The ability of Vibrio vulnificus to use a synthetic hydrophilic heme compound, Fe-TPPS, as a single iron source

Vibrio vulnificus, an opportunistic human pathogen, can obtain iron from a variety of heme proteins. This process involves the digestion of heme prote ins by an exoprotease to liberate protoheme (iron-protoporphyrin IX). In th e present study, we tested whether this pathogen also uses a synthetic heme compound, Fe-alpha,beta,gamma,delta-tetraphenylporphine tetrasulfonic acid (Fe-TPPS), as an iron source. When inoculated into a medium containing Fe- TPPS, V. vulnificus L-180 multiplication was seen to be dependent on the co ncentration of the synthetic heme compound; a mutant lacking the ability to utilize protoheme did not multiply. Cells of the strain grown under the ir on-restricted condition showed time-dependent uptake of Fe-TPPS. The abilit y to use either protoheme or Fe-TPPS was significantly reduced by the addit ion of an excess amount of free TPPS or Cu-TPPS. The data suggest that, V. vulnificus may assimilate Fe-TPPS, at least partially, through the same sys tem as that for protoheme. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.