Hemagglutinating activity is directly correlated with colonization ability of shigellae in suckling mouse model

The aim of the present study was to explore a new approach based on the hemagglutination (HA) assay to understand the colonization ability of Shigella spp. To study colonization ability, an animal model of 4-day-old suckling mouse, was exploited. We characterized the HA activity of 48 Shigella strains, with erythrocytes collected from rabbit, guinea pig, chicken, and sheep. Only rabbit and guinea pig erythrocytes showed positive HA reactions in most of the cases. On the basis of HA pattern, 4 strains from each serogroup were selected for in vivo colonization studies. Our results showed a positive correlation between HA activity and colonization ability of the strains belonging to different serogroups (groups A, B, C, and D) of Shigella. In all 4 serogroups, high HA titer was associated with greater intestinal colonization.