Compared to mono-species biofilm, biofilms formed by cross-kingdom pathogens are more refractory to conventional antibiotics, thus complicating clinical treatment and causing significant morbidity. Lemongrass essential oil and its bioactive component citral were previously demonstrated to possess strong antimicrobial efficacy against pathogenic bacteria and fungi. However, their effects on polymicrobial biofilms remain to be determined. In this study, the efficacy of lemongrass (Cymbopogon flexuosus) essential oil and its bioactive part citral against dual-species biofilms formed by Staphylococcus aureus and Candida species was evaluated in vitro. Biofilm staining and viability test showed both lemongrass essential oil and citral were able to reduce biofilm biomass and cell viability of each species in the biofilm. Microscopic examinations showed these agents interfered with adhesive characteristics of each species and disrupted biofilm matrix through counteracting nucleic acids, proteins and carbohydrates in the biofilm. Moreover, transcriptional analyses indicated citral downregulated hyphal adhesins and virulent factors of Candida albicans, while also reducing expression of genes involved in quorum sensing, peptidoglycan and fatty acids biosynthesis of S. aureus. Taken together, our results demonstrate the potential of lemongrass essential oil and citral as promising agents against polymicrobial biofilms as well as the underlying mechanisms of their activity in this setting.

与单物种生物膜相比，跨王国病原体形成的生物膜对常规抗生素更难治，因此使临床治疗变得复杂，并导致大量发病。柠檬草精油及其柠檬酸的生物活性成分先前已被证明对病原细菌和真菌具有强大的抗菌功效。然而，它们对微生物生物膜的影响仍有待确定。在这项研究中，柠檬草的功效（弯腰柏）精油及其生物活性部分对由以下物质形成的双物种生物膜具有保护作用 金黄色葡萄球菌 和 念珠菌属 物种进行了评估 体外。生物膜染色和生存力测试表明，柠檬草精油和柠檬醛均能够降低生物膜中每种物种的生物膜生物量和细胞生存力。显微镜检查表明，这些试剂通过抵消生物膜中的核酸，蛋白质和碳水化合物，干扰了每个物种的粘附特性并破坏了生物膜基质。此外，转录分析表明柠檬醛下调菌丝粘附素和强毒因子白色念珠菌，同时也减少了涉及群体感应，肽聚糖和脂肪酸生物合成的基因的表达 金黄色葡萄球菌。两者合计，我们的结果表明柠檬草精油和柠檬醛作为抗微生物微生物生物膜的有前途的代理商的潜力，以及在这种情况下其活性的潜在机制。