Biofilm Biology Laboratory, Centre for Research on Infectious Diseases (CRID), School of Chemical and Biotechnology, SASTRA Deemed University, Tirumalaisamudram, Thanjavur 613401,Tamil Nadu, India.
Department of Pharmacy, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India.
Pathog Dis. 2019 Feb 1;77(1). doi: 10.1093/femspd/ftz009.
Quorum sensing (QS) plays an important role during the aetiology of urinary tract infection (UTI), as several virulence factors are under the regulation of QS. Pseudomonas aeruginosa and Serratia marcescens, the primary causative agents of UTI, employ acyl homoserine lactone (AHL) as signal molecules to coordinate various virulence factors. In this present study, chitosan extracted from the marine crab Portunus sanguinolentus was screened for its ability to inhibit the QS-signaling molecules of P. aeruginosa (PA01) and few clinical isolates of P. aeruginosa and S. marcescens. The extracted chitosan on comparison with a commercial chitosan showed significant inhibition of several QS-dependent virulence factors in P. aeruginosa and S. marscenes. Furthermore, qPCR analysis was carried out to confirm the down-regulation of fimA, fimC and flhD genes involved in adhesion and pathogenesis of S. marcescens and lasI and rhlI genes that governs the P. aeruginosa quorum sensing system. Moreover, the chitosan when coated on a catheter was also able to disrupt the mature biofilms which was revealed by scanning electron microscopy. Collectively, the present study showcases the QS inhibitory property of extracted chitosan from crab shells which is being discarded as a recalcitrant biowaste.
群体感应（QS）在尿路感染（UTI）的病因学中起着重要作用，因为几种毒力因子受 QS 的调节。铜绿假单胞菌和粘质沙雷氏菌是 UTI 的主要病原体，它们使用酰基高丝氨酸内酯（AHL）作为信号分子来协调各种毒力因子。在本研究中，从海洋蟹 Portunus sanguinolentus 中提取的壳聚糖被筛选出来，以抑制铜绿假单胞菌（PA01）和一些临床分离株的 QS 信号分子。与商业壳聚糖相比，提取的壳聚糖显著抑制了铜绿假单胞菌和粘质沙雷氏菌的几种 QS 依赖性毒力因子。此外，还进行了 qPCR 分析，以确认参与粘质沙雷氏菌粘附和发病机制的 fimA、fimC 和 flhD 基因以及调节铜绿假单胞菌群体感应系统的 lasI 和 rhlI 基因的下调。此外，壳聚糖涂覆在导管上也能够破坏成熟的生物膜，这一点通过扫描电子显微镜得到了证实。总之，本研究展示了从蟹壳中提取的壳聚糖的 QS 抑制特性，这些壳聚糖被作为难生物降解的生物废物丢弃。
