VIBRIO TAPETIS SP-NOV, THE CAUSATIVE AGENT OF THE BROWN RING DISEASE AFFECTING CULTURED CLAMS

A taxonomic characterization was carried out on strains of the bacteri a that cause the brown ring disease of clams. On the basis of their ph enotypic and genotypic characteristics, these strains can be considere d to constitute a new taxonomic unit, distinct from other Vibrio speci es. The guanine-plus-cytosine content of the strains ranged between 42 .9 and 45.5 mol% (43.2 mol% for the proposed type strain). DNA-DNA hyb ridization studies showed 100% intragroup relatedness, but levels of g enetic relatedness to the reference strains of different Vibrio specie s tested ranged between 15 and 58%. The strains have all the propertie s characteristic of the genus Vibrio and can be clearly differentiated from other species of this genus by their growth at 4 degrees C and t heir negative responses for growth at 30 degrees C and in 6% NaCl, arg inine dehydrolase, lysine decarboxylase, ornithine decarboxylase, and Voges-Proskauer reaction. The name Vibrio tapetis is proposed for the new species; strain B1090 (CECT 4600) is the type strain.