）是一种广为人知的UTI预防剂，但单独使用CB治疗无法有效根除预先形成的UPEC生物膜。本研究的目的是通过添加少量天然抗菌剂在短时间内开发强化CB复合材料。在人工尿液培养基中硅胶试片上形成的UPEC生物膜（初始：每平方厘米6.0 log CFU），在37°C下暴露于CB（4 - 8%）、辛酸（CAR；0.025 - 0.05%）和百里香酚（TM；0.025 - 0.05%）1分钟。每种化合物单独处理对UPEC生物膜均未显示出显著的抗菌效果（P > 0.05）。否则，含有任何一种抗菌剂的CB可协同降低生物膜的存活菌数。例如，CB（8%） + CAR（0.05%） + TM（0.05%）联合处理导致生物膜中UPEC数量减少6 log（无检测到的细菌残留），具有4.6 log的协同杀菌效果。共聚焦激光扫描显微镜图像表明，任何包含TM的复合材料都可能导致生物膜从表面脱落。本方法具有成本效益且更易为消费者接受，因为它基于天然抗菌剂的协同相互作用。本研究结果可广泛应用于功能性食品、医学和医疗保健领域。研究的意义和影响：蔓越莓汁（CB）的抗生物膜作用主要集中在抑制尿路致病性大肠杆菌（UPEC）生物膜的形成；然而，与源自椰子油的天然抗菌剂（辛酸）和牛至精油（百里香酚）联合处理可协同增强其对生物膜的根除活性。本研究开发出了具有显著抗生物膜效果（仅1分钟内完全根除UPEC生物膜）的新型CB复合材料。
