SOME BIOCHEMICAL CHARACTERISTICS AND THE OCCURRENCE DEGREE OF PRESENCE OF AEROMONAS-SALMONICIDA IN CALIFORNIAN TROUT (ONCORHYNCHUS-MYKISS)

The objective of this work was to determine the abundance of the bacte rum Aeromonas salmonicida, the cause of the disease furunculosis, in C alifornian trout (Oncorhynchus mykiss), as well as certain biochemical activities of the isolated strains. Ten strains of the species Aeromo nas salmonicida were isolated from samples taken from changed skin are as on fish raised in fisheries. Two strains were isolated in Fishery I , one strain in Fishery II, four strains in Fishery Ill, and three str ains in Fishery IV. The cause of the disease was not found in samples of internal organs of the diseased fish. The isolated strains of bacte ria had the following biochemical activities in the respective media: H2S production was not established; nitrates were positive; catalase w as positive; V. P. and indol negative, esculin positive, hemolysis pos itive; there was degradation of gelatin, as well as of glucose, arabin ose, and manitol. Saccharose degradation was not found. All bacteria s trains were immobile. The strains grew at a temperature of 22-23 degre es C, and did not grow at 35-37 degrees C. Colonies of the examined st rains formed a brown pigment between the third and fifth days. The bio chemical activities of the isolated strains were identical to the acti vities of the standard strain of Aeromonas salmonicida which served as a control. The isolated strains of Aeromonas salmonicida, originating from different samples taken from diseased places on trout skins, gav e a positive reaction for agglutination with the ''O'' antiserum again st Aeromonas salmonicida, while the agglutination reaction with the '' O'' antiserum against Aeromonas hydrophila was negative.