Characterization of strains of Vibrio splendidus and V. tapetis isolated from corkwing wrasse Symphodus melops suffering vibriosis

Two vibrio bacteria pathogenic to the corkwing wrasse Symphodus melops were isolated. Vibriosis-inducing strain LP1 was isolated as the dominanting bacterium in kidney samples of dead and moribund wrasse from a population suffering vibriosis and high daily mortality in 1998 on the Norwegian west coast. The other vibriosis-inducing strain, LP2, was isolated from wrasse captured the following year. Re-infection experiments have confirmed that these strains cause vibriosis in corkwing wrasse. Both strains were typical vibrios sharing the traits of fermentative Gram-negative curved rods with motility and a positive oxidase reaction. Detailed biochemical and genetic characterisation revealed a close affiliation to known species of the marine environment. The first isolate, LP1, is a form of the ubiquitous seawater organism Vibrio splendidus, while the second isolate, LP2, is closely related to V. tapetis (previously only known as the brown ring disease agent in clams). Identification of the new wrasse pathogens V. splendidus LP1 and V. tapetis LP2 is facilitated by break points observed in this study.