Biofilms are surface-associated microbial communities embedded in a matrix that is almost impenetrable to antibiotics, thus constituting a critical health threat. Biofilm formation on the cornea or ocular devices can lead to serious and difficult-to-treat infections. Nowadays, natural molecules with antimicrobial activity and liposome-based delivery systems are proposed as anti-biofilm candidates. In this study, the anti-biofilm activity of a formulation containing citrus polyphenols encapsulated in liposomes was evaluated against Staphylococcus aureus and Staphylococcus epidermidis, the most common agents in ocular infections. The formulation activity against planktonic staphylococci was tested by broth microdilution and sub-inhibitory concentrations were used to evaluate the effect on biofilm formation using the crystal violet (CV) assay. The eradicating effect of the preparation on mature biofilms was investigated by the CV assay, plate count, and confocal laser scanning microscopy. The product was bactericidal against staphylococci at a dilution of 1:2 or 1:4 and able to reduce biofilm formation even if diluted at 1:64. The formulation also had the ability to reduce the biomass of mature biofilms without affecting the number of cells, suggesting activity on the extracellular matrix. Overall, our results support the application of the used liposome-encapsulated polyphenols as an anti-biofilm strategy to counter biofilm-associated ocular infections.

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含有柑橘多酚的脂质体制剂的抗葡萄球菌生物膜作用

生物膜是嵌入基质中的与表面相关的微生物群落，抗生素几乎无法渗透，因此构成了严重的健康威胁。角膜或眼科设备上的生物膜形成可能导致严重且难以治疗的感染。如今，具有抗菌活性的天然分子和基于脂质体的递送系统被提议作为抗生物膜的候选者。在这项研究中，评估了脂质体中含有柑橘多酚的制剂对金黄色葡萄球菌和表皮葡萄球菌（眼部感染中最常见的病原体）的抗生物膜活性。通过微量肉汤稀释测试制剂对浮游葡萄球菌的活性，并使用亚抑制浓度通过结晶紫（CV）测定评估对生物膜形成的影响。通过CV测定、平板计数和共焦激光扫描显微镜研究了制剂对成熟生物膜的根除效果。该产品在 1:2 或 1:4 的稀释度下对葡萄球菌具有杀菌作用，即使在 1:64 的稀释度下也能减少生物膜的形成。该制剂还能够减少成熟生物膜的生物量而不影响细胞数量，这表明对细胞外基质的活性。总的来说，我们的结果支持使用脂质体封装的多酚作为抗生物膜策略来对抗生物膜相关的眼部感染。