Agglutination Typing of Vibrio anguillarum Isolates from Diseased Fish and from the Environment.

Agglutinating activity was widely distributed among 101 Vibrio anguillarum strains of different origin and three Vibrio ordalii strains from salmonids. The spectrum of cells which were agglutinated comprised yeast cells and human (type O), poultry, guinea pig, and trout erythrocytes, whereas ovine, bovine, and tanned bovine erythrocytes were not affected. Mannose-sensitive hemagglutination, mannose-resistant hemagglutination, and non-agglutinating strains were recognized. The three V. ordalii strains showed mannose-resistant hemagglutination, whereas V. anguillarum exhibited either mannose-sensitive hemagglutination or was non-agglutinating. Among V. anguillarum, sensitivity to d-galactose and l-fucose occurred sporadically. An agglutination typing scheme was developed for strains of V. anguillarum based on the agglutination pattern of human, poultry, guinea pig, and trout erythrocytes and yeast cells. Eight different agglutination types (A through H) were defined. The distribution of these types among fish pathogenic and environmental V. anguillarum strains were studied. The application of the typing scheme in ecological and epidemiological studies and for preventive medical purposes is discussed.