The name Lactobacillus piscicola sp. nov. is proposed for a group of 17 bacterial strains that were isolated from diseased rainbow trout (Salmo gairdneri), cutthroat trout (Salmo clarki), and chinook salmon (Oncorhynchus tshawytscha). This bacterium was found most frequently in infected fish which had suffered some form of stress, such as that which occurs at spawning. Occasionally, pathological signs in the internal organs or skin were observed. Phenotypically, L . piscicola belongs to the family Lactobacillaceae and can be distinguished from other species of Lactobacillus by its morphology and physiological characteristics. DL-Lactic acid was produced homofermentatively from glucose. Diaminopimelic acid was present in the cell wall peptidoglycan. The 17 isolates were closely related genetically, as demonstrated by similar percent guanine-plus-cytosine contents (35 mol%) and high deoxyribonucleic acid reassociation values, both characteristics of a single species. The isolates exhibited less than 10% deoxyribonucleic acid reassociation with other reference Lactobacillus strains with similar guanine-plus-cytosine contents. Strain B270 (= ATCC 35586), which was isolated in 1970 from diseased cutthroat brood trout at Bandon Hatchery in Oregon, is designated the type strain of this new species of Lactobacillus.A bacterium with characteristics resembling those of a Lactobacillus has been isolated by workers in our laboratory from rainbow trout (Salmo gairdneri) and cutthroat trout (Salmo clarki) for more than 25 years at various hatcheries in Oregon. These isolations have occurred most frequently from fish 1 year old and older which may have experienced stress, such as that associated with handling and spawning. The pathological signs have been varied and include septicemia, distention of the abdomen, splenomegaly, accumulation of ascites fluid, large muscular abcesses, internal hemorrhaging, and blood cavities or blisters under the skin. Various combinations of these disease signs have been observed in chronically infected trout. Lactobacilli have been isolated from a variety of salmonid (14) and nonsalmonid species (43). Two strains isolated in our laboratory from diseased brood trout were examined previously, but the taxonomic status of the isolates was never determined (N. Sriranganathan, Ph.D. thesis, Oregon State University, Corvallis, 1974).Lactobacilli are commonly found in fermenting plant and animal products and also in the oral cavities and intestinal tracts of warm-blooded animals, including humans (4). Pathogenicity in warm-blooded animals, although rare, has been reported (2,20,50). The possible role of lactobacilli as the cause of disease in salmonid fish has been described previously (8, 40, 41), but the bacterium associated with the condition has not been identified. In this study, biochemical tests and deoxyribonucleic acid (DNA) hybridization data were used to compare and classify the Lactobacillus strains found in salmonid fish. Our results indicate that this organism represents a new species of ...

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A new bacterial pathogen of chinook salmon (Oncorhynchus tshawytscha) was isolated from fish in Oregon's Rogue River. The bacteria are biochemically and serologically related to strains of Edwardsiella tarda. Initially isolated from chinook salmon, the bacteria were also pathogenic for steelhead and rainbow trout (Salmo gairdneri), and channel catfish (Ictalurus punctatus). The 50% lethal doses for chinook salmon, steelhead trout, and channel catfish injected intraperitoneally and maintained in 18°C water were 4.1 x 106, 5.6 x 106, and 4.0 x 105, respectively. When chinook salmon and rainbow trout were injected intraperitoneally and held in 12°C water, the mean lethal doses were 6.4 x 107 and 1.7 x 106, respectively. The invasiveness of the organism was low in steelhead trout exposed to the bacteria by the waterborne route. The optimum growth temperature of the bacteria in brain heart infusion broth was approximately 35°C. The guanine plus cytosine content of DNA obtained from E. tarda isolated from salmon was 59 mol%.

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Alcohol-producing strains of Clostridium beijerinckii (Clostridium butylicum) produce, besides acetone, either n-butanol and ethanol or n-butanol, ethanol, and isopropanol as their characteristic products. Alcohol dehyrodgenase has been isolated from a strain (NRRL B593) of C. beijerinckii producing isopropanol and from a strain (NRRL B592) not producing isopropanol. Butanol-ethanol dehydrogenase activities were present in both strains, but isopropanol dehydrogenase activity was present only in the isopropanol-producing strain. The butanol-ethanol dehydrogenase of strain NRRL B592 had Mfr 66,000 and a. Km of 6 ,uM for butyraldehyde. In contrast, the butanol-ethanol-isopropanol dehydrogenase of strain NRRL B593 had a Mr 100,000 and Kms of 9.5 and 1.0 mM for butyraldehyde and acetone, respectively. In a purification by four different types of separatory methods (DEAE-cellulose, hydroxyapatite, Sephacryl S-300, and Matrex Gel Red A), butanolethanol-isopropanol dehydrogenase activities of strain NRRL B593 were purified up to 200-fold (10 to 30% yield), and these activities were not separated. Gel electrophoresis followed by activity stain also revealed distinct mobilities for the butanol-ethanol dehydrogenase of strain NRRL B592 and the butanol-ethanolisopropanol dehydrogenase of strain NRRL B593. In cell extracts from both strains, a higher alcohol dehydrogenase activity was measured with NADP(H) than with NAD(H). The 150to 200-fold-purified alcohol dehydrogenase from strain NRRL B593 did not show any NAD(H)-linked activities. The Km for NADPH was 31 ,uM (with butyraldehyde as cosubstrate) and 18 ,uM (with acetone as cosubstrate) for the alcohol dehydrogenase of strain NRRL B593. This study showed that the alcohol dehydrogenases from two strains of C. beijerinckii differed significantly.