Role of flagellum and chemotactic motility of Vibrio anguillarum for phagocytosis by and intracellular survival in fish macrophages

The role of the flagellum and chemotactic motility of Vibrio anguillarum</it> for phagocytosis by and intracellular survival in fish macrophages was determined using a wild-type strain, a mutant without the flagellum, a mutant with a truncated flagellum and a non-chemotactic mutant. For all strains, the numbers of intracellular bacteria were relatively low and fell steadily during the observation period. The presence of a flagellum did not influence the uptake by the macrophages, but the smooth swimming phenotype of a non-chemotactic mutant increased its intracellular presence. We suggest that this is due to an increased collision between the mutant and the macrophage, due to a higher average speed of the non-chemotactic mutant.