Presence of high-affinity iron uptake systems in fish-isolated and environmental strains of Vibrio anguillarum serotype O3

This work describes the presence of high-affinity iron uptake systems in Vi brio anguillarum serotype O3 strains (subgroups A and B), isolated from dis eased fish and environmental samples, as well as the presumptive effect of iron on their virulence. All strains demonstrated an ability to grow under iron-limiting conditions, production of catechol-type siderophores and synt hesis of iron-regulated outer membrane proteins. However, clear differences were found depending on the isolation source, suggesting a more efficient iron uptake system in fish-isolated strains. Comparing the iron-regulated o uter membrane protein profiles with those described for O1 and O2 serotypes , we found a protein which is specific for serotype O3, and another one tha t allows the differentiation of serotype O3 fish isolates from environmenta l strains. Moreover, only the strains showing this protein increased their virulence when iron was added to the inoculum, in pathogenicity assays. (C) 2001 Federation of European Microbiological Societies. Published by Elsevi er Science B.V. All rights reserved.