Hemagglutination properties and adherence ability of Aeromonas hydrophila.

Human diarrheal isolates and enterotoxigenic strains of Aeromonas hydrophila are strong hemagglutinators with human blood cells. Sugar inhibition studies and yeast coagglutination tests with 11 selected strains revealed six different hemagglutination mechanisms for this species. These were characterized by inhibition by L-fucose, inhibition by D-galactose, inhibition by D-mannose, and two distinguishable mechanisms which were inhibited by either L-fucose or D-mannose, one being pilus mediated. Inhibition of hemagglutination by another strain required a combination of D-galactose and D-mannose. The hemagglutinating strains also attached well to human blood cells and buccal epithelial cells, with as many as 55% of the cells of a culture attaching successfully. In some cases the attachment to buccal epithelial cells appeared to involve mechanisms different from those used for hemagglutination.