Classification of marine luminous bacteria isolated from farming seashells and Scophthatmus maximus
从养殖贝类和大菱鲆分离的海洋发光弧菌的分类地位分析

Marine luminous vibrios are important opportunistic pathogens in marine aquaculture. 16 luminous bacteria were isolated from the soft bodies of clams (Ruditapes philippinarum) and of oysters (Saccostrea cucullata) collected in the aquacultural farms near Jinjiang in Fujian Province and from the gastroenteric contents of turbot fish (Scophthatmus maximus) from Baltic Sea. To ascertain the taxonomic statuses of the bacteria, four methods were applied. The ARDRA (amplified ribosomal DNA restriction analysis) fingerprints of 16 strains showed three different operational taxonomic units (OTUs). According to the bacterial morphology of colonies and cells, the ARDRA fingerprints, and sample sources, five strains were sent for sequencing of 16S rDNA. The results of phylogenetic analysis of 16S rDNA evinced that they are all belong to genus Vibrio, and most closely related to V. fischeri, V. orientalis, V. azureus, and V. campbellii respectively. This result indicates that ARDRA method has limitation when distinguishing different species that are closely related from the same genus. Biolog C-Source-Utilizing analysis could not identify marine bacteria to species level according to the database, but could classify the closely related bacteria species to the same group. The results of drug sensitive tests by the K-B method showed that the closely related species also had similar drug sensitivities. All of the five strains were sensitive to sulfamethoxazole and gentamicin, which will be helpful to treat potential luminous bacteria diseases in marine aquaculture. The combination of the four methods could classify the bacteria species to different groups and this could be the basis for further physiological characterization.