Ortho-Substituted α‑Phenyl Mannoside Derivatives Promoted Early-Stage Adhesion and Biofilm Formation of <i>E. coli</i> 83972

Prevention of catheter-associated urinary tract infection (CAUTI) over long-term usage of urinary catheters remains a great challenge. Bacterial interference using nonpathogenic bacteria, such as E. coli 83972, have been investigated in many pilot-scale clinical studies as a potentially nonantibiotic based strategy for CAUTI prevention. We have demonstrated that preforming a dense and stable biofilm of the nonpathogenic E. coli greatly enhances their capability to prevent pathogen colonization. Such nonpathogenic biofilms were formed by E. coli 83972 expressing type 1 fimbriae (fim+ E. coli 83972) on mannoside-presenting surfaces. In this work, we report the synthesis of a series of mannoside derivatives with a wide range of binding affinities, all being equipped with a handle for covalent attachment to silicone surfaces. We established a high-throughput competitive assay based on mannoside-modified particles and flow-cytometry to directly measure the binding affinity between the mannoside ligands and fim+ E. coli 83972. We demonstrated that the bacterial adhesion and biofilm formation were strongly correlated to the binding affinity of the immobilized mannoside ligands. Mass spectrometry based proteomic analysis indicated a substantial difference in the proteome of the extracellular polymeric substance (EPS) secreted by biofilms on different mannoside surfaces, which might be related to the biofilm stability.长期留置导尿管过程中，预防导尿管相关尿路感染（catheter-associated urinary tract infection, CAUTI）仍是一项重大挑战。诸多试点临床研究已探索以非致病性细菌（如大肠杆菌（E. coli）83972）开展细菌干扰法，作为预防CAUTI的潜在非抗生素策略。本团队此前已证实，构建致密且稳定的非致病性大肠杆菌生物膜，可显著提升其抵御病原菌定植的能力。此类非致病性生物膜由表达1型菌毛（type 1 fimbriae）的大肠杆菌83972（fim+ 大肠杆菌83972）在甘露糖苷（mannoside）修饰表面形成。本研究中，我们合成了一系列具有宽泛结合亲和力范围的甘露糖苷衍生物，所有衍生物均带有可用于与硅酮表面共价结合的连接臂。我们建立了一种基于甘露糖苷修饰颗粒与流式细胞术的高通量竞争检测方法，可直接测定甘露糖苷配体与fim+ 大肠杆菌83972之间的结合亲和力。本研究证实，细菌黏附与生物膜形成与固定化甘露糖苷配体的结合亲和力密切相关。基于质谱的蛋白质组学分析显示，不同甘露糖苷表面生物膜所分泌的细胞外聚合物（extracellular polymeric substance, EPS）的蛋白质组存在显著差异，该差异可能与生物膜稳定性相关。