Biological and serological characterization of a non-gliding strain of Tenacibaculum maritimum isolated from a diseased puffer fish Takifugu rubripes

Abstract

Tenacibaculum maritimum is a Gram-negative, gliding marine bacterium that causes tenacibaculosis, an ulcerative disease of marine fish. The bacterium usually forms rhizoid colonies on agar media. We isolated T. maritimum that formed slightly yellowish round compact colonies together with the usual rhizoid colonies from a puffer fish Takifugu rubripes suffering from tenacibaculosis, and studied the biological and serological characteristics of a representative isolate of the compact colony phenotype, designated strain NUF1129. The strain was non-gliding and avirulent in Japanese flounder Paralichthys olivaceus in immersion challenge test and showed lower adhesion ability to glass wall in shaking broth culture and to the body surface of flounder. It lacked a cell-surface antigen commonly detected in gliding strains of the bacterium in gel immunodiffusion tests. SDS-PAGE analysis showed different polypeptide banding patterns between NUF1129 and gliding strains. Like gliding strains, NUF1129 exhibited both chondroitinase and gelatinase activities, which are potential virulence factors of the bacterium. These results suggest that some cell-surface components related to gliding and adhesion ability are implicated in the virulence of T. maritimum.