Vibrio species associated with mortality of sharks held in captivity.

Two urease-positive Vibrio spp. were isolated from a brown shark ( Carcharhinus plumbeus) that died in captivity at a national aquarium. Morphological, biochemical, and molecular genetic studies revealed one of the isolates to be V. damsela; the other isolate was unique and has been classified as V. carchariae sp. nov. Both V. damsela and V. carchariae were found to be virulent for spiny dogfish ( Squalus acanthias), causing death in less than 18 hours after intraperitoneal injection of ca. 4×10 cells. V. damsela was strongly cytotoxic for Y1 adrenal cell monolayers; V. carchariae exhibited weak cytotoxicity for Y1 cells. V. damsela contained cryptic plasmids and both isolates were urease positive. V. carchariae was able to utilize urea as sole source of carbon and nitrogen. [ABSTRACT FROM AUTHOR]