Journal of Dalian Ocean University  2009, Vol. 24 Issue (3): 200-205 DOI: 10.3969/j.issn.1000-9957.2009.03.003 |
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| Identification and characteristics of a pathogenic bacterial strain from channel catfish lctalurus punctatus |
| CHEN Lin, TAN Ai-ping, ZOU Wei-min
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| 1. Department of Biology and Environment Engineefing,Guangzhou City Polytechnic College,Guangzhou 510045 ,China; 2. Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China |
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Abstract Strain IP0004 as a pathogenic strain was isolated from the liver of diseased channel catfish （lctalurus punctatus）. The isolated strain was proved to be classified as Plesiomonas shigelloides by morphological, physiological and biochemical analysis, and sequencing of 16S rRNA. The bacterium was Gram positive, secreted acid production from glucose, maltose and trehalose and had monotrichate flagellum without spores. ONPG test showed that the strain had positive ornithine decarboxylase, lysine decarboxylase, arginine dihydrolase, β - galaetosidase, and α- galactosidase, and negative urease, lipase, β- glucosidase, N - Acetyl -β- Glucosaminidase, β- Glucuronidase, and L - Aspartic acid Arylamidase. The optimum isolation was observed at a salinity of 0 - 25, pH 5 - 10, temperature of 37℃. The similarities of the 16s rRNA gene sequences in the strain IP0004 to other Plesiomonas shigeUoides were more than 99%. Phylogenetic tree based on these sequences showed that the strain IP0004 clustered together with Plesiomonas shigelloicles. The similarities of COMP（ cytotoxic outer -membrane protein） gene of the isolation to other COMP genes of Plesiomonas shigeUoides are more than 99.9%, so strain IP0004 has COMP gene. The test of sensitivities of strain IP0004 to 15 kinds of antibiotics revealed that IP0004 was sensitive to drugs such as ceftriaxone, cefradine, cefamezin, and ofloxacin, but not to novobiocin, rifampicine, and sulfamethoxazolum.
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Published: 30 December 2016
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