Hydrophobic and Haemagglutinating Properties of Renibacterium salmoninarum

SUMMARY: Twenty-five strains of Renibacterium salmoninarum, from diverse geographical locations, were all hydrophobic when tested by ammonium sulphate aggregation and adherence to hydrocarbons. In addition, all strains caused haemagglutination of rabbit erythrocytes, but not of erythrocytes from salmonid fish. The hydrophobic and haemagglutinating properties were further characterized for R. salmoninarum ATCC 33209 (the type strain). Treating the bacteria with protease K or trypsin decreased hydrophobicity but had no effect on the ability to haemagglutinate rabbit erythrocytes. Heating the bacteria to 62 or 100 °C reduced hydrophobicity and removed the haemagglutinin from the cell surface. The haemagglutinin may be the heat-stable bacterial antigen extracted from the tissue of infected fish in serodiagnostic procedures.