Surface properties and ultrastructure of Edwardsiella species.

Twenty-two strains of Edwardsiella representing the three currently recognized species were evaluated for surface characteristics and ultrastructural morphology. All isolates tested possessed a high surface cell charge as detected by DEAE-cellulose chromatography; surface hydrophobicity was variable and strain but not species dependent. Two major types of adhesins detected by hemagglutination assays were identified: one was inhibited by D-mannose (mannose-sensitive hemagglutinin) and found on all three species, and a second was not inhibited by D-mannose (mannose-resistant hemagglutinin) and was principally associated with Edwardsiella tarda. The results of physiologic and ultrastructural studies suggest that both hemagglutinins are afimbrial adhesin proteins. The results of these studies suggest that there are a number of distinct surface and ultrastructural properties associated with each of the three Edwardsiella species.