Multidrug-resistant (MDR) Staphylococcus aureus is a major cause of biofilm-associated and indwelling device related infections. The present study explores the anti-virulent and antibiofilm potency of chitosan extracted from the shells of the marine crab Portunus sanguinolentus against Methicillin Resistant Staphylococcus aureus (MRSA). The chemical characterization results revealed that the extracted chitosan (EC) has structural analogy to that of a commercial chitosan (CC). The extracted chitosan was found to be effective in reducing the staphyloxanthin pigment, a characteristic virulence feature of MRSA that promotes resistance to reactive oxygen species. Furthermore, Confocal laser scanning microscope (CLSM) revealed that EC exhibited a phenomenal dose dependent antibiofilm efficacy against mature biofilms of the standard as well as clinical MRSA strains and Scanning Electron Microscopy (SEM) confirmed EC had a higher efficacy in disrupting the thick Exopolysaccharide (EPS) layer than CC. Additionally, EC and CC did not have any cytotoxic effects when tested on lung epithelial cell lines. Thus, the study exemplifies the anti-virulent properties of a marine bioresource which is till date discarded as a biowaste.

耐多药（MDR）金黄色葡萄球菌是生物膜相关和留置装置相关感染的主要原因。本研究探讨了从海洋蟹Portunus sanguinolentus的贝壳中提取的壳聚糖对耐甲氧西林金黄色葡萄球菌（MRSA）的抗毒力和抗生物膜的能力。化学表征结果表明，提取的壳聚糖（EC）具有与商用壳聚糖（CC）相似的结构。发现提取的壳聚糖可有效减少葡萄黄素的色素，葡萄黄素的色素具有MRSA的特征性毒力，可增强对活性氧的抵抗力。此外，共聚焦激光扫描显微镜（CLSM）显示EC对标准和临床MRSA菌株的成熟生物膜表现出显着的剂量依赖性抗生物膜功效，并且扫描电子显微镜（SEM）证实EC在破坏厚厚的胞外多糖（EPS）方面具有更高的功效。层比CC。另外，当在肺上皮细胞系上测试时，EC和CC没有任何细胞毒性作用。因此，该研究举例说明了海洋生物资源的抗毒特性，该生物资源迄今为止一直作为生物废物被丢弃。