Extracellular and surface-bound biological activities of Vibrio fluvialis, Vibrio furnissii and related species.

Twenty-seven Vibrio strains were assessed for virulence-associated biological activities, including iron chelation, hydrolases, haemolysis and haemagglutination. All strains hydrolysed DNA, chitin, gelatin and casein, produced siderophores, and lysed red blood cells. All V. fluvialis, V. cholerae and V. mimicus strains exhibited diverse lipolytic activity distinct from more discriminate lipolysis by V. furnissii. V. furnissii manifested fibrin and mucin hydrolysis but no phosphate or esculin hydrolysis, for which V. fluvialis varied. No strains hydrolysed urea, alginate or keratin. V. fluvialis, V. furnissii and V. mimicus strains failed to exhibit the mannose-sensitive haemagglutination typical of V. cholerae. Some activities may distinguish otherwise phenotypically similar species. Species tested commonly possessed biological activities that may contribute to virulence, although there was no apparent correlation with isolation from human sources.