Aeromonas trota strains, which agglutinate with Vibrio cholerae O139 Bengal antiserum, possess a serologically distinct fimbrial colonization factor.

Pili of Aeromonas trota strain 1220, which agglutinates with Vibrio cholerae O139 Bengal antiserum, were purified and characterized. The molecular mass of the subunit protein was estimated to be 20 kDa and the pl was 5 center dot 4. The pili were immunologically unrelated to the other Aeromonas pili reported so far. However, the N-terminal amino acid sequence of the subunit pilin was similar to those of the pilins from other Aeromonas pili reported previously. Neither A. trota cells nor pili purified from strain 1220 agglutinated human and rabbit erythrocytes, but both adhered to the rabbit intestine. Bacterial cells pretreated with antipilus antibody (Fab portion) failed to adhere to the rabbit intestine. Moreover, bacteria did not adhere to the rabbit intestine pretreated with the purified pili. This pilus antigen was not detected in V. cholerae O139 Bengal and other Aeromonas spp. These findings suggest that the pilus of the A. trota strain is a novel colonization factor of Aeromonas spp.