ABSTRACT

Biofilm is a predominant lifestyle of bacteria that comprises of cells as collectives enmeshed in a polymeric matrix. Biofilm formation is vital for bacterial species as it provides access to nutrients and protects the cells from environmental stresses. Here we show that interference in biofilm matrix production is a strategy by the competing bacterial species to reduce the ability of the other species to colonize a surface. Escherichia coli colonies that differ in matrix production display different morphologies on Congo red agar media, which we exploited for screening bacterial isolates capable of inhibiting the matrix. The cell-free supernatants from growth culture of the screened isolates impaired uropathogenic E. coli (UPEC) UTI89 strain's biofilm. A physicochemical analysis suggested that the compound could be a glycopeptide or a polysaccharide. Isolates that inhibited matrix production belonged to species of the family Enterobacteriaceae such as Shigella, Escherichia, Enterobacter and Salmonella. Competition experiments between the isolates and the UPEC strain resulted in mutual inhibition, particularly during biofilm formation causing significant reduction in productivity and fitness. Furthermore, we show that Salmonella strains competitively excluded the UPEC strain in the biofilm by inhibiting its matrix production, highlighting the role of interference competition.

中文翻译：

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沙门氏菌对基质的抑制作用从生物膜中排除了尿毒症性大肠杆菌

摘要

生物膜是细菌的主要生活方式，它由细胞组成，这些细胞聚集在聚合基质中。生物膜的形成对于细菌物种至关重要，因为它可以提供营养并保护细胞免受环境压力。在这里，我们表明生物膜基质生产中的干扰是竞争性细菌物种降低其他物种在表面定殖能力的一种策略。在基质产生上不同的大肠杆菌菌落在刚果红琼脂培养基上显示出不同的形态，我们利用它来筛选能够抑制基质的细菌分离株。筛选出的分离物生长培养的无细胞上清液会损害尿路致病性大肠杆菌（UPEC）UTI89菌株的生物膜。物理化学分析表明该化合物可以是糖肽或多糖。抑制基质产生的分离物属于肠杆菌科的物种，如志贺氏菌，大肠杆菌，肠杆菌和沙门氏菌。分离株和UPEC菌株之间的竞争实验导致相互抑制，特别是在生物膜形成期间，导致生产力和适应性显着降低。此外，我们显示沙门氏菌菌株通过抑制其基质产生，竞争性地排除了生物膜中的UPEC菌株，从而突出了干扰竞争的作用。