Isolation of Carnobacterium piscicola and an unidentified Gram-positive bacillus from sexually mature and post-spawning rainbow trout Oncorhynchus mykiss

Blochemica1 and electrophoretic studles were done on bacterial isolates collected from rainbow trout Oncorhynchus mykiss from 2 private hatcheries In the Pacific Northwest, USA. Five isolates onginated from post-spawning mortalities and morbidities; 2 other isolates were obtained from reproductively active 17 mo old rainbow trout. After 35S-methion~ne-labeled protein lysates were prepared from each isolate, correlation coefficients of electrophoretic proflles were calculated for each pair of isolates using an automated m~crobiological identification system (AMBIS) The Gram-pos~tive isolates appeared to represent 1 or possibly 2 genera: Carnobacterium and Lactobacillus Five isolates were identified as C. piscicola and two (106891,106892) did not correspond to any previously described species. Comparisons based upon correlation coefficients calculated for the 2 unidentified isolates and for biochemically similar strains, including C. piscicola (ATCC 15434), L. alimentarius (ATCC 29643) and L. homohiochi (ATCC 15434), resulted in values no greater than 0.792. This dissimilarity suggests that the 2 unidentified isolates represent a different blotype of C. plscicola or a previously undescribed species of Lactobacillus.