Purification of a mannose/glucose-specific hemagglutinin/lectin from a Vibrio cholerae O1 strain

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.

Adhesion of Vibrio cholerae to granular starches

Cholera is a severe diarrheal disease caused by specific serogroups of Vibrio cholerae that are pathogenic to humans. Cholera can become epidemic and deadly without adequate medical care. Appropriate rehydration therapy can reduce the mortality rate from as much as 50% of the affected individuals to <1%. Thus, oral rehydration therapy (ORT) is an important measure in the treatment of this disease. To further reduce the symptoms associated with cholera, improvements in oral rehydration solution (ORS) by starch incorporation were suggested. Here, we report that V. cholerae adheres to starch granules incorporated in ORS. Adhesion of 98% of the cells was observed within 2 min when cornstarch granules were used. Other starches showed varied adhesion rates, indicating that starch source and composition play an important role in the interaction of V. cholerae and starch granules. Sugars metabolized by V. cholerae showed a repressive effect on the adhesion process. The possible mechanisms involved are discussed. Comparing V. cholerae adhesion with the adhesion of other pathogens suggests the involvement of starch degradation capabilities. This adhesion to granular starch can be used to improve ORT.