A lipopolysaccharide-specific bacteriophage for Aeromonas salmonicida

Cell wall lipopolysaccharide (LPS) was identified as the receptor for the Aeromonas salmonicida bacteriophage strain 55R-1. Mutants of A. salmonicida resistant to phage 55R-1 were unable to adsorb phage 55R-1 and were shown to be defective in LPS structure. Purified A. salmonicida LPS inactivated phage 55R-1, but the O-polysaccharide and the core oligosaccharide portions of the LPS were ineffective. These results suggest that lipid A was required for receptor activity. Antibodies directed against LPS also inhibited phage adsorption.