Abstract: A pathogen（FS20100810） was isolated from ulcered snakehead, Channa maculata, which was proved to be the pathogenic bacterium of the disease by re-infection experiments. The strain was found to be gram negative, anaerobic, bacilliform in shape and motile. It had no capsule and gemma,and utilized glucoses, sucrose, maltose, mannitol, esculin as energy and its oxidase reaction, catalase reaction, indole and M.R. test were positive. The half lethal concentration value for the strain to the snakehead was 6.83 ×10^5 cfu/mL. Homology analysis showed that it had the high similarity to Aeromonas hydrophila with 99.6% similarity. The drug sensitivity showed the strain was sensitive to ofloxacin, ceftriaxone, and Cefotamine was intermediately sensitive to complex sinomin and was resistant to oxazocilline, penicillin G and ampicillin. There were obvious pathological changes in the tissues of the gills, cardiac muscles, livers, kidneys, spleens and intestines in the snakeheads challenged by strain FS20100810 by pathohistological observation.
2011, Vol. 26 
