Submitted to: European Association of Fish Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: 6/18/2009
Publication Date: 9/14/2009
Citation: Klesius, P.H., Aksoy, M., Shoemaker, C.A., Evans, J.J. 2009. Flavobacterium columnare: Chemotaxis and adhesion to channel catfish mucus is mediated by lectin-like capsular substances. 14th European Association of Fish Pathologists. International Conference Prague, Czech Republic september 14-19, 2009. p. 54.
Technical Abstract: Flavobacterium columnare is an important Gram-negative pathogen of fresh water fish that may cause chronic skin lesions and severe mortality. Isolates of F. columnare belong to either the virulent genomovar II or the less virulent genomovar I. Chemotaxis and adhesion assays were conducted in vitro using pooled mucus samples from the skin epithelial surface of healthy channel catfish, Ictalurus punctatus. In a previous study, skin mucus was demonstrated to induce a greater chemotactic response in genomovar II than in genomovar I isolates. In the present study, we found that F. columnare adhesion to skin epithelial mucus was unrelated to the genomovar I or II status of the isolates. Chemotaxis and adhesion were significantly reduced following treatment of the bacterial cells with sodium periodate. Capsular staining showed a loss of capsule following sodium periodate oxidation. Incubation of mucus with D-mannose resulted in significant reduction of chemotaxis. Incubation of mucus with D-glucose or D-galactosamine resulted in significantly decreased adherence. The results demonstrate that a carbohydrate binding substance (lectin-like) present in the capsule is responsible for the chemotaxis and adhesion of F. columnare to the skin epithelial mucus. However, the sugar receptors in the skin epithelial mucus were different for the chemotactic response and adherent response of F. columnare. The results suggest that F. columnare pathogenesis involves both chemotaxis and adhesion to skin epithelial mucus that is mediated by lectin-like capsular substance.