Virulence ofVibrio vulnificus: association with utilization of transferrin-bound iron, and lack of correlation with levels of cytotoxin or protease production

16 Vibrio vulnificus strains isolated from clinical and environmental sources were studied. 6 strains (4 clinical and 2 environmental) were virulent in both an infant mouse intragastric inoculation model and an iron-loaded adult mouse model; there was a close correlation between results in the two models. Virulence was not associated with increased in vitro production of extracellular cytotoxin-hemolysin or protease. There was some correlation between virulence and the ability of a strain to grow in an iron-limited medium, with a significant association observed between virulence and utilization of transferrin as an iron source. Our results suggest that the ability to make use of available host iron is an important determinant for pathogenicity of V. vulnificus.