Open AccessInfection of Tilapia Oreochromis sp. by Vibrio vulnificus in Freshwater and Low‐salinity Environments
Author(s) -
Chen ChunYao,
Chao ChiaBen,
Bowser Paul R.
Publication year - 2006
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/j.1749-7345.2006.00010.x
Subject(s) - biology , tilapia , oreochromis , vibrio vulnificus , microbiology and biotechnology , 16s ribosomal rna , edwardsiella tarda , bacteria , fishery , fish <actinopterygii> , genetics
The first isolation of Vibrio vulnificus in southern Taiwan from hybrid tilapia Oreochromis sp. raised in freshwater and brackish water environments is documented in this report. The infection was only found in fish in ponds where the salinity was less than 10 ppt. Tilapia raised in water of higher salinities in the same region were not affected. Grossly visible signs of infection included dark coloration, lethargy, and external hemorrhage and ulceration of the skin. The most prominent internal signs of infection included splenomegaly and severe hemorrhagic lesions in the liver. Septicemia was documented in moribund fish. All bacterial isolates from moribund fish were tested by polymerase chain reaction, using V. vulnificus hemolysin/cytolysin gene‐specific primers. Sequence data from the 16S ribosomal RNA gene suggest that these isolates were V . vulnificus . The isolates were indole and mannitol positive, characteristics shared by human clinical isolates and isolates from freshwater European eel, Anguilla anguilla . The isolates from tilapia were unique in that they were negative for ornithine decarboxylase and citrate.