Papadopoulou A, Dalsgaard I, Lindén A, Wiklund T
Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland.
National Veterinary Institute, Technical University of Denmark, Frederiksberg C, Denmark.
J Fish Dis. 2017 Oct;40(10):1309-1320. doi: 10.1111/jfd.12603. Epub 2017 Feb 11.
The adherence of Flavobacterium psychrophilum to surfaces of epithelial tissues has been inconclusively suggested as a mechanism, which enables the bacterium to invade the host. Hence, the present study aimed to examine the adherence of the cells of two colony phenotypes, smooth and rough, of F. psychrophilum to mucosal tissues of rainbow trout fry and to test the skin mucus as a nutrient for the growth of F. psychrophilum. Fish were immersed in water containing 10 CFU mL F. psychrophilum for each colony phenotype. Mucosal tissue samples from fins, gills, skin and eyes, and swab samples from spleen and kidney were taken and inoculated onto TYES agar plates. Colony phenotypes of F. psychrophilum were identified and number of colonies counted. The results showed that cells of both phenotypes initially (0 h) adhered to all mucosal surfaces, but only the rough cells were still present on tissues 1 h post-immersion. Both phenotypes showed a tissue tropism with the fin tissue being the most adhered. Furthermore, skin mucus promoted the growth of both colony phenotypes. We suggest that the growth of F. psychrophilum cells in skin mucus apparently facilitates the bacterial adherence to mucosal surfaces, and the subsequent invasion into the host.
嗜冷黄杆菌附着于上皮组织表面被认为是其侵入宿主的一种机制，但尚无定论。因此，本研究旨在检测嗜冷黄杆菌两种菌落表型（光滑型和粗糙型）的细胞对虹鳟鱼苗黏膜组织的附着情况，并测试皮肤黏液作为嗜冷黄杆菌生长营养物质的作用。将鱼分别浸入含有每种菌落表型10 CFU/mL嗜冷黄杆菌的水中。采集鳍、鳃、皮肤和眼睛的黏膜组织样本以及脾脏和肾脏的拭子样本，并接种到TYES琼脂平板上。鉴定嗜冷黄杆菌的菌落表型并计数菌落数量。结果表明，两种表型的细胞在最初（0小时）均附着于所有黏膜表面，但仅粗糙型细胞在浸泡1小时后仍存在于组织上。两种表型均表现出组织嗜性，鳍组织附着最多。此外，皮肤黏液促进了两种菌落表型的生长。我们认为，嗜冷黄杆菌细胞在皮肤黏液中的生长显然有助于细菌附着于黏膜表面，并随后侵入宿主。
