The internal surface of the animal gastrointestinal tract is covered by microbial biofilms. They play an important role in the development and functioning of the host organism and protect it against pathogens. Microbial communities of gastrointestinal biofilms are less elucidated than luminal microbiota. Therefore, the studies of biofilm formation by gastrointestinal microorganisms are a topical issue. For the first time, we report the formation of a biofilm in vitro by the strains of bioluminescent bacteria isolated from the intestines of marine fish. These bacteria exhibit co-aggregation and tend to attach to solid surfaces. The attachment of cells is accompanied by appearance of the pili. Then, we observed the formation of microcolonies and the production of extracellular polymer substances (EPSs) connecting bacterial cells into an integrated system. The presence of acidic polysaccharides is shown in the EPS when using the ruthenium red staining. Acidic polysaccharides in this matrix is a biochemical evidence of microbial biofilms. On the fibers of the polymer matrix, these bacteria form the “mushroom body”-type structures. Matured biofilms exhibit a specific three-dimensional architecture with pores and channels formed by cells and EPS. We also demonstrated the formation of a biofilm by binary culture of the luminous enterobacterium Kosakonia cowanii and a Gram-positive Macrococcus sp. The data obtained help to understand the role of these bacteria in the intestines of fish. They lead to a new study in the field of investigation of the intestinal microbiome of fish.

动物胃肠道的内表面被微生物生物膜覆盖。它们在宿主生物的发育和功能中发挥重要作用，并保护其免受病原体侵害。胃肠道生物膜的微生物群落不如管腔微生物群阐明。因此，胃肠道微生物生物膜形成的研究是一个热门话题。我们第一次报告了从海鱼肠道中分离出的生物发光细菌菌株在体外形成生物膜的情况。这些细菌表现出共聚集并倾向于附着在固体表面上。细胞的附着伴随着菌毛的出现。然后，我们观察到微菌落的形成和细胞外聚合物物质 (EPS) 的产生，将细菌细胞连接成一个完整的系统。当使用钌红染色时，EPS中显示酸性多糖的存在。该基质中的酸性多糖是微生物生物膜的生化证据。在聚合物基质的纤维上，这些细菌形成“蘑菇体”型结构。成熟的生物膜表现出特定的三维结构，具有由细胞和 EPS 形成的孔和通道。我们还通过发光肠杆菌的二元培养证明了生物膜的形成 在聚合物基质的纤维上，这些细菌形成“蘑菇体”型结构。成熟的生物膜表现出特定的三维结构，具有由细胞和 EPS 形成的孔和通道。我们还通过发光肠杆菌的二元培养证明了生物膜的形成 在聚合物基质的纤维上，这些细菌形成“蘑菇体”型结构。成熟的生物膜表现出特定的三维结构，具有由细胞和 EPS 形成的孔和通道。我们还通过发光肠杆菌的二元培养证明了生物膜的形成Kosakonia cowanii和革兰氏阳性巨球菌属。获得的数据有助于了解这些细菌在鱼肠中的作用。它们导致了鱼类肠道微生物组研究领域的一项新研究。